Fine‐scale hydrological niche segregation in coastal dune slacks

• Published in: Journal of vegetation science Vol. 32; no. 5
• Main Authors: Dwyer, Ciara, Pakeman, Robin J., Jones, Laurence, Willegen, Lisanne, Hunt, Natalie, Millett, Jonathan, Michalet, Richard
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.09.2021
• Subjects: Coastal waters; coastal wetlands; Community composition; Composition; dune slack; Dunes; Elevation; Environmental restoration; Habitats; Herbivores; Hydrologic regime; Hydrology; microtopography; Nature reserves; niche segregation; Niches; Plant communities; Plant populations; Plant species; sand dunes; Species; succession; topography; Vegetation patterns; Water depth; Water table; Water table depth
• ISSN: 1100-9233; 1654-1103
• DOI: 10.1111/jvs.13085

Questions Hydrological niche segregation is widespread and has been found across a range of different habitats. Different plant species can occupy distinct hydrological niches, and as a result fine‐scale variability in hydrology can structure plant communities. However, these patterns may not be as clear in habitats where differences in hydrology are more short‐lived, such as coastal dune slacks. We explored the extent that the hydrological regime structures dune slack plant communities. Location Ainsdale Coastal Sand Dune National Nature Reserve, UK. Methods Six hundred quadrats were surveyed, 100 in each of six coastal dune slacks. Water table levels are recorded monthly in each slack. Metrics summarising hydrological regime were calculated and adjusted for each quadrat based on elevation. We tested the relationship between water table depth, plant communities and topography across and within dune slacks. Results Half (three) of the slacks showed a significant influence of hydrology on plant community composition. The three that did not were the ones that varied least topographically and contained less diverse plant communities. We also provide indirect evidence of niche segregation by modelling species‐specific responses between mean water table depth and probability of species presence. Conclusions We demonstrate that hydrology is a dominant driver of plant community composition across dune slacks. However, plant communities are not always structured by hydrology, demonstrating the complexity of vegetation patterns. Topographic variation appears to impact plant community patterns, as do successional processes, highlighting the need to create diverse habitats for slack restoration and management. Coastal dune slacks are seasonal wetlands that are rich in diversity. We explored the extent that the hydrological regime structures plant communities. We demonstrate that hydrology is a key driver of plant communities across dune slacks, but not all plant communities are structured by hydrology. Topographic variability and successional processes also appear to impact these plant patterns.