A briefing document on best practice for preconstruction assessment of the impacts of onshore wind farms on birds.

Transcription

1 A briefing document on best practice for preconstruction assessment of the impacts of onshore wind farms on birds. Mike Jordan & Jon Smallie & The Endangered Wildlife Trust Wildlife & Energy Programme May 2010

2 A briefing document on best practice for pre-construction assessment of the impacts of onshore wind farms on birds. 1. Introduction Ensuring adequate assessment of the bird interests of a site The duration of bird studies recommended The area of the survey The volume of data/number of observations recommended The nature of the data to be collected Identifying birds species/groups at risk Species/taxonomic groups potentially at risk of collision Determining target/key species of significance Quantifying collision risk Assessing significance of impacts Cumulative Impact assessment References Introduction Wind-generated electricity is widely recognized to be a viable and important option for augmenting current and future energy needs. As a renewable source of energy wind power can have a lesser impact on the environment compared to many conventional energy sources, provided specific consideration is given to avoid or minimize environmental impacts. The placement and operation of wind turbines does have environmental impacts of concern to wildlife species, particularly birds and bats, and/or their habitats. It is generally recognised that in some instances, it may be concluded that a proposed project should not be constructed due to excessive and unavoidable wildlife impacts (Australia, EU, UK & USA 1 ) In the EU it is recognised that: Collision mortality (of birds) at poorly sited wind farms may have population level effects, and cumulative mortality from multiple wind installations may also contribute to population declines in susceptible species. 1 Full reference citations of documents are given at the end, but for the sake of brevity citation throughout the document is by region only. Page 1 of 21

3 And also that: There is considerable support for wind energy as an environmentally benign source of energy. Nonetheless, stringent environmental assessment is just as important for wind energy as for other developments to ensure that it is sited optimally and to avoid or at least minimise any adverse impacts. Poor quality EIAs, or lack of information, must not be permitted to lead to planning approval on the grounds of no demonstrable effect. There has been a rapid proliferation of private wind farm project applications in South Africa since the Renewable Energy Feed-in Tariff (REFIT) was announced on 31 March 2009, with an apparent rush to acquire sites and carry out the necessary environmental assessments. Globally it is clear that there are conservation concerns about the impacts that wind farms can have upon birds and that some of these impacts are very specific and unique to wind farms and require equally specific assessment in order to calculate the predicted impacts and quantify the risks. It is generally accepted that wind farms have the potential to impact upon birds both directly and indirectly, these impacts occur in three broad categories (Australia, Canada, EU, UK & USA): Displacement & disturbance Indirect habitat loss due to birds avoiding the wind farm and its surrounding area due to turbine operation and visitation/maintenance at the site. This can have a barrier effect whereby birds are deterred from using normal roosting or feeding sites. Habitat loss and & fragmentation Through direct construction activities of the wind turbines and associated infrastructure. Direct mortality Through collision or interaction with the wind turbine blades or associated structures such as meteorological masts and transmission lines. These effects must be considered over the projected operating life of the wind farm, normally years (Canada, UK & EU). These effects may also be cumulative across separate wind farms and consideration of this should be taken in the planning approval process (Australia, Canada, EU, UK & USA). The result from two or more impacts of the project (or multiple projects) may interact in a manner that produces a new impact; the loss of habitat and bird mortality due to turbine collisions may combine to have a greater impact on the viability of a particular species than when considered separately (Australia & USA). An assessment of any potential wind farm s affect on the bird interest at the site should consider thoroughly each of these three potential impacts on bird species which use or traverse the proposed site. Detailed knowledge of bird distribution and activity at the site is normally necessary in order to quantify the risks associated with the planned development. Any Environmental Impact Assessment (EIA) process for a potential wind farm should address the key question of whether the development is acceptable in terms of the likely significant effects identified. The aim of any bird surveys carried out is to provide the information which will be sufficient to enable an assessment of the potential impacts arising from ALL three effects; displacement & disturbance, habitat loss & fragmentation and direct mortality from collision. This Briefing Document draws upon accepted protocols, guidance and best practice adopted in Australia, Canada, the European Union (EU), the United Kingdom (UK) and the United States of Page 2 of 21

