@article{MaihoffFriessHoissetal.2023, author = {Maihoff, Fabienne and Friess, Nicolas and Hoiss, Bernhard and Schmid-Egger, Christian and Kerner, Janika and Neumayer, Johann and Hopfenm{\"u}ller, Sebastian and B{\"a}ssler, Claus and M{\"u}ller, J{\"o}rg and Classen, Alice}, title = {Smaller, more diverse and on the way to the top: Rapid community shifts of montane wild bees within an extraordinary hot decade}, series = {Diversity and Distributions}, volume = {29}, journal = {Diversity and Distributions}, number = {2}, doi = {10.1111/ddi.13658}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312126}, pages = {272-288}, year = {2023}, abstract = {Aim Global warming is assumed to restructure mountain insect communities in space and time. Theory and observations along climate gradients predict that insect abundance and richness, especially of small-bodied species, will increase with increasing temperature. However, the specific responses of single species to rising temperatures, such as spatial range shifts, also alter communities, calling for intensive monitoring of real-world communities over time. Location German Alps and pre-alpine forests in south-east Germany. Methods We empirically examined the temporal and spatial change in wild bee communities and its drivers along two largely well-protected elevational gradients (alpine grassland vs. pre-alpine forest), each sampled twice within the last decade. Results We detected clear abundance-based upward shifts in bee communities, particularly in cold-adapted bumble bee species, demonstrating the speed with which mobile organisms can respond to climatic changes. Mean annual temperature was identified as the main driver of species richness in both regions. Accordingly, and in large overlap with expectations under climate warming, we detected an increase in bee richness and abundance, and an increase in small-bodied species in low- and mid-elevations along the grassland gradient. Community responses in the pre-alpine forest gradient were only partly consistent with community responses in alpine grasslands. Main Conclusion In well-protected temperate mountain regions, small-bodied bees may initially profit from warming temperatures, by getting more abundant and diverse. Less severe warming, and differences in habitat openness along the forested gradient, however, might moderate species responses. Our study further highlights the utility of standardized abundance data for revealing rapid changes in bee communities over only one decade.}, language = {en} } @article{RothHackerHeidrichetal.2021, author = {Roth, Nicolas and Hacker, Herrmann Heinrich and Heidrich, Lea and Friess, Nicolas and Garc{\´i}a-Barroas, Enrique and Habel, Jan Christian and Thorn, Simon and M{\"u}ler, J{\"o}rg}, title = {Host specificity and species colouration mediate the regional decline of nocturnal moths in central European forests}, series = {Ecography}, volume = {44}, journal = {Ecography}, number = {6}, doi = {10.1111/ecog.05522}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258731}, pages = {941-952}, year = {2021}, abstract = {The high diversity of insects has limited the volume of long-term community data with a high taxonomic resolution and considerable geographic replications, especially in forests. Therefore, trends and causes of changes are poorly understood. Here we analyse trends in species richness, abundance and biomass of nocturnal macro moths in three quantitative data sets collected over four decades in forests in southern Germany. Two local data sets, one from coppiced oak forests and one from high oak forests included 125K and 48K specimens from 559 and 532 species, respectively. A third regional data set, representing all forest types in the temperate zone of central Europe comprised 735K specimens from 848 species. Generalized additive mixed models revealed temporal declines in species richness (-38\%), abundance (-53\%) and biomass (-57\%) at the regional scale. These were more pronounced in plant host specialists and in dark coloured species. In contrast, the local coppiced oak forests showed an increase, in species richness (+62\%), while the high oak forests showed no clear trends. Left and right censoring as well as cross validation confirmed the robustness of the analyses, which led to four conclusions. First, the decline in insects appears in hyper diverse insect groups in forests and affects species richness, abundance and biomass. Second, the pronounced decline in host specialists suggests habitat loss as an important driver of the observed decline. Third, the more severe decline in dark species might be an indication of global warming as a potential driver. Fourth, the trends in coppiced oak forests indicate that maintaining complex and diverse forest ecosystems through active management may be a promising conservation strategy in order to counteract negative trends in biodiversity, alongside rewilding approaches.