Modelling the distribution and compositional variation of plant communities at the continental scale

Abstract

Aim We investigate whether (1) environmental predictors allow to delineate the distribution of discrete community types at the continental scale and (2) how data completeness influences model generalization in relation to the compositional variation of the modelled entities. Location Europe. Methods We used comprehensive datasets of two community types of conservation concern in Europe: acidophilous beech forests and base‐rich fens. We computed community distribution models (CDMs) calibrated with environmental predictors to predict the occurrence of both community types, evaluating geographical transferability, interpolation and extrapolation under different scenarios of sampling bias. We used generalized dissimilarity modelling (GDM) to assess the role of geographical and environmental drivers in compositional variation within the predicted distributions. Results For the two community types, CDMs computed for the whole study area provided good performance when evaluated by random cross‐validation and external validation. Geographical transferability provided lower but relatively good performance, while model extrapolation performed poorly when compared with interpolation. Generalized dissimilarity modelling showed a predominant effect of geographical distance on compositional variation, complemented with the environmental predictors that also influenced habitat suitability. Main conclusions Correlative approaches typically used for modelling the distribution of individual species are also useful for delineating the potential area of occupancy of community types at the continental scale, when using consistent definitions of the modelled entity and high data completeness. The combination of CDMs with GDM further improves the understanding of diversity patterns of plant communities, providing spatially explicit information for mapping vegetation diversity and related habitat types at large scales.

Distribution modelling of vegetation types based on area frame survey data

“…This demonstrates a high potential of distribution modelling methods also for prediction of community‐level entities such as VTs, even at very high resolutions and for broad extents, given that appropriate predictor data are available (see Figure , for example). Our results are in accordance with other DM studies, operating with targets above species level, and on similar or larger spatial domains (Jiménez‐Alfaro et al., ; Mücher et al., ). Jiménez‐Alfaro et al.…”

“…Jiménez‐Alfaro et al. () also showed that DM of community‐level targets is a significant improvement to existing vegetation maps over the European continent, supplementing under‐sampled areas.…”

Plant distribution, stature, rarity, and diversity in a patterned calcareous fen: tests of geochemical and leaf‐height models

“…Changes in fen vegetation over the past few decades have raised conservation concerns in Europe and North America (Verhoeven et al., ; Jacobson et al., ; Fojt, ; van Diggelen et al., , ; Jímenez‐Alfaro et al., ) and have been variously ascribed to eutrophication, invasive species, or changes in hydrology or disturbance regime. The relative importance of hydrology and traditional management activities (mowing, grazing, burning, turf cutting) has been much debated, especially in Europe (Fojt and Harding, ; Opdekamp et al., ).…”

Defining and applying the concept of Favourable Reference Values for species habitats under the EU Birds and Habitats Directives : technical report

“…Spatial habitat modelling (SHM) for settings FRVs of habitat types (continued) Suitability maps can be used to estimate range parameters (i.e. environmental driver) as well, such as the area of occupancy, useful for assessing the conservation status at both regional and continental (Jiménez-Alfaro et al, 2018; scales. • terrestrial mammals (Table A2.1);…”