4 America (USA), based upon the experiences of pre and post construction monitoring & assessment of onshore wind farms. Most of these documents contain extensive bibliographies and so this briefing document has not attempted to be a primary review of literature but rather a synthesis of the already established guidance and best practice from these regions. It should be recognised that offshore wind farms have their own challenges in terms of assessment & monitoring of impacts upon birds and are generally outside the scope of this briefing document. Additionally this document focuses exclusively on assessing the pre-construction potential impacts on birds required as part of an acceptable EIA process for the consent of wind farm applications. Therefore there is no discussion of best practice with regard to assessing post-construction mortality, although this is commonly a condition of being granted planning consent in many regions (Australia, Canada, EU, UK & USA). Onshore wind farm developments have the potential to adversely affect bird populations in three main ways; displacement & disturbance, habitat loss & fragmentation, and direct mortality through collision. This briefing document discusses best practice from Australia, Canada, the EU, the UK and the USA with regard to of the potential impacts. It does not discuss offshore developments or post-construction assessment of affects. 2. Ensuring adequate assessment of the bird interests of a site Each application requires detailed and specific information to adequately assess the potential impacts of the proposed wind farm development. The USA interim guidance clearly states that; But also that: As more facilities with larger turbines are built, the cumulative effects of this rapidly growing industry may initiate or contribute to the decline of some wildlife populations. The potential harm to these populations from an additional source of mortality or adverse habitat impacts makes careful evaluation of proposed facilities essential. Due to local differences in wildlife concentration and movement patterns, habitats, area topography, facility design, and weather, each proposed development site is unique and requires detailed, individual evaluation. The extent of effects on bird population is diversified, depending mainly upon the location of the wind turbines from almost no or negligible effects on life expectancy of bird population, to significant effects with significant loss of habitats and high mortality caused by collisions. The displacement & disturbance, and habitat loss & fragmentation impacts of wind farms are in many ways though similar in nature to those experienced by some other developments (Australia & UK). Procedures and processes used as part of a normal rigorous Environmental Impact Assessment Page 3 of 21

5 (EIA) should be adequate and appropriate to assess these; in much the same way as these affects would be assessed on non-avian species. However the potential impact of direct mortality via collision is a very specific and unique impact directly associated with wind farms upon birds (growing evidence also exists for similar impacts upon bats which are not discussed within this document, but for which specific assessment is required in order to adequately assess the risk). It is the assessment of these wind farm specific impacts that the majority of this document will concentrate upon and look at the best practice currently used in other regions of the world to quantify these predicted impacts and calculate the risks. This process allows a comparative and also cumulative approach to the approval of applications for wind farms developments. If conducted pro-actively by developers it also enables micro-siting changes to be carried out at the planning stage of a wind farm that can significantly reduce the predicted impacts on birds; consequently reducing opposition to plans and increasing the chances of planning approval. Within the EU guidance states: It is clear that there is a need for robust, objective baseline studies to inform sensitive siting to minimise deleterious effects on birds, other wildlife and their habitats. It is also recognised (Australia, Canada, EU & UK) that the use of standardised methods of bird impact assessment will help to maintain consistency across assessments, facilitate comparisons between sites and assist in the prediction of effects at future developments. Despite this though, each site, and the likely impacts of a wind farm development on each site, is different. There is a general consensus that in virtually all cases baseline information has to be collected by actual observations at the proposed wind farm development site and that quantitative data on actual bird usage of the site is required to adequately assess the potential impacts. 2.1 The duration of bird studies recommended The duration of field studies to be carried out must be sufficient to allow an indication of actual bird usage of the site to be ascertained, both in terms of diversity and intensity. Hence as birds are generally highly mobile with shifting ranges across the seasons any field observations must take account of this varying utilisation pattern of the site. Additionally many birds are only present at particular sites seasonally, or only move through particular sites as part of daily movement patterns or seasonal migrations. In Canada guidance states that: Because bird activity changes throughout the year, data must be collected at the appropriate time of year, in most cases during several seasons. Nearly all sites will require data on breeding birds using the area, which usually requires surveys in May or June. Sites in areas likely to be in migration corridors may also require surveys during the spring (March May) and/or autumn (August November) migration, while some areas may require winter Page 4 of 21

6 surveys (November April). Thus, it is important that planning to collect baseline data commence at least one year in advance of any planned construction. (Note of course that the months relate to Northern Hemisphere seasons) In the USA it is accepted that: A minimum of one full year of avian use surveys is recommended following current protocols to estimate the use of the project area by avian species/groups of interest during the major migratory seasons or season of most concern. However the USA also states that: Two or more years of relevant data are recommended in the following cases: 1) risk to avian groups of concern is estimated to be high, 2) there is limited or no relevant data regarding seasonal use of the project site (e.g., data from nearby areas of similar habitat type), and/or 3) the project is significantly diverse in habitat and species. This additional avian use data should be collected to refine impact predictions and make decisions on project layout. Within the EU guidance is clear that: The EIA should include, as a minimum, a 12- month baseline field survey to determine the bird populations that use the study area during an annual cycle. The baseline data collection is also important to enable a risk assessment. Within the UK guidance states that: But also that: Fieldwork should span all periods when the target bird species are present during at least one full year. All assessments are improved by more than one year s data on bird use of a site. A typical assessment will seek to predict what the effect of the wind farm will be over, say, a period of 25 years for which consent for the wind farm is being sought. If the assessment is based on information from 1 year or 2 years only, it is vital that potential changes between years and any underlying trends should be taken into account as an integral component of the assessment. The guidance from Australia clearly states that: Counts should be made in all seasons in which the species may be present and at all times of the daily cycle and conditions in which birds might fly. In Canada guidelines utilise a risk score for assessing the level of concern category of potential wind farm developments, this utilises a desk based site sensitivity rating and the facility size to reach a level of concern category. Generic guidance is then provided on the nature and extent of baseline information and follow-up requirements for each of the four categories. Although it should be noted that for even the lowest level of concern category it states: Page 5 of 21

