The joint contributions of environmental filtering and spatial processes
to macroinvertebrate metacommunity dynamics in the alpine stream
environment of Baima Snow Mountain, Southwest China
Abstract
As a rapidly growing field of community ecology, the study of
meta-communities provides an effective framework to unravel community
assembly mechanisms by focusing on the relative contributions of
environmental screening and spatial processes. While macroinvertebrates
have been extensively investigated in many river ecosystems,
meta-community ecology perspectives in high mountain stream networks are
very limited. In this study, we assessed the role of ecological
determinants and temporal dynamics in the macroinvertebrate
meta-community assembly of an alpine stream situated in a dry-hot valley
of Baima Snow Mountain, Northwest Yunnan. Our results show significant
differences in the macroinvertebrate community composition across time
periods. Spatial structuring and environmental filtering jointly drive
the configuration of macroinvertebrate meta-community, with relative
contributions to the variance in community composition varying over
time. Redundancy Analysis (RDA) and variation partitioning indicate that
environmental variables are the most important predictors of community
organization in most scenarios, whereas spatial determinants also play a
significant role. Moreover, the explanatory power, identity, and the
relative significance of ecological indicators change over time.
Particularly, in the years 2018 and 2019, stronger environmental
filtering was found shaping community assembly, suggesting that
deterministic mechanisms predominated in driving community dynamics in
such a specific environment of the stream. However, spatial factors had
a stronger predictive power on meta-community structures in 2017,
implying conspicuous dispersal mechanisms which may be owing to
increased connectivity amongst locations. Thereby, we inferred that the
stream macroinvertebrate metacommunity composition can be regulated by
the interaction of both spatial processes and environmental filtering,
with relative contributions varying over time. Based on these findings,
we suggest that community ecology studies in aquatic systems should be
designed beyond single snapshot investigations.