Resilience of insect assemblages to climate change in mature temperate mountain forests of NE China

The turnover patterns in species assemblages along gradients of abiotic or biotic conditions are indicative of the assemblages’ sensitivity to changes in these conditions. Studies of such gradients allow an evaluation of the degree of habitat specialization in different taxa, which will strongly affect their ability to react to changes in climatic conditions. Our study was carried at one of the largest mature temperate forests in northeastern China, Changbai Mountain. We establish how strongly shifts in the assemblages of two mega-diverse insect families, ground beetles and geometrid moths, are associated with changes in the vegetation that are indicative of the degree of habitat specialization, in comparison to altitudinal change that is linked to changes in both temperature and precipitation. Overall, altitudinal change exerted a substantially stronger influence on insect species turnover patterns than vegetation changes, with elevation being particularly strongly linked to turnover in carabid and dominant geometrid species. Significant links were recorded between changes in the vegetation and turnover in both insect taxa, but Partial Mantel Tests reveal that the observed links with the vegetation are partly indirect. The results indicate that many species in both taxa are habitat generalists able to thrive in a wide range of plant species assemblages and vegetation structures. This will facilitate climate change-induced shifts in their distribution ranges. Conservation efforts should therefore be strongly focused on the smaller groups of habitat- and host-plant insect specialists, as well as on assemblages associated with mountain top habitats that will be unable to shift their ranges further upward.