Departamento de Ciências Ambientais, Instituto de Florestas, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brasil.
Centro Nacional de Pesquisa de Solos, Empresa Brasileira de Pesquisa Agropecuária, Rio de Janeiro, Rio de Janeiro, Brasil.
PLoS One. 2019 Aug 1;14(8):e0212725. doi: 10.1371/journal.pone.0212725. eCollection 2019.
Agricultural landscapes are seen as areas of extreme importance for studying and developing strategies which integrate biodiversity conservation and ecosystem services with food production. The main strategies for intensifying agriculture are based on conventional agricultural practices of frequently using inputs for fertilization and correcting soil pH. Some studies show that these practices generate impacts on nearby forest fragments through soil contamination and increasing nutrient content. The objective of this study was to identify the impacts on the functional groups of sciophilous (late successional/shade-tolerant species) and heliophilous (pioneer/sun-loving) species of a tree community of 14 forest fragments near pasture areas and agricultural areas under conventional practices, raising the hypothesis that higher-fertility forest fragments adjacent to intensive agriculture modify the floristic composition of the tree community. Consequently, this study is based on the following questions: i) Do forest fragments within intensive farming environments present differences in floristic composition of species?; ii) Does the soil fertility influence the tree species composition?; iii) Which variables influence species abundance and richness in the forest fragments with different types of use around their environment? The floristic composition of fragments close to agricultural areas are more similar to each other than the composition of fragments close to pasture areas. Furthermore, the General Linear Model (GLM) results show a clear influence of the intensive farming environment on the richness and abundance of the two functional groups in the forest fragments, directly benefiting the abundance of heliophilous species, which are also benefited by the greater declivity and smaller fragment area, while the abundance of sciophytes is negatively correlated with these last two variables. The increase of calcium content is beneficial for the richness of heliophilous species, while the increase in phosphorus content influences a reduction in the richness of sciophyte species, which also strongly respond to the isolation between fragments. The results indicate a dominance trend of pioneer species in fragments with nutritionally enriched soils, providing evidence that the intense adoption of inputs in cultivated areas causes concrete impacts on the diversity of the tree community.
农业景观被视为研究和制定将生物多样性保护和生态系统服务与粮食生产相结合的战略的重要领域。强化农业的主要策略是基于常规农业实践，频繁使用肥料和纠正土壤 pH 值。一些研究表明，这些做法通过土壤污染和增加养分含量对附近的森林片段产生影响。本研究的目的是确定常规实践下农田和放牧区附近的 14 个森林片段的喜阴（晚生/耐荫物种）和喜光（先锋/喜阳光物种）树种功能群受到的影响，提出了以下假设：邻近集约化农业的高肥力森林片段会改变树种组成。因此，本研究基于以下问题：i）集约化农业环境中的森林片段在物种的植物区系组成上是否存在差异？；ii）土壤肥力是否影响树种组成？；iii）在不同利用类型的森林片段中，哪些变量会影响物种的丰度和丰富度？靠近农业区的片段的植物区系组成彼此之间更为相似，而靠近牧场区的片段则不然。此外，广义线性模型（GLM）结果表明，集约化农业环境对森林片段中两种功能群的丰富度和丰度有明显影响，直接有利于喜光物种的丰度，较大的坡度和较小的片段面积也有利于喜光物种的丰度，而喜阴植物的丰度与后两个变量呈负相关。钙含量的增加有利于喜光物种的丰富度，而磷含量的增加则影响喜阴物种丰富度的减少，这些物种对片段间的隔离也有强烈的反应。结果表明，在营养丰富的土壤中，先锋物种有占优势的趋势，这为集约化农业地区投入品的大量使用对树种多样性造成具体影响提供了证据。
