Elephant both Increase and Decrease Availability of Browse Resources for Black Rhinoceros

Landman, Marietjie; Kerley, Graham I. H.

doi:10.1111/btp.12066

Cited by 19 publications

(17 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Structural engineering describes the creation of physical structures by engineer species (Berke, ), essentially changing the complexity of plant and soil habitats (Landman & Kerley, ). The impacts of engineer functions on habitat structures and shelter availability were among the most‐observed engineer interactions (Appendix S2).…”

Section: What Are the Impacts Of Ecosystem Engineers In Terrestrial Hmentioning

confidence: 99%

A global database and “state of the field” review of research into ecosystem engineering by land animals

Coggan

Hayward

Gibb

2018

Journal of Animal Ecology

118

View full text Add to dashboard Cite

Ecosystem engineers have been widely studied for terrestrial systems, but global trends in research encompassing the range of taxa and functions have not previously been synthesised. We reviewed contemporary understanding of engineer fauna in terrestrial habitats and assessed the methods used to document patterns and processes, asking: (a) which species act as ecosystem engineers and with whom do they interact? (b) What are the impacts of ecosystem engineers in terrestrial habitats and how are they distributed? (c) What are the primary methods used to examine engineer effects and how have these developed over time? We considered the strengths, weaknesses and gaps in knowledge related to each of these questions and suggested a conceptual framework to delineate "significant impacts" of engineering interactions for all terrestrial animals. We collected peer-reviewed publications examining ecosystem engineer impacts and created a database of engineer species to assess experimental approaches and any additional covariates that influenced the magnitude of engineer impacts. One hundred and twenty-two species from 28 orders were identified as ecosystem engineers, performing five ecological functions. Burrowing mammals were the most researched group (27%). Half of all studies occurred in dry/arid habitats. Mensurative studies comparing sites with and without engineers (80%) were more common than manipulative studies (20%). These provided a broad framework for predicting engineer impacts upon abundance and species diversity. However, the roles of confounding factors, processes driving these patterns and the consequences of experimentally adjusting variables, such as engineer density, have been neglected. True spatial and temporal replication has also been limited, particularly for emerging studies of engineer reintroductions. Climate change and habitat modification will challenge the roles that engineers play in regulating ecosystems, and these will become important avenues for future research. We recommend future studies include simulation of engineer effects and experimental manipulation of engineer densities to determine the potential for ecological cascades through trophic and engineering pathways due to functional decline. We also recommend improving knowledge of long-term engineering effects and replication of engineer reintroductions across landscapes to better understand how large-scale ecological gradients alter the magnitude of engineering impacts.

show abstract

Section: What Are the Impacts Of Ecosystem Engineers In Terrestrial Hmentioning

confidence: 99%

A global database and “state of the field” review of research into ecosystem engineering by land animals

Coggan

Hayward

Gibb

2018

Journal of Animal Ecology

118

View full text Add to dashboard Cite

show abstract

“…Elephant modification of vegetation, including alterations to canopy height, can facilitate access to forage by browsers (Valeix et al. , Landman and Kerley ) and create habitat for small vertebrates (Pringle ), for example. In addition, opening up of vegetation by elephants influences visibility for other species, likely favoring prey species by aiding earlier predator detection (Valeix et al.…”

Section: Discussionmentioning

confidence: 99%

“…However, browser facilitation and the generation of spatial heterogeneity caused by elephants can be replaced with competition for forage and thicket transformation when elephant densities increase dramatically, negatively affecting other herbivore species and ecosystem processes (Valeix et al. , Landman and Kerley ). Moreover, the height reductions caused by elephants were massive (up to fourfold) and more likely to remove potential habitat for other species than create it.…”

Section: Discussionmentioning

confidence: 99%

“…This microclimate is provided by the dense vegetation, and changes when the surrounding thicket density is altered either vertically or horizontally, as occurs with heavy browsing (Moolman and Cowling , Kerley and Landman ). Elephant foraging can also both limit and facilitate browse availability for other herbivores, including the endangered black rhinoceros, Diceros bicornis , by removing forage while simultaneously opening up pathways that facilitate access to new browse, leading to further impacts by other herbivores, primarily in the lower strata of the vegetation (Landman and Kerley ). Furthermore, horizontal changes in vegetation distribution caused by elephants breaking up thicket clumps has led to concerns about landscape homogenization, especially in areas of concentrated foraging (Landman et al.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Megafaunal effects on vegetation structure throughout a densely wooded African landscape

