The distribution and abundance of animal populations in a climate of uncertainty

Abstract

Current predictions regarding the ecological consequences of climate change on animal populations are generally autecological and species‐specific, and/or non‐mechanistic extrapolations of recent short‐term patterns. To better understand and predict the effects of climate change on the distribution of species and the abundance of populations we offer a novel, broad theoretical framework. Climate‐induced changes in trophic structure may actually be more predictable than effects on individual species. The logic is that there are general differences in climatic sensitivity among trophic levels – specifically, that as one moves up trophic levels, there is an increase in the temperature sensitivity of vital rates. More precisely, we provide: (1) a formal mathematical definition of distribution limits that is both operational and conceptual, introducing the concept DL50, defined as the geographic and climatic isoline representing an equilibrium occupancy of half of the suitable habitats; (2) a matrix of the possible changes in trophic structure from climate change and the general theoretical consequences; and (3) a new idea that predicts broad effects of climatic warming on trophic systems. Our intention is to help meet the challenge of developing and testing general theoretical models that can predict which species will be winners and losers in ecological time, which evolutionary traits will be favoured or selected against, and what will be consequences for ecosystem structure and function.

Climate Change, Range Shifts and Multitrophic Interactions

“…Accordingly, there is critical springtime photoperiod, which is an important pre-requisite before floral development can begin [141,142]. Net photosynthesis (primary production) typically peaks within the range of normal temperatures [143,144], however increasing temperatures can shift this peak and extending the growing season and consequently accelerate plant growth [145]. This situation can lead to key differences with respect to interactions with insect mutualists or antagonists [16] and subsequently changes in the population dynamics can alter evolutionary trajectories [146], creating "evolutionary noise" with unpredictable consequences for the strength and persistence of trophic interactions.…”

Modelling natural disturbances in forest ecosystems: a review

“…Examples were presented by Wilder (1999), predicting the timing and magnitude of L. dispar outbreaks based on egg and larval performance, and Régnière and Bentz (2007), mechanistically modelling the regulation of population dynamics by density independent winter mortality and stage specific cold-tolerance. An important aspect in modelling population dynamics are the regulatory effects of predators and parasitoids (e.g., Mills and Getz, 1996;Abbott and Dwyer, 2007;Berggren et al, 2009). Modelling insect population dynamics is a particularly valuable approach in the context of pest control, where models were developed to simulate pheromone trap efficiency (Byers, 1993), bark beetle flight behaviour (Byers, 1996) and the risk of outbreaks based on pheromone trap records Stergulc, 2004, 2006).…”

Temperature affects insect outbreak risk through tritrophic interactions mediated by plant secondary compounds

“…As climate warms, it is likely that regulatory processes of populations will be affected. One reason for this is that the strength of interactions within and between trophic levels often depends on climatic conditions and that species at different trophic levels may respond differently to increasing temperature (Berggren et al 2009, Gilman et al 2010, Montoya and Raffaelli 2010. Insects are particularly sensitive to changes in temperature, and increasing temperatures due to global warming have in general been predicted to lead to improved performance and more generations per year (Bale et al 2002).…”