Demography of American black bears (Ursus americanus) in a semiarid environment

The American black bear (Ursus americanus) has one of the broadest geographic distributions of any mammalian carnivore in North America. Populations occur from high to low elevations and from mesic to arid environments, and their demographic traits have been documented in a wide variety of environments. However, the demography of American black bears in semiarid environments, which comprise a significant portion of the geographic range, is poorly documented. To fill this gap in understanding, we used data from a long-term mark-recapture study of black bears in the semiarid environment of eastern Utah, USA. Cub and yearling survival were low and adult survival was high relative to other populations. Adult life stages had the highest reproductive value, comprised the largest proportion of the population, and exhibited the highest elasticity contribution to the population growth rate (i.e., λ). Vital rates of black bears in this semiarid environment are skewed toward higher survival of adu..., Mark-Recapture study
We estimated survival rates from long-term mark-recapture data gathered as part of a 27-year study on American black bears of the East Tavaputs Plateau. During the first 12 years of the study (June to August 1991-2003) female bears were captured and radio-collared, and all bears were tagged in the ear, except for cubs and yearlings. For the entire study (1992 – 2019), collared females were visited in their dens annually during their winter hibernation to count newborn cubs and surviving yearlings. Age of individual bears was determined by 2 methods: (1) direct observation of cubs or yearlings (i.e., year of birth was known) or (2) cementum annuli analysis of a cross-section of the root of an extracted premolar (Palochak, 2004; Willey, 1974).
The data we used to derive survival and fecundity rates consisted of the ID_number, cohort (cub, yearling, subadult, prime-aged adult, and old adult), age in years, sex (female, male, unknown), number of cubs, number of yearling..., , # Demography of American black bears (Ursus americanus) in a semiarid environment

[https://doi.org/10.5061/dryad.98sf7m0t8](https://doi.org/10.5061/dryad.98sf7m0t8)

## Description of the data and file structure

### Files and variables

#### File: Age-Specific\_Survivorship.csv

**Description:** 

This CSV file contains data collected from a mark-recapture study during 1991 - 2019. We calculated the age-specific average survival rate for each cohort. The average survival rate of each cohort was later used in the matrix transition model as matrix elements to retrieve important demographic information about this population of North American black bears (*Ursus americanus*) found in a semiarid environment. 

##### Variables

* Cohort: Yearling = 1 year to 2 years; Subadult = 2 years to 4 years; Prime-aged Adult = 4 years to 14 years; Old Adult = 15 years and older.
* Sex: M = male; F = female; U = unknown
* Cubs and Yearlings: NV = not visited; number = number of cubs or yearlings presen...

美洲黑熊（Ursus americanus）是北美分布范围最广的食肉哺乳动物之一。其种群栖息于从高海拔到低海拔、从湿润到干旱的各类生境，且其种群动态特征已在多种环境中得到研究记录。然而，占其地理分布范围相当比例的半干旱生境中的美洲黑熊种群动态，却鲜有详实记载。为填补这一研究空白，我们利用美国犹他州东部半干旱生境中开展的美洲黑熊长期标记重捕研究数据开展分析。相较于其他种群，该区域黑熊的幼崽和1龄熊存活率较低，而成体存活率较高。成体生命阶段具有最高的繁殖价值，在种群中占比最大，且对种群增长率（即λ）的弹性贡献最高。该半干旱生境中美洲黑熊的种群生命率偏向于成体更高的存活率……
标记重捕研究
本研究基于美国犹他州东部塔瓦普茨高原东部的一项为期27年的美洲黑熊长期标记重捕研究获取的数据，估算了种群存活率。在研究的前12年（1991-2003年的6月至8月），研究人员捕捉雌性黑熊并为其佩戴无线电项圈，除幼崽和1龄熊外，所有个体均进行耳标标记。在整个研究周期（1992-2019年）内，研究人员于每年冬季冬眠期对佩戴项圈的雌性黑熊的巢穴进行走访，以统计新生幼崽和存活的1龄熊数量。个体黑熊的年龄通过两种方法确定：（1）直接观测幼崽或1龄熊（即已知其出生年份）；（2）对拔除的前臼齿牙根横截面进行牙骨质环分析（Palochak, 2004; Willey, 1974）。
本研究用于推导存活率和繁殖率的数据包含：个体编号、年龄组（幼崽、1龄熊、亚成体、壮年成体、老年成体）、年龄（岁）、性别（雌性、雄性、未知）、幼崽数量、1龄熊数量……
# 半干旱生境中美洲黑熊（Ursus americanus）的种群动态
[https://doi.org/10.5061/dryad.98sf7m0t8](https://doi.org/10.5061/dryad.98sf7m0t8)
## 数据与文件结构说明
### 文件与变量
#### 文件：Age-Specific_Survivorship.csv
**描述：**
本CSV文件包含1991-2019年标记重捕研究中采集的数据。研究人员为每个年龄组计算了年龄特异性平均存活率，后续将各年龄组的平均存活率作为矩阵元素代入矩阵转移模型，以获取该半干旱生境中北美黑熊（*Ursus americanus*）种群的关键种群动态信息。
##### 变量说明
* 年龄组（Cohort）：1龄熊（Yearling）= 1~2岁；亚成体（Subadult）= 2~4岁；壮年成体（Prime-aged Adult）= 4~14岁；老年成体（Old Adult）= 15岁及以上。
* 性别（Sex）：M=雄性；F=雌性；U=未知
* 幼崽与1龄熊数量（Cubs and Yearlings）：NV=未走访；number=当前存在的幼崽或1龄熊数量……