7 Projects in this category represent the lowest level of potential risk to birds. Usually, such projects would require some basic surveys before construction to assess bird populations within the proposed area for the turbines, and to confirm that there are not any sensitive factors that were previously overlooked. However, it is important to recognize that even basic surveys must usually be conducted over a one year period, to ensure they are done at the appropriate time of year for each species. All regions acknowledge the nature of changing bird use of habitats through the seasons and also the transient nature of bird movements, especially from feeding and roosting sites; journeys which may be long distances each day. There is a complete consensus that the duration of bird studies at a potential wind farm site must as a MINIMUM cover all of the normal variation in bird usage at the site; including breeding, wintering/nonbreeding and passage/migratory movements through the site; normally at least a minimum of one year of field observations, and generally if species of particular concern are present studies should span longer periods than a year. 2.2 The area of the survey It is important to define the area over which surveys will be conducted early in the assessment process, bearing in mind that if a larger area than finally required is surveyed, then an appropriate sub-set of data can be used for assessing potential impacts. However if extra areas are added late on in the assessment process than this may delay subsequent EIA and planning submission whilst additional data is collected for appropriate assessment. The proposed wind farm site should be regarded as the area encompassed within a line drawn around the proposed outermost turbine locations or associated structures (anemometry masts, substations, cable and grid connections and access roads). If at the time of commissioning bird survey, the precise boundary of the wind farm or even the exact site is still unknown then the proposed wind farm site should include all potential areas which may be included in the final wind farm site, so as to cover all eventualities in terms of final layout (UK). The potential impacts of a wind farm on birds extend beyond the boundaries of the wind farm site itself. Displacement effects through disturbance of birds at the nest as a result of construction activity, for example, may extend to several hundred metres beyond the wind farm site, dependent on how vulnerable the species is to disturbance. In the UK specific guidance exists on the disturbance distance of varying bird taxa. The available foraging habitat for birds which breed or roost outside of the wind farm site may also be reduced by habitat loss and displacement effects. The extent of this impact is the foraging range Page 6 of 21

8 of the species, which may be several kilometres for owls or raptors, and is typically greater than the distance at which a bird is sensitive to disturbance at the nest (UK). Surveys of breeding birds are generally undertaken to include a substantial buffer area, dependent upon the species, in the UK guidance denotes buffer distances of; 0.5 km for waders, 1 km for waterfowl & hawks, 2 km for falcons, harriers, owls, kites and 6 km for eagles. In the USA a buffer distance of 3.2 km (2 miles) is recommended for nesting raptor surveys. The impact of collision may affect birds which only visit the site whilst foraging or pass through the site en route to roosting or foraging sites. The extent to which field survey is required beyond the wind farm site should therefore be determined according to the impacts which are to be quantified. If collision risk is an issue, there will be a need for detailed observations of flight activity and behaviour at the site, these observations should cover the entire area of the wind farm site. To allow for observer error in locating flight lines, it is sensible to undertake vantage point survey within an envelope slightly larger than the wind farm site; a buffer of m is often used (UK, Australia). There is a general consensus that baseline information has to be collected from across the entire proposed wind farm site and including a buffer area dependent upon the species of concern for which data is being collected. Point observations specifically for the calculation of collision risk should cover the entire site and a small buffer to allow for observer error. 2.3 The volume of data/number of observations recommended Many guidance notes prefer to focus on the nature of the data to be collected rather than be prescriptive about the exact volume of data, or number of observations (Australia, Canada, EU & USA). Studies aim to identify the utilisation of the site by bird species considered to be target/key species of significance. This utilisation is basically the use of an area by the species expressed as quantified activity, (for the purposes of collision risk; the number of flights per unit of time and space). In Canada it is recognised that: Site-specific concerns, such as local patterns of bird use or differences in habitat must be taken into account, and depending on these circumstances, the sampling effort may need to be adjusted. There is a growing recognition of the fact that data collection must be standardised and statistically robust, yet also flexible. In Australia it is stated that: Flexibility in specifics of research design and technologies that may be used to obtain the requisite data is vital to allow for particulars of taxa and sites and to permit adaptability to emerging technologies and techniques. The most important aspect is that bird (and bat) Page 7 of 21

