Abstract Detail

Floristics & Taxonomy

Rakotomalala, Nantenaina Herizo [1], Andriamanohera, Mihaja Andotiana [2], Rabehevitra, David [2], Solofondranohatra, Lova Cédrique [3], Jeannoda, Vololoniaina Hary [3], Andriatsitohaina, Ranaivojaona [4], Ralimanana, Hélène [2], Vorontsova, Maria [5].

Grasses of the Isalo National Park, Madagascar – checklist, origins, and significance.

The Poaceae are one of the most species-rich plant families in Madagascar, abundant but comparatively poorly known. Even professional botanists often ignore this group not only because they may appear homogeneous and less attractive, but also due to their popular reputation as weeds, and the locally common assumption that grasslands are degraded wastelands. We challenge these misleading assumptions and encourage the study and appreciation of Madagascar’s grasses. In this talk, I will share the outcome of my MSc project on the grasses of the Isalo National Park, home to beautiful savanna grasslands in the southern part Madagascar’s central highlands. We compiled a list of all the grass species found within the park to understand the diversity and endemicity of grasses, using both existing herbarium specimens and new field inventories, to present an overview of the beautiful diversity which grass species hold within their tiny reproductive structures. Our dedicated species inventory has doubled the list of species known from Isalo within ten years, and we expect to find further diversity in the inaccessible northern parts of the park. This grass-dominated and seemingly xerophytic ecosystem is home to 112 species of grasses: only one of Madagascar’s seven Poaceae subfamilies is missing in Isalo. Most of the grass species of Isalo are native and C4. Almost 22% of the species are endemic to Madagascar, including three species and one variety known only from Isalo. Isalo’s grasses are distributed across diverse habitats, but the greatest number species was recorded from in the extensive grasslands, where two beautiful locally endemic species create unusual ground cover with their spiky leaf apices: Tristachya humbertii A.Camus and Tristachya (Isalus isalensis). The history of Isalo ecosystem management of by the cattle herding Bara people, as well as the endemism and the native origin of its grasses and other species are consistent with an ancient origin of Isalo’s ecosystems. We argue for the continuation of this research and for the conservation of Isalo’s grassy ecosystems, as well as that research and conservation of the plants and animals that inhabit them.

Related Links:
This is in editing in the Madagascar Conservation and Development Journal

1 - Kew Madagascar Conservation Centre, RBG Kew, Lot B40 Ter Andrefantsena, Sabotsy Namehana, Antananarivo, Antananarivo, 103, Madagascar
2 - Kew Madagascar Conservation Centre, RBG Kew, Antananarivo, Antananarivo, 101, Madagascar
3 - Biology and Ecology Department, University of Antananarivo, Faculty Sciences, Antananarivo, Antananarivo, 101, Madagascar
4 - Madagascar National Park Ranohira, Madagascar National Park , Ranohira, Ihosy, Ihorombe, Madagascar
5 - Royal Botanic Gardens Kew, Royal Botanic Gardens Kew, Surrrey, Richmond, London, United Kingdom, 103, Madagascar

Keywords:
Grasses
Madagascar
diversity
endemicity
Grasslands
conservation.

Presentation Type: Oral Paper
Session: FTII, Floristics & Taxonomy II
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 1:15 PM(EDT)
Number: FTII004
Abstract ID:724
Candidate for Awards:None