}, language = {en} } @article{HeidrichPinkertBrandletal.2021, author = {Heidrich, Lea and Pinkert, Stefan and Brandl, Roland and B{\"a}ssler, Claus and Hacker, Hermann and Roth, Nicolas and Busse, Annika and M{\"u}ller, J{\"o}rg and Friess, Nicolas}, title = {Noctuid and geometrid moth assemblages show divergent elevational gradients in body size and color lightness}, series = {Ecography}, volume = {44}, journal = {Ecography}, number = {8}, doi = {10.1111/ecog.05558}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256694}, pages = {1169-1179}, year = {2021}, abstract = {Previous macroecological studies have suggested that larger and darker insects are favored in cold environments and that the importance of body size and color for the absorption of solar radiation is not limited to diurnal insects. However, whether these effects hold true for local communities and are consistent across taxonomic groups and sampling years remains unexplored. This study examined the variations in body size and color lightness of the two major families of nocturnal moths, Geometridae and Noctuidae, along an elevational gradient of 700 m in Southern Germany. An assemblage-based analysis was performed using community-weighted means and a fourth-corner analysis to test for variations in color and body size among communities as a function of elevation. This was followed by a species-level analysis to test whether species occurrence and abundance along an elevation gradient were related to these traits, after controlling for host plant availability. In both 2007 and 2016, noctuid moth assemblages became larger and darker with increasing elevation, whereas geometrids showed an opposite trend in terms of color lightness and no clear trend in body size. In single species models, the abundance of geometrids, but not of noctuids, was driven by habitat availability. In turn, the abundance of dark-colored noctuids, but not geometrids increased with elevation. While body size and color lightness affect insect physiology and the ability to cope with harsh conditions, divergent trait-environment relationships between both families underline that findings of coarse-scale studies are not necessarily transferable to finer scales. Local abundance and occurrence of noctuids are shaped by morphological traits, whereas that of geometrids are rather shaped by local habitat availability, which can modify their trait-environment-relationship. We discuss potential explanations such as taxon-specific flight characteristics and the effect of microclimatic conditions.}, language = {en} } @article{HilmersFriessBaessleretal.2018, author = {Hilmers, Torben and Friess, Nicolas and B{\"a}ssler, Claus and Heurich, Marco and Brandl, Roland and Pretzsch, Hans and Seidl, Rupert and M{\"u}ller, J{\"o}rg}, title = {Biodiversity along temperate forest succession}, series = {Journal of Applied Ecology}, volume = {55}, journal = {Journal of Applied Ecology}, doi = {10.1111/1365-2664.13238}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-320632}, pages = {2756-2766}, year = {2018}, abstract = {1. The successional dynamics of forests—from canopy openings to regeneration, maturation, and decay—influence the amount and heterogeneity of resources available for forest-dwelling organisms. Conservation has largely focused only on selected stages of forest succession (e.g., late-seral stages). However, to develop comprehensive conservation strategies and to understand the impact of forest management on biodiversity, a quantitative understanding of how different trophic groups vary over the course of succession is needed. 2. We classified mixed mountain forests in Central Europe into nine successional stages using airborne LiDAR. We analysed α- and β-diversity of six trophic groups encompassing approximately 3,000 species from three kingdoms. We quantified the effect of successional stage on the number of species with and without controlling for species abundances and tested whether the data fit the more-individuals hypothesis or the habitat heterogeneity hypothesis. Furthermore, we analysed the similarity of assemblages along successional development. 3. The abundance of producers, first-order consumers, and saprotrophic species showed a U-shaped response to forest succession. The number of species of producer and consumer groups generally followed this U-shaped pattern. In contrast to our expectation, the number of saprotrophic species did not change along succession. When we controlled for the effect of abundance, the number of producer and saproxylic beetle species increased linearly with forest succession, whereas the U-shaped response of the number of consumer species persisted. The analysis of assemblages indicated a large contribution of succession-mediated β-diversity to regional γ-diversity. 4. Synthesis and applications. Depending on the species group, our data supported both the more-individuals hypothesis and the habitat heterogeneity hypothesis. Our results highlight the strong influence of forest succession on biodiversity and underline the importance of controlling for successional dynamics when assessing biodiversity change in response to external drivers such as climate change. The successional stages with highest diversity (early and late successional stages) are currently strongly underrepresented in the forests of Central Europe. We thus recommend that conservation strategies aim at a more balanced representation of all successional stages.}, language = {en} }