Ecological and human impacts on stand density and distribution of tamarind (Tamarindus indica L.) in Senegal

Abstract

Indigenous fruit tree species such as tamarind (Tamarindus indica L.) in African sub-Saharan traditionally act to build resilience into the farming system in terms of food security, income generation and ecosystem stability. Therefore, increasing our knowledge on their ecology and distribution is a priority. Tamarind is mainly grown for the fruits but is also a valuable timber species. The fruit pulp has a high content of vitamin B and is eaten fresh or made into jam, chutney, juice or sweets. Flowers, leaves and seeds are also edible and used in a variety of dishes. The main objective of this study is to evaluate actual density of tamarind in Senegal and the climate change effects on its distribution for better conservation strategies. Tamarind's distribution and density around villages were recorded and modelled in different agro-ecological zones in Senegal using transect method and under current and future climates. Distribution under two future climate scenarios were modelled using four climate models and three time slices (2020, 2050 and 2080). Results show a decreasing gradient in tree density (from 7 to 1 trees km-2) from the Sudano agro-ecological zone (in the south) to the Sahel (in the north). Future climate predictions show that although tamarind distribution will increase in the north-west and south of the country in 2020; by 2050, the area identified as suitable for its growth will be greatly reduced. Areas in the north-west basin appear to be an important refugia for the species under future climate conditions. However, density around villages in this area was found to be relatively low indicating that this could lead to problems of poor connectivity and inbreeding depression. This region should therefore be highlighted as important conservative management and protection strategies of tamarind in this region

Distribution, biomass and local importance of tamarind trees in south-western Madagascar

“…The variation of tamarind density between the coastal and plateau zone in the Mahafaly region may be mostly attributed to differences in the amount of annual rainfall, which is higher on the plateau and results in higher tree densities. Similar results were found in Senegal (Bourou et al, 2012) and in Benin (Fandohan et al, 2011b). Tamarinds have a minimum annual rainfall requirement of 250 mm year −1 with a particular adaptation to drought periods and grow well at 500-1500 mm (El-Siddig et al, 2006;Van-den-Bilcke et al, 2013), where regeneration and growth rates of trees are higher (Fandohan et al, 2011b;Mertl-Millhollen et al, 2011).…”

Prioritization of useful medicinal tree species for conservation in Wari-Maro Forest Reserve in Benin: A multivariate analysis approach

“…These species' adult trees are habitually conserved by local people because of their numerous food, medicinal and other uses (Sibibé and Williams, 2002; Fandohan et al, 2010;Bourou et al, 2012). The most important factors that may have a negative impact on these species are human practices that result in the harvesting of fruits and leaves in combination with climate change (Bourou et al, 2012;Sanou et al, 2014). Concerning S. longipedunculata, no other use was reported apart from the medicinal use for which their roots were sold expensively at 140.80 US$/kg with a small bulk offered for sale daily (34 kg) on the market in Southern Benin (Quiroz et al, 2014).…”

“…This could be the case for A. digitata, T. indica, and S. longipedunculata. Indeed, it has been proven that human disturbance is not the sole causal factor driving the decline of T. indica and A. digitata populations (Fandohan et al, 2010;Bourou et al, 2012;Ouédraogo and Thiombiano, 2012). These species' adult trees are habitually conserved by local people because of their numerous food, medicinal and other uses (Sibibé and Williams, 2002; Fandohan et al, 2010;Bourou et al, 2012).…”

“…Indeed, it has been proven that human disturbance is not the sole causal factor driving the decline of T. indica and A. digitata populations (Fandohan et al, 2010;Bourou et al, 2012;Ouédraogo and Thiombiano, 2012). These species' adult trees are habitually conserved by local people because of their numerous food, medicinal and other uses (Sibibé and Williams, 2002; Fandohan et al, 2010;Bourou et al, 2012). The most important factors that may have a negative impact on these species are human practices that result in the harvesting of fruits and leaves in combination with climate change (Bourou et al, 2012;Sanou et al, 2014).…”

Global to local sustainability

“…Parklands also play an important role in preserving ecological sustainability (Boffa, 1999). They are progressively becoming important because they provide ecological services that make the ecosystem resilient and tolerant to extreme environmental conditions (Dawson et al, 2011) under increasing temperatures (Boko et al, 2007;Christensen et al, 2007) and varying amounts of rainfall (Christensen et al, 2007;Meehl et al, 2007) as determined by climate change models for the region which is subjected to drought stress and human pressure (Bourou et al, 2012).…”