HABIT-CHANGE. Date: December This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF

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1 HABIT-CHANGE Integrated indicators of climate change (cc) induced habitat changes in wetlands of the Biebrza National Park (BNP) contribution to Output (4.3.2; 4.3.5) and Date: December 2011 This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF

2 Contents: 1. Introduction Survey of the wetland environment Selecting characteristics of the soil environment and plant communities which are most sensitive to climate change driven pressures and determining variability scales for every attribute within the area examined Selection of habitat characteristics most senstive to climate change soils Evaluation of sensitivity of selected habitat properties to climate change soils Evaluation of the soil carbon content as indicator of climate change induced changes in wetland soils in the BNP Plant species and communities as integrated indicators of habitat changes Plant chemical composition bioindicator of habitat changes Evaluation of relationships between soil quality and element accumulation in plants Evaluation of relationships between the soil- and plant nutrient contents Prognosis of changes in soils and plant communities in the Biebrza National Park (Biebrza River valley) based on reconstruction of the past and forecast of the future local climate conditions Literature...55 [1]

3 Wetland habitat sensitivity to climate induced changes in the BNP was studied over the last two years, with the aim to found best and simplest, and at the same time, the most representative, indicators of changes in organic soils and vegetation of wetlands. Indicators of shortterm changes are of qualitative character, and are applied in order to determine trends of changes in the environment resulting from multiple pressures including climate change. The indicators of longterm changes are applied to the assessment of measurable/quantifiable habitat changes. The outcomes obtained recently as well as those discussed earlier (Ostrowska 2002, Ostrowska et al. 2006, Porębska 2003) as well as those resulting from expertises and literature analyses allowed to establish the following simple integrated indicators to be applied in habitat monitoring in BNP and other wetlands: 1. Soil carbon content is the best integrated indicator of longterm effects of cc induced changes in organic soils 2. Soil nitrogen content provides for the best assessment of cc induced changes in the soil environment for determining the short term effects 3. Contents of elements in soil solutions, in particular the contents of nitrogen and carbon may be used as valuable indicators of short term effects of cc induced changes Monitoring of wetland soils with the use of the aforementioned indicators is to be done at the following intervals: 1. Soil carbon content (indicator of longterm effects) shall be determined in 40 cm thick soil layer, on the established permanent plots, once every decade. 2. Short term effects may be assessed by determining either the soil nitrogen content or the contents of elements in soils solutions, every 2-3 years. Longterm effects of climate change in the vegetation of wetlands can be assessed with the use of indicators such as the increased presence of nitrophilous species which have a higher nutrient demand. This group of species embraces both those of the Class Artemisietea, including: Urtica dioica, Geranium robertianum, Galium aparine, Geum urbanum, Anthriscus silvestris, Galeopsis pubescens and Rumex obtusifolius and such species of the Class Querco-Fagetea as: Impatiens nolitangere and Aegopodium podgararia. In the BNP, in the drying riparian alder-ash wood, the above species occurred with high fidelity classes: III-V and with a high coefficients of species coverage. Another indicators of longterm habitat changes due to among others, climate warming may be the change in the community structure evidenced by an increased presence of accompanying species which are not typical of the original natural community. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [2]

4 1. Introduction Climate change driven impacts overlap with other environmental pressures of both natural and anthropogenic origin, and can be observed as multifaceted effects in natural habitats. The most conspicuous effects include changes in water and nutrient circulation, changes in phytocoenose structure changes and shifts in share and domination of syngenetic groups of plants (sums of species cover-abundance). This diversity of effects results in the diversity of assessment situations and requires many procedures and indicators to evaluate habitat changes locally. To this end, the single effect (selective) indicators are widely applied, including the indicators based on properties and functions of soils, species and communities whose performance can be directly associated with climate changes over time. As results from the authors earlier works and literature review, the list of selective indicators to assess climate change induced effects in ecosystems is very robust. In the literature there are recommended various indicators for the assessment of climate induced changes in ecosystems, e.g. geobotanical indicators including the Ellenberg values, distribution of plant species, plant phenology, Normalized Difference Vegetation Index (NDVI), soil water, water deficit and plant water requirement, to name only a few of the widely applied indicators (Sienkiewicz, Kloss 2001). Ellenberg indices of temperature, continentalism and moisture are recommended for the assessment of climate induced habitat changes (EEA). Such indicators as phytocoenose structure and species composition show net assignment to both abiotic parameters (soil conditions, light, air temperature, water availability) and biotic pressures (wildlife, human activity). The difficulty with the selection of appropriate indicators may, in most cases, arise from the variety of habitats and local climatic conditions which shape their functioning. All the observed changes - effects in habitats - result from many causes and the evaluation of separate effects of individual drivers is not an easy task. It is thus necessary to develop such indicators that predict habitat sensitivity to climate change in a most direct way. The indicators are widely sought for which may be taken as surrogate for other attributes of habitats and representative of the summary effects of climate change in ecosystems and, at the same time, be simple and easy to apply. The geobotanical indicators were already discussed by Kloss 2010 (External expertise, Progress Report I) and Ostrowska 2010 (External expertise Progress Report I). The indicators in question, albeit representing the relationships between species and habitats, are seemingly not specific enough to evaluate local effects in wetland habitats and, in particular, for estimating short and longterm effects of human activities in wetland ecosystems under pressure of changing climatic factors. In our study in wetlands of the BNP, in order to develop the integrated indicators of climate change induced habitat changes, we assumed the following approach focussing on the properties of soils and plant communities: 1. Survey of the wetland environment in the BNP. 2. Selecting characteristics of the soil environment and plant communities which are most sensitive to climate change driven pressures and determining variability scales for every characteristics within the area examined. 3. Identification of properties which are most closely interrelated with other features examined, based on statistical correlations. 4. Evaluation of climate change driven variability of selected properties. [3]

5 5. Evaluation of changes of selected features with respect to their indicatory value for the assessment of climate change driven changes in the remaining properties of soils and vegetation. 6. Prognosis of changes in soils and plant communities in the Biebrza National Park (Biebrza River valley) based on reconstruction of the past and forecast of the future local climate conditions. 2. Survey of the wetland environment Wetland habitats in the Biebrza National Park have been studied by many authors since the half of the 20 th century and even earlier (Ostrowska 2010 Expertise Progess Report I). Negative changes in the environment, and especially in soil properties and typical plant communities in the Biebrza valley, were found to be due to mainly human activities such as drainage, peat excavation and agriculture. Numerous authors including Okruszko (in Ostrowska 2010 External expertise, Progress Report I) reported that in the drained mires, the enhancement of peat decay process is expressed by the decrease of peat mass thickness by about 1.03 cm annually, i.e. in the loss of about 15 t/ha/year of peat. At the same time, about 5-7 t of carbon and about 674 kg of nitrogen are released to the environment. Such an enhancement of soil organic matter mineralization could also result from the advancing climate warming. The authors of these studies emphasized that the main causes underlying changes in wetland habitats were qualitative and quantitative disturbances in water circulation, in particular in the amount and dynamics of water flow. Prolonged periods of drought resulted in the excessive drying of the surface peat layer, peat mineralization and in further changes that could be seen in plant communities. Taking into account the previous results we analyzed the present status of local habitats in the BNP focusing on the composition and structure of local phytocoenoses with respect to their sensitivity to climate change and utility for building indicators to monitor further habitat changes (Kucharski 2010 External expertise Progress Report I) and Kloss 2010 (External expertise Progress Report I).The results of these studies suggest that habitat changes in the BNP accumulating over time may be to a great extent assigned to climate change. These changes can be seen, among others, In the blurring of contour lines in the natural transversal distribution of plant communities, in particular in the non- or scarcely flooded portions of the Biebrza valley as well as in the encroachment of invasive plant species which, in general, have a higher nutrient demand than the local native species. As a measure of the extent of changes in the vegetation cover the mean values of the Ellenberg s ecological numbers have been frequently used. It was shown that these numbers may be significantly correlated with various parameters describing growth conditions of species and plant communities, as e.g. mean values of the light index show a high degree of correlation with the relative light intensity at the forest floor, while the mean values of moisture index correlate with the average groundwater level and the average annual soil moisture. However, it is also stressed that these ecological indicators are arbitrary and general. Comparison of phytosociological surveys made in the Biebrza valley within the time span of about 40 years shows that the evaluation with the Ellenberg mean moisture and site fertility indices allows for the assessment of changes in hydrological and trophic conditions of habitats. Over the four last decades there was a decrease in This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [4]

6 soil moisture with the simultaneous increase in soil fertility, however, the author stressed that such inferences have limitations since Ellenberg numbers are based upon subjective choice of available observations within a given area (Kloss 2010 External Expertise). In this study, four transects (Barwik, Trzyrzeczki, Grzędy and Szuszalewo) were delineated cross cutting habitats representative of the soil and hydrological conditions of the three Biebrza River basins. Along these transects 18 study plots were established where soil and plant material sampling was conducted for chemical analyses. Altogether 144 soil samples and 120 plant samples were taken, out of which 100 plant samples were analyzed. Species composition was inventoried at all the study plots by making at least 6 phytosociological releves. The detailed description of soil and plant sampling methods as well as of chemical analyses of results was reported earlier (Progress Report I and II). Along all the four transects soil types were identified (Borzyszkowski 2011 External Expertise Progress Report III), Fig. 1 and there were determined the contents of carbon, nitrogen and the sum of elements migrating to soil solution. These results were graphically visualized in the maps showing a clear relationship between the soil type and the soil properties examined (Kuśmierz 2011 External Expertise, Progress Report III) and Bidłasik 2011 (External Expertise, Progress Report III), Figs Particularly evident are the relationships between the carbon and nitrogen contents and between the carbon content and the stock of plant nutrients in soils solutions. At the same time, the maps of plant community distribution were drawn along all the transects examined to illustrate the status of ecotones (Bidłasik 2011, External Expertise, Progress Report III), Fig. 6. [5]

