Data from: Reproductive success, fruit removal and local distribution patterns in the early-flowering shrub Daphne mezereum

This is the data from the article 
Reproductive success, fruit removal and local distribution patterns in the early-flowering shrub Daphne mezereum
(DOI: XXXXXX)

Matilda Arnell, Ove Eriksson and Johan Ehrlén

DESCRIPTION
In this study we mapped the spatial distribution of individuals in a population of the early flowering, fleshy-fruited shrub Daphne mezereum, in a forest in boreo-nemoral Sweden for three consecutive years (2016-2018). For all mapped individuals we collected data on numbers of flowers and fruits and fruit removal. In one year, 2019, we also performed a hand pollination experiment. 

We analyzed spatial associations among individuals, and the effects on reproductive performance and fruit removal of plant height, numbers of flowers and fruits, distance to forest edge, and neighboring flower and fruit density.

The data includes:
An R-script to perform analyses included in the article
       Arnell_2023_script.R

Spatial locations, reproductive status (vegetative / reproductive) and plant height of all individuals of D. mezereum in the local population in 2016-2017
        daphne_16.csv
        daphne_17.csv       
        daphne_18.csv

Data on number of flowers, number of fruits, fruit removal, plant height, flowers and fruits on neighboring reproductive individual within a 10 m radius of each reproductive individual and the distance to forest edges for each reproductive individual in 2016-2018
        reproductive_16.csv
        reproductive_17.csv       
        reproductive_18.csv

Data on flower gender (hermaphroditic/female) and fruit set for a subset of the local population in 2016-2018
        pollination_16.csv
        pollination_17.csv       
        pollination_18.csv

Results from the hand pollination experiment for a subset of the local population in 2019
        pollination_19.csv

Size of the study area and the length and location of forest edges (shapefiles) used in the analyses of spatial associations in R (each shapefile consists of six files with the extensions: .cpg, .dbf, .prj, .sbn, .sbx, .shp, .shx, and can be opened in R or any GIS prgram such as the open source software QGIS) 
         win.shp 
         lines.shp

Please refer to the README-files for further information about each data set / item.

STUDY SPECIES
Daphne mezereum is a deciduous shrub that can grow up to a height of 200 cm. In Sweden, D. mezereum is a relatively rare species found mainly on damp, humus-rich soils at forest edges or in deciduous forests previously managed as meadows or grazed by livestock. D. mezereum is one of the earliest species to flower in this region. Flowers are usually open from April to May, although during mild winters the onset of flowering can be as early as February.

LOCATION
This study was carried out on the peninsula of Väddö in the Stockholm archipelago in south eastern Sweden. The study area covers approximately 4.8 hectares, largely located in a forest. In the area, the forest is dominated by Picea abies, with deciduous species (e.g. Betula spp. and Populus tremula) occurring mostly in forest edges and in forest gaps. The soil consists of glacial till influenced by nearby occurring calcareous bedrock. The mean temperature of January is -3.5 C° and the mean temperature for June is -15.9 C°, with a mean annual precipitation of 595 mm.

FIELD SURVEY
During the years 2016-2018, we mapped all established individuals of D. mezereum of approximately 10 cm and higher within the study area. Individuals that were not detected during the first year were added continuously the following years of survey. In late April to early May we recorded the number of buds and flowers on each individual, as well as plant height. We recorded the number of fruits in June to August.

In 2019, to investigate if individuals were pollen limited, we surveyed 70 reproductive individuals. For each individual we recorded if flowers were hermaphroditic or female (anthers without pollen or lacking anthers). On individuals with more than one branch, we performed a cross-pollination experiment. One branch was pollinated and the rest was left un-treated as control. Pollen was taken from three or more randomly selected plants not included in the survey and applied with a small brush into each flower tube, on both hermaphroditic and female flowers. In April to May, we recorded number of flowers and in June the number of developing fruits.