9 studies at various wind farm sites are quantified to standard measures and that appropriate statistical approaches and analyses are used. Whilst EU guidance states: Standardised study methods should be applied, although some site-specific or species specific sampling protocols may be necessary, e.g. on large versus small sites, targeted survey methods for some species. With regard to collecting data to assess the risk of collision then guidance from the UK and EU is more prescriptive in terms of a minimum number of observations required, this is given in an effort to standardise observations and ensure a degree of statistical robustness of assumptions used for collision risk modelling. It is recognised in the UK that the level of confidence to be sought in measures of flight activity need not be high, because collision assessments require assumptions to be made about levels of avoidance, over which as yet there are very high levels of uncertainty; therefore +/- 30% may be entirely adequate. The UK minimum guidance for observations to assess collision risks are: The recommended minimum is that 36 hours of watches should be conducted at each VP (Vantage Point) for each season (breeding, non-breeding, migratory) when the species is present. Each season should be regarded as a discrete observation period. Within each season, each part of the wind farm should be watched for at least 36 hours. If half of the proposed wind farm area has been watched for 36 hours, for example, and the other half has been watched for 36 hours (with no overlap in visibility areas), then the proposed wind farm area has been watched over for 36 hours (the time spent observing each part of the proposed wind farm), and NOT 72 hours (the total time spent in observation). Guidance on observations for calculation of collision risk in the EU is tiered dependent upon the perceived bird interests at the site; low (simplified), medium (standard), high (extended): (standard) <31-40 observations per year in accordance with the monitoring plan developed by an ornithology expert, optimally every 10 (7-14) days, possibly more often during migrations and less often during wintering periods ; For sites with low perceived bird interest this can be reduced to: (simplified) <20-30 observations per year in accordance with the monitoring plan developed by an ornithology expert ; Or for sites with perceived high bird interests (extended) observations per year in accordance with the monitoring plan developer by an ornithology expert. Page 8 of 21

10 There is no accepted standard on the exact volume of data required to be collected, but a general acceptance that this must be sufficiently robust to allow statistical analysis and that standardised methods should be developed to allow for comparisons between wind farms. Detailed guidance on the number of observations required for the calculation of collision risk is given by the UK and EU. 2.4 The nature of the data to be collected The nature of the data to be collected is very similar across all the regions. Much of the standard distributional and population data follows well established ornithological survey protocols. Many references exist on such standardised survey techniques and so this document will not discuss these. More emphasis is placed on the data requirements for the assessment of collision risk as the information required to adequately predict this is additional to that usually carried out for ornithological survey and may involve training in new skills, e.g. estimating the flight height of birds. In order to calculate predictions of collision risk, observations must be made that enable the estimation of average flight seconds per hectare, per year, at turbine risk height for each of the target species considered of concern. Standard data that contribute to measures of utilisation for particular species and sites include the following: Species list of birds occurring in and around the site. Estimated numbers and distribution of breeding birds on the site; normally expressed as breeding bird territory maps. Estimated numbers and distribution of non-breeding birds. Census or estimation of the annual maximum numbers of individuals of key species that could encounter and interact with the turbine array. Number and location of flights across the site made by target/key species; normally expressed as flightline maps showing, species, numbers, heights and durations of each flight. An estimated annual total should be extrapolated from surveys designed to document numbers of flights made within rotor-swept-height per unit time and space. Amount of available flight time per annum for target species. This must account for annual and diurnal/nocturnal cycles that affect presence at the site and/or frequency of flights. A particular focus should be given to assessments of migratory movements through the site as these may involve very large numbers of individuals which are subject to cumulative risks from a number of wind farms. Page 9 of 21

11 These data should be collected by observations spread through the day, between dawn and dusk. During the breeding season observers should pay particular attention to any breeding display flights and the flight behaviour of dispersing young as birds may be prone to collision when engaged in these activities. For water fowl observations should be collected during the period of one hour before dawn to one hour after dusk. Observations of nocturnal species can be particularly challenging and specific protocols may have to be considered if target species include owls, nightjars and other species very active at night (e.g. some waders). There are well established protocols for the collection of normal ornithological survey data, however there is a general consensus that special emphasis should be placed on the observations necessary to provide the data required to calculate predictions of collision risk. These observations are unique to the assessments of wind farm impacts and may involve special protocols and additional skills. 3. Identifying birds species/groups at risk Inherently all bird species have the potential to be impacted by wind farm developments, particularly the displacement & disturbance and habitat loss & fragmentation impacts. However it is generally recognised that some species because of their flight behaviour and/or habitat preferences are likely to be at higher risks of potentially damaging impacts from wind farm developments and especially at risk of collision. In identifying these species it must be remembered that different countries or regions will have unique endemic bird faunas and conservation priorities and so it may be inappropriate to utilise lists of at risk species from one country or region and simply apply them elsewhere. South Africa particularly with its high bird diversity and endemic species will clearly have species for which no current data exists on their vulnerability to collision with wind farms. However many of the traits that render particular species vulnerable to collision are common to the entire taxonomic group and so most regions identify at risk birds in terms of family or order groups (Australia, Canada, EU & UK), these lists are very useful in determining the South African species likely to be at risk from wind farm development. For example there is complete consensus across all regions that birds of prey are a susceptible group, even though the actual species of concern will clearly vary between Australia, North America, Europe etc. Within these at risk taxonomic groupings there may well be species which due to particular behavioural traits are rendered more or less susceptible to impacts; traits such as ranging behaviour, nocturnal flying, flight height etc. It is also the case that different types of flight, such as hovering, circling, vertical and horizontal flights made by different species of birds, and by birds engaged in different activities, may pose quite different risks of collision. Page 10 of 21