7 Figure 1. Soil maps a) b) c) d) This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [6]

8 Figure 2. Maps of total organic carbon content in soil a) b) c) d) [7]

9 Figure 3. Maps of total nitrogen content in soil a) b) c) d) This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [8]

10 Figure 4. Maps of mineral nitrogen content in soil a) b) c) d) [9]

11 Figure 5. Maps of sum of elements in soil solution a) b) c) d) This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [10]

12 Figure 6. Maps of plant community a) b) c) d) [11]

13 3. Selecting characteristics of the soil environment and plant communities which are most sensitive to climate change driven pressures and determining variability scales for every attribute within the area examined. In the BNP there dominate peat soils of various degrees of mineralization. The carbon content constitutes a basic feature of these soils and fluctuates from 50 and more to 40% in natural peats, to 40-30% in decaying/moorshing peats, to 30-20% in moorshy peats and to less than 20% in moorsh soils. Along the transects examined there occur also typical podsol and brown forest soils developed from mineral materials. Numerous authors report that soil carbon may be regarded as a soil characteristics most sensitive to climate changes (Ostrowska 2010 External expertise Progress Report I) what was also found in the earlier works of the authors of this Project (Ostrowska 2006, Ostrowska and Porębska 2011). The most climate change sensitive features of plant communities are shifts of ecotones, shifts in species composition and community structure, and an increase in the share of invasive species. 4. Selection of habitat characteristics most sensitive to climate change soils The effects of climate change in the soil environment have been widely discussed, in particular the effect of climate warming on the intensification of soil organic matter mineralization (Ostrowska 2010, Progress Report I). In the case of organic soils it is the carbon accumulation that provides a most sensitive characteristics of the effects of climate changes and a good indicator of climate change induced changes. In the BNP there dominate organic soils developed from peat which were found to contain various amounts of carbon, what may testify to a advancing loss of soil carbon over time. To assess the indicatory strength of the soil carbon content, the correlational and functional relationships were statistically determined between this content and the remaining soil attributes such as SOM, SON, DON, CEC, sum of exchangeable cations, SWC, MWHC, FWC,BD (Gozdowski 2011 External expertise, Progress Report III). These relationships were analyzed in four data sets divided on the basis of the value of soil carbon content (carbon content compartments), taking into account the variability of this value between the soils of the BNP. Despite the relatively high values of Standard Deviations calculated for respective soil properties, in most cases there were found a significant relationships between the carbon content and the other soil features (Table 1 and 2). Table 1. Mean values and standard deviations (mean±sd) of the examined variables for 4 groups of SOC content in soils. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [12]

14 Groups C (%) SOC (%) SON (%) SOM (%) DOC (mg/kg) DON (mg/kg) CEC (me/kg) Sum (me/kg) a± a± a± a± a± a± a± b± b± b± ab± a± a± a± c± c± c± bc± b± b± b± d± d± d± c± b± b± b±21.27 All means of SOC, SON and SOM are significantly different between the groups. The lowest mean values of these three variables were observed for group and the highest for group The differences for DON, CEC and Sum were significantly different between the groups 0.1-3; and the two other groups i.e ; Table 2. Analyses were performed on limited (n=44) number of observations i.e. the datasets with additional variables. Groups C (%) BD (g/cm3) SWC (%) MWHC (%) ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±0.53 all 0.76± ± ± ± ± ±0.9 Close relationships were found between all these properties what is evidenced by the high values of correlation coefficients, though the most significant correlation was determined between the soil carbon content and the remaining soil properties. This was found when correlating both all the data sets and the data from the group of carbon content less than 20%. Weaker correlations were noted at higher carbon contents (Table 3). Table 3. Pearson s correlation coefficients between eatch other properties of soils (n=100) (significant correlations at P<0.05 probability level are in bold) Data for all groups SOC SON SOM DOC DON CEC Sum SOC SON SOM DOC DON CEC Sum groups: SOC SON SOM DOC DON CEC Sum SOC SON SOM DOC DON CEC Sum groups: SOC SON SOM DOC DON CEC Sum SOC FWC (%) SOC (%) SON (%) [13]

15 SON SOM DOC DON CEC Sum Almost all correlations between examined variables for all data set were positive and significant. The strongest correlations were observed between SOM and SOC, correlation coefficient for all data set was equal to In Table 4, the relationships are presented between the soil carbon content and soil water properties. Table 4. Pearson s correlation coefficients between examined variables of data (significant correlations at P<0.05 probability level are in bold). BD SWC MWHC FWC SOC SON SOM DOC DON Sum CEC BD SWC MWHC FWC SOC SON SOM DOC DON Sum Sum-cec CEC Almost all correlation were significant and most of them positive. A more detailed description of the relationships between soil properties is provided on the basis of regression equations. The values of determination coefficients (R 2 ) >0.7 were characteristic of the relationships between the contents of carbon, organic matter and nitrogen. On the other hand, the relationships between the remaining soil properties were defined by determination coefficients (R 2 ) = , which were also significant (Fig.7). The relationships between the soil water and other soil properties were evaluated with the use of non-linear regression models. In each case, the values of determination coefficients were high - ( R 2 ) >0.7 or even > 0.9. Special attention shall be given to the significant relationships between the sum of elements in soil solutions and the actual and potential water contents (Fig.8). Figure 7. Linear regression between SOC and other properties of soils. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [14]

16 Sum (me/kg) Sum (me/kg) CEC (me/kg) Sum (me/kg) SON (%) DON (mg/kg) DOC (mg/kg) DON (mg/kg) SOM (%) SOC (%) y = 1,7244x + 1,1512 R 2 = 0, y = 0,5525x + 0,5046 R 2 = 0, SOC (%) SOM (%) y = 38,128x + 113,97 R 2 = 0, y = 44,978x + 13,804 R 2 = 0, SOC (%) 0 0 0,5 1 1,5 2 2,5 3 3,5 SON (%) y = 0,0457x + 0,1826 3,5 R 2 = 0,7267 3,0 2,5 2,0 1,5 1,0 0,5 0, SOC (%) y = 0,0398x + 30,477 R 2 = 0, DOC (mg/kg) y = 12,227x + 113, R 2 = 0, SOC (%) y = 0,8213x + 9, R 2 = 0, SOC (%) y = 0,0461x + 10,192 R 2 = 0, y = 0,4762x + 8,6462 R 2 = 0, CEC (%) SOM (%) Figure 8. Non-linear regression functions were used between SOC and other properties of soils. [15]

17 FWC (%) MWHC (%) MWHC (%) SWC (%) MWHC (%) BD (g/cm3) BD (g/cm3) MWHC (%) BD (g/cm3) BD (g/cm3) 1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0 y = -0,00001x 3 + 0,00096x 2-0,06151x + 1,54831 R 2 = 0, ,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0 y = -0,00003x 3 + 0,00295x 2-0,10717x + 1,53368 R 2 = 0, SOM (%) SOC (%) 1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0 y = -5E-11x 3 + 5E-07x 2-0,0016x + 1,5466 R 2 = 0, DOC (mg/kg) y = 0,0011x 3-0,1185x 2 + 4,0555x + 33, R 2 = 0, SOC (%) y = 10,055Ln(x) + 32, R 2 = 0, SOM (%) 1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0 y = -6E-09x 3 + 1E-05x 2-0,0079x + 1,5975 R 2 = 0, CEC (me/kg) y = 13,745Ln(x) - 7,3177 R 2 = 0, y = 13,731Ln(x) + 8,7846 R 2 = 0, CEC (me/kg) Sum (me/kg) y = 10,198Ln(x) + 11,84 30 R 2 = 0, Sum (me/kg) y = 11,81Ln(x) + 30,253 R 2 = 0, Sum (me/kg) A detailed analysis was made of the composition of both CEC and the element sum in the soil solution as well as of the relationships between the content exchangeable cations and that of dissolved cations. The element sum and the ion composition in soil solutions on the one hand, and the element sum and its ion composition in the soil sorption complex on the other, are of decisive importance, directly This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [16]

18 and indirectly, for the nutrient availability to plants. The sum of elements dissolved increases with the increase in the soil carbon content (Table 5). Calcium next to N-NH 4 and Mg have largest shares in the element sum (Table 6). Table 5. Mean values (me/kg) and standard deviations (mean ± SD) of the examined variables for SOC content in the soils. Groups C (%) Cl SO 4 N-NO 3 N-NH 4 Ca Mg Na a± a± a± a± a± a± a± ' 0.43ab± ab± a± a± a± a± a± bc± bc± a± b± b± b± b± c± c± a± b± b± b± b±1.54 all 1.47± ± ± ± ± ± ±1.39 Groups C (%) K Fe Al Mn Cu Zn Sum a± a± a± a± a± a± a± ' 0.14a± a± a± a± a± a± a± ab± a± a± a± a± a± b± b± a± a± a± a± a± b±21.27 all 0.72± ± ± ± ± ± ±23.45 Variability of the properties was very high because in many cases values of standard deviations (SD) were higher than mean values. Table 6. The sequence of importance (shares) of the ions in soils solution for all data set based on standardized partial regression coefficients. SE=0.184 R 2 =0.999 standardized b i b i p Intercept (a) Cl <0.001 SO <0.001 N-NO <0.001 N-NH <0.001 Ca-ss <0.001 Mg-ss <0.001 Na-ss <0.001 K-ss <0.001 Fe <0.001 Al-ss <0.001 The sequence is following: Ca-ss>N-NH4>Fe>Mg-ss>SO4>Cl>K-ss>Na-ss>N-NO3>Al-ss The value of the exchangeable cation sum increases with the increase in carbon content, however, at the content of SOC > 36%, differences are not significant what is evidenced by a high values of Standard Deviation (Table 7). [17]

