Energetic increases lead to niche packing in deep-sea wood falls

Mechanisms leading to variation in diversity over energetic gradients continue to challenge ecologists. Changes in diversity may reflect the environmental capacity to support species’ coexistence through increased niche packing or niche space expansion. Current ecological theory predicts increases of energy may lead to both scenarios but not their relative strengths. We use experimental deep-sea, wood-fall communities, where energy supply can be controlled, to test for the importance of niche expansion and packing in functional space over an energetic gradient. Invertebrate communities were identified and counted from 16 Acacia sp. logs ranging in size from 0.6 to 20.6 kg in mass (corresponding to energy availability) deployed at 3203 m in the Pacific Ocean for 5 years. We use four fundamental energetic species-level functional traits--food source, trophic category, motility, and tiering--to characterize species niches. Increases in energy on wood falls lead to increases of species ri...驱动能量梯度下多样性变化的机制，始终是生态学家面临的棘手研究难题。多样性的变化可反映环境通过增强生态位打包（niche packing）或拓展生态位空间（niche space expansion）来维持物种共存的能力。当前生态学理论预测，能量供给提升可触发上述两种情景，但无法预测二者的相对优势。本研究利用能量供给可人为调控的实验性深海木材沉降群落（wood-fall community），探究能量梯度下生态位扩张与打包在功能空间（functional space）中的重要性。研究人员对太平洋3203米水深处投放5年的16根金合欢属（Acacia sp.）原木（质量范围0.6~20.6 kg，对应能量可获得性）中的无脊椎动物群落进行了物种鉴定与计数。本研究选取4个核心的物种级能量相关功能性状——食物来源、营养类群、运动能力与分层模式——来表征物种种位。木材沉降生境的能量提升会带来物种……