Human perturbations reduce dung beetle diversity and dung removal ecosystem function

Limited thermal plasticity may constrain ecosystem function in a basally heat tolerant tropical telecoprid dung beetle, Allogymnopleurus thalassinus (Klug, 1855)

Scientific Reports ◽

10.1038/s41598-021-01478-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Honest Machekano ◽

Chipo Zidana ◽

Nonofo Gotcha ◽

Casper Nyamukondiwa

Keyword(s):

Climate Change ◽

Ecosystem Function ◽

Heat Tolerance ◽

Natural Capital ◽

Variable Temperature ◽

Dung Beetle ◽

Tropical Species ◽

Arid Environments ◽

Trade Off ◽

Thermal Plasticity

AbstractTropical organisms are more vulnerable to climate change and associated heat stress as they live close to their upper thermal limits (UTLs). UTLs do not only vary little across tropical species according to the basal versus plasticity ‘trade-off’ theory but may also be further constrained by low genetic variation. We tested this hypothesis, and its effects on ecosystem function using a diurnally active dung rolling beetle (telecoprid), Allogymnopleurus thalassinus (Klug, 1855) that inhabits arid environments. Specifically, (i) we tested basal heat tolerance (critical thermal maxima [CTmax] and heat knockdown time [HKDT]), and (ii) ecological functioning (dung removal) efficiency following dynamic chronic acclimation temperatures of variable high (VT-H) (28–45 °C) and variable low (VT-L) (28–16 °C). Results showed that A. thalassinus had extremely high basal heat tolerance (> 50 °C CTmax and high HKDT). Effects of acclimation were significant for heat tolerance, significantly increasing and reducing CTmax values for variable temperature high and variable temperature low respectively. Similarly, effects of acclimation on HKDT were significant, with variable temperature high significantly increasing HKDT, while variable temperature low reduced HKDT. Effects of acclimation on ecological traits showed that beetles acclimated to variable high temperatures were ecologically more efficient in their ecosystem function (dung removal) compared to those acclimated at variable low temperatures. Allogymnopleurus thalassinus nevertheless, had low acclimation response ratios, signifying limited scope for complete plasticity for UTLs tested here. This result supports the ‘trade-off’ theory, and that observed limited plasticity may unlikely buffer A. thalassinus against effects of climate change, and by extension, albeit with caveats to other tropical ecological service providing insect species. This work provides insights on the survival mechanisms of tropical species against heat and provides a framework for the conservation of these natural capital species that inhabit arid environments under rapidly changing environmental climate.

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Experimental evidence for the effects of dung beetle functional group richness and composition on ecosystem function in a tropical forest

Journal of Animal Ecology ◽

10.1111/j.1365-2656.2007.01296.x ◽

2007 ◽

Vol 76 (6) ◽

pp. 1094-1104 ◽

Cited By ~ 168

Author(s):

ELEANOR M. SLADE ◽

DARREN J. MANN ◽

JEROME F. VILLANUEVA ◽

OWEN T. LEWIS

Keyword(s):

Tropical Forest ◽

Experimental Evidence ◽

Ecosystem Function ◽

Functional Group ◽

Dung Beetle

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Dominance determines fish community biomass in a temperate seagrass ecosystem

10.32942/osf.io/cqjvu ◽

2019 ◽

Author(s):

Aaron Matthius Eger ◽

Rebecca J. Best ◽

Julia Kathleen Baum

Keyword(s):

Species Richness ◽

Ecosystem Function ◽

Fish Community ◽

Prey Capture ◽

Fish Communities ◽

Functional Trait ◽

Ecosystem Functions ◽

Community Biomass ◽

Ecosystem Valuation ◽

Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

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