19 Table 7. Mean values (me/kg) and standard deviations (mean ± SD) of the examined variables for SOC content in soils. Groups C (%) Al-cec H Ca-cec Mg-cec K-cec Na-cec CEC a± a± a± a± a± a± a± a± a± a± a± ab± a± a± a± ab± b± b± bc± b± b± a± b± b± b± c± b± b±341.8 all 8.7± ± ± ± ± ± ±350.3 Homogenous groups of means (means between the difference is not significant) based on Tukey s procedure of multiple comparisons were marked by the same letters. If the means do not have the same letter, the difference is statistically significant. The value of the exchangeable cation sum increases with the increase in carbon content, however, at the content of SOC > 36%, differences are not significant what is evidenced by a high values of Standard Deviation (Table 8). Table 8. The sequence of importance of the ions for all data set SE=2.71 R 2 =0.999 standardized b i b i p intercept Al-cec <0.001 H <0.001 Ca-cec <0.001 Mg-cec <0.001 Na-cec The sequence of importance of the ions for all data set based on standardized partial regression coefficients is following: Ca > Mg > H > Al > Na In the soil sorption complex, as in soil solutions, there dominate Ca followed by Mg (Table 8). High values of correlation coefficients were determined for the correlation between exchangeable ion forms (in CEC), including: Ca, Mg, Na, K and Al, and their forms dissolved in the soil solution, in various carbon content compartments (Table 9). These relationships were corroborated by calculated determination coefficients R 2 of linear regression which were in the majority of cases > 0.6 (Fig.9). The exchangeable elements constitute a supplementing stock of elements released to soil solution as they migrate away. Both the dissolved and exchangeable element forms are closely correlated and both play regulatory role in the nutrient availability to plants as well as in the outflow of mobile forms to groundwater. Table 9. Pearson s correlation coefficients between examined variables for each group of data and all data together (significant correlations at P<0.05 probability level are in bold) Groups C (%) Ca-ss and Ca-cec Mg-ss and Mg-cec Na-ss and Na-cec K-ss and K-cec Al-ss and Al-cec This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [18]

20 Al-cec (me/kg) Na-cec (me/kg) K-cec (me/kg) Ca-cec (me/kg) Mg-cec (me/kg) all Almost all correlation between ss and cec contents of elements were significant and positive. Only in group the relationships for Ca, Mg and K were weak. The strongest correlations were obtained for K (correlation coefficient for all data set was equal to 0.94). For groups and correlations were stronger than in other two groups. Figure 9. Linear regression analysis for relation between cations y = 18,902x + 97, R 2 = 0, Ca-ss (me/kg) y = 8,6549x + 6, R 2 = 0, Mg-ss (me/kg) 14 y = 1,3434x + 1, R 2 = 0, Na-ss (me/kg) 25 y = 2,4779x + 1, R 2 = 0, K-ss (me/kg) y = 14,563x + 0,2997 R 2 = 0, ,0 1,0 2,0 3,0 4,0 5,0 Al-ss (me/kg) 5. Evaluation of sensitivity of selected habitat properties to climate change soils It goes without saying that the soil building material has a decisive importance with regard to soil properties. However, these properties are additionally modified owing to the action of other factors. The variability of mineral soils is to a great extent dependent on the parent material and is less prone [19]

21 to the activity of external factors, at least in the short term considerations. The organic soils, build mainly by the organic matter under definite site, climatic and land use conditions, may be largely homogeneous. Changes in these conditions (e.g. temperature rise, decrease in precipitation, intensification of agriculture) bring about quantitative and qualitative destabilisation of organic matter. Progressing climate warming impairs the hydrological regime followed by disturbances in the production and accumulation of organic matter and its decomposition, shifting the balance towards the latter. The loss of organic matter is accompanied by the release of CO 2 and the migration of nutrients, and of nitrogen in particular, to the soil solution. In the case of soils in the BNP, it was found that their drainage may lead to the release of about 5-7 t of C or t of CO 2 from the upper soil layer. Simultaneously, around 674 kg of mineral nitrogen migrate to the groundwater, and the organic matter decomposition in the deeper layer of peat deposits is deficient. This leads to changes in the soil properties. Carbon constitutes the basic element building the soil organic matter (SOM) and may provide a quantitative measure of changes which occur in organic soils, and in particular, of the climate change induced changes in carbon circulation within the system: assimilation to organic matter and release to the atmosphere in the process of OM decomposition. The latter was a subject of many investigations and the results were summarized in the earlier work [Ostrowska 2010 External Expertise]. 6. Evaluation of the soil carbon content as indicator of climate change induced changes in wetland soils in the BNP In order to determine the sensitivity of the above indicator for assessing the scope of changes in various other soil properties, the changes were simulated in the soil carbon content in parallel to the changes in other soil properties. The relationships were determined as relative values comprised in the range from 0 to 100%, where the lowest values of carbon content and of the remaining soil parameters were assumed to be 0% while the highest values of carbon content and other parameters were assumed to be 100% (Table 10). Table 10. Relative values of examined properties from 0 to 100% (by 5%) and corresponding estimated real values of these properties. SOC SON SOM DOC DON Sum CEC MHWC relative real relative real relative real relative real relative real relative real relative real relative measured % % % % % % % mg/kg % mg/kg % me/kg % me/kg % % This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [20]

22 Relative value of SOM (%) SOC SON SOM DOC DON Sum CEC MHWC relative real relative real relative real relative real relative real relative real relative real relative measured Both linear and non-linear regression analyses were used for assessing the relationships between the values investigated. Generally, the decrease in carbon content is associated with the decrease in the values of other parameters, with the exception for bulk density (BD), the values whereof increased. A highly significant correlation was observed between the contents of soil carbon and that of SOM so that for 1% of carbon loss (in the range 1-100%) there was 1.028% loss in SOM (Fig.10). Figure 10. Linear regression analysis of relative values y = 1,028x Relative value of SOC (%) Parameter change on 1% of SOC On the other hand, the rate of total nitrogen loss varied depending upon the percent decrease in carbon content. In the range of the carbon content relative values between 100 and 70%, the decrease in carbon by 1% was associated with 1.5% decrease in nitrogen content. In the range of carbon content decrease from 30 to 1% the loss in carbon by 1% was accompanied by % decrease in the total nitrogen content (Fig. 11). Figure 11. Non-linear regression analysis of relative values. [21]

23 Relative value of DON (%) Relative value of SON (%) y = -0,0003x 3 + 0,0229x 2 + 0,6628x Relative value of SOC (%) Parameter change on 1% of SOC Thus it can be estimated that the first stage of peat decay (moorshing), when carbon content decreases from about 50 to 30%, is associated with a considerable migration of nitrogen to the soiland groundwater. The rate of decrease in dissolved nitrogen DON is similar to the rate of total nitrogen migration although it was observed to raise slightly with the decrease in carbon content. (Fig. 12). Figure 12. Non-linear regression analysis of relative values y = -0,0001x 3 + 0,0042x 2 + 0,8246x Relative value of SOC (%) Parameter change on 1% of SOC Likewise, along with the decrease in carbon content there is a decrease in the values of other investigated parameters (Fig ), including the maximal water capacity (MWHC) (Fig. 16). Whereas the rate of the loss of soluble carbon forms (DOC), elements sums and MWHC increases with the decrease in the value of TOC (Table 11-12). Figure 13. Non-linear regression analysis of relative values. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [22]

24 Relative value of CEC (%) Relative value of SUM (%) Relative value of DOC (%) y = 0,0002x 3-0,0269x 2 + 1,2028x Relative value of SOC (%) Parameter change on 1% of SOC Figure 14. Non-linear regression analysis of relative values y = -0,00008x 3-0,00034x 2 + 1,07835x Relative value of SOC (%) Parameter change on 1% of SOC Figure 15. Non-linear regression analysis of relative values y = -0,0002x 3 + 0,0139x 2 + 0,8271x Relative value of SOC (%) Parameter change on 1% of SOC Figure 16. Non-linear regression analysis of relative values. [23]

25 Relative value of MWHC (%) y = -0,022x 2 + 2,784x Relative value of SOC (%) Parameter change on 1% of SOC Table 11. Changes of other properties depending on relative SOC values in range from ) to 50%. SOC (%) SON ΔSON SOM ΔSOM DON ΔDON DOC ΔDOC CEC ΔCEC SUM ΔSUM BD ΔBD MWHC ΔMWHC Table 12. Changes of other properties depending on relative SOC values in range from 20 to 30%. SOC (%) SON (%) ΔSON (%) SOM (%) ΔSOM (%) DON (%) ΔDON (%) DOC (%) ΔDOC (%) CEC (%) ΔCEC (%) SUM (%) ΔSUM (%) BD (%) ΔBD (%) MWHC (%) ΔMWHC (%) This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [24]

