Wind and Water Dispersal of Wetland Plants Across Fragmented Landscapes

Abstract

Biodiversity in wetlands is threatened by habitat loss and fragmentation, of which agricultural activities often are a cause. Dispersal of plant seeds via wind and ditches (water) may contribute to connecting remnant wetland plant populations in modern agricultural landscapes, and help to maintain and restore biodiversity. We developed a spatially explicit model to assess the relative importance of dispersal by wind and dispersal by water through drainage ditches for two wetland plant species in agricultural landscapes: a typical wind disperser and a typical water-disperser. Simulation results show that the typical wind disperser had a much higher capability to disperse by wind (90th percentile <30 m) than the typical water-disperser (90th percentile <2 m). Surprisingly, the capability to disperse via water was similar for the two species: 90th percentile dispersal distances following a combination of wind and water dispersal were between approximately 100 and 1000 m. Dispersal by water transported more seeds over long distances for both species. The main determinants for dispersal distance by water were roughness of the ditch (determined by, for example, bank vegetation) and the presence of obstructions (for example, culverts). Density or direction of the ditch network did not seem to affect water dispersal distances substantially. From a biodiversity conservation perspective, it would be most useful if areas with suitable riparian wetland habitat were intersected with a network of shallow ditches with a high roughness promoting seed deposition. These areas should then be connected to other suitable areas by a few regularly cleaned ditches with no obstructions and low seed trapping probability.

Ditch network sustains functional connectivity and influences patterns of gene flow in an intensive agricultural landscape

“…In contrast to L. europaeus, O. aquatica was found almost exclusively in stagnant ditches, where wind may be the main driver of hydrochorous propagule dispersal. Several studies have shown that wind-driven hydrochory can be efficient, but with lower observed dispersal distances than observed in lotic systems (Soomers et al, 2010(Soomers et al, , 2013.…”

Artificial Aquatic Ecosystems

“…The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results. Bird habitat Open water salt marsh management and mosquito ditches USA [191] Integrated marsh management USA [192] Rice fields Philippines [193], Brazil [189], China, Japan [194], France [195] [197,198] Wetland/aquatic plant habitat Paddies and ditches China [199,200] USA [191] Hot springs swimming pools and baths Turkey [211] …”

Zoochorous dispersal of freshwater bivalves: an overlooked vector in biological invasions?

“…In order to develop comprehensive IAS prevention and control measures, species risk assessments must consider not only broad invasion pathway categories, but also specific vectors (Essl et al, 2015). Currently, however, our understanding of the natural dispersal processes operating between hydrologically unconnected water bodies remains limited (Soomers et al, 2013;Incagnone et al, 2015;Coughlan et al, 2017a).…”