Community disassembly under global change: Evidence in favor of the stress‐dominance hypothesis. (11th June 2018)

• Record Type: Journal Article
• Authors: Kuczynski, Lucie; Grenouillet, Gaël
• Is Part Of: Global change biology. Volume 24:Number 9(2018)
• Page Start: 4417
• Page End: 4427
• Publication Date: 2018-06-11
• Subjects: assembly rules -- biological invasion -- climate change -- community reassembly -- functional diversity -- long‐term change -- phylogenetic diversity -- stream fish community; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.14320
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Ecological theory suggests that communities are not random combinations of species but rather the results of community assembly processes filtering and sorting species that are able to coexist together. To date, such processes (i.e., assembly rules) have been inferred from observed spatial patterns of biodiversity combined with null model approaches, but relatively few attempts have been made to assess how these processes may be changing through time. Specifically, in the context of the ongoing biodiversity crisis and global change, understanding how processes shaping communities may be changing and identifying the potential drivers underlying these changes become increasingly critical. Here, we used time series of 460 French freshwater fish communities and assessed both functional and phylogenetic diversity patterns to determine the relative importance of two key assembly rules (i.e., habitat filtering and limiting similarity) in shaping these communities over the last two decades. We aimed to (a) describe the temporal changes in both functional and phylogenetic diversity patterns, (b) determine to what extent temporal changes in processes inferred through the use of standardized diversity indices were congruent, and (c) test the relationships between the dynamics of assembly rules and both climatic and biotic drivers. Our results revealed that habitat filtering, although already largely predominant over limiting similarity, became more widespread over time. We also highlighted that phylogenetic and trait‐based approaches offered complementary information about temporal changes in assembly rules. Finally, we found that increased environmental harshness over the study period (especially higher seasonality of temperature) led to an increase in habitat filtering and that biological invasions increased functional redundancy within communities. Overall, these findings underlie the need to develop temporal perspectives in community assembly studies, as understanding ongoing temporal changes could provide a better vision about the way communities could respond to future global changes. Abstract : Changes in standardized effect sizes (SES) for functional diversity over time. Positive values of SES indicate higher diversity than expected given the number of species, revealing limiting similarity (LS) as the main process shaping community. Negative values of SES indicate lower diversity than expected given the species richness, meaning that habitat filtering (HF) is the major process shaping community structure. By contrasting historical ( x ‐axis) and contemporary ( y ‐axis) SES values and the sign of the temporal trends (negative, below the x : y line or positive, above the x : y line), six categories of temporal trends can be defined.