26 The loss of soil carbon content does not occur systematically over time, since it is conditioned by, among others, the dynamics of climate change phenomena (disturbances in water circulation, rises in average temperatures, etc). The loss of carbon from the soil shall be considered as an indicator of habitat changes which occur over longer time periods, taking at least several years. As a result of SOM mineralization under conditions of wetland soils in the BNP there is a significant migration of nitrogen and other soil elements to the groundwater. This process may be indicated though the determination of various nitrogen forms in the soil as well as of the element sums in the soil solution. The above parameters are both significantly correlated (r >0.7) with the remaining properties of these soils, and both may be considered as indicators of the short term habitat changes. 7. Plant species and communities as integrated indicators of habitat changes As was already mentioned, plant species, and plant communities in particular, are widely used for predicting habitat quality and the effects of various pressures (Roo-Zielińska et al 2007, Kloss, Kucharski, External Expertises). Plant communities are considered to be a more effective integrated indicators of habitat conditions than just single species since their ecological amplitudes are much narrower as those of the individual plant species. The value of various plant indicators, including the mean Ellenberg indicator values, was also discussed within the context of predicting other environmental variables, especially the soil parameters. It was shown that e.g. the mean Ellenberg values (for respective phytocoenoses) have limitations as habitat indicators for their applicability has been proven for mostly stable phytocoenotic conditions while in the disturbed communities with untypical species composition they are much less reliable. Thus it can be expected that they constitute a weaker predictors of the environmental conditions in disturbed or unstable habitats (Dzwonko 2001). Shifts in species composition, on the other hand, under natural or close to natural habitat conditions, may indicate changes in habitat conditions and e.g. predict local environmental disturbances. Wetland habitats in the Biebrza valley vary depending not only upon hydrological and soil conditions but also upon historical (past management) and climatic factors. Climate change induced habitat changes result in shifts of ranges of respective natural plant communities and affect the local species composition and phytocoenose structure. Climate warming, in addition to other factors, seems to be of special importance due to its proven effect in wetland soil degradation. The obvious consequence of the latter is accelerated SOM mineralization (soil moorshing peat decay) which proceeds in two phases: first it increases (quasi eutrophication) and later decreases the pool of nutrients available to plants. The increase in the amount of available nutrients may result in the expansion of species which have a high nutrient demand and are not necessarily natural to respective communities (invasive species). The effect of quasi eutrophication in organic soils was studied especially in the Barwik transect. Species composition was investigated (according to the method by Braun-Blanquet 1964) in natural plant communities (habitats) along this transect to determine the sequence of domination of plants having high nutrient demand. The respective communities range from the moist tall sedge meadows [25]

27 of Magnocaricion with such species as Carex gracilis, C. riparia, C. elata, C. acutiformis, C. paradoxa and Phalaris arundinacea, to the alder wood with black currant Ribeso nigri-alnetum where in the rich herbaceous layer there dominate Ribes nigrum, Carex riparia, Galium uliginosum, Thelypteris palustris, Phragmites australis, Athyrium filix-femina, Padus avium, Caltha palustris with lesser proportion of Urtica dioica, Impatiens noli-tangere (Table 13), to the drying riparian alder-ash wood Fraxino-Alnetum where there dominate Impatiens noli-tangere, Geranium robertianum, Oxalis acetosella and Urtica dioica with lesser share of Geum rivale, Anemone nemorosa and Rubus idaeus (Table 14), to the transitory community between the drying Fraxino-Alnetum and oak-hornbeam wood Tilio-Carpinetum (phase of Corylo-Piceetum) with the dominating Impatiens noli-tangere, Galeobdolon luteum, Corylus avellana, Stellaria holostea, Anemone nemorosa and Aegopodium podagraria (Table 15). Table 13. Barwik - Black currant - alder wood Ribeso nigri-alnetum Serial number of releve Fidelity Releve surface (m 2 ) class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Ch. Cl. Alnetea glutinosae Ribes nigrum b III 66 Ribes nigrum c IV 564 Salix pentandra b + + II 3 Thelypteris palustris V 735 Lycopus europaeus V 20 Solanum dulcamara III 16 Ch. Cl. Querco-Fagetea 0 Impatiens noli-tangere V 350 Chrysosplenium alternifolium IV 68 Padus avium b V 973 Padus avium c IV 1200 Plagiomnium undulatum + + II 3 Poa nemoralis III 345 Ch. Cl. Molinio-Arrhenatheretea 0 Caltha palustris V 723 Galium uliginosum II 656 Poa trivialis IV 469 Lychnis flos-cuculi IV 8 Lysimachia vulgaris V 71 Ranunculus repens IV 130 Filipendula ulmaria V 193 Scirpus sylvaticus 1 1 II 125 Angelica sylvestris + + II 3 Ch. Cl. Phragmitetea 0 Carex riparia V 4969 Galium palustre V 689 Phragmites australis V 878 Lysimachia thyrsiflora 1 + II 64 Scutellaria galericulata IV 8 Cicuta virosa + + II 3 Accomp.species 0 This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [26]

28 Serial number of releve Fidelity Releve surface (m 2 ) class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Alnus glutinosa a V 1688 Alnus glutinosa b 4 3 II 1250 Alnus glutinosa c + + II 3 Betula pubescens a IV 1656 Sorbus aucuparia a 1 I 63 Sorbus aucuparia b II 65 Sorbus aucuparia c II 4 Viburnum opulus b + 1 II 64 Viburnum opulus c II 221 Urtica dioica V 70 Athyrium filix-femina IV 346 Epilobium palustre + + II 3 Geum rivale IV 6 Rubus idaeus II 4 Dryopteris carthusiana III 5 Humulus lupulus + + II 3 Mnium rostratum V 133 Plagiomnium affine + + II 3 Mnium punctatum + + II 3 Sporadic species in releve No: 1-Corylus avellana b +, Deschampsia caespitosa +, Cirsium rivulare +, Scutellaria galericulata +, 2-Betula pubescens c +, Geranium robertianum +, Brachytecium rivulare +, B. rutabulum +, 3-Festuca gigantea +, 4-Rubus saxatilis+, Peucedanum palustre+, Maianthemum bifolium+, 5-Salix cinerea b i c+, Paris quadrifolia +, 6-Glyceria notata +, 8-Myosotis palustris+, B. pubescens b +. Table 14. Barwik - Drying riparian alder-ash wood Fraxino-Alnetum Serial number of releve Fidelity Releve surface (m 2 ) class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Ch. Cl. Alnetea glutinosae Ribes nigrum b III 573 Ribes nigrum c III 610 Thelypteris palustris + + II 3 Ch. Cl. Querco-Fagetea Impatiens noli-tangere V 5143 Chrysosplenium alternifolium III 76 Padus avium b V 1679 Padus avium c V 397 Stellaria nemorum III 821 Euonymus europaea III 6 Galeobdolon luteum III 501 Anemone nemorosa IV 396 Milium effusum III 254 Coryllus avellana b III 789 Ch. Cl. Artemisietea vulgaris Urtica dioica V 1250 [27]

29 Serial number of releve Fidelity Releve surface (m 2 ) class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Geranium robertianum V 2000 Galium aparine V 219 Geum urbanum III 323 Myosoton aquaticum 2 I 250 Anthriscus sylvestris III 144 Galeopsis pubescens III 146 Rumex obtusifolius IV 77 Accomp.species Alnus glutinosa a V 1930 Betula pubescens a V 659 Sorbus aucuparia b III 146 Sorbus aucuparia c III 74 Picea abies a III 787 Sambucus nigra b III 4 Sambucus nigra c III 6 Viburnum opulus c + + II 3 Rubus saxatilis + + II 3 Rubus idaeus V 397 Athyrium filix-femina V 80 Dryopteris carthusiana + + II 3 Geum rivale III 394 Humulus lupulus III 4 Moechringia trinervia IV 256 Stellaria media + + II 3 Oxalis acetosella V 3357 Cicuta virosa III 74 Lysimachia vulgaris III 6 Poa trivialis + + II 3 Crepis paludosa V 9 Mnium rostratum III 6 Plagiomnium affine + + II 3 Brachytecium rivulare + + II 3 Sporadic species in releve No: 9-Galium palustre 1, Corylus avellana 1, Aegopodium podagraria +, Equisetum sylvaticum +, 10-Scrophularia nodosa +, Taraxacum officinale +, Rumex acetosa +, Chelidonium majus +, 11- Stellaria holostea +, Polygonum odoratum +, 12-Peucedanum palustre 1, Picea abies b +, 13-Alnus glutinosa +, Populus tremula c +, Maianthemum bifolium +, 15-Quercus robur c +, Poa nemoralis +, Filipendula ulmaria +, Mentha longifolia +, Alliaria petiolata +, Glechoma hederacea +, Convallaria majalis +, Viola riviniana +, Mycelis muralis +. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [28]

30 Table 15. Barwik - Transition from Fraxino-Alnetum to oak-hornbeam wood Tilio-Carpinetum (Corylo-Piceetum) Serial number of releve Releve surface (m 2 ) Fidelity class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Ch. Cl. Alnetea glutinosae Ribes nigrum c III 38 Thelypteris palustris II 3 Ch. Cl. Querco-Fagetea Impatiens noli-tangere V 7450 Chrysosplenium alternifolium IV 171 Padus avium b V 313 Padus avium c IV 138 Quercus robur a I 35 Aegopodium podagraria II 434 Stellaria nemorum I 2 Carex remota I 2 Galeobdolon luteum V 2450 Anemone nemorosa V 1401 Paris quadrifolia + + I 1 Hepatica nobilis I 67 Milium effusum V 9 Coryllus avellana b V 3251 Coryllus avellana c IV 7 Stellaria holostea IV 819 Ch. Cl. Artemisietea vulgaris Urtica dioica IV 73 Geranium robertianum IV 39 Galium aparine II 3 Accomp. Species Alnus glutinosa a V 1668 Betula pubescens a V 1169 [29]

