@article{fdi:010075109,
  title = {{A} comprehensive examination of the network position hypothesis across multiple river metacommunities},
  author = {{H}enriques-{S}ilva, {R}. and {L}ogez, {M}. and {R}eynaud, {N}. and {T}edesco, {P}ablo and {B}rosse, {S}. and {J}anuchowski-{H}artley, {S}. {R}. and {O}berdorff, {T}hierry and {A}rgillier, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he hierarchical branching nature of river networks can have a strong influence on the assembly of freshwater communities. {T}his unique structure has spurred the development of the network position hypothesis ({NPH}), which states that the strength of different assembly processes depends on the community position in the river network. {S}pecifically, it predicts that 1) headwater communities should be exclusively controlled by the local environment given that they are more isolated and environmentally heterogeneous relative to downstream reaches. {I}n contrast, 2) downstream communities should be regulated by both environmental and dispersal processes due to increased connectivity given their central position in the riverscape. {A}lthough intuitive, the {NPH} has only been evaluated on a few catchments and it is not yet clear whether its predictions are generalizable. {T}o fill this gap, we tested the {NPH} on river dwelling fishes using an extensive dataset from 28 {F}rench catchments. {S}tream and climatic variables were assembled to characterize environmental conditions and graph theory was applied on river networks to create spatial variables. {W}e tested both predictions using variation partitioning analyses separately for headwater and downstream sites in each catchment. {O}nly 10 catchments supported both predictions, 11 failed to support at least one of them, while in 7 the {NPH} was partially supported given that spatial variables were also significant for headwater communities. {W}e then assembled a dataset at the catchment scale (e.g. topography, environmental heterogeneity, network connectivity) and applied a classification tree analysis ({CTA}) to determine which regional property could explain these results. {T}he {CTA} showed that the {NPH} was not supported in catchments with high heterogeneity in connectivity among sites. {I}n more homogeneously connected catchments, the {NPH} was only supported when headwaters were more environmentally heterogeneous than downstream sites. {W}e conclude that the {NPH} is context dependent even for taxa dispersing exclusively within streams.},
  keywords = {context-dependent ; river network ; environmental heterogeneity ; {FRANCE}},
  booktitle = {},
  journal = {{E}cography},
  volume = {42},
  numero = {2},
  pages = {284--294},
  ISSN = {0906-7590},
  year = {2019},
  DOI = {10.1111/ecog.03908},
  URL = {https://www.documentation.ird.fr/hor/fdi:010075109},
}