POSTER ABSTRACTS | CONTENTS | ABSTRACTS
Managing vegetation structure to benefit Kestrels
1 Newcastle University, School of Biology, Ridley Building, Claremont Road, Newcastle, NE1 7RU
2 Natural England, Northminster House, Peterborough, PE1 1UA, UK
Kestrel Falco tinnunculus populations have declined in Britain by 19% since 1994 and are also declining in other parts of Europe (Raven et al. 2005; Hagemejer & Blair 1997). For this reason, the species is regarded as of conservation concern in both a UK and European context (Gregory et al. 2002: BirdLife International 2004). The declines have been largely attributed to the adverse effects of agricultural intensification on farmland habitats and on populations of small mammals, particularly voles (Microtus spp.) which are the major prey of kestrels (Hagemejer & Blair 1997).
Agri-environment schemes have resulted in large amounts of grassland, in the form of grass margins, being created in the British countryside: in England, for example, over 25,000 hectares of grass margins were created through agri-environment agreements prior to the launch of the Entry-level Scheme (ELS) in 2005 (Defra stats). Despite this increase in potentially suitable habitat, British kestrel populations have continued to decline. Foraging theory predicts that it is not prey abundance but availability that determines where predators hunt (Stephens & Krebs 1986). Thus shorter grass (or patches of bare ground) may enhance foraging by kestrels by providing greater accessibility. However, in the absence of adequate cover, prey animals are likely to disperse to areas where they are less accessible (Hansson 1977). Grasslands are a valuable resource for voles, providing both food and cover/protection from predators (Ostfeld 1985). A recent small-scale study of three Kestrel pairs in Switzerland suggested that a combination of both short and longer grass may benefit kestrel foraging (Aschwanden et al. 2005).
AIMS
1. To examine habitat preferences by Kestrels on farmland at various times of the year by measuring the distribution of foraging birds relative to habitat availability.
2. To relate foraging behaviour at different distances from the nest to prey type.
3. To manipulate vegetation height (probably by mowing) to investigate the temporal and spatial effects on Field Vole Microtus agrestis distribution.
4. Relate vegetation management to kestrel productivity.
In the poster we will present preliminary data from 7 pairs for aim 1) and describe plans for aims 3) and 4).
Claudia Garratt is in her first year of a PhD at Newcastle University looking into the ecology of Kestrels on farmland. She completed a Zoology BSc at Newcastle in 2008, gaining First Class honours. She has previously worked on navigation behaviour in bumblebees, and assisted with herpetology surveys in Borneo.
The Farm4Bio project: maximising the potential of uncropped land
John Holland*1, Ian Henderson2, Jim Orson3 & Jonathan Storkey4
1 Game & Wildlife Conservation Trust, Fordingbridge, Hampshire, SP6 1EF, UK
2 British Trust for Ornithology, Thetford, Norfolk IP24 2PU, UK
3The Arable Group Ltd, Morley Business Centre, Deopham Road, Morley, Wymondham, Norfolk, NR18 9DF, UK
4Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
* Email: jholland@gct.org.uk
The overriding aim of the Farm4bio project is to determine whether management of uncropped land for biodiversity on conventional arable farms can achieve significant and measurable increases in biodiversity, that are at least equivalent to those attained on organic farms with a primarily arable cropping system. Yet the project goes further and will address three further fundamental questions concerning the management of farmland for wildlife. These are: 1) are there relationships between the proportion of uncropped land and levels of biodiversity? 2) does active management compared to farm management lead to higher levels of biodiversity? 3) how should this land be arranged in the landscape?
Baseline monitoring started in 2006 across 100 ha blocks on 24 arable farms split equally between two regions (Eastern and Southern England). The treatments are 1.5 or 6.0 ha of land either specifically managed for biodiversity or managed by the farm, and these are distributed either in strips or blocks. These are compared to four organically managed blocks. The habitats developed for biodiversity were established adjacent to each other and include wildbird cover, insect rich cover, floristically enhanced grass and natural regeneration. Levels of biodiversity are determined through measurements of farmland birds, mammals, insects and plants. Birds were mapped across the whole block in April, May and June.
