Journal of Undergraduate Research


entomophilic nematode diversity, Beaver Dam Wash National Conservation Area


Life Sciences




The Beaver Dam Wash National Conservation Area is considered an important biodiversity hotspot for the Western United States. The wash is an ecotone on the Northeastern edge of the Mojave Desert and is directly adjacent to both the Colorado Plateau and the Great Basin. Thus, this area contains various species of flora and fauna from each of the surrounding biomes. Prior research of the Beaver Dam Wash has documented high aboveground biodiversity for a desert ecosystem however no research has been conducted on belowground diversity. For this reason we chose to characterize the diversity and distribution of entomophilic nematodes, as they are commonly used as a biological indicator to the surrounding ecosystems. We hypothesized that because plant and insect biodiversity is high here, we would also find a diversity of entomophilic nematodes that is higher than the surrounding areas. To test this hypothesis we collected soil samples from 15 sample sites representative of the diversity of the different ecological communities. We tested for patterns of codistribution between entomophilic nematodes and environmental variables, such as plant cover, proximity to water, presence of organic matter, elevation, ecosystem classification, and soil chemistry. We extracted nematodes from the soil samples and sequenced the 28s rDNA region of representative individuals from each sample. Nematode diversity was high; one species was broadly distributed, 6 others were more patchily distributed. No correlation was found between above ground factors. Correlation was found in the soil chemical properties (soil pH, electrical conductivity and percent soil moisture). The soil chemical properties showed no significance with ppm phosphorus, ppm potassium, and percent organic matter. We conclude that the distribution of entomophilic nematodes in this ecological confluence is strongly associated with certain soil chemical properties and correlates with high aboveground diversity.

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