Any way the wind blows ‐ frequent wind dispersal drives species sorting in ephemeral aquatic communities

Abstract

Despite an upsurge of interest in spatial interactions between communities and in the impact of dispersal on ecological and evolutionary processes, dispersal patterns and dynamics in natural metacommunities remain poorly understood. Although passive aerial dispersal of freshwater invertebrates is generally accepted, the frequency and relative importance of wind as a vector is still subject of considerable debate. We assessed the importance of wind dispersal in an invertebrate metacommunity in a cluster of 36 temporary rock pools on an isolated mountaintop in South Africa. Wind dispersal was quantified every four days using nine windsocks (about 1.5 m above rock base), placed in the field during one month. Distance to the nearest pool varied from 2 up to 16 m. Wind direction and speed were monitored for the entire period. About 850 propagules (mostly resting eggs) of 17 taxa were captured. The presence of water in the pools (level of exposure of the dormant propagule bank) and the dominant wind direction were the key factors affecting the yield. Wind speed was much less important.Our results suggest that wind dispersal of propagules from temporary aquatic systems is more frequent than previously thought. This may stabilise the metacommunity by mediating gene flow among populations and facilitating rapid (re)colonisation of patches. On the other hand, wind erosion of the dormant propagule bank may lead to egg bank depletion and local extinction.The measured frequent wind dispersal most likely fuels strong species sorting processes ultimately shaping the structure of the local communities as observed in an earlier study. To elucidate the link between local dispersal rates and their contribution to long range dispersal is a major challenge for future research on aerial dispersal of aquatic invertebrates.

How do freshwater organisms cross the “dry ocean”? A review on passive dispersal and colonization processes with a special focus on temporary ponds

“…In contrast to the above cited results, Vanschoenwinkel et al (2008b) report the absence of crustacean resting stages dispersal by wind among temporary rock pools when they are experiencing their ponding phase. According to these authors, biological vectors are the only effective dispersal agents during the wet phase in temporary ponds.…”

Influence of riparian habitat on aquatic macroinvertebrate community colonization within riparian zones of agricultural headwater streams

“…Zooplankton colonization via wind or rain is also possible especially since our mesocosms were short distances (57 m) from headwater streams that periodically dry up in the summer. Ephemeral aquatic habitats are a source of zooplankton propagules capable of short distance wind dispersal (Caceres and Soluk 2002;Vanschoenwinkel et al 2008). Our unchannelized streams dry up more frequently in the summer and experience overbank flooding more often in the winter than our channelized streams (King et al 2009).…”

“…Anecdotal evidence suggests that zooplankton dispersal occurs passively via animals (waterfowl, amphibians, reptiles, mammals, and insects), wind, rain, and flooding (Bilton et al 2001;Bohonak and Jenkins 2003). Some zooplankton taxa are capable of colonizing new aquatic habitats and mesocosms quickly (Caceres and Soluk 2002;Vanschoenwinkel et al 2008). Introduction of water from outside sources (i.e.…”

The influence of pool volume and summer desiccation on the production of the resting and dispersal stage in a Daphnia metapopulation

“…Furthermore, small pools are more prone to desiccation. During droughts, ephippia are more exposed to wind and birds in the dry sediments (Maguire 1963;Proctor and Malone 1965), which may result in even more dispersal from small, frequently desiccating pools than from large and permanent pools (Vanschoenwinkel et al 2008). It should be noted that we did not measure dispersal itself, but only the production of potential migrants.…”