To investigate the effects of landscape complexity, land use within the blocks and in the surrounding 3x3 km was classified into uncropped and cropped categories. Year, region and farm along with habitat, cropping and landscape variables were all included in an analysis of the first three years data (two baseline and one treatment year) using General Linear Modelling. No relationship was established between the area of uncropped land and the diversity of bird species. However the numbers of birds seem to be responsive to the proportion, distribution and management of uncropped land:
· There is a variation in the response of individual species that appears to be explained by preferences for food source and habitat
· There seems to be a minimum requirement of a total of 2% of uncropped land in order to ensure the presence of some key farmland species
· A very preliminary analysis of the data collected so far suggests that there is a preference for large blocks of managed uncropped land rather than sown strips at the edge of fields
John Holland is Head of Farmland Ecology at the Game & Wildlife Conservation Trust and lead scientist for the Farm4Bio project. His research focuses on investigating the causes behind the declines in farmland wildlife and then developing practical farm management techniques to resolve any problems.
Effects of wildlife conservation efforts on a declining farmland bird, the grey partridge, and farmland biodiversity
Annelie M. Jönsson*1, Nicholas J. Aebischer2 , Ola Olsson1 & Henrik G. Smith1
1 Animal Ecology, Ecological Institution, Lund University, 223 62 Lund, Sweden
2 Game & Wildlife Conservation Trust, Fordingbridge, Hampshire, SP6 1EF, UK
* Email: Annelie.Jonsson@zooekol.lu.se
The European population of Grey Partridges Perdix perdix has been declining since the mid 20th century. Much research points at the agricultural intensification as the major reason. However, this process consists of several different parts of which some may be more important. The importance of these parts might also differ between different parts of Europe. This project aims to clarify the situation for the Grey Partridge in Scania, the southernmost county of Sweden.
Bag records, agricultural statistics and aerial photographs will be used in an attempt to explain the reasons behind the decline of Grey Partridges in Scania. The current presence of partridges will be related to variations in today’s agricultural landscape as well as amounts of EU-subsidies. A large-scale experiment will investigate the effects of improving and recreating Grey Partridge habitats on a number of larger Scanian estates.
The results will be used to influence future agricultural subsidy schemes.
Annelie Jönsson is a PhD student in her first year at the Ecological Department at Lund University. Her main research interests are conservation biology, ecology and wildlife management.
Farmland bird abundance and diversity as explained by land use intensity and landscape structure
Ola Olsson, Anna S. Persson. Sören Svensson, Maj Rundlöf, Martin Stjernman & Henrik G. Smith
Department of Animal Ecology, Lund University
Ecology Building, SE-223 62 Lund, Sweden
We show here that the abundance, diversity and distribution of farmland birds can be well explained by landscape variables related to land use intensity and landscape structure. The birds were 28 species of fairly common breeding farmland birds in southern Sweden. Occupied breeding territories of these were mapped in 136 different 1x1 km square landscapes regularly dispersed through the county of Scania in southernmost Sweden. In the same landscapes we performed a GIS analysis of land use and landscape structures. We used a GIS-database from the Swedish Board of Agriculture (SBA) in which all agricultural fields are mapped with information on their crops. This was complemented by digitizing semi-natural habitats such as tree rows and field margins. In addition we acquired, from Statistics Sweden, the standard yield of spring barley in 17 districts in the county. Using factor analysis, these landscape variables were combined into 5 factors that together explained 78% of the variation among the variables. The factors were, in order of importance, L1: land use intensity; L2: landscape structure; L3: amount of pasture; L4: amount of ley grass; L5: crop diversity. Species richness and Simpson diversity was non-linearly related to land use intensity (L1), with a maximum at moderate intensities. In a multiple regression analysis factors L1-L5 explained significantly species richness (r2=0.33), the Simpson diversity (r2=0.18) and the abundance (r2=0.13) of all farmland birds. Land use intensity and landscape structure were the strongest predictors. Considering individual species of birds, the landscape factors significantly influenced the abundance of nearly all. The amount of variance explained by all factors together was in the range 30-60% for Starling, Meadow Pipit, Tree Pipit, Skylark and Yellowhammer and in the range 20 – 30% for Pheasant, Grey Partridge, Red Backed Shrike, White Wagtail, Wheatear, Whinchat, Linnet, House Sparrow and Tree Sparrow. Other species were less explained by the landscape factors. An ordination of the bird community (constrained correspondence analysis) showed how different bird species were related to the landscape variables. For example Skylark, Grey Partridge and House Sparrow were clustered around variables indicating intensity, whereas for example Whinchat and Wheatear were more connected to pasture. The results of this study will be used as predictions for a new study of the farmland birds in a different set of landscapes.
