Non-random latitudinal gradients in range size and niche breadth predicted by spatial patterns of climate

Aim. Tropical species are thought to experience and be adapted to narrow ranges of abiotic conditions. This idea has been invoked to explain a broad array of biological phenomena, including the latitudinal diversity gradient and differential rates of speciation and extinction. However, debate continues regarding the broad-scale applicability of this pattern and potential processes responsible. Here, we use a simulation approach to test two propositions: (1) strong geographic patterns of variation in realized niche breadth can arise in the absence of variance in the size of fundamental niches, and (2) realized niche breadths can show latitudinal patterns as a consequence of spatio-temporal climate change, even when fundamental niche breadths are unrelated to latitude, and dispersal abilities are held constant.

Location. Global.

Time period. Simulations were conducted using climate models from over the last 120 Ka, with trait dynamics captured at 95 Ka and present-day.
Major taxa...

研究目标：学界普遍认为热带物种仅能在较窄的非生物条件范围内生存并适应此类环境。这一观点已被用以阐释诸多生物学现象，包括纬度多样性梯度（latitudinal diversity gradient）以及物种形成与灭绝的差异速率。然而，学界对于该模式的大范围适用性及其背后的潜在驱动过程仍存在争议。本研究采用模拟方法检验两项命题：（1）即使基础生态位（fundamental niche）大小不存在差异，仍可出现实际生态位宽度（realized niche breadth）变化的显著地理格局；（2）即便基础生态位宽度与纬度无关且扩散能力（dispersal ability）恒定，时空气候变化仍可使实际生态位宽度呈现纬度格局。
研究区域：全球范围。
时间范围：本研究采用过去12万年来的气候模型开展模拟，分别在9.5万年前和现代记录性状动态。
主要类群……