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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 Alien and Invasive Species
Session Two

Thursday 18th July, 13.30 - 15.00, Grimond Lecture Theatre 1

Chair: Lynn Maguire




(BLOCK CAPITALS indicate the presenting author)


13.30 - 13.45
FULLER, ROBERT and Robin Gill. British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK, <rob.fuller@bto.org> (RF), Forest Research, Alice Holt Lodge, Wrecclesham, Surrey, GU10 4LH, UK (RG).

INCREASING NUMBERS OF DEER: A MAJOR FORCE FOR ECOLOGICAL CHANGE IN ENGLISH WOODS

Densities of several species of deer are increasing strongly in many areas of lowland England. This has widely caused severe impacts on woodland regeneration and vegetation structure. It has created particularly serious difficulties for maintaining traditional coppice management systems which are of high value for nature conservation. Using data from a variety of sources we show how browsing pressure has complex effects on vegetation structure by altering stem densities, tree height, canopy closure and foliage profiles. Data are presented to illustrate these changes in coppiced woodland. We review the implications for plant and animal communities. It is concluded that the scale of habitat changes now occurring in many lowland English woods as a result of intensified browsing pressure will have long-term ecological effects and is likely to lead to a reduction in the conservation value of many sites unless checked.

13.45 - 14.00
SUZAN, GERARDO, Jorge Salazar Bravo, and Terry Yates. Museum of Southwestern Biology. Department of Biology, University of New Mexico Albuquerque, New Mexico. 87131-0001, USA, <gsuzan@unm.edu>.

HUMAN-INDUCED HABITAT FRAGMENTATION FAVORS THE DISTRIBUTION OF HANTAVIRUS IN PANAMA.

Theories linking habitat fragmentation and diversity loss may also be useful at explaining the increase of disease outbreak risk. Our goal is to determine if a recent outbreak of hantavirus disease in Panama was linked to habitat fragmentation. To test this hypothesis we compared the small mammal species richness and distribution in six major Panama national parks with varying degrees of human intervention and size. In all areas, three areas of distinct habitat quality (well-preserved, edge, and disturbed habitats) were sampled in the summer of 2001. We collected representatives of four families, 14 genera and 18 species. However, this diversity was clearly apportioned between and amongst habitat categories. For example, 11 species were found exclusively in forested areas, 13 species in the edge sites, and eight species in the perturbed areas. In all cases, the rodent reservoir for Choclo virus (ethiological agent of hantavirus disease in Panama) was collected in perturbed or edge areas. We conclude that the change in the natural environment resulting from human activity (e.g., deforestation) may have favoured the distribution of hantavirus host, and possible, the recent outbreak. In addition, this study presents another example of the direct correlation between human disease risk and habitat fragmentation.



14.00 - 14.15
ALVAREZ-ROMERO, JORGE G. and Rodrigo A. Medellín. Laboratorio de Ecología y Conservación de Vertebrados, Instituto de Ecología, UNAM, Ciudad Universitaria, A.P. 70-275, México DF, Mexico, <jalvarez@miranda.ecologia.unam.mx>.

INTRODUCED MAMMALS OF MEXICO: DIVERSITY, DISTRIBUTION, POTENTIAL IMPACT, AND PRIORITISATION FOR THEIR CONTROL

Introduction of exotic species has been identified as a major problem for the conservation of biodiversity in Mexico, particularly for insular ecosystems. We made an extensive bibliographic search, complemented with personal communications, and the analysis of electronic databases to determine the distribution and potential impact of introduced mammals in Mexico. We also designed a method to classify them according to their potential impact on the native species and the feasibility to control or eradicate them. Mexico has at least 60 species of exotic mammals, 57 of these are from other parts of the world, while three are native, but translocated within the Mexican territory. Most of these species are under human control, but at least 16 have feral or free-living populations, and five were identified as commensals. Exotic mammals occupy many types of vegetation, but most were introduced to arid and semi-arid environments. Following the application of our classification method, we divide the species in four priority levels for their control.


