@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{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{KortmannRothBuseetal.2022, author = {Kortmann, Mareike and Roth, Nicolas and Buse, J{\"o}rn and Hilszczański, Jacek and Jaworski, Tomasz and Morini{\`e}re, J{\´e}r{\^o}me and Seidl, Rupert and Thorn, Simon and M{\"u}ller, J{\"o}rg C.}, title = {Arthropod dark taxa provide new insights into diversity responses to bark beetle infestations}, series = {Ecological Applications}, volume = {32}, journal = {Ecological Applications}, number = {2}, doi = {10.1002/eap.2516}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-276392}, year = {2022}, abstract = {Natural disturbances are increasing around the globe, also impacting protected areas. Although previous studies have indicated that natural disturbances result in mainly positive effects on biodiversity, these analyses mostly focused on a few well established taxonomic groups, and thus uncertainty remains regarding the comprehensive impact of natural disturbances on biodiversity. Using Malaise traps and meta-barcoding, we studied a broad range of arthropod taxa, including dark and cryptic taxa, along a gradient of bark beetle disturbance severities in five European national parks. We identified order-level community thresholds of disturbance severity and classified barcode index numbers (BINs; a cluster system for DNA sequences, where each cluster corresponds to a species) as negative or positive disturbance indicators. Negative indicator BINs decreased above thresholds of low to medium disturbance severity (20\%-30\% of trees killed), whereas positive indicator BINs benefited from high disturbance severity (76\%-98\%). BINs allocated to a species name contained nearly as many positive as negative disturbance indicators, but dark and cryptic taxa, particularly Diptera and Hymenoptera in our data, contained higher numbers of negative disturbance indicator BINs. Analyses of changes in the richness of BINs showed variable responses of arthropods to disturbance severity at lower taxonomic levels, whereas no significant signal was detected at the order level due to the compensatory responses of the underlying taxa. We conclude that the analyses of dark taxa can offer new insights into biodiversity responses to disturbances. Our results suggest considerable potential for forest management to foster arthropod diversity, for example by maintaining both closed-canopy forests (>70\% cover) and open forests (<30\% cover) on the landscape.}, language = {en} } @article{BaeHeidrichLevicketal.2020, author = {Bae, Soyeon and Heidrich, Lea and Levick, Shaun R. and Gossner, Martin M. and Seibold, Sebastian and Weisser, Wolfgang W. and Magdon, Paul and Serebryanyk, Alla and B{\"a}ssler, Claus and Sch{\"a}fer, Deborah and Schulze, Ernst-Detlef and Doerfler, Inken and M{\"u}ller, J{\"o}rg and Jung, Kirsten and Heurich, Marco and Fischer, Markus and Roth, Nicolas and Schall, Peter and Boch, Steffen and W{\"o}llauer, Stephan and Renner, Swen C. and M{\"u}ller, J{\"o}rg}, title = {Dispersal ability, trophic position and body size mediate species turnover processes: Insights from a multi-taxa and multi-scale approach}, series = {Diversity and Distribution}, volume = {27}, journal = {Diversity and Distribution}, number = {3}, doi = {10.1111/ddi.13204}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236117}, pages = {439-453}, year = {2020}, abstract = {Aim: Despite increasing interest in β-diversity, that is the spatial and temporal turnover of species, the mechanisms underlying species turnover at different spatial scales are not fully understood, although they likely differ among different functional groups. We investigated the relative importance of dispersal limitations and the environmental filtering caused by vegetation for local, multi-taxa forest communities differing in their dispersal ability, trophic position and body size. Location: Temperate forests in five regions across Germany. Methods: In the inter-region analysis, the independent and shared effects of the regional spatial structure (regional species pool), landscape spatial structure (dispersal limitation) and environmental factors on species turnover were quantified with a 1-ha grain across 11 functional groups in up to 495 plots by variation partitioning. In the intra-region analysis, the relative importance of three environmental factors related to vegetation (herb and tree layer composition and forest physiognomy) and spatial structure for species turnover was determined. Results: In the inter-region analysis, over half of the explained variation in community composition (23\% of the total explained 35\%) was explained by the shared effects of several factors, indicative of spatially structured environmental filtering. Among the independent effects, environmental factors were the strongest on average over 11 groups, but the importance of landscape spatial structure increased for less dispersive functional groups. In the intra-region analysis, the independent effect of plant species composition had a stronger influence on species turnover than forest physiognomy, but the relative importance of the latter increased with increasing trophic position and body size. Main conclusions: Our study revealed that the mechanisms structuring assemblage composition are associated with the traits of functional groups. Hence, conservation frameworks targeting biodiversity of multiple groups should cover both environmental and biogeographical gradients. Within regions, forest management can enhance β-diversity particularly by diversifying tree species composition and forest physiognomy.