31 Serial number of releve Releve surface (m 2 ) Fidelity class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Betula pubescens c 1 + I 34 Picea abies a V 1085 Betula pendula a 2 + I 117 Viburnum opulus c + + I 1 Sorbus aucuparia c I 2 Athyrium filix-femina V 140 Lapsana communis IV 39 Geum rivale II 3 Rubus saxatilis I 2 Rubus idaeus IV 157 Dryopteris carthusiana V 74 Maianthemum bifolium IV 40 Oxalis acetosella V 3150 Rubus caesius II 3 Cicuta virosa II 37 Gymnocarpium dryopteris II 3 Mnium rostratum II 37 Plagiomnium affine II 35 Plagiomnium undulatum + 1 I 34 Brachytecium rivulare II 35 Sporadic species in releve No: 16-Convallaria majalis +, 17-Humulus lupulus +, 20-Quercus robur c +,21-Scrophularia nodosa +, Acer platanoides c +, Populus tremula c +, Polygonatum multiflorum +,24-Alnus glutinosa c +, Ribes nigrum b +, Euonymus europaea +, Galium uliginosum +, Poa trivialis +, Lysimachia vulgaris +, Angelica sylvestris +, Galium palustre b +, 26-Betula pubescens b +, 28-Scutellaria galericulata +,29-Picea abies b +, 30-Dryopteris filix-mas +. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [30]

32 The above communities were identified along the transversal axis of the valley marking the trend of decreasing ground water table and the increasing distance from the river bed marking the reach of river flooding, while the oligotrophic wing of the Barwik transect constitutes a species poor community located on mineral soils, in the mixed forest of Calamagrostio arundinaceae-pinetum with Frangula alnus, Festuca ovina, Vaccinium myrtillus, Melampyrum pratense and Pleurozium schreberii and Dicranum undulatum in the moss layer (Table 16). Table 16. Barwik Mixed forest Calamagrostio arundinaceae-pinetum (Piceetum) Serial number of releve Releve surface (m2) Coefficient Fidelity a-tree layer, b-shrub of sp.cover class layer, c-herbaceous layer, degree d-moss layer Ch. Cl. Vaccinio-Piceetea Betula pubescens a IV 502 Betula pubescens c II 3 Betula pubescens b III 55 Picea abies a 3 I 375 Picea abies b 2 + I 176 Pinus sylvestris a IV 5250 Vaccinium myrtillus IV 703 Vaccinium vitis-idaea III 153 Trientalis europaea II 101 Melampyrum pratense V 1952 Pleurozium schreberi V 3875 Ch. Cl. Querco-Fagetea Quercus robur b IV 329 Quercus robur c IV 106 Corylus avellana b 3 + I 376 Corylus avellana c 1 + I 51 Accomp. species Betula pendula a + + I 2 Sorbus aucuparia b + + I 2 Sorbus aucuparia c III 54 Frangula alnus b V 1229 Frangula alnus c IV 1028 Rubus plicatus 2 2 I 350 Luzula pilosa III 104 Maianthemum bifolium 2 + I 176 Oxalis acetosella III 802 Calamagrostis arundinacea III 63 Convallaria majalis IV 57 Solidago virgaurea + + I 2 Festuca ovina V 1177 Anthoxanthum odoratum III 228 Rubus laciniatus + 1 I 51 Juniperus communis b III 5 Juniperus communis c II 3 Agrostis vulgaris 1 1 I 100 Hieracium pilosella II 3 [31]

33 Serial number of releve Releve surface (m2) Coefficient Fidelity a-tree layer, b-shrub of sp.cover class layer, c-herbaceous layer, degree d-moss layer Carex pilulifera II 4 Melampyrum nemorosum 2 I 175 Dryopteris carthusiana II 4 Rumex acetosella II 4 Dicranum undulatum V 1150 Sporadic species in releve No: 31-Anemone nemorosa +, Stellaria holostea +, Populus tremula a +, Mycelis muralis +, Pteridium aquilinum +, Galium aparine +, 32-Polygonatum multiflorum +, Veronica officinalis +, 33-Dryopteris filix mas +, Acer pseudoplatanus b +, Rumex acetosa +, Stellaria graminea +, 34-Padus avium b i c +, 35-Calluna vulgaris +, 36-Pinus sylvestris c +, 37-Festuca heterophylla +, 39-Viburnum opulus +, Rubus idaeus +. A characteristic feature of the three wood communities on drying organic soils is the diminishing share of moisture-depending species of the Class Alnetea glutinosae and the increasing share of species of the Class Querco-Fagetea. At the same time, there is an increase in abundance of the socalled nitrophilous species of the Class Artemisietea which have a higher nutrient demand. The latter group includes such plants as Urtica dioica, Geranium robertianum, Galium aparine, Geum urbanum, Anthriscus silvestris, Galeopsis pubescens and Rumex obtusifolius. In the drying riparian alder-ash wood, the above species occurred with high fidelity classes: III-V and high coefficients of species coverage (Table 14). It is also noteworthy to add that the drying patches of riparian alder-ash wood are build by numerous group of accompanying species (Fig. 6a). The increase in numbers and abundance of nitrophilous and accompanying species is an indicator of disturbances in respective habitats resulting from changes in the soil environment. A similar increase in nitrophilous species abundance was also found in the drying ash-elm wood Ficario- Ulmetum on organic soils along the Trzyrzeczki transect (Table 17 and 18, Fig. 6c). Table 17. Trzyrzeczki - Drying spruce -alder wood in transition to oak-hornbeam forest Serial number of releve Fidelity Releve surface m class a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Ch. Cl. Vaccinio-Picetea Coefficient of sp.cover degree Picea abies a V 5500 Picea abies b Picea abies c Sorbus aucuparia a + + Sorbus aucuparia b Sorbus aucuparia c V 172 Vaccinium myrtillus V 172 Lycopodium annotinum + + II 3 Luzula sylvatica III 5 Ch. Cl. Querco-Fagetea 0 Mnium undulatum V 418 This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [32]

34 Serial number of releve Fidelity Releve surface m class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Lonicera xylosteum b Lonicera xylosteum c V 173 Quercus robur c III 5 Paris quadrifolia IV 7 Viola reichenbachiana III 5 Carex sylvatica + 1 II 85 Ulmus glabra a Ulmus glabra b Ulmus glabra c + + II 3 Fraxinus excelsior c + + II 3 Euonymus europea IV 7 Corylus avellana c + + II 3 Anemone nemorosa + + II 3 Milium effusum III 5 Stellaria nemorum + + II 3 Ch. Cl. Molinio-Arrhenatheretea Caltha palustris III 87 Filipendula ulmaria III 5 Climacium dendroides + + II 3 Lysimachia vulgaris + + II 3 Accompanying species Thuidium delicatulum V 2460 Alnus glutinosa a IV 750 Betula pendula a V 627 Oxalis acetosella V 545 Rubus saxatilis V 417 Viburnum opulus c IV 297 Amblystegium serpens 1 1 II 167 Frangula alnus b + 2 II 293 Frangula alnus c + + II 3 Sonchus oleraceus V 253 Viola mirabilis V 8 Maianthemum bifolium V 92 Dryopteris carthusiana IV 7 Mnium rostratum III 168 Ribes nigrum IV 7 Galium aparine III 5 Plagiothecium succulentum 1 1 II 167 Carex pallescens IV 7 Leucobryum glaucum + + II 3 Polytrichum attenuatum IV 7 Populus tremula a IV 7 [33]

35 Serial number of releve Fidelity Releve surface m class Coefficient of sp.cover degree a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Sphagnum fallax V 8 Sphagnum palustre IV 7 Sporadic species in releve No: 1- Polygonum multiflorum +; 5- Vaccinium vitis-idea +, Galium schultesii +, Corylus avellana b +, Ranunculus repens +, Cardamine amara +, Equisetum sylvaticum +, Luzula multiflora +, Peucedanum palustre +; 3- Pinus sylvestris a +; 4- Acer platanoides c +, Chrysosplenium alternifolium +; 5- Actea spicata +, Scirpus sylvaticus +, Rubus idaeus 1, Athyrium filix-femina +, Lycopus europaeus +, Geranium robertianum +, Geum rivale +; 6-Convallaria majalis +, Juniperus communis +, Dicranum scoparium +. Table 18. Trzyrzeczki - Drying riparian forest in transition to oak-hornbeam forest Serial number of releve Fidelity Surface of releve m class a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Ch. Cl. Vaccinio-Picetea Coefficient of sp.cover degree Pinus sylvestris a + + II 3 Picea abies a Picea abies b Picea abies c V 1045 Sorbus aucuparia b + + Sorbus aucuparia c IV 7 Ch. Cl. Querco-Fagetea Impatiens noli-tangere II 1627 Mnium undulatum III 752 Ulmus glabra a Ulmus glabra b Ulmus glabra c V 295 Tilia cordata b Tilia cordata c 1 1 III 168 Lonicera xylosteum c 1 + II 85 Padus avium b + 1 II 85 Padus avium c III 5 Acer platanoides c III 5 Paris quadrifolia V 8 Viola reichenbachiana III 5 Stellaria nemorum + + II 3 Adoxa moschatellina + + II 3 Quercus robur c + + II 3 Ch. Cl. Molinio-Arrhenatheretea Climacium dendroides 1 1 II 167 Lysimachia vulgaris IV 7 Filipendula ulmaria + + II 3 Cirsium palustre + + II 3 This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [34]

