Forest edge effects on moss growth are amplified by drought

Forest fragmentation increases the amount of edges in the landscape. Differences in wind, radiation and vegetation structure create edge-to-interior gradients in forest microclimate, and these gradients are likely to be more pronounced during droughts and heatwaves. Although the effects of climate extremes on edge influences have potentially strong and long-lasting impacts on forest understory biodiversity, they are not well understood and are not often considered in management and landscape planning.
Here we used a novel method of retrospectively quantifying growth to assess biologically relevant edge influences likely caused by microclimate using Hylocomium splendens, a moss with annual segments. We examined how spatio-temporal variation in drought across three years and 46 sites in central Sweden, affected the depth and magnitude of edge influences. We also investigated whether edge effects during drought are influenced by differences in forest structure.
Edge effects were almost twi..., The data is from 46 boreal forest edges in central Sweden. The datasets consist of measurements of yearly growth of the moss Hylocomium splendens along edge-to-interior transects, as well as data on site-level, including canopy cover, tree height and drought intensity.
Moss measurements: At each forest edge, we collected shoots of the moss H. splendens along edge-to-interior transects at the following distances: 0, 5, 10, 20, 30 and 50 m. We collected three moss samples (minimum 7 shoots) perpendicular to the transect at each distance. We measured yearly growth three years back in time (2016, 2017 and 2018, one segment per year) of 21 moss-shoots at each distance, resulting in a total of 17 293 measurements. A more extensive explanation of these measurements is found in the method section of the article.
Site-level data: Forest structural variables were measured at five locations in the forest interior. These five locations were approximately 10 m apart along a transect parallel to the..., R and Excel are required for the files.

森林破碎化会增加景观中的林缘（forest edge）总量。风速、辐射与植被结构的差异会形成森林微气候（microclimate）的林缘-林内梯度（edge-to-interior gradient），且这类梯度在干旱（drought）与热浪（heatwave）事件期间往往更为显著。尽管气候极端事件对林缘效应的影响，可能会对林下生物多样性（understory biodiversity）造成强烈且持久的冲击，但目前学界对其认知仍较为匮乏，且在森林经营与景观规划中也鲜有考量。

本研究采用一种回溯性量化生长量的创新方法，以具有年生长段的苔藓——美丽塔藓（Hylocomium splendens）为研究对象，评估由微气候驱动的、具有生物学意义的林缘效应。我们以瑞典中部46个样地（site）为研究对象，结合三年间的干旱时空变异特征，分析了林缘效应的作用深度与强度变化。此外，本研究还探讨了干旱期间的林缘效应是否会受森林结构差异的调控。

林缘效应强度近乎为……（原文此处截断）。本研究数据源自瑞典中部的46处北方针叶林林缘（boreal forest edge），数据集包含沿林缘-林内样带采集的美丽塔藓年生长量测量数据，以及样地尺度（site-level）的相关数据，具体包括冠层覆盖度、树高与干旱强度。

苔藓样本测量：在每个林缘样地中，我们沿林缘-林内样带，在距林缘0、5、10、20、30与50米的位置采集美丽塔藓的茎枝样本。在每个采样距离处，我们沿垂直于样带的方向采集3份苔藓样本（每份至少包含7根茎枝）。我们针对每个采样距离处的21根苔藓茎枝，回溯测量了其近三年（2016、2017与2018年，每年对应一个生长段）的年生长量，最终累计得到17293组测量数据。关于该测量方法的详细说明，可参见本文的方法学章节。

样地尺度数据：我们在林内的5个采样点测量了森林结构变量，这5个采样点沿平行于……的样带分布，间距约为10米。处理该数据集需用到R与Excel软件。