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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
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timetable
(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.
The SCB2002 pages are maintained by Christine Eagle
email: C.M.Eagle@ukc.ac.uk
Conference email: scb2002@ukc.ac.uk
Last updated: 30.06.02