}, language = {en} } @article{RothDoerflerBaessleretal.2019, author = {Roth, Nicolas and Doerfler, Inken and B{\"a}ssler, Claus and Blaschke, Markus and Bussler, Heinz and Gossner, Martin M. and Heideroth, Antje and Thorn, Simon and Weisser, Wolfgang W. and M{\"u}ller, J{\"o}rg}, title = {Decadal effects of landscape-wide enrichment of dead wood on saproxylic organisms in beech forests of different historic management intensity}, series = {Diversity and Distributions}, volume = {25}, journal = {Diversity and Distributions}, number = {3}, doi = {10.1111/ddi.12870}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227061}, pages = {430-441}, year = {2019}, abstract = {Aim: European temperate forests have lost dead wood and the associated biodiversity owing to intensive management over centuries. Nowadays, some of these forests are being restored by enrichment with dead wood, but mostly only at stand scales. Here, we investigated effects of a seminal dead-wood enrichment strategy on saproxylic organisms at the landscape scale. Location: Temperate European beech forest in southern Germany. Methods: In a before-after control-impact design, we compared assemblages and gamma diversities of saproxylic organisms in strictly protected old-growth forest areas (reserves) and historically moderately and intensively managed forest areas before and a decade after starting a landscape-wide strategy of dead-wood enrichment. Results: Before enrichment with dead wood, the gamma diversity of saproxylic organisms in historically intensively managed forest stands was significantly lower than in reserves and historically moderately managed forest stands; this difference disappeared after 10 years of dead-wood enrichment. The species composition of beetles in forest stands of the three historical management intensities differed before the enrichment strategy, but a decade thereafter, the species compositions of previously intensively logged and forest reserve plots were similar. However, the differences in fungal species composition between historical management categories before and after 10 years of enrichment persisted. Main conclusions: Our results demonstrate that intentional enrichment of dead wood at the landscape scale is a powerful tool for rapidly restoring saproxylic beetle communities and for restoring wood-inhabiting fungal communities, which need longer than a decade for complete restoration. We propose that a strategy of area-wide active restoration combined with some permanent strict refuges is a promising means of promoting the biodiversity of age-long intensively managed Central European beech forests.}, language = {en} } @phdthesis{Roth2021, author = {Roth, Nicolas M{\´e}riadec Max Andr{\´e}}, title = {Temporal development of communities with a focus on insects, in time series of one to four decades}, doi = {10.25972/OPUS-23549}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235499}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Changes and development are fundamental principles in biocenoses and can affect a multitude of ecological processes. In insect communities phenological and density changes, changes in species richness and community composition, as well as interactions between those changes, are the most important macro processes. However, climate change and other factors like habitat degradation and loss alter these processes leading to shifts and general biodiversity declines. Even though knowledge about insect decline in central Europe increased during the last decades, there are significant knowledge gaps about the development of insect communities in certain habitats and taxa. For example, insect communities in small lentic as well as in forested habitats are under-sampled and reported to be less endangered than communities in other habitats. Furthermore, the changes within habitats and taxa are additionally influenced by certain traits, like host or feeding specialization. To disentangle these influences and to increase the knowledge about the general long-term development of insect communities, comprehensive long-term monitoring studies are needed. In addition, long-term effects of conservation strategies should also be evaluated on large time scales in order to be able to decide on a scientific base which strategies are effective in promoting possibly declining taxa. Hence, this thesis also tackles the effects of an integrative conservation strategy on wood dependent beetle and fungi, beside the development of water beetle and macro moth communities over multiple decades. In Chapter 2 I present a study on the development of water beetle communities (Dytiscidae, Haliplidae, Noteridae) in 33 water bodies in Southern Germany from 1991 to 2018. Time-standardized capture per waterbody was used during three periods: between 1991 and 1995, 2007 and 2008, and 2017 and 2018. Results showed annual declines in both species number (ca. -1\%) and abundance (ca. -2\%). In addition, community composition shifted over time in part due to changing pH values. Hence, the recorded changes during the 28-year study period partly reflect natural succession processes. However, since also moor-related beetle species decreased significantly, it is likely that water beetles in southern Germany are also threatened by non-successional factors, including desiccation, increased nitrogen input and/or mineralization, as well as the loss of specific habitats. The results suggest, that in small to midsize lentic waterbodies, current development should aim for constant creation of new water bodies and protection of moor waterbodies in order to protect water beetle communities on a landscape scale. In Chapter 3 I present an analysis of the development of nocturnal macro moth species richness, abundance and biomass over four decades in forests of southern Germany. Two local scale data sets featuring a coppiced oak forest as well as an