Limnetica 35

Zooplankton dispersal may regulate population dynamics and the structure of aquatic communities. Zooplankton and other aquatic invertebrates, such as freshwater bryozoans, are potentially dispersed overland by abiotic vectors (e.g., wind, rain and water flow) or by organisms (e.g., waterfowl and insects), and although these dispersal vectors have been widely studied, the importance of dispersal by wind remains controversial. In addition, little information is available on passive deposition rates and the differentiation between dry deposition (sedimentation from the air) and wet deposition (from rainfall). In the present study, we quantified zooplankton propagule dispersal by passive deposition from the air and rainfall using deposition collectors designed to gather samples from dry or wet atmospheric deposition. The collectors were located in two regions with distinct limnologic and topographic characteristics: Doñana National Park and Ruidera Natural Park. In Doñana, we also used windsocks to intercept the dormant propagules dispersed by wind, and a larger number were collected in the dry atmospheric deposition collector than in the wet one. Moreover, the deposition of dormant propagules was only related to the meteorological variables, wind direction and temperature, and most of the propagules appeared to arrive in Doñana from the northwest. Our results indicate that overland dispersal by wind and rain is relatively infrequent and probably limited to a few zooplankton species. Despite the few dormant propagules that were collected, they were present in passive deposition collectors and windsocks. Aerial overland dispersal at low rates implies long-term relevance to the genetic structure of zooplankton and their colonization of water bodies.