Assessing land degradation in the Monduli District, northern Tanzania

Abstract

One of the many contentious issues facing the appropriate and accurate assessment of land degradation is the varying emphasis placed on vegetation degradation and soil degradation processes. This has led to the compartmentalization of land degradation assessment methods, depending on the particular perspective adopted. The land degradation assessment method presented here attempts to take into account both vegetation and soil degradation. This methodology is applied to the southern part of the Monduli District of northeast Tanzania, an area typifying the so-called 'affected drylands' of Africa. Three sets of land cover maps synchronized against long-term rainfall data (1960s, 1991 and 1999) were used to assess land degradation in the area. Utilizing these three sets of land cover maps as a basis for change detection, it is possible to distinguish areas that experienced changes in vegetation due to rainfall variability from those areas that were subject to changes consequent upon anthropological factors. All areas that displayed overall depletion of natural and semi-natural vegetation due to human factors were deemed to have undergone land degradation, whereas areas that experienced inter-annual land cover changes due to rainfall variability were classified as experiencing cover change due to ecosystem dynamics. This method provides a complete and appropriate assessment of land degradation in the study area and can be used to improve degradation assessment in other semiarid areas.

Establishing landuse/cover change patterns over the last two decades and associated factors for change in semi arid and sub humid zones of Tanzania

“…Similar cases were also reported by individuals who participated in FGDs in both zones. Kiunsi and Meadow [2] also observed a similar case when studying land management issues in Monduli, Tanzania.…”

“…Nzega is one of the six districts of Tabora region, which covers the area of 9226 km 2 , and lies between longitudes 36˚30' and 33˚30'E and latitudes 3˚45' and 5˚00'S. The District is characterized by unimodal type of rainfall, which falls between November and April.…”

“…Such resources have been dwindling in many places but in some places where sustainable management are in place and not transformed to other emerging new landuse (LU) both non wood and wood products play a significant role in terms of providing both products and other services [2,3]. A number of studies in the region have reported for example how different livelihood system interacted with natural resources in the past where natural resources were not under pressure and what is recently happening [4,5].…”

The State of Soil Degradation in Sub-Saharan Africa: Baselines, Trajectories, and Solutions

“…Using only one of these indicators would easily lead one to different conclusions regarding the extent of degradation. Between the 1991 and 1999, however, was the rapid increase (by almost 1700%) in the presence of gullies and bare land, (equivalent to 1400 ha per year across 400,000 ha [99]). …”

Multisensoral Topsoil Mapping in the Semiarid Lake Manyara Region, Northern Tanzania

“…This results in a sparsely-vegetated semiarid environment dominated by bushy grassland. The study area is also characterized by a variety of degradation processes due to long dry periods and short, but intensive rainfall events, as well as contributing anthropological factors, like overgrazing [46]. The lithology of the study area is very complex, because different lithological units interleave here.…”