4 resultados para Cryptic Prey

em Digital Archives@Colby


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Predator-prey relationships are an important aspect of the natural world, and, because of its relevance to survival and natural selection, is an interesting relationship to study. In amphibian larvae, level of activity and landscape use are often what determines the survival as prey. I studied the anti-predator behavior of the North American bullfrog (Rana catesbeiana) tadpoles when presented with dragonfly (Aeshna) larvae, a known predator of tadpoles. Tadpoles were acclimated to four different habitats with varying degrees of habitat cover, and were transferred to a new habitat with a degree of cover equal to one of the acclimation tanks. A restrained predator, and thus its chemical cue, was introduced, and the behavior, particularly the use of the habitat cover to hide from the perceived risk of predation was observed. A significantly higher frequency of inactivity was found in tank I than in II and III, and inactivity followed a general trend of decreasing with increasing habitat cover. Difference in tank cover was not found to have a significant effect on swimming behavior, but did have a significant effect on hiding behavior, which increased with higher availability. Foraging decreased significantly with the addition of a predator, but did not vary significantly with different levels of cover. Hiding behavior and reducing conspicuous behaviors (like foraging) are probably the behaviors that afford the tadpole the most success at eluding a predator in their natural environment.

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Large-carnivores and humans are increasingly in conflict as humans encroach on their natural territory. As a result, many large-carnivore species have become endangered due to habitat destruction, prey reduction and retaliatory killings from conflicts. No global internet database, however, exists to document, monitor and evaluate these conflicts, particularly to take advantage of the growing spatial resources available. Using human-tiger conflicts in Malaysia and Sumatra as a case study, this project explores how such a database could be created. GIS was used to conduct multiple analyses on the data obtained about these conflicts. We conclude that a database would require data to be compiled according to a protocol based on these spatial scales: Point, Sub-State Polygon and Provincial.

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After declining steadily for several decades, the South China tiger (Panthera tigris amoyensis) is now thought to be extinct in the wild. However, there is some hope of reintroduction, with Hupingshan-Houhe and Mangshan-Nanling National Nature Reserves in southern China seeming to hold the most promise. Our study used slope, elevation, vegetation, and landcover variables to construct a rough habitat suitability index for tigers in these two parks. According to our model, there are areas of suitable habitat within both parks. However, there are some important variables that we were unable to include in our model, such as human population density and prey availability. Considerable in-depth research will be necessary to evaluate the suitability of these locations before reintroduction is considered.

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The eastern timber wolf (Canis lupus lycaon) once inhabited Maine, as well as the rest of the eastern United States and southern Canada. As a result of human land use and widespread extermination campaigns, wolf numbers dramatically decreased, and by the early twentieth century, no wolves remained in Maine. As large carnivorous and territorial mammals, wolves require contiguous undeveloped areas with abundant prey. This project is a feasibility study that identifies the areas in Maine that are suitable for the reintroduction of wolves. We used GIS modeling to identify contiguous forested areas over 1,000 km2, calculate road and population density, and map the presence or absence of prey throughout the state. These variables were combined in a habitat suitability model to determine the location and amount of suitable wolf habitat in Maine. The northwestern part of the state appears most suitable for wolf reintroduction as it is relatively undeveloped with low road and population densities. There is also a smaller isolated area in Washington County that might be suitable, but further investigation is required.