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Society for Conservation Biology: 2002 Annual Meeting

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Society for Conservation Biology: 2002 Annual Meeting


Society for Conservation Biology 16th Annual Meeting July 14-July 19 2002
co-hosted by DICE and the British Ecological Society


Abstracts for Conservation and Birds
Session One

Wednesday 17th July, 10.15 - 12.15, Eliot Lecture Theatre 2

Chair: Szabolcs Lengyel




(BLOCK CAPITALS indicate the presenting author)

10.15 - 10.30
LENGYEL, SZABOLCS. Department of Evolutionary Zoology and Human Biology, University of Debrecen, 4032 Debrecen, Egyetem tér 1., Hungary.

ENHANCING BREEDING SUCCESS IN PIED AVOCETS UNDER DENSITY-DEPENDENT PREDATION

Pied Avocets (Recurvirostra avosetta) were studied on alkaline lakes in central Hungary between 1998 and 2000 to understand how information on reproduction and sociality can be used to enhance breeding success. Because the most important factor limiting breeding success was high mortality of young (<1 week-old) chicks by predation, I experimentally tested the effect of clutch and brood size on the number of fledglings produced. Augmentation of clutches by extra eggs resulted in a higher number of hatchlings, however, the number of fledglings did not increase, possibly due to the exhaustion of parents incubating supernormal clutches. The number of fledglings, however, was higher in broods enlarged by an extra chick immediately after hatching than in control broods under high predation. The costs of incubating large clutches and the benefits of larger broods can explain why many pairs adopt young alien chicks soon after hatching. Thus, an optimal conservation strategy to enhance breeding success can be to exploit the parents’ willingness to adopt and to increase brood size with chicks hatched artificially from eggs collected in risk-prone areas. This study exemplifies that an understanding of the reproductive and the social system is important in designing conservation measures.

10.30 - 10.45
Confer, John, JEFFERY LARKIN, Paul Allen, and David Maehr. Biology Department, Ithaca College, Ithaca, NY 14850, USA (JC), Department of Forestry, University of Kentucky, Lexington, KY 40546, USA,< jllark0@pop.uky.edu> (JL), Cornell Lab of Ornithology, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA (PA), Department of Forestry, University of Kentucky, Lexington, KY 40546, USA (DM).

EFFECTS OF VEGETATION, INTERSPECIFIC COMPETITION, AND BROOD PARASITISM ON GOLDEN-WINGED WARBLER NESTING SUCCESS

The recent decline of the golden-winged warbler, Vermivora chrysoptera, (GWWA) correlates with loss of nesting habitat, range expansion of the blue-winged warbler, V. pinus, and eastward expansion of the brown-headed cowbird, Molothrus ater. Multivariate statistics were used to examine the effects of these factors on GWWA reproduction in northcentral New York. We monitored 69 GWWA nests, and quantified various territorial attributes associated with these nests. Tree and herb cover negatively influenced the number of GWWA fledglings. Blue-winged warbler proximity had a strong, negative effect on GWWA clutch size. Herbaceous cover positively influenced the number of cowbird eggs in GWWA nests. Cowbird parasitism reduced the number of GWWA eggs incubated and the proportion of incubated GWWA eggs that hatched. However, cowbird parasitism did not reduce nestling success rate. Cowbirds parasitised 30% of GWWA nests, and reduced the number of GWWA fledged by about 17%. Herb and tree cover in GWWA territories reflected earlier plant succession than cover in blue-winged warbler territories. The negative effect of blue-winged warbler proximity is likely less in the earliest stages of succession used by GWWA. This habitat might provide optimal GWWA nesting conditions if local cowbird abundance is low.



10.45 - 11.00
CURSON, DAVID R. and Nancy E. Mathews. Department of Wildlife Ecology, UW-Madison, 226 Russell Labs, 1630 Linden Drive, Madison, WI 53706, USA, <curson@calshp.cals.wisc.edu>.

