New Perspectives and Emerging Directions in Predator–Prey Functional Response Research: Hommage to C.S. Holling (1930–2019)

Nearly 60 years have passed since C. S. “Buzz” Holling (1930-2019) published his landmark papers describing the relationship between prey density and the predator’s per capita kill rate (i.e., ‘functional response’). Holling proposed several forms of the functional response, and provided mechanistic models for these relationships that were grounded in empirical support. Building these relationships into predator-prey models, which had previously assumed a linear functional response, radically changed their predictions and potential outcomes to prey populations in ways that continue to yield new insights. Holling’s initial work spurred decades of basic and applied research into functional responses across a range of predator and prey species, study systems, and ecological constraints. The functional response provides an explicit connection between behavioral and population ecology and has now been cemented as a key integrating concept in ecology, conservation biology, wildlife management, and biological control. Today, increasingly complex functional response models continue to be developed, novel data are collected to parameterize these models (e.g., through the advent of bio-logging and continuous-time animal monitoring techniques), and the analytical methods used to fit or parameterize functional response models have become increasingly sophisticated. More than half a century after Holling’s initial contributions, functional response research remains a fruitful and exciting area of investigation. This Research Topic will serve as a synthesis of where we currently are and where we need to go, for another half century of valuable functional response research.

This Research Topic will explore new perspectives and emerging directions in functional response research, reflect on underappreciated or poorly understood mechanisms, review best practices in model fitting and study design, and highlight challenges faced by contemporary ecologists as they seek to balance model parsimony with attempts to preserve ecological realism. A broader goal of this Research Topic is to promote dialogue and sustained interest among field biologists, mathematical theoreticians and laboratory empiricists who share an ongoing curiosity about this important area of investigation. The Research Topic will assemble contributions from leading experts and early career researchers who are active in the areas of population ecology, theoretical ecology, behavioral ecology, conservation biology, and ecological statistics.

We encourage submissions on the topic of the ‘functional response’ that address any of the themes identified above. We are seeking a mixture of empirical papers, review articles, and perspective pieces. Similarly, we are looking for contributions from theoreticians, laboratory empiricists, and field biologists. Review articles may seek to cover analytical approaches, study design considerations, or thematic topics (e.g., multi-prey functional response models, interference mechanisms, functional responses in host-parasite or plant-herbivore systems). Perspective pieces that highlight underappreciated or poorly understood mechanisms, and / or articulate future directions for functional response research are encouraged. Articles simply characterizing the functional response shape for a given predator-prey system will be given lower priority unless they explicitly: 1) reflect on underappreciated or poorly understood mechanisms, or 2) illustrate key principles associated with best practices in model fitting, study design, or interpretation. To the fullest extent possible, articles should touch on broader implications of the work, such as population-level implications of functional responses or the importance of functional responses in biological control or conservation biology. Inquiries about topic suitability can be directed to Thomas Hossie (thossie@trentu.ca) and Dennis Murray (dennismurray@trentu.ca).