36 Serial number of releve Fidelity Surface of releve m class a-tree layer, b-shrub layer, c-herbaceous layer, d-moss layer Ch. Cl. Artemisietea Coefficient of sp.cover degree Urtica dioica II 628 Geranium robertianum III 378 Galium aparine V 8 Eupatorium cannabinum + + II 3 Accompanying species Betula pendula a III 1043 Rubus idaeus II 960 Oxalis acetosella II 878 Ribes nigrum IV 462 Geum rivale V 382 Dryopteris carthusiana II 377 Amblystegium serpens IV 252 Sonchus oleraceus V 172 Thelypteris palustris IV 7 Frangula alnus b + + Frangula alnus c + + II 3 Carex riparia 1 + II 85 Viburnum opulus c + + II 3 Populus tremula a III 5 Athyrium filix-femina III 5 Padus serotina + + II 3 Humulus lupulus + + II 3 Sporadic species in releve No: 1-Chrysosplenium alternifolium 1,Padus avium c +, Dryopteris filix-mas +, Hydrocotyle vulgaris +; 2-Carpinus betulus b i c +, Alnus glutinosa c, Carex panicea +, Populus tremula b i c +, Phragmites australia +; 3-Trientalis europea +, Plagiothecium succulentum +; 4- Scutellaria galericulata +, Lysimachia thyrsiflora +, Epilobium palustre +, Crataegeus monogyna +; 5- Sorbus aucuparia a 1, Lycopus europeus +; 6-Betula pendula b +, Actea spicata +. The nutrient demand of respective dominating species in the investigated habitats was determined (Table 19, Fig. 6) and the spectra of plant nutrient demand were established for each of the above communities (Fig 17,18). Table 19. Mean values of total sum of element (mmol c /kg) in plant species. Plant species Sum of macroelements Sum of microelement Total sum of elements in mmol c /kg in mmol c /kg in mmol c /kg Calluna vulgaris Vaccinium vitis-idaea Vaccinium uliginosum Ledum palustre Festuca ovina Deschampsia flexuosa Vaccinium myrtillus Carex paradoxa (appropinquata) Eriophorum vaginatum [35]

37 Plant species Sum of macroelements Sum of microelement Total sum of elements in mmol c /kg in mmol c /kg in mmol c /kg Lazula pilosa Molinia caerulea Carex acutiformis Phalaris arundinacea Pteridium aquilinum Carex riparia Carex nigra Thelypteris palustris Trientalis europaea Scirpus silvaticus Phragmites australis Calamagrostis arundinacea Melampyrum pratense Comarum palustre Salix aurita Convallaria majalis Hepatica nobilis Oxalis acetosella Dryopteris carthusiana Geum rivale Athyrium filix-femina Filipendula ulmaria Maianthemum bifolium Stellaria holostea Equisetum fluviatile Ranunculus acris Rubus idaeus Lathyrus vernus Ribes nigrum Pulmonaria obscura Rubus caesius Menyanthes trifoliata Asarum europaeum Caltha palustris Geranium robertianum Angelica sylvestris Galeobdolon luteum Aegopodium podagraria Rumex obtusifolius Impatiens noli-tangere Cicuta virosa Urtica dioica Humulus lupulus Sambucus nigra Species are divided according to sum of elements: 1. less than 1500 mmolc/kg mmolc/kg 3. more than 3001 mmolc/kg These groups are marked with different shades. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [36]

38 Figure 17. Spectrum of plant nutrient demand. a) b) c) d) [37]

39 Figure 18. Spectrum of plant nutrient demand for nitrogen. a) b) This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [38]

40 [39] c) d)

41 It was shown that in the drying alder and alder ash woods there dominate plants with a high and very high nutrient demand. These findings match the results of soil study concerning the acceleration of peat decay and the release of nitrogen to the soil and ground water, thus the species of the Class Artemisietea and other eutrophic species such as Impatiens noli-tangere and Aegopodium podagraria of the Class Querco-Fagetea may constitute good indicators of changes in wet woodland habitats due to, among others, climate change pressure. Habitat conditions at the Barwik transect located in the Southern Basin of the Biebrza valley significantly differ from the situation at the Szuszalewo transect located in the Northern Basin of the Biebrza valley. This transect encompasses the portion of the Biebrza valley not subject to annual flooding and situated closer to the edge of the river valley. The Szuszalewo transect was delineated on the peat bogs paludified with groundwaters, where the mosaics of low sedge-moss meadows were developed as a result of traditional land use (moving with biomass removal). The sedge-moss meadows embrace communities from the Class Scheuchzerio-Caricetea nigrae, and specifically from the Alliance Caricion nigrae, with such sedges as: Carex nigra, C. rostrata, C. canescens, C. diandra, C. appropinquata, C. fusca, C. paradoxa and in the moss layer - Calliergonella cuspidata, Aulacomnium plaustre, Drepanocladus aduncus and Mnium rostratum. Patches of the above community are intertwined with patches of the brown moss sedge phytocoenoses of the Alliance of Caricion lasiocarpae, build by such species as: Carex limosa, C. chordorrhiza, C. lasiocarpa, Menyanthes trifoliata, Comarum palustre, Eriophorum angustifolium as well as mosses: Drepanocladus aduncus and Scorpidium scorpioides (Table 20). These meadows have been artificially maintained due to annual late summer moving, recently, however, they become increasingly overgrown with downy birch Betula pubescens and black alder Alnus glutinosa. As it can be seen from the analysis of spectra of plant nutrient demand, the dominating species (sedges) have either low or medium nutrient requirements (Table 19, Fig.17d, 18d). Table 20. Szuszalewo - sedge meadows from Cl. Scheuchzerio-Caricetea nigrae Serial number of releve Releve surface m Fidelity class Ch. Ass. Caricetum lasiocarpae Carex lasiocarpa V Ch. Cl. Molinio-Arrhenatheretea Cardamine pratensis IV Epilobium palustre II Caltha palustris II Cirsium palustre III Carex caespitosa II Valeriana officinalis II Molinia caerulea + + I Ch. Cl. Scheuchzerio-Caricetea nigrae Comarum palustre III Menyathes trifoliata IV Carex panicea III Carex lepidocarpa II Pedicularis palustris + + I This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [40]

42 Eriophorum angustifolium II Carex limosa + + I Parnassia palustris + + I Drepanocladus aduncus II Drepanocladus vernicosus 3 I Accompanying species Betula pubescens b + + I Betula pubescens c III Pinus sylvestris c + + I Salix repens II Salix cinerea II Carex elata II Equisetum fluviatile III Galium palustre III Carex paradoxa III Peucedanum palustre II Aulacomnium palustre IV Calliergonella cuspidata III Mnium rostratum III Calliergon cordifolium II Dactylorhiza incarnata II Sporadic species in releve No: 1-Liparis loeselii +, Lycopus europaeus +; 2-Salix aurita +; 5-Filipendula ulmaria +, Ranunculus repens +; 5-Betula pendula b +; 6-Cirsium oleraceum +;8-Carex nigra +, Viola palustris +; 9-Salix rosmarinifolia +, Eupatorium cannabinum +, Linum catharticum +, Senecio paludosus +; 10-Cirsium rivulare +, Ranunculus acris +, Juncus articulatus +, Frangula alnus +. The Grzędy transect, situated on mainly mineral soils, in the Central Basin of Biebrza valley encompasses forests on dune elevations and swampy alder and birch woods in the depressions with sedge beds communities in situations closer to the river bed. The dune elevations are occupied by communities of the mixed coniferous forest Calamagrostio arundinaceae Piceeetum in its transitional stage to Querco-Piceetum with spruce stands Picea abies, and oak Quercus robur, downy birch Betula pubescens, aspen Populus tremula and alder Alnus glutinosa as an admixture. The understory layer is heterogenic and consists of: Vaccinium myrtillus, Calamagrostis arundinacea, Dryopteris carthusiana, Luzula pilosa, Oxalis acetosella, Convallaria majalis, Maianthemum bifolium. In the depression, there is a stretch of a swampy coniferous forest Vaccinio uliginosi-pinetum with a stand of Pinus sylvestris, and the undestory build be Vaccinium uliginosum, Ledum palustre, Andromeda polifolia, Vaccinium myrtillus, Vaccinium oxycoccus, Eriophorum vaginatum, Molinia caerulea, Sphagnum fallax, Sphagnum magellanicum, Sphagnum cuspidatum, Pleurozium schreberi, Polytrichum commune. This community displays signs of drying out what is seen in the decreased abundance and vitality of such species as Ledum palustre and Andromeda polifolia, and a simultaneous increase in the share of Molinia caerulea and Vaccinium myrtillus (Table 21). [41]

43 Table 21. Grzędy - Swampy pine forest Vaccinio uliginosi-pinetum Serial number of releve Fidelity class Releve surface (m 2 ) Ch. Cl. Vaccinio-Picetea Pinus sylvestris a Pinus sylvestris c IV Betula pubescens a Betula pubescens b Betula pubescens c V Vaccinium myrtillus V Vaccinium uliginosum V Pleurozium schreberi V Ledum palustre V Hylocomium splendens V Frangula alnus b + + Frangula alnus c II Vaccinium vitis-idaea + 1 I Molinia caerulea I Viscum album + + I Ch. Cl. Querco-Fagetea Quercus robur a 1 + Quercus robur b Quercus robur c V Ch. Cl. Oxycocco-Sphagnetea Eriophorum vaginatum V Oxycoccus palustris IV Sphagnum capillifolium III Aulacomnium palustre III Andromeda polifolia III Ch. Cl. Scheuchzerio-Caricetea nigrae Sphagnum fallax V Sphagnum palustre V Sphagnum magellanicum IV Sphagnum cuspidatum 3 1 IV Accompanying species Picea abies a Picea abies b Picea abies c V Dicranum polysetum IV Polytrichum formosum III Brachythecium rutabulum III Lophocolea heterophylla III Calluna vulgaris + + I Dryopteris carthusiana + + I Plagiomnium cuspidatum + + I This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [42]

