BackgroundPlants in a seasonal environment that become close to the artificial lake after dams construction may have enhanced growth or die due to the new conditions. Changes in mortality or growth rates lead to changes in community diversity, and we do not know if the community functions will change; our main hypothesis was that a few years after impoundment, species richness and diversity will increase because the increased supply of water would favor the establishment of water-associated species. Therefore, we evaluated the consequences of proximity of three dry seasonal forests to the water table after damming, with a dynamic evaluation of the species studied to understand changes in diversity in these areas. We sampled 60 plots of 20×10 m in each forest and measured all trees with a diameter equal to or greater than 4.77 cm before damming and 2 and 4 years after damming. We calculated dynamic rates and compared species changes during these periods. We also compared diversity and richness using Shannon index and rarefaction curves.ResultsMany species had high dynamic rates and many trees of specialists of dry forests died; conversely, others had high growth rates. Some typical species of riparian forests were found only after damming, also enhancing forest richness in deciduous forests. In general, the deciduous forest communities seemed to change to a typical riparian forest, but many seasonal specialist species still had high recruitment and growth rate, maintaining the seasonal traits, such as dispersion by wind and deciduousness in the forests, where an entire transformation did not occur.ConclusionsWe conclude that even with the increment in basal area and recruitment of many new species, the impacts of damming and consequent changes will never lead to the same functions as in a riparian forest.

中文翻译：

---

树木组成和生物多样性的快速变化：大坝对干燥季节性森林的影响

背景 大坝建设后靠近人工湖的季节性环境中的植物可能会因新条件而加速生长或死亡。死亡率或增长率的变化导致群落多样性的变化，不知道群落功能是否会发生变化；我们的主要假设是，蓄水几年后，物种丰富度和多样性将增加，因为水供应的增加将有利于与水相关的物种的建立。因此，我们评估了筑坝后三个干燥的季节性森林靠近地下水位的后果，并对所研究的物种进行了动态评估，以了解这些地区的多样性变化。我们在每片森林中采样了 60 个 20×10 m 的样地，测量了所有直径等于或大于 4 的树木。筑坝前 77 厘米，筑坝后 2 年和 4 年。我们计算了动态速率并比较了这些时期的物种变化。我们还使用香农指数和稀疏曲线比较了多样性和丰富度。结果许多物种的动态率很高，许多干旱森林专家的树木死亡；相反，其他人的增长率很高。一些典型的河岸林种是在筑坝后才发现的，也增加了落叶林的森林丰富度。总体而言，落叶林群落似乎转变为典型的河岸林，但许多季节性特种树种仍然具有较高的补充和生长速度，保持了森林中的风散落和落叶性等季节性特征，从而实现了整个转变。不会发生。