A metacommunity approach (objective 3)

Tornero et al. (2018) – Plos ONE, 13:e0203119.
By means of the distance-decay relationship, we compared the relative role of the local environmental structuring and the regional control in pond metacommunities with different spatial extent. We tested it by studying the community similarity among three biotic groups with different dispersal modes (macrofaunal active and passive dispersers and plants) from two pond networks largely differing in extent. Overall, we found that environmental distance had larger effects than geographical distances in both pond networks. Species sorting is the main type of metacommunity dynamics shaping all biotic groups in a large network, but when spatial extend is smaller differences arise among biotic groups. While the distance-decay patterns of active dispersers better fit the trend expected under mass effect dynamics, passive dispersers suggest the prevalence of a species sorting pattern.

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Cunillera-Montcusí et al. (2019) – Freshwater Biology, 64:323–334.

Taking advantage of a wildfire that partially affected a Mediterranean temporary pond network, we analysed wildfire impacts on faunal communities adapted to temporality by comparing the environmental and the faunal community responses from before and after the wildfire, and between the burned and unburned ponds during the subsequent hydroperiod. We focused on species traits related to expected indirect and direct impacts (i.e. dispersal ability, life history or feeding habits). We found changes in abundances of some trophic groups from before and after the wildfire, strong fluctuations at the beginning of the hydroperiod between burned and unburned ponds as well as a decrease in abundance of organisms that remain in the pond sediment during drought in burned ponds. However, only one hydroperiod appears to be sufficient for burned ponds to recover their similarity to unburned ponds, which highlights the high resilience of these communities.

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Cunillera-Montcusí et al. (2020) – Journal of Animal Ecology, 89:2134-2144.

We examined the relative roles of wildfire disturbance, local conditions and successional dynamics on the assembly of aquatic macroinvertebrate communities in a Mediterranean temporary pond metacommunity. We used the theory of community assembly by trait selection (CATS) to identify traits under selection and to estimate their dependence on wildfire disturbance and environmental gradients. We found that local environmental conditions and successional dynamics had greater relevance in the selection of traits than the wildfire. Our results evidenced the strong relevance of successional changes in trait-mediated assembly mechanisms and its interplay with wildfire disturbance in temporary pond communities.

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Cunillera-Montcusí et al. (2021) – Ecography, 44(7): 1022-1034.

We applied a lottery model that considers landscape alteration and species dispersal abilities to analyse biodiversity resilience to increasing intensity wildfire disturbances in a pond macroinvertebrate metacommunity. We evaluated metacommunity recovery across gradients of wildfire size (area) and intensity (% of burned communities). Our simulated responses reported a highly resilient system. However, our model identified non-linear relationships between fire intensity and resilience. When fire intensity affects more than half of the landscape the network becomes fragmented, breaking stepping-stone recolonization dynamics for some dispersal groups and compromising recolonization from unburned or recolonized sites.

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Tornero et al. (submitted)

We tested the role of network centrality metrics (‘degree’, ‘betweenness’ and ‘closeness’) and environmental characteristics in the biodiversity patterns of pond macroinvertebrate metacommunities (four pond networks) at local and regional scales. Different centrality metrics capturing connectivity at different spatial scales affect pond biodiversity values. Overall, regional biodiversity metrics show similar patterns in all of the networks studied mainly in response to connectivity, whereas local biodiversity metrics show less general but more network-dependent patterns, responding the latest mostly to environmental characteristics. Thus, the degree of connectance of a node in a network with no directional connectivity affects biodiversity.

 

 

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Cunillera-Montcusí et al. (in press) Inland Waters.

We combined a network analysis approach with a mesocosms experiment to disentangle how large-scale and small-scale regional factors influence dispersal dynamics in a pond macroinvertebrate metacommunity. We set up several mesocosms around two source ponds with divergent locations within the network centrality–isolation gradient, at different distances and in different directions. The large scale, being central or isolated, determined abundance and richness across the hydroperiod, with greater values in central locations. However, this general pattern can be modulated by smaller regional factors and by intrinsic taxa dispersal ability.

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