Data from: Arboreal ant abundance tracks primary productivity in an Amazonian whitewater river system

Little is known about consumer productivity in the tropics despite the key feedbacks that animals impose on primary productivity. In the Amazon basin, seasonally flooded and unflooded forests exist side by side, and ants (Formicidae) dominate animal biomass. Although flooding has a direct, negative effect on soil-dwelling ants, it is less clear whether flooding has indirect effects on arboreal ants via associated changes in tree communities. To test whether seasonal inundation by whitewater affects arboreal ants, we investigated ant communities in adjacent flooded and unflooded forests along a major whitewater river in central-western Amazonia. Whitewater-flooded forest exhibits higher primary productivity than unflooded forest. We thus hypothesized that forest type would affect the productivity and the foraging traits of arboreal ants, and that these changes would be mediated by increases in plant-derived food for ants in flooded forest. We compared ant and plant communities between flooded and unflooded forest transects along the Juruá River in Amazonas, Brazil. We collected, identified, and counted terrestrial and arboreal ants, and we measured ant traits with putative relationships to foraging strategy. We also identified plant stems to characterize the abundance of ant food rewards. Flooding negatively affected the diversity and abundance of terrestrial ants but did not change the diversity of arboreal ants. Arboreal ants were more abundant and exhibited higher biomass in flooded forest than in unflooded forest. Arboreal ant traits also suggested that ants may rely more heavily on plant-derived food in flooded forest than in unflooded forest. These differences were associated with a higher abundance of plant stems predicted to contain ant food rewards in flooded forest than in unflooded forest. Our results indicate that the productivity of arboreal ants is affected by that of the underlying forest. Such effects may be mediated by the predominantly herbivorous foraging strategy of canopy ants, which would link ant populations closely to primary production and stoichiometry. Given ants' important functional roles, these differences in ant productivity between forest types may have consequences for other arthropods and feedbacks to plants throughout the Amazon basin.

尽管动物会对初级生产力（primary productivity）产生关键的反馈调控作用，但学界对热带地区消费者的生产力水平仍缺乏充分认知。在亚马逊流域，季节性水淹林与非水淹林比邻共存，蚁科（Formicidae）昆虫在动物生物量中占据主导地位。虽然水淹对土壤栖居蚂蚁（soil-dwelling ants）存在直接负面影响，但水淹是否会通过树木群落的相关变化对树栖蚂蚁（arboreal ants）产生间接影响，目前仍不明确。为检验白水季节性淹没是否会影响树栖蚂蚁，我们针对亚马逊中西部一条大型白水河沿岸相邻的水淹林与非水淹林展开了蚂蚁群落调查。白水水淹林的初级生产力高于非水淹林，据此我们提出假说：林分类型会影响树栖蚂蚁的生产力与觅食性状，且这类变化会通过水淹林内蚂蚁可获取的植物源性食物增加来介导。我们在巴西亚马逊州的茹鲁阿河沿岸，对比了水淹与非水淹林样带内的蚂蚁与植物群落。我们采集、鉴定并统计了陆生蚂蚁与树栖蚂蚁，并测定了与觅食策略存在潜在关联的蚂蚁功能性状。同时，我们通过鉴定植物茎秆特征，量化了蚂蚁可获取食物奖励的植物丰度。研究发现，水淹对陆生蚂蚁的多样性与丰度存在负面影响，但未改变树栖蚂蚁的多样性。水淹林内的树栖蚂蚁丰度与生物量均高于非水淹林。树栖蚂蚁的功能性状同样显示，相较于非水淹林，水淹林内的蚂蚁可能更依赖植物源性食物。这类差异与水淹林内被预测可提供蚂蚁食物奖励的植物茎秆丰度更高有关。我们的研究结果表明，树栖蚂蚁的生产力受其所在林分的生产力影响。这类效应可能通过树冠蚂蚁以植食性为主的觅食策略介导，该策略可将蚂蚁种群与初级生产及化学计量学（stoichiometry）紧密关联起来。鉴于蚂蚁发挥着重要的生态功能，不同林分类型间的蚂蚁生产力差异，可能会对其他节肢动物产生影响，并对整个亚马逊流域的植物产生反馈效应。