Data from: Resource use and food preferences in understorey ant communities along a complete elevational gradient in Papua New Guinea

Elevational gradients provide an interesting opportunity for studying the effect of climatic drivers over short distances on the various facets of biodiversity. It is globally assumed that the decrease in species richness with increasing elevation follows mainly the decrease in ecosystem productivity, but studies on functional diversity still remain limited. Here, we investigated how resource use and food preferences by both individual ant species and communities foraging in the understorey vary with elevation along a complete elevational gradient (200 to 3200 m a.s.l.). Five bait types reflecting some of the main ecosystem processes in which ants are involved were tested: mutualism (sucrose and melezitose), predation (live termites) and detritivory (crushed insects and chicken faeces). The observed monotonic decrease in both species richness and occurrences with elevation increase was accompanied by changes in some of the tested ecosystem processes. Such variations can be explained by resource availability and/or resource limitation: predation and bird faeces removal decreased with increasing elevation possibly reflecting a decline in species able to use these resources, while insect detritivory and nectarivory were most probably driven by resource limitation (or absence of limitation), as their relative use did not change along the gradient. As a consequence, resource attractiveness (i.e., food preferences at the species level) appears as an important factor in driving community structuring in ants together with the abiotic environmental conditions.海拔梯度为探究短距离内气候驱动因子对生物多样性多维度特征的影响提供了绝佳研究契机。全球学界普遍认为，物种丰富度随海拔升高而降低的现象主要源于生态系统生产力的下降，但针对功能多样性（functional diversity）的相关研究仍较为匮乏。本研究依托一条完整的海拔梯度（200至3200米），探究了林下觅食的蚂蚁物种个体及群落的资源利用策略与食物偏好如何随海拔变化。本实验设置了五类诱饵，用以反映蚂蚁参与的核心生态系统过程：包括代表互利共生过程的蔗糖（sucrose）与松三糖（melezitose）、代表捕食过程的活白蚁，以及代表腐食过程的碾碎昆虫与鸡粪。研究观测到，物种丰富度与物种发生频次均随海拔升高呈现单调递减趋势，同时部分待测生态系统过程也发生了显著改变。上述变化可通过资源可获得性与/或资源限制效应加以解释：捕食行为与鸟粪清除率随海拔升高而下降，这可能反映了能够利用这类资源的蚂蚁物种数量减少；而昆虫腐食与食蜜（nectarivory）行为的相对占比未随海拔梯度发生变化，其驱动因素大概率为资源限制（或无资源限制）。综上，资源吸引力（即物种层面的食物偏好）与非生物环境条件共同构成了调控蚂蚁群落结构的关键因素。