Abstract:
Heterogeneity in the landscapes of West Usambara Mountains on land use and human activities
has been reported. However, the interface of land use patterns and human modified soils with small
mammal and flea abundance for possible explanation of plague has not been explored. This study was
carried out to determine the link between anthropogenic soils and land use patterns on small mammal and
flea abundance and the occurrence of reported plague in the Western Usambara Mountains in Tanzania.
Standard soil survey methods were used to identify and describe soils and land use patterns on lower
slopes and valley bottoms on which the surrounding villages are reported to have high and medium plague
frequencies. The identified soils were characterised in terms of their morphological and physico-chemical
properties and classified according to FAO-World Reference Base for Soil Resources. Small mammals were
trapped on the same landscape positions and identified to genus/species level. Fleas were removed from
the trapped small mammals, counted and identified to species level. In total 57 small mammals were
captured from which 32 fleas were collected. Results show that human settlements and mixed cultivation
on lower slopes and continuous vegetable cropping in the valley bottoms are dominant land use types.
Intensive use of forest soils, manuring and irrigation on farms in the studied landscapes have contributed
to the development of uniquely human modified soils namely Hortic Anthrosols in the lower slopes and
Plaggic Irragric Hortic Anthrosols in valley bottoms. The identified anthropogenic soils and land use patterns
are associated with high abundance of small mammals (Mastomys natalensis) and flea species (Xenopsylla
brasiliensis and Dinopsyllus lypusus). This phenomenon is vividly apparent in the villages with medium to
high plague frequencies. The study suggests that plague surveillance programmes should consider the
existing relationship between anthropogenic soils, land use patterns, small mammal and flea abundance.
