Assessing Small Mammal Abundance and Diversity in North Dakota Grasslands PDF Download

Author: Andrew Stephen Wiewel
Publisher:
ISBN:
Category : Biodiversity
Languages : en
Pages : 92

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Book Description
In the Northern Great Plains, small mammals are the primary prey of medium-sized predators and play an important, though poorly understood, role in predator-prey interactions. By developing inexpensive and rapid sampling methods we can better study small mammal populations at the large spatial and temporal scales necessary for understanding these complex interactions. I compared a track tube survey method with mark-recapture and removal surveys and evaluated a track tube index, defined as the number of track tubes with identifiable tracks during a 4-night survey, as a predictor of small mammal abundance estimates. Removal surveys consistently captured more species, and more individuals of those species, than mark-recapture surveys. Track tube surveys detected species commonly captured during mark-recapture and removal surveys but often failed to detect rare species. The track tube index, although generally correlated with small mammal abundance estimates, was a poor predictor of those estimates due to variation in the form (linear vs. curvilinear) and changes in the slope of the relationship between years. I also investigated small mammal-habitat associations in grassland habitats and developed regression models to predict the relative abundance and diversity of small mammals in upland and wet-meadow habitats (macrohabitat models) and the distribution of small mammal capture locations within these habitats (microhabitat models) as a function of soil moisture and vegetation characteristics. Macrohabitat models explained 25-74% of the variation in the relative abundance of different species and 76% of the variation in species diversity in upland and wet-meadow habitats. Important macrohabitat-level predictive variables included soil moisture, percent forb vegetation, percent litter, and litter depth. Microhabitat models explained 5-15% of the variation in the distribution of small mammal captures within upland and wet-land meadow habitats. Important microhabitat-level predictive variables included soil moisture, Robel visual obstruction, vegetation height, and litter depth. Models that predict small mammal abundance, diversity, and distribution in grassland habitats could be integrated with knowledge about avian nesting and predator foraging activities to better understand the effects of spatial and temporal variability of small mammal prey availability on predator-prey interactions in the Northern Great Plains.