Supplementary information files for Regional occupancy increases for widespread species but decreases for narrowly distributed species in metacommunity time series

Supplementary files for article Regional occupancy increases for widespread species but decreases for narrowly distributed species in metacommunity time series   While human activities are known to elicit rapid turnover in species composition through time, the properties of the species that increase or decrease their spatial occupancy underlying this turnover are less clear. Here, we used an extensive dataset of 238 metacommunity time series of multiple taxa spread across the globe to evaluate whether species that are more widespread (large-ranged species) differed in how they changed their site occupancy over the10-90 years the metacommunities were monitored relative to species that are more narrowly distributed (small-ranged species). We found that on average, large-ranged species tended to increase in occupancy through time, whereas small-ranged species tended to decrease. These relationships were stronger in marine than in terrestrial and freshwater realms. However, in terrestrial regions, the directional changes in occupancy were less extreme in protected areas. Our findings provide evidence for systematic decreases in occupancy of small-ranged species, and that habitat protection could mitigate these losses in the face of environmental change.</p

hinkley

This spreadsheet includes the annual abundance data for fish at Hinkley Point in the Bristol Channel collected between 1981 and 2012. Each monthly sample was collected using the same effort and method. For methods see: Henderson & Holmes (1990). Population stability over a ten year period in the short-lived fish Liparis liparis. J. Fish Biol. 37, 605-615. Henderson & Holmes (1991). On the population dynamics of dab, sole and flounder in the lower Severn estuary, England. Neth. J. Sea Res. 27 (3/4), 337-344. Henderson, James & Holmes (1992). Trophic structure within the Bristol Channel: seasonality and stability in Bridgwater Bay. J. Mar. Biol. Ass. UK. 71, 675-690. Bamber, R.N. & Henderson, P. A. (1994). Seasonality of caridean decapod and mysid distribution and movements within the Severn Estuary and Bristol Channel. Biol. J. Lin. Soc. 51, 83-91. Henderson, P. A. & Seaby, R. M. H. (1994). On the factors influencing juvenile flat fish abundance in the lower Severn Estuary. Neth. J. Sea Res. 33; 321-330. Henderson, P. A. & Seaby, R. M. H. (1999). Population stability of the sea snail at the southern edge of its range. J. Fish Biol. 54, 1161-1176

Local biodiversity change reflects interactions among changing abundance, evenness, and richness

Biodiversity metrics often integrate data on the presence and abundance of multiple species. Yet understanding covariation of changes to the numbers of individuals, the evenness of species relative abundances, and the total number of species remains limited. Using individual-based rarefaction curves, we introduce a conceptual framework to understand how expected positive relationships among changes in abundance, evenness and richness arise, and how they can break down. We then examined interdependencies between changes in abundance, evenness and richness in more than 1100 assemblages sampled either through time or across space. As predicted, richness changes were greatest when abundance and evenness changed in the same direction, and countervailing changes in abundance and evenness acted to constrain the magnitude of changes in species richness. Site-to-site differences in abundance, evenness, and richness were often decoupled, and pairwise relationships between spatial variation in these components across assemblages were weak. In contrast, changes in species richness and relative abundance were strongly correlated for assemblages varying through time. Temporal changes in local biodiversity showed greater inertia and stronger relationships between the component changes when compared to site-to-site variation. Overall, local variation in assemblage diversity was rarely due to a passive sample from a more or less static species abundance distribution. Instead, changing species relative abundances often dominated local variation in diversity. Moreover, how changing relative abundances combined with changes to total abundance frequently determined the magnitude of richness changes. Embracing the interdependencies between changing abundance, evenness and richness can provide new information for better understanding biodiversity change in the Anthropocene.</p

Regional occupancy increases for widespread species but decreases for narrowly distributed species in metacommunity time series

While human activities are known to elicit rapid turnover in species composition through time, the properties of the species that increase or decrease their spatial occupancy underlying this turnover are less clear. Here, we used an extensive dataset of 238 metacommunity time series of multiple taxa spread across the globe to evaluate whether species that are more widespread (large-ranged species) differed in how they changed their site occupancy over the10-90 years the metacommunities were monitored relative to species that are more narrowly distributed (small-ranged species). We found that on average, large-ranged species tended to increase in occupancy through time, whereas small-ranged species tended to decrease. These relationships were stronger in marine than in terrestrial and freshwater realms. However, in terrestrial regions, the directional changes in occupancy were less extreme in protected areas. Our findings provide evidence for systematic decreases in occupancy of small-ranged species, and that habitat protection could mitigate these losses in the face of environmental change.</p