AN EDGE EFFECT AT THE LANDSCAPE SCALE – TRADE-OFFS BETWEEN COMMUTING AND EGG PRODUCTION IN PARASITIC COWBIRDS

Brood parasitism by Brown-headed Cowbirds is a harmful edge effect associated with habitat fragmentation, which currently threatens populations of certain endangered songbird species in North America. Cowbirds frequently exhibit a pattern of daily commuting between forested breeding areas and open habitats, upon which they depend for feeding. In certain landscape conditions they are known to commute up to 13 km each way on a daily basis, thus penetrating deep into the forest interior. Because the estimated energetic cost of a 20 km flight for a cowbird is 60% of the energetic cost of producing an egg, a trade-off between these two energy demands is expected. We measured the rate of cowbird egg production in long-distance commuters (LDCs; >10 km each way) and short distance commuters (SDCs; <2 km each way) at a major prairie-forest interface in northeastern New Mexico, from counts of post-ovulatory follicles in dissected ovaries. LDC’s laid 50% fewer eggs over a five day period than did SDCs. These results suggest that although cowbird management may have to consider, under certain circumstances, a larger scale than previously realised, the impacts of individual cowbirds on hosts may decline as commuting distance increases.


11.00 - 11.15
WARD, MICHAEL, Scott Schlossberg, Department of Animal Biology, University of Illinois, Urbana - Champaign, IL 61820 USA, <mpward@students.uiuc.edu> (MW), Program in Ecology and Evolutionary Biology, University of Illinois, Urbana - Champaign, IL 61820, USA (SS)

USING CONSPECIFIC ATTRACTION TO CONSERVE AN ENDANGERED SONGBIRD

Conserving vagile animals such as birds is often difficult because the animals may choose to settle on private lands or areas designated for uses incompatible with conservation of the species. If managers could attract birds to predetermined sites known to be high quality, this would be a major benefit. We tested whether conspecific attraction, the tendency for species to settle near individuals of the same species, could be used to attract the black-capped vireo (Vireo atricapillus) to previously unoccupied habitats. The vireo is an endangered songbird threatened by brood parasitism from brown-headed cowbirds (Molothrus ater). We played taped vocalizations of vireos in previously unoccupied habitat during the period when vireos were migrating to the breeding grounds. We were successful in attracting 73 vireos to settle at five experimental sites, while no vireos settled on two control sites where no vocalizations were played. Birds attracted to experimental sites experienced high nesting success (42%) and low cowbird parasitism rates (7%) relative to a nearby, established population. The success of our experiment suggests that conspecific attraction could be an important conservation tool, allowing managers to more effectively and efficiently manage endangered birds.



11.15 - 11.30
SEHGAL, RAVINDER N. M., Hugh I. Jones, and Thomas B. Smith. Center for Tropical Research, Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA 94132 USA (sehgal@sfsu.edu) (RNMS), Dept. of Microbiology, University of Western Australia, Nedlands, Australia (HIJ), and Institute of the Environment, University of California Los Angeles, Los Angeles CA 90095 USA (TBS).

HOST SPECIFICITY AND PREVALENCE OF BLOOD PARASITES IN AFRICAN RAINFOREST BIRDS; CONSERVATION PERSPECTIVES FROM A MOLECULAR APPROACH.


Here we employ molecular techniques to determine the incidence and study the host-specificity of four different parasites in the African rainforest avifauna. The four blood parasites studied here are Plasmodium and Haemoproteus, which cause avian malaria, Trypanosoma, and microfilarial nematodes. We developed polymerase chain reaction (PCR)-based diagnostic tests to amplify parasite-specific genes from avian blood samples. We use these tests to describe the incidence of these parasites within over seventy bird species in rainforest habitats of Cameroon, the Ivory Coast and Equatorial Guinea. In addition, by sequencing the gene products, we determine phylogenetic relationships between individual bird species and their parasites. For example, in Trypanosoma, we found little trypanosome-lineage specificity across either avian hosts or geographic locations. We found that birds from different habitats, collected over a wide distance range, were infected with a single haplotype, and several haplotypes could be detected at a single location. On the other hand, with nematode microfilaria, we found one bird species, the Fire-crested Alethe, (Alethe castanea) was particularly prone to this parasite, and the parasite exhibits a high degree of host- but not geographic specificity. We discuss the possible ecological and conservation implications of these host-parasite interactions.



