Comedi


The response of aquatic communities to disturbances in Mediterranean shallow lakes

FUNDING

Ministerio de Economía, Industria y Competitividad

Programa Estatal de I+D+i Orientada a los Retos de la Sociedad

Ref. CGL2016-76024-R (AEI / FEDER /UE)

BACKGROUND

Disturbances in shallow lakes in the Mediterranean area, such as flooding events, are usually pulse-type, after which productivity (production / biomass) and resource availability tend to diminish. Other non-hydric disturbances in the Mediterranean region, such as wildfires, are also pulse type. Aquatic communities should be adapted to a decrease in nutrient availability with time as well as to an increase in organisms’ concentration coinciding with the decrease in water level. Anthropogenic activities usually cause more gradual or permanent press-type changes in these shallow lakes, such as changes in the hydrological regime or eutrophication by nutrient inputs. Since these disturbances are mainly of human origin, we start from the assumption that aquatic communities of these shallow lakes are resilient to pulse disturbances and adapted to the diminution of resource availability that occurs after them. Resilience also appears at metacommunity scale, since under natural conditions, communities that colonize these aquatic environments are distributed in networks of more or less connected water bodies. On the other hand, these communities would be more sensitive to gradual nutrient inputs, usually of anthropogenic origin, that provide nutrients over a long period of time and increases productivity and resource availability. Gradual changes would have a setback on the successional pattern and would cause that community structure do not follow the characteristic pattern, favouring species with more opportunistic strategies.

In this project we compare the response of aquatic communities to pulse type disturbances and to gradual nutrient inputs with the aim to determine if there are regularities between community structure and productivity and resource availability. We also analyse these responses at a metacommunity scale, comparing systems with lesser or greater degree of connectivity. We develop this studies in two types of Mediterranean lentic ecosystems: coastal lagoons (objectives 1 and 2) and temporary ponds (objective 3). Both are included in the Habitats Directive of the European Commission (Council Directive 92/43/EEC, Annex 1) as priority natural habitat types of community interest.

HYPOTHESES AND OBJECTIVES

General objective: To determine the response of the aquatic community to pulse type (such as flooding events or wild fires) and press type (such as gradual changes in nutrient availability) disturbances.

Working hypothesis: that aquatic communities of Mediterranean lenitic environments is highly resilient to intense pulsatile disturbances, as long as the metacommunity structure is maintained with some degree of connectivity between waterbodies, and is adapted to the trend of decreasing resource availability that occurs after such a disturbance. These aquatic communities are, on the other hand, very sensitive to the gradual inputs of nutrients, generally of anthropic origin, which maintain high productivity and availability of resources over time.

Specific objectives:

1. To determine the metabolism of Mediterranean shallow lakes and to verify the relationship between disturbances, productivity and community structure (Hydrology and ecosystem metabolism)

2. To compare the response of the aquatic community in natural and/or man made habitats to pulse or gradual disturbances (Response to disturbances)

3. To model the response of aquatic communities to high intensity pulse disturbances at a metacommunity scale (A metacommunity approach)

PROJECT MAIN RESULTS

Hydrology and ecosystem metabolism (objective 1)

Hydrology and ecosystem metabolism (objective 1)

Groundwater dependence of coastal lagoons: The case of La Pletera salt marshes (NE Catalonia)

Menció et al. (2017) – Journal of Hydrology, 552: 793-806 We describe the hydrological regime of a confined coastal ecosystem...
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Hydrology and ecosystem metabolism (objective 1)

Modeling the salinity fluctuations in salt marsh lagoons

Casamitjana et al. (2019) We evaluated water inflows and outflows and evaporation fluxes in La Pletera salt marsh lagoons by...
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Hydrology and ecosystem metabolism (objective 1)

Ecosystem metabolism dynamics and environmental drivers in Mediterranean confined coastal lagoons

Bas-Silvestre et al. (2020) Metabolic rates in confined lagoons vary seasonally, with high values in summer, characterized by periods of...
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Hydrology and ecosystem metabolism (objective 1)

Effects of water circulation on ecosystem metabolism

Bas-Silvestre et al. (work in progress) We analyse how water circulation affects metabolic rates in confined coastal lagoons. We model...
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Hydrology and ecosystem metabolism (objective 1)

Phytoplankton species composition related to ecosystem metabolism

Bas-Silvestre et al. (work in progress) We determine how productivity affects the community structures by crossing the planktonic species composition...
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Hydrology and ecosystem metabolism (objective 1)

Natural versus man-made mediterranean coastal lagoons: Distinct microbial functioning depending on season

Boadella et al. (submitted) This study compares the microbial heterotrophic functioning in three “new” lagoons (created in 2016) to that...
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Response to  disturbances (objective 2)

Responses to pulse type or press type disturbances (objective 2)

Experiment PC

Meredith et al. (work in progress) We conducted a field experiment of nutrient addition in a coastal lagoon during winter-spring...
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Responses to pulse type or press type disturbances (objective 2)

Identifying critical transitions in seasonal shifts of zooplankton composition in a confined coastal salt marsh

Quintana et al. (submitted) We applied the alternative stable states theory to analyse if seasonal zooplankton shifts behave as critical...
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A metacommunity approach (objective 3)

A metacommunity approach (objective 3)

Dispersal mode and spatial extent influence distance-decay patterns in pond metacommunities

Tornero et al. (2018) PLoS ONE, 13:e0203119. By means of the distance-decay relationship, we compared the relative role of the...
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A metacommunity approach (objective 3)

Direct and indirect impacts of wildfire on faunal communities of Mediterranean temporary ponds

Cunillera-Montcusí et al. (2019) Freshwater Biology, 64:323–334. Taking advantage of a wildfire that partially affected a Mediterranean temporary pond network,...
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A metacommunity approach (objective 3)

Addressing trait selection patterns in temporary ponds in response to wildfire disturbance and seasonal succession

Cunillera-Montcusí et al. (2020) Journal of Animal Ecology, 89:2134-2144. We examined the relative roles of wildfire disturbance, local conditions and...
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A metacommunity approach (objective 3)

Resilience tipping points in pond metacommunities against simulated wildfires are mediated by the network structure and species dispersal ability

Cunillera-Montcusí et al. (submitted) We applied a lottery model that considers landscape alteration and species dispersal abilities to analyse biodiversity...
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A metacommunity approach (objective 3)

Determining the effects of network connectivity on biodiversity patterns in macroinvertebrate metacommunities

Tornero et al. (submitted) We tested the role of network centrality metrics (‘degree’, ‘betweenness’ and ‘closeness’) and environmental characteristics in...
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A metacommunity approach (objective 3)

Large- and small-regional-scale variables interact in the dispersal patterns of aquatic macroinvertebrates from temporary ponds

Cunillera-Montcusí et al. (in press) Aquatic Ecology. We combined a network analysis approach with a mesocosms experiment to disentangle how...
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