This project will determine the extent to which habitat fragmentation is affecting gene flow in Oenothera harringtonii, an annual Colorado endemic whose habitat is increasingly disturbed by numerous development activities. Oenothera harringtonii has night-blooming flowers that are pollinated primarily by hawkmoths in the evening and matinal bees in the early morning hours. Hawkmoths are known to travel long distances in a single night and may make important contributions to long-distance gene flow, whereas bees tend to forage locally and therefore pollen dispersal may be limited to the local population. However, hawkmoth visitation to O. harringtonii may be lower in fragmented areas due to increased visibility to predators via light pollution and changes to flight and dispersal patterns. Gene flow will be examined through a parentage analysis using highly polymorphic microsatellite markers to examine the genetic consequences of habitat fragmentation on O. harringtonii. Pollinator exclusion treatments will be used to determine the spatial scales over which different pollinators facilitate gene flow. Geospatial analyses will be used to determine fine-scale patterns of gene flow within and between populations. By studying and comparing fragmented and unfragmented populations, this project will yield insights that are directly relevant to the management and conservation of Oenothera harringtonii and will also inform land-use decisions in Colorados middle Arkansas River Valley, an ecosystem of high conservation value. Lab work during summer 2012 will involve genetic analyses of samples collected from parental plants. The REU student will gain experience with a variety of techniques used in molecular ecology, specifically DNA extraction, amplifying DNA by polymerase chain reaction and genotyping individuals using microsatellite markers.