12 Determining the species that are of concern in South Africa with regard to proposed wind farm developments is a two stage process of identifying the taxonomic groups/species considered most likely to be at risk, but also identifying which species are of conservation concern or significance. These two processes derive a species list which would then be considered the target species with regard to observational data collection for the assessment of collision impacts. 3.1 Species/taxonomic groups potentially at risk of collision Guidance for most regions includes advice on the taxonomic groupings/species considered to be most susceptible to wind farm developments, or the most frequent species recorded as collisions (Australia, Canada, EU, UK & USA (partial)). The following table details all of the taxonomic groups currently considered particularly susceptible to collision impacts of wind farms, along with some indicative genera from each group and which regions consider them at risk. Taxonomic groups considered at particular risk of collision with turbines Taxonomic group (Order/Family) Regional guidance citing group as at risk Indicative genera (this is not a definitive list, JUST an indication of susceptible genera) Comments Gaviiformes - divers/loons EU, UK Gavia NB. This order does NOT occur in Africa Podicipediformes - grebes UK Podiceps Pelecaniformes pelicans, gannets & Cormorants EU, Australia Morus Pelecanus Phalacrocorax Larger pelicans and gannets considered most at risk. Ciconiiformes herons, ibises & spoonbills EU, Australia Ardea Ciconia Egretta Nycticorax Anseriformes swans, ducks & geese EU, Australia, UK Anas Cygnus Anser Aythya Particularly either migrating or dawn & dusk flying waterfowl Falconiformes birds of prey EU, Australia, Canada, UK, USA Gyps Buteo Aquila Milvus Considered highly susceptible, with large numbers of eagle, falcon and vulture collisions Page 11 of 21

13 Taxonomic group (Order/Family) Regional guidance citing group as at risk Indicative genera (this is not a definitive list, JUST an indication of susceptible genera) Comments Gypaetus Falco recorded at some wind farms. Circus Accipiter Charadriiformes gulls, terns, waders and auks EU, Australia, Canada, UK Sterna Larus Pluvialis Numenius Gulls, terns and nocturnal waders are considered particularly at risk. Strigiformes - owls EU, Australia, UK Tyto Bubo Asio Otus Nocturnal species are considered at particular risk Caprimulgiformes - nightjars Australia, UK Caprimulgus Phalaenoptilus Chordeiles Nocturnal species are considered at particular risk Gruiformes cranes, bustards & rails EU, Australia, UK, USA Grus Otus Crex Especially cranes and bustards are considered at risk. Fulica Galliformes pheasant, grouse and francolins EU, Canada, UK Tetrao Alectoris Perdix Psittaciformes - parrots Australia Neophema Lathamus Passeriformes song birds EU, Canada Emberiza Eremophila Lanius Alauda Sturnus Especially nocturnal migrants, large Passeriformes or species with display flights. Hirundo Corvus, Page 12 of 21

14 The table gives an indication of the groups likely to be susceptible to collision with wind turbines in South Africa (NB. Gaviiformes do not occur within Africa but are included as the traits they display may be useful for determining South African groups at risk) and will almost certainly be refined with further study and the construction of wind farms within South Africa. It must be remembered that there will also be additional taxonomic groups which may be susceptible but which are either infrequent or absent from the temperate Northern hemisphere (Canada, EU, UK & USA) or Australia from where the data for this table is drawn; so data on collision risk in groups such as hornbills, turacos, mousebirds etc. is completely lacking. As a general principal raptors are considered to be particularly vulnerable to collision risk as too are; any species that are not manoeuvrable in flight (e.g. species that are adapted for soaring), larger species and those active during darkness hours (Australia, EU & USA). In the Canadian guidance they produce a very definitive table of actual species involved in collisions in Canada and the USA. There is a general consensus of the broad taxonomic groups that are considered more susceptible to collision with wind turbines and the sorts of traits making species susceptible. This provides a broad baseline from which to assess South African birds and compile a preliminary list of the species deemed most susceptible to collision with turbines. 3.2 Determining target/key species of significance The list of target/key species of concern for EIA is derived from a combination of the species/groups considered to be at risk of impact and species considered to be of conservation or special concern. Hence very numerous, or introduced species may not be considered a target/key species for the purpose of EIA despite the fact that they may be vulnerable to collision at wind farms. A good example is the introduced European Starling (Sturnus vulgaris) in the USA, which is often amongst the species recorded as colliding with wind farms in the but is not considered a target species by virtue of its status in the USA. Within the UK it is recognised that: Effort in assessing impacts, and hence the target bird species for field survey, should be focussed on those species for which there is potential for an impact which might be judged significant and adverse. In most circumstances the target species should be limited to those protected species and other species of conservation concern which, as a result of their flight patterns or response behaviour, are likely to be subject to impact from wind farms. Most regions have established criteria or categories by which they assess bird species in order to determine those which would are considered significant and hence target/key species for the EIA process of wind farm developments (Australia, EU & UK). Using agreed criteria to establish the list of Page 13 of 21

