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Key role in ecosystem functioning of scavengers reliant on a single common species.

Inger R, Per E, Cox DT, Gaston KJ - Sci Rep (2016)

Bottom Line: The importance of species richness in maintaining ecosystem function in the field remains unclear.Recent studies however have suggested that in some systems functionality is maintained by a few abundant species.We find that, unlike those within largely unaltered environments, the scavenger community within our highly altered system is dominated by a single species, the Carrion crow, despite the presence of a number of other scavenging species.

View Article: PubMed Central - PubMed

Affiliation: Environment and Sustainability Institute, University of Exeter, Penryn, U.K.

ABSTRACT
The importance of species richness in maintaining ecosystem function in the field remains unclear. Recent studies however have suggested that in some systems functionality is maintained by a few abundant species. Here we determine this relationship by quantifying the species responsible for a key ecosystem role, carcass removal by scavengers. We find that, unlike those within largely unaltered environments, the scavenger community within our highly altered system is dominated by a single species, the Carrion crow, despite the presence of a number of other scavenging species. Furthermore, we find no relationship between abundance of crows and carcass removal. However, the overall activity of crows predicts carcass biomass removal rate in an asymptotic manner, suggesting that a relatively low level of abundance and scavenging activity is required to maintain this component of ecosystem function.

No MeSH data available.


Total time spent in different activities by different scavenger species.
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f1: Total time spent in different activities by different scavenger species.

Mentions: A total of 17 vertebrate species were recorded by camera traps at 63 (90%) of 70 deployed experimental rat carcasses. The total activity time was 113 hours, of which 94% was by Carrion crows (Corvus corone; Fig. 1). When only time spent eating the carrion was considered, 98% of the activity was by crows. Scavenger activity (eating or removing the carcass) was recorded at 49 carcasses (70%) by nine species. Vertebrate activity was recorded at 11 of our 12 study sites and scavenger activity was recorded at all 11 active sites. Seven species (Carrion crow, Common buzzard Buteo buteo, Domestic cat Felis catus, Domestic dog Canis familiaris, European magpie Pica pica, Herring Gull Larus argentatus & Wood mouse Apodemus sylvaticus) were recorded eating the carcass. Two species only ever removed the carcass (European badger Meles meles, Red fox Vulpes vulpes). One whole carcass was removed by a badger, and the remains of 9 carcasses were removed at night by foxes after originally being scavenged by crows. Crows were recorded both feeding on, and removing the remnants of a further five carcasses. Changes in carcass biomass differed considerably and significantly (R2GLMM(m) = 0.40, R2GLMM(c) = 0.50, F[1,98] = 99.27, p < 0.001) between experimental (scavengers having full access) (mean loss = 175.70 g, SD = 119.40) and encaged (which scavengers could not access) control groups (mean loss = 16.34 g, SD = 38.02). Apparent species richness was also significant (F[1,107] = 7.659, p = 0.007), with a general increase in biomass removed with increasing species richness, although the effect size in terms of the parameter estimate was considerably smaller than that of the experimental treatments (treatment β = 38.47 (SE = 4.48); apparent species richness β = 4.46 (SE = 1.61)).


Key role in ecosystem functioning of scavengers reliant on a single common species.

Inger R, Per E, Cox DT, Gaston KJ - Sci Rep (2016)

Total time spent in different activities by different scavenger species.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940730&req=5

f1: Total time spent in different activities by different scavenger species.
Mentions: A total of 17 vertebrate species were recorded by camera traps at 63 (90%) of 70 deployed experimental rat carcasses. The total activity time was 113 hours, of which 94% was by Carrion crows (Corvus corone; Fig. 1). When only time spent eating the carrion was considered, 98% of the activity was by crows. Scavenger activity (eating or removing the carcass) was recorded at 49 carcasses (70%) by nine species. Vertebrate activity was recorded at 11 of our 12 study sites and scavenger activity was recorded at all 11 active sites. Seven species (Carrion crow, Common buzzard Buteo buteo, Domestic cat Felis catus, Domestic dog Canis familiaris, European magpie Pica pica, Herring Gull Larus argentatus & Wood mouse Apodemus sylvaticus) were recorded eating the carcass. Two species only ever removed the carcass (European badger Meles meles, Red fox Vulpes vulpes). One whole carcass was removed by a badger, and the remains of 9 carcasses were removed at night by foxes after originally being scavenged by crows. Crows were recorded both feeding on, and removing the remnants of a further five carcasses. Changes in carcass biomass differed considerably and significantly (R2GLMM(m) = 0.40, R2GLMM(c) = 0.50, F[1,98] = 99.27, p < 0.001) between experimental (scavengers having full access) (mean loss = 175.70 g, SD = 119.40) and encaged (which scavengers could not access) control groups (mean loss = 16.34 g, SD = 38.02). Apparent species richness was also significant (F[1,107] = 7.659, p = 0.007), with a general increase in biomass removed with increasing species richness, although the effect size in terms of the parameter estimate was considerably smaller than that of the experimental treatments (treatment β = 38.47 (SE = 4.48); apparent species richness β = 4.46 (SE = 1.61)).

Bottom Line: The importance of species richness in maintaining ecosystem function in the field remains unclear.Recent studies however have suggested that in some systems functionality is maintained by a few abundant species.We find that, unlike those within largely unaltered environments, the scavenger community within our highly altered system is dominated by a single species, the Carrion crow, despite the presence of a number of other scavenging species.

View Article: PubMed Central - PubMed

Affiliation: Environment and Sustainability Institute, University of Exeter, Penryn, U.K.

ABSTRACT
The importance of species richness in maintaining ecosystem function in the field remains unclear. Recent studies however have suggested that in some systems functionality is maintained by a few abundant species. Here we determine this relationship by quantifying the species responsible for a key ecosystem role, carcass removal by scavengers. We find that, unlike those within largely unaltered environments, the scavenger community within our highly altered system is dominated by a single species, the Carrion crow, despite the presence of a number of other scavenging species. Furthermore, we find no relationship between abundance of crows and carcass removal. However, the overall activity of crows predicts carcass biomass removal rate in an asymptotic manner, suggesting that a relatively low level of abundance and scavenging activity is required to maintain this component of ecosystem function.

No MeSH data available.