Effects of management on aquatic tree-hole communities in temperate forests are mediated by detritus amount and water chemistry.
Arthropod communities in water-filled tree holes may be sensitive to impacts of forest management, for example via changes in environmental conditions such as resource input. We hypothesized that increasing forest management intensity (ForMI) negatively affects arthropod abundance and richness and shifts community composition and trophic structure of tree hole communities. We predicted that this shift is caused by reduced habitat and resource availability at the forest stand scale as well as reduced tree hole size, detritus amount and changed water chemistry at the tree holes scale. We mapped 910 water-filled tree holes in two regions in Germany and studied 199 tree hole inhabiting arthropod communities. We found that increasing ForMI indeed significantly reduced arthropod abundance and richness in water-filled tree holes. The most important indirect effects of management intensity on tree hole community structure were the reduced amounts of detritus for the tree hole inhabiting organisms and changed water chemistry at the tree hole scale, both of which seem to act as a habitat filter. Although habitat availability at the forest stand scale decreased with increasing management intensity, this unexpectedly increased local arthropod abundance in individual tree holes. However, regional species richness in tree holes significantly decreased with increasing management intensity, most likely due to decreased habitat diversity. We did not find that the management-driven increase in plant diversity at the forest stand scale affected communities of individual tree holes, for example via resource availability for adults. Our results suggest that management of temperate forests has to target a number of factors at different scales to conserve diverse arthropod communities in water-filled tree holes.
Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Center for Food and Life Sciences Weihenstephan, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising-Weihenstephan, Germany.|Institute of Ecology, Friedrich-Schiller-University, 07745, Jena, Germany.
Martin M
MM
Gossner
Institute of Ecology, Friedrich-Schiller-University, 07745, Jena, Germany.
Peggy
P
Lade
Institute of Ecology, Friedrich-Schiller-University, 07745, Jena, Germany.
Anja
A
Rohland
Institute of Ecology, Friedrich-Schiller-University, 07745, Jena, Germany.
Nora
N
Sichardt
Chair of Silviculture, Institute of Forest Sciences, Freiburg University, 79085, Freiburg, Germany.
Tiemo
T
Kahl
Chair of Silviculture, Institute of Forest Sciences, Freiburg University, 79085, Freiburg, Germany.
Jürgen
J
Bauhus
Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Center for Food and Life Sciences Weihenstephan, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising-Weihenstephan, Germany.|Institute of Ecology, Friedrich-Schiller-University, 07745, Jena, Germany.
Wolfgang W
WW
Weisser
Department of Ecology and Evolution, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria.|Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195, Berlin, Germany.
Jana S
JS
Petermann
D000818:Animals; D059001:Aquatic Organisms / Q000502:physiology; D044822:Biodiversity; D003247:Conservation of Natural Resources; D016468:Forestry; D065928:Forests; D005618:Fresh Water; D005858:Germany; D007313:Insecta / Q000502:physiology*; D014197:Trees; D014867:Water / Q000737:chemistry*
D014867:Water
aquatic larvae; biodiversity exploratories; community composition; dispersal; diversity; habitat filter; land-use intensity; metacommunity; phytotelmata; species sorting