grassland Timescales to achieve favourable condition

Transcription

1 Rehabilitation of existing priority lowland grassland Timescales to achieve favourable condition

2 Introduction This advisory note identifies the length of time that different management practices take to achieve favourable condition on existing priority lowland grassland habitats. The timescales and interim indicators can be used to assess the trajectory of site condition and whether habitat condition is progressing in a positive or negative direction. Lowland grassland priority habitat encompasses a range of species-rich semi-natural grassland communities. They have declined over the second half of the 20 th century, a variety of causes including agricultural improvement, urban development and abandonment where management cannot be continued or is no longer economically viable. Lowland grassland is still under threat and rare, covering around 3% of England s area, with an estimated 7,282 ha of lowland meadow, 870 ha of upland hay meadow, 38,687 ha of lowland calcareous grassland and 20,142 ha of lowland dry acid grassland (Bullock et al. 2011). The priority lowland grassland habitats featured in this advisory note include: Lowland meadows including dry and floodplain hay meadows and pastures. National Vegetation Classification (NVC) categories MG4-5 and MG8. Upland hay meadow dry and floodplain hay meadows and pastures that usually occur at less than 300 m in upland landscapes, and are generally managed in a similar manner to lowland meadows (mostly dry grassland). NVC categories MG3 and upland forms of MG8. Lowland dry acid grassland including species-rich bracken stands and inland dune grassland. NVC categories U2-U4, U4/20 and SD Lowland calcareous grassland - NVC categories CG1-10. Rehabilitation of existing priority lowland grassland 2

3 The botanical composition of floodplain meadows (MG4 and MG8), including positive and negative indicator species and the management related to rehabilitating and maintaining these grasslands, has been included in this advisory note. However, these grasslands are also a function of specific hydrological regimes, and timescales for rehabilitation relating to water management has not been included. Priority lowland grassland habitats not included in this advisory note are purple moor-grass and rush pasture (M22-26) and calaminarian grassland (OV37). Lowland grassland management is largely a balance between under- and over-management of these mid-successional habitats, with a closed sward that may be forb-rich in calcareous and neutral grassland or grassier in acid grassland. Scrub is an integral part of some of these grasslands, providing part of the habitat mosaic. Not every management practice is suitable for every site. For example, although many neutral hay meadows are managed with a cutting and aftermath grazing regime, this type of grassland can also be legitimately managed as pasture. Calcareous grasslands are usually managed as grazing pasture but there may be situations where grazing may not be suitable or practical, such as where the infrastructure is not present, and the grassland has to be cut instead. Also, each site will have a different starting point and it is not possible to cover every situation and reaction to management. No judgement is made within this advisory note on the most appropriate management practice and no advice is provided on management prescriptions. For information on the suitability and application of management practices, seek assistance from land management advisers and specialists, and consult available literature including: The Lowland Grassland Management Handbook (Crofts and Jefferson 1999; termed lowland grassland handbook throughout this document); The Wet Grassland Guide: managing floodplain and coastal wet grassland for wildlife (Benstead et al. 1997) A Practical Guide To The Restoration And Management Of Lowland Heathland (Symes and Day 2003; termed lowland heathland management guide where mentioned in this document); Magnificent Meadows website a directory of information regarding habitat management; The Floodplain Meadows Technical Handbook (Rothero, Lake and Gowing 2016); The Scrub Management Handbook (Bacon et al. 2003); Bracken Management and Control TINs 047 and 048 (Natural England 2008; 2009); The Use of Lime on Semi-Natural Grasslands TIN 045 (Natural England 2011); The Climate Change Adaptation Manual NE546 (Natural England and RSPB 2014). There is further background information on lowland grasslands and the Milestones to Recovery Project in the annex. Rehabilitation of existing priority lowland grassland 3

4 Lowland Grassland Condition Assessment Management of lowland grassland focuses on maintaining four attributes in favourable condition habitat extent, forb:grass ratio, positive indicator species and negative indicator species (Robertson and Jefferson 2000). The first attribute can only be measured at a site-specific level and is therefore not covered by this advisory note. The other three attributes are measured against generic thresholds across all lowland grassland sites, although the thresholds may be adjusted on a site-by-site basis to suit the local environment. In addition, there are three proxies that can be used to determine whether the grassland is declining in condition. These include height of vegetation, litter and bare ground. Failure of these secondary attributes does not trigger the condition to be considered as unfavourable, but they can be used to initiate a management response to address the reasons why the grassland condition is declining. Formal condition monitoring may be undertaken once every five or six years, but informal monitoring (site checks) may be undertaken at more regular intervals. Figure 1: Hypothetical model linking habitat condition with management and timescales on a neutral grassland. Cutting Cutting and aftermath grazing Relaxed grazing *T -Timescale with interim indicators Unfavourable declining Unfavourable recovering Unfavourable declining Favourable condition Unfavourable condition 1 Prior to management 2 Implementation of cutting 3 Implementation of cutting and grazing 5 Relaxation of grazing Management over time Condition attributes FG - Forb:Grass ratio Pos - Positive indicators Neg - Negative indicators FG Pos Neg FG Pos Neg FG Pos Neg FG Pos Neg FG Pos Neg Rehabilitation of existing priority lowland grassland 4

5 The outcome of condition monitoring is used to assess the status of the site, indicating whether it is in unfavourable or favourable condition. This results in the condition assessment of unfavourable recovering defined as all the necessary management measures are in place to address the reasons for unfavourable condition. Habitat and species features will recover to a favourable state, but in many cases this takes time (Natural England 2008). Grassland sites may remain in unfavourable recovering condition for a long period of time depending on the implementation and maintenance of management, reaction of the habitat and unforeseen events, such as a wet summer, which may delay or stop management. Figure 1 is a conceptual model of the relationship between grassland management and change in site condition. The condition of a site is a summary of the status of all the mandatory monitoring attributes, and each attribute needs to be achieved before the habitat is considered favourable. This is described in section 3 of figure 1, where cutting and aftermath grazing have been implemented on the neutral grassland. Different management interventions may be undertaken as time progresses, usually resulting in improved condition, such as cutting or grazing or cutting and grazing as suggested in figure 1. The management depends on the type of grassland, and further information on the most appropriate management used for different types of calcareous, neutral and acid grassland are included in the annex. Improvement in condition may be slow and can fluctuate, and it can be difficult to determine progression of recovery. As a consequence, it is not possible to readily judge where within unfavourable recovering condition the site falls and how long it may take to reach favourable condition. There is also the potential to hasten recovery by undertaking different management or a combination of management. In addition, some management practices or levels of implementation may result in a decline in condition depending on the site for example, the cessation of aftermath grazing suggested in figure 1. The length of time it takes for lowland grassland sites to reach favourable condition depends on the starting condition of the site and the management interventions employed. Each site is different and management that may result in a quick recovery to favourable condition on one grassland may take much longer or not be successful at a different site. In addition, there are cases where the initial trend following initiation of management is negative, before then having a positive effect. Thus, assessments based on early monitoring may be misleading and there is the potential that the management may be considered to be detrimental. To map the recovery of a site, timescales and interim indicators are required to understand how it is progressing. This advisory note provides generic guidance on these timescales, and this information could be used on a site-by-site basis to identify where within the broad unfavourable recovering category condition falls, and how long it may take for the site to recover depending on the management intervention undertaken. Rehabilitation of existing priority lowland grassland 5

