Final words, or a whisper

Two new studies appear in the recent journal Biological Conservation . The pieces cover unique species, numbering to close to 1000, within the Eastern Arc Mountains of Kenya and Tanzania. The are is rapidly coming under threat, yet has the greatest native concentrations of animals in Africa. These animals are found no place else on Earth. At least 832 plants, 43 butterflies, and 96 animals are only found here, this being the region where the highland mangabey was found recently (a new genus of monkey Rungwecebus) . Even more species remain unclassified, these numbers are upwards of 15 and include some new reptiles.

These surveys and analysis of threatened areas shed light on the plight of the regions, the species, and potentially the next monumental discovery in zoology. They can also be the grave markers for the future, the final words of the species, or the whispers of what we did not find in time.....

Craig Heinselman
Peterborough, NH

Biological Conservation Volume 134, Issue 2 , January 2007, Pages 209-231

The biological importance of the Eastern Arc Mountains of Tanzania and Kenya
N.D. Burgessa, T.M. Butynskid, N.J. Cordeiroe, N.H. Doggartg, J. Fjeldsåh, K.M. Howelli, F.B. Kilahamaa, S.P. Loaderk, J.C. Lovettl, B. Mbilinyia, M. Menegonm, D.C. Moyern, E. Nashandaj, A. Perking, F. Roverom, W.T. Stanleyo and S.N. Stuartp

The Eastern Arc Mountains are renown in Africa for high concentrations of endemic species of animals and plants. Thirteen separate mountain blocks comprise the Eastern Arc, supporting around 3300 km2 of sub-montane, montane and upper montane forest, less than 30% of the estimated original forested area. At least 96 vertebrate species are endemic, split as follows: 10 mammal, 19 bird, 29 reptile and 38 amphibian species. This includes four endemic or nearly endemic species of primate – the Sanje Mangabey, the Iringa Red Colobus, the Mountain Galago and the new Kipunji monkey that forms its own monotypic genus. A further 71 vertebrate species are near-endemic. At least 800 vascular plant species are endemic, almost 10% of these being trees. These endemics include the majority of the species of African violet – Saintpaulia, a well-known flowering plant in Western households. An additional 32 species of bryophytes are also endemic. Many hundreds of invertebrates are also likely to be endemic, with data for butterflies, millipedes and dragonflies indicating potential trends in importance. Seventy-one of the endemic or near-endemic vertebrates are threatened by extinction (8 critical, 27 endangered, 36 vulnerable), with an additional seven wide ranging threatened species. Hundreds of plant species are also threatened. Most Eastern Arc endemics are closed-forest specialists and comprise taxa with an ancient history and those of more recent origin, including some possessing ancient affinities with taxa from West Africa, Madagascar, and even South America and Southeast Asia. Mountain block prioritisation for biodiversity conservation shows that Udzungwas, East Usambaras and Ulugurus are the most important blocks, with other important blocks being the Ngurus and West Usambaras. Rankings are correlated closely with the area of remaining forest. Most of the remaining forest is found within nearly 150 Government Forest Reserves, with 106 of these managed nationally for water catchment, biodiversity and soil conservation and where forest exploitation is not allowed. Outside these areas most forest has been cleared, except in small village burial/sacred sites, a few Village Forest Reserves, and inaccessible areas. In most Eastern Arc Mountains the local populations have not encroached beyond the reserve boundaries to develop farms, but forest resources within the boundaries are used for fuel and building materials and some forests are heavily degraded. Fire is also a problem as it enters and destroys forests during the dry seasons. The future of the biodiversity on the Eastern Arc Mountains is closely tied to management policies and capacity of the Tanzania Forestry and Beekeeping Division, Tanzania National Parks Authority, and Kenya Forest Department. Supporting these agencies in their mandated job is an essential conservation investment over the longer term.

Biological Conservation Volume 134, Issue 2 , January 2007, Pages 164-177


Correlations among species distributions, human density and human infrastructure across the high biodiversity tropical mountains of Africa
Neil D. Burgessa, Andrew Balmfordc, Norbert J. Cordeirod, Jon Fjeldsåg, Wolfgang Küperh, Carsten Rahbeki, Eric W. Sandersonj, Jörn P.W. Scharlemannk, J. Henning Sommerh and Paul H. Williamsl

This paper explores whether spatial variation in the biodiversity values of vertebrates and plants (species richness, range-size rarity and number or proportion of IUCN Red Listed threatened species) of three African tropical mountain ranges (Eastern Arc, Albertine Rift and Cameroon-Nigeria mountains within the Biafran Forests and Highlands) co-vary with proxy measures of threat (human population density and human infrastructure). We find that species richness, range-size rarity, and threatened species scores are all significantly higher in these three tropical African mountain ranges than across the rest of sub-Saharan Africa. When compared with the rest of sub-Saharan Africa, human population density is only significantly higher in the Albertine Rift mountains, whereas human infrastructure is only significantly higher in the Albertine Rift and the Cameroon-Nigeria mountains. Statistically there are strong positive correlations between human density and species richness, endemism and density or proportion of threatened species across the three tropical African mountain ranges, and all of sub-Saharan Africa. Kendall partial rank-order correlation shows that across the African tropical mountains human population density, but not human infrastructure, best correlates with biodiversity values. This is not the case across all of sub-Saharan Africa where human density and human infrastructure both correlate almost equally well with biodiversity values. The primary conservation challenge in the African tropical mountains is a fairly dense and poor rural population that is reliant on farming for their livelihood. Conservation strategies have to address agricultural production and expansion, in some cases across the boundaries and into existing reserves. Strategies also have to maintain, or finalise, an adequate protected area network. Such strategies cannot be implemented in conflict with the local population, but have to find ways to provide benefits to the people living adjacent to the remaining forested areas, in return for their assistance in conserving the forest habitats, their biodiversity, and their ecosystem functions.