Data from: Landscape context explains changes in the functional diversity of regenerating forests better than climate or species richness

Aim
A rich literature on forest succession provides general expectations for the steps forests go through while reassembling after disturbance, yet we still have a surprisingly poor understanding of why the outcomes of forest recovery after logging (or other disturbances) vary so extensively. In this paper, we test the hypothesis that regional species pool, system productivity, climate and landscape structure are important drivers of forest reassembly outcomes.
Location
Transect 1,500 km in length along the east coast of Australia.
Time period
Survey of 50- to 60-year-old rain forest regrowth and primary forest conducted in 2012 and 2013.
Major taxa studied
Rain forest plants.
Methods
In this study, we compare species and functional diversity patterns in pairs of remnant and regrowth (‘secondary’) rain forests spread across a 1,500 km climate and productivity gradient along the east coast of Australia. Our controlled natural experiment was designed to test the importance of regional species pool, system productivity, climate and landscape structure as drivers of species and functional diversity in regenerating forests. Notably, our study design allowed us to hold soil type, general forest type and disturbance history relatively constant in order to test our hypotheses effectively.
Results
Counter to expectations, few tested factors were strongly related to the recovery of species or functional diversity in regenerating Australian rain forests. The extent of local forest fragmentation was the only factor strongly related to differences between regrowth forests and primary forest remnants, and then only for functional diversity. We found no evidence that species diversity is a reasonable proxy for, or potential driver of, functional diversity patterns.
Main conclusions
Our findings suggest that forest functional recovery over decades is influenced more by regional landscape context than distinct assembly processes operating across climate and productivity gradients.

研究目的
大量关于森林演替（forest succession）的文献为森林受干扰后重建的步骤提供了一般性预期，但我们对采伐（或其他干扰）后森林恢复的结果为何存在如此广泛差异的理解仍惊人地匮乏。本文旨在检验以下假说：区域物种库（regional species pool）、系统生产力（system productivity）、气候与景观结构（landscape structure）是森林重建结果的重要驱动因子。

研究区域
沿澳大利亚东海岸延伸的1500公里样带。

研究时段
2012年与2013年对50至60年生雨林恢复林（rain forest regrowth）与原始林（primary forest）开展的调查。

研究类群
雨林植物。

研究方法
本研究对分布于澳大利亚东海岸1500公里气候与生产力梯度上的残留林与恢复林（即"次生"雨林（secondary rain forest））配对样地的物种多样性（species diversity）与功能多样性（functional diversity）格局进行比较。本对照性自然实验旨在检验区域物种库、系统生产力、气候与景观结构作为恢复森林中物种与功能多样性驱动因子的重要性。值得注意的是，本研究设计通过控制土壤类型（soil type）、森林总体类型与干扰历史相对一致，以有效检验所提出的假说。

研究结果
与预期相反，极少有测试因子与澳大利亚恢复雨林的物种或功能多样性恢复显著相关。局部森林破碎化（forest fragmentation）程度是唯一与恢复林与原始残留林之间差异显著相关的因子，且仅对功能多样性存在显著影响。本研究未发现证据表明物种多样性可作为功能多样性格局的合理替代指标（proxy）或潜在驱动因子。

主要结论
本研究结果表明，数十年尺度上的森林功能恢复受区域景观背景的影响远大于沿气候与生产力梯度运行的独特森林组装过程（assembly processes）。