44 Serial number of releve Fidelity class Releve surface (m 2 ) Rubus idaeus + + I Sporadic species in releve No: 4- Rubus saxatilis -+; 8 -Drypteris filix-mas - +; 9- Polytrichum juniperinum -+; 10- P. strictum -+, Carex sp.+; 11- Dicranella heteromalla +. Along the edges of local dune elevations there are stretches of oligotrophic peat moss alder swamp woods with black alder stands mixed with downy birch Betula pubescens and willows: Salix cinerea and Salix pentandra, while in the underbrush there are mainly reed species: Carex elongata, Thelypteris palustris, Lycopus europaeus and Phragmites australis. Among the moss layer there dominate peat mosses: Sphagnum palustre and S. squarrosum. Habitats of alder swamp forests in the central part of the transect are much more fertile and have a transitional character to the blackcurrant alder swamp woods with Ribes nigrum, Frangula alnus, and Calamagrostis lanceolata, Carex elongata, Carex remota, Carex pseudocyperus, Carex acutiformis, Iris pseudoacorus, Urtica dioica, Poa trivialis, Geranium robertianum, Thelypteris palustris, Lycopus europaeus, Solanum dulcamara, Galium aparine, Peucedanum palustre, Rubus ideaeus in the herbaceous layer. The spectra of nutrient demand for the dominating plant species sampled in the Grzędy transect show that most of the plants have either low or medium demand for nutrients (Table 19 Fig. 17b, 18b). 8. Plant chemical composition bioindicator of habitat changes Analysis of more than 50 plant species sampled on 18 study plots in four transects in BNP has shown that they can be divided into five groups according to their level of nutrient demand, into groups having low, medium, high, and very high nutrient demand. Between species differences within a group were always lower than those between groups. For the evaluation of species nutrient demand a special method developed by the author was applied (Ostrowska, 1987). The main assumption of this method is that the sum of all elements in the plant mass unit determines the total nutrient demand of a species, while the percent proportion of individual element in this sum defines the demand for that particular element. Both the excess and deficit of respective elements in the growth environment may disturb the between element proportions in the element sum. Plant species of low nutrient demand use around 2,300 mmol c for the production of 1 kg of mass, while those having very high demand around 6,000 mmol c, and even more. In the investigated plant species the element sum per mass unit fluctuated from about 1,400 to some 6,800 mmol c /kg (Table 19). The differences in nutrient demand between plant groups were highly significant (Table 19, 22). [43]

45 Angelica sylvestris Athyrium filix-femina Calamagrostis arundinacea Carex nigra Carex paradoxa (appropinquata) Carex riparia Convallaria majalis Dryopteris carthusiana Eriophorum vaginatum Filipendula ulmaria Galeobdolon luteum Impatiens noli-tangere Ledum palustre Molinia caerulea Oxalis acetosella Phragmites australis Ribes nigrum Rubus idaeus Stellaria holostea Thelypteris palustris Urtica dioica Vaccinium myrtillus Vaccinium uliginosum Vaccinium vitis-idaea Table 22. Significance of differences between the sum of elements accumulated in plants (mmol c /kg) Plant species Angelica sylvestris Athyrium filix-femina Calamagrostis arundinacea Carex nigra Carex paradoxa (appropinquata) Carex riparia Convallaria majalis Dryopteris carthusiana Eriophorum vaginatum Filipendula ulmaria Galeobdolon luteum Impatiens noli-tangere Ledum palustre Molinia caerulea Oxalis acetosella Phragmites australis Ribes nigrum Rubus idaeus Stellaria holostea Thelypteris palustris Urtica dioica Vaccinium myrtillus Vaccinium uliginosum Vaccinium vitis-idaea high; + medium; - no differences. This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [44]

46 The ion sum composition varied between plants with respect mainly to the element availability, plant development phase (senescence), but also depends on the plant part analyzed. The average value of ion sum in leaves of plants at the top of their assimilation capacities and an adequate nutrient supply amounts to % N, 2-3 % P, % K, 3-4 % Ca, 6-8 % Mg and few percent of the remaining elements. As plant senescence advances there is a drop in nitrogen share and an increase in the share of calcium. The nitrogen share is also lower and that of calcium higher in the lignified parts of plants stems and roots (Ostrowska, Porębska 2002). In our study, we sampled the whole above-ground parts of plants, therefore larger differences were found in the element sum composition, depending on the mass proportion of stems and leaves in a sample. The correlations between the contents of elements in plants, in particular those between nitrogen and other elements are significant (Table 23). Table 23. Pearson correlation coefficients between elements in plants. Ions (mg/kg) N P K Ca Mg Na S Mn Al Fe Zn Cu Pb Cd N P K Ca Mg Na S Mn Al Fe Zn Cu Pb Cd It should be emphasized that plants sampled at the study plots in the BNP showed a lower proportion of potassium and phosphorus than the same species growing elsewhere (Ostrowska, Porębska 2002). Particular attention was paid to the accumulation of nitrogen by plants in the BNP in view of its mass migration to the soil solution as a result of SOM mineralization. It should be noted that nitrogen next to carbon has a highest share in the sum of elements which build the plant biomass. The share of nitrogen in the element sum, in the plants investigated, fluctuated from 30 to about 60% and more. Plants with lower nutrient demand were found to have a higher nitrogen share in the element sum. Inverse pattern was observed as to the calcium share in the element sum, since the enhanced share of nitrogen diminished that of calcium. The interactions between nitrogen and calcium within the element sum were discussed also in an earlier work (Ostrowska, Sienkiewicz, 2011). As to the remaining elements there were no clearcut relations between their shares in the sums of elements accumulated per a mass unit of the respective plant species. [45]

47 9. Evaluation of relationships between soil quality and element accumulation in plants Chemical composition of plants is widely thought to reflect the soil quality. However, this relationship has never positively been determined, due at least to the fact that plant growth and development depends on many factors. It was earlier documented that the accumulation of elements in the plant biomass produced within a given space is a function and measure of soil capacities to maintain element migration to plants (Ostrowska, 2002). Soil solutions constitute a direct source of plant nutrients. There was a significant correlation between the contents of elements in plants and soil solutions in the case of the following relationships: N/Ca; N/Mg; N/K and N/S (Table 24). This evidences the relationship between the stock of available nutrients in soils and their uptake by plants (Table 24). Table 24. Comparison of significance of differences between the sum of elements accumulated in plants (a) and soil solutions (b). a) Ions (mg/kg) N P K Ca Mg Na S Mn Al Fe Zn Cu Pb Cd b) N P K Ca Mg Na S Mn Al Fe Zn Cu Pb Cd Ions (mmol c /kg) Cl SO 4 N-NO 3 N-NH 4 Ca-ss Mg-ss Na-ss K-ss Fe Al-ss Mn Cu Zn Sum Cl SO N-NO N-NH Ca-ss Mg-ss Na-ss K-ss Fe Al-ss Mn Cu Zn Sum This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [46]

48 Though the scarcity of data does not allow for a straightforward documentation of these relationships, we established the nutrient demand of plants most representative of every plant community in the series along the respective transects in the BNP. Along the transect at Barwik, six plant communities/habitats were identified from a tall sedge bed and various alder woods on peat soils to mixed spruce-oak forest in the mineral part of the Biebrza valley. In these communities, the dominating (typical) species were selected with markedly varying nutrient demands Figs. 6a, 17a). It was found that the most homogenous with respect to species nutrient demand are sedge beds, where species of a low and medium nutrient demand prevail, while the most diversified are swampy forest habitats with dominating plants of high nutrient demand. The nutrient pool in the organic soil examined is at least by about an order of magnitude higher than that in various forest mineral soils (Porębska 2002). Therefore it can be assumed that nutrient pool is high enough in all of the investigated habitats to ensure sufficient supply of elements for various plants having different demands for nutrients (Fig. 17a). Taking into account that peat decay results in the increased migration of nitrogen to the soil water, a comparison was made between the contents of nitrogen in soils and the share of nitrogen in plant species representing the respective habitats along the transect. It can be suggested that the following relationship: the more nitrogen in the soil the higher its content in plants, is more pronounced than the relationship between the element contents in soil solutions and these contents in plants. At high nitrogen availability in the growth environment, the nitrogen share in the element sum is higher in plants having low and medium nutrient demand than in those of high nutrient demand (Fig. 18). Along the Trzyrzeczki transect, the plants were sampled from five habitats (Fig. 6c) and the distribution pattern of dominant species with respect to their nutrient demand was similar as in the Barwik transect. Species of mainly medium or low nutrient demand dominate in the sedge meadow habitats (Carex spp.), while in the forest ecosystems there prevail species having a high nutrient demand including: Impatiens noli-tangere, Urtica dioica, Geranium robertianum and Aegopodium podgraria (Fig. 17c). The soils at Trzyrzeczki are more homogenous than at Barwik and richer in dissolved elements (Fig. 17c). In the four habitats identified at the Grzędy transect (Fig. 6b), there dominate plants with low and medium nutrient demand (Fig. 17b) This transect was delineated on mostly mineral soils which are poorer than the soils at the remaining transects. The most homogenous with respect to habitat differentiation is the Szuszalewo transect where dominating plants are various sedge species. Though these vary with respect to their nutrient demand, in general it was found that the dominating species at Szuszalewo have low or medium requirements, even that the local soils are richer in plant available nutrients than the soils at Barwik and Trzyrzeczki transects. [47]

