Kenya Long-term Exclosure Experiment (KLEE) read me. Site and data description

For a full site description, see Young et al. (1998). This manuscript is also included at the end of the “read me” document. KLEE was established in 1995 and consists of three replicate blocks, each containing six 200 x 200 m treatment plots. The replicate blocks are 70 – 200 m apart. The experiment uses semi-permeable barriers to allow access by different combinations of cattle (‘C’), mesoherbivore wildlife 15 – 1000 kg (‘W’) and megaherbivores (‘M’). Each of the following six treatments is replicated across the three blocks: C, W, WC, MW, MWC and O. The capital letters indicate which herbivores are allowed access (e.g., ‘O’ allows no herbivores >15 kg, ‘W’ allows mesoherbivore wildlife >15 kg, but no cattle or megaherbivores, and ‘MWC’ allows megaherbivores, mesoherbivore wildlife and cattle). Long-term patterns of dung deposition in the KLEE plots indicate that 1) treatments are >90% effective at excluding targeted species, and 2) experimental fences do not deter wild herbivores from using the plots intended to be accessible to them (see Young et al. 1998 for more details). Herded groups of 100-120 head of cattle are grazed in C, WC and MWC plots for several hours on each of two to three consecutive days, typically 3-4 times per year. The precise number of grazing days and timing of grazing largely depends on forage availability, but plots rarely experience more than 16 weeks without cattle grazing. This grazing regime reflects typical cattle management strategies for both private and communal properties in the region – where livestock graze in one general area for several days at a time until forage is depleted, then move on to a different area until the forage recovers. The landscape is not fenced into paddocks, but rather herders guide livestock so that the entire range undergoes similar episodic grazing throughout the year. The stocking rate of plots is similar to the moderate overall ranch stocking rate (0.10-0.14 cattle/ha; Odadi et al. 2007). Fire has not been an active part of this ecosystem since the 1960s (R.L. Sensenig, personal communication). Site description: The Kenya Long-term Exclusion Experiment (KLEE) is located at the Mpala Conservancy (3652’E, 017’N) in Laikipia County, Kenya. The study area is underlain with ‘black cotton’ soils, poorly drained vertisols with high (>50%) clay content (Ahn and Geiger 1987). Black cotton savannas are widespread in East Africa, covering hundreds of thousands of km2. Ninety-seven percent of the tree canopy cover in KLEE is Acacia drepanolobium Sjost. (Young et al. 1998), and total tree canopy cover averages 15-25%. Five grass species (Pennisetum mezianum Leeke, P. stramineum Peter, Themeda triandra Forssk., Lintonia nutans Stapf., and Brachiaria lachnantha (Hochst.) Stapf) make up 85% of herbaceous cover (Porensky et al. 2013). The site is located on virtually flat topography at an elevation of 1810m asl. The absence of distinct runoff or run-on