White-tailed deer population dynamics in a multipredator landscape shaped by humans

Area of Science:

• Ecology
• Wildlife Management
• Conservation Biology

Background:

• Large terrestrial mammals increasingly inhabit human-modified landscapes.
• Understanding predator-prey dynamics in these areas is crucial for effective wildlife management.
• White-tailed deer in northeastern Washington face predation from multiple carnivores, including wolves, in a human-altered environment.

Purpose of the Study:

• To investigate the factors influencing white-tailed deer population dynamics in a human-modified landscape.
• To assess the relative impacts of various predators and land management practices on deer survival and population growth.
• To understand the interplay of top-down (predation) and bottom-up (forage availability) factors.

Main Methods:

• Radio-collaring and monitoring of white-tailed deer, bobcats, cougars, coyotes, and wolves (2016-2021).
• Estimation of deer vital rates and population growth rate using a stage-structured matrix model.
• Application of Cox proportional hazard models to assess the influence of predator exposure, landscape use, and winter severity on deer survival.

Main Results:

• The white-tailed deer population was stable to declining (lambda=0.97).
• Apex predators, particularly cougars, negatively impacted deer population growth, while timber harvest and agricultural areas positively influenced it by increasing forage.
• Vehicle collisions represented a significant source of deer mortality, though proximity to roads did not affect overall population growth.

Conclusions:

• White-tailed deer populations in human-modified landscapes experience dual regulation by top-down (predation) and bottom-up (forage) factors.
• Reducing vehicle collisions could benefit both deer populations and human safety.
• Management strategies should consider the complex interactions between predators, habitat alteration, and prey dynamics.