Termite assemblage structure on Grazing lands in Semi-arid Nakasongola

Abstract

Termites are regarded as the primary cause of vegetation denudation in semi-arid Nakasongola, Uganda. Despite their damage to ecosystem functioning, there have been little efforts devoted to the description of the termite assemblage structure in the area. The study therefore intended to describe the termite assemblage structure with the intension to develop sustainable termite management strategies. The survey yielded 16 termite species from eight genera, three sub-families and one family. Species from the sub-family Macrotermitinae constituted 69% of the total number of species sampled. Members from the genus Macrotermes were the dominant species and constituted 38% of the total number of species sampled. The assemblage comprised of two feeding groups namely Group II and Group IV, with most of the species belonging to Group II. Most of the species were noted to nest in epigeal and hypogeal nests with a few species nesting in wood. Vegetation cover categories were noted to influence species richness. Highest species richness (14 species) occurred in sparse vegetation category followed by dense category (11) and the least (8 species) occurring on bare ground. The termite assemblage of Nakasongola was dominated by Macrotermes species which largely forage on litter and nest in epigeal mounds.

Magnitude of the termite problem and its potential anthropogenic causes in Nakasongola district of Uganda

“…The density of mounds has increased markedly over recent years, reaching an average of 227 ha −1 (Mugerwa et al . ). This value is 26% higher than the average value (180 ha −1 ) of mounds (both large and small) in Uganda reported previously (Okwakol and Sekamatte ) and is 12 times higher than the highest density (18.5 ha −1 ) of mounds reported in Uganda in 1977 (Pomeroy ).…”

“…The literature suggests that T. oeconomus is not the species devastating herbaceous vegetation, and that the generalist feeders are responsible for the observed damage to herbaceous plants (Mugerwa et al . ).…”

“…Several studies have identified reduction in degradable detrital mass and loss of the natural enemies of termites as the principal factors contributing to the escalating devastation of herbaceous vegetation by subterranean termites in the grasslands of Nakasongola (Sekamatte ; Mugerwa et al . ,b,c). The termite assemblage in the area is dominated by members of the sub‐family Macrotermitinae, within which species of Macrotermes are, by far, the most abundant.…”

“…The most obvious indication of termite problem to farmers on the grasslands of Nakasongola is the presence of numerous conspicuous mounds, which can occupy up to 75% of the area of their ranches (Sekamatte 2001b;Mugerwa et al 2011b). The density of mounds has increased markedly over recent years, reaching an average of 227 ha À1 (Mugerwa et al 2011a). This value is 26% higher than the average value (180 ha À1 ) of mounds (both large and small) in Uganda reported previously and is 12 times higher than the highest density (18.5 ha À1 ) of mounds reported in Uganda in 1977 (Pomeroy 1977).…”

Application of distance–decay models for inferences about termite mound-induced patterns in dryland ecosystems

“…This can weaken the grass cover or slow down the recovery of the vegetation. This may also exacerbate the competition between livestock and termites as noted in the semi-arid rangelands of Uganda (Mugerwa et al, 2011;Sileshi et al, 2009) and Ethiopia (Wood, 1991). In many rangelands, bush encroachment has also become a serious problem.…”