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Flow directionality, mountain barriers and functional traits determine diatom metacommunity structuring of high mountain streams.

Dong X, Li B, He F, Gu Y, Sun M, Zhang H, Tan L, Xiao W, Liu S, Cai Q - Sci Rep (2016)

Bottom Line: Our results indicated that both environmental filtering and dispersal processes influenced metacommunity structuring, with dispersal contributing more than environmental processes.Our results highlighted that directional processes had prevailing effects on metacommunity structuring in high mountain streams.Flow directionality, mountain barriers and ecological guilds contributed to a better understanding of the roles that mountains played in structuring metacommunity.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.

ABSTRACT
Stream metacommunities are structured by a combination of local (environmental filtering) and regional (dispersal) processes. The unique characters of high mountain streams could potentially determine metacommunity structuring, which is currently poorly understood. Aiming at understanding how these characters influenced metacommunity structuring, we explored the relative importance of local environmental conditions and various dispersal processes, including through geographical (overland), topographical (across mountain barriers) and network (along flow direction) pathways in shaping benthic diatom communities. From a trait perspective, diatoms were categorized into high-profile, low-profile and motile guild to examine the roles of functional traits. Our results indicated that both environmental filtering and dispersal processes influenced metacommunity structuring, with dispersal contributing more than environmental processes. Among the three pathways, stream corridors were primary pathway. Deconstructive analysis suggested different responses to environmental and spatial factors for each of three ecological guilds. However, regardless of traits, dispersal among streams was limited by mountain barriers, while dispersal along stream was promoted by rushing flow in high mountain stream. Our results highlighted that directional processes had prevailing effects on metacommunity structuring in high mountain streams. Flow directionality, mountain barriers and ecological guilds contributed to a better understanding of the roles that mountains played in structuring metacommunity.

No MeSH data available.


Related in: MedlinePlus

Venn-diagrams showing the results of variation partitioning performed on (a) Environmental model (Env) and Geographical model (PCNMG), (b) Environmental model (Env) and Topographic model (PCNMT), and (c) Environmental model (Env) and Directional spatial model (AEM) for benthic diatom metacommuntiy in the study area. Variation explained uniquely and jointly, and the unexplained fractions were shown as the number in each part of the figures (total variation = 1). The significance of each testable fraction was expressed as ■P < 0.1, *P < 0.05, **P < 0.01, ***P < 0.001.
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f3: Venn-diagrams showing the results of variation partitioning performed on (a) Environmental model (Env) and Geographical model (PCNMG), (b) Environmental model (Env) and Topographic model (PCNMT), and (c) Environmental model (Env) and Directional spatial model (AEM) for benthic diatom metacommuntiy in the study area. Variation explained uniquely and jointly, and the unexplained fractions were shown as the number in each part of the figures (total variation = 1). The significance of each testable fraction was expressed as ■P < 0.1, *P < 0.05, **P < 0.01, ***P < 0.001.

Mentions: Variation partitioning was firstly performed on environmental variables (Env) and geographical spatial variables (PCNMG) for diatom communities. Both sets of variables were significant and could explain 54% variation of diatom communities (Fig. 3a). The variation purely explained by Env and PCNMG was 22% and 12% respectively, while the shared fraction was 21% (Fig. 3a). Env and topographic spatial variables (PCNMT) explained 51% of the community variation. Env alone explained much more than PCNMT (31% and 9%), while both explained 11% community variation (Fig. 3b). Directional spatial variables (AEM) had a unique contribution of 22% to metacommunity structuring, and the total explained variation increased to 65%. Furthermore, the unique faction of Env (3%) turned to be marginally significant (Fig. 3c).


Flow directionality, mountain barriers and functional traits determine diatom metacommunity structuring of high mountain streams.

Dong X, Li B, He F, Gu Y, Sun M, Zhang H, Tan L, Xiao W, Liu S, Cai Q - Sci Rep (2016)

Venn-diagrams showing the results of variation partitioning performed on (a) Environmental model (Env) and Geographical model (PCNMG), (b) Environmental model (Env) and Topographic model (PCNMT), and (c) Environmental model (Env) and Directional spatial model (AEM) for benthic diatom metacommuntiy in the study area. Variation explained uniquely and jointly, and the unexplained fractions were shown as the number in each part of the figures (total variation = 1). The significance of each testable fraction was expressed as ■P < 0.1, *P < 0.05, **P < 0.01, ***P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835781&req=5

f3: Venn-diagrams showing the results of variation partitioning performed on (a) Environmental model (Env) and Geographical model (PCNMG), (b) Environmental model (Env) and Topographic model (PCNMT), and (c) Environmental model (Env) and Directional spatial model (AEM) for benthic diatom metacommuntiy in the study area. Variation explained uniquely and jointly, and the unexplained fractions were shown as the number in each part of the figures (total variation = 1). The significance of each testable fraction was expressed as ■P < 0.1, *P < 0.05, **P < 0.01, ***P < 0.001.
Mentions: Variation partitioning was firstly performed on environmental variables (Env) and geographical spatial variables (PCNMG) for diatom communities. Both sets of variables were significant and could explain 54% variation of diatom communities (Fig. 3a). The variation purely explained by Env and PCNMG was 22% and 12% respectively, while the shared fraction was 21% (Fig. 3a). Env and topographic spatial variables (PCNMT) explained 51% of the community variation. Env alone explained much more than PCNMT (31% and 9%), while both explained 11% community variation (Fig. 3b). Directional spatial variables (AEM) had a unique contribution of 22% to metacommunity structuring, and the total explained variation increased to 65%. Furthermore, the unique faction of Env (3%) turned to be marginally significant (Fig. 3c).

Bottom Line: Our results indicated that both environmental filtering and dispersal processes influenced metacommunity structuring, with dispersal contributing more than environmental processes.Our results highlighted that directional processes had prevailing effects on metacommunity structuring in high mountain streams.Flow directionality, mountain barriers and ecological guilds contributed to a better understanding of the roles that mountains played in structuring metacommunity.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.

ABSTRACT
Stream metacommunities are structured by a combination of local (environmental filtering) and regional (dispersal) processes. The unique characters of high mountain streams could potentially determine metacommunity structuring, which is currently poorly understood. Aiming at understanding how these characters influenced metacommunity structuring, we explored the relative importance of local environmental conditions and various dispersal processes, including through geographical (overland), topographical (across mountain barriers) and network (along flow direction) pathways in shaping benthic diatom communities. From a trait perspective, diatoms were categorized into high-profile, low-profile and motile guild to examine the roles of functional traits. Our results indicated that both environmental filtering and dispersal processes influenced metacommunity structuring, with dispersal contributing more than environmental processes. Among the three pathways, stream corridors were primary pathway. Deconstructive analysis suggested different responses to environmental and spatial factors for each of three ecological guilds. However, regardless of traits, dispersal among streams was limited by mountain barriers, while dispersal along stream was promoted by rushing flow in high mountain stream. Our results highlighted that directional processes had prevailing effects on metacommunity structuring in high mountain streams. Flow directionality, mountain barriers and ecological guilds contributed to a better understanding of the roles that mountains played in structuring metacommunity.

No MeSH data available.


Related in: MedlinePlus