Grasslands

Risser, Paul G.

doi:10.1007/978-94-009-4830-3_11

Cited by 12 publications

(6 citation statements)

References 207 publications

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“…Plant production in northern temperate grasslands, like YNP, is principally limited by the availability of soil moisture and N (Fay et al., ; Frank, ; Harpole & Tilman, ; Hooper & Johnson, ; Kirchner, ; Parton et al., ; Risser, ). Temporal variation in climate (i.e., precipitation, temperature) influences soil moisture directly and indirectly affects soil N availability by regulating microbial activity.…”

Section: Discussionmentioning

confidence: 99%

“…We developed a conceptual model of the direct and indirect pathways by which herbivores and climate can influence the availability of soil moisture and N (Figure ), the two principal factors that regulate production of temperate non‐calcareous grassland (Fay et al., ; Harpole & Tilman, ; Hooper & Johnson, ; Kirchner, ; Parton et al., ; Risser, ). We hypothesized the following.…”

Section: Methodsmentioning

confidence: 99%

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Manipulating the system: How large herbivores control bottom‐up regulation of grasslands

et al. 2017

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3. Herbivores only had direct effects on plant variables at the dry grassland compared to direct and indirect effects on both plant and soil variables at the mesic grassland.By enhancing leaf N content at both grasslands, grazers shifted the resource controlling NAP from N in ungrazed grassland to moisture, and potentially phosphorus and/or other soil nutrients, in grazed grassland. Synthesis.These results indicate the mechanistic linkage between top-down (herbivore) and bottom-up (soil resource) control of grassland production. Changing the resources that limit net above-ground plant production (NAP) likely has a profound impact on how grazed vs. ungrazed Yellowstone National Park (YNP) grasslands respond to environmental (e.g., climate, atmospheric N deposition) variability.Because grazing enhances leaf N among many types of grasslands, increasing the sensitivity of plant production to the availability of moisture and nutrients other than N may be a general response of grasslands to grazing. K E Y W O R D Sbottom

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Manipulating the system: How large herbivores control bottom‐up regulation of grasslands

et al. 2017

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“…If it can obtain enough of the limiting resource during dormancy it will emerge and flower again. Nitrogen and phosphorus are likely candidates for this resource because they are often limiting in semi‐arid ecosystems (Risser 1985), and both are required for flower and fruit production (Reekie 1997; Epstein & Bloom 2005).…”

Section: Discussionmentioning

confidence: 99%

Causes and consequences of prolonged dormancy for an iteroparous geophyte, Silene spaldingii

Lesica¹,

Crone

2007

Journal of Ecology

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Summary1. Prolonged dormancy, during which a plant does not produce above-ground shoots during one or more growing seasons, is common in temperate herbaceous species, but its role in life history is poorly understood. 2. We analysed stage transitions to determine the consequences of prolonged dormancy for Silene spaldingii , a perennial geophyte of semi-arid grasslands in the Columbia Basin of western North America. We monitored 179 S. spaldingii plants from 1987 through 2005, and analysed demographic rates as a function of plant state and seasonal precipitation. 3. Dormant plants had similar survival and growth to vegetative plants, and were more likely to flower in the following year, resulting in a greater reproductive value being associated with the dormant state. Thus, prolonged dormancy is likely to increase fitness in S. spaldingii . 4. Both external (precipitation) and internal (stage in previous year) factors were associated with S. spaldingii vital rates. Prolonged dormancy was more likely following flowering than after being vegetative, and following a wetter summer and/or drier fall the previous year. 5. Our results suggest that geophytic species may respond to current resource availability in a manner dependent on internal state (previous performance) and suggest that prolonged dormancy plays a role in resource allocation and life history.

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“…1). Grasses show a wide array of morphological and physiological attributes that may contribute to their ecological success in grasslands and savannas (see McNaughton, Coughenour & Wallace 1981;Risser 1985); a comprehensive model applicable to all perennial grasses in a given ecosystem has not yet been proposed. Large herbivores do not seem to have played a key role in South American savannas, as contrasted with palaeotropical savannas.…”

Section: Introductionmentioning

confidence: 99%

Adaptive strategies of perennial grasses in South American savannas

Sarmiento

1992

Journal of Vegetation Science

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Abstract. Morpho‐fimctional features of perennial grasses in South American savannas are considered as adaptive strategies to cope with stress and disturbance factors of savanna environments. The tussock growth form, annual patterns of vegetative growth and reproductive phenology, allocation of carbon and nutrients, and accumulation of standing dead phytomass at the end of the dry season, are discussed in relation to water economy, resistance to drought, photosynthetic rates, growth rhythms, regrowth after drought and fire, seasonal translocation of critical nutrients and carbohydrates, and the total nutrient budget of the grass layer. Different strategies combining various morphological patterns, phenological alternatives and mechanisms for resisting drought and fire exist within the grass flora of each savanna community. The lack of adaptive responses to grazing by large herbivores is a major distinction from African savanna grasses. Many African grasses, either introduced in pastures or colonizing disturbed savannas, do show positive responses to defoliation, including compensatory growth and enhanced photosynthetic rates. Some guidelines for further research are suggested in order to disclose the mechanisms underlying this different behaviour of native and introduced savanna grasses.

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Grasslands

Cited by 12 publications

References 207 publications

Manipulating the system: How large herbivores control bottom‐up regulation of grasslands

Manipulating the system: How large herbivores control bottom‐up regulation of grasslands

Causes and consequences of prolonged dormancy for an iteroparous geophyte, Silene spaldingii

Adaptive strategies of perennial grasses in South American savannas

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