Seasonal river connections modulate community structure in (sub) tropical temporary pools
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Date
2025-12-01
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Publisher
Elservier
Abstract
In natural river systems in arid and semi-arid lands, surrounding floodplains may contain
temporary pools. Some of these may be mainly rain-filled (endorheic systems) while others may
be partly rain-fed but connect to the flooding river during a good rainy season (river-connected
pools). However, how seasonal river flooding affects the community structure in temporary
floodplain pools is not well understood, particularly in the Afro-tropical region. Here, we studied
the role of seasonal river connections in modulating water quality and benthic macroinvertebrate
community structure and functional feeding groups in a set of endorheic versus river-connected
temporary pools in a river-floodplain ecosystem in northeastern Tanzania. Benthic
macroinvertebrate communities from the two habitats were significantly differentiated. Spatial
species turnover (β-diversity) was higher in river-connected pools, but endorheic ones supported
a higher taxon richness (alpha diversity). Benthic macroinvertebrate community dissimilarity
between pools was largely determined by turnover rather than by nestedness. Hydrological
connectivity was positively associated with electric conductivity and negatively associated with
nutrient concentrations in the river-connected pools. In addition, the river facilitated fish dispersal,
which likely excluded predation sensitive taxa such as the large branchiopod crustaceans
Streptocephalus bourquinii and Streptocephalus wirminghausi. Taxon richness of collector-
gatherers and scrapers was significantly different between pool types. Indicator species analysis
revealed no specific fauna unique to river-connected pools. This study illustrates that land
management schemes that aim to preserve temporary-pool biodiversity should strive to include
both endorheic and river-connected pools to support high regional biodiversity, potentially with a
priority for the more diverse endorheic systems
Sustainable Development Goals
2: Zero Hunger
6: Clean Water and Sanitation
15: Life on Land