Ola Olsson is researching biodiversity and conservation in the agricultural landscape. He is currently coordinating a multidisciplinary project (ecology-economy-physical geography) that studies the cost-effectiveness of agri-environment schemes for conserving biodiversity and promoting ecosystem services. Before he managed the reintroduction of white storks, and has done research on Lesser Spotted Woodpeckers.
Differing impact of the Austrian agri-environmental scheme on bird diversity in arable land and grassland
Stefan Schindler*1, Martin Pollheimer1,2, Johannes Peterseil1,3, Ingrid Schmitzberger1,2
& Thomas Wrbka1
1 Department of Conservation Biology, Vegetation- & Landscape Ecology, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
2 coopNATURA, Consulting Engineers for Ecology and Nature Conservation, Kremstalstrasse 77,
A-3500 Krems an der Donau, Austria
3 Austrian Environmental Protection Agency, Spittelauer Lände 5, 1090 Vienna, Austria
* Email: stefan.schindler@univie.ac.at
Counteracting the negative impact of industrialized agriculture by providing subsidies to farmers for environmentally friendly agricultural practices, agri-environmental measures (AEM) are the most important policy instruments to protect European biodiversity in agricultural landscapes. To assess the environmental effects of the Austrian AEM, we mapped landscapes and surveyed birds in 2003. The ten sampling areas of 3 km² were located in the three most important types of Austrian agricultural landscape, i.e., grassland in alpine valleys and basins, mixed agriculture in mountain areas, and eastern arable land. We investigated the AEM in a parcel-wise manner and analyzed their effects on bird diversity. All bird observations were recorded with a high degree of spatial precision and related to the investigated field parcels. Bird species were then classified into character guilds based on their breeding strategy and according to their vulnerability status, i.e., Red List Austria and Species of European Conservation Concern. Special focus was given to the character guilds of ground breeders, e.g., Grey Partridge (Perdix perdix), Eurasian Skylark, Whinchat (Saxicola rubetra), breeders within the herb layer, e.g., Marsh Warbler (Acrocephalus palustris), Reed Bunting (Emberiza schoeniclus), and breeders within small remnants of reed, e.g., Common Grasshopper-Warbler (Locustella naevia), and Sedge Warbler (Acrocephalus schoenobaenus). These communities should serve as good indicators as they are heavily affected by agricultural treatment (e.g., mowing, harvesting). Densities of bird individuals on parcels with and without AEM in 2003 were compared using Mann-Whitney U-tests.
The results suggested that the effects of AEM on bird diversity were generally stronger in arable fields. There, even the less specific “reduction measures” led to significantly higher densities of ground breeders and endangered species. The effects of the specific conservation measures were clear, although sometimes not statistically significant due to the very low number of parcels that participated in these measures. In grasslands, the AEM were much less effective. One explanation is that characteristic grassland species such as Whinchat, Common Grasshopper-Warbler and Marsh Warbler normally breed rather late in May and June. Thus, first mowing of grasslands delayed by the reduction measure to May, is not postponed enough, and such measures could also lead to ecological traps, providing grasslands which appear attractive to birds initially, but which are ultimately unsuitable for successful breeding. The only AEMs that clearly promoted the investigated grassland bird communities are bundled to “Specific habitat conservation measures for bird habitat”. But these very specific measures have such limited coverage that they cannot guarantee the continuous survival of populations. However, the few parcels with such measures indicate strong positive effects towards sustainable agriculture, and as targeted measures that directly address threatened species were most effective, we highly recommend that increased participation of farmers in these measures should be encouraged.
