Conservation - Scientific Papers

[Matias]

Two excellent documents.

The consequences of replacing wildlife with

 livestock in Africa

• Gareth P. Hempson, 
• Sally Archibald & 
• William J. Bond 
  

Scientific Reports volume 7, Article number: 17196 (2017) 
Abstract

The extirpation of native wildlife species and widespread establishment of livestock farming has dramatically distorted large mammal herbivore communities across the globe. Ecological theory suggests that these shifts in the form and the intensity of herbivory have had substantial impacts on a range of ecosystem processes, but for most ecosystems it is impossible to quantify these changes accurately. We address these challenges using species-level biomass data from sub-Saharan Africa for both present day and reconstructed historical herbivore communities. Our analyses reveal pronounced herbivore biomass losses in wetter areas and substantial biomass increases and functional type turnover in arid regions. Fire prevalence is likely to have been altered over vast areas where grazer biomass has transitioned to above or below the threshold at which grass fuel reduction can suppress fire. Overall, shifts in the functional composition of herbivore communities promote an expansion of woody cover. Total herbivore methane emissions have more than doubled, but lateral nutrient diffusion capacity is below 5% of past levels. The release of fundamental ecological constraints on herbivore communities in arid regions appears to pose greater threats to ecosystem function than do biomass losses in mesic regions, where fire remains the major consumer.

Link: https://www.nature.com/articles/s41598-017-17348-4

Spiny plants, mammal browsers, and the 

origin of African savannas

Tristan Charles-Dominique, T. Jonathan Davies, Gareth P. Hempson, Bezeng S. Bezeng,  Barnabas H. Daru, Ronny M. Kabongo, 

Olivier Maurin, A. Muthama Muasya, Michelle van der Bank, and William J. Bond

PNAS September 20, 2016 113 (38) E5572-E5579; published ahead of print September 6, 2016 

Significance
Africa hosts contrasting communities of mammal browsers and is, thus, the ideal background for testing their effect on plant communities and evolution. In this study at the continental scale, we reveal which mammal browsers are most closely associated with spiny communities of trees. We then show a remarkable convergence between the evolutionary histories of these browsers (the bovids) and spiny plants. Over the last 16 My, plants from unrelated lineages developed spines 55 times. These convergent patterns of evolution suggest that the arrival and diversification of bovids in Africa changed the rules for persisting in woody communities. Contrary to our current understanding, our data suggest that browsers predate fire by millions of years as agents driving the origin of savannas.

Link: http://www.pnas.org/content/113/38/E5572 Reply