The alien flora of Sudan and South Sudan: taxonomic and biogeographical composition

Ali Omer,Petr Pyšek,Haytham H Gibreel,Maha Kordofani,Mark Van Kleunen

doi:10.1007/s10530-021-02495-7

Abstract

Studies on plant invasions depend on local and regional checklists of the alien flora. However, global overview studies have shown that some regions, including many African countries, remain understudied in this regard. To contribute to filling this gap, here we present the first checklist of alien plants of Sudan and South Sudan (the Sudans). We analysed the taxonomic and geographical composition of the species on this list. Our result show that of the 113 alien species in Sudans (99 in Sudan and 59 in South Sudan), 92 (81.4%) are naturalized and 21 (18.6%) are just casual aliens. The number of naturalized species represent 2.2% of the total flora of the Sudans (4096). The alien species belong to 44 families and 85 genera, and many of them are native to Southern America and Northern America (85.8%). Annual and perennial herbs are the prevailing life forms in the alien flora of the Sudans (68.1%), and, among the casual species, perennial herbs are underrepresented whereas woody tree species are over-represented. Alien plants of the Sudans are mostly used for medicinal and environmental purposes globally. The naturalized plants predominantly occur in man-made disturbed habitats, such as agricultural and ruderal habitats. This first overview of the alien flora of the Sudans should stimulate further research and recording of the alien flora to better understand the drivers and consequences of alien plants in the Sudans.

Highlights

The introduction and subsequent establishment of alien plant species outside their native ranges is among the main drivers of ecosystem and biodiversity changes globally (Pysek et al 2020, 2012; Vilaand Hulme 2017)
To contribute to filling this knowledge gap, we present the first inventory of the alien flora of Sudan and South Sudan
We aimed to (i) identify the stage that alien plant species reached in the invasion process, using the definitions proposed by Richardson et al (2000), (ii) analyse taxonomic, geographical and ecological patterns in the alien flora, and (iii) analyse whether the casual and naturalized alien species differ in their species characteristics in the Sudans

Summary

Introduction

The introduction and subsequent establishment of alien plant species outside their native ranges is among the main drivers of ecosystem and biodiversity changes globally (Pysek et al 2020, 2012; Vilaand Hulme 2017). There are more than 13,000 alien plant species that have managed to establish wild populations (i.e. have become naturalized, Blackburn et al 2011; Richardson et al 2000) outside their native ranges (van Kleunen et al 2015). The numbers are still increasing (Seebens et al 2017), and this trend is predicted to continue (Seebens et al 2021) This alarming situation has stimulated studies that focus on drivers and consequences, i.e. impacts, of plant invasions. Such studies heavily rely on investigations of local, regional and global alien floras (Ansong et al 2019; Baard and Kraaij 2014; Inderjit et al 2018; Khuroo et al 2012; Lambdon et al 2008; van Kleunen et al 2015). It is vital to make regional checklists of alien floras that are as comprehensive and accurate as possible (Pysek et al 2017a)

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Conclusion