6 How to use the keys and tables The following keys and tables are hyperlinked within this advisory note. Text highlighted in green follows the management pathway through the key to the tables that hold the timescale information. Text highlighted in blue or with has a pop-up box with details of where to find relevant management prescriptions in the literature. There is a key for each of the three condition attributes considered in this advisory note. To use this advisory note: Start with identifying the reasons why the site is failing to achieve favourable condition and the management interventions that will be or are being implemented to bring the site back into favourable condition. This will identify the keys that should be searched for timescale information. Work through the keys to arrive at the management intervention that has been identified as the most suitable to be implemented on the site. Follow the link to the relevant management intervention in the table, which has the interim indicators and timescale information. There may be several reasons why a site may fail favourable condition, and the appropriate key should be followed to reach the timescale information for each reason. This is the case where the site has failed condition on two different attributes, such as forb:grass ratio (in Key FG) and positive indicator species (in Key Pos); or where the site has failed for two different reasons within the same condition attribute, such as ragwort (Key Neg), which may be controlled by pulling, and creeping thistle (Key Neg), which may be controlled through a combination of herbicide application and extensive grazing. Rehabilitation of existing priority lowland grassland 6

7 Here are some examples of how to work through the keys to the relevant sections of the tables that contain the timescale information: A calcareous grassland has failed on forb cover as there has been a relaxation in grazing in recent years with a lower stocking level. Coarse grasses such as Yorkshire fog Holcus lanatus, cock s-foot Dactylis glomerata and upright brome Bromopsis erectus have grown creating clumps and there is an increase in litter. As a consequence, the lower growing forbs are outcompeted and over-shaded by the grasses, which has reduced flowering and seed set. Following consultation, the agreed management of increasing cattle grazing initially to higher than average stocking levels to reduce the vegetation height and coarse grass cover, followed by average stocking levels in the future as part of ongoing management, will be implemented (there is infrastructure present). Using Key FG, the first pathway (FG1) has the option changes to management practices which covers either relaxation or intensification of grazing that has occurred on the grassland. The pathway leads to a choice about management practices; livestock grazing is the second option. The hyperlink is connected to the table heading for livestock grazing, and in the box underneath there are timescales for calcareous grasslands. The timescale information suggests that on average, stocking levels recovery may take 1-3 years to restore calcareous grassland with cattle grazing if there are still forbs visible in the sward, or years if there are no forbs visible. A neutral grassland has failed on positive indicator species as it has been abandoned for a number of years, allowing the grass to form clumps and the forbs have declined. Following consultation, it is decided that the most appropriate management for the site is cutting with aftermath grazing. However, the infrastructure (fencing and water troughs) are dilapidated so only cutting can be undertaken at the moment. Using Key Pos, the first couplet (Pos 1) directs the pathway along negative management practices to Pos 2. Rehabilitation following abandonment is required so this option is followed to Pos 4, where the first option concerns cutting only. The management heading is hyperlinked to the table and the box under the table identifies that it may take years to rehabilitate neutral grassland by cutting alone. There is still debate about whether cutting alone can maintain the conservation value of neutral hay meadows that have been traditionally managed with mowing and aftermath grazing. Under the scenario suggested above, if positive indicator species do not increase in the neutral grassland under a cutting regime, the infrastructure may need to be repaired and aftermath grazing also initiated to fully rehabilitate the grassland. This is suggested by the last sentence at the bottom of the cutting neutral grassland management box and directs to the timescales under cutting and livestock grazing management. An acid grassland has failed on the negative indicators bracken and scrub. Using Key Neg twice, the management pathways for bracken and scrub management would need to be followed to identify the length of time it may take for the respective management to be effective. Due to the variable response of habitats to management interventions, none of the timescales in this document should be used to set targets or indicators of success within management plans. Instead, the timescales should be used as guides to the period of time whereby likely changes in habitat condition may be visible, resulting in better condition and movement through unfavourable recovering condition to favourable condition. Rehabilitation of existing priority lowland grassland 7

8 Degree of confidence for each milestone being achieved The timescales are based on evidence gathered through scientific studies, reported case-studies and consultation with experienced practitioners (Chant and Shellswell 2016; Shellswell 2016). This information has been combined to estimate the length of time following implementation of a management intervention or combination of interventions. Due to the variable nature of each site s starting point and differences in response to management, a period of time in years is usually provided. However, a site may not feature all of the interim indicators and recovery towards the desired ecological state may be faster or slower than stated. The timescales are based on the best available evidence at the time of writing this advisory note. A degree of confidence has been provided for each timescale: Low confidence that desired condition will be achieved within the timescale following the implementation of the management intervention Medium confidence that desired condition will be achieved within the timescale following the implementation of the management intervention Strong confidence that desired condition will be achieved within the timescale following the implementation of the management intervention Definition of terms Several common descriptive terms have been used in this document and are defined on the right, including for stocking densities and cover of grasses and negative species. This advisory note has been developed as an aid to help determine the possible timescales for the rehabilitation and maintenance of existing lowland grassland to favourable condition. Restoration and creation of lowland grassland habitat are not the focus of this advisory note, but are defined to provide a full understanding of the management practices that are covered and not covered. Maintenance to maintain the current extent and condition of existing priority habitat. This could be through a single or combination of management interventions, such as harrowing and livestock grazing. Rehabilitation to rehabilitate an existing priority habitat from unfavourable condition to favourable condition using conventional management interventions, such as hay cutting with aftermath livestock grazing. Restoration to improve a site s habitat quality from non-priority to priority habitat condition. This may be through controlling species such as bracken or scrub, or through seed addition where propagules are required to enhance the sward. Recreation (also known as expansion) to recreate a priority habitat from a non-priority habitat, such as arable reversion or from an agriculturally improved grass ley. This includes importing a seed source to act as propagules to enhance the sward which could be in the form of green hay, brush-harvested seed or handcollected seed, or using a commercial seed mixture. Propagules any structure capable of being propagated or acting as an agent of reproduction, or a plant part, such as a bud, that becomes detached from the rest of the plant and grows into a new plant. This includes seeds, stolons or rhizomes. Rehabilitation of existing priority lowland grassland 8

9 Stocking densities Grassland type Average High Lowland dry acid grassland c. 0.2 LU/ha/yr > 0.2 LU/ha/yr Lowland meadows (including pasture and upland hay meadows) c. 0.5 LU/ha/yr > 0.5 LU/ha/yr Lowland calcareous grassland c LU/ha/yr > 0.25 LU/ha/yr Coverage definitions High grass cover is over 60% cover and/or above the desired condition threshold for the particular grassland type Dense = frequent or more than 20% cover Patchy = more than occasional but less than frequent or less than 5% cover Lowland Grassland Management Timescale Keys There could be a single or several reasons for failure of the condition assessment. Identify the attribute(s) that are of concern to find the relevant key. Condition assessment attributes: Forb:grass ratio... Key FG Positive indicator species... Key Pos Negative indicator species... Key Neg Rehabilitation of existing priority lowland grassland 9

