Suchergebnisse

Understanding what factors infl uence species occupancy in human-modifi ed landscapes is a central theme in ecology. We examined scale-dependent habitat relationships and site occupancy in reptiles across three topographically diff erent study areas in south-eastern Australia. We collected presence – absence data on reptiles from 443 sites associated with three longterm biodiversity monitoring programs, on four to seven occasions, between 2001 and 2013. We characterised sites by the following four variable domains: 1) fi eld design, 2) topography, 3) local-scale vegetation attributes and 4) landscapescale vegetation cover. We constructed occupancy models for 14 species and used an information-theoretic approach to compare multiple alternative hypotheses to explain occupancy within and between study areas. We modelled detection probability and used the model with the lowest AIC in subsequent analyses. We then modelled occupancy probability against all subsets of the variable groups (fi eld design, topography, local- and landscape-scale vegetation), as well as a model that held occupancy constant (null model). We found that local-scale vegetation attributes were important for explaining site occupancy in 12/19 possible models, although, in several cases model fi t was improved by the addition of topographic variables or native vegetation cover in the surrounding landscape. Occupancy models for widespread species were broadly congruent across study areas. We demonstrate that topographic variables are important for explaining reptile occupancy in hilly landscapes, and local- and landscape-scale variables are important for explaining reptile occupancy in fl at or gently undulating landscapes. Management actions that improve habitat complexity at a site-level, and encompass entire topographic gradients, will have greater benefi t to woodland reptiles than simply increasing vegetation cover in the surrounding landscape. ; This study was funded by the Australian Government's Caring for our Country scheme, the Murray Local Land Services and the Australian Research Council.

Context
Artificial refuges (cover boards) are a popular method to survey and monitor herpetofauna worldwide. However, one limitation of using artificial refuges in terrestrial environments is the low detection rates of arboreal species. Furthermore, destructive search techniques can damage critical microhabitat such as exfoliating rock or flaking bark of mature trees.

Aim
We tested a non-destructive, passive method of sampling arboreal reptiles in fragmented agricultural landscapes in south-eastern Australia.

Methods
We installed 84 artificial bark refuges consisting of strips of non-toxic, closed-cell foam attached to eucalypt trees in 13 patches of remnant vegetation. We used Bayesian statistics to compare differences in detection rates among artificial bark refuges, terrestrial artificial refuges and active searches of natural habitat over a 4-year period.

Key results
Active searches combined with terrestrial artificial refuges detected the highest number of reptile species, including several cryptic fossorial species. Artificial bark refuges detected, on average, 132 times more individuals of the arboreal southern marbled gecko, Christinus marmoratus, than did terrestrial refuges. Gecko abundance patterns were related to tree characteristics such as tree size, bark thickness and stand basal area, as well as survey year.

Conclusions
Traditional survey methods such as terrestrial cover boards, in combination with active searches of natural habitat, may significantly underestimate counts for arboreal gecko species.

Implications
Artificial bark refuges provide a cost-effective, non-destructive and durable method for surveying and monitoring arboreal reptiles in woodland environments over short to medium time frames. Foil-backed, closed-cell foam has broad application for use in spatial capture–recapture studies and long-term monitoring of arboreal reptiles. This method also may be effective for procuring records of threatened arboreal geckos or as a solution for providing temporary habitat in ecological restoration projects.

A large-scale biodiversity monitoring program examining the response of herpetofauna to the Australian Government's Environmental Stewardship Program is taking place in south-eastern Australia within the critically endangered Box Gum Grassy Woodland veget

A large-scale biodiversity monitoring program examining the response of herpetofauna to the Australian Government's Environmental Stewardship Program is taking place in south-eastern Australia within the critically endangered Box Gum Grassy Woodland veget

A large-scale biodiversity monitoring program examining the response of herpetofauna to the Australian Government's Environmental Stewardship Program is taking place in south-eastern Australia within the critically endangered Box Gum Grassy Woodland vegetation community. Field surveys involve counting reptiles in areas under Environmental Stewardship management. These "Stewardship" areas have been matched with areas managed for primary production (domestic livestock grazing). We list reptiles recorded during surveys conducted between 2010 and 2012. We recorded sixty-nine species from ten families. The list will be useful for workers interested in the zoogeographical distribution of reptiles and amphibians in fragmented agricultural woodland ecosystems.