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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 Landscape Ecology
Session Three

Thursday 18th July, 10.15 - 12.15, Grimond Lecture Theatre 2

Chair: Philip James




(BLOCK CAPITALS indicate the presenting author)

10.15 - 10.30
MANNING, ADRIAN, David Lindenmayer, Henry Nix and Simon Barry. Centre for Resource and Environmental Studies, Australian National University, Canberra, 0200, Australia, <adrianm@cres.anu.edu.au> (AM, DL and HN), Bureau of Rural Sciences, National Resource Information Centre, P.O. Box E11, Kingston, ACT, 2604, Australia (SB).

A MULTI-SCALE STUDY OF THE SUPERB PARROT IN SOUTHEASTERN AUSTRALIA

The objective of this presentation is to describe a multi-scale approach to research the Superb Parrot, Polytelis swainsonii; a vulnerable parrot endemic to southeast Australia. One of the greatest challenges facing humanity in the future will be the integration of conservation and production in the same landscape. The Superb Parrot is an ideal subject for investigating this issue because it lives almost exclusively on privately-owned agricultural land. It is part migratory and its distribution is influenced by factors over a wide range of spatial scales. Results of ecological studies have been shown to be dependant on the scale at which an organism is investigated. A multi-scale approach was therefore considered essential to research the Superb Parrot. Three scales have been used: Macroscale in which biogeographical factors are being investigated, with GIS databases, in relation to Superb Parrot occurrence across the whole landscape. Mesoscale local-landscape and intra-regional relationships are being investigated across a field study area of approx. 18,000 km 2 (81, 1km2 sites, randomly selected). Sites were surveyed for Superb Parrot. Microscale activity patterns and nest tree use are being investigated. The multi-scale approach will be discussed in the Australian context and its implementation in the field will be outlined.

10.30 - 10.45
VILELLA, FRANCISCO J. USGS-Biological Resources Division, Cooperative Fish and Wildlife Research Unit, Department of Wildlife and Fisheries, Mississippi State University, Mississippi State, MS 39762, USA, <fvilella@cfr.msstate.edu>.

USE OF NATIVE FOREST AND EUCALYPTUS PLANTATIONS BY ELEUTHERODACTYLUS FROGS

The use of tropical timber plantations by wildlife, particularly amphibians, is poorly known. We examined population dynamics and habitat use of Eleutherodactylus coqui in two montane forest reserves of Puerto Rico. We established grids of bamboo retreat sites on stands of native forest and eucalyptus plantations in each reserve. We used mark-recapture for population estimation during the wet and dry seasons. We used program CAPTURE to estimate frog populations and maximum distances moved. Densities of adult E. coqui were similar in three of four study grids. No differences in adult frog density were found among study sites during the wet season. Mean distances were found to differ between forests, with adult frogs in Maricao moving on average 60% farther than frogs in Guilarte. Habitat parameters differed among study sites. All four sites differed with respect to total epiphyte load. Five habitat variables were correlated with density of E. coqui. Eucalyptus plantations in montane regions of Puerto Rico provide suitable habitat for E. coqui. However, habitat suitability may be linked to threshold basal area levels. Silviculture practices (i.e., thinning) or natural periodic disturbances (i.e., hurricanes) may be required to maintain eucalyptus stands within appropriate basal area conditions for Eleutherodactylus species.



10.45 - 11.00
JAMES, PHILIP and North Mandy. TIES, School of Environment and Life Sciences, University of Salford, Allerton Building, Frederick Rd, Salford, Gt Manchester, M6 6PU, UK, <p.james@salford.ac.uk> (PJ), Environmental Planning, Cheshire County Council, Backford Hall, Backford, Chester, CH1 6PZ, UK (MN).

ECOLOGICAL FRAMEWORKS: THE CHESHIRE EXAMPLE

Nature conservation in the UK has historically focussed on site based activities. However, deterioration of the natural environment has not been prevented. Initiatives based on principles from Landscape Ecology and which involve the wider countryside are now being proposed. English Nature (Lifescapes) and the RSPB (Futurescapes) have presented national schemes. However, much conservation work is carried out at the county scale by a combination of the County Wildlife Trusts, Local Authorities and other local conservation organisations. This raises the question of how wider countryside issues can be addressed at the county scale? A critical evaluation of the Life ECOnet Project — based in Cheshire — is used to examine this question. Based on an action research methodology the Cheshire case study reviews the aims of the Project, discusses the Project’s work to date and sets out a critical evaluation of its impact. The role of an ecological framework is discussed in the context of conservation at the county scale. Analysis of outputs from the case study Project indicates that the Project has been influential in informing regional policies, has successfully engaged with local stakeholders and has established an ecological framework for the county. This draft framework is presented, described and evaluated.



11.00 - 11.15
ORTWINE-BOES, COLLEEN and Janet Silbernagel. Department of Landscape Architecture, University of Wisconsin-Madison, Room 1 Agriculture Hall, Madison, WI 53706, USA (cortwineboes@students.wisc.edu).

