TY - JOUR
T1 - Effect of patch size and isolation on mating patterns and seed production in an urban population of Chinese pine (Pinus tabulaeformis Carr.)
AU - Wang, Hongfang
AU - Sork, Victoria L.
AU - Wu, Jianguo
AU - Ge, Jianping
N1 - Funding Information:
We thank Dayong Zhang, Xiao Chen, Douglas Scofield, Peter Smouse, Mauricio Quesada, Pamela Thompson, Keith Gaddis, Weining Bai and Tianming Wang for their kind comments and suggestions on the manuscript. Specially thank Shen Zhao, Xiaopeng Sun and many others friends for helping data collections. We also thank the two anonymous reviewers and the editor for their substantial suggestions on improving the manuscript. The work was supported by the “China National Scientific and Technical Foundation Project” (Grant No. 2006FY210100 ). VLS was supported by the National Science Foundation ( NSF-DEB-0516529 ).
PY - 2010/8
Y1 - 2010/8
N2 - Fragmentation is a critical issue for tree populations because the creation of small patches can reduce local population size and increase isolation, both of which can promote inbreeding and its negative consequences, as well as loss of genetic diversity. To test the hypothesis that patch size and isolation influence mating patterns or seed production in forest trees, we utilize the spatial array of trees of an urban population of Chinese Pine (Pinus tabulaeformis Carr.) planted in patches around Beijing. Our design includes 28 urban patches, with patch size ranging from 1 to 2000 adult trees and isolation (edge distance index) ranging from 37.5m to 245.8m. We examined the average number of seeds per cone and percentage of viable seed per cone for each patch as measures of seed production. By utilizing seven paternally inherited chloroplast microsatellite loci, we estimated the mating pattern parameters for each patch, including the level of selfing, the amount of immigrant pollen and the effective number of pollen sources (Nep). Using a general linear model selection procedure based on AIC value, we found patch size was the best predictor of the selfing and immigration rate; smaller patches had a higher selfing and immigration rate. Small patches with one adult had relatively high Nep which indicates connectivity among urban patches. However, due to the reduced amount of immigrant pollen and limited diversity of local pollen, intermediate sized patches (with 5-10 adults) had the lowest Nep among the study patches. For patches with more than 10 adults, Nep was increased with patch size. The percentage of viable seeds per cone significantly decreased with patch size, indicating a possible negative consequence of inbreeding. The effect of patch size on mating patterns and seed production suggests that the patches of trees experience less connectivity than trees within continuous forest. These findings indicate that forest management practices should emphasize the maintenance of an optimal patch size because, despite the fact that tree species show the potential for long distance pollen movement, the number of local trees strongly influences the mating patterns.
AB - Fragmentation is a critical issue for tree populations because the creation of small patches can reduce local population size and increase isolation, both of which can promote inbreeding and its negative consequences, as well as loss of genetic diversity. To test the hypothesis that patch size and isolation influence mating patterns or seed production in forest trees, we utilize the spatial array of trees of an urban population of Chinese Pine (Pinus tabulaeformis Carr.) planted in patches around Beijing. Our design includes 28 urban patches, with patch size ranging from 1 to 2000 adult trees and isolation (edge distance index) ranging from 37.5m to 245.8m. We examined the average number of seeds per cone and percentage of viable seed per cone for each patch as measures of seed production. By utilizing seven paternally inherited chloroplast microsatellite loci, we estimated the mating pattern parameters for each patch, including the level of selfing, the amount of immigrant pollen and the effective number of pollen sources (Nep). Using a general linear model selection procedure based on AIC value, we found patch size was the best predictor of the selfing and immigration rate; smaller patches had a higher selfing and immigration rate. Small patches with one adult had relatively high Nep which indicates connectivity among urban patches. However, due to the reduced amount of immigrant pollen and limited diversity of local pollen, intermediate sized patches (with 5-10 adults) had the lowest Nep among the study patches. For patches with more than 10 adults, Nep was increased with patch size. The percentage of viable seeds per cone significantly decreased with patch size, indicating a possible negative consequence of inbreeding. The effect of patch size on mating patterns and seed production suggests that the patches of trees experience less connectivity than trees within continuous forest. These findings indicate that forest management practices should emphasize the maintenance of an optimal patch size because, despite the fact that tree species show the potential for long distance pollen movement, the number of local trees strongly influences the mating patterns.
KW - AIC
KW - Fragmentation
KW - General linear model
KW - Paternity analysis
KW - Pinus tabulaeformis
KW - Urban landscape
UR - http://www.scopus.com/inward/record.url?scp=77955516446&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77955516446&partnerID=8YFLogxK
U2 - 10.1016/j.foreco.2010.06.014
DO - 10.1016/j.foreco.2010.06.014
M3 - Article
AN - SCOPUS:77955516446
SN - 0378-1127
VL - 260
SP - 965
EP - 974
JO - Forest Ecology and Management
JF - Forest Ecology and Management
IS - 6
ER -