The effect of soil physical properties and soil microclimate on rodent burrows’ abundance and their characteristics in Western Usambara Mountains, Tanzania
ournal of Agriculture and Ecology Research International
Abstract
The present study was carried out between September 2009 and June 2013 in Western Usambara
Mountains plague focus with the aim of establishing the influence of selected soil physical
properties and soil microclimate on rodent burrows’ abundance, portal orientation and use. Two
landscapes with high and medium plague frequencies in Lokome and Lukozi villages were studied.
In the two landscapes data were collected from 117 and 200 observation sites respectively, using
100 m x 200 m quadrats. At each quadrat crossing, a sample quadrat of 20 m x 20 m was
demarcated for scanning rodent burrows whereby burrows encountered were counted and their
portal orientation and burrow use described. Within each sample quadrat, selected soil physical
properties including thickness of the soil genetic horizons and soil dry consistence were
determined. Soil samples were collected from each horizon for laboratory texture analysis.
Temperature (surface and subsurface to a depth 10 cm) and relative humidity at a depth of 10 and
30 cm were collected using infrared, thermo-couple thermometers and i-Buttons. Descriptive
statistics, ANOVA and logistic regression were used to analyse the data by R-software. There were
significant (P=.0001) differences between the two landscapes regarding topsoil depth, infrared
temperature, relative humidity and rodent burrows’ abundance. In the high plague frequency
landscape there was a significant influence (P=.05) of topsoil horizon thickness on rodent burrows’
abundance and use. Results also indicate that soil temperature to a depth of 10 cm was
significantly (P=.05) correlated with rodent burrow use. Likewise, in the medium plague frequency
landscape, soil physical properties and soil microclimate significantly (P=.0001) discouraged rodent
burrowing. It was concluded that soil physical and soil microclimate encouraged and discouraged
burrowing in the high and the medium plague frequency landscapes, respectively. The landscape
with high rodent burrows’ abundance corresponded with high plague frequency records