The eco-evolutionary history of Madagascar presents unique challenges to tropical forest restoration

High biodiversity and endemism combined with persistently high
deforestation rates mark Madagascar as one of the hottest of biodiversity
hotspots. Contemporary rising interest in large-scale reforestation, both
globally and throughout Madagascar itself, presents a promising impetus
for forest restoration and biodiversity conservation across the island.
However, Madagascar may face unique restoration challenges due to its
equally unique eco-evolutionary trajectory, which must be understood to
enable successful ecological restoration. We conducted a systematic review
of potential barriers to restoration for terrestrial forest biomes
(rainforests, dry forests, subhumid highland forests) in Madagascar. Our
results indicate that aboveground biomass recovery of Malagasy forests
appears slower than other tropical forests. We suggest four key
synergistic factors that inhibit restoration in Madagascar: (a) Lack of
resilience to shifting nutrient and fire regimes arising from widespread
high-intensity shifting cultivation; (b) Predominance of nutrient-poor,
highly weathered ferralitic soils; (c) Vulnerability of regenerating
native trees to competition with invasive species due to their
evolutionary isolation; and (d) Low seed dispersal into regenerating
forests due to the unique dependence of Malagasy trees on dispersal by
forest-dependent endangered or extinct primates. However, we note that
rigorous experimental study of regenerating forests in Madagascar is
currently lacking. There is great opportunity and need for such research
to disentangle drivers and interactions inhibiting forest restoration.
These studies would enable reforestation practitioners to effectively
capitalize on current global momentum to implement the large-scale
restoration necessary for the conservation of Madagascar's numerous
endemic species.

马达加斯加兼具极高的生物多样性与特有性，同时森林砍伐率长期居高不下，是全球最受关注的生物多样性热点地区之一。当前，全球范围内与马达加斯加国内对大规模造林的关注度均持续攀升，为全岛森林恢复与生物多样性保护提供了极具潜力的发展契机。然而，马达加斯加因其独特的生态-进化历程，可能面临别具一格的恢复挑战，唯有充分理解这一历程，方能实现成功的生态恢复。本研究针对马达加斯加陆地森林生物群系（热带雨林、干旱林、亚湿润高地林）的恢复潜在障碍开展了系统性综述。研究结果显示，马达加斯加森林的地上生物量恢复速度似乎慢于其他热带森林。本研究提出了制约马达加斯加森林恢复的四大协同作用因子：（a）广泛实施的高强度刀耕火种导致其养分循环与火况发生改变，生态系统难以恢复韧性；（b）区域内大面积分布养分贫瘠、高度风化的砖红壤性土（ferralitic soils）；（c）本土树木因进化孤立性，其更新幼苗极易受到入侵物种的竞争压制；（d）马达加斯加本土树木独特地依赖以森林为栖息地的濒危或已灭绝灵长类进行种子传播，导致更新森林的种子补给量严重不足。但需指出，当前针对马达加斯加更新森林的严谨实验研究仍较为匮乏。开展此类研究以厘清制约森林恢复的驱动因子与交互作用，兼具重要意义与广阔前景。此类研究将助力造林从业者充分利用当前的全球热潮，落地大规模森林恢复行动，以切实保护马达加斯加众多特有物种。