Drastic loss of insects (Lepidoptera: Geometridae) in urban landscapes in a tropical biodiversity hotspot

Abstract

Accelerating urbanization of natural areasis a particularly important threat to biodiversity in tropical countries. Understanding how this phenomenon affects different groups of the fauna is essential to develop conservation actions We evaluate the effects of urbanization on species diversity and composition of geometrid moths in a tropical biodiversity hotspot in southern Ecuador. Moths were collected at different land-use types: forest, forest-pasture, pasture, and urban. We collected a total of 3064 moths representing 299 morphospecies. Species richness of geometrid moths decreased drastically in the more urbanized areas and moth communities differed strongly in composition between the investigated habitats. Community composition was mainly affected by floristic composition and degree of urbanization. Beta diversity components between land-use types depend on the degree of disturbance, with turnover among communities dominant in initial transitions and nestedness prevailing at later stages of transitions. In summary, moth assemblages in this tropical biodiversity hotspot are not only severely impoverished due to urbanization, but the remaining assemblages are strongly different from those found in natural ecosystems. Implications for insect conservation. To mitigate negative effects we recommend a more cautious development of urbanized areas in the region through the creation of more green space within the city, mainly with high diversity of native plants which can serve as potential hosts for caterpillars of moths and multiple other insects.