High incidence of exotic ostracods in the rice fields of a protected Mediterranean wetland

AbstractMediterranean rice fields are suited for biological invasions, as they are human-impacted temporary water bodies filled during summer, a hot period with scarce rains in the area. These anthropogenic ecosystems have been previously identified as potential gateways for exotic ostracods to colonize nearby wetlands. In this work, we aimed at comparing the rice fields ostracod composition and a shallow lake in a protected Mediterranean wetland (Albufera N2000 site, Eastern Iberian Peninsula). We found 37 ostracod species, 13 of which were considered exotic. Rice fields harbored the highest number of both native and exotic ostracod taxa (16 and 12 species, respectively). Our hypothesis that exotic species were more abundant during summer, whereas native species dominated the community in winter was confirmed by the analysis of temporal changes along the rice field cycle. Comparing the ostracod composition of rice fields with that of the littoral and central parts of the hypertrophic Lake Albufera showed a clear differentiation according to a spatially constrained cluster analysis, with the richest ostracod community corresponding to the rice fields, whereas the center of the lake, with scarce vegetation, had the lowest species richness. Finally, we suggest some criteria that could be followed to consider an ostracod species as native or exotic when its origin is unknown and discuss the potential origin of the exotic species found, the pathways they might have used to arrive and to establish in new areas, and the biological traits that may facilitate the spread of ostracods over new areas after their arrival.Keywords: alien crustaceansfreshwater invasionsOstracodapaddy fieldsshallow lakeDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsWe wish to thank the staff responsible of the sampling campaigns, B. Dies (Fundació Assut), G. Valieri (SIPCAM) and SEO/BirdLife (Valencia). We would also like to thank P. Mateache, former director of the Albufera N2000 site; M. Zizlavsky for his assistance in sample processing; and all SEO/BirdLife volunteers for their assistance during sampling campaigns. Giles Miller is greatly thanked for his support during the stay of MB-R at the NHM. The SCSIE microscopy personnel at the University of Valencia are acknowledged for their help with SEM imaging. We are very grateful to the anonymous reviewers for their helpful suggestions on a previous version of the manuscript.FundingThis publication is part of I + D + i project PID2020-112959GB-I00, funded by MCIN/AEI/10.13039/501100011033. This research was also supported by Consellería de Innovación, Universidades, Ciencia y Sociedad Digital (Comunitat Valenciana Government), though the project EXOCRUST (code AICO/2020/182). SEO/BirdLife studies on macroinvertebrate communities in rice fields were funded by Conselleria de Agricultura, Desarrollo Rural, Emergencia Climática y Transición Ecológica (Comunitat Valenciana Government). M. Bisquert-Ribes is recipient of a predoctoral grant (FPU19/02264) founded by Ministerio de Educación y Formación Profesional (Spanish Government).Disclosure statementNo potential conflict of interest was reported by the authors.Data Availability StatementData are available from the authors upon reasonable request.