CONSERVATION IMPLICATIONS OF NATIVE BUMBLEBEE FORAGING DYNAMICS IN CRANBERRY AGROECOSYSTEMS

Due to habitat destruction and pesticide use, bumblebee populations have declined drastically in many parts of Europe and Canada. Although such devastating losses have not yet been documented for bumblebee populations in the United States, preventative strategies should be explored to ensure the conservation of this crucial part of natural and agricultural ecosystems. Cultivated cranberry (Vaccinium macrocarpon Aiton) marshes comprise an agricultural system in which bumblebees are particularly valuable as the most effective pollinator of this native North American plant. The mosaic of cultivated cranberry marshes and natural bogs found in northern Wisconsin landscapes allows growers to enhance native pollinators through conservation and planting designs. To that end, our research explores not only the plants and plant communities used by bumblebees in the land surrounding cranberry marshes, but also the spatial relationship of these plants and plant communities to bumblebee foraging patterns. Methods include: bee walks, pollen analysis, and digital video analysis. Our initial results indicate that bumblebee populations around cranberry farms could be protected and enhanced by managing land for certain plants and plant communities. Our intent is to develop conservation designs for cranberry growers and to draw implications for bumblebee conservation in other types of north temperate landscapes.



11.15 - 11.30
MILLER, JULIE K., Craig R. Miller, J. Michael Scott, and A. Ross Kiester. USDA, Forest Service, Rocky Mountain Research Station, Missoula, MT 59802, USA, <julesmiller32@hotmail.com> (JKM), Department of Fish and Wildlife, University of Idaho, Moscow, Idaho 83844, USA (CRM, JMS), USDA Forest Service, PNW Research Station, Corvallis, OR 97331, USA (ARK)

SUBURBAN SPRAWL AND THE THREE-TOED CRAWL: DEMOGRAPHIC CHANGE IN A TURTLE POPULATION ADJACENT A DEVELOPED EDGE

Little evidence exists for demographic impacts to wildlife from landscape change. Modified landscapes, including roads, may appear to ectothermic turtles as suitable habitat for basking and traversing, yet they may function as ecological traps where mortality is high. Using a 35-year study of three-toed box turtles, Terrapene carolina triunguis, we show demographic changes in a population whose surrounding landscape was fragmented and altered. We asked, are survival and age-structure of turtles occupying edges adjacent a road/subdivision different from turtles occupying the interior and more hospitable edges? The Wilcoxon rank sum test indicated the persistence of turtles on the inhospitable edge was significantly lower than turtles in the interior (P=0.005). Using chi-square goodness of fit, we found that in 1965/1966 (before landscape change) age-class structure along the inhospitable edge did not differ from that expected based on the whole population, however, by 1998/1999 (after change) age-class structure differed significantly. In contrast, there were no significant differences for the hospitable edges. Data gathered at an additional site in 2000 were consistent. Through the use of both temporal and spatial data, we provide evidence for the development of a population sink. Due to delayed maturity and low yearly reproductive output, these long-lived organisms are particularly vulnerable to chronic mortality.



11.30 - 11.45
BOLGER, DOUGLAS T., and Michael A. Patten. Environmental Studies Program, HB6182, Dartmouth College, Hanover, NH 03755, USA, <dbolger@dartmouth.edu>.

EFFECTS OF URBAN HABITAT FRAGMENTATION ON THREE TROPHIC LEVELS

We examined the effect of habitat fragmentation on four bird species, and their potential nest predators, and arthropod prey. Four landscape treatments were considered: interior and edge of large habitat blocks, large fragments (>75ha) and small fragments (<30ha). Different classes of nest predators responded differently to this fragmentation gradient. Snakes were much less abundant in fragments, particularly small fragments, than in edge and interior. Avian predators were most common in large and small fragments and lower in edge and interior. Nest predation rates on ground nesters closely paralleled the pattern of snake abundance. Depredation rates on Rufous-crowned sparrow (Aimophila ruficeps and Spotted towhee (Pipilo maculatus) nests were highest in interior plots and lowest in small fragments. Patterns in shrub nesters were less clear. The shrub-nesting Wrentit (Chamaea fasciata) exhibited little variation in predation rate across site types. Nest failure rate in the California towhee (Pipilo crissalis) peaked in edge and large fragment plots. The volume of potential arthropod prey was higher in edge and interior plots than in fragments. Correspondingly, clutch sizes were lower in fragments in three of four species. These results illustrate that responses to fragmentation are species specific and depend critically on reproductive and foraging ecology.



11.45 - 12.00
HOSTETLER, MARK, and Kim Knowles-Yanez. Department of Wildlife Ecology & Conservation, University of Florida, PO Box 110430, Gainesville, FL 32611-0430, USA, <hostetlerm@wec.ufl.edu> (MH), Liberal Studies Department, California State University San Marcos, San Marcos, CA 92096-000, USA, (KKY).

LAND USE, SCALE, AND BIRD DISTRIBUTIONS IN THE PHOENIX METROPOLITAN AREA

Most metropolitan areas have land use maps, but these maps have not been used to explore whether land use categories affect bird distributions. Further, most studies do not incorporate cross-scale analyses. We explored how land use, at ten different scales, affected the distribution of bird species surveyed in the Phoenix metropolitan area (Arizona) during the breeding season. We randomly selected 30 one-km transects, each divided into five 200-meter segments, and conducted bird surveys three times per month during the summer (May to July, 1998). We measured the amount of different land uses surrounding each segment from a small circular buffer, 100-m radius, to a large circular buffer, 2500-m radius. For each buffer area and species, we conducted multiple regressions between average bird counts and percent area represented by each land use category. Across all scales, only four of 26 species had significant regression results. Thus, land use has limited predictability on the number of birds found in an area of Phoenix. We hypothesise that land cover (i.e., structural design of an area), instead of land use, plays a primary role in affecting the distribution of most bird species in this urban environment.



12.00 - 12.15
Discussion