TY  - JOUR
A1  - Roth, Nicolas
A1  - Hacker, Herrmann Heinrich
A1  - Heidrich, Lea
A1  - Friess, Nicolas
A1  - García-Barroas, Enrique
A1  - Habel, Jan Christian
A1  - Thorn, Simon
A1  - Müler, Jörg
T1  - Host specificity and species colouration mediate the regional decline of nocturnal moths in central European forests
JF  - Ecography
N2  - 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.
KW  - climate change
KW  - colour patterns
KW  - global change
KW  - Lepidoptera
KW  - macro moths
KW  - specialists
KW  - time series
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258731
VL  - 44
IS  - 6
ER  - 
TY  - JOUR
A1  - Maihoff, Fabienne
A1  - Friess, Nicolas
A1  - Hoiss, Bernhard
A1  - Schmid‐Egger, Christian
A1  - Kerner, Janika
A1  - Neumayer, Johann
A1  - Hopfenmüller, Sebastian
A1  - Bässler, Claus
A1  - Müller, Jörg
A1  - Classen, Alice
T1  - Smaller, more diverse and on the way to the top: Rapid community shifts of montane wild bees within an extraordinary hot decade
JF  - Diversity and Distributions
N2  - 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.
KW  - Alps
KW  - altitudinal gradient
KW  - body size
KW  - climate change
KW  - global warming
KW  - hymenoptera
KW  - pollinator
KW  - range shifts
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312126
VL  - 29
IS  - 2
ER  -