• Short-term grazing exclusion effects on riparian small mammal communities

      Giuliano, William M.; Homyack, Joshua D. (Society for Range Management, 2004-07-01)
      Grazing of livestock in streams and associated riparian habitats (hereafter referred to as riparian zones) may affect small mammal communities by influencing vegetation, water quality, and other site characteristics. To better understand these effects, we compared vegetation structure, and abundance and richness of small mammals in grazed riparian zones and similar areas where livestock had recently (1-2 years) been excluded in southwest Pennsylvania, 1998 and 1999. Mammalian species richness and abundance (all species combined, meadow voles [Microtus pennsylvanicus Ord], and meadow jumping mice [Zapus hudsonius Zimmermann]) were greater on sites where livestock had been excluded than grazed areas. These findings are likely the result of greater litter cover and increased vertical vegetation obstruction observed on these sites. Because small mammal communities respond quickly to relaxation of grazing in riparian zones, subsidy programs exist to partially pay for fencing, and landowners may potentially benefit from fencing these areas through improved water quality, erosion control, and livestock health, fencing may be an effective wildlife and grazing management tool.
    • Spatial patterns of light gaps in mesic grasslands

      Derner, Justin D.; Wu, X. Ben (Society for Range Management, 2004-07-01)
      The spatial pattern of light gaps in mesic grasslands in central Texas with contrasting disturbance histories was assessed using patch-based landscape metrics determined from a threshold level (25% of full sunlight), as light intensities below this threshold substantially decrease survival of honey mesquite (Prosopis glandulosa var. glandulosa Torr.) seedlings. The spatial pattern of light gaps, with the exception of edge density, were significantly different between annually-disturbed and non-disturbed grasslands on all sample dates (2 April, 30 April, 29 May, and 26 June 1998). Differences in patch metrics did not occur between non-disturbed grasslands despite contrasting vegetation composition [perennial forbs and perennial bunch (tussock) grasses]. Patch-based landscape metrics of light gaps did vary temporally in both annually-disturbed and non-disturbed grasslands. The structure and spatial configuration of light gaps were distinctly different between annually-disturbed and non-disturbed grasslands: a low density of large patches characterized light gaps in annually-disturbed grassland, whereas non-disturbed grasslands had a high density of small patches. Our findings demonstrate that the current disturbance regime is the principal environmental driver influencing species dominance and composition, and indirectly vegetation structure, which collectively contribute to the observed dynamics of light gap patches in these mesic grasslands. Incorporating spatially explicit consideration of light gap structure and dynamics into experimental studies addressing invasion of weedy plant species such as honey mesquite may be an effective approach to address mechanisms and the ecological significance of disturbance operating as a driver facilitating woody plant invasions in mesic grasslands.
    • Writing Book Reviews for the Journal Of Range Management and Rangelands

      Scarnecchia, David L. (Society for Range Management, 2004-07-01)
      Effective, analytical reviews of recently published books inform readers of their essential content, and evaluate and communicate the value of their content to professional disciplines and the reading public. Such book reviews are widely read contributions to the Society for Range Management's publications, the Journal of Range Management and Rangelands, and are important elements of evaluation and communication within the Society. This paper is designed to assist writers in developing book reviews for the Journal of Range Management and Rangelands. Much of its analysis is relevant to book reviews for other publications. It begins with preliminary considerations for prospective authors. The functions of a book review are explained. Important considerations concerning reading the book are examined. The paper emphasizes the importance of finding a theme for a review. The common parts of a written review, i.e., the introduction, description of content, analysis and evaluation, and closing are considered individually. The paper then examines aspects of editing a review, and addresses some matters of style in writing. It concludes with a brief discussion of the importance of synthesis in developing an effective book review.