POLLINATION AND FRUIT SET
To estimate the degree of pollen limitation, we compared fruit set between individuals having hermaphroditic flowers (producing pollen) and individuals having female flowers (producing no pollen), and assessed the effect of the pollen-addition treatment on fruit set.

SPATIAL ASSOCIATIONS
To describe the spatial structure of the population, we estimated spatial associations among individuals of D. mezereum based on the spatial locations of all individuals in the three survey years. Spatial associations were estimated using the inhomogeneous pair correlation function ginhom(r). Spatial associations among individuals with the same reproductive status (reproductive/vegetative) were also estimated separately. 
To describe the spatial structure of the population in relation to landscape structures, we fitted an inhomogeneous Thomas cluster process, with distance to forest edge (distance to edge) as a covariate. 

INVESTMENT IN REPRODUCTION, REPRODUCTIVE SUCCESS AND DISPERSAL IN RELATION TO DISPERSAL TRAITS AND DISTRIBUTION PATTERNS
We considered six predictor variables when investigating the effects of plant traits and distribution patterns on number of flowers (investment in reproduction), fruit set (relative reproductive success) and fruit removal. The predictors included three traits, height, number of flowers and number of fruits, and three measures of spatial locations, distance to forest edge, total number of flowers within a 10 m radius (neighboring flower density) and total number of fruits within a 10 m radius (neighboring fruit density). We chose a radius of 10 m as the analyses of spatial associations showed positive spatial associations up to 10 m.

The effect of three variables (height, distance to edge, neighboring flower density) were included in the model explaining the number of flowers produced by individuals of D. mezereum.

The effect of four variables (height, flowers, distance to edge, neighboring flower density) were included in the model explaining the fruit set of individuals of D. mezereum.

The effect of four variables (height, fruits, distance to edge, neighboring fruit density) were included in the model explaining the fruit removal in individuals of D. mezereum.

Please consult the original article as well as the R-script "Arnell_2023_script.R" for details on how the data was analyzed. 

Please contact Matilda Arnell ([e-mail]) for information or collaboration. 

Please cite the original article when using these data (DOI: XXXXX).

本数据集源自于论文《早花肉质灌木欧丁香（Daphne mezereum）的繁殖成功、果实移除及局部分布模式》（DOI: XXXXXX）。

研究描述如下：

本研究历时三年（2016-2018年）对瑞典北方针叶林中早花肉质果灌木欧丁香的种群个体空间分布进行了测绘。对于所有测绘的个体，我们收集了花朵和果实的数量以及果实移除情况。在2019年，我们进行了一项手授粉实验。

我们分析了个体间的空间关联，以及植物高度、花朵和果实的数量、距离森林边缘的距离以及邻近个体的花朵和果实密度对繁殖表现和果实移除的影响。

数据包括：

* 用于执行论文中包含分析的 R 脚本：Arnell_2023_script.R

* 2016-2017年本地种群中所有欧丁香个体的空间位置、繁殖状态（营养生长/繁殖生长）和植物高度：daphne_16.csv、daphne_17.csv、daphne_18.csv

* 2016-2018年每个繁殖个体10米半径内邻近繁殖个体的花朵和果实数量，以及每个繁殖个体到森林边缘的距离：reproductive_16.csv、reproductive_17.csv、reproductive_18.csv

* 2016-2018年本地种群子集的花朵性别（雌雄同体/雌性）和果实结实情况：pollination_16.csv、pollination_17.csv、pollination_18.csv

* 2019年本地种群子集手授粉实验的结果：pollination_19.csv

* 研究区域的大小、森林边缘的长度和位置（用于 R 中空间关联分析的 shapefiles，每个 shapefile 包含六个文件，扩展名为：.cpg、.dbf、.prj、.sbn、.sbx、.shp，可在 R 或任何 GIS 软件中打开，如开源软件 QGIS）：win.shp、lines.shp

