Tiede, Y.; Schlautmann, J.; Donoso, D.A.; Wallis, C.I.B.; Bendix, J.; Brandl, R. & Farwig, N. (2017): <b> Ants as indicators of environmental change and ecosystem processes</b>. <i>Ecological Indicators</i> <b>83</b>, 527–537.
Resource Description
Title:
Ants as indicators of environmental change and ecosystem processes
email:
bendix <at> staff.uni-marburg.de
Deutschhausstraße 12
Room No. 02 A 48
35032 Marburg
Faculty of Geography
Germany
Individual:
Roland Brandl
Contact:
email:
webmaster <at> lcrs.de
Individual:
Nina Farwig
Contact:
email:
webmaster <at> lcrs.de
Abstract:
Environmental stressors and changes in land use have led to rapid and dramatic species losses. As such,<br/>
we need effective monitoring programs that alert us not only to biodiversity losses, but also to functional<br/>
changes in species assemblages and associated ecosystem processes. Ants are important components<br/>
of terrestrial food webs and a key group in food web interactions and numerous ecosystem processes. Their sensitive and <br/>
rapid response to environmental changes suggests that they are a suitable indicator group for the monitoring of abiotic, <br/>
biotic, and functional changes. We tested the suitability of the incidence (i.e. the sum of all species occurrences <br/>
at 30 baits), species richness, and functional richness of ants as indicators of ecological responses to environmental change, forest degradation, and of the<br/>
ecosystem process predation on herbivorous arthropods. We sampled data along an elevational gradient<br/>
(1000–3000 m a.s.l.) and across seasons (wetter and drier period) in a montane rainforest in south-<br/>
ern Ecuador. The incidence of ants declined with increasing elevation but did not change with forest<br/>
degradation. <br/>
Ant incidence was higher during the drier season. Species richness was highly correlated<br/>
with incidence and showed comparable results. Functional richness also declined with increasing ele-<br/>
vation and did not change with forest degradation. However, a null-model comparison revealed that<br/>
the functional richness pattern did not differ from a pattern expected for ant assemblages with ran-<br/>
domly distributed sets of traits across species. Predation on arti?cial caterpillars decreased along the<br/>
elevational gradient; the pattern was not driven by elevation itself, but by ant incidence (or inter-<br/>
changeable by ant richness), which positively affected predation. In spite of lower ant incidence (or<br/>
ant richness), predation was higher during the wetter season and did not change with forest degrada-<br/>
tion and ant functional richness. We used path analysis to disentangle the causal relationships of the<br/>
environmental factors temperature (with elevation as a proxy), season, and habitat degradation with<br/>
the incidence and functional richness of ants, and their consequences for predation. Our results would<br/>
suggest that the forecasted global warming might support more active and species-rich ant assem-<br/>
blages, which in turn would mediate increased predation on herbivorous arthropods. However, this<br/>
prediction should be made with reservation, as it assumes that the dispersal of ants keeps pace with<br/>
the climatic changes as well as a one-dimensional relationship between ants and predation within a<br/>
food-web that comprises species interactions of much higher complexity. Our results also suggested<br/>
that degraded forests in our study area might provide suitable habitat for epigaeic, ground-dwelling ant<br/>
assemblages that do not differ in incidence, species richness, functional richness, composition, or predation <br/>
on arthropods from assemblages of primary forests. Most importantly, our results suggest that<br/>
the occurrence and activity of ants are important drivers of ecosystem processes and that changes in the<br/>
incidence and richness of ants can be used as effective indicators of responses to temperature changes<br/>
and of predation within mega-diverse forest ecosystems
Keywords:
| southern Ecuador | Functioanl Monitoring | Ants |
Literature type specific fields:
ARTICLE
Journal:
Ecological Indicators
Volume:
83
Page Range:
527–537
Metadata Provider:
Individual:
Jörg Bendix
Contact:
email:
bendix <at> staff.uni-marburg.de
Deutschhausstraße 12
Room No. 02 A 48
35032 Marburg
Faculty of Geography
Germany
