نتایج جستجو برای: vegetation types forb

تعداد نتایج: 531616  

Journal: :Electr. J. Comb. 2007
Richard P. Anstee N. Kamoosi

The present paper continues the work begun by Anstee, Ferguson, Griggs and Sali on small forbidden configurations. We define a matrix to be simple if it is a (0,1)-matrix with no repeated columns. Let F be a k× l (0,1)-matrix (the forbidden configuration). Assume A is an m×n simple matrix which has no submatrix which is a row and column permutation of F . We define forb(m,F ) as the largest n, ...

Journal: :Ecological applications : a publication of the Ecological Society of America 2007
Julia A Klein John Harte Xin-Quan Zhao

We investigated experimental warming and simulated grazing (clipping) effects on rangeland quality, as indicated by vegetation production and nutritive quality, in winter-grazed meadows and summer-grazed shrublands on the Tibetan Plateau, a rangeland system experiencing climatic and pastoral land use changes. Warming decreased total aboveground net primary productivity (ANPP) by 40 g x m(-2) x ...

Journal: :Global change biology 2012
H Wayne Polley Virginia L Jin Philip A Fay

Dynamic global vegetation models simulate feedbacks of vegetation change on ecosystem processes, but direct, experimental evidence for feedbacks that result from atmospheric CO2 enrichment is rare. We hypothesized that feedbacks from species change would amplify the initial CO2 stimulation of aboveground net primary productivity (ANPP) of tallgrass prairie communities. Communities of perennial ...

2004
EDWARD W. BORK JOHN W. WALKER

Calibrated predictive relationships obtained from simple and multiple regression of thematic mapper or broad-band (BB) and 1.4 nm interval or narrow-band (NB) spectral data were evaluated for quantifying 11 rangeland components (including total vegetation, forb, grass, shrub, litter, and bare soil) and distinguishing among 6 long-term grazing treatments of sagebrush steppe. In general, all 4 da...

2009
C. S. Wallace M. B. Dale

In this paper, we examine possible sources of hierarchical (nested) structure in vegetation data. We then use the Minimum Message length principle to provide a rational means of comparing hierarchical and non-hierarchical clustering. The results indicate that, with the data used, a hierarchical solution was not as efficient as a nonhierarchical one. However, the hierarchical solution seems to p...

2014
Lovisa Lind Christer Nilsson Christine Weber

Riparian zones support some of the most dynamic and species-rich plant communities in cold regions. A common conception among plant ecologists is that flooding during the season when plants are dormant generally has little effect on the survival and production of riparian vegetation. We show that winter floods may also be of fundamental importance for the composition of riverine vegetation. We ...

2012
Sarah E. Pabian Nathan M. Ermer Walter M. Tzilkowski Margaret C. Brittingham

Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas...

2015
Akasha M. Faist Heather Stone Erin A. Tripp Eric J. Jokela

Mastication is a forest fuel thinning treatment that involves chipping or shredding small trees and shrubs and depositing the material across the forest floor. By decreasing forest density mastication has been shown to lessen crown fire hazard, yet other impacts have only recently started to be studied. Our study evaluates how mastication treatments alter the density and composition of soil see...

Journal: :U.S. Geological Survey professional paper 2023

First posted April 21, 2023 For additional information, contact: Director, Northern Prairie Wildlife Research CenterU.S. Geological Survey8711 37th Street SoutheastJamestown, ND 58401Contact Pubs Warehouse Keys to Dickcissel (Spiza americana) management include providing dense, moderate-to-tall vegetation, particularly with a well-developed forb component, and moderately deep litter. Dickcissel...

Journal: :U.S. Geological Survey professional paper 2023

First posted January 25, 2023 For additional information, contact: Director, Northern Prairie Wildlife Research Center U.S. Geological Survey8711 37th Street Southeast Jamestown, ND 58401Contact Pubs Warehouse Keys to Clay-colored Sparrow (Spizella pallida) management include providing grasslands with a shrub or forb component shrub-dominated edge habitat, which includes dense grass and moderat...

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