Trade-offs between short- and longer-term resilience to warming within and between subtidal marine assemblages

Abstract

Subtidal marine ectotherm physiological responses vary with ocean warming. Predicting these responses is important for ecosystem assessments to inform management and conservation strategies. Falkland Islands coastal species representing different mobility, feeding guilds, and habitats were tested, through laboratory incubation experiments, to estimate their short- (acute - seconds to hours) and longer-term (acclimation - weeks to months) resilience to ocean warming, to understand if ecological traits affect temporal trade-offs in responses, and contrasted with other marine assemblages. We found trait-specific, and species-specific, trade-offs in resilience to short-term and longer-term warming. Filter feeders and predators had higher acute tolerance than detritivores and herbivores. Lower acclimation capacity was found in molluscs, sessile species, filter feeders and kelp associated species. Benthic species had amongst the highest acclimation capacity. When compared to analogous experiments conducted with the same methodology at 10 different locations, across latitudes, we found a consistent relationship between short- and long- term resilience across marine assemblages, but with notable exceptions from unpredictable environments with episodic warming events; the Peruvian upwelling and Falklands fauna had a lower short-term resilience, relative to their longer-term resilience, than the other assemblages. When predicted rates of ocean warming under a high anthropogenic carbon emission scenario and anticipated increases in marine heat waves were taken into account, low latitude assemblages showed greater vulnerability in terms of years until acute thermal safety margins are breached (less than 500 years) than higher latitude assemblages (up to 4000 years), which is largely driven by projected rates of ocean warming. Understanding this variation, and the relationship to predictability, in coastal communities will be informative for predicting ecosystem responses and informing management and conservation strategies.

Keywords: Coastal assemblages; Ecological traits; Environmental predictability; Falkland Islands; Latitude; Marine ectotherms.

Fig. 1

Sample (red circles) and experimental facility (black circle) locations. Inset shows the Falkland Islands with the red rectangle indicating the sample area on the East Falkland coast.

Fig. 2

Relationship between rates of warming and CT_max for the Falklands faunal assemblage (a) by species (KBI = G. trapesina, KLI = N. mytilina, PUR = A. canaliculata, SLK = small G. gregaria, KIS = C. emarginata, LLK = large G. gregaria, SER = A. schythei, and WHE = P. plumbea), (b) by phyla, (c) by mobility, (d) by feeding guild (DETR = detritivore, FILT = filter feeder, HERB = herbivore, PRED = predator), (e) by habitat, and (f) by association with the kelp forest. Solid lines indicate significant relationships, while dotted lines indicate non-significant relationships.

Fig. 3

Slope and intercept values representing relationship between rates of warming and CT_max based on community assemblages from different locations, with 95% confidence intervals (grey shading). Data from locations other than the Falkland Islands are extracted from Morley et al. (2014) and Richard et al. (2012). FI = Falkland Islands; CT = cold temperate (Scotland); NHWTSW = < 2 m depth warm temperate (France, US); SHWT = warm temperate (Peru); NHWT = warm temperate (France, US); and NZ = New Zealand. The Falkland Islands is highlighted by the triangle shape and larger size.

Fig. 4

The number of years it will take before the CT_max of an assemblage is reached against their latitude. The different colours represent different locations. FI = Falkland Islands; CT = cold temperate (Scotland); SHWT = warm temperate (Peru); and NZ = New Zealand. The different shapes refer to whether the MHW elevation was applied in the estimate of the number of years until CT_max would be reached or not. The Falkland Islands is highlighted by the triangle shape and larger size.