oak high forest were analysed separately from a regional data set representing all forest types in the temperate zone of Central Europe. At the regional scale species richness, abundance and biomass showed annual declines of ca. 1 \%, 1.3 \% and 1.4 \%, respectively. These declines were more pronounced in plant host specialists and in dark coloured species. In contrast, species richness increased by ca. 1.5 \% annually in the coppiced forest, while no significant trends were found in the high forest. In contrast to past assumptions, insect decline apparently affects also hyper diverse insect groups in forests. Since host specialists and dark coloured species were affected more heavily by the decline than other groups, habitat loss and climate change seem to be potential drivers of the observed trends. However, the positive development of species richness in the coppiced oak forest indicates that maintaining complex and diverse forest ecosystems through active management might compensate for negative trends in biodiversity. Chapter 4 features a study specifically aiming to investigate the long-term effect of deadwood enrichment as an integrative conservation strategy on saproxylic beetles and fungi in a central European beech forest at a landscape scale. A before-after control-impact design, was used to compare assemblages and gamma diversities of saproxylic organisms (beetles and fungi) in strictly protected old-growth forest areas (reserves) and previously moderately and intensively managed forest areas. Forests were sampled one year before and a decade after starting a landscape-wide strategy of dead-wood enrichment. Ten years after the start of the dead-wood enrichment, neither gamma diversities of saproxylic organisms nor species composition of beetles did reflect the previous management types anymore. However, fungal species composition still mirrored the previous management gradient. The results demonstrated that intentional enrichment of dead wood at the landscape scale can effectively restore communities of saproxylic organisms and may thus be a suitable strategy in addition to permanent strict reserves in order to protect wood dependent organisms in Europe. In this thesis I showed, that in contrast to what was assumed and partly reported so far, also water beetles in lentic water bodies and macro moths in forests decreased in species richness, abundance and biomass during the last three to four decades. In line with earlier studies, especially dark coloured species and specialists decreased more than light-coloured species and generalists. The reasons for these declines could partly be attributed to natural processes and pollution and possibly to climate change. However, further studies, especially experimental ones, will be needed to achieve a better understanding of the reasons for insect decline. Furthermore, analyses of time series data should be interpreted cautiously especially if the number of sampling years is smaller than ten years. In addition, validation techniques such as left- and right- censoring and cross validation should be used in order to proof the robustness of the analyses. However, the lack of knowledge, we are still facing today, should not prevent scientists and practitioners from applying conservation measures. In order to prove the effectiveness of such measures, long-term monitoring is crucial. Such control of success is essential for evidence based and thus adapted conservation strategies of threatened organisms.}, subject = {climate change}, language = {en} } @article{RothZoderZamanetal.2020, author = {Roth, Nicolas and Zoder, Sebastian and Zaman, Assad Ali and Thorn, Simon and Schmidl, J{\"u}rgen}, title = {Long-term monitoring reveals decreasing water beetle diversity, loss of specialists and community shifts over the past 28 years}, series = {Insect Conservation and Diversity}, volume = {13}, journal = {Insect Conservation and Diversity}, number = {2}, doi = {10.1111/icad.12411}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214905}, pages = {140 -- 150}, year = {2020}, abstract = {Lentic freshwater organisms are influenced by a multitude of factors, including geomorphology, hydrology, anthropogenic impacts and climate change. Organisms that depend on patchy resources such as water beetles may also be sensitive to anthropogenic habitat degradation, like pollution, eutrophication, water level or management alteration. To assess composition and ecological trends in the water beetle communities of Central Europe, we sampled water beetles (Dytiscidae, Haliplidae, Noteridae) in 33 water bodies in Southern Germany from 1991 to 2018. We used manual, time-standardised capture during three periods: between 1991 and 1995, 2007 and 2008, and 2017 and 2018. During the 28-year survey period, we captured a total of 81 species. We found annual declines in both species number (ca -1\%) and abundance (ca -2\%). Also, community composition showed significant changes over time. The significant impact of pH on the community composition suggests that the recorded changes through time partly reflect natural succession processes. However, a pronounced decline of beetle species belonging to the moor-related beetle associations indicated that Central European water beetles are also threatened by non-successional factors, including desiccation, increased nitrogen input and/or mineralisation, and the loss of specific habitats. This trend to physiographical homogenisation resulted in corresponding community composition shifts. To effectively protect endangered species, conservation strategies need to be aimed at regularly creating new water bodies with mineralic bottom substratum, and maintenance of moor water bodies that represent late successional stages.}, language = {en} }