Long‐term warming affects ecosystem functioning through species turnover and intraspecific trait variation

Abstract

Effects of climate change on natural ecosystems can be mediated by ecological processes, but also by rapid evolutionary adaptations and/or non‐heritable trait changes in organisms. So far, most studies testing the importance of inter‐ versus intraspecific changes for how communities and their functioning responds to climate change are either short‐term laboratory experiments in highly controlled (artificial) environments, or long‐term field surveys suffering from lack of experimental manipulation. Here, we quantified how community composition and functioning has changed in response to long‐term warming, including the potential direct and indirect effects via immediate and delayed physiological, non‐heritable plastic, ecological, evolutionary and eco‐evolutionary responses. We used a site‐for‐time approach, sampling sites in an artificially heated basin and a nearby area to quantify how >30 years of experimental warming in situ affects benthic grazer communities and traits of grazer taxa, as well as their contribution to a key ecosystem function: grazing on filamentous algae. The community composition shifted with warming, because a non‐native species was highly common, and taxa with higher mobility, became more common in the heated areas compared to the control sites. Warming altered community functioning but the underlying mechanisms varied between traits: increased metabolism was caused by intraspecific trait change, while increased grazing rate was mainly driven by species turnover. Our results suggest that both population‐ and community‐level processes mediate the responses of natural communities to long‐term environmental change, and that the ongoing warming of coastal waters is likely to alter the functioning of key marine ecosystems.

Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning

“…Overall, observations of past changes, experimental work and modelling studies suggest that climate change can cause complex responses in relation to other environmental factors (e.g. eutrophication) and influence carbon storage in both macroalgae and vascular plants in the Baltic Sea (Jonsson et al, 2018;Takolander et al, 2017a;Röhr et al, 2016;Salo et al, 2020;Bobsien et al, 2021).…”

Identifying biotic drivers of population dynamics in a benthic–pelagic community

“…Baltic Sea, benthic-pelagic coupling, density dependence, interactions, population dynamics, state-space model the sediment (Karlson et al, 2007;Norkko et al, 2012;Griffiths et al, 2017). When considering long-term effects of such extrinsic variables, both population-and community level processes are important to account for, as they together explain the functioning of the community (Salo et al, 2019). This calls for joint investigation of biotic interactions and extrinsic variables in forming and maintaining community dynamics (Walther, 2010 and references therein).…”

High taxonomic resolution surveys and trait-based analyses reveal multiple benthic regimes in North Sulawesi (Indonesia)

“…Ecosystems worldwide are experiencing profound ecological changes including biodiversity losses 1 and community rearrangements (i.e., non-random species turnover) 2 , which are expected to worsen with climate change, even under moderate CO 2 mitigation scenarios 3 . Non-random species turnover, which depends on the susceptibility of the organisms’ traits, can disrupt vital ecosystem processes such as trophic energy flow 4 or habitat provisioning 5 , deeply affecting ecosystem functioning and resilience 6 . Understanding distinct and emerging species configurations and their contribution to key ecosystem functions is therefore needed to establish effective conservation and management strategies 7 , 8 .…”