Vegetation and vertebrate abundance as drivers of bioturbation patterns along a climate gradient
Bioturbators shape their environment with considerable consequences for ecosystem processes. However, both the composition and the impact of bioturbator communities may change along climatic gradients. For burrowing animals, their abundance and composition depend on climatic and other abiotic com...
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|Bioturbators shape their environment with considerable consequences for ecosystem processes.
However, both the composition and the impact of bioturbator communities may
change along climatic gradients. For burrowing animals, their abundance and composition
depend on climatic and other abiotic components, with ants and mammals dominating in
arid and semiarid areas, and earthworms in humid areas. Moreover, the activity of burrowing
animals is often positively associated with vegetation cover (biotic component). These
observations highlight the need to understand the relative contributions of abiotic and biotic
components in bioturbation in order to predict soil-shaping processes along broad climatic
gradients. In this study, we estimated the activity of animal bioturbation by counting the density
of holes and the quantity of bioturbation based on the volume of soil excavated by bioturbators
along a gradient ranging from arid to humid in Chile. We distinguished between
invertebrates and vertebrates. Overall, hole density (no/ 100 m2) decreased from arid (raw
mean and standard deviation for invertebrates: 14 ± 7.8, vertebrates: 2.8 ± 2.9) to humid
(invertebrates: 2.8 ± 3.1, vertebrates: 2.2 ± 2.1) environments. However, excavated soil volume
did not follow the same clear geographic trend and was 300-fold larger for vertebrates
than for invertebrates. The relationship between bioturbating invertebrates and vegetation
cover was consistently negative whereas for vertebrates both, positive and negative relationships
were determined along the gradient. Our study demonstrates complex relationships
between climate, vegetation and the contribution of bioturbating invertebrates and
vertebrates, which will be reflected in their impact on ecosystem functions.
|Gefördert durch den Open-Access-Publikationsfonds der UB Marburg.