Details

Autor(en) / Beteiligte

• D'Onofrio, Donatella
• von Hardenberg, Jost
• Baudena, Mara

Titel

Not only trees: Grasses determine African tropical biome distributions via water limitation and fire

Ist Teil von

• Global ecology and biogeography, 2018-06, Vol.27 (5/6), p.714-725

Ort / Verlag

Oxford: John Wiley & Sons Ltd

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Aim: Although much tropical ecology generally focuses on trees, grasses are fundamental for characterizing the extensive tropical grassy biomes (TGBs) and, together with the tree functional types, for determining the contrasting functional patterns of TGBs and tropical forests (TFs). To study the factors that determine African biome distribution and the transitions between them, we performed the first continental analysis to include grass and tree functional types. Location: Sub-Saharan Africa. Time period: 2000–2010. Major taxa studied: Savanna and forest trees and C4 grasses. Methods: We combined remote-sensing data with a land cover map, using tree functional types to identify TGBs and TFs. We analysed the relationships of grass and tree cover with fire interval, rainfall annual average and seasonality. Results: In TGBs experiencing < 630 mm annual rainfall, grass growth was water limited. Grass cover and fire recurrence were strongly and directly related over the entire subcontinent. Some TGBs and TFs with annual rainfall > 1,200 mm had the same rainfall seasonality but displayed strongly different fire regimes. Main conclusions: Water limitation to grass growth was fundamental in the driest TGBs, acting alongside the well-known limitation to tree growth. Marked differences in fire regimes across all biomes indicated that fire was especially relevant for maintaining mesic and humid TGBs. At high rainfall, our results support the hypothesis of TGBs and TFs being alternative stable states maintained by a vegetation–fire feedback for similar climatic conditions.