Abstract Detail

Biogeography

Mairal, Mario [1], Namaganda, Mary [2], Gizaw, Abel [3], Chala, Desaleng [3], Brochmann, Christian [4], Catalan, Pilar [5].

Multiple mountain-hopping colonization of sky-islands on the two sides of Tropical Africa during the Pleistocene: the afroalpine Festuca grasses.

The afroalpine sky-islands present one of the most interesting models to study discrete biogeographic patterns in a terrestrial island system. Here, we performed range-wide sampling of the afroalpine clade of fine-leaved Festuca grasses. We focus on the widespread species F. abyssinica and explore the role of the eastern and western African sky-islands in the evolution of biodiversity and its dispersal patterns. We combine data from field surveys, phylogeography, environmental niche and dispersal costs analyses to infer patterns of genetic diversity, genealogical relationships, colonization routes, and range shifts associated with recent climate changes. The westernmost populations in East Africa show higher genetic diversity and higher similarities with the Ethiopian Simen Mountains and the West African populations than with the more closely situated East African populations. Dispersal models and ecological niche predictions of F. abyssinica supported multiple long-distance dispersals among the eastern African sky-islands, and at least two dispersal events between the two sides of Africa (0.86 Ma, 0.52 Ma), probably facilitated by bridging suitable habitats during the coldest periods of the Pleistocene. We hypothesize an afroalpine mountain-hopping dispersal model, with migrations occurring between adjacent sky-islands in eastern Africa, and through a Central Africa - Sudan pathway connecting afroalpine patches on the two sides of the continent.

1 - Stellenbosch University, Cape Town, WC, 7600, South Africa
2 - Makerere University, Botany, Kampala, Uganda
3 - Natural History Museum, Plant Evolution, Oslo, NO-0318, Norway
4 - University Of Oslo, Natural History Museum, National Centre For Biosystematics, Oslo, 03, NO-0318, Norway
5 - Escuela Politecnica Ctra. Cuarte Km 1, Huesca, HU, 22071, Spain

Keywords:
Afroalpine Festuca
dispersal cost analysis
eastern and western Tropical Africa
ecological niche modelling
long distance dispersal
phylogeography.

Presentation Type: Poster
Session: P, Biogeography Posters
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 5:00 PM Time and date to be determined
Number: PBG008
Abstract ID:626
Candidate for Awards:None