Impacts of woody invasive alien plant species on rural livelihood: Generalized propensity score evidence from Prosopis spp. invasion in Afar Region in Ethiopia

Abstract

This study applied a generalized propensity score method to evaluate the impact of Prosopis invasion on Afar pastoralist and agro-pastoralist households' annual per capita consumption expenditure, as a proxy of rural livelihoods. The analysis was based on cross-sectional survey data collected in mid-2016 from 250 households in the Afar National Regional State in Ethiopia. The method was applied to match households with similar covariates with different Prosopis invasion levels. The method was effective in teasing out non-linear causal relationships between Prosopis invasion dose and household per capita consumption expenditure. Average dose-response or impact function was obtained by estimating average annual household per capita consumption expenditure at different levels of Prosopis invasion. Initially, the plants' impact was positive, but turned negative after an optimum invasion dose. The optimal invasion dose of Prosopis was found to be 22.23%. The corresponding optimum level of annual household per capita consumption expenditure was found to be 4,500.50 Ethiopian Birr (USD 198). The results suggest that to maximize the benefits of Prosopis and minimize its adverse effects on the livelihoods of the pastoral and agro-pastoral communities, diverse management strategies that take into account not only the intensity of invasion, but also patterns of dryland economy should be implemented.

Impacts of climate change on current and future invasion of Prosopis juliflora in Ethiopia: environmental and socio-economic implications

“…According to the perception of many pastoralists, livestock are everything for them (sources of food, income, security, social status, cultural value, insurance, etc.) and therefore, there are willing to pay any sacrifices to get forage and water for these animals ( Bekele et al., 2018 ). This issue goes beyond biodiversity and economic reasons and has peace and security elements calling for integrated and coordinated actions at Federal and Regional levels to eradicating or minimizing the negative impacts of P. juliflora on pastoral production system ( Rogers et al., 2017 ).…”

“…Now, the species is listed among the world's ten worst invasive weeds ( Shrestha et al., 2018 ) and emerged as a significant threat to Africa's ecological landscapes ( Wakie et al., 2014 ). Nationally, the species is one of the worst invasive species, threatening the environment in arid and semi-arid ecosystem of Africa, and affect the livelihood of pastoral and agro-pastoral society ( Bekele et al., 2018 ; Mbaabu et al., 2019 ; Shackleton et al., 2015 ; Zeray et al., 2017 ). Recent studies showed that rate of P. juliflora invasion is increasing significantly, suppressing native plant species ( Ayanu et al., 2014 ; Haregeweyn et al., 2013 ; Shiferaw et al., 2019c , Shiferaw et al., 2019d ).…”

“…Ecological niche modeling (ENM) of species distribution model is now widely used to computerize algorithms to predict the distributions of a species across a geographical space and time, based on observed distributions of a species as a function of environmental conditions ( Araújo and New, 2007 ). Several studies in Ethiopia have focused on its impacts on land use, land cover and livelihoods ( Bekele et al., 2018 ; Shiferaw et al., 2019a ; Zeray et al., 2017 ), spatial coverage in small geographical area in particular in Afar Regional State ( Shiferaw et al., 2019c , Shiferaw et al., 2019d ; Wakie et al., 2014 ), and biodiversity loss ( Mehari, 2015 ; Shiferaw et al., 2019c , Shiferaw et al., 2019d ; Zeray et al., 2017 ) in small geographical area in particular in Afar Regional State. However, a dearth of information on spatial distribution at national scale in Ethiopia and the relations between P. juliflora expansion and climate change dynamics as projected have been explored at a national level, in spite of the fact that this invasive plant species is rapidly expanding at the rate of 31,127 ha annually in Afar Regional State ( Shiferaw et al., 2019a ) and causing biodiversity loss ( Shiferaw et al., 2019c , Shiferaw et al., 2019d ; Wakie et al., 2014 ; Witt et al., 2018 ).…”

The Impact of Invasive Alien Plants on Rangelands in South Africa

“…Physical damage to livestock by well-armed alien plants has been recorded in East Africa for Opuntia stricta (Australian Pest Pear) (Shackleton et al 2017) and Prosopis spp. (Bekele et al 2018), most commonly by thorns damaging hooves.…”

“…Prosopis is one of the few invasive alien taxa whose ecological and economic impacts have been reasonably well studied in South Africa (van den Berg 2010; Milton and Dean 2010;Ndhlovu et al 2011Ndhlovu et al , 2016Shackleton et al 2015;Zimmermann and Pasiecznik 2005;Dzikiti et al 2018; see also Bekele et al (2018) for information from Ethiopia). The genus Prosopis includes several tree species and their hybrids that have successfully invaded the Nama-Karoo, Succulent Karoo, and semi-arid Savanna Biomes.…”