Correlation of the Local Distributions of Dipodomys microps and D. merriami and of the Annual Grass Bromus rubens

An Invasive Grass and a Desert Adapted Rodent: is there an Effect on Locomotory Performance and is it Modified by Prior Experience or Familiarization?

“…My results similarly demonstrate negative effects, specifically pertaining to locomotion. These findings, together with the results of previous studies (Rowland and Turner 1964;Congdon and Roest 1975;Germano et al 2001;Nelson et al 2009, Rieder et al 2010, Freeman et al 2014, suggest that any benefits provided by the increase in cover do not make up for other detrimental aspects associated with the vegetation, such as impediment to locomotion.…”

“…The lack of interaction, however, again supports the idea that the overall differences observed between animals from Veldt and non-Veldt habitat of origins were not due to grass density as much as simply the grass itself and experience with it. To my knowledge, no studies that assess the effects of invasive plants on native rodents (Rowland and Turner 1964;Congdon and Roest 1975;Yensen et al 1992;Schooley et al 1996;Germano et al 2001;Sammon and Wilkins 2005;Nelson et al 2009;Rieder et al 2010, Freeman et al 2014) have looked at the effects of different densities of the plant; instead they have looked only at the effects of presence/absence of the plant. This is an area in which further study is needed, especially when an invasive is extremely difficult to fully eradicate and the realistic result of management efforts is a thinner distribution of the invader rather complete removal of it.…”

“…As a result, rodent abundance and diversity often declines in response to plant invasion. For example, Rowland and Turner (1964) found the abundance of the Chisel-toothed kangaroo rat (Dipodomys microps) to be inversely related to the abundance of exotic brome grass in Nye County, Nevada, and speculated that Reynolds' (1950) hypothesis that dense grass interferes with escape from predators depends upon the density of the grass. Similarly, Nelson et al (2009) found that ungrazed Texas kangaroo rat (D. elator)…”

“…For example, the animals could have been stopping because they did not know how best to proceed, they could have been stopping because they felt safe in the grass and were using it as cover, or they could have been stopping because they felt unsafe and were being vigilant. In several studies that look at the effects of invasive plants on native rodents (Rowland and Turner 1964;Congdon and Roest 1975;Yensen et al 1992;Schooley et al 1996;Germano et al 2001;Sammon and Wilkins 2005;Nelson et al 2009;Rieder et al 2010, Freeman et al 2014, the plants, like Veldt grass, offer substantial cover. However, especially in those studies with kangaroo rats (Rowland and Turner 1964;Congdon and Roest 1975;Germano et al 2001;Nelson et al 2009, Rieder et al 2010, Freeman et al 2014), the invasive plants imposed overall negative effects.…”

“…In several studies that look at the effects of invasive plants on native rodents (Rowland and Turner 1964;Congdon and Roest 1975;Yensen et al 1992;Schooley et al 1996;Germano et al 2001;Sammon and Wilkins 2005;Nelson et al 2009;Rieder et al 2010, Freeman et al 2014, the plants, like Veldt grass, offer substantial cover. However, especially in those studies with kangaroo rats (Rowland and Turner 1964;Congdon and Roest 1975;Germano et al 2001;Nelson et al 2009, Rieder et al 2010, Freeman et al 2014), the invasive plants imposed overall negative effects. Specifically, these studies found that the cover created by invasive plant species created often impenetrable thicket for desert-adapted kangaroo rats that rely on open ground to forage and avoid predation (Bartholomew and Caswell 1951;Price 1978;Goldingay et al 1997), and resulted in a decline of kangaroo rat abundance.…”