Large African herbivores decrease herbaceous plant biomass while increasing plant species richness in a semi-arid savanna toposequence

Jacobs, Shayne M.; Naiman, Robert J.

doi:10.1016/j.jaridenv.2007.11.015

Cited by 50 publications

(89 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This proved rather time consuming to maintain and from 1982, sheep were permanently excluded from all the exclosures (Hill et al 1992). The results of these experiments are typical of many similar studies (Watts 1981;Jacobs and Naiman 2008;Wigley et al 2014;Moore et al 2015) in that the vegetation inside the exclosure grew taller than the more heavily grazed surrounding vegetation and, more importantly, developed a different species composition. Several plant species, such as ling heather (Calluna vulgaris), which were kept small and rare by the sheep grazing, developed to dominate parts of the exclosures, so even from a distance the vegetation in some of the exclosures appears different from its surroundings (Figure 4).…”

Section: Top-down -Experimental Datamentioning

confidence: 85%

Why is the world green? The interactions of top–down and bottom–up processes in terrestrial vegetation ecology

Wilkinson

Sherratt

2016

Plant Ecology & Diversity

View full text Add to dashboard Cite

A classic question in plant ecology is "why is the world green?" That is, if plants are food for animals why do not animals eat all the available food -changing a 'green world' into a 'brown world'. We first reviewed this question in 2009 and now revisit our arguments in the light of new data and new thinking. Here we argue that (1) the top-down bottom-up dichotomy is probably too simple for understanding a complex system -such as vegetation -rich in feedback processes. (2) Nevertheless it appears that bottom-up processes are generally more important for maintaining the presence of some sort of vegetation while top-down control process are generally more important in determining the type of vegetation at a site. (3) Although this review mainly takes a qualitative and experimental approach to the question, we also argue that simple well-known mathematical models from population ecology can be very informative in thinking about the types of explanations for the green world phenomenon, and demonstrating that it is rarely a simple choice between one form of control or another.

show abstract

Section: Top-down -Experimental Datamentioning

confidence: 85%

Why is the world green? The interactions of top–down and bottom–up processes in terrestrial vegetation ecology

Wilkinson

Sherratt

2016

Plant Ecology & Diversity

View full text Add to dashboard Cite

show abstract

“…Many studies in savanna grasslands have found that large-herbivore grazing increases plant species richness and diversity (e.g., Belsky 1992, Hartnett et al 1996, Bakker et al 2006, Jacobs and Naiman 2008. This response is driven by reduced abundance of, and dominance by, the tall C 4 grasses that are targeted by grazers (Knapp 1985, Milchunas et al 1988, Knapp et al 1999.…”

Section: Discussionmentioning

confidence: 99%

Plant community response to loss of large herbivores differs between North American and South African savanna grasslands

Koerner

Burkepile

Fynn³

et al. 2014

Ecology

View full text Add to dashboard Cite

Abstract. Herbivory and fire shape plant community structure in grass-dominated ecosystems, but these disturbance regimes are being altered around the world. To assess the consequences of such alterations, we excluded large herbivores for seven years from mesic savanna grasslands sites burned at different frequencies in North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruger National Park). We hypothesized that the removal of a single grass-feeding herbivore from Konza would decrease plant community richness and shift community composition due to increased dominance by grasses. Similarly, we expected grass dominance to increase at Kruger when removing large herbivores, but because large herbivores are more diverse, targeting both grasses and forbs, at this study site, the changes due to herbivore removal would be muted. After seven years of largeherbivore exclusion, richness strongly decreased and community composition changed at Konza, whereas little change was evident at Kruger. We found that this divergence in response was largely due to differences in the traits and numbers of dominant grasses between the study sites rather than the predicted differences in herbivore assemblages. Thus, the diversity of large herbivores lost may be less important in determining plant community dynamics than the functional traits of the grasses that dominate mesic, disturbance-maintained savanna grasslands.

show abstract

“…Experimental exclosures (sensu Wagg, 1964) have been widely used as treatments to exclude (or statistically control for) the effects of predators, large herbivores, livestock, small mammals or birds on the species richness and recruitment in plant communities (Fraser and Madson, 2008;Jacobs and Naiman, 2008;Levick and Rogers, 2008;Negussie et al, 2008;Olofsson et al, 2008;Shitzer et al, 2008), on the abundance of other animals (Isaksson et al, 2007;Torre et al, 2007;Aerts et al, 2008;Huntzinger et al, 2008) and on processes such as sediment deposition, litter production, soil carbon sequestration and woody plant invasions (Descheemaeker et al, 2006a;2006b;Pei et al, 2008;Shrestha and Stahl, 2008;Yanoff and Muldavin, 2008).…”

mentioning

confidence: 99%

On the difference between “exclosures” and “enclosures” in ecology and the environment

Aerts

Nyssen

Haile

2009

Journal of Arid Environments

View full text Add to dashboard Cite

Large African herbivores decrease herbaceous plant biomass while increasing plant species richness in a semi-arid savanna toposequence

Cited by 50 publications

References 40 publications

Why is the world green? The interactions of top–down and bottom–up processes in terrestrial vegetation ecology

Why is the world green? The interactions of top–down and bottom–up processes in terrestrial vegetation ecology

Plant community response to loss of large herbivores differs between North American and South African savanna grasslands

On the difference between “exclosures” and “enclosures” in ecology and the environment

Contact Info

Product

Resources

About