10 Key for Forb:Grass Ratio (Key FG) The generic ratio of positive broad-leaved herbs to grass should be between 40-90% for most priority lowland grasslands (Robertson and Jefferson 2000). Grasses are a fundamental component of the sward which is why the upper threshold is set at 90%, and also varies considerably between and within types of priority grasslands. Lowland dry acid grassland has a naturally high grass cover. Monitoring forb cover on this type of grassland could be misleading, hence it is not used as an attribute in the condition assessment. High grass cover is usually a sign of high soil nutrients which encourages the growth of competitive grasses out-competing many forbs. Negative indicators such as creeping thistle Cirsium arvense and widespread grassland species including white clover Trifolium repens, common sorrel Rumex acetosa, creeping buttercup Ranunculus repens, ribwort plantain Plantago lanceolata and yarrow Achillea millefolium also react positively to higher soil nutrients. An abundance of these forbs may potentially give a misleading high forb coverage, suggesting that the habitat is in favourable condition, but allude to undesirable soil nutrient levels and the potential for a decline in habitat condition. Creeping thistle is the only negative indicator formally used in this context under the monitoring guidance, but the other species mentioned may be used informally as potential negative indicators. Height of vegetation is a proxy measure that can be used to indicate that the habitat may decline, if not corrected. A higher sward may indicate under-management or could be a reaction to extraneous environmental variables, such as high spring rainfall which encourages grass growth, while a lower sward may indicate intensive management. The level of litter can also be used as a proxy measure for forb:grass ratio. Dense litter can be associated with greater grass coverage or a community that is succeeding towards a grassier composition due to relaxed or abandonment of management. Litter also has the effect of preventing forb seed from reaching the soil surface, and germinating and decaying litter adds nutrients to the soil thereby supporting more competitive species, all of which encourage grass growth over forb growth. FG 1 Management to address the impacts of: under-management and application of fertilisers (see FG 2) weather events (i.e. summer flooding) FG 2 Under-management of grasslands and grassland that have had fertiliser applied can be rehabilitated by: cutting livestock trampling and grazing cutting and livestock grazing low confidence medium confidence high confidence Rehabilitation of existing priority lowland grassland 10

11 Timescales for rehabilitation following weather events Cutting and livestock grazing Timescales for neutral grassland Following a summer flood of neutral grassland, resulting in a missed or late hay cut for one or more years, a double cut taken in July and late summer can reduce the coverage of bulky sedges to 20-35% and recovery of forb cover can occur within three years of instigating management. Timescales to rehabilitate grassland that has been under-managed or has had fertiliser applications Cutting Timescales for neutral grassland On lowland and upland neutral grassland managed by cutting alone, a single annual cut around early July (lowlands), mid-late July (uplands) maintains conditions suitable for forb species, particularly annuals, short-lived and longer-lived forbs, such as yellow rattle Rhinanthus minor, eyebrights Euphrasia sp., changing forget-me-not Myosotis discolour, lesser trefoil Trifolium dubium, great burnet Sangusorba officinalis and common knapweed Centaurea nigra. Occasional late cuts (one year in five) ensure late-flowering species, including meadowsweet Filipendula ulmaria and devil s-bit scabious Succisa pratensis, have the opportunity to set seed. Cutting should be followed by livestock grazing if there is suitable infrastructure or once infrastructure is repaired (see cutting and livestock grazing). Livestock trampling and grazing Timescales for calcareous grasslands Calcareous grassland can be rehabilitated using average stocking levels following abandonment within: 1-3 years with cattle grazing where forbs are still present in the sward and years on sites without forbs present in the sward (suggesting that there are no forbs present or at very low abundance); 1-2 years with sheep grazing where forbs are still present in the sward, and considerably longer on sites without forbs present (suggesting that there are no forbs present or at very low abundance); years with equine grazing on sites with or without forbs present in the sward; 1-2 years with mixed grazing where forbs are still present in the sward, 2-9 years with low forb abundance in the sward and 10+ years on sites without forbs present in the sward that are very under-managed (suggesting that there are no forbs present or at very low abundance). The period of time rehabilitation takes depends on stocking density, timings and breed and site characteristics including soil nutrients, seed sources (both within the site and in nearby areas of species-rich grassland) and time since abandonment. Calcareous grassland can become rank with excessive grass growth within 1-2 years if under-grazed. Some forbs increase in frequency very slowly for example, thyme Thymus sp. may take over 10 years. Rehabilitation of existing priority lowland grassland 11

12 Timescales for neutral grasslands Neutral grassland can be rehabilitated using average stocking levels following abandonment within: 1-3 years with cattle grazing where forbs are still present in the sward and years on sites without forbs present in the sward (suggesting that there are no forbs present or at very low abundance); 5-6 years with sheep grazing where forbs are still present in the sward, and considerably longer on sites without forbs present (suggesting that there are no forbs present or at very low abundance); years with equine grazing on sites with or without forbs present in the sward; 4-9 years with mixed grazing where forbs are still present in the sward and 10+ years on sites without forbs present in the sward that are very under-managed (suggesting that there are no forbs present or at very low abundance). The period of time rehabilitation takes depends on stocking density, timings and breed and site characteristics including hydrological conditions, soil nutrients, seed sources (both within the site and in nearby areas of species-rich grassland) and time since abandonment. Neutral grassland species that may increase in abundance following rehabilitation management include yellow rattle Rhinanthus minor, meadow buttercup Ranunculus acris, red clover Trifolium pratense, wood crane s-bill Geranium sylvaticum and common bent Agrostis capillaris. In neutral grassland, it can take over eight years for a change from a tall coarse grassland vegetation composition dominated by false oat-grass Arrhenatherum elatius, cock s-foot Dactylis glomerata and Yorkshire fog Holcus lanatus to one of finer grasses and greater forb coverage with extensive sheep grazing throughout the year. Cutting and livestock grazing Timescales for neutral grasslands Rehabilitation of forb cover in abandoned neutral grassland by hay cutting and aftermath grazing is likely to occur within 4-9 years of management commencing. Year-on-year variation of species and forb coverage can be significant. Positive indicator species can increase in abundance within 1-5 years. For example, oxeye daisy Leucanthemum vulgare may occur within two years and cowslip Primula veris, bird sfoot trefoil Lotus corniculatus and green-winged orchid Anacamptis morio may return within five years. Timescales for neutral grassland that have had fertiliser applications Neutral grassland that has received nitrogen inputs through fertiliser application can be rehabilitated to priority condition over time through cutting and livestock grazing management. It is estimated to take three, five, seven and nine years for rehabilitation following 25, 50, 100 and 200 N kg/ha/yr for a single year of application. Timescales for recovery increase with longer periods of application, and after four consecutive years it is expected to take five, 15, 23 and 30 years for rehabilitation of the forb:grass ratio at the same rates of application. Recovery of forbs will be affected by the extent of propagules remaining in the soil seed bank or as plant fragments. Neutral grassland may take over 15 years to recover from applications of phosphorus, which encourages greater grass growth to the detriment of forbs. Levels of phosphorus decrease at different rates depending on soil type. Recovery of forbs will be affected by the extent of propagules remaining in the soil seed bed. Rehabilitation of existing priority lowland grassland 12

