Effects of habitat fragmentation along altitudinal gradients on two monophagous insects in Tongariro National Park, New Zealand

Climate change and landscape fragmentation are two major threats for global terrestrial biodiversity. In particular, habitat size, habitat quality and isolation are influenced by climate change and landscape fragmentation. Within the concept of meta-population biology, the survival of species in fragmented landscapes is mainly due to these three environmental factors. To cope with rising temperatures, stenotherm species such as mobile insects may migrate to higher and therefore cooler regions. However, at increasing altitudes, habitat quality can change. Spatial and temporal “bottlenecks” are a particular risk, especially for monophagous insects e.g. if the appropriate host plants are still restricted to lower altitudes. This project investigates whether increases in population dynamics along an altitudinal gradient will result in higher species requirements of habitat quality and habitat size. Spatial distribution of the endemic scrub species Hebe stricta, habitat quality and abundance of two herbivore specialists, Trioza obscura (Homoptera: Psylloidea) and an unknown gall midge (Diptera: Cecidomyiidae), were mapped along a subalpine stream system in the Tongariro National Park, New Zealand. The poster will present first results of the effects of habitat fragmentation on monophagous insects and their host plants along altitudinal gradients.