14.15 - 14.30
PHILLIPS, R. BRAND, Howard L. Snell, Victor Carrión, and Joaquin Hernandez. Charles Darwin Research Station, Puerto Ayora, Galápagos Islands, Ecuador, <rbrand@fcdarwin.org.ec> (RBP, HLS, JH), Galápagos National Park Service, Puerto Ayora, Galápagos Islands, Ecuador (VC).

ALIEN SPECIES ERADICATION IN SOCIALLY SENSITIVE REGIONS: THE ROCK DOVE IN THE GALÁPAGOS AS A CASE STUDY

Alien species are now recognised as the most serious threat to biodiversity in the Galápagos Islands, with the risk of invasion increasing due to a rapidly growing human population. The expanding population, combined with an unstable economy, have in recent decades contributed to an increasingly volatile social environment. Implementing conservation programs under these conditions requires special considerations. In 2000, the Charles Darwin Research Station and Galápagos National Park implemented a four-year project to eradicate rock doves, Columba livia, from the archipelago. Our multi-faceted project incorporates a dove monitoring program, eradication efforts, information and education components, and collaborative agreements between the international, national, and local institutions. Here we describe the historical, social, and economic context of doves in the Galápagos. Midway through the project term, locating and removing doves has proven effective. In three months, using air rifles, baiting, and owner compensation, we removed 98% of the population from one of the three islands where they occur. We will discuss public relations methods and results, problems encountered, "lessons learned," and our continued efforts to achieve eradication on the remaining two islands. We will also discuss the potential to use this project as a model for future socially sensitive eradication projects.



14.30 - 14.45
PARKES, JOHN, David Choquenot and David Forsyth. Landcare Research, P.O. Box 69, Lincoln 8152, New Zealand, <Parkesj@landcare.cri.nz> (JP, DF), Department of Natural Resources and Environment, P.O. Box 500, E. Melbourne 3002, Victoria, Australia (DC).

ADAPTIVE EXPERIMENTAL MANAGEMENT (AEM) TO OPTIMISE THE CONTROL OF THE BRUSHTAIL POSSUM IN NEW ZEALAND.

Possums, Trichosurus vulpecula, are controlled over about one million ha of conservation areas in New Zealand at an annual cost of US$3.5 million. There is a trade-off between the area under control and the frequency and intensity of the maintenance control imposed. Some managers prefer a ‘press’ strategy with frequent control, while others prefer a ‘pulse’ strategy with control applied every few years. Some trigger their maintenance control on a set schedule, while others monitor either possum densities or conservation resource conditions and act when these reach a defined threshold. We report on the process taken to design a large-scale AEM to explore the costs (monitoring and control costs) and benefits (reduced possum impacts on forest canopies and area treated) resulting from different control frequencies. Secondly, we use the models developed as part of the AEM process to explore net benefits (average canopy conditions x area treated) of different control frequencies under a range of management scenarios (e.g., different budgets, areas to be treated, and control methods). The results allow managers to consider the trade-offs they must make between maximising local benefits versus optimal national benefits of possum control, with wider implications for all pest control undertaken with limited budgets.



14.45 - 15.00
MAGUIRE, LYNN A. Nicholas School of the Environment and Earth Sciences, Box 90328, Duke University, Durham, NC 27708-0328, USA, <lmaguire@duke.edu>.

CONSERVATION AND INVASIVE SPECIES: CAN DECISION ANALYSIS HELP?

Invasive species affect conservation goals directly, when invasive species alter native ecosystems through competition and predation, and indirectly, when actions taken to control invasive species threaten native species as well. Decisions about management of invasive species require complex prediction of direct and indirect impacts on conservation and delicate balancing between invasive species and conservation goals. The social concerns raised by these decisions range from economic damage to crops to aesthetic values of some invasives. I apply multiattribute utility analysis to management of feral pigs in Hawaii to show how: 1) Bayesian belief networks model the probabilistic relationships among feral pigs and native ecosystems, with parameters drawn both from available data and from expert opinion; 2) Objectives hierarchies articulate the goals and priorities of those most concerned with having plenty of pigs to hunt, those most concerned with limiting damage to native ecosystems, and those caught in the middle of the dispute, 3) The combined framework can facilitate communication among disputing parties in order to pave the way for a negotiated plan for management.