نتایج جستجو برای: grazing

تعداد نتایج: 15163  

1998
C. L. Alados J. M. Emlen D. C. Freeman

Developmental instability has been used to monitor the well-being of natural populations exposed to physical, chemical and biological stressors. Here, we use developmental instability to assess the impact of grazing on Chrysothamnus greenii and Seriphidium novum shrubs, and Oryzopsis hymenoides grass, common in the arid intermountain west of the U.S.A. Statistical noise in allometric relations ...

2016
Torre James Hovick David M. Engle Sarah M. Nusser

Patch-burn grazing is a management framework that promotes heterogeneity in grasslands, similar to the structure grasslands birds evolved inhabiting. Published studies on patch-burn grazing have been conducted on large, contiguous grasslands and only one of these studies has investigated the reproductive success of grassland birds. We assessed the effects of patch-burn grazing (grazing, one thi...

Journal: :Ecology 2016
Claudia Stein William Stanley Harpole Katharine N Suding

Resilience-based frameworks, founded upon the existence of multiple attractors and regime shifts, have long been applied to complex dynamics of semiarid systems. Utilizing seed addition tests in experimental plantings along grazing gradients, we applied an increase-when-rare criterion to identify bidirectional (states can invade each other) and directional (only one state can invade) transition...

Journal: :FEMS microbiology ecology 2001
M W. Hahn M G. Höfle

Predation by bacterivorous protists in aquatic habitats can influence the morphological structure, taxonomic composition and physiological status of bacterial communities. The protistan grazing can result in bacterial responses at the community and the species level. At the community level, grazing-induced morphological shifts have been observed, which were directed towards either larger or sma...

2000
Sheng Gong Li Yoshinobu Harazono Takehisa Oikawa Ha Lin Zhao Zong Ying He Xue Li Chang

Overgrazing is one of the most primary causes of desertification in semi-arid zones of China. From 1992 to 1994 we conducted a grazing experiment in Naiman (lat. 42◦58′N, long. 120◦43′E, 345 m asl), Inner Mongolia, China to elucidate desertification mechanisms. Our experimental field, which was covered with some short grasses, legumes and forbs, included four plots where grazing sheep numbers d...

2011
W. AYALA E. BARRIOS R. BERMUDEZ

This trial provided information about effects of defoliation frequency, defoliation intensity and winter management (grazing or rest) on the productivity, morphology and plant population of a 3-year-old plantain (Plantago lanceolata) stand. Plant population density declined drastically over time independently of grazing management, with the greatest decrease in summer. Winter grazing had a crit...

2002
Roberta Bottarin Ulrike Tappeiner Meg L. Pollock Colin J. Legg Ian A.R. Hulbert

Experts were interviewed on the grazing preferences of sheep in upland vegetation types and on the responses of plants to grazing. A qualitative model of direction of change in species abundance given different seasonal sheep grazing management regimes was constructed with the expert information. The model was tested against empirical data of sward responses to summer-only grazing. The approach...

2009
Gervasio Piñeiro José M. Paruelo Esteban G. Jobbágy

Grazing ; modifies the structure and function of ecosystems, affecting soil organic carbon (SOC) storage. Although grazing effects on some ecosystem < attributes have been thoroughly reviewed, current literature on grazing effects on SOC needs to be synthesized. Our objective was to synthesize the effects of grazing on SOC stocks in grasslands, establishing the major mechanistic pathways involv...

2010
W. Marc Jones Lauchlan H. Fraser

Wetlands are ecologically and economically important ecosystems with high conservation value. Although wetland vegetation is strongly determined by abiotic factors, grazing disturbance may also be an important influence on this community. We evaluated the effects of livestock grazing on wetland vegetation in marsh and wet meadow zones in intermountain depressional wetlands in the southern inter...

Journal: :Journal of animal science 1992
M D Howard R B Muntifering N W Bradley G E Mitchell S R Lowry

Effects of grazing low-endophyte (Acremonium coenophialum Morgan-Jones and Gams, less than 1% infection) Johnstone (J) or high-endophyte (60% infection) Kentucky-31 (K) tall fescue (Festuca arundinacea Schreb.) on grazing behavior and voluntary intake were studied. Six Angus steers (average initial BW = 326 kg) grazed 1.21-ha plots of each forage cultivar (three steers per cultivar) in four 28-...

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