13 Key for Positive Indicator Species (Key Pos) A sub-set of plants for each type of priority grassland is used to determine habitat condition. Generic targets for each type of grassland focus on the abundance (frequency and/or cover) of representative positive indicator species throughout the sward (Robertson and Jefferson 2000). Generically, there are at least two species frequent and two occasional for most types of grassland, but individual condition assessments should be referred to for each type of grassland (thresholds may differ within types of grassland). Positive indicator species are stress-tolerant plants characteristic of low soil nutrients and indicative of each priority type of grassland. Plants that are visible throughout the recommended survey season are chosen in preference to species present for a short period, or species that are more difficult to identify by non-botanical specialists, such as grasses, sedges and rushes. Positive indicator species are affected by both increases and decreases in management. For example, abandonment of management, such as a discontinuation of hay cutting and/or grazing, and intensification of management, such as cutting earlier in the year or more often throughout the year. Management for positive indicator species, as with all grassland management, relies on a balance between too much and too little management, and the balance of activity can vary annually depending on environmental factors. The period of time it takes to rehabilitate positive indicator species depends on the impact of the negative management or environmental event. All three secondary condition attributes litter, height of vegetation and extent of bare ground can be used as proxies to make a judgement that the condition is declining or being rehabilitated. Pos 1 Pos 2 Pos 3 Management to address the impacts of: negative management practices (see Pos 2) environmental factors and random (stochastic) events (see Pos 3) Negative management practices: intensification of management (i.e. more frequent mowing or high levels of stocking) abandonment of management (i.e. lack of mowing and/or grazing) (see Pos 4) application of fertilisers and lime (see Pos 5) Negative environmental impacts and random (stochastic) events: atmospheric nitrogen deposition (see Pos 5) weather events (i.e. summer flooding) climate change Pos 4 Rehabilitation following abandonment: cutting grazing cutting and livestock grazing Pos 5 Rehabilitation following a rise in soil nutrients caused by the application of fertiliser or atmospheric nitrogen deposition: cutting cutting and livestock grazing low confidence medium confidence high confidence Rehabilitation of existing priority lowland grassland 13

14 Timescales to rehabilitate intensively managed grasslands Cutting and livestock grazing Timescales for neutral grassland Rehabilitation of intensively managed neutral grasslands can be achieved over a period of years. Swards become more diverse under a hay cutting and aftermath grazing regime compared with just grazing, and if there is a source of propagules nearby or remnant positive indicator species present that can spread via seed or vegetatively. Neutral grassland, particularly floodplain meadows, can be rehabilitated from an intensive grazing regime by re-instating a hay making regime. Species that may become more abundant after five years include crested dog s-tail Cynosurus cristatus, meadow buttercup Ranunculus acris, red clover Trifolium pratense, and yellow rattle Rhinanthus minor. This is most suited to meadows that were traditionally managed for hay, as the vascular plants are adapted to this management regime and grasslands that still have some positive indicator species remaining in the sward. If these species do not become more abundant within five years, consideration should be given to introducing seed via sowing or green hay addition subject to policy and consent procedures. Timescales for rehabilitation following environmental events Cutting and livestock grazing Timescales for neutral grassland It may take 3-4 years for floodplain meadows to recover positive indicator species that have had a long period of standing water over the spring and summer, even when an annual hay cut and aftermath grazing can be undertaken. The water restricts plant growth, and coarser grasses are able to grow, out-competing and shading smaller forbs. Where standing water results in abandonment of mowing, recovery is slower and this is exacerbated if mowing cannot be undertaken in subsequent years. After severe flood events, it may take 7-10 years for positive indicator species to recover, particularly smaller forbs such as crested dog s-tail Cynosurus cristatus, red clover Trifolium pratense and field wood-rush Luzula campestris. If the summer flood cycle is shorter than the length of time rehabilitation management may take, there is the possibility that the vegetation community, including the positive indicator species, could be lost. Rehabilitation of existing priority lowland grassland 14

15 Timescales for rehabilitation following climate change Climate change winners and losers Timescales for calcareous grassland Using climate change modelling, there are predicted winners and losers under different warming scenarios and timescales. Predicted winners by 2050 include dwarf thistle Cirsium acaule, yellow-wort Blackstonia perfoliata and common rock-rose Helianthemum nummularium. Timescales for neutral grassland Using climate change modelling, there are predicted winners and losers under different warming scenarios and timescales. Predicted winners by 2050 include great burnet Sanguisorba officinalis in neutral wet meadows and losers include wood crane s-bill Geranium sylvaticum in upland meadows. Timescales for acid grassland Using climate change modelling, there are predicted winners and losers under different warming scenarios and timescales. Predicted winners by 2050 include Spanish catchfly Silene otites while common stork s-bill Erodium cicutarium may be a winner or loser depending on the availability of suitable habitat identified through the climate modelling. Timescales to rehabilitate soil nutrient levels Cutting Timescales on neutral grassland Rehabilitation of positive indicator species following a single application of fertiliser by taking one cut per year may take 3-4 years on some sites, but is more likely to take over five years. With two years of fertiliser applications, the timescale for rehabilitation is over five years with just a single cut per year, and following three or more successive years of fertiliser application, rehabilitation will take 10+ years with a single cut. Positive indicator species are likely to take over five years to re-establish after two successive years of fertiliser application by cutting the sward twice a year, and after three or more successive years of fertiliser application, it will take over 10+ years for positive indicator species to re-establish with two cuts per year. Some positive species indicators may take well over 10 years (if ever) to re-establish. For example, re-establishment of green-winged orchid Anacamptis morio has taken over 30 years following a single fertiliser application. Grasslands where lime has traditionally been applied, such as upland hay meadows, may benefit from maintaining a soil ph of 6 where it is applied with fertiliser (farmyard manure). Grasslands that have become more acidic over time through atmospheric deposition may benefit from lime applications, resulting in an increase in species richness within a short period of time. Where lime has not traditionally been applied, it can have damaging consequences, particularly on grasslands with acid soils and flora adapted to lower soil ph. Lime applications may affect the availability of nutrients for plants over a period of 15 years or more, making it easier for more competitive species to establish and reduce the available habitat for less competitive species, such as yellow rattle Rhinanthus minor. Rehabilitation of existing priority lowland grassland 15

