Mimosa diplotricha

Witt, Arne, Chimphepo, Lilian, Beale, Tim & Nunda, Winnie, 2020, Distribution of Mimosa diplotricha in eastern and southern Africa and its socio- ecological impacts in northern Malawi, Bothalia (a 9) 50 (1), pp. 1-13 : 7

Mimosa diplotricha occurrence

The field surveys, literature reviews and questionnaires indicate that M. diplotricha is relatively widespread with localised invasions in a number of countries in eastern Africa but less so in southern Africa, with significant invasions only in the north and southeast of Malawi with some records from Mozambique, although the latter was never surveyed during this study, so its current status there is unknown. In Ethiopia, the plant is abundant along roadsides from Wolisso to Jimma in the southwest. In many areas the plant is scrambling over the edge of the road, blocking footpaths and waterways (Wakjira 2011). According to community members in Merewa Kebele in Kersa Woreda, Ethiopia, the plant has been invading roadsides for the past three to five years with road construction contributing to its spread (Wakjira 2011). In our study only eight per cent of respondents said that road construction contributed to the spread of mimosa with 41% saying that it was spreading naturally and with 31% being unsure.

Respondents to the questionnaire indicated that it is still spreading in Malawi, an indication that it has the potential to spread even further in the region as a whole, especially into tropical and sub-tropical regions within eastern and southern Africa. A CLIMEX ecoclimatic model developed by T. Beale (unpublished) indicates that most of Uganda, Rwanda and Burundi have climates suitable for mimosa invasions while northern Tanzania and its coastline, extending across much of the interior towards Malawi, also appear to be a good climatic match. Our surveys further support the model by indicating that the southwest of Ethiopia and northern and southeastern Malawi are climatically suitable. Areas in which no mimosa was seen during surveys, such as the southwest of Kenya and its coastline are also a climatic match and as such likely to be invad- ed should mimosa be introduced and establish there. Much of the coastline of Mozambique, extending inland to southern Malawi, and the northeastern coast of South Africa also appear to be climatically suitable, together with the whole of the eastern Madagascan seaboard (T. Beale unpublished). It is unlikely to establish and proliferate in Zimbabwe, Botswana, Namibia and Zambia, but much of northern Angola appears to be a good climatic match. Low temperatures are also likely to limit the species, which means that high-lying areas/regions are unlikely to be invaded although it has been found at 1500–2000 m above sea level ( Henty & Pritchard 1973; Kostermans et al. 1987).