Adaptive genetic variation mediates bottom-up and top-down control in an aquatic ecosystem

Abstract

Research in eco-evolutionary dynamics and community genetics has demonstrated that variation within a species can have strong impacts on associated communities and ecosystem processes. Yet, these studies have centred around individual focal species and at single trophic levels, ignoring the role of phenotypic variation in multiple taxa within an ecosystem. Given the ubiquitous nature of local adaptation, and thus intraspecific variation, we sought to understand how combinations of intraspecific variation in multiple species within an ecosystem impacts its ecology. Using two species that co-occur and demonstrate adaptation to their natal environments, black cottonwood (Populus trichocarpa) and three-spined stickleback (Gasterosteus aculeatus), we investigated the effects of intraspecific phenotypic variation on both top-down and bottom-up forces using a large-scale aquatic mesocosm experiment. Black cottonwood genotypes exhibit genetic variation in their productivity and consequently their leaf litter subsidies to the aquatic system, which mediates the strength of top-down effects from stickleback on prey abundances. Abundances of four common invertebrate prey species and available phosphorous, the most critically limiting nutrient in freshwater systems, are dictated by the interaction between genetic variation in cottonwood productivity and stickleback morphology. These interactive effects fit with ecological theory on the relationship between productivity and topdown control and are comparable in strength to the effects of predator addition. Our results illustrate that intraspecific variation, which can evolve rapidly, is an under-appreciated driver of community structure and ecosystem function, demonstrating that a multi-trophic perspective is essential to understanding the role of evolution in structuring ecological patterns.

Analysing eco‐evolutionary dynamics—The challenging complexity of the real world

“…Quite a few studies (e.g., Bassar et al, ; Farkas et al, ; Fridley & Grime, ; Pantel et al, ; terHorst et al, ; Walsh et al, ) used isolates or populations that evolved in a natural or multi‐species context. However, only three of the nonmicrobial studies (Faillace & Morin, ; Fridley & Grime, ; Rudman et al, ) evaluated the impact of evolution in multiple species at once, hence supporting our claim that a key frontier in eco‐evolution is the effect of multi‐species evolution on ecology. The study that comes closest to the most realistic experiment is the work of Fridley and Grime () on how genetic variation in multiple species affected species diversity in a grass community.…”

Ionome and elemental transport kinetics shaped by parallel evolution in threespine stickleback

“…; Rudman et al . ; Matthews et al . ; Rudman & Schluter ), including work demonstrating that population‐level differences can affect nutrient recycling (El‐Sabaawi et al .…”

Importance of Riparian Zone: Effects of Resource Availability at Land-water Interface

“…However, ecosystems around the world are increasingly impacted by human landscape disturbances, such as land use, climate change and invasive species, so that cross-ecosystem subsidies should be impacted by these changes [119,127]. Understanding how ecological and physical processes of resource subsidies respond to these changes needs interdisciplinary research approaches, including ecohydrology and ecogeomorphlogy [185], as well as ecological stoichiometry [186] and community and ecosystem genetics [187,188]. In addition, land use, climate change and invasive species always interact with each other, and weaken or strengthen the effects on ecosystem functioning and subsidy dynamics, thus complicate the ecological interaction of food webs.…”