Diversity, Population Structure and Regeneration Status of Woody Species in Dry Woodlands Adjacent to <i>Molapo</i> Farms in Northern Botswana

Abstract

The diversity, population structure and regeneration status of woody species were studied at Xobe and Shorobe Villages in northern Botswana. A total of 130 and 111 quadrats of 20 × 20 m size were laid down at 50 m intervals along parallel line transects at Xobe and Shorobe, respectively. A total of 46 woody species, 27 from Xobe and 41 from Shorobe were recorded. Of the 46 woody species, only 22 were recorded at both sites. Ten genera and six families were found only in Shorobe while one genus and one family were found only in Xobe. The diversity and evenness of woody species were 1.5 and 0.5 in Xobe, respectively, and 2.18 and 0.6 in Shorobe, respectively. The similarities of woody species in terms of richness of species, genera and families at the two sites were about 50%, 54% and 56%, respectively. The mean densities of woody species were 2745.7 ± 1.35 and 4269.7 ± 36 individuals ha −1 at Xobe and Shorobe, respectively. Despite differences in absolute numbers, the total mean densities of woody species at both sites did not exhibit significant (P = 0.35) differences. At both sites, woody species were dominated by individuals of only a few species, which also exhibited the highest values of important value index. The population structure patterns of the woody species were categorized into five groups. The species in the first group exhibited reverse J-shaped distribution, which indicates stable population structures. The species in the second group showed relatively good recruitment but the regeneration is negatively affected. The species in the other three groups exhibited hampered regeneration as a result of disturbances caused by humans, domestic animals and annual fires. The parameters assessed indicate the need for attention and appropriate management interventions by the relevant national authorities at various levels.

Ethnobotanical Survey of Woody Plants in Shorobe and Xobe Villages, Northwest Region of Botswana

“…The vegetation in Shorobe and Xobe is dominated by mophane (Colophospermum mopane (Benth.) Leonard) and mixed species of Acacia, respectively (DEA 2008, Neelo et al 2013). …”

“…The Xobe and Shorobe Villages form part of the settlements around the famous Okavango Delta in the northwestern Botswana. In these settlements, which are mainly dominated by subsistence farmers who rely mostly on flood recession (molapo) and dryland farming, woody species are very important and useful (Neelo et al 2013). The vegetation in this area is becoming so scarce that it is possible for some species to have been wiped out completely.…”

“…Trees growing in the open areas of this region contribute to the wide-ranging needs of the rural people. These trees are currently used by the local communities for multiple purposes, such as honey production, food, dye, fiber, fodder, medicines, fuelwood, building materials, fencing, and production of household utensils (Neelo et al 2013). Some of these trees have support roles for sustainable agriculture, livestock production, and hunting activities while others have cultural, religious, or judicial functions.…”

“…While the knowledge on the usefulness of these plants remains high, poor methods of exploitation, agriculture, and over-exploitation are putting most species under pressure of local extermination (Neelo et al 2013). Ethnobotanical studies have reported useful plant species in Botswana (Babitseng & Teketay 2013, Legwaila et al 2011, Neudeck et al 2012 and other neighboring countries (Chinemana et al 1995, Hutchings & van Staden 1994 and Africa as a whole (Abebe & Hagos 1991, Holdings & Njuguna 2001, Teketay et al 2010, but ethnobotanical surveys on the uses of plants are scanty in Botswana.…”

“…Soils in molapo fields are classified as young alluvial soils. Texture varies from clayey (35% to 60% clay), especially in low-lying areas, through fine loamy (18% to 35% clay) to coarse loamy (< 18% clay) (Chimbari et al 2009, Neelo et al 2013. Flooding of most molapo fields had not occurred for several years until flood waters returned in 2009.…”