11.30 - 11.45
Dowell, Simon, PETER GARSON, Dai Bo and He Fen-qi. School of Biological and Earth Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK, <s.d.dowell@livjm.ac.uk> (SD), Department of Agricultural & Environmental Sciences, University of Newcastle-upon-Tyne, NE1 7RU, UK (PG), Wildlife Conservation Division, Sichuan Forestry Department, 15, Renminbeilu Road, Chengdu, Sichuan, China (DB) and Institute of Zoology, Academia Sinica, 19, Zhongguancun Lu, Beijing, China (HFQ).

USING THREATENED BIRDS AS FLAGSHIPS FOR CONSERVATION IN SICHUAN, CHINA

The broadleaf forests of the Daliang Shan region in southern Sichuan have been identified by Birdlife International as areas of significant avian endemicity. The endangered Sichuan Partridge, Arborophila rufipectus, is confined to this area and has been the subject of surveys and detailed research since 1996. Our survey work has allowed detailed mapping of its distribution and estimates of population density all of which reveal fewer than 0.8 territorial males per km2, a reduction on previous estimates from the early 1990s. Radio telemetry has shown statistically significant preferences for mature primary and secondary forest habitat over scrub and sparse woodland. This, along with survey results on other endemic birds, has led to recommendations being made in relation to forest protection and management. As a first step, the Sichuan Forestry Department has designated a new protected area at Laojunshan, within the range of the Sichuan Partridge. We are using this to experiment with conservation management methods that aim to benefit Sichuan Partridge and other endemic birds as well as the local people.



11.45 - 12.00
NICHOLLS, MIKE and Chris Eastham. Ecology Research Group, Canterbury Christ Church University College, Canterbury CT1 1QU, UK, <mkn1@cant.ac.uk>.

GEOGRAPHIC VARIATION OF THE SAKER (FALCO CHERRUG) AND IMPLICATIONS FOR CONSERVATION

The saker, Falco cherrug, has a wide Eurasian distribution and is a traditional and valued bird of Arabic falconry. Annually, large numbers of these falcons are trapped on migration to wintering grounds for falconry and we present data which, superficially at least, suggests that this practice is sustainable. However, it may be that not all subpopulations are equally exploited. The Arabic system of classification, without knowledge of provenance identifies over eleven saker "types". Some of these are more favoured than others by Arab falconers and are therefore they are in greater demand from the wild. Assessment of morphological variation of birds chosen for known natal origin, showed that most variation was between-individuals-within-regions. However the remaining variation in size and plumage characters may be described as a weak cline between small dorsally uniform brown sakers from western lowland regions to large, dorsally barred russet, dark brown and grey coloured sakers from eastern highlands. Between these extremes exists a plethora of highly variable and contiguous populations and preferred falconry types may originate from any of these populations. However, there is evidence that sakers from north eastern Altai, Tuva, and Sayan populations, and the large sakers from eastern populations are overexploited.



12.00 - 12.15
FRANCO, ALDINA M. A. , Jorge M. Palmeirim and William J. Sutherland. Centre for Ecology and Evolution, University of East Anglia, Norwich NR4 7TJ, UK, <a.franco@uea.ac.uk> (AMAF), Centro de Biologia Ambiental, Fac. Ciências de Lisboa, Campo Grande, 1700 Lisboa, Portugal (JMP) and Centre for Ecology and Evolution, University of East Anglia, Norwich NR4 7TJ, UK (WJS).

THE ROLE OF TRADITIONAL AGRICULTURAL SYSTEMS FOR LESSER KESTREL CONSERVATION

The Lesser Kestrel, Falco naumanni, is one of the most threatened species in Europe due to its strong decline in recent decades and is classified according to Birdlife International as a Species of European Conservation Concern - SPEC1. Transects and radio telemetry showed that individuals have to travel further distances to find food in colonies surrounded by afforestation and that their home range is significantly larger than in colonies located in traditional agriculture systems. Foraging data shows that fallows are preferred, forests and areas near to villages are avoided and presence of cattle and roads are also positively selected by the species. In Portugal the EU agricultural policies are the main force causing land use changes due to large incentives for forestry and irrigation projects. These changes are occurring even within areas designated, under the Birds Directive, as Special Protection Areas for steppe birds conservation. In areas where maintenance of extensive cereal fields and rotation is crucial for the conservation of endangered steppe bird species, agri-environmental schemes should be strongly promoted in order to become more attractive for farmers than all other schemes.