areas, coupled with the relatively low plant diversity, makes this an ideal system to examine the effects of different herbivores on plant production independent of other factors.Mpala Conservancy is managed for both wildlife conservation and livestock production, with mean stocking rates of 0.10-0.14 cattle/ha. Wild ungulates commonly found at the study site include the mesoherbivores plains zebra (Equus burchelli Gray), Grant’s gazelle (Gazella [Nanger] grantii Brooke), hartebeest (Alcelaphus buselaphus Pallas), eland (Taurotragus oryx Pallas), and oryx (Oryx gazella beisa L.), as well as the megaherbivores elephant (Loxodonta africana Blumenbach), and reticulated giraffe (Giraffa camelopardalis L.). Total biomass-density (kg / km-2) of large wild ungulates is approximately one third of cattle biomass-density, and large wild ungulate biomass density is split almost evenly between megaherbivores and mesoherbivore wildlife (Veblen et al. 2016). In addition to these larger herbivores, one small antelope, steinbuck (Raphicerus campestris Thunberg), a strict browser, occurs in the area and is able to access all experimental treatment plots (Young et al. 2005). Wildlife in this region are present year-round and do not undergo large seasonal migrations. Descriptions of datasets available for download1. Rainfall 2. Dung3. Acacia drepanolobium density and size4. Plot locations5. Vegetation dataset Additional datasets available upon request 1. Rainfall Methods and description: Rainfall measurements were recorded from manual rain gauges located along the fence lines of KLEE. There are a total of three rain gauges. Each KLEE block has one manual rain gauge. Exact GPS locations are located in the “GPS locations” sheet of this document. Rainfall dates are recorded and gauge measurements are taken as soon as possible after rainfall events. This Excel worksheet has rainfall data from each of the three replicate KLEE blocks since 2003. There are separate worksheets for daily rainfall, monthly rainfall (since 1996), and yearly rainfall (since 1996). Additional monthly and yearly rainfall data since 1996 are available upon request. Measurements are taken in millimeters. Columns North, Central, and South refer to gauge readings taken in the north, central, and south blocks of KLEE. 2. Dung Methods and description: Starting in 2006, we have conducted biennial (roughly March and October) dung surveys along six-4 m x100 m permanent transects within each of the 18 KLEE plots and three control transects outside of the KLEE plots. This Excel worksheet features dung count data for each KLEE plot. Count data is broken down by herbivore species. To avoid recounting the same dung piles during subsequent surveys, we crush all recorded dung piles during each session. For animals that defecate in middens (such as steinbuck and Grant's gazelle), we used the number of dung pellets and differences in shape and color to estimate the number of separate defecation events. Dung piles for all major herbivore species