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])

研究问题
虽然此前关于红树林的研究已证实边缘距离效应（edge effect）和周边景观类型（neighborhood）对入侵性的重要影响，但尚无研究分析两者之间的交互作用。为填补这一空白，我们探究了周边景观类型与边缘效应的交互作用对受保护红树林区域被非本地树种入侵性的影响。

研究地点
巴西塞阿拉州福塔莱萨市科科州立公园。

研究方法
公园周边区域被划分为六种土地利用类型。通过按周边景观类型分层随机抽样，我们沿从公园边缘到内部的样线，将10×10米的样方分配到三个距离等级（0、30、60米）中。在每个样方内，我们量化了成熟层和更新层中非本地树木的多度与丰富度；确定了非本地和本地树木的物种组成；并测量了冠层覆盖度、土壤pH值及电导率。

研究结果
通过广义线性模型（GLM）分析，我们发现周边景观类型与边缘效应并未产生交互作用，而是各自发挥独立影响：随着与边缘距离的增加，非本地物种的多度和丰富度降低；周边为自然植被的区域中，物种丰富度更低。这似乎与盐度相关，因为广义线性模型显示土壤电导率与非本地物种多度之间存在负相关关系。与边缘的距离并未影响更新层非本地物种的多度，表明距离效应并非由边缘的繁殖体压力所致。周边景观类型与边缘效应的交互作用影响物种组成，在公园边缘或潮汐影响较低的周边区域的样方中，非本地物种占主导地位。

结论
这些发现表明，城市红树林的边缘效应和周边景观类型通过盐度衰减作用，对入侵植物的定殖具有重要影响。

数据使用说明
对数据集和代码信息感兴趣的同仁，请联系通讯作者拉斐尔·科斯塔（Rafael Costa），邮箱：[e-mail]。