TY  - JOUR
A1  - Roth, Nicolas
A1  - Zoder, Sebastian
A1  - Zaman, Assad Ali
A1  - Thorn, Simon
A1  - Schmidl, Jürgen
T1  - Long‐term monitoring reveals decreasing water beetle diversity, loss of specialists and community shifts over the past 28 years
JF  - Insect Conservation and Diversity
N2  - 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.
KW  - biodiversity
KW  - lentic inland water bodies
KW  - long‐term monitoring
KW  - time series
KW  - water beetles
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-214905
VL  - 13
IS  - 2
SP  - 140
EP  - 150
ER  - 
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  -