could be positively identified to species in the field, with two exceptions. The dung of cattle and buffalo could not be distinguished, and we lumped them. The dung of plains and Grevy's zebras also could not be distinguished from each other; hence we grouped them as “zebra”. However, plains zebra far outnumber Grevy’s, so effectively we consider these to be plains zebra dung. 3. Acacia drepanolobium density and size survey Methods and description: A. drepanolobium makes up approximately 97% of the woody cover in this system. This Excel file contains Acacia drepanolobium density and size distributions in each of the of the 18 KLEE plots. Surveys were conducted in 2011. Trees were surveyed along three 4 m x 100 m transects within each KLEE plot. Each row represents data from one transect. Columns indicate experimental block, plot, number of trees in each of five size classes, and total number of trees for each transect. Additional data for non-drepanolobium woody species, as well as a newly updated 2015 tree survey, are available upon request. 4. Plot locations Methods and description: This zip file contains 18 .kml files. Each file corresponds with one KLEE plot and is named according to its block (first letter) and treatment (following letters). We collected GPS points from the corners of each of the 18 experimental plots using a Trimble Juno 3B GPS unit with meter-level accuracy. Points were imported into QGIS and used to created polygons of each experimental plot. Polygons were then saved as Google Earth .kml files. 5. Vegetation dataset Methods and description: Herbaceous vegetation in all 18 KLEE plots has been sampled biannually (in February and June) or annually (in June) since 1995. Sampling periods follow rainy periods that are similar in terms of average rainfall. Due to improvements in species identification, pre-1999 surveys are not fully comparable to later data. Each of the eighteen 4 ha KLEE treatment plots contains a central hectare that is divided into a 10 x 10 m grid of 100 sampling stations. Aerial plant cover and composition are assessed at these stations by counting the number of pins hit by each species over a ten-point pin frame (with vertical pins separated by 5 cm; maximum one hit per pin per species). All 100 grid points were sampled 1999-2005, and every fifth grid point (20 per plot) was sampled from 2006 to 2013 (see Fig. 2 for current vegetation sampling layout). This Excel datasheet contains vegetation data from 1999 – 2013. Later surveys have also been conducted and are available upon request.完整样地描述详见Young等人（1998）的研究，该手稿亦附于本"README"文档末尾。肯尼亚长期排除实验（Kenya Long-term Exclusion Experiment, KLEE）始建于1995年，包含3个重复样区，每个样区内设置6块200m×200m的处理样地；重复样区间距为70~200米。本实验采用半透性围栏，以实现不同组合的家畜（"C"，即牛）、15~1000kg的中型野生草食动物（mesoherbivore wildlife，"W"）以及巨型草食动物（megaherbivore，"M"）的准入控制。以下6种处理均在3个重复样区中重复设置：C、W、WC、MW、MWC及O。大写字母代表允许准入的草食动物类群：例如，"O"表示禁止所有>15kg的草食动物进入；"W"表示仅允许>15kg的中型野生草食动物进入，排除家畜与巨型草食动物；"MWC"则允许巨型草食动物、中型野生草食动物与家畜同时进入。KLEE样地中长期的粪便沉积模式表明：1）各处理对目标类群的排除效率均超过90%；2）实验围栏并未阻碍目标野生草食动物进入预设可准入的样地（详细信息详见Young等人1998年的研究）。 