Global Change Effects on Biological Interactions: Nutrient Inputs, Invasive Species, and Multiple Drivers Shape Marine Patagonian Communities

VALIÑAS, M.S; BLUM, R.; GALVÁN, D.; VARISCO, M.; MARTINETTO, P.

Global Change in Atlantic Coastal Patagonian Ecosystems: A Journey Through Time

Springer

Año: 2022; p. 291 - 316

Species are connected with others through different types of interactions (e.g., trophic interactions, facilitation, etc.), thus any effect caused by global change on one species may consequently impact others species by changing the direction and/or the strength of biological interactions. In the present chapter, we provide examples of the impact of some global change drivers that caused significant changes in the composition and the structure of marine Patagonian communities by affecting positive and/or negative species interactions. Examples of the effects of invasive species, increase in nutrient inputs and ultraviolet radiation impact, among others, are provided through the analysis of study cases from the Patagonian coast. Facilitative interactions between sessile invaders and native species are more frequent than interference processes. Also eutrophication directly impacts primary producers by increasing their biomass and/or their growth rates, altering their nutritional quality or causing shifts in species composition, which in turn indirectly affect consumers. Top-down processes involve direct impacts by increased predation pressure on organisms, but also indirect ones through trophic cascades (i.e., by releasing top-down effect on some species). We also show that single species may be benefitted through multiple interactions acting simultaneously in bottom-up and top-down directions. Finally, we point out some current research gaps and provide perspectives for future investigation in order to achieve the best ecological approach to understand how marine ecosystems as a whole are facing global change in Patagonia.