Central University of Kerala, Periya, Kerala, 671316, India.
Sci Rep. 2022 Jul 14;12(1):12003. doi: 10.1038/s41598-022-16243-x.
Urbanization is a crucial driver of environmental and biodiversity change. It is suggested that urbanization favours generalist and invasive species and might harm specialists of natural and semi-natural habitats. In this study, we examined how an urbanization gradient and environmental gradients in the habitat area, habitat diversity, elevation, and proportion of built-up area influenced the abundance and richness of ants within tropical forest islet habitat in south India. We used abundance (proportional trap incidence) of overall ants, native ants, invasive ants, and Anoplolepis gracilipes-a globally notorious invasive ant of possible south Asian origin-and rarefied richness as the response variables. We found that native ant abundance was greater and A. gracilipes abundance was lesser in less-urbanized landscape compared to moderately-urbanized and highly-urbanized landscape. The richness of ants and abundance of overall and invasive ants were unaffected by the urbanization. We also found that none of the measured environmental gradients but habitat diversity influenced abundance of overall ants, native ants, overall invasive ants, and richness of ants; however, A. gracilipes abundance was negatively correlated with habitat diversity. Ant species composition of less-urbanized landscape was distinct from that of higher urbanization levels. The richness and abundance of native ants and abundance of non-A. gracilipes invasive ants decreased with the abundance of A. gracilipes. Because the forest islets of all three urbanization levels supported similar richness of native ants, the urbanization seems not to have an adverse effect for the native ants of native forest islets. The increasing population of A. gracilipes in urban green islets, however, is a concern. Future studies might investigate its effect on other invertebrates of epigeal and soil strata.
城市化是环境和生物多样性变化的关键驱动因素。有人认为，城市化有利于普通物种和入侵物种，可能会对自然和半自然栖息地的专家造成伤害。在这项研究中，我们研究了城市化梯度以及栖息地面积、栖息地多样性、海拔和建成区比例等环境梯度如何影响印度南部热带森林岛屿栖息地内蚂蚁的丰度和丰富度。我们使用了总体蚂蚁、本地蚂蚁、入侵蚂蚁和 A. gracilipes（一种可能起源于南亚的全球著名入侵蚂蚁）的丰度（比例陷阱发生率）以及稀少丰富度作为响应变量。我们发现，与中度城市化和高度城市化景观相比，在城市化程度较低的景观中，本地蚂蚁的丰度更高，A. gracilipes 的丰度更低。蚂蚁的丰富度以及总体和入侵蚂蚁的丰度不受城市化的影响。我们还发现，除了栖息地多样性外，没有任何测量的环境梯度会影响总体蚂蚁、本地蚂蚁、总体入侵蚂蚁和蚂蚁丰富度的丰度；然而，A. gracilipes 的丰度与栖息地多样性呈负相关。城市化程度较低的景观中的蚂蚁物种组成与较高城市化水平的景观不同。本地蚂蚁的丰富度和丰度以及非 A. gracilipes 入侵蚂蚁的丰度随着 A. gracilipes 的丰度而降低。由于这三个城市化水平的森林岛屿都支持着相似的本地蚂蚁丰富度，因此城市化似乎对原生森林岛屿的本地蚂蚁没有不利影响。然而，城市绿地中 A. gracilipes 种群的增加令人担忧。未来的研究可能会调查它对其他地上和土壤层无脊椎动物的影响。
