C. Consalvo 1 , L. Belelli Marchesini 1 , R. Valentini 1

1. Error bars: standard deviation Dashed line: nonlinear regression Error bars: standard deviation Dashed line: nonlinear regression UNIVERSITY OF TUSCIA UNIVERSITY OF CAPE COAST DepartmentofForestEnvironment and Resources Dipartimento di Scienze dell’Ambiente Forestale e delle sue Risorse Analysis of biodiversity and biomass in the Ankasa Resource Reserve, Ghana C. Consalvo1, L. Belelli Marchesini1, R. Valentini1 1 Department of Forest Science and resources (DISAFRI), University of Tuscia - Viterbo, ITALY Aim Tropical rainforests play a crucial role for the biosphere and therefore are a natural reserves of biological diversity and store large amounts of carbon playing a major role in the global carbon budget. This study was conducted in the framework of CarboAfrica project, and was aimed at the ecological characterization of the Ankasa tropical forest. Materials and methods Two transects were demarcated for a total surface of 2 ha. The height of the tree was estimated with Vertex laser V 1.6 or with a visual estimation. The diameter of the trees was taken at 1.30 m above the ground. All the plants with diameter over 5 cm were measured in every subplot. • Into the sampling area, the following issues were analyzed: • Biodiversity - Several biodiversity indices were calculated, including the Genetic Heat Index (GHI)[1] for estimating the abundance of rare species in the forest population. • Leaf area index (LAI) - the LAI was estimated by hemispherical photo process. Photos were taken with a Nikon D200 camera (Fig. 1) and with a lens Nikkor fisheye 10.5 mm every 10 m. The imageswereprocessedwith the software CAN-EYE devlopedby INRA-CSE, Avignon, France. • Biomass - the aboveground biomass was estimated using an allometric equation developed for the Wet Evergreen Forests: The Ankasa Resource Reserve The Ankasa Conservation Area lies in Southwest Ghana on the border with the Ivory Coast. It covers 509 km2 and includes the Nini-Suhien National Park (166 km2) and the Ankasa Resource Reserve (343 km2), as shown in figure 1. Ankasa represents the most biodiverse rain forest in Ghana and unlike the Nini-Suhien National Park is not fully protected. The climate of the area is characterized by a distinctive bi-modal rainfall pattern occurring from April to July and September to November. The average annual rainfall is 1700 to 2000mm. Mean monthly temperatures are typical of tropical lowland forest and range from 24°C to 28°C. Relative humidity is generally high throughout the year, being about 90% during the night falling to 75% in early afternoon. Fig 1 -Measuring LAI by hemispherical photo technique. Biomass = exp [-3,3012+0,9439 ln (D2H)] Biomass=standing dry biomass (kg) D=diameter (cm) H=height (m) Results Along the sampling area of 2 ha, 38 families, 114 genera and 184 species were found. A total of 1898 plants with a diameter at breast height >5 cm was found with an average density per hectare of 950 plants. The species were listed into a different categories (Fig. 2). This encapsulates the most of the ‘ecological niche’ of the overall species. • Fig 2 - Distribution of the number of plants in the different categories of temperament. • Pioneers are generally species that benefit from forest disturbance. • NPLDs are ‘Non pioneer light demanders’, being intermediate between the previous and next categories. • Shade-bearers are often to be found healthy in the shady understorey, and rarely benefit from disturbance • Swamp species are largely restricted to rivers and/or swamps. The basal area per hectare was estimated as 50 ± 11,5 m2 ha-1(average ± dev.st.). The aboveground biomass was 271 t ha-1 which equals to a carbon stock of 135 t C ha-1 after applying a conversion factor of 0,47 gC/g d.m. Biomass H = 28,6 *(1-0,97d) R2 = 0,98 Error bars: standard deviation Dashed line: nonlinear regression The poor attendance rate of secondary and pioneer species indicates that the disturbance in this forest has been very limited and is confined to small areas. The high biodiversity that characterizes Ankasa forest is remarked by the GHI which resulted in 197, within the sampling area. The percentage distribution of species according to the index of rarity is shown in Fig. 3 Fig 5 - Distribution of biomass and number of plants in various classes of diameter. The plants included in the intermediate diameter classes are those that have a greater development in height and providing a significant contribution to the total biomass. Fig 4 – Ipsometric curve. The structure of the Ankasa Forest consists of large diameter trees but with reduced stature with plants that rarely exceed 40 meters in height. • Fig 3 - Star ratings for biodiversity conservation. • Black: urgent attention to conservation of populations needed. Rare internationally and not common in Ghana. • Gold: fairly rare internationally and/or locally. • Blue: widespread internationally but rare in Ghana, or vice-versa. • Scarlet, red and pink: common but under pressure from exploitation. • Green: no conservation concern. • Others: species not yet considered The estimated LAI was 6 ± 1.01 (average +/-dev.st.). The maximum value of LAI in tropical forests varies from 4 to 7. Phenology in tropical forests is more related to the water balance rather than to changes in temperature and solar radiation. In comparison to other regions, the variation of these two variables during the year is reduced. Fig 6 - LAI values estimated in the sub plots along the transects. Conlusion Due to the low level of secondary and pioneer species and the high rate of biodiversity, Ankasa reserve can be considered an undisturbed forest. Ankasa is also an important carbon stocks estimated at 135 t C ha-1 in stand biomass. In light of these results it is clear that the African tropical forests, yet undergoing an impressive rate of deforestation should be considered with great attention to avoiding the biodiversity loss, and mitigating climate change. References [1] Hawthorne, W., Grut, M., & Abu-Juam, M. (1998). Forest production and biodiversity conservation in Ghana, and proposed international support of biodiversity conservation. For more information: Dr. Luca Belelli Marchesini belelli@unitus.it University of Tuscia - Department of Forest Environment and Resources Via De Lellis, 01100 Viterbo- Italy phone ++39 0761 357394; fax ++39 0761 357389