What ecosystem services can forests provide?

Transcription

1 Conference Adapting Forest Management to Maintain the Environmental Services Sept 2009, Koli, Finland What ecosystem services can forests provide? Bart Muys Forest Ecology and Management Research Group K.U.Leuven, Belgium

2 Ecoystem services, a new hype? Definition: benefits people obtain from ecosystems Popularized and formalized by MEA (2005) ECOSYSTEM SERVICES Supporting services Provisioning services Regulating services Cultural services Examples of forest ecosystem services (FES) nutrient cycling, gene pool, pollination Wood, non-wood forest products, drinking water Climate regulation, erosion control, windbreak Recreation, archaeology, religion

3 FES equal forest functions? FES Provisioning services (P) Regulating services (R) Supporting services (S) Cultural services (C) Forest functions Production function Protection function Ecological or Life supporting function Social or amenity function Land reserve

4 Managing ecoystem services Sustainable ecosystem management = (min S) + max [P,R,S,C] conservation Multiple use Challenge: participatory prioritization of P,R,S,C impacts of max (P,R,S,C) on S relationships between P,R,S,C Positive versus inverse Correlational versus causal Linear versus non-linear

5 Causal relations between FES Effect of Wood harvest BOC SOC Water recharge Erosion control Plant biodiversity Wood harvest BOC SOC Water recharge Erosion control Plant biodiversity Fill from experiments, observations, and expert knowledge

6 Causal relations between FES Effect of Wood harvest BOC SOC Water recharge Erosion control Plant biodiversity Wood harvest BOC SOC Water recharge Erosion control Plant biodiversity Feedback mechanisms: A improves B, but B degrades A (e.g. A= BOC; B= wood harvest) Feedforward mechanisms: A improves B, and B improves A (e.g. A=BOC; B=SOC in case of heathland afforestation) Strong non-linearity and probably strong site specificity

7 In search of FES theory Can we find order in this complexity? Could we find some general rules, e.g. Forests more performing than non-forests Natural forests more performing than plantations More diverse forests more performing than monocultures

8 Ecosystem exergy theory A model of self-organization in living systems with 4 key elements: 1. Ecosystems are open systems receiving exogenic exergy fluxes (mainly solar exergy); 2. Ecosystems absorb part of it to build up their internal exergy level (order from disorder) 3. Ecosystems maintain and improve this capability through inheritage and evolutionary learning (order from order) 4. Ecosystems with high exergy level can perform more work of dissipating exogenic exergy flows; they are better buffered, thus have higher stability Dewulf et al. (2008) Env Sci & Techn

9 Ecosystem exergy and FES Ecosystem Goal function Exergy storage Buffering activity Main exergy source Memory and learning max[buffer exergy flows] by max[exergy storage] biomass, structure, (DNA) Radiation gradients, temperature change, nutrient loss, water run-off, sediment loss, wind solar radiation Mainly DNA Supporting services Provisioning services Regulating services Wagendorp et al. (2006) Energy

10 exergy storage and ecosystem development Successional stage: Ecosystem attribute Abiotic (no vegetation) Developmental (pioneer vegetation) Mature (climax vegetation) Internal thermodynamic characteristics Entropy level High medium Low Exergy level (state and change) Low Medium High Gross production/ respiration Absent >1 Approaches 1 Gross production/ Absent High Low standing biomass Net production (yield) Absent High Low Biochemical diversity Absent Low High Stratification and spatial heterogeneity Absent Poorly organized Wellorganized Size of organisms Absent Small Large Growth form and life Absent r-strategy K-strategy cycle Niche specialization Absent Broad Narrow Information Low Medium High After Odum (1969) Science Provisioning services Biodiversity conservation

11 After Odum (1969) Science exergy dissipation and ecosystem development Successional stage: Abiotic Developmental Mature Ecosystem attribute External thermodynamic characteristics Dissipation rate of exogenic exergy flows Low Medium High Microclimate Weak Medium Strong (buffering of radiation, temperature and humidity changes) Control over water Low Medium High flows Control over nutrient Low Medium High flows Stability (resistance/ resilience to perturbations) Low Medium High Regulating services

12 Example: ecosystem thermal buffering Surface temperature from DAIS long wave scanner at St. Truiden, Belgium, 24 June 2001, am Dark blue is the temperature increase between and Maes et al. (2009) in prep. for Ecol. Mod.

