Pathogens trigger top-down climate forcing on ecosystem dynamics

Abstract

; Vollestad, L. Asbjorn; Stenseth, Nils C.; Ghil, Michael. 2016. Pathogens trigger top-down climate forcing on ecosystem dynamics. Oecologia, 181 (2). 519-532. 10.1007/s00442-016-3575-8 Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. Pathogens trigger top-down climate forcing on ecosystem dynamics AbstractEvaluating the effects of climate variation on ecosystems is of paramount importance for our ability to forecast and mitigate the consequences of global change. However, the ways in which complex food webs respond to climate variations remain poorly understood. Here, we use long-term time series to investigate the effects of temperature variation on the intraguild-predation (IGP) system of Windermere (UK), a lake where pike (Esox lucius, top predator) feed on small-sized perch (Perca fluviatilis) but compete with large-sized perch for the same food sources. Spectral analyses of time series reveal that pike recruitment dynamics are temperature-controlled. In 1976, expansion of a perch pathogen into the lake severely impacted large perch and favoured pike as the IGP-dominant species. This pathogeninduced regime shift to a pike-dominated IGP apparently triggered a temperature-controlled trophic cascade passing through pike down to dissolved nutrients. In simple food chains, warming is predicted to strengthen top-down control by accelerating metabolic rates in ectothermic consumers, while pathogens of top consumers are predicted to dampen this top-down control. In contrast, the local IGP structure in Windermere made warming and pathogens synergistic in their top-down effects on ecosystem functioning. More generally, our results point to top predators as major mediators of community response to global change, and show that size-selective agents (e.g., pathogens, fishers or hunters) may change the topological architecture of food-webs and alter whole-ecosystem sensitivity to climate variation.

Fish conservation in freshwater and marine realms: status, threats and management

“…Climatic shifts are of growing concern, not least because the consequences of complex synergies with intensified threats may produce unexpected outcomes and ‘no analogue’ or ‘novel’ systems (Strayer, ; Acreman et al, ). For example, Edeline et al () have shown that a recent water temperature increase has had a significant impact on fish predator–prey interactions within a large temperate lake. Deciding how best to maintain or restore aquatic systems subjected to multiple stressors, including climate change, will challenge managers and planners, as discussed below.…”

Coupled Biospheric Synchrony of the Coastal Temperate Ecosystem in Northern Patagonia: A Remote Sensing Analysis

“…The seasonal variation of environmental drivers imposes its rhythms and thus phenological synchrony, where spatio-temporal fluctuations of different ecological patterns are locked in phase across different ecosystems [6][7][8]. A substantial body of literature documents that different populations are influenced by coherent environmental fluctuations (e.g., [2,3,[9][10][11][12][13][14]). For example, evaluating the effects of climate variation on the intraguild-predation structure of the fish population in the Windermere lake, Edeline et al [12] show that the pathogen-induced regime shift is temperature-controlled.…”

International Perspectives on the Effects of Climate Change on Inland Fisheries

“…Climate change also has had wider impacts on the Windermere ecosystem. Expansion of a pathogen of European Perch into the lake has acted synergistically with warming to induce a regime shift within its European Perch-Northern Pike interaction, triggering a trophic cascade (Edeline et al 2016). Trophic levels have responded differently to warming such that Windermere's phytoplankton, zooplankton, and timing of European Perch spawning have become desynchronized (Thackeray et al 2013).…”