15 target species allows for simpler and more regular updating of the target/key species list; as once the criteria are established and agreed then the list can be regularly and automatically updated at regular intervals as the status of species changes. In most regions these criteria comprise a combination of legal mandates and conservation listings. For example within the UK the important overarching species lists which describe protected species and species of conservation concern are: Annex 1 of the European Commission Birds Directive Schedule 1 of the Wildlife & Countryside Act 1981 Regularly occurring migratory species Red-listed Birds of Conservation Concern In addition to these criteria the UK also gives special consideration to species identified locally as of conservation concern within Local Biodiversity Action Plans, and any other species for which the site hosts a particular concentration. Also species which are the qualifying features of protected areas in the UK (SSSIs, SPAs, SACs, and Ramsar sites) are also considered as target/key species. Consequently information on the movement distances of species is important in determining whether a proposed wind farm development has the potential to affect a qualifying feature of a protected area. For example in the case of geese it is deemed that any proposed development within 40 km of a protected area designated for those geese has the potential to impact upon them. In Australia the guidance for determining key taxa states: The following criteria must be taken into account in the scoping process to determine bird and bat taxa that require impact assessment. Use of criteria here provides a process that focuses on those taxa that are important for consideration for a particular site. The following categories of taxa are of primary importance for assessment and are subsequently referred to in these Guidelines as key taxa: Taxa listed under any category of threatened conservation status (ideally using IUCN criteria) by legislation of any jurisdiction in which the site is located. Taxa that meet IUCN criteria for any category of threatened conservation status whether or not yet listed under provisions of legislation in any jurisdiction in which the site is located. Taxa listed under provisions of relevant legislation that provide protection for particular categories of taxa whether threatened or not. This includes listed international migratory and marine species. Taxa naturally occurring at low densities because of their ecological function high in the trophic order. This will primarily relate to taxa like raptors that are top-order predators. Taxa that have special cultural significance. Page 14 of 21

16 Any other taxa that regulatory authorities require to be considered for a particular site such as species not included in the categories above but for which the site is especially significant. In the EU an example of criteria used is: For the purpose of the Guidelines the species shall be deemed key species if meeting one of the following criteria: Species indicated in Article 4(1) of the Birds Directive and listed in Annex 1 to the Birds Directive Species listed in the national Red Book of Animals SPEC (Species of European Conservation Concern) category 1-3 Species included in zone protection of habitats Species with breeding density <10% (estimated in a 10 x 10 km grid) Species with national population of <1000 breeding pairs. Most regions employ fairly similar criteria to generate a list of target/key species which are then the focus of the EIA process for proposed wind farm developments. There are common features to the criteria used in most regions to identify target/key species for EIA. These criteria typically comprise a combination of species deemed to be at risk from wind farms, globally/nationally red listed species, species listed under protection in national legislation; international migratory species and species occurring at low/very low density. Such criteria could easily be applied in a South African context. 4. Quantifying collision risk Collision risk modelling is accepted as a predictive mechanism used to quantify the potential annual number of flights made by key species that are at risk of collision and may result in bird fatalities (Australia, Canada, EU, UK, and USA). It is accepted as a requirement in EIAs where target/key species occur at a proposed wind farm site (Australia, Canada, EU, UK, and USA). Inputs required to undertake such modelling include standardised bird utilisation data (generally quantified as average flight seconds per unit area (hectare), per time (year), at turbine risk height for each of the target/key species considered of concern); number and geographic layout of turbines; detailed morphometrics of the species concerned and dimensions and other parameters of turbines. The pre-requisites for an outcome measured in terms of an expected annual number of mortalities, are both the number of individuals that might interact with turbines and the estimated number of their flights that are at risk of collision. Page 15 of 21