16 Cutting and livestock grazing Timescales on neutral grassland Cutting the sward twice a year and aftermath grazing may enable positive indicator species to reappear within 3-4 years following a single application of fertiliser. However, some positive species indicators may take over 10 years to re-establish. On neutral grassland, it may take years for positive indicator species to re-establish after the cessation of fertiliser inputs by cutting and aftermath grazing management. Early successional species can include cowslip Primula veris, common knapweed Centaurea nigra, oxeye daisy Leucanthemum vulgare, yellow rattle Rhinanthus minor, ribwort plantain Plantago lanceolata, pepper-saxifrage Silaum silaus and fairy flax Linum catharticum. The grassland may still be poorer than a habitat that has never been fertilised, even after many years of rehabilitation management. Some neutral grassland positive indicator species may take well over 10 years (if ever) to re-establish. For example, re-establishment of green-winged orchids Anacamptis morio has taken over 30 years following a single fertiliser application. Timescales to rehabilitate abandoned grassland Cutting Timescales for neutral grassland It may take years for positive indicator species to re-establish to meet monitoring condition thresholds after the cessation of fertiliser inputs by mowing management. Early indicators that the habitat is progressing towards the desired condition on neutral grasslands can include cowslip Primula veris, common knapweed Centaurea nigra, pepper-saxifrage Silaum silaus and fairy flax Linum catharticum. The grassland will still be poorer than habitat that has never been fertilised, even after many years of rehabilitation management. Mowing can be used to rehabilitate grasslands, but is not as rapid as a combination of mowing with aftermath grazing. However, mowing may not be appropriate on all neutral grassland, such as that which has been traditionally managed as pasture (see livestock grazing). Grasslands abandoned more recently, have been under restoration management for a longer period of time and are close to a source of propagules may be rehabilitated more quickly than long abandoned hay meadows, grasslands that have been under restoration management for a short period of time or far away from a source of propagules. No exact timescales can be provided as the rate of rehabilitation depends on the interaction between these factors. Cutting may be followed by livestock grazing if there is suitable infrastructure or once infrastructure is repaired (see cutting and livestock grazing). Rehabilitation of existing priority lowland grassland 16

17 Livestock grazing Timescales for calcareous grasslands Calcareous grassland can be rehabilitated following abandonment within: years with cattle grazing; 10+ years with equine grazing; 4-9 years with mixed grazing. The period of time rehabilitation takes depends on stocking density, timings and breed and site characteristics including soil nutrients, seed sources (both within the site and in nearby areas of species-rich grassland) and time since abandonment. Calcareous grassland species that may increase in abundance soon after rehabilitation management include kidney vetch Anthyllis vulneraria, common milkwort Polygala vulgaris, devil s-bit scabious Succisa pratensis and autumn gentian Gentianella amarelle. Late successional species that are slow to establish include thyme Thymus sp., milkworts Polygala spp., dwarf thistle Cirsium acaule and glaucous sedge Carex flacca. Timescales for neutral grasslands Neutral grassland can be rehabilitated following abandonment within: five years with sheep grazing; years with cattle grazing; 10+ years with equine grazing; 4-7+ years with mixed grazing. The period of time rehabilitation takes depends on stocking density, timings and breed and site characteristics including hydrological conditions, soil nutrients, seed sources (both within the site and in nearby areas of species-rich grassland) and time since abandonment. Neutral grassland species that may increase in abundance soon after rehabilitation management include yellow rattle Rhinanthus minor, meadow buttercup Ranunculus acris, red clover Trifolium pratense, cow-parsley Anthriscus sylvestris, wood crane s-bill Geranium sylvaticum and creeping bent Agrostis capillaries. Timescales for acid grasslands Acid grassland can be rehabilitated following abandonment within: 7-9+ years with sheep grazing; 4-7+ years with cattle grazing; years with equine grazing; years with mixed grazing. The period of time rehabilitation takes depends on stocking density, timings and breed and site characteristics including hydrological conditions, soil nutrients, seed sources (both within the site and in nearby areas of species-rich grassland) and time since abandonment. Acid grassland species that may increase in abundance soon after rehabilitation management include sheep s sorrel Rumex acetosella, heath bedstraw Galium saxatile and pill sedge Carex pilulifera. A negative trend in acid grassland may become apparent in under-grazed swards with an increase in abundance of wavy hair-grass Deschampsia flexuosa and hawthorn Crataegus monogyna seedlings. Timescales for all types of grasslands Grasslands abandoned more recently, have been under restoration management for a longer period of time and are close to a source of propagules may be rehabilitated more quickly than long abandoned grasslands, those that have been under restoration management for a short period of time or far away from a source of propagules. No exact timescales can be provided as the rate of rehabilitation depends on the interaction between these factors. Rehabilitation of existing priority lowland grassland 17

18 Cutting and livestock grazing Timescales for neutral grasslands Mowing and aftermath grazing is the fastest method to rehabilitate abandoned grasslands. However, mowing may not always be appropriate on all neutral grasslands, such as those that have been traditionally managed as pasture (see livestock grazing). Neutral grasslands under a hay-making and aftermath regime may increase in early succession positive indicator species within 1-5 years, if there is a source of propagules nearby and there is transference of seeds between the two locations: Species that can increase within two years include oxeye daisy Leucanthemum vulgare and black knapweed Centaurea nigra; Early successional species include rosette-forming species and early successional perennials such as cat s-ear Hypochaeris radicata, red clover Trifolium pratense, bird s-foot trefoil Lotus corniculatus, yellow rattle Rhinanthus minor and self-heal Prunella vulgaris; Mid-late successional species include quaking-grass Briza media, spring-sedge Carex caryophyllea, glaucous sedge Carex flacca, cowslip Primula veris, green-winged orchid Anacamptis morio and lady s bedstraw Galium verum. Late successional species that may occur after 50 years include pepper-saxifrage Silaum silaus, common milkwort Polygala vulgaris and betony Betonica officinalis. Ancient grassland successional species that may take over 150 years include dyer s greenweed Genista tinctoria. There may be an initial negative response to cutting with an increase in tall grasses, including cock s-foot Dactylis glomerata and rough meadow grass Poa trivialis and the forb cow parsley Anthriscus sylvestris, thought to be caused by an increase in available nutrients. Grasslands abandoned more recently, have been under restoration management for a longer period of time and are close to a source of propagules may be rehabilitated more quickly than long abandoned hay meadows, grasslands that have been under restoration management for a short period of time or far away from a source of propagules. No exact timescales can be provided as the rate of rehabilitation depends on the interaction between these factors. Rehabilitation of existing priority lowland grassland 18

