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- Unravelling the complexities of biotic homogenization and heterogenization in the British avifaunaPublication . Wayman, Joseph P.; Sadler, Jonathan P.; Martin, Thomas E; Graham, Laura J; White, Hannah J; Tobias, Joseph; Matthews, Thomas J.Biotic homogenization is a process whereby species assemblages become more similar through time. The standard way of identifying the process of biotic homogenization is to look for decreases in spatial beta–diversity. However, using a single assemblage-level metric to assess homogenization can mask important changes in the occupancy patterns of individual species. Here, we analysed changes in the spatial beta–diversity patterns (i.e. biotic heterogenization or homogenization) of British bird assemblages within 30 km × 30 km regions between two periods (1988–1991 and 2008–2011). We partitioned the change in spatial beta–diversity into extirpation and colonization-resultant change (i.e. change in spatial beta–diversity within each region resulting from both extirpation and colonization). We used measures of abiotic change in combination with Bayesian modelling to disentangle the drivers of biotic heterogenization and homogenization. We detected both heterogenization and homogenization across the two time periods and three measures of diversity (taxonomic, phylogenetic, and functional). In addition, both extirpation and colonization contributed to the observed changes, with heterogenization mainly driven by extirpation and homogenization by colonization. These assemblage-level changes were primarily due to shifting occupancy patterns of generalist species. Compared to habitat generalists, habitat specialists had significantly (i) higher average contributions to colonization-resultant change (indicating heterogenization within a region due to colonization) and (ii) lower average contributions to extirpation-resultant change (indicating homogenization from extirpation). Generalists showed the opposite pattern. Increased extirpation-resultant homogenization within regions was associated with increased urban land cover and decreased habitat diversity, precipitation, and temperature. Changes in extirpation-resultant heterogenization and colonization-resultant heterogenization were associated with differences in elevation between regions and changes in temperature and land cover. Many of the ‘winners’ (i.e. species that increased in occupancy) were species that had benefitted from conservation action (e.g. buzzard (Buteo buteo). The ‘losers’ (i.e. those that decreased in occupancy) consisted primarily of previously common species, such as cuckoo (Cuculus canorus). Our results show that focusing purely on changes in spatial beta–diversity over time may obscure important information about how changes in the occupancy patterns of individual species contribute to homogenization and heterogenization.
- Biological knowledge shortfalls impede conservation efforts in poorly studied taxa—A case study of LaboulbeniomycetesPublication . Haelewaters, Danny; Matthews, Thomas J.; Wayman, Joseph P.; CAZABONNE, Jonathan; Heyman, Felix; Quandt, C. Alisha; Martin, Thomas EABSTRACT: Most empirical research on biological shortfalls has focused on vertebrate taxa. This is important given many species in poorly studied groups such as invertebrates, plants, and fungi are predicted to possess high conservation risk. Here, we focus on Laboulbeniomycetes: a class of microfungi that are understudied. We examined four shortfalls: Linnean (knowledge gaps in species diversity), Wallacean (knowledge gaps in distributions), Latimerian (knowledge gaps in species persistence), and the newly introduced Scottian (knowledge gaps in species conservation assessments) shortfalls. The Linnean shortfall in Laboulbeniomycetes is hard to predict due to inconsistent spe-cies description rates. Analysis of distribution patterns indicates Laboulbeniomycetes are likely to experience an extremely high Wallacean shortfall, with many species hav-ing highly disjunct known distributions. Latimerian shortfall analysis shows over half (51%) of Laboulbeniomycetes have not been recorded in >50 years, while the group has a collective Scottian shortfall of 100%, given none of the 2454 described species have received an IUCN threat assessment. We suggest continued study of natural his-tory collections, expanded citizen science programmes, and machine- learning iden-tification approaches as important tools for reducing knowledge shortfalls in both Laboulbeniomycetes and poorly studied taxa more generally.