17 Behavioural observations of birds in proposed wind farm areas before construction provide the basis of this assessment of collision risk. The estimated annual number of flights by target/key species at risk of collision are extrapolated from these observations. That is why particular emphasis is placed upon standard and replicable timed counts of bird flights undertaken at a series of locations across the site (Australia, EU & UK). Collision risk models generally take two approaches dependent upon whether birds are making regular directional flights across the proposed wind farm site; such as daily movements from feeding to roosting sites that pass through the wind farm airspace, or are resident and occupying the wind farm airspace as part of their regular territory. Well established and refined models exist for both scenarios (Australia, EU & UK) The collision risk model leads to an initial estimate of collision risk based on the theoretical assumption that birds take no avoiding action. It then becomes necessary to estimate a more realistic expectation that a proportion of birds are likely to take avoiding action successfully. These avoidance rates are species/taxonomic group specific and typically vary between 95% 99.5% (UK). Limited information on avoidance rates is available for some species, based on experience at actual wind farms. The avoidance rates for South African species would need to be refined by postconstruction studies, however avoidance rates for related species from other regions exist and are being continually refined (Australia, UK). Experiences show that normally a precautionary avoidance rate of 95% (i.e. 95% of all flights which should lead to a collision would not result in a collision) is adopted until further refinement of the actual rate becomes available (Australia & UK). Very detailed guidance upon this whole process is provided in the UK, where it is recommended that: In general, it is preferable if flight activity per unit area is calculated separately for that part of wind farm site visible from each vantage point (VP). The results should be averaged using a weighting to reflect the VP coverage, or, better, the collision risk may be calculated separately for each VP and the risk summed. This enables any particularly problematic parts of the proposed wind farm to be identified. In this way the collision risk model can be used to actually inform the proposed wind farm site layout in such a way that it may significantly reduce the impacts of collision to particular target/key species. This becomes a pro-active process between the developer and ornithological consultant in order to remodel varying iterations of the wind farm layout hopefully to achieve reduced and acceptable predicted levels of collision impact. Page 16 of 21

18 There is consensus that collision risk modelling is an accepted practice for predicting the potential number of fatalities of target/key species by proposed wind farm developments. Further it is a useful tool for informing the proposed site layout and refining turbine locations. Accepted models exist that could be used and precautionary avoidance rates, or those of related species, could be utilised whilst those of South African species are determined by post-construction studies. 5. Assessing significance of impacts In all regions (Australia, Canada, EU, UK and USA) importance is attached to actually assessing the level of significance of predicted impacts, rather than just whether or not an impact is predicted. Assessing the significance of any predicted impacts is not always a simple process and normally requires knowledge of population information and conservation status of the species in question. In the EU it is considered that: A well designed project should not result in loss of valuable habitat or adverse impact on protected species. In Australia it is recognised that: There are two distinct values that can be placed on any impact on birds (or bats). Both may be valid but it is vital to have clarity about the two concepts and to distinguish them. The first is the purely biological effect on the functioning of a bird (or bat) population. The second is the level of community and political.acceptability of the impact. The latter may be subjective and indefinable and some iconic species clearly rate higher than others in public perception. This measure is a reality and should not be ignored in decision-making. In the UK and EU much emphasis is placed upon maintaining the favourable conservation status of the species in question. It is viewed that an impact should be judged as of concern where it adversely affects the favourable conservation status of a species, or stops a recovering species from reaching favourable conservation status, at international, national or regional level. This places particular emphasis upon any adverse impact to a species which is already deemed to be in unfavourable conservation status and declining. Conservation status is considered favourable where; population dynamics indicate that the species is maintaining itself on a long-term basis as a viable component of its habitats; and the natural range of the species is not being reduced, nor is likely to be reduced for the foreseeable future; and Page 17 of 21

19 there is (and will probably continue to be) a sufficiently large habitat to maintain its populations on a long-term basis. In Australia too it is recognised that: An artificially increased mortality rate could be deleterious and deaths may be of much greater importance for populations already in decline due to other cause. Nevertheless assessing the significance can be difficult to make formulaic in best practice guidelines, and whilst most EIA regulations adequately provide guidance on assessing significance to loss of habitats and/or small sedentary populations as one off event caused by development; wind farms and birds can present additional challenges. Collision mortality may be an ongoing impact for the entire operational life of the wind farm and if affecting wide ranging species then may have the potential to adversely affect whole regional, national or international populations of a species. In the UK guidance states that: Judgement will depend on the conservation status and sensitivity of the species and its supporting habitats, its abundance in the area, any special ecological role fulfilled by the site in question, and the robustness of the population in the face of losses. And that in assessing significance: An impact should be judged as of concern where it would adversely affect the favourable conservation status of a species, or stop a recovering species from reaching favourable conservation status, at international or national level or regionally. In Australia detailed discussion is given to trying to answer the questions necessary to assess the significance of impacts, they consider that: Significance will also depend on the receptor of the impact in this case the bird species affected (their population size, distribution, range, reproduction strategy, lifespan, etc). It is important that these attributes are considered in assessing the significance of an impact and described as fully as possible in the Environmental Statement. Increasingly some form of population prediction is being used in order to help overcome these issues of having to assess the significance of an ongoing impact that may have the potential affect large cohorts of the population (Australia, EU & UK). It is recognised in the EU that: Population models provide a means of predicting whether or not there are likely to be population level impacts arising from collision mortality. Population Viability Analysis (PVA) is an appropriate mechanism to model and predict the effects in terms of altered extinction probability for the population. It is particularly effective for considering cumulative impacts on the population as whole from a number of planned and/or operational wind farms. However, demographic parameters which are pre-requisites of PVA are not always well known for many taxa and some informed assumptions will usually be integral to this component. It is a particularly valuable process for highlighting sensitive parameters, e.g. even small levels of increased adult mortality in long-lived slow breeding species may have a long-term significant Page 18 of 21

