The effect of geographic range position on demographic variability in annual plants
The effect of geographic range position on demographic variability in annual plants
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DOI：
10.1111/j.1365-2745.2010.01782.x
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发表时间：
2011-03-01
影响因子：
5.5
通讯作者：
Venable, D. Lawrence
中科院分区：
文献类型：
--
作者：
Gerst, Katharine L.;Angert, Amy L.;Venable, D. Lawrence
1.丰富度中心模型预测，物种丰富度将从中心向地理范围的边缘下降。因此，我们预计与人口动态有关的变量，如人口密度和生殖产出，将从中心向边缘下降。然而，这种模式的证据是相互矛盾的，表明地理上的外围地点可能不是生态外围的。种群可以在范围边缘的适宜栖息地中繁衍生息，也可以在当地适应周边条件。这项研究考察了在13个物种的地理和气候范围内，一个地点的位置与一个共同地点--美国亚利桑那州图森市图马莫克山沙漠实验室的种群动态之间的关系。我们使用了25年的冬季一年生植物长期数据集的存活率、繁殖力、发芽率和种群密度数据，以确定距离范围中心的距离与种群动态之间是否存在关系。地理距离是通过确定从沙漠实验室到根据地点记录确定的观测范围中心的距离来计算的。使用生态位模拟软件MAXENT计算气候距离，并从沙漠实验室的气候剖面中减去物种范围的平均气候剖面。平均人口指标和距离指标之间没有关系。我们发现，一些地理距离度量与繁殖力、存活率和每萌发生殖力的差异之间存在显著的相关性，但与发芽率或种群密度的差异无关。我们没有发现与种群动态变化和气候距离的任何度量之间的关系。综合。我们的结果表明，与13种一年生植物范围中心的地理距离比气候距离更能预测它们的种群动态。这项研究强调了检查生命率及其变化的重要性，以便适当地捕捉一定范围内的位置对种群动态的影响。
1. The abundant centre model predicts that species abundance will decline from the centre towards the periphery of the geographic range. Thus, we expect to find decreases from the centre towards the edge in variables related to population dynamics such as population density and reproductive output. However, evidence for this pattern is contradictory, suggesting that geographically peripheral sites may not be ecologically peripheral. Populations may thrive in pockets of suitable habitat at the edge of the range or may be locally adapted to peripheral conditions.2. This study examines how the position of a site within geographic and climatic ranges of 13 species is related to the population dynamics at one common location, The Desert Laboratory at Tumamoc Hill, Tucson, AZ, USA.3. We used data on survival, fecundity, germination fraction and population density from a 25-year long-term data set on winter annual plants to determine whether there was a relationship between distance to the centre of the range and population dynamics. Geographic distance was calculated by determining the distance from the Desert Laboratory to the centre of the observed range determined from locality records. Climatic distance was calculated using the niche modelling software, MAXENT, and subtracting the mean climatic profile for the species range from that of the Desert Laboratory.4. There was no relationship between mean population metrics and distance metrics. We found significant relationships between some geographic distance metrics and variance in fecundity, survival and per-germinant fecundity, but not germination fraction or population density. We did not find a relationship with any metric of population dynamic variation and climatic distance.5. Synthesis. Our results indicate that geographic distance from the centre of the range of 13 annual plant species more strongly predicts their population dynamics than climatic distance. This study reinforces the importance of examining vital rates and their variation in order to properly capture the effect of position within a range on population dynamics.