Meta-analysis of multidecadal biodiversity trends in Europe

Abstract

Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15-91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe.

Fig. 1. Distribution of the time series across biogeoregions, realms and taxonomic groups.

a Relative distribution of studied taxonomic groups across biogeoregions (magenta dots: study sites). Note that the most south-eastern site (in Israel) belongs to the Mediterranean region. b Relative distribution of studied taxonomic groups and biogeoregions across realms. c Relative distribution of studied biogeoregions across taxonomic groups. FW freshwater, MA marine and transitional zone, TE terrestrial, Alg benthic algae, Bir birds, InvA aquatic invertebrates, InvT terrestrial invertebrates, Mam mammals, Pl plankton, Pla terrestrial plants. The pie charts show the proportion of taxonomic groups for each biogeoregion and realm, and the proportion of biogeoregions for each realm and taxonomic group. The shapefiles of the biogeographical regions and marine subregions were obtained from EEA. Drawings of taxonomic groups are from phylopic.org. Source data are provided as a Source Data file.

Fig. 2. Biodiversity trends in the different biogeoregions.

The results of meta-analysis mixed models are shown for the four studied biodiversity metrics: abundance (a), richness (b), diversity (c) and turnover (d). Green: significant increasing trends (p ≤ 0.05); orange: significantly declining trends (p ≤ 0.05); black (dark grey for Adriatic Sea): no significant trends (p > 0.05). For biogeoregion identity see Fig. 1. e Values of S-statistics (model estimated mean, error bar: +/− C.I.). Adr: Adriatic (n = 1 time series), Alp: Alpine (n = 33 time series), Atl Atlantic (n = 56 time series), BlS Black Sea (n = 5 time series), Bor Boreal (n = 32 time series), Con Continental (n = 17 time series), Med Mediterranean (n = 9 time series), NoS North Sea (n = 7 time series), and Pan Pannonian (n = 1 time series). Dark blue: abundance, pink: richness, yellow: diversity, light blue: turnover. Solid line and dot: p ≤ 0.05; dashed line and open circle: p > 0.05. Source data are provided as a Source Data file.

Fig. 3. Biodiversity trends in the three realms.

The results of meta-analysis mixed models are shown for the four studied biodiversity metrics: abundance (a), richness (b), diversity (c) and turnover (d). Green: significant increasing trends (p ≤ 0.05); black: no significant trends (p > 0.05). e Values of S-statistics (model estimated mean, error bar: +/−C.I.). Dark blue: abundance, pink: richness, yellow: diversity, light blue: turnover. Solid line and dot: p ≤ 0.05; dashed line and open circle: p > 0.05. FW freshwater (n = 51 time series); MA marine and transitional zones (n = 18 time series); TE terrestrial (n = 92 time series). Source data are provided as a Source Data file.

Fig. 4. Biodiversity trends for the studied taxonomic groups.

The results of meta-analysis mixed models are shown for the four studied biodiversity metrics: abundance (a), richness (b), diversity (c) and turnover (d). Green: significant increasing trends (p ≤ 0.05); orange: significant declining trends (p ≤ 0.05); black: no significant trends (p > 0.05). Drawings from phylopic.org. e values of S-statistics (model estimated mean, error bar: +/−C.I.). Dark blue: abundance, pink: richness, yellow: diversity, light blue: turnover. Solid line and dot: p ≤ 0.05; dashed line and open circle: p > 0.05. Number of time series (n): Plants: 34, terrestrial invertebrates: 53, mammals: 1, birds: 16, benthic algae: 7, plankton: 9, aquatic invertebrates: 38, fish: 3. Source data are provided as a Source Data file.