20 adverse affect on the population, whereas the population may be much more robust to juvenile and sub-adult mortality. In the USA guidance dictates that even species formerly occupying areas but now extirpated my need to be considered when assessing potential significant impacts; it is noted that: From a wildlife conservation perspective, a species in decline may be absent from an area with specific consideration to avoid or minimize environmental impacts it formerly occupied, yet the habitat remains important for the conservation or recovery of that species. Assessing the significance of impacts on birds on an individual basis for each separate wind farm application has limited value if a number of applications exist all within the same population of birds in question. Whilst each EIA must be expected to assess the significance of impacts of the proposed development for which it is submitted it is recognised that an overarching cumulative assessment may be required in order make a planning decision on applications (Australia, Canada, EU, UK & USA). There is general consensus that merely predicting whether or not an impact will occur is insufficient. Assessing the actual significance of predicted impacts is critical to the planning approval/refusal process. This presents particular challenges for wind farms and birds where the impacts may be ongoing for the entire operational life of the wind farm and also affecting large wide ranging populations. Increasingly PVA is used to put these impacts into perspective. 6. Cumulative Impact assessment With a rapidly growing number of wind farm applications in South Africa and additionally in other regions of the world a growing number of consented and operational wind farms there is now a general consensus that assessing the impacts for each wind farm in isolation does not adequately assess the true significance of the impacts for bird populations (Australia, Canada, EU, UK & USA). Highly mobile species may have the potential to interact with a number of wind farms as part of their daily or seasonal movements. Therefore several wind farms each with an impact level deemed not significant may in combination exert a significant adverse affect on the population of a bird species. In Australia it is clearly stated that: Significance of effect cannot be judged only on an individual project basis. Whilst displacement and collision mortality may or may not be detrimental at a site level, cumulatively with other projects they may lead to a population level impact. Whilst EU guidance recommends that: Page 19 of 21

21 If there are any other projects (other wind farms or other developments) which have been developed or are being proposed in the area, then the EIA must take into account any cumulative effects on birds that may arise from the wind farm development in conjunction with these other projects. This area of wind farm EIAs is often inadequately covered, partly due to a lack of clarity concerning whose responsibility it is to carry out such cumulative impact assessments. Statutory agencies are in some cases insisting upon developers to provide a cumulative impact assessment (often involving wind farms being developed by different developers) and in some case an associated PVA to demonstrate significance (Australia, UK). The scale of this cumulative assessment must be biologically relevant to the target/key species and population in question. This can be particularly challenging for species involved in large scale migrations where the whole population may potentially be susceptible to impacts from many wind farms widely spaced apart. Under such circumstances it may be appropriate to carry out full Population & Habitat Viability Analysis (PHVA) for the species in order to evaluate sensitivities and acceptable levels of increased mortality across the whole range of the species. There is no generally accepted process for carrying out cumulative impact assessment, although the process is discussed at length in guidance from Australia and the UK. At its simplest it may involve addition of quantitative impacts, such as habitat loss areas or predicted numbers of collisions; however the relationship may not be simply additive in all cases, especially predicted numbers of collisions. There may also be thresholds above which the factor of the additive impact increases making the impact much more severely adverse. One of the benefits of standardising data collection methodologies and collision risk modelling is that it may facilitate easier cumulative impact assessment. Standard measures allow utilisation rates to be compared between sites and to be combined for the purposes of assessing cumulative impacts of multiple wind farms (Australia, EU & UK). There is a general consensus that assessing the impacts for each wind farm in isolation does not adequately assess the true significance of the impacts for bird populations. Greater attention needs to be placed on assessing the cumulative impacts of all operational, consented or planned wind farms (and other relevant developments) on target/key bird species. In some cases insignificant impacts at individual wind farms will accumulate across all wind farm developments to have a significant adverse impact upon birds. Page 20 of 21