13 Determination and chaos united Unidirectional succession rightfully criticized But exergy theory can be reconciled with chaos theory and alternative stable states (Kay, s.d., Dewulf et al., 2008) Species pool Disturbance regime Ecosystem service performance Performing newcomer added Dispersal limitation of pioneers Potential natural vegetation Forest ecosystem management Ecosystem Stability landscape Paraclimax (e.g. coppice, plantation, maquis) Thermodynamic equilibrium

14 Diversity/FES relationships Biodiversity function: Selection effect and insurance More species = higher probability of high performing species More species = higher probability of alternative pathways Complementarity Niche differentiation and facilitation

15 Diversity/FES relationships Diversity/productivity hypothesis provisioning services Diversity/stability hypothesis supporting and regulating services Net diversity effect (NDE) = [observed FES] [expected FES] Transgressive overyielding (Dmax) = [observed FES] [Max. single species FES] NDE<0: competition NDE=0: no effect NDE>0; Dmax<0: selection effect NDE>0; Dmax>0: complementarity effect

16 Diversity/FES in forests 1a. Species with similar ecological amplitude 1b. Species with different ecological amplitude 2a. Dashed: no interaction; continuous: overyielding; dotted: underyielding (from Pretzsch (2005) Ecol.Stud. 176) Transgressive overyielding in forests was demonstrated for the first time by Pretzsch & Schütze (2009) Eur. J. For. Res. In

17 Scale issues FES maximization on-site can have negative feedback off-site (e.g. green vs. blue water) Example: green water / blue water conflict Figure: % decrease in water discharge by an increase in vapor flow resulting from land use change to CDM-AR. Trabucco et al. (2008) Agr. Ecosyst. Env.

18 Integrated assessment of a. TWI 1 terrestrial/aquatic water services c. TAWI 1 ET min =0 ET PNV ET EWR AWI 1 0 TAWI ET min =0 ET PNV ET EWR b. d. ET min =0 ET PNV ET EWR 0 ET min =0 Water quantity impact as a function of land management a. in terrestrial ecosystems (TWI), b. in aquatic ecosystems (AWI), c. and d. on both aquatic and terrestrial ecosystems (TAWI) as a function of evapotranspiration (ET) of the potential natural vegetation (PNV) and a threshold ET EWR ET PNV,min ET PNV ET PNV,max ET EWR Maes et al. (2009) Env. Sci. Techn.

19 Integrated assessment of terrestrial/aquatic water services

20 Management issues sdss Afforestation system analysis Time Afforestation Strategy Initial system Metafore Afforested system Afforested system Gilliams et al. / New Forests (2005) 30:33 53

21 Example of a complex question solved in AFFOREST sdss by goal programming optimization What management strategy must be followed by a Danish municipality on sandy soils to produce a max. of clean drinking water and as a second priority max. C sequestration over the coming 15 years? How question looking for the afforestation strategy meeting the multiple objective with high weight on maximizing water recharge and minimizing nitrate leaching, and with low weight on carbon sequestration. FES optimization by simulation and DSS Best strategy = 14: afforestation of beech with moderate management intensity

22 FES optimization by simulation and DSS Where in NL plan 30,000 ha of oak forests for maximizing carbon sequestration, but not provoking nitrate leaching exceeding the drinking water norm of 50 mg/l? where question solved by the locate afforestation area query with multicriteria option. In order to get a focused answer it is wise to specify a time horizon and the used afforestation strategy. Heil et al. (2007) Springer Plant & Vegetation Series, 1

23 Some conclusions Optimizing between FES is a complex non-linear exercise Theoretically: Regulating services seem strongly related to late successional phases, while provisioning services more with early phases FES are high in PNV, but performance is influenced by species pool and disturbance regime FES might be higher and more sustained in diverse systems In practice: Effect of mixed forests on FES is not straightforward but has been demonstrated in a few cases Optimizing FES needs consideration of on-site and off-site effects at different scale levels Optimizing forest management for particular FES can benefit from mechanistic modeling and advanced optimization algorithms.

24 Conference September 2009 Koli, Finland Thank you for your attention Forest Ecology and Management Research Group K.U.Leuven, Belgium