Landscape and population ecology of ring-necked pheasants

pheasants;population dynamics;suvival;chick survival;nest success;grasslands;CRP;predation

Lyons, Timothy Patrick

关键词: pheasants;    population dynamics;    suvival;    chick survival;    nest success;    grasslands;    CRP;    predation;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/99214/LYONS-DISSERTATION-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Species inhabiting intensively farmed landscapes are dependent on private and public lands managed for the benefit of wildlife. While the benefits of different management approaches at the field- and landscape scale are well-recognized, how to prioritize actions is less clear. Much of this difficulty arises from a lack of information about the mechanisms linking field- and landscape-scale management to population-level responses. I collected detailed demographic data on ring-necked pheasants on 14 public and private grasslands in east-central Illinois. I monitored 108 nests, 38 broods, and the survival and habitat use of 108 adult female ring-necked pheasants (Phasianus colchicus) throughout the year between May 2014 and August 2016.My goal was to better understand how field- and landscape-scale habitat features affected stage-specific demographic parameters and population growth in ring-necked pheasants. I found that field- and landscape-scale habitat features often had contrasting effects on chick survival, adult survival, and nest success. Increasing the proportion of grassland in the surrounding landscape improved nest success, but had a negative effect on chick survival. Similarly, the amount native grasses within fields had a positive effect on adult survival, but a negative effect on chick survival. Still, population growth was most sensitive to increases in native grass, but peaked at intermediate amounts of native grass cover. I also sought to identify the predators of pheasants and clarify how vegetation, field size, and landscape composition affect predation risk. I used automatic telemetry to determine the time of death and classify predators of male and female pheasants inhabiting 5 grassland fields. I classified the time of death for 70 pheasants and related field- and landscape-scale habitat conditions to predator identity for 32. My results showed that raptors were the most common predators of pheasants. Both raptors and mesopredators were more likely to prey on pheasants in large fields than small ones. Predation by raptors could be minimized by increasing the amount of native grasses within fields. Still, pheasant populations were growing during my study, suggesting that raptors were not limiting population growth. Overall, my research demonstrates the need for a mechanistic understanding of how field- and landscape conditions can affect the population demography of wildlife. By incorporating more detailed information about the relationship between habitat characteristics, predation patterns, and demography across multiple life-stages, wildlife managers can make more effective decisions.