Trait-mediated processes and per capita contributions to ecosystem functioning depend on conspecific density and climate conditions

Abstract

The ecological consequences of environmental change are highly dependent on the functional contributions of the surviving community, but categorical descriptors commonly used to project ecosystem futures fail to capture context dependent response variability. Here, we show that intraspecific variability for a range of sediment-dwelling marine invertebrates is moderated by changes in the density of conspecifics and/or climatic conditions. Although these trait-mediated changes result in modifications to ecosystem properties, we find that the contributions of individuals to functioning are not necessarily additive but, instead, are a result of alterations to per capita performance. Our findings also indicate that trait variation within species can exert a greater influence on functioning than that of trait variation between species. Hence, projections of likely functional outcomes that scale from mean trait values are unlikely to be robust, highlighting a need to account for how and when intraspecific variability results in context-dependent community responses to change.

Combining three-dimensional acoustic coring and a convolutional neural network to quantify species contributions to benthic ecosystems

“…Our expectation is that prediction accuracy may decrease if multiple species or large shifts in density occur in a natural assemblage, but we anticipate that predictive capacity will improve to acceptable levels with further training of the machine learning algorithms. This raises the prospect of being able to use deep learning algorithms to non-invasively quantify the functional contribution of individuals and species within an intact community as they respond to changing circumstances [ 49 ] or predict future ecological consequences of altered biodiversity within the context of a dynamic system [ 44 ].…”

Ocean warming and acidification adjust inter- and intra-specific variability in the functional trait expression of polar invertebrates

“…We anticipated that changes in species behaviour will be more pronounced in regions of fast paced climate change 3 , 55 , as genetic and other coping mechanisms are less likely to be enacted in time. We speculated, given the closure of dispersal and adaptation as viable options, that adjustments to individual behaviour would dominate species responses to change 56 at higher latitudes. Here, using sediment-dwelling invertebrate species obtained from the Arctic Barents Sea (the bivalve Astarte crenata, sea star Ctenodiscus crispatus and polychaete Cistenides hyperborea ) and Antarctic Peninsula (the protobranch Aequiyoldia eightsi and bivalve Laternula elliptica ), two areas currently experiencing amplified climate change 57 , 58 , we explore the combined effects of near-term ocean warming (+ 1.5 °C) and elevated levels of atmospheric carbon dioxide (550 ppm [CO 2 ]) on aspects of species behaviour known to influence biogeochemical cycling.…”