Food Web Rewiring in a Changing World - Supplementary Information
Food web rewiring in a changing world - Figure 3
Figure 3. The aggregate rewiring of food webs through the unified behavioural responses of entire suites of species. (A) The aggregate behavioural response of coldwater fishes to move into deeper, offshore waters with climate warming, which suggests the rewiring of boreal shield lake food webs. (B) The residual average log10 depth of capture for 13 coldwater fish species increases across a gradient of increasing average recent air temperature based on spatial catch-per-unit-effort data from 721 lakes in Ontario, Canada, indicating that cold-water species were on average caught in deeper water in warmer lakes (adapted from Bartley109, see Supplementary Information). (C) The slope coefficient (with standard error) for regression models of the residual average log10 depth of capture across a spatial gradient of average recent air temperature for each of 13 cold-water species, showing many species contribute to the unified behavioural response of these species to increased temperature (adapted from Bartley109, see Supplementary Information).
Food web rewiring in a changing world - Figure 2
Figure 2. Three examples of food web rewiring with climate change from diverse ecosystems. (A) Rewiring of the arctic marine food web in Cumberland Sound, Nunavut, Canada. As capelin (Mallotus villosus) move northward into Arctic marine ecosystems, both beluga whales (Delphinapterus leucas) and Greenland halibut (Reinhardtius hippoglossoides) increase their foraging on forage fish. These responses change the summertime relationship between belugas and halibut from a primarily predator-prey interaction to a primarily competitive interaction (adapted from Yurkowski et al.62). (B) Rewiring of the food web across the Arctic land-sea interface. During periods of reduced sea ice, polar bears (Ursus maritimus) spend more time on land, spatially isolated from their preferred prey of ringed seals (Pusa hispida). While on land, the bears predate more on nesting seabirds and their eggs and less on ringed seals, altering the strengths of their interactions with these resources (adapted from Prop et al.63, Hamilton et al.64, and Smith et al.65). (C) Rewiring of the food webs of coastal Pacific North America. Kodiak brown bears (Ursus arctos middendorffi) feed on both terrestrial red elderberry (Sambucus racemosa) and on sockeye salmon (Oncorhynchus nerka). While these two resources were previously staggered in time, climate impacts pushed the elderberry to bloom earlier and now in synchrony with salmon, effectively forcing the decoupling of terrestrial and aquatic habitat that was mediated by bears (adapted from Deacy et al.68).
Food web rewiring in a changing world - Figure 1
Figure 1. The asymmetrical impacts of climate change create novel heterogeneity, from local to global spatial scales. (A) Global temperature data from 1880-2017 indicate temperatures in the Northern hemisphere are increasing more rapidly than in the Southern hemisphere (adapted from 116,117). (B) The ratio of land/sea warming rates from many climate change models shows that land is warming faster than seas (adapted from Sutton et al.24). (C) Because of thermal stratification in lakes, indicated by this vertical temperature profile, the nearshore (littoral) areas and surface waters of lakes are warming faster than deep and offshore (pelagic) areas. (D) Temperature increases vertically farther from the soil surface to the top of grasses in grassland ecosystems (adapted from Barton and Schmitz110).