请参考每个数据集/项目的 README 文件以获取更多信息。

研究物种：欧丁香（Daphne mezereum）是一种高达 200 厘米的落叶灌木。在瑞典，欧丁香是一种相对稀少的物种，主要分布在湿润、富含腐殖质的土壤上，位于森林边缘或过去作为草地管理的落叶林或被牲畜放牧的森林中。欧丁香是该地区最早开花的物种之一。花朵通常从四月到五月开放，但在温和的冬季，开花可能最早在二月。

地点：本研究在瑞典东南部斯德哥尔摩群岛的韦德岛半岛上进行。研究区域大约 4.8 公顷，主要位于森林中。在该区域，森林主要由欧洲赤松组成，落叶树种（例如 Betula spp. 和 Populus tremula）主要出现在森林边缘和森林空地。土壤由受附近石灰岩基底影响的冰川沉积物组成。一月份的平均温度为 -3.5°C，六月份的平均温度为 -15.9°C，年平均降水量为 595 毫米。

实地调查：在 2016-2018 年期间，我们在研究区域内测绘了约 10 厘米及以上的所有欧丁香个体。在第一年未发现的个体在后续调查年份中持续添加。在四月底到五月初，我们记录了每个个体的芽和花朵数量，以及植物高度。在六月到八月期间，我们记录了果实数量。

在 2019 年，为了调查个体是否受花粉限制，我们对 70 个繁殖个体进行了调查。对于每个个体，我们记录了花朵是雌雄同体还是雌性（雄蕊无花粉或无雄蕊）。对于有多于一个分支的个体，我们进行了一项杂交授粉实验。一个分支被授粉，其余的作为对照未处理。花粉从三个或更多随机选择的、不包括在调查中的植物中取出，并用小刷子应用于每个花朵的花管中，无论是雌雄同体还是雌性花朵。在四月到五月期间，我们记录花朵数量，在六月记录正在发育的果实数量。

授粉和果实结实情况：为了估计花粉限制的程度，我们比较了具有雌雄同体花朵（产生花粉）的个体与具有雌性花朵（不产生花粉）的个体的果实结实情况，并评估了花粉添加处理对果实结实的影响。

空间关联：为了描述种群的空间结构，我们根据三年调查中所有个体的空间位置估计了 D. mezereum 个体间的空间关联。空间关联使用非齐次成对相关函数 ginhom(r) 进行估计。对于具有相同繁殖状态（繁殖/营养生长）的个体，也分别估计了空间关联。

为了描述与景观结构相关的种群空间结构，我们拟合了一个非齐次托马斯集群过程，将距离森林边缘的距离（距离边缘）作为协变量。

关于繁殖投资、繁殖成功和扩散与扩散特性和分布模式的关系：在研究植物特性和分布模式对花朵数量（繁殖投资）、果实结实情况（相对繁殖成功）和果实移除的影响时，我们考虑了六个预测变量。预测变量包括三个特性，即高度、花朵数量和果实数量，以及三个空间位置度量，即距离森林边缘的距离、10 米半径内的总花朵数量（邻近花朵密度）和10 米半径内的总果实数量（邻近果实密度）。我们选择 10 米作为分析半径，因为空间关联分析显示空间关联在 10 米范围内呈正。

将三个变量（高度、距离边缘、邻近花朵密度）纳入解释 D. mezereum 个体产生花朵数量的模型中。

将四个变量（高度、花朵、距离边缘、邻近花朵密度）纳入解释 D. mezereum 个体果实结实情况的模型中。

将四个变量（高度、果实、距离边缘、邻近果实密度）纳入解释 D. mezereum 个体果实移除的模型中。

请参考原始文章以及 R 脚本 'Arnell_2023_script.R' 以获取关于数据如何分析的详细信息。

如需信息或合作，请联系 Matilda Arnell（[e-mail]）。

在引用这些数据时，请引用原始文章（DOI: XXXXX）。