49 10. Evaluation of relationships between the soil- and plant nutrient contents A significant correlation (r = -0.62) was found between the soil carbon and the sum of elements accumulated in plant biomass as well as between the soil carbon and the share of nitrogen (r = 0,52) in the sum of elements accumulated in plant biomass. The correlations between the remaining soil and plant attributes were not significant, what may be due to a low number of data available. The organic soils at the Barwik transect vary in the content of carbon from % to %, what may testify to the advancement of peat decay processes (Fig. 2a). From a comparison of spectra of the plant nutrient demand in respective communities along the transects examined (Fig. 17a) it becomes clear that species with lowest nutrient demand occur on soils having the highest carbon content (Fig. 2a) as is to be observed at Szuszalewo and, to some extent also at Grzędy. On the other hand, at a low content of carbon - < 20 %, as at the Trzyrzeczki and Barwik transects (Fig. 2a,c) there occur species of high and even very high nutrient requirements (Fig. 17a,c). Soils at the Grzędy site are mostly shallow largely undisturbed peat soils underlain by mineral materials, mainly sands. Species in the swampy pine forest Vaccinio uliginosi-pinetum growing on those sites have low and medium nutrient demand (Figs. 1b, 2b, 17b). Peat soils at the Szuszalewo transect differ in carbon content (Fig.1d, 2d) while the local plant communities are largely homogenous and build by species of low or medium nutrient demand. No wonder therefore, that the correlation coefficients for the correlation between the soil carbon and the sum of elements accumulated in a plant mass unit in Szuszalewo, are negative. Whereas nutrient pools in all of the investigated soils (habitats) were estimated as satisfying to ensure nutrient demands for any plant, it is noteworthy to point out that species of high nutrient demand dominate in habitats with decaying peat soils (moorshy soils), as was found at the Barwik transect. In these soils, there occurs a significant migration of nitrogen to soil solution. Therefore the increased presence of nitrophilous plants of the Class Artemisietea in drying phytocoenoses of swamp forests constitutes an indicator of habitat degradation. In the Biebrza valley it was found that the species such as Impatiens noli-tangere, Aegopodium podagraria, Urtica dioica, Geranium robertianum, Galium aparine, Geum urbanum, Anthriscus silvestris and Galeopsis pubescens tend to appear with higher fidelity classes and high coefficients of species cover in the drying alder wood and the riparian alder-ash wood at the Barwik and Trzyrzeczki transects. 11. Prognosis of changes in soils and plant communities in the Biebrza National Park (Biebrza River valley) based on reconstruction of the past and forecast of the future local climate conditions. The reconstruction of climatic phenomena in the Biebrza valley in the succeeding decades between 1950 and 2000, helped to establish that there was a consistent rise in average temperatures, especially in cold seasons. For warm periods only a slight rising trend was observed. The amount of precipitation varied between the decades, while the last one ( ) was distinctly dryer than the whole preceding period (Table 25, Fig.19). This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [48]

50 Table 25. Precipitation and temperature in averaged over the Biebrza catchment (based on the EOBS dataset). Decades Precipitation [mm] XI-III Precipitation [mm] IV-X Temperature [ o C] XI-III Temperature [ o C] IV-X Figure 19. Temperature (right panel) and seasonal precipitation (left panel) averaged over the Biebrza catchment for the cold and warm seasons, respectively. Temperature during the cold season shows more variability than in the warm period, also an increasing trend for the cold season can be noticed. On the other hand, precipitation is much more variable in the warm season, it is difficult to find any clear tendency. The modelling approaches applied in our study (Liszewska 2011 expertise: Reconstruction of climate between the years and scenario for the Biebrza valley in consideration of study transects, until the year 2080) allowed for a more detailed reconstruction of the past course of climate conditions in the Biebrza valley with a clear resolution at least to two of the three Biebrza river basins wherein the respective transects under study are located, and namely to Southern Basin where there is the Barwik transect, and to Northern Basin where the Szuszalewo and Trzyrzeczki transects are situated. The remaining transect at Grzędy is located in Central Basin within the intermediary zone of local climatic conditions. The forecast for climate change in the Biebrza valley, according to the above climate change scenarios suggests that there will be further rise in winter temperatures and further changes in the distribution and dynamics of precipitation pattern. (Table 26 ). [49]

51 Table 26. Precipitation [mm] and temperature [ o C] averages for decades for selected transects in the Biebrza catchment (based on the EOBS dataset). Precipitation [mm] in XI-III (cold season) Decades Barwik (N 53.37, E 22.57) Grzedy (N E 22.82) Trzyrzeczki (N E 23.23) Szuszalewo (N E 23.36) Precipitation [mm] in IV-X (warm season) Decades Barwik (N 53.37, E 22.57) Grzedy (N E 22.82) Trzyrzeczki (N E 23.23) Szuszalewo (N E 23.36) Temperature [ o C] in XI-III (cold season) Decades Barwik (N 53.37, E 22.57) Grzedy (N E 22.82) Trzyrzeczki (N E 23.23) Szuszalewo (N E 23.36) Temperature [ o C] in IV-X Decades Barwik (N 53.37, E 22.57) Grzedy (N E 22.82) Trzyrzeczki (N E 23.23) Szuszalewo (N E 23.36) The two Biebrza Basins vary in the past climatic conditions with respect to precipitation volume and the course of temperatures in a way that the Barwik transect is to be included into the warmer and dryer climatic area while the Szuszalewo transect into the colder and wetter one. Average winter temperatures over the 50 years examined were higher at Barwik by about 0.5 o C than those at Szuszalewo. On the other hand, the average annual precipitation sums were higher at Szuszalewo than at Barwik for both warm and cold seasons. These differences fluctuated around mm in almost all decades what suggests that water supply to the Barwik was lower by about m 3 /ha annually over the five decades examined (Table 26, Fig 20, 21). This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [50]

52 Figure 20. Examples of seasonal temperature [ o C] and precipitation [mm] in reconstructed using the EOBS data set (Haylock et al., 2008). 1 Barwik transect 2 Grzędy transect 3 Trzyrzeczki transect 4 Szuszalewo transect [51]

53 Figure 21. Example of seasonal temperature [ o C] and precipitation [mm] in reconstructed using the EOBS data set (Haylock et al., 2008). 1 Barwik transect 2 Grzędy transect 3 Trzyrzeczki transect 4 Szuszalewo transect Climate differences between the two basins may be evidenced by the rate of soil degradation processes in the two habitats compared. Thus, climate induced effects in habitats shall be considered against the local background conditions. At Szuszalewo in the Northern Basin the peat soils supporting the homogenous sedge beds are mostly deep and undisturbed, while at Barwik the soils of swampy woods are largely differentiated with a marked processes of peat decay. It is to be expected that the forecasted increase in temperature and disturbances in the precipitation volume and distribution (climate warming) will contribute to the intensification of peat decay, in particular at the Barwik site, and lead to further changes in local phytocoenoses and shifts in species composition (Fig. 22, 23, 24). The obvious consequence of climate warming is accelerated SOM mineralization (soil moorshing peat decay) which proceeds in several phases. In the first stage there occurs quasi eutrophication of peat soils marked by a rapid release of nitrogen to the groundwater, what favours the expansion of plants having a high nutrient demand. In further stages of soil decomposition, the pool of nutrients This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [52]

54 available to plants decreases what leads to profound changes in the structure and species composition of local communities. In order to stop or check the processes of soil degradation in wetlands of the Biebrza valley it is necessary to undertake all activities focusing on water retention, what means that no drainage can be allowed within the BNP and in its immediate surroundings. Figure 22. Seasonal mean temperature [ o C] and seasonal sum of precipitation [mm] averaged over the Biebrza catchment, projected in 7 selected simulations of the ENSEMBLES EU Project. Red line mean of the ensemble, grey areas determined by minimum and maximum of the ensemble of realizations, upper panel warm season, lower panel cold season. Blue line mean of the ensemble, grey area is determined by minimum and maximum of the ensemble, upper panel warm season, lower panel cold season. An increasing trend in the case of temperature, especially for the cold season is well marked. Precipitation, particularly during warm months, shows a wide area of uncertainties. Precipitation in cold months slightly increases during the last century. [53]

55 Figure 23. Spatial distribution of seasonal temperature [ o C]and precipitation [mm] in the NE Poland for subsequent decades in 21 st century ( ). 1 Barwik transect 2 Grzędy transect 3 Trzyrzeczki transect 4 Szuszalewo transect This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF [54]

56 Figure 24. Spatial distribution of seasonal temperature [ o C]and precipitation [mm] in the NE Poland for subsequent decades in 21 st century ( ). 1 Barwik transect 2 Grzędy transect 3 Trzyrzeczki transect 4 Szuszalewo transect 12. Literature 1. Braun Blanquet J., Pflanzensociologie III.Aufl.Wien.,pp Dzwonko Z., Assessment of light and soil conditions in ancient and recent woodlands by Ellenberg indicator values. Journal of Applied Ecology, 38: EEA: European Environment Agency 4. Expertises: External expertise: Małgorzata Bidłasik Preparation of the analyses results of soil richness in total nitrogen and soil mineral nitrogen of the selected investigation areas (Barwik, Trzyrzeczki, Grzędy and Szuszalewo) in the Biebrza National Park. Phytosociological background preparation of the ecotones maps of the Barwik, Trzyrzeczki, Grzędy and Szuszalewo investigation areas. (Outputs 4.2.6). Expertise under [55]