Tree species diversity, composition and structure across human impacted and non-impacted areas in upgraded Marang’ Forest, Northern Tanzania

Paper Details

Research Paper 01/11/2021
Views (469) Download (57)

Tree species diversity, composition and structure across human impacted and non-impacted areas in upgraded Marang’ Forest, Northern Tanzania

Grace Nchimbi, Francis Moyo, Anna C. Treydte
J. Bio. Env. Sci.19( 5), 50-64, November 2021.
Certificate: JBES 2021 [Generate Certificate]


Globally, forests’ capacity to provide ecological services and support human life is rapidly declining due to the lack of deployment of proper resource management approaches. Countries adopt a wide range of management regimes that vary in degree of effectiveness in controlling unstainable human activities. This study aimed at understanding the impacts of upgrading the protection status of forested areas to a higher International Union for Conservation of Nature (IUCN) categories on tree species diversity, composition, and structure. The study explored Marang’ Forest (MF), annexed into Lake Manyara National Park a decade ago after being strongly impacted by mining and other human activities. It uses concentric circular plots to identify tree species, count stems, measure tree diameter at breast height, and assess indicators of disturbances in human-impacted and non-impacted areas. Results show a lower degree of human disturbances, including wood extraction, mining, livestock grazing, and trespassing has deterred in the forest. Tree species richness was about one third, and the Shannon’s diversity index was 17% higher, in impacted than non-impacted areas (t = 5.03, df = 34, P <0.001 and t = 4.98, df = 34, P < 0.001, respectively). The average number of tree stems ha-1 was 640 ± 26 significantly higher in impacted areas than non-impacted areas (524 ± 22; t = 3.46, df = 34, P = 0.01). It shows that lowering human disturbances by upgrading forests reserve to higher protected status enhance forest recovery and improve tree species diversity, composition, and structure.


Abdo MTV, Valeri SV, Ferraudo AS, Martins ALM, Spatti LR. 2017. Pioneer tree responses to variation of soil attributes in a tropical semi-deciduous forest in Brazil. Journal of Sustainable Forestry 36, 134-147.

Akida A, Blomley R. 2008. Trends in forest ownership, forest resources tenure and institutional arrangements: Are they contributing to better forest management and poverty reduction: Case study from the United Republic of Tanzania. Food and Agriculture Organization of the United Nations, Rome.

AWF. 2003. Lake Manyara watershed assessment. Progress Report.

Burgess ND, Malugu I, Sumbi P, Kashindye A, Kijazi A, Tabor K, Mbilinyi B, Kashaigili J, Wright TM, Gereau RE. 2017. Two decades of change in state, pressure and conservation responses in the coastal forest biodiversity hotspot of Tanzania. Oryx 51, 77-86.

Calle A, Holl KD. 2019. Riparian forest recovery following a decade of cattle exclusion in the Colombian Andes. Forest Ecology and Management 452, 117563.

Chazdon RL. 2003. Tropical forest recovery: legacies of human impact and natural disturbances. Perspectives in Plant Ecology, evolution and systematics 6, 51-71.

Chazdon RL, Guariguata MR. 2016. Natural regeneration as a tool for large‐scale forest restoration in the tropics: prospects and challenges. Biotropica 48, 716-730.

Chhetri NBK, Shrestha KK. 2019. Floristic diversity and important value indices of tree species in lower Kanchenjunga Singhalila ridge Eastern Nepal. American Journal of Plant Sciences 10, 248-263.

Chowdhury MA, Islam KN, Hafiz N, Islam K. 2019. Diversity of trees in a community managed forest: The case of Komolchori VCF, Khagrachari, Bangladesh. Geology, Ecology, and Landscapes 3, 95-103.

Cochran WG, William G. 1977. Sampling Techniques. John Wiley & Sons, Inc., New York.

Dharani N. 2011. Field guide to common trees & shrubs of East Africa. South Penguin Random House, South Africa.

Garcin Y, Deschamps P, Ménot G, De Saulieu G, Schefuß E, Sebag D, Dupont LM, Oslisly R, Brademann B, Mbusnum KG. 2018. Early anthropogenic impact on Western Central African rainforests 2,600 y ago. Proceedings of the National Academy of Sciences 115, 3261-3266.

Gebeyehu G, Soromessa T, Bekele T, Teketay D. 2019. Species composition, stand structure, and regeneration status of tree species in dry Afromontane forests of Awi Zone, northwestern Ethiopia. Ecosystem Health and Sustainability 5, 199-215.

Gizachew B, Rizzi J, Shirima DD, Zahabu E. 2020. Deforestation and connectivity among protected areas of Tanzania. Forests 11, 170.

Graham R. 1960. Flora of Tropical East Africa. Rosaceae. In Flora of Tropical East Africa. C Hubrard and E Milne-Redhead (Eds.). Kew: Royal Botanic Gardens.

Heino M, Kummu M, Makkonen M, Mulligan M, Verburg PH, Jalava M, Räsänen TA. 2015. Forest Loss in Protected Areas and Intact Forest Landscapes: A Global Analysis. PLOS ONE 10, e0138918.

IUCN. 2020. IUCN Policy Statement on Primary Forests Including Intact Forest Landscapes.

Kabede B, Soromessa T, Kelbessa E. 2014. Structure and regeneration status of Gedo dry evergreen montane forest, west Shewa zone of Oromia national regional state, central Ethiopia. Science, Technology and Arts Research Journal 3, 119-131.

Kent M, Coker P. 1992. Vegetation description and analysis, a practical approach. New York: John Wiley & Sons.

