Influences of the edge effect and neighborhood landscape on the presence of non-native plants in an urban mangrove protected area

QUESTIONAlthough previous studies in mangroves have demonstrated the importance of the effect of distance from the edge (edge ​​effect) and neighboring landscape type (neighborhood) on invasibility, no study has analyzed interactions between both. To fill this gap, we investigated the effects of the interaction between neighborhood and edge effect on the invasibility of a protected mangrove area by non-native tree species.LOCATIONCocó State Park, Fortaleza, Ceará, Brazil.METHODSThe neighborhood adjacent to the park was classified into six land use categories. Through stratified random sampling by neighborhood type, we allocated 10 x 10 m plots into three distance classes (0, 30, 60 m) following transects from the edge to the interior of the park. In each plot, we quantified the abundance and richness of non-native trees in the mature and regenerating strata; determined the species composition of non-native and native trees; and measured canopy cover, soil pH and electrical conductivity.RESULTSThrough GLM analyses, we found that, instead of interaction, neighborhood and edge-effect exerted isolated effects, with a decrease in the abundance and richness of non-native species with distance from the edge, and lower richness in sectors with natural vegetation in the neighborhood. This appears to be related to salinity, since the GLMs showed a negative relationship between soil electrical conductivity and abundance of non-native species. Distance from the edge did not influence the abundance of regenerating non-natives, indicating that the effect of distance was not caused by propagule pressure at the edge. The interaction between neighborhood and edge effects influenced species composition, with a predominance of non-native species in plots located at the edge of the park or in neighborhoods associated with a lower influence of tides.CONCLUSIONThese findings indicate that the edge effect and the neighborhood of urban mangroves are important in the establishment of invasive plants through salinity attenuation.<br>USE OF DATACollegues interested in data set and code informations should contact the corresponding author, Rafael Costa ([e-mail])