19 Negative Indicator Species (Key Neg) There are three types of negative indicator species that directly or indirectly impact grasslands and have a negative effect on biodiversity: Agricultural weeds, such as creeping thistle and bracken; Grass species, some that are habitat specific such as tor-grass; and Scrub vegetation, native and non-native. Agricultural weeds are plants that either indicate soil nutrient enrichment such as creeping thistle Cirsium arvense and cow parsley Anthriscus sylvestris or high levels of ground disturbance like poaching or standing water for periods of time such as docks Rumex sp. and ragwort Senecio jacobaea. A generic target is that no species or taxa should be more than occasional through the sward. Certain grass species may also be considered negative, and a generic threshold of 20% cover for coarse grasses is used for some grassland types. There are differences in species and thresholds for each type of grassland. In calcareous grassland, local targets may have been set to register an increase in cover of tor-grass Brachypodium rupestre, upright brome Bromopsis erecta and false oat-grass Arrhenatherum elatius as a potential problem. And in some cases, thresholds to register an increase solely in tor-grass may be set to monitor expansion of this invasive species. Tufted hair-grass Deschampsia cespitosa, which occurs in damp neutral grassland, can also cause problems. Management neglect, resulting in invading woody species and bracken, is also a negative indicator and there are thresholds for different types of grassland. An upper threshold of 5% invading scrub and bracken is recommended, with allowance for higher thresholds depending on site objectives. However, there are differences in the thresholds depending on the type of grassland and site-specific targets. For example, acid grassland sites can still be in favourable condition with up to 25% cover of gorse, and species-rich stands of bracken (NVC U20) could still be in favourable condition at up to 90% cover. Non-native invasive species should be absent or rare in all grasslands for example, Rhododendron sp. on lowland acid grassland. Elimination of Rhododendron from sites is desirable in view of the invasive potential of this species and its negative impacts. Bare ground can lead to invasion by negative indicator species such as creeping thistle Cirsium arvense, ragwort Senecio jacobaea and soft rush Juncus effusus. Usually, a high level of bare ground is an indicator of destructive disturbance, such as high rabbit herbivory or a high level of stocking which can lead to over-grazing, livestock poaching and trampled areas around feeding stations. Higher levels of well-disturbed bare ground may be acceptable on sites where it is a positive factor as part of the fine-scale grassland mosaic or in certain situations for example, between May and June on floodplain pasture after winter water inundation, or within certain calcareous grassland lichen communities (CG1 and CG7) where bare ground cover less than 5-10% would indicate unfavourable conditions. Lower limits for bare ground are not used, due to the difficulty of visually assessing and accurately measuring smaller amounts of this attribute. Rehabilitation of existing priority lowland grassland 19

20 Neg 1 Neg 2 Neg 3 Neg 4 Management to control problem species: creeping thistle (Cirsium arvense) (See Neg 2) common ragwort (Senecio jacobaea) (See Neg 3) tor-grass (Brachypodium rupestre) (See Neg 4) curled-leaf dock (Rumex crispus) and broad-leaved dock (R. obtusifolius) (See Neg 5) scrub management (See Neg 6) bracken control (See Neg 7) rhododendron Creeping thistle control on all types of grassland: herbicide cutting pulling/hoeing livestock trampling and grazing Common ragwort control on all types of grassland: herbicide pulling/flailing livestock grazing Tor-grass control on calcareous grassland: herbicide cutting livestock trampling and grazing Neg 5 Dock control on all types of damp grassland: herbicide cutting livestock grazing managing drainage Neg 6 Neg 7 Scrub management on all types of grassland (interim indicators focus on calcareous and neutral/calcareous grassland): cutting livestock grazing herbicide plus livestock trampling and grazing Bracken management on acid grassland (and other types of grassland where it occurs): herbicide cutting herbicide and cutting rolling and bruising livestock trampling and grazing low confidence medium confidence high confidence Rehabilitation of existing priority lowland grassland 20

21 Timescales for rhododendron control Cutting Timescales for completely eradicating rhododendron fall within 5-8 years depending on the extent of the invasive species, with another five years to monitor any re-appearance and removal of seedlings. Management is only effective after landscape-scale clearance has been achieved i.e. removal of the plant within seeding distance around and across the site. Continued monitoring is required to remove new saplings quickly after the main control programme has been completed. Timescales for creeping thistle control Herbicide Dense and patchy creeping thistle can be reduced within 1-2 years, but reduction to desired coverage is likely to take 3-4 years using a single application of herbicide a year. Herbicide treatment has been found to be an effective control method, swiftly reducing thistle cover. However, thistles can increase rapidly following cessation of spraying and return to previous levels within six years. Use of herbicide can affect non-target forbs. Herbicide control of thistles may be followed by livestock trampling and grazing which is a return to routine extensive grassland management. Cutting Cutting once a year may reduce dense and patchy thistles within 5+ years on some grasslands, but has not been found to be effective at all sites. Cutting thistles twice a year may reduce dense and patchy coverage within 1-2 years at some sites, but is more likely to occur over 3-4 years with some sites requiring over five years. Cessation of cutting management will enable thistles to return within one year. Cutting thistles may be followed by livestock trampling and grazing. Pulling/hoeing Thistles can be reduced in terms of their vigour and the number of flowering stems within two years with consecutive pulling. Pulling or hoeing thistles may be followed by livestock trampling and grazing which is a return to routine extensive grassland management. Livestock trampling and grazing Spring, autumn and winter lenient (extensive) grazing by cattle and sheep can reduce thistles within six years in lowland grasslands. Creeping thistle may not be controlled by lenient grazing at every site and certain grazing regimes can have an adverse effect, encouraging creeping thistle to spread. Herbicide treatment followed by lenient grazing is effective at controlling thistle in the longer term, keeping thistle cover low for over six years. Use of herbicide can affect non-target forbs. Rehabilitation of existing priority lowland grassland 21

22 Timescales for common ragwort control Herbicide An annual herbicide application can reduce dense and patchy ragwort within 1-2 years, but it may take 3-5+ years of annual applications at some sites. Pulling/flailing Pulling may reduce dense and patchy ragwort cover, but can take longer than three years and may not be effective. Flailing standing ragwort has been found to reduce stem density by up to 85% in a single year. Flailing ragwort may leave small cuttings strewn on grassland and these are poisonous to livestock. There is no timescale available for how long it may take the arisings to decompose. Pulling ragwort may be followed by livestock grazing. Livestock grazing Control of ragwort using sheep grazing is variable in its results. At some sites, average stocking rates can control dense and patchy ragwort within 1-2 years while at others it may take over five years if control is established at all. A combination of management of pulling and average grazing levels may control ragwort within 1-2 years. Timescales for tor-grass control Herbicide Herbicide can be effective at reducing tor-grass if applied every year for five years. Broadspectrum herbicides may affect non-target vegetation within the sprayed area and may stop re-vegetation by desirable forbs and grasses, enabling tor-grass to quickly re-invade once spraying has ceased. Graminicides may affect re-vegetation by desirable grasses. Recolonisation by tor-grass is more rapid in high-nutrient soils compared with low nutrient soils. Tor-grass can return from a single herbicide spray and reach pre-treatment cover within 3-4 years. Herbicide control of tor-grass may be followed by livestock trampling and grazing. Cutting Cutting patchy and dense tor-grass once a year in spring can be effective at reducing cover in 5+ years, but cutting twice a year in spring and early autumn can reduce patches within three years. Removing the arisings increases the success rate as the litter layer is reduced, allowing forbs to re-establish between tor-grass tussocks. Calcareous forbs can reappear within two years for example, marjoram Origanum vulgare within one year, and violets Viola sp. within 2-3 years. Recovery to calcareous grassland in favourable condition can occur within 3-4 years. Cutting tor-grass may be followed by livestock trampling and grazing. Livestock trampling and grazing Average spring cattle stocking levels can reduce dense and patchy tor-grass cover from 5+ years, but may not be effective on all sites. High spring cattle stocking levels can reduce dense and patchy tor-grass cover from 3+ years but may not be effective on all sites. Pony grazing can reduce tor-grass coverage within 1-2 years. Combinations of management interventions can see reductions in tor-grass cover within 1-4 years for example, herbicide application to new patches of tor-grass while it is in the early stages of invasion, followed by livestock grazing or cutting and grazing. Rehabilitation of existing priority lowland grassland 22

