![]() ![]() Thus, foraging efficiency is reduced because rodents collect fewer seeds as litter depth and biomass increases ( Reed, Kaufman & Kaufman, 2006). For example, when dense, it can take 1 month for grass seeds to reach the soil surface after they are dispersed ( Fowler, 1986). Litter can entrap herbaceous seeds and prevent them from reaching the ground ( Donath & Eckstein, 2010 Rotundo & Aguiar, 2005) where rodents forage. Forager efficiency is reduced when rodents move through the complex architecture of standing and downed litter and when they pursue post-dispersal seeds bound in litter ( Reed, Kaufman & Kaufman, 2006 Thompson & Gese, 2013). ![]() This accumulated litter is negatively related to rodent mean body mass, diversity, richness, and total rodent biomass in a northern shortgrass prairie ( Thompson & Gese, 2013). Suppression of fire and demise of bison ( Bison bison) and prairie dogs ( Cynomys) contribute to high amounts of senescent litter ( Agnew, Uresk & Hansen, 1986 Fuhlendorf et al., 2012). Prior to European settlement, losses regularly occurred from decomposition, fire, and herbivory. Senescent plants generate litter accumulating yearly. In North American grasslands, plant litter is a prevalent component of rodents’ habitats. Restoring natural disturbances may be an important element in conserving rodent communities. A large-scale disturbance can decrease litter which may alter rodent abundance by allowing foragers to gather food more efficiently and detect and escape predators. Accumulated litter lowers rodent density and diversity ( Abramsky, 1978 McCarty, 1978 Thompson & Gese, 2013) and may reduce a keystone species ( Hoffmeister, 1986). Grassland rodents’ security from predation (predation risk) is also altered by plant litter ( Clark & Kaufman, 1991 Longland & Price, 1991). When grasslands lack natural disturbances (sensu Paine (1966) and Sousa (1984)), plant litter accumulates causing rodents to forage inefficiently (harvest fewer seeds or gather fewer nutrients per equivalent time foraging) ( Reed, Kaufman & Kaufman, 2006). High levels of plant litter alter population feedback to resource pulses ( Shenbrot, 2014). Sometimes, however, populations do not grow following pulses ( Baez et al., 2006 Shenbrot, 2014). Small mammal populations in aridlands are regulated by resource pulses which supply food and habitat ( Brown, Reichman & Davidson, 1979). Managers might positively influence grassland rodents by providing a mosaic of varying levels of plant litter. These short term results demonstrate litter’s physical complexity may be equivalent to seed pulses on the responses of nocturnal rodents. After winter, seeded plots had higher kangaroo rat body mass and grasshopper mice abundance than unseeded, reflecting the use of stored seeds. Pocket mice body mass was greater in dense plots. Banner-tailed kangaroo rats had higher abundance, implying reduced predation risk. ![]() Sparse litter treatment had higher total rodent abundance, biomass, and frequency of offspring compared to dense plots indicating use of stored seeds. Rodents were live-trapped during spring and fall 1 year. A prescribed fire removed litter in four of eight plots prior to sowing native seeds 1 year postfire into two burned and two unburned plots. I further hypothesized that kangaroo rats and deer mice would be higher in the seed augmented treatment compared to the unseeded treatment. Specifically, I hypothesized that kangaroo rats, pocket mice, grasshopper mice, and total rodents would be higher in the sparse plant litter treatment than dense litter, whereas deer mice would be lower in sparse plots. The aim of this study was to assess the influence of two levels of plant litter cover and seed densities on nocturnal rodent population characteristics in a semiarid grassland. When natural disturbances are suppressed, litter accumulates becoming physically complex, causing rodents to harvest fewer seeds per equivalent time foraging. Rodent populations in arid grasslands do not always track seed production, possibly due to high levels of plant litter. ![]()
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