Retos20_RIVSTRESS

Multiple stressors impacting rivers: community and ecosystem function (RIVSTRESS)

Global Change promotes the emergence of stress factors that affect river ecosystems and impact their biodiversity and functions, with implications for the services they provide to society.

RIVSTRESS will define the effect of some of the most frequent stressors in Mediterranean waterways (eg water stress, higher water temperature, excess nutrients, pesticides). The project will investigate its effects when
i) their order of appearance differs, from less intense to more intense, or vice versa;
ii) their co-occurrence is not linear, but as it happens in nature it can reach the ecosystems in the form of pulsations, increasing ramps, or continuous pressures;
iii) its effects are conditioned by the impacts associated with the presence of previous stressors, which can cause inherited effects.

Some observable situations in the field will be used to define in situ the response of these stress factors, as well as experiments designed in micro- or mesocosms, to understand the generality of these responses and their associated mechanisms. RIVSTRESS aims to define how the different sequences of stress factors affecting river ecosystems can affect the structure of the community (community composition; functional diversity; alpha and beta diversity), its resistance to these stressors and their specific dynamics of occurrence, and the ability they may have to recover once these impacts no longer act on the system.

To do this, a set of variables will be used throughout the river’s biological organization. Microorganisms (bacteria, algae, fungi) and invertebrates will be analyzed, on which a complete set of structural and functional descriptors will be determined, and they will be related to the most relevant functions performed by fluvial ecosystems. Among these, we will consider those associated with the ecosystem service of water purification, that is, the decomposition of organic matter and the removal of nutrients, and other related functions (primary production, respiration, energy transfer in the food chain ).

With all this, RIVSTRESS will draw up recommendations that will allow us to anticipate the magnitude of the effects that the multiple stressors may cause to the fluvial ecosystems subjected to Global Change.