A multidimensional framework for measuring biotic novelty: How novel is a community?. (29th May 2020)

• Record Type: Journal Article
• Authors: Schittko, Conrad; Bernard‐Verdier, Maud; Heger, Tina; Buchholz, Sascha; Kowarik, Ingo; von der Lippe, Moritz; Seitz, Birgit; Joshi, Jasmin; Jeschke, Jonathan M.
• Is Part Of: Global change biology. Volume 26:Number 8(2020)
• Page Start: 4401
• Page End: 4417
• Publication Date: 2020-05-29
• Subjects: alien species -- biological invasions -- coexistence -- ecological novelty -- functional diversity -- novel ecosystems -- novel species -- standard metrics; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.15140
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Anthropogenic changes in climate, land use, and disturbance regimes, as well as introductions of non‐native species can lead to the transformation of many ecosystems. The resulting novel ecosystems are usually characterized by species assemblages that have not occurred previously in a given area. Quantifying the ecological novelty of communities (i.e., biotic novelty) would enhance the understanding of environmental change. However, quantification remains challenging since current novelty metrics, such as the number and/or proportion of non‐native species in a community, fall short of considering both functional and evolutionary aspects of biotic novelty. Here, we propose the Biotic Novelty Index (BNI), an intuitive and flexible multidimensional measure that combines (a) functional differences between native and non‐native introduced species with (b) temporal dynamics of species introductions. We show that the BNI is an additive partition of Rao's quadratic entropy, capturing the novel interaction component of the community's functional diversity. Simulations show that the index varies predictably with the relative amount of functional novelty added by recently arrived species, and they illustrate the need to provide an additional standardized version of the index. We present a detailed R code and two applications of the BNI by (a) measuring changes of biotic novelty of dry grassland plant communities along an urbanization gradient in a metropolitan region and (b) determining the biotic novelty of plant species assemblages at a national scale. The results illustrate the applicability of the index across scales and its flexibility in the use of data of different quality. Both case studies revealed strong connections between biotic novelty and increasing urbanization, a measure of abiotic novelty. We conclude that the BNI framework may help building a basis for better understanding the ecological and evolutionary consequences of global change. Abstract : Anthropogenic changes in climate, land use and disturbance regimes, as well as introductions of non‐native species are generating novel communities composed of new combinations of species. Quantifying this biotic novelty of communities in a standardized and comparable manner would enhance our understanding of environmental change. We propose the Biotic Novelty Index (BNI), an intuitive and flexible multidimensional measure that combines (a) functional differences between native and non‐native species with (b) the temporal dynamics of species introductions. We present a detailed R code, extensive simulations and two applications to illustrate the applicability of the BNI.