Linking the spatio-temporal distribution of an edaphic crane fly to its heterogeneous soil environment

The persistence of a species within a habitat patch is determined by the degree to which the habitat meets the species' biotic and abiotic requirements. Local-scale spatio-temporal population dynamics should be structured by the heterogeneity of these factors within the habitat patch. This study relates the abiotic (soil moisture) and biotic (plant community) factors defining a continuous turfgrass environment to the temporal population structure and spatial distribution of Tipula paludosa ontogenetic stages across 3years of investigation. Populations declined greatly from first instar to pupa across all sites. Survival was greatest in soils with higher water-holding capacity. Intra-patch insect spatial distributions were associated with soil moisture but not with plant community distributions. A sink-source dynamic was evident. Low quality habitats could have high first instar populations, but these did not survive until pupation. Where high and low quality habitats intersected, there was a tendency for high quality habitats to be sparsely populated. Tipula paludosa spatio-temporal distributions are dynamic throughout the life cycle. This work suggests that population persistence within a habitat patch is determined by the quality of the habitat, largely defined by soil moisture, and the juxtaposition of high and low quality habitats within the patch.