Responses of Birds, Rodents, and Vegetation to Livestock Exclosure in a Semidesert Grassland Site

Abstract

Livestock have been excluded from a 3,160-ha range in southeastern Arizona since 1968. Compared to an adjacent continuously grazed area, in 1981-82 a protected upland site supported 45% more grass cover, a comparatively heterogeneous grass community, and 4 times as many shrubs. Grama grasses (Bouteloua spp.) were equally common in and outside the exclosure, while a variety of other species, especially plains lovegrass (Eragrostis intermedia) and Arizona cottontop (Trichachne cal~ornicum) were much more abundant on the protected site. The grazed area supported significantly higher numbers of birds In summer, while densities did not differ in winter. Rodents were significantly more abundant inside the protected area. Species of birds and rodents more common in the grazed area included those typical of more xeric lowland habitats and those preferring open ground for feeding. Species more common on the protected site were those which characterize semidesert or plains grasslands, and which prefer substantial grass or shrub cover. Grazing appeared to favor birds as a class over rodents.

Field <sup>13</sup>CO<sub>2</sub> pulse labeling reveals differential partitioning patterns of photoassimilated carbon in response to livestock exclosure in a <i>Kobresia</i> meadow

“…These results are not consistent with several works that have demonstrated exclosures having positive effects on the growth of the vegetation (Morris and Jensen, 1998;Derner et al, 2006;Bock et al, 1984;Cheng et al, 2011). However, other studies have shown that exclosure is detrimental to the vegetation because of the lack of livestock grazing (McNaughton, 1983;Knapp and Seastedt, 1986).…”

“…Livestock exclosures have a potential value in assessing the effects of grazing upon vegetation and C sequestration in the grasslands (Bock et al, 1984;Cheng et al, 2011;He et al, 2011;Li et al, 2012;Su et al, 2003). Exclosures appear to favor higher community diversity and productivity compared with grazing in the arid grasslands (Bock et al, 1984;Cheng et al, 2011).…”

“…Exclosures appear to favor higher community diversity and productivity compared with grazing in the arid grasslands (Bock et al, 1984;Cheng et al, 2011). Furthermore, grazing exclosures are widely used as a management practice to restore degraded grasslands Su et al, 2003).…”

Impacts of large herbivorous mammals on bird diversity and abundance in an African savanna

“…This lack of eVect may largely be due to rotational grazing and low stocking rates within KLEE. Results from other studies indicate that cattle generally have an adverse eVect on bird diversity, with grazed areas supporting fewer bird species (Bock et al 1984;Gonnet 2001;Taylor 1986;Temple et al 1999).…”

“…Cattle generally have negative eVects on bird diversity and abundance (Bock et al 1984;Taylor 1986;Temple et al 1999;Gonnet 2001;Soderstrom et al 2001; but see Knopf 1996). However, little research is devoted to understanding how large wild mammals inXuence birds, either directly or indirectly.…”