Foliar N content parallels increasing aridity in a Mediterranean-Saharan transition zone: Evidence from regional and global trends

Aim Warm deserts are characterized by water shortages and high-temperature extremes. A common adaptive strategy in such environments is the maximization of photosynthetic capacity, which allows plants to achieve positive carbon budgets by taking advantage of short periods of water availability and non-inhibitory temperatures. Assuming that photosynthetic capacity is approximated by leaf N concentration, we tested the hypothesis that environmental aridity is related to an elevated leaf nitrogen content.
Location 53 locations in the transitional zone spanning the Mediterranean and the Sahara Desert in Morocco. The mean maximal temperature (Tmax) within the area varied between 35.7 and 43.5 °C, and the mean annual precipitation (MAP) was between 12 and 246 mm.
Taxon 225 vascular species representative of local vegetation
Methods Leaf samples were collected along a regional aridity gradient and preserved in herbarium presses. The leaf mass per area (LMA) and N concentrations expressed on le..., Field sampling - Plant material was collected during two field trips conducted between 9 and 18 June 2011 and between 12 and 22 March 2012 at 53 sites located within the state limits of Morocco. Site selection was haphazard and was based on the presence of relatively undisturbed spontaneous vegetation. One to several species were sampled per site. Two aggregate samples consisting of several healthy, mature, well-illuminated leaves per species were collected, each from several separate individuals. The total number of taxa sampled (sometimes identified down to subspecific level but hereafter referred to as species) was 225; however, 22 species were sampled from two sites and one from three sites. The leaves were carefully placed between sheets of newsprint and blotting paper and pressed tightly in a herbarium press. The blotting paper was exchanged daily for several days until the material was dry.
Sample processing - Samples were transported to the laboratory, where areas of individual ..., , # Data from: Foliar N content parallels increasing aridity in a Mediterranean-Saharan transition zone: Evidence from regional and global trends

[https://doi.org/10.5061/dryad.qnk98sfqz](https://doi.org/10.5061/dryad.qnk98sfqz)

## Description of the data and file structure

This is the data used in the article 'Foliar N content parallels increasing aridity in a Mediterranean-Saharan transition zone: Evidence from regional and global trends' by Wyka et al. 

### Files and variables

#### File: README.md

**Description:** This file contains lists of variables for each of the three spreadsheets.

#### File: Wyka\_et\_al.\_Morocco Raw data.xlsx

**Description:** This data set consists of three spreadsheets entitled 'Morocco raw data', 'Morocco species means', and 'Press drying trial data'.

##### Variables:

1\) The sheet \"Morocco raw data\" contains location data, taxonomy, climate, and leaf trait measurements of individual leaf samples collected from 53 sites across Morocco. Column headi...

目标 暖荒漠的特征是水资源短缺和极端高温。此类环境中常见的适应策略是最大化光合能力（photosynthetic capacity），这使植物能够利用短暂的水分可利用期和非抑制性温度实现正碳平衡。假设光合能力可通过叶氮浓度（leaf N concentration）近似表征，我们验证了环境干旱度与叶氮含量升高相关的假设。

地点 摩洛哥境内横跨地中海与撒哈拉沙漠的过渡带中的53个地点。该区域内的平均最高温度（Tmax）介于35.7至43.5℃之间，年平均降水量（MAP）介于12至246毫米之间。

分类群 代表当地植被的225种维管植物（vascular species）。

方法 沿区域干旱梯度采集叶片样本，并保存在标本夹中。叶面积质量（LMA）和以叶...（原文此处截断）；野外采样——植物材料于2011年6月9日至18日及2012年3月12日至22日期间，在摩洛哥境内53个地点的两次野外考察中采集。地点选择为随机方式，基于存在相对未受干扰的自然植被。每个地点采集1至数种物种。每种物种采集两份混合样本，每份样本由来自若干独立个体的数片健康、成熟、光照良好的叶片组成。采样的分类群总数为225种（有时鉴定至亚种水平，但下文统称为物种）；然而，22种物种从两个地点采样，1种从三个地点采样。叶片被小心放置在新闻纸和吸水纸之间，并在标本夹中压紧。吸水纸连续数日每日更换，直至材料干燥。

数据来源：《地中海-撒哈拉过渡带中叶氮含量随干旱度增加而升高：区域与全球趋势的证据》 [https://doi.org/10.5061/dryad.qnk98sfqz]

## 数据与文件结构描述

本数据为Wyka等人的文章《地中海-撒哈拉过渡带中叶氮含量随干旱度增加而升高：区域与全球趋势的证据》所用数据。

### 文件与变量

#### 文件：README.md

**描述：** 本文件包含三个电子表格各自的变量列表。

#### 文件：Wyka_et_al._Morocco Raw data.xlsx

**描述：** 本数据集包含三个电子表格，标题分别为"Morocco raw data"、"Morocco species means"和"Press drying trial data"。

##### 变量：

1) 工作表“Morocco raw data”包含摩洛哥全境53个地点采集的单个叶片样本的位置数据、分类学信息、气候数据及叶性状测量值。列标题...