Browsing Journal of Range Management, Volume 57, Number 4 (July 2004) by Title
Now showing items 14-17 of 17
Restoration of communities dominated by false helleboreFalse hellebore (Veratrum californicum Durand) is a native component of high-elevation, meadow-riparian areas of the mountain West that has increased due to historic heavy grazing. In 1991, a study was established in dense stands of false hellebore to evaluate mechanical and chemical control methods to reduce false hellebore and increase the abundance of the other native herbaceous species in these tall-forb communities. Four control methods consisting of the herbicide glyphosate (N-phenophonomethylglycine), mow, mowing in 2 consecutive years (remow), and tillage were used in 1991-1992. Each method was evaluated based on (1) reduction of false hellebore stem densities; (2) response of residual understory species; and (3) effectiveness of seeding a perennial grass and forb mixture to sustain initial treatment control. Stem density of false hellebore and nested frequency data for all species were collected in 1991, 1992, 1995, and 1999. The glyphosate treatment was effective in reducing false hellebore stem density which allowed for recovery of the remnant tall-forb community. The till treatment, while effectively reducing false hellebore stem density, also eliminated the other species in the community, leaving it open to invasive weeds. The mow and remow treatments did not reduce false hellebore stem density, but did allow for recovery of other components of the tall-forb community. Seeding following control treatments had no effect on false hellebore stem densities due to poor establishment. The mechanical treatments were generally more cumbersome in application and limited to gentle topography and well-drained sites without surface rocks. The application of herbicides is much easier and is adaptable to all types of terrain. The use of the herbicide glyphosate gave the best balance of false hellebore control and recovery of the tall-forb community.
Short-term grazing exclusion effects on riparian small mammal communitiesGrazing 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 grasslandsThe 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 RangelandsEffective, 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.