23 Timescales for controlling docks Herbicide Patchy dock cover can be reduced to the desired level by spot spraying within 1-4 years. Cutting Mechanical removal of docks is variable, and plant elimination rates vary from 0-75%. Three cuts per year can reduce the vigour of plants over two years and cutting at a height of 10cm up the stem is more effective than cutting further down the stem. Livestock grazing Grazing can be an effective method of controlling docks, with goats achieving complete eradication within four years, and sheep (East Prussian Skudden, a breed that favours eating docks) significantly reducing docks compared with cutting management within two years. The level of stocking required to control docks may need to be high to be effective and it may not be practical to graze goats on many sites. Managing drainage Managing the underlying conditions that have caused dock coverage to increase can help reduce coverage if they are resolved. For example, dock coverage can rapidly increase the year following a flood in areas where there is standing water, creating bare ground. Where there is sufficient drainage, dock coverage can be reduced swiftly within two years as the water can recede more quickly than in areas with dilapidated or reduced drainage. Timescales for rush control Herbicide If a single herbicide application is used a year, it can be successful at controlling rushes within five years. Rush may increase rapidly after spraying is stopped, and herbicide applications may harm non-target vegetation depending on application method: Dense rush cover can be reduced by weed wiping within 3-4 years. Patchy rush can be reduced in cover by spot-spraying within 3-4 years. Cutting Cutting rushes to ground level can reduce the vigour of rushes within two years if multiple cuts are taken (2-3 per year) over this period of time. Livestock grazing Intensive grazing by goats has been found to eliminate rushes within three years under high stocking levels (30 goats per hectare) and aiming for a sward height of 5-6 cm. Rehabilitation of existing priority lowland grassland 23

24 Timescales for scrub management Cutting Re-vegetation of non-target (ruderal) species happens soon after scrub removal. These species will need controlling with a combination of grazing, cutting and spraying over a period of 1-9 years. Positive indicator species can return in low numbers within three years and can reach favourable condition within 7-9 years at some sites. However, on other sites it may take longer than 10 years if there are no patches of positive indicator species that have survived within the dense scrub and there is a depleted soil seed bank. Early pioneer species on calcareous grassland include salad burnet Poterium sanguisorba, bird s-foot trefoil Lotus corniculatus and common rockrose Helianthemum nummularium. Aftercare management is required to restrict scrub re-growth. Scrub can re-establish within 2-3 years. Livestock trampling and grazing Dense scrub cover can be reduced by goats within 7-9+ years and if combined with other forms of control, such as manual clearance, this can be reduced to 4-6 years. Patchy scrub cover can be reduced by goats within 1-6 years. The timescale is shortened if manual clearance is followed by goat browsing. Goat grazing has been found to reduce scrub from 45% to 15% cover within a year on calcareous grassland with low soil nutrients. Mechanical removal followed by goat browsing may be required for effective control on sites with higher soil nutrients. Herbicide plus livestock trampling and grazing Grazing calcareous and neutral/calcareous grassland with different types of livestock at different stocking levels has been found to be effective: herbicide plus cattle grazing at a rate of LU/days/ha/yr; herbicide plus sheep grazing at 220 LU/days/ha/yr; herbicide plus sheep and goat grazing at 260 LU/days/ha/yr ; species that were found to increase within 3-5 years include hoary plantain Plantago media, dwarf thistle Cirsium acaule, daisy Bellis perennis, mouse-ear hawkweed Pilosella officinarum, dandelion Taraxacum officinalis, quaking grass Briza media, upright brome Bromopsis erecta, glaucous sedge Carex flacca, sheep s fescue Festuca ovina, bird s-foot-trefoil Lotus corniculatus, horseshoe vetch Hippocrepis comosa, salad burnet Poterium sanguisorba and white clover Trifolium repens; a negative effect is that the desirable species juniper Juniperus communis and box Buxus sempervirens can decrease; tor-grass Brachypodium rupestre may not be affected by livestock trampling and grazing due to its competitive ability. (see timescales for controlling tor-grass) Rehabilitation of existing priority lowland grassland 24

25 Timescales for bracken control Herbicide At some sites it is possible to reduce dense bracken cover to 10% (or less) within 1-6 years, and patchy bracken within 1-3 years by repeat spraying. However, it can take longer, between 4-6 years. Without further management, bracken can re-invade areas rapidly within 6-10 years. Species that may increase following control (depending on the habitat) include early hair-grass Aira praecox, spring sedge Carex caryophyllea, sheep s fescue Festuca ovina, red fescue F. rubra, field woodrush Luzula campestris, heath bedstraw Galium saxatile, tormentil Potentilla erecta and bilberry Vaccinium myrtillus. A negative trend in site condition can be identified if numbers of fronds per patch do not change or increase, frond height increases, and acid grassland and dwarf shrub heath does not show signs of re-establishment after 3-4 years. A negative indicator is tree and shrub establishment on bare ground from cleared areas. Birch can be dominant in eight years if not managed in these circumstances. (see scrub management). Cutting Cutting can reduce the vigour of the plant and, alongside other management interventions, can reduce bracken below 10% in 4-6 years. It can reduce the height of fronds by 50% in three years. Annual cutting may not be effective, but can still reduce bracken cover to 3% in years. Cutting twice a year is effective at reducing bracken cover to less than 10% within 10 years. Cutting bracken three times a year can reduce coverage within 3-6 years. Species that may increase following control (depending on the habitat) include early hair-grass Aira praecox, spring sedge Carex caryophyllea, sheep s fescue Festuca ovina, red fescue F. rubra, field woodrush Luzula campestris, heath bedstraw Galium saxatile, tormentil Potentilla erecta and bilberry Vaccinium myrtillus. If cutting is stopped within a 10-year period of commencement, bracken can recover to 80% of pre-treatment densities in 4-6 years. A negative trend in site condition can be identified if numbers of fronds per patch do not change or increase, frond height increases, and acid grassland and dwarf shrub heath does not show signs of re-establishment after 3-4 years. A negative indicator is tree and shrub establishment on bare ground from cleared areas. Birch can be dominant in eight years if not managed in these circumstances. (see scrub management). Herbicide plus cutting Herbicide plus biennial cutting can reduce bracken cover to below 10% within two years. Herbicide plus annual cutting can reduce bracken cover to below 10% within five years. Rehabilitation of existing priority lowland grassland 25

