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Pattern of crop raiding by wild large mammals and the resultant impacts vary with distances from forests in southwest Ethiopia

Citation

Lemessa, Debissa (2021), Pattern of crop raiding by wild large mammals and the resultant impacts vary with distances from forests in southwest Ethiopia, Dryad, Dataset, https://doi.org/10.5061/dryad.tht76hdz3

Abstract

Crop raiding is a major form of human-wildlife interaction mainly in the ecotone areas of human-modified-natural landscapes. The aim of this study was to examine the spatial pattern of crop raiding and the resultant impacts on how farmers perceive forests at different distances from Yayu Coffee Forest Biosphere Reserve which is located in southwest Ethiopia. For this, thirty transects (each 1km long) were laid out at 200m interval parallel to forest edges: ten transects close to forest (<0.5km), ten at intermediate (0.5-1km) and ten transects were taken far from forest (>1km). Along each transect 2-6 households were randomly selected and interviewed using semi-structured questionnaire. The perception of the respondents on forests at different distances from forest edges was analyzed using Pearson’s Chi-square test. The variation in the amount of damage among these three locations was tested using one-way ANOVA. Four wild large mammals including; olive baboon, vervet monkey, bush pigs and crested porcupine were identified as top crop raiders in the area. The frequencies of occurrence of crop raiders decreased with increasing distance from forest edges. Similarly, the amount of damage in maize fields was higher close to forests when compared with that of either at intermediate or far from forest edges (P<0.001). Eighty one percent of the households living close to the forests perceive that forest is a threat to their survival. Overall, our results imply that strategies need to be sought in order to minimize the socio-ecological impacts of crop raiders mainly in locations close to forest edges.

Methods

The first 1km long transect was laid out along the edges of Yayu Coffee Forest. In the next, 29 transects (each 1km long) were arranged with 200m interval in parallel to the first transect and to each other in the agricultural landscape. These transects were categorized into three locations: ten transects close to forest (<0.5km), ten intermediate (0.5-1km) and ten transects far from forest (>1km) in similar method used by Lemessa et al. (2013). By walking along each transect in zigzag way turning right and left, the households were randomly selected for questionnaire survey. Accordingly, from each three locations from forest edges (i.e., 48 households close to, 38 intermediate and 38 far away from forest households) or 2-6 households from each thirty transects and in total 124 households were interviewed using semi-structured questionnaire. This household level interview was executed during the crop growing and maturity seasons from February 1st to 30 July 2019.

The major data collected were the type of crop raiders and the frequency of occurrences per year, crop species liable to be raided, extent of crop damage and how the households perceive the about the Yayu Coffee Forest. The scientific names of the large mammals were identified using field guide of large mammals of Africa after their local or common names in Afaan Oromo were collected during the questioner survey ((Stuart, 2006). Moreover, after the maize crop was identified as the most liable to crop raiding, one maize field of each of 22, 21 and 21 households used for questionnaire survey were respectively selected from the three locations close to forest, intermediate and far away from forest edge at random to estimate the extent of crop raiding. Correspondingly, four permanent plots (size: 4´4m each) were randomly established in each of the 64 maize sown fields of the households (0.5ha each on average) in March 2019 and at the maturity stage the number of damaged stems due to crop raiding were recorded in July, 2019. Moreover, the amount of annual yield loss estimated by respondents was compared with the yield loss we computed based on the secondary data of the average annual yield of maize from Yayu District Agricultural Development Office of the study area (YDADO, 2019). Here, the percent of annual yield loss due to crop raiding was calculated in percent from the difference between the amount of annual maize yield from the field survey (actual yield of maize) and average annual yield of maize obtained from YDADO.