Anthropogenic habitat change is the most important factor contributing to global losses in biodiversity. Ecological research can help identify the mechanisms that cause these declines by relating environmental characteristics to wildlife habitat use and productivity. Such studies can contribute to the design of land-use practices that enhance wildlife populations in conservation areas and promote efficient compromises between human use and conservation.
The conflicts between human-use and conservation are particularly evident in coastal areas, which have enormous economic value and are thus coveted areas for development. Human-use can alter the habitat quality and affect coastal taxa, such as shorebirds.
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In this study I examine the breeding ecology and conservation biology of a beach-nesting, near-threatened shorebird, the Malaysian plover Charadrius peronii, which breeds on coastal areas throughout Southeast Asia. Although nearly half of the threatened shorebird species breed in tropical areas, little research has been conducted on the conservation and ecology of these species. My study is the first detailed research conducted on the Malaysian plover. It contributes to a better understanding of the environmental factors constraining breeding strategies in the tropics and identifies key mechanisms linking anthropogenic habitat change and wildlife populations.
I used behavioural approaches to collect a wide range of data over a short-time period in order to describe the breeding ecology of Malaysian plovers, evaluate different types of constraints, identify anthropogenic impacts and provide recommendations on management approaches to mitigate the impacts of habitat change.
Malaysian plovers have long breeding seasons, high site fidelity, complete biparental care and can nest multiple times in a single year. In contrast to shorebirds in Arctic environments, where fecundity is limited by the brief pulses of high seasonal productivity, Malaysian plover fecundity appeared to be constrained more by habitat availability rather than time. Malaysian plovers began defending territories several months prior to the breeding seasons and nested in the same habitats even if there were significant reductions in habitat quality throughout the course of the breeding season.
In the Gulf of Thailand tourism-related habitat change that narrows beaches, alters vegetation structure and enhances human disturbance levels reduce habitat availability and breeding success. Enhanced vulnerability of clutches to tidal flooding, chicks to predation, exposure of eggs to heat and chicks to predation may be key mechanisms leading to these effects. Moreover Malaysian plovers had a density-dependent decline in breeding success. Consequently, if birds are displaced from preferred beaches due to habitat change, then breeding success may be reduced in otherwise high quality habitat as plovers crowd into remaining beaches.
When people approach nesting or chick-rearing plovers, one or both of the adults will leave the clutch or chicks to conduct distraction displays. Compared to holarctic species, tropical shorebirds may be more vulnerable to the fitness impacts of human disturbance because even short periods of exposure to direct sunlight can cause clutch failure, whereas eggs are resistant to chilling. These results suggest that the environmental and ecological conditions in tropical regions may affect the susceptibility of breeding shorebirds to fitness impacts of anthropogenic disturbance and habitat change.
Future research should assess cumulative impacts of habitat change by conducting multispecies studies and include wintering or stopover shorebirds. As my research was conducted in the best Malaysian plover breeding habitat in Thailand, it is important to assess the generality of my results by comparisons to other regions or across several years in which there may be a different range of predators or prey. Finally, it is important to note that these types of ecological conservation studies are only a first step towards
successful protection of threatened species. The greater challenge is to tackle the ultimate socio-economic and institutional factors that limit the effectiveness of protected areas and contribute to the number of environmentally destructive coastal development projects.
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/2349 |
| Date | 11 March 2010 |
| Creators | Yasue, Mai |
| Contributors | Dearden, Philip |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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