26 Rolling and bruising Bruising patchy bracken is likely to reduce frond vigour within 2-3 years, and density and coverage from 4-10 years onwards depending on the site. Bruising dense bracken is likely to reduce coverage from 4-6 years onwards depending on the site. Bruising bracken twice a year can reduce vigour of fronds within three years, and bruising once a year will reduce vigour within five years. Bracken quickly recovers once rolling stops. Species that may increase following control (depending on the habitat) include early hair-grass Aira praecox, spring sedge Carex caryophyllea, sheep s fescue Festuca ovina, red fescue F. rubra, field woodrush Luzula campestris, heath bedstraw Galium saxatile, tormentil Potentilla erecta and bilberry Vaccinium myrtillus. A negative trend in site condition can be identified if numbers of fronds per patch do not change or increase, frond height increases, and acid grassland and dwarf shrub heath does not show signs of re-establishment after 3-4 years. A negative indicator is tree and shrub establishment on bare ground from cleared areas. Birch can be dominant in eight years if not managed in these circumstances. (see scrub management). Livestock trampling and grazing Summer grazing of dense bracken is unlikely to reduce dense cover, but may reduce patchy bracken cover to suitable coverage within 4-9 years. Winter grazing of dense or patchy bracken is unlikely to reduce cover. Combinations of management interventions, such as mechanical and/or herbicide control with grazing, can reduce bracken to suitable coverage in timescales over four years. Repeated and/or additional management, including cattle grazing, can help to reduce bracken cover to suitable coverage within three years. Rehabilitation of existing priority lowland grassland 26

27 Annex Different types of grassland are present in different landscapes and are very much a product of the local environment and soils. Usually calcareous and acid grasslands are managed as pasture while neutral grasslands may be managed for hay making and aftermath grazing or as grazing pasture. There is more information on management treatments for different grassland types in the following table. Calcareous grasslands usually occur on soils derived from limestone and chalk bedrock. Calcicole plants are characteristic of this habitat, including salad burnet Poterium sanguisorba, mouse-ear hawkweed Pilosella officinarum, common rockrose Helianthemum nummularium and thyme Thymus sp., along with quaking grass Briza media, downy oat-grass Avenula pubescens, meadow oat-grass A. pratensis and yellow oat-grass Trisetum flavescens. Calcareous grassland can be the richest type of seminatural grassland, with over 40 species occurring per square metre, on the richest sites. Lowland and upland meadows are enclosed areas of unimproved neutral grassland, and can be a product of hay making and aftermath grazing or pasture management. The hydrological regime also affects the species present and some grassland types may be subject to seasonal water inundation on floodplains. Typical species of lowland meadows include oxeye daisy Leucanthemum vulgare, common knapweed Centaurea nigra, meadow vetchling Lathyrus pratensis and the annual hemi-parasitic plant yellow rattle Rhinanthus minor, while great burnet Sanguisorba officinalis is particularly a feature of floodplain meadows. Upland hay meadows may have an abundance of wood crane s-bill Geranium sylvaticum and other boreal-montane species. Acid grasslands typically occur on soils overlaying acid rocks, sands (where these are comprised of material derived from acid rock and not shell sands that are calcareous) and gravels. Calcifuge plants include sheep s-sorrel Rumex acetosella, heath milkwort Polygala serpyllifolia, tormentil Potentilla erecta, heath bedstraw Galium saxatile, wavy hair-grass Deschampsia flexuosa and velvet bent Agrostis canina. Generally, acid grasslands have a higher proportion of grasses and sedges to forbs. Acid soils may also occur on wind-blown loess and more acidic soils can occur over calcareous substrates where there is drift cover, giving rise to habitats like limestone/chalk heath, a mixture of calcicoles with heathland species such as heather Calluna vulgaris. In 2008, Natural England reported that generally, lowland semi-natural grasslands designated as Sites of Special Scientific Interest (SSSI) are in favourable or favourable recovering condition, with 90% of lowland calcareous grasslands, 73% of lowland dry acid grasslands, 78% of lowland meadows and 92% of upland meadows falling within these condition categories. Failure of favourable condition was mostly related to under-grazing, which was the major factor for 30% of lowland grassland SSSIs, and scrub encroachment which affected 18% of lowland grassland SSSIs. Upland hay meadows were affected by over-management, particularly grazing levels and excessive nutrient inputs (Natural England 2008). A sample survey of non-designated sites in 2005 found that they were not in as good condition as SSSIs, with just 28% of lowland calcareous grasslands, 23% of lowland dry acid grasslands, 18% of lowland meadows and 7% of upland hay meadows in favourable condition. Lack of positive indicator species was the most often failed attribute at non-designated sites, with cover of coarse grasses particularly affecting lowland dry acid grassland and negative indicator species affecting lowland calcareous grassland (Hewins et al. 2005). Rehabilitation of existing priority lowland grassland 27

28 Management treatments for semi-natural grassland types NVC Grassland type Livestock grazing (pasture management) Mowing and aftermath grazing (hay meadow management lowlands) Spring grazing, mowing and aftermath grazing (hay meadow management uplands) Livestock grazing with burning Sporadic management by grazing or annual mowing Sporadic disturbance as a conservation management tool Vegetation where managed rabbit activity may play a positive role in conservation management Periodic dressing of farmyard manure and lime Neutral grassland MG1 c, d, e MG2 MG3 MG4 ( ) MG5 MG8 Calcareous grassland CG1 CG2 CG3 CG4 ( ) CG5 ( ) CG6 CG7 CG8 CG9 CG10 Acid grassland U1 U3 U4 U5 ( ) The management type is not commonly applied NB Some types of grassland may be cut (to deliver conservation outcomes but not for agricultural forage) where no grazing is possible. Modified from Crofts & Jefferson (1999) by R.G. Jefferson in Rehabilitation of existing priority lowland grassland 28

29 Milestones to Recovery Project The Milestones to Recovery Project aims to capture the evidence from published literature, unpublished practical experiences and expert experience of site management to build up a simple picture of habitat recovery under a range of management interventions or combination of practices. The rates of recovery will be determined by each site s current condition, time since the commencement of the intervention, the relationship between management practices, particularly different combinations of interventions, and adverse factors that may influence condition. The objectives of the project are to prepare guidance for land managers and advisers to help them: understand where the site sits in terms of its position on a recovery trajectory; determine the likely timescales required to achieve favourable condition; decide on the most effective management intervention. The resulting information has been summarised into this advisory note. The focus of this project is on plant communities and changes to these communities following management. It fully recognises that fauna are dependent upon these plant communities and the range of niches provided. However, in terms of this project, it has not been possible to include any details of the effects of management on fauna. Rehabilitation of existing priority lowland grassland 29