Habitat preference and distribution patterns for Helichrysum species in Rwanda

Abstract

Rwanda as a country located in the East Africa has different areas which are the hotspot of endemic plants species including Helichrysum species. The mountainous forests of the country are most areas in which Helichrysum species are diverse and distributed. The habitats of Helichrysum in Rwanda are located in the protected areas and non-protected areas. The habitats of Helichrysum in the non-protected areas have been experiencing destruction and fragmentation of habitat, which has been identified as a serious danger to biodiversity. Nevertheless, earlier research on plant conservation in East Africa disregarded unprotected areas in favour of protected ones. Understanding the distribution patterns and preferred habitats of plants in Rwanda will be crucial for developing future conservation plans for small plant species like Helichrysum. The locations can exhibit distinct characteristics in terms of its climate and ecology. To obtain the information on the characteristics of areas and habitats occupied by Helichrysum species in Rwanda, we carried out a field study in three National Parks (Nyungwe National Park, Volcanoes National Park, and Gishwati-Mukura National Park). To obtain crucial information on the chorology, species richness and habitats of Helichrysum, we examined numerous specimens from Global Biological Information, National Herbarium of Rwanda, and different literature which facilitated the identification of Helichrysum species occurred in the four climatic zone (the Eastern zone, the Western and Northern Highland zone, the Central Plateau zone, and the Lake Kivu side zone) of Rwanda. The results of the study showed that Helichrysum species are distributed in all the climatic zones and in both protected and non-protected areas of the country with 31 species. The protected areas (Nyungwe National Park and Volcanoes National Park) characterized with high mountainous forests and wet climate, and ericaceous belt at the top, are the most dominated areas with more than 20 Helichrysum species by each. The Akagera National Park has a lowest number of Helichrysum species with one species. In this study, non-protected areas were considered by district as their administrative units. The high number of Helichrysum occurred in non-protected areas are located in Huye and Nyamagabe districts with 10 species each, followed by Nyamasheke district with 10 species. Huye district has a part in the Central Plateau climatic zone which were found to be the third climatic zone in rich of Helichrysum species with 9 species after the Western and Northern High Lands with 31 species and 15 species in the Lake Kivu side. Helichrysum forskhalii was found the most distributed species in all the parts of Rwanda, while Helichrysum newii was found to be dominant in the high mountain areas of the Volcanoes National Park. The areas of Rwanda have a diverse of ecosystems in which Helichrysum species can have suitable habitats. The results showed that the ecosystems including forests, shrub lands, marshlands, supraforestal ericoid belt and savannah are the preferable and suitable habitats for Helichrysum species. Forest lands had 28 species, shrub lands had 23 species, while the rocky slope areas had a lowest number of Helichrysum with 9 species. The conservation initiatives in the future should focus on the scattered forest lands which are not protected and the shrub lands around the roadsides where small plants like Helichrysum have more suitable and preferred habitats. The further researches should consider the determination of the phytochemical and biological activities of Helichrysum species in Rwanda. This study will be helpful in the planning of strategies toward the conservation of Helichrysum in Rwanda