An Investigation into the Impact of the National Wildlife Federation’s Certified Wildlife Habitat Program on Mammalian Species Richness in Urbanized Residential Properties




Busch, Katherine L. M.

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The National Wildlife Federation’s Certified Wildlife Habitat (CWH) program was developed to encourage the planting of native vegetation and to connect people to the outdoors. In reestablishing native flora, this program could hypothetically increase the number of animals in these habitats. To explore this hypothesis, mammalian species richness in urbanized residential properties was surveyed. Large, medium, and small mammal species were observed via camera and Sherman traps in 40 backyard habitats in the Northern Virginia region. Paired testing was carried out with 20 residences in the CWH program and 20 backyard habitats not in the CWH program but within 0.5 km of participating properties. In order to assess the impact of the CWH program the habitat usage frequency by species and the average species richness were compared between CWH and non-CWH habitats. The capture rate per species was compared between the two study groups to examine habitat use intensity. Species richness was contrasted between CWH and non-CWH habitats. Capture rate per species and species richness were also compared between CWH properties that were actively maintained and those that had allowed the program requirements to lapse. Accumulation curves were created for both medium/large and small mammals. Significantly higher capture success was discovered in CWH property results for Eastern gray squirrels (Sciurus carolinensis), Northern short-tailed shrew (Blarina brevicauda), and red fox (Vulpes vulpes), white-tailed deer (Odocoileus virginianus), Virginia opossum (Didelphis virginiana), and domestic cat (Felis catus). No significant difference was observed between the certified and non-certified habitats’ species richness using a t-test on the Shannon’s Diversity Index. After pooling data from all 40 properties for accumulation curves, it was determined that the suggested minimum trapping effort necessary for surveying medium and large mammals is 12 nights. The minimum small mammal trapping effort is larger than 95 trap nights. The precise trapping effort is unknown, due to insufficient sampling time. With a heightened concern about animals in urbanized areas and how they interact with their environments, the results of this study are highly relevant. Animals are affected as people change habitats and ecosystems to fit our desires. Without a strong understanding of the vegetative, insect, and animal relationships within those ecosystems, people do not have the ability to make educated predictions of how our alterations and additions of domestic animals will cause changes in the environment and dependent species. It would be possible to cause undesired increases or decreases in species, due to a lack of understanding of a particular ecosystem’s relationships. Zoonotic illnesses such as Lyme disease are linked to host mammals including deermice, chipmunks, Northern short-tailed shrews, and masked shrews. Due to this human-mammal interaction, medical and political personnel are now interested in the ecological relationships of native flora, small mammals, and their predators. Potential impacts of this study include the clarification of how creating wildlife-friendly urban habitats affect the use of the areas by mammals, which could affect how communities, homeowners associations, and politicians set up property management regulations.



Certified Wildlife Habitat Program, Urban, Species richness, Habitat use intensity, National Wildlife Federation, Trapping effort