Ecosystem functioning in relation to species identity, density, and biomass in two tunneller dung beetles

Functional trait-based approaches are increasingly adopted to understand and project ecological responses to environmental change; however, most assume trait expression is constant between conspecifics irrespective of context. Using two species of benthic invertebrate (brittlestars Amphiura filiformis and Amphiura chiajei ), we demonstrate that trait expression at individual and community levels differs with biotic and abiotic context. We use PERMANOVA to test the effect of species identity, density and local environmental history on individual (righting and burrowing) and community (particle reworking and burrow ventilation) trait expression, as well as associated effects on ecosystem functioning (sediment nutrient release). Trait expression differs with context, with repercussions for the faunal mediation of ecosystem processes; we find increased rates of righting and burial behaviour and greater particle reworking with increasing density that are reflected in nutrient generation. However, the magnitude of effects differed within and between species, arising from site-specific environmental and morphological differences. Our results indicate that traits and processes influencing change in ecosystem functioning are products of both prevailing and historic conditions that cannot be constrained within typologies. Trait-based study must incorporate context-dependent variation, including intraspecific differences from individual to ecosystem scales, to avoid jeopardizing projections of ecosystem functioning and service delivery.

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Drivers of understorey biomass – tree species identity is more important than richness in a young forest

Journal of Plant Ecology ◽

10.1093/jpe/rtab004 ◽

2021 ◽

Author(s):

Markus S Germany ◽

Helge Bruelheide ◽

Alexandra Erfmeier

Keyword(s):

Species Richness ◽

Tree Species ◽

Ecosystem Functioning ◽

Temporal Dynamics ◽

Light Transmittance ◽

Productivity Change ◽

Species Identity ◽

Tree Species Richness ◽

Young Forest ◽

Species Richness Gradient

Abstract Aims Positive biodiversity ecosystem functioning relationships have been widely reported, predominately from grassland ecosystems. However, this does not necessarily have to apply accordingly in more complex situations such as in forests across different vertical strata. For instance, overstorey tree species richness has been shown to be associated with a lower understorey productivity. Whether or not tree species richness effects add to understorey productivity by increasing (i.e. due to habitat heterogeneity) or reducing resource availability (i.e. through increasing competition) and whether understorey productivity is indeed being governed more strongly by tree species identity are likely to change over time. Moreover, studies also suggested that richness-productivity relationships change with the environmental context. Using an experimental forest plantation with manipulated tree species richness, this study examined these temporal and environmental dynamics across strata. Methods In the context of the Biodiversity-Ecosystem Functioning project in subtropical China (BEF-China), we made use of understorey biomass samples repeatedly collected over a time period of three years along a tree species richness gradient. The effects of tree species richness, tree species identities and time were studied across different environmental treatments for their impact on understorey biomass. Important Findings While we found significant and consistent tree layer identity effects on understorey biomass, no such effect was encountered for tree species richness. Our results also indicate that among structural layers in forests, there might not be a single, generalizable overstorey species richness- understorey productivity relationship, and that the extent as to which overstorey-related environmental factors such as light transmittance contribute to understorey productivity change with time. Overall, we demonstrate that temporal dynamics should be considered when studying relationship among structural layers in forests.

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Linking Biodiversity, the Environment and Ecosystem Functioning: Ecological Functions of Dung Beetles Along a Tropical Elevational Gradient

Ecosystems ◽

10.1007/s10021-017-0216-y ◽

2018 ◽

Vol 21 (6) ◽

pp. 1244-1254 ◽

Cited By ~ 8

Author(s):

Cássio Alencar Nunes ◽

Rodrigo Fagundes Braga ◽

Fernando de Moura Resende ◽

Frederico de Siqueira Neves ◽

José Eugênio Cortes Figueira ◽

...

Keyword(s):

Ecosystem Functioning ◽

Elevational Gradient ◽

Dung Beetles ◽

Ecological Functions

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Dung beetle–mammal associations: methods, research trends and future directions

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.2002 ◽

2019 ◽

Vol 286 (1897) ◽

pp. 20182002 ◽

Cited By ~ 13

Author(s):

Elizabeth H. Raine ◽

Eleanor M. Slade

Keyword(s):

Ecosystem Functioning ◽

Environmental Gradients ◽

Association Studies ◽

Terrestrial Ecosystems ◽

Dung Beetle ◽

Field Studies ◽

Dung Beetles ◽

Mammal Species ◽

Wide Range ◽

Species Richness And Abundance

Dung beetles are increasingly used as a study taxon—both as bioindicators of environmental change, and as a model system for exploring ecosystem functioning. The advantages of this focal taxon approach are many; dung beetles are abundant in a wide range of terrestrial ecosystems, speciose, straightforward to sample, respond to environmental gradients and can be easily manipulated to explore species-functioning relationships. However, there remain large gaps in our understanding of the relationship between dung beetles and the mammals they rely on for dung. Here we review the literature, showing that despite an increase in the study of dung beetles linked to ecosystem functioning and to habitat and land use change, there has been little research into their associations with mammals. We summarize the methods and findings from dung beetle–mammal association studies to date, revealing that although empirical field studies of dung beetles rarely include mammal data, those that do, indicate mammal species presence and composition has a large impact on dung beetle species richness and abundance. We then review the methods used to carry out diet preference and ecosystem functioning studies, finding that despite the assumption that dung beetles are generalist feeders, there are few quantitative studies that directly address this. Together this suggests that conclusions about the effects of habitat change on dung beetles are based on incomplete knowledge. We provide recommendations for future work to identify the importance of considering mammal data for dung beetle distributions, composition and their contributions to ecosystem functioning; a critical step if dung beetles are to be used as a reliable bioindicator taxon.

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