以100~120头为群的家畜牛群，会在C、WC及MWC样地中连续放牧2~3天，每天放牧数小时，通常每年进行3~4次。具体放牧天数与放牧时机主要取决于牧草可获得量，但样地极少出现连续16周以上无家畜放牧的情况。该放牧制度契合该地区私有与公有牧场的典型家畜管理策略：即家畜在某一区域连续放牧数日直至牧草耗尽，随后转移至其他区域，待牧草恢复后再行返回。该区域并未以围栏划分轮牧小区，而是由牧人引导家畜移动，使整片放牧区域全年均能接受相似的阶段性放牧。样地的载畜率与该区域中等规模牧场的平均载畜率（0.10~0.14牛/公顷；Odadi等人，2007）基本一致。自20世纪60年代起，火干扰便不再是该生态系统的活跃干扰因子（R.L. Sensenig，私人通信）。 ### 样地概况 肯尼亚长期排除实验（KLEE）位于肯尼亚莱基皮亚县的姆帕拉保护区（Mpala Conservancy，坐标：36°52′E，01°17′N）。研究区域的土壤为"黑棉土"，即排水不良的高黏土含量（>50%）变性土（vertisols）（Ahn与Geiger，1987）。黑棉土稀树草原广泛分布于东非地区，总面积达数十万平方千米。KLEE样地内97%的树冠盖度由灰背金合欢（*Acacia drepanolobium* Sjost.）构成（Young等人，1998），总树冠盖度平均为15%~25%。5种草本植物——梅氏狼尾草（*Pennisetum mezianum* Leeke）、稻草狼尾草（*P. stramineum* Peter）、黄背草（*Themeda triandra* Forssk.）、斜叶林芝草（*Lintonia nutans* Stapf.）及毛颖臂形草（*Brachiaria lachnantha* (Hochst.) Stapf）——占草本盖度的85%（Porensky等人，2013）。该样地地势近乎平坦，海拔为1810米。由于不存在显著的径流区与汇水区，加之植物多样性较低，本系统成为探究不同草食动物对植物生产力影响的理想研究对象，可有效排除其他因素的干扰。 姆帕拉保护区兼具野生生物保护与家畜生产双重管理目标，平均载畜率为0.10~0.14牛/公顷。研究区域常见的野生有蹄类动物包括：中型野生草食动物——平原斑马（*Equus burchelli* Gray）、葛氏瞪羚（*Gazella [Nanger] grantii* Brooke）、狷羚（*Alcelaphus buselaphus* Pallas）、大羚羊（*Taurotragus oryx* Pallas）及南非剑羚（*Oryx gazella beisa* L.）；以及巨型草食动物——非洲象（*Loxodonta africana* Blumenbach）与网纹长颈鹿（*Giraffa camelopardalis* L.）。大型野生有蹄类的总生物量密度（kg/km²）约为家畜生物量密度的1/3，且其生物量密度在巨型草食动物与中型野生草食动物之间的占比近乎均等（Veblen等人，2016）。除上述大型草食动物外，区域内还栖息着一种小型羚羊——小岩羚（*Raphicerus campestris* Thunberg），该物种为专性食叶动物，可自由出入所有实验处理样地（Young等人，2005）。该区域的野生生物全年均有分布，无大规模季节性迁徙现象。 ### 可下载数据集说明 1. 降雨数据 2. 粪便数据 3. 灰背金合欢密度与尺寸数据 4. 样地位置数据 5. 植被数据集 另有部分数据集可按需申请获取： 1. 降雨补充数据 #### 1. 降雨数据 **方法与说明**：降雨数据由沿KLEE围栏布设的人工雨量计采集。实验共设置3台雨量计，每个KLEE重复样区各布设1台。雨量计的精确GPS坐标详见本文档"GPS位置"工作表。降雨发生后需尽快记录降雨日期并读取雨量计数据。本Excel工作表包含2003年以来3个重复样区的降雨数据，其中分别设置了日降雨、月降雨（1996年起）及年降雨（1996年起）三个独立工作表。1996年以来的补充月降雨与年降雨数据可按需申请获取。数据单位为毫米。表格中的"North""Central""South"列分别对应KLEE北、中、南三个样区的雨量计读数。 #### 2. 粪便数据 **方法与说明**：自2006年起，我们每两年（大致为每年3月与10月）在18块KLEE样地内各布设6条4m×100m的永久样线，并在KLEE样地外设置3条对照样线，开展粪便调查。本Excel工作表包含各KLEE样地的粪便计数数据，且数据按草食动物物种分类统计。为避免后续调查中重复计数同一粪便堆，每次调查时均会将已记录的粪便堆碾碎。对于在粪堆（midden）排便的物种（如小岩羚与葛氏瞪羚），我们通过粪便颗粒数量、形状及颜色差异估算独立排便事件的次数。绝大多数大型草食动物的粪便均可在野外准确鉴定至物种水平，但存在两个例外：一是无法区分家畜牛与水牛的粪便，故将二者合并统计；二是无法区分平原斑马与细纹斑马的粪便，故将其合并为"斑马"类群。由于平原斑马的数量远多于细纹斑马，因此实际统计中默认此类粪便均来自平原斑马。 #### 3. 灰背金合欢密度与尺寸调查数据 **方法与说明**：灰背金合欢（*Acacia drepanolobium*）约占本研究区域木本植被盖度的97%。本Excel文件包含18块KLEE样地内灰背金合欢的密度与尺寸分布数据。调查于2011年开展，每块KLEE样地内布设3条4m×100m的样线进行木本植物调查。表格每一行对应一条样线的调查数据，列信息分别为实验样区、样地编号、5个尺寸等级的树木数量及单条样线的总树木数。另有非灰背金合欢木本物种数据及2015年更新的树木调查数据可按需申请获取。 #### 4. 样地位置数据 **方法与说明**：本压缩包包含18个.kml格式文件，每个文件对应一块KLEE样地，文件名由样区首字母与后续处理代码组成。我们使用Trimble Juno 3B型GPS设备（精度达米级）采集18块实验样地各角的GPS坐标，将坐标导入QGIS软件后生成各实验样地的多边形矢量图层，最终保存为谷歌地球（Google Earth）兼容的.kml格式文件。 #### 5. 植被数据集 **方法与说明**：自1995年起，我们每两年（2月与6月）或每年（6月）对18块KLEE样地的草本植被进行采样。采样时段均选在降雨季后，以保证各次采样的平均降雨条件相近。由于物种鉴定技术的改进，1999年之前的调查数据与后续数据不完全具有可比性。每块面积为4公顷的KLEE处理样地均包含中央1公顷区域，该区域被划分为10×10m的网格，共设置100个采样点。在每个采样点，使用10针式针框（垂直针间距为5cm，每根针对每个物种最多记录一次击中）统计各物种击中针的数量，以评估植物盖度与组成。1999~2005年，我们对全部100个网格点进行采样；2006~2013年，仅对每5个网格点中的1个（每块样地20个采样点）进行采样（当前植被采样布局详见图2）。本Excel数据表包含1999~2013年的植被数据，后续开展的调查数据可按需申请获取。