Khaine I, Woo SY, Kang H, Kwak M, Je SM, You H, Lee T, Jang J, Lee HK, Lee E. 2017. Species diversity, stand structure, and species distribution across a precipitation gradient in tropical forests in Myanmar. Forests 8, 282.

Kiffner C, Rheault H, Miller E, Scheetz T, Enriquez V, Swafford R, Kioko J, Prins HH. 2017. Long‐term population dynamics in a multi‐species assemblage of large herbivores in East Africa. Ecosphere 8, e02027.

Kikoti IA, Mligo C. 2015. Impacts of livestock grazing on plant species composition in montane forests on the northern slope of Mount Kilimanjaro, Tanzania. International Journal of Biodiversity Science, Ecosystem Services & Management 11, 114-127.

Kokwaro JO. 1986. Flora of Tropical East Africa – Anacardiaceae. Taylor & Francis.

Lejju JB. 2004. Ecological recovery of an Afromontane forest in south- western Uganda. African Journal of Ecology 42, 64-69.

Lukumbuzya K, Sianga C. 2017. Overview of the timber trade in East and Southern Africa: National Perspective and Regional Trade Linkages. TRAFFIC and WWF, Cambridge UK.

Luoga EJ, Witkowski ETF, Balkwill K. 2004. Regeneration by coppicing (resprouting) of Miombo (African savanna) trees in relation to land use. Forest Ecology and Management 189, 23-35.

Makero JS, Kashaigili JJ. 2016. Analysis of Land-Cover Changes and Anthropogenic Activities in Itigi Thicket, Tanzania. Advances in Remote Sensing 5, 269-283.

Mandallaz D. 2008. Sampling Techniques for Forest Inventories. Chapman & Hall/ CRC Taylor & Francis Group.

Mligo C. 2018. The plant species composition, diversity and natural regeneration of indigenous trees in the disturbed Ruvu South Forest Reserve, Tanzania. Tanzania Journal of Science 44, 46-60.

MNRT. 2006. Eastern Arc Mountains Strategy: Coding Forest Reserves as Protected Areas. Compiled by Conservation and Management of the Eastern Arc Mountain Forests, Forestry and Beekeeping Division, Morogoro, Dar es Salaam, Tanzania.

MNRT. 2020. Speech by the Minister of Natural Resources and Tourism during the Parliament session of the financial year 2019/2020. Dar es Salaam, Tanzania: Ministry of Natural Resources and Tourism.

Mwakosya J, Mligo C. 2014. The impacts of anthropogenic activities on the vegetation communities and structure in the western part of Rungwe forest reserve, Tanzania. Tanzania Journal of Science 40, 58-69.

Ndangalasi HJ, Mligo C, Mvungi E. 2014. Composition and size class structure of tree species in Ihang’ana forest reserve, Mufindi District, Tanzania. Tanzania Journal of Science 40, 1-2.

Ndemwike J. 2010. Life in Tanzania today and since the sixties. Continental Press, Dar es Salaam.

Pfeifer M, Burgess ND, Swetnam RD, Platts PJ, Willcock S, Marchant R. 2012. Protected areas: mixed success in conserving East Africa’s evergreen forests. PloS one 7, e39337.

Pringle RM. 2017. Upgrading protected areas to conserve wild biodiversity. Nature 546, 91-99.

Rejmánek M, Brewer SW. 2001. Vegetative Identification of Tropical Woody Plants: State of the Art and Annotated Bibliography 1. Biotropica 33, 214-228.

Riggio J, Jacobson AP, Hijmans RJ, Caro T. 2019. How effective are the protected areas of East Africa? Global ecology and conservation 17, e00573.

Rosa I, Rentsch D, Hopcraft JGC. 2018. Evaluating forest protection strategies: A comparison of land-use systems to preventing forest loss in Tanzania. Sustainability 10, 4476.

Santos S. 2017. Tanzania’s Nature Reserves. The Arc Journal 30, 1-32.

Simpson EH. 1949. Measurement of diversity. Nature 163, 688-688.

TANAPA. 2014. Lake Manyara National Park general management plan 2014—2024. TANAPA Publishing Unit.

UNEP-WCMC, IUCN. 2016. Protected Planet Report. UNEP-WCMC and IUCN, Cambridge UK and Gland, Switzerland.

URT. 2002. The Forest Act. No. 14 United Republic of Tanzania, Dar es Salaam, Tanzania.

URT. 2014. Fifth national report on the implementation of the Convention on Biological Diversity. No. Issue 1. Dar es Salaam, Tanzania: The Vice President’s Office, Division of Environment.

Vesa L, Malimbwi R, Tomppo E, Zahabu E, Maliondo S, Chamuya N, Nsokko E, Otieno J, Dalsgaard S. 2010. A national forestry resources monitoring and assessment of Tanzania (NAFORMA). FAO-Finland Forestry Programme Forestry Department.

Wekesa C, Kirui BK, Maranga E, Muturi GM. 2019. Variations in forest structure, tree species diversity and above-ground biomass in edges to interior cores of fragmented forest patches of Taita Hills, Kenya. Forest Ecology and Management 440, 48-60.

West PW. 2015. Tree and forest measurement. India: Springer.

World Conservation Monitoring Centre. 1998. Prunus africana. The IUCN Red List of Threatened Species. No. E.T33631A9799059.

Zilliox C, Gosselin F. 2014. Tree species diversity and abundance as indicators of understory diversity in French mountain forests: Variations of the relationship in geographical and ecological space. Forest Ecology and Management 321, 105-116.