Long-term change in the forest-grassland mosaic of Central Highlands, Madagascar, and its conservation implications

Authors:
Andriantsilavo Razafimanantsoa

Publication Date:
2019

Abstract/Summary:
Ecosystem degradation has been reported worldwide but particularly in the tropics where it was accentuated by deforestation. For Madagascar, the Central Highlands, thought to have been covered by forest, are currently dominated by grassland. As a result, restoration projects were conducted in these areas, but so far, very few results have been recorded. However, the success of such an approach can only be guaranteed with full understanding of ecological processes which occur on a scale of centuries to millennia. This research aims to reconstruct the vegetation and fire history of two sites in the region during the Holocene using fossil pollen, carbon isotopes, and microscopic charcoal in sediment samples. Results show that the first site, Ambohitantely, was dominated by C3 plants before 1300 yr BP, confirmed by the abundance of Podocarpus (Podocarpaceae), Syzygium (Myrtaceae), Proteaceae, and Ericaceae pollen, but shifted to C4 plants (Poaceae dominated) from 1300 yr BP to the present period. Current abundance of grassland in the area correlated positively with increased fire events as identified through charcoals. However, Dangolahy, the second site, displayed an abundance of C3 plants over time from the late Holocene even with the slight increase in grass at the near present period, which coincides with increase of charcoals. These results indicate that within the Central Highlands, there were internal differences in vegetation histories which suggest different management strategies. If Ambohitantely would benefit from restoration projects by reintroducing its tree component, Dangolahy would require monitoring of fire frequency to maintain its local biodiversity.

Resource Type:
Audio/Video, Conference Presentation, SER2019

Pre-approved for CECs under SER's CERP program

Source:
Society for Ecological Restoration