Stefan Schindler is PhD student and research assistant at the Department for Conservation Biology, Vegetation- and Landscape Ecology at the University of Vienna (Austria). He is investigating the links between landscape structure and biodiversity, is expert in birds of preys and in conservation management in both, forest and agricultural landscapes.
Predation risks on bird nests in fragmented suburban landscape
Petr Suvorov*1,2, Monika Pětníková1 & Miroslav Šálek1
1 Czech University of Life Sciences, Faculty of Environmental Science, Kamýcká 129,
Prague 6, Czech Republic
2 Zoological Garden of Prague, U Trojského zámku 3/120, Prague 7, Czech Republic
* Email: suvorov@fzp.czu.cz
The influence of landscape fragmentation on bird populations is a frequently discussed ecological theme. Fragmentation divides the landscape to smaller habitat patches which can create isolated islands. A fragmented landscape can provide a higher supply of resources for birds (food, nesting places, refuges, etc.), but also benefit nest predators–generalists from the surrounding landscape, resulting in increased nest predation. Higher nest predation at the boundary of the fragment and the adjacent habitat can induce edge effect. With decreasing fragment area, the predators can also penetrate deeper into the fragment and extend the edge effect. If the birds are attracted to these habitats with more resources, they can suffer from the ecological trap.
The main aim of this study was to test whether the nest predation (1) increases with decreasing area of unmanaged herbaceous patches (idle fields) frequently dispersed as fragments of different sizes across the agricultural landscape in suburban zone of Prague and (2) is influenced by the heterogeneity of the surrounding landscape.
Fifty-three idle fields spaced a minimum distance of 1000m apart in each were selected. Pairs of artificial nests were baited with two hen eggs (one fresh and one wax-filled) were installed in each study area (one nest at the immediate edge, one nest in central position). Presence (tracks, droppings, food remains etc.) of potential nest predators was monitored in 28 selected plots.
Total nest predation rate achieved 65.1% (31 predated nests in edge habitat and 38 in the interior). Forty eggs (42.4%) had the marks indicating predation by birds (65.1%) or mammals (30.2%). Nest predation rate was not significantly influenced either by fragment area or by heterogeneity of surrounding landscape. Edge effect was not detected but our results indicate increased nest predation in the fragments situated in more heterogeneous agricultural landscape.
Petr Suvorov currently does his post-graduate study on Faculty of Environmental Science. His main interest is how fragmentation of landscape influences birds´ populations and nest predation rate. He also works as an external collaborator of the Education Center of Zoo Praha.
Is the decline of the House Sparrow caused by reduced farmland heterogeneity
Maria von Post*, Ola Olsson, Martin Stjernman, & Henrik G. Smith
Lund University; Ecological Institution, Department of Animal Ecology,
Ecology building, SE-22362 Lund, Sweden
* Email: maria_von.Post@zooekol.lu.se
Swedish farmland bird populations have declined for decades, reflecting similar trends throughout northern Europe. These declines have been attributed to agricultural intensification. The House Sparrow Passer domesticus, is one of the most affected species, and has declined by more than 50 % in Sweden during the last decades. It is a non-migratory bird, feeding on seeds and weed except during the breeding season when they feed their nestlings mostly insects. The House Sparrow is strongly connected to the human community resulting in dependency on food resources and nesting cavities, non-purposely created by humans. The change in farming and building techniques, pesticide use, landscape changes, and several other aspects connected to our cultural development during the last decades has had an immediate effect on the House Sparrows ability to thrive. The population decline occurs in both urban and rural habitats but probably due to different causes. This study will focus on the decline in the agricultural landscape and the causes connected to this habitat.
We are now establishing colonies of House Sparrows on farms in landscapes with different values of heterogeneity. We will monitor these colonies and collect data on the aspects that influence population demographics. We will report results from the first field season.
Maria von Post is a PhD student at Lund University, Sweden. Her PhD project aims at investigating the population ecology of House Sparrows in the agricultural landscape, and how its decline is connected to loss of heterogeneity.
