Water and fish select for fleshy fruits in tropical wetland forests

Adjacent floodplain and upland tropical forests experience the same temperature and precipitation regimes, but differ substantially in plant species composition and biotic interactions because of extensive flooding. We hypothesize that flooded forests filter fruiting traits linked to seed dispersal by water and fishes, such that selection by water and fish led to (1) trees that synchronize the timing of fruiting with annual floods, and (2) the evolution of fleshy tissues on fruits to improve buoyancy and increase fruit consumption rates by fish. To test this hypothesis, we compared plant communities in seasonally flooded forests and adjacent upland forest in terms of fruiting phenology, the frequency of trees bearing fleshy-fruit, and the role of fleshy tissues in buoyancy and seed viability. Beta-diversity in this system is high, with significant differences in species composition across habitats. As predicted, the production of ripe fleshy fruits was significantly greater in flooded t...毗邻的泛滥平原热带林与丘陵旱地热带林具有一致的温度与降水格局，但因长期浸水，二者在植物物种组成与生物互作方面存在显著差异。本研究提出假说：泛滥林会筛选出与水和鱼类介导的种子扩散相关的结实性状，即水与鱼类的选择压力将催生两类演化特征：其一，树木的结实时间与年度洪水周期同步；其二，果实演化出肉质组织以提升浮力，并提高鱼类取食果实的频次。为验证该假说，本研究从结实物候（fruiting phenology）、结肉质果树木的占比，以及肉质组织对浮力与种子活力的影响三个维度，比较了季节性泛滥林与毗邻丘陵旱地林的植物群落。该研究系统的β多样性（beta-diversity）较高，不同生境间的物种组成存在显著差异。正如预期，泛滥生境中成熟肉质果的产出量显著高于...