(c) Wade Paskett
Waterfowl Ecology & Management
At the heart of the Koons lab is a fondness for studying waterfowl ecology and management. Beginning with studies of lesser scaup, lab members have since studied numerous dabbling and diving ducks, sea ducks, and arctic geese. Attention is paid to the role population dynamics play in driving trophic interactions, community dynamics, and biodiversity. But we have not abandoned single-species studies that are valuable for guiding conservation and management. By basing our research on sound theory like that described below, we aim to conduct empirical research that leads to the best management solutions. Currently, we are trying to decouple the impacts of harvest management, habitat management, and climate change on waterfowl population dynamics at large spatial and temporal scales. To achieve these goals we are reconciling information contained in publicly available datasets with more detailed findings from smaller study sites using Bayesian "integrated population models" and other hierarchical models.
Population Dynamics and Species Interactions in Changing Environments
Both natural and anthropogenic changes to the environment cause changes in vital rates (growth, survival, reproductive success, and dispersal), which in turn give rise to changes in population structure (age, stage, size, or spatial structure of abundance). As part of an organism's environment, interactions with other species (e.g., predation, competition, etc.) can do the same. Rarely considered, changes in population structure can affect population dynamics in non-intuitive ways relative to a focus on the vital rates alone, such as causing a population to decline even when mean reproductive success output outweighs mean mortality. Perturbations to population structure may be transient in nature, but can induce lasting effects on abundance via the inertia (or momentum) of historical population structure (e.g., the baby boom generation). But when temporal variability in the environment leads to regular changes in vital rates, the resulting changes in population structure become a regular part of population dynamics in our ever-changing world. Our lab seeks to better understand the relative roles of various vital rates and population structure in driving the population and community dynamics of wild plant and animals with structured life cycles. By weaving theoretical studies with evaluations of empirical data, we aim to become better at forecasting the impacts of environmental change on population and community dynamics, in turn providing guidance to harvest management, invasive species management, predator-prey conservation, and sustainable conservation of biodiversity amidst the pressures of global change.
Individual Heterogeneity & Population Dynamics
In addition to environmental variation, we are also interested in studying the ecological and evolutionary processes that shape genetic and phenotypic variation among individuals in a population, collectively referred to as "individual heterogeneity". In particular, we are trying to better understand how population density, resource availability, and pathogen exposure early in life can affect physical and physiological development, early-life demographic performance, and how these processes shape late-life senescence. These sources of individual heterogeneity, and others, may play a significant role in compensation of human harvest and natural predation. Although often ignored, individual heterogeneity could thus have a significant impact on population dynamics through a myriad of demographic pathways. Long-term studies of marked individuals in the wild have clearly demonstrated that mean population performance is commonly driven by a few individuals with high Darwinian fitness whereas most never achieve any fitness at all. When designing conservation and management plans, this is a reminder that individual heterogeneity may be the key to achieving objectives rather than the exception.
Life History Evolution in an Uncertain World
In addition to contemporary studies of population and community dynamics in changing environments, the lab also examines the implications of environmental uncertainty for life history evolution. Temporal changes in the environment can change vital rates, population structure, and eventually lead to the evolution of life history strategies that differ from those that are optimal in constant environments (the latter of which is a common assumption in evolutionary studies). For example, life-cycle delays and allocation of resources away from reproduction toward survival and longevity all decrease short-term fitness, but these bet-hedging strategies can drastically improve long-term fitness in uncertain environments. While this "buffering" of vital-rate responses to environmental variability seems to be advantageous in long-lived species, short-lived species might adopt the opposite strategy of allowing their survival and reproductive success to change in a labile fashion as their environment changes; allowing them to take advantage of environmental booms that can outweigh busts when reaction norms are nonlinear. Collaborators and I use theoretical studies and long-term empirical data to better determine how life histories evolve in the real world that changes all the time. With a fundamental understanding of how wild plants and animals have evolved to cope with environmental change, we are better equipped to provide sound conservation and management strategies for preserving the many ecosystem services that wild plants and animals provide.
Mammal Ecology & Management
In more recent years, we've started studying mammalian population dynamics and species interactions across North America. Working with colleagues that specialize in mammal ecology or human dimensions, we use the same approaches as those described above to provide novel and efficient solutions to solving human-wildlife conflicts and to guide the management of both declining and overabundant species.