Three brown frog species in Denmark have different abilities to colonise new ponds

For 29 consecutive years, the populations of three species of brown frogs, Rana arvalis, R. dalmatina and R. temporaria, were monitored in an open area in South Zealand, Denmark, with no direct influence of agriculture. Population sizes were recorded by counting egg clumps and showed large variations from year to year. The total population of R. arvalis differed by a factor of 100 between the years with the lowest and the highest numbers. A total of 19 initially unoccupied suitable waterbodies could potentially be colonised by the frogs. Rana dalmatina colonised all of the ponds, mostly in the very first year of existence. Rana arvalis colonised 17 ponds after an average of 10.5 years. Rana temporaria colonised eight ponds after an average of 13.4 years. Colonisation by R. dalmatina was independent of changes in total population size, whereas colonisation by R. arvalis predominantly occurred in years with considerable population increases. The results are discussed in relation to the movement patterns and philopatry of juvenile frogs of the three species. Juvenile R. dalmatina disperse far from the breeding site, but most individuals return to their natal site. This allows the species to be an efficient coloniser of new waterbodies and, at the same time, to have stable occurrence at the original site. The two other species show a more erratic type of dispersal and especially R. temporaria often shifts breeding site from year to year

A systematic survey of regional multi-taxon biodiversity:evaluating strategies and coverage

Abstract Background In light of the biodiversity crisis and our limited ability to explain variation in biodiversity, tools to quantify spatial and temporal variation in biodiversity and its underlying drivers are critically needed. Inspired by the recently published ecospace framework, we developed and tested a sampling design for environmental and biotic mapping. We selected 130 study sites (40 × 40 m) across Denmark using stratified random sampling along the major environmental gradients underlying biotic variation. Using standardized methods, we collected site species data on vascular plants, bryophytes, macrofungi, lichens, gastropods and arthropods. To evaluate sampling efficiency, we calculated regional coverage (relative to the known species number per taxonomic group), and site scale coverage (i.e., sample completeness per taxonomic group at each site). To extend taxonomic coverage to organisms that are difficult to sample by classical inventories (e.g., nematodes and non-fruiting fungi), we collected soil for metabarcoding. Finally, to assess site conditions, we mapped abiotic conditions, biotic resources and habitat continuity. Results Despite the 130 study sites only covering a minute fraction (0.0005%) of the total Danish terrestrial area, we found 1774 species of macrofungi (54% of the Danish fungal species pool), 663 vascular plant species (42%), 254 bryophyte species (41%) and 200 lichen species (19%). For arthropods, we observed 330 spider species (58%), 123 carabid beetle species (37%) and 99 hoverfly species (33%). Overall, sample coverage was remarkably high across taxonomic groups and sufficient to capture substantial spatial variation in biodiversity across Denmark. This inventory is nationally unprecedented in detail and resulted in the discovery of 143 species with no previous record for Denmark. Comparison between plant OTUs detected in soil DNA and observed plant species confirmed the usefulness of carefully curated environmental DNA-data. Correlations among species richness for taxonomic groups were predominantly positive, but did not correlate well among all taxa suggesting differential and complex biotic responses to environmental variation. Conclusions We successfully and adequately sampled a wide range of diverse taxa along key environmental gradients across Denmark using an approach that includes multi-taxon biodiversity assessment and ecospace mapping. Our approach is applicable to assessments of biodiversity in other regions and biomes where species are structured along environmental gradient

Data from: Vascular plant species richness and bioindication predict multi‐taxon species richness

Plants regulate soils and microclimate, provide substrate for heterotrophic taxa, are easy to observe and identify and have a stable taxonomy, which strongly justifies their use as indicators in monitoring and conservation. However, there is no consensus as to whether plants are strong predictors of total multi‐taxon species richness. In this study, we investigate if general terrestrial species richness can be predicted by vascular plant richness and bioindication. To answer this question, we collected an extensive dataset on species richness of vascular plants, bryophytes, macrofungi, lichens, plant‐galling arthropods, gastropods, spiders, carabid beetles, hoverflies, and genetic richness (operational taxonomic units = OTUs) from environmental DNA metabarcoding. We also constructed a Conservation Index based on threatened red list species. Besides using richness of vascular plants for prediction of other taxonomic groups, we also used plant‐derived calibration of the abiotic environment (moisture, soil fertility and light conditions) as well as the degree of anthropogenic impact. Bivariate relationships between plant species richness and other species groups showed no consistent pattern. After taking environmental calibration by bioindication into account, we found a consistent, and for most groups significant, positive effect of plant richness. Plant species richness was also important for richness of fungal OTUs, Malaise OTUs and for the Conservation Index. Our multiple regression analyses revealed (a) a consistently positive effect of plant richness on other taxa, (b) prediction of 12%–55% of variation in other taxa and 48% of variation in the total species richness when bioindication and plant richness were used as predictors. Our results justify that vascular plants are strong indicators of total biodiversity across environmental gradients and broad taxonomic realms and therefore a natural first choice for biodiversity monitoring and conservation planning

Brunbjerg et al. 2018 Methods in Ecology and Evolution

This tab separated data file contains all variables used in the paper