Davies

Gaylard

Asner

2018

Ecological Applications

View full text Add to dashboard Cite

Megafauna strongly affect vegetation structure and composition, often leading to management concern. However, the extent of their influence across large scales and varying ecosystems remains largely unknown. Using high resolution airborne Light Detection and Ranging (LiDAR), we investigated landscape-scale changes in vegetation height and three-dimensional (3D) structure across landscapes of varying elephant densities and presence over time, and in response to surface water distribution and terrain variability in the heavily managed thicket biome of the Addo Elephant National Park, South Africa. Elephants caused up to a fourfold reduction in vegetation height and altered the vertical profile, but increased vegetation height variability. Vegetation height also increased with elevation and distance from water, particularly in areas that elephants had long occupied at high densities. Slope had opposing effects on vegetation height, with height increasing with slope in areas long exposed to elephants, but decreasing where elephants had only recently been granted access. Our results suggest that elephants are the primary agents of vegetation change in this ecosystem, but that the strength of their effects varies across the landscape, enabling management to use water and terrain as mitigation tools. We further highlight the necessity of landscape-level experimental studies on megafaunal effects to untangle mechanisms and establish causality.

show abstract

“…Elephants have a range of effects in savanna ecosystems ranging from positive, (e.g., dispersal of seeds, facilitation of feeding by other herbivores, Rutina, Moe & Swenson, ; Young, Palmer & Gadd, ; Pringle, ; Nasseri, McBrayer & Schulte, ) to negative, for example, limiting tree survival and recruitment and decreasing woody densities, as well as simplification of vegetation structure, which decreases habitat for other fauna (Cumming et al., ; Dublin, Sinclair & McGlade, ; Landman & Kerley, ; McCauley, Keesing, Young, Allan & Pringle, ; McCleery et al., ). Elephants can cause significant tree mortality through different mechanisms including ringbarking and pollarding (Coetzee, Engelbrecht, Joubert & Retief, ; Gadd, ; Helm, Wilson, Midgley, Kruger & Witkowski, ; Helm, Witkowski, Kruger, Hofmeyr & Owen‐Smith, ; Midgley, Lawes & Chamaillé‐Jammes, ; Moncrieff, Kruger & Midgley, ; O'Connor, Goodman & Clegg, ; Shannon et al., ; Vanak et al., ).…”

Section: Introductionmentioning

confidence: 99%

Ants, fire, and bark traits affect how African savanna trees recover following damage

et al. 2019

View full text Add to dashboard Cite

Bark damage resulting from elephant feeding is common in African savanna trees with subsequent interactions with fire, insects, and other pathogens often resulting in tree mortality. Yet, surprisingly little is known about how savanna trees respond to bark damage. We addressed this by investigating how the inner bark of marula (Sclerocarya birrea), a widespread tree species favoured by elephants, recovers after bark damage. We used a long‐term fire experiment in the Kruger National Park to measure bark recovery with and without fire. At 24 months post‐damage, mean wound closure was 98, 92, and 72%, respectively, in annual and biennial burns and fire‐exclusion treatments. Fire exclusion resulted in higher rates of ant colonization of bark wounds, and such ant colonization resulted in significantly lower bark recovery. We also investigated how ten common savanna tree species respond to bark damage and tested for relationships between bark damage, bark recovery, and bark traits while accounting for phylogeny. We found phylogenetic signal in bark dry matter content, bark N and bark P, but not in bark thickness. Bark recovery and damage was highest in species which had thick moist inner bark and low wood densities (Anacardiaceae), intermediate in species which had moderate inner bark thickness and wood densities (Fabaceae) and lowest in species which had thin inner bark and high wood densities (Combretaceae). Elephants prefer species with thick, moist inner bark, traits that also appear to result in faster recovery rates.

show abstract

Elephant both Increase and Decrease Availability of Browse Resources for Black Rhinoceros

Cited by 19 publications

References 48 publications

A global database and “state of the field” review of research into ecosystem engineering by land animals

A global database and “state of the field” review of research into ecosystem engineering by land animals

Megafaunal effects on vegetation structure throughout a densely wooded African landscape

Ants, fire, and bark traits affect how African savanna trees recover following damage

Contact Info

Product

Resources

About