Why are woody plants fleshy-fruited at low elevations? Evidence from a high-elevation oceanic island
Albert S., Flores O., Rouget M., Wilding N., Strasberg D.. 2018. Journal of Vegetation Science, 29 (5) : p. 847-858.
DOI: 10.1111/jvs.12676
Question: The composition of fruit types, fleshy vs dry fruits, greatly influences the functioning of plant communities. Literature documenting spatial patterns of fruit types at fine scale is abundant. However, studies at larger geographical scale remain scarce, especially on high-elevation oceanic islands that provide a great environmental heterogeneity. Here, we investigated how abiotic factors explained the proportion of fleshy-fruited species (pFF) on Réunion. We asked (a) which abiotic factors were most related to pFF, (b) if fleshy-fruited canopy species were more sensitive than fleshy-fruited shrubs to harsh climatic conditions and (c) what are the relationships between pFF, endemism and phylogenetic relatedness. Location: Réunion (3,070 m a.s.l), Mascarene archipelago, South-West Indian Ocean. Methods : We used a dataset of 429 vegetation plots and assigned fruit types, growth forms and geographical distribution to 213 native woody species. Phylogenetic trees were constructed for each plot. We used GLMs to measure the relationship between pFF and abiotic factors, controlling for spatial autocorrelation. We then assessed the relationship between pFF, the standardized net relatedness index and the proportion of endemic species. Results: The top model explained 78% of the variation in pFF. Elevation was by far the best predictor, with pFF decreasing from 81% at 50 m a.s.l to 0% at 3,000 m a.s.l. At low elevations, pFF was higher on the wet windward (81%) than on the leeward (70%) where phylogenetic clustering was evident. Almost half (48%) of woody plants was fleshy-fruited trees at low elevations. The proportion of fleshy-fruited trees declined sharply with elevation and was significantly related to precipitation of the driest month contrary to the proportion of fleshy-fruited shrubs that showed a hump shaped pattern along elevational gradient and no correlation with precipitation of the driest month. At high elevations, most plant assemblages were phylogenet
Mots-clés : communauté végétale; phylogénie; altitude; facteur climatique; île; biogéographie; fruits tropicaux; arbuste; endémisme; la réunion; france
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Agents Cirad, auteurs de cette publication :
- Flores Olivier — Bios / UMR PVBMT
- Rouget Mathieu — Bios / UMR PVBMT
- Wilding Nicholas — Bios / UMR PVBMT