Recent composition changes of forest assemblages predictable by climate and land cover velocity metrics

Background/Question/Methods

Mapping the environmental changes likely to be experienced in the near future can be used to determine those areas where substantial compositional shifts and novel ecosystems are to be expected. However, tests of these spatially-explicit hypothesises of ecological change are rare. Here, two metrics of environmental change (speed estimates and standardized effect sizes) are used to identify where recent changes in extreme climatic conditions and land cover could result in generalised ecological rearrangements. These predictions were tested using observed compositional shifts in North American forests.

Results/Conclusions

Globally, median speeds of climate-extremes and land-cover isoclines movement were 12.55 and 0.016km×yr−1 during the last 20-years respectively; with climate-spells length and anthropogenic land-classes cover increasing during this period. While boreal grasslands/shrublands, and temperate forests showed the most severe changes in extreme climatic conditions; montane grasslands, and (sub)tropical forests experienced the most substantial fluctuations in land cover.North American forests with fast climatic and land-cover speeds were those with the most substantial compositional changes, indicating the appropriateness of environmental estimates of change to represent ecological arrangements.The approach used here can be used to determine potential ecological rearrangements and identify conservation and management strategies to the threats of an anthropogenic future.