TY - JOUR
T1 - Genetic factors associated with population size may increase extinction risks and decrease colonization potential in a keystone tropical pine
AU - Del Castillo, Rafael F.
AU - Trujillo-Argueta, Sonia
AU - Sánchez-Vargas, Nahúm
AU - Newton, Adrian C.
PY - 2011/7
Y1 - 2011/7
N2 - Pioneer species are essential for forest regeneration and ecosystem resilience. Pinus chiapensis is an endangered pioneer key species for tropical montane cloud forest regeneration in Mesoamerica. Human activities have severely reduced some P. chiapensis populations, which exhibited a small or null colonization potential suggesting the involvement of genetic factors associated with small populations. We explored the relationships between (i) population genetic diversity (allozymes) and population size, including sampling size effects, (ii) fitness estimates associated with colonization potential (seed viability and seedling performance) in a common environment and population size, and (iii) fitness estimates and observed heterozygosity in populations with sizes spanning five orders of magnitude. All the estimates of genetic diversity and fitness increased significantly with population size. Low fitness was detected in progenies of small populations of disturbed and undisturbed habitats. Progenies with the lowest observed heterozygosity displayed the lowest fitness estimates, which, in turn, increased with heterozygosity, but seed viability peaked at intermediate heterozygosity values suggesting inbreeding and outbreeding depression. Inbreeding depression appears to be the most immediate genetic factor in population decline. Conservation efforts should try to maintain large and genetically diverse populations, enhance gene flow by restoring connectivity between adjacent populations, and avoid genetically distant individuals.
AB - Pioneer species are essential for forest regeneration and ecosystem resilience. Pinus chiapensis is an endangered pioneer key species for tropical montane cloud forest regeneration in Mesoamerica. Human activities have severely reduced some P. chiapensis populations, which exhibited a small or null colonization potential suggesting the involvement of genetic factors associated with small populations. We explored the relationships between (i) population genetic diversity (allozymes) and population size, including sampling size effects, (ii) fitness estimates associated with colonization potential (seed viability and seedling performance) in a common environment and population size, and (iii) fitness estimates and observed heterozygosity in populations with sizes spanning five orders of magnitude. All the estimates of genetic diversity and fitness increased significantly with population size. Low fitness was detected in progenies of small populations of disturbed and undisturbed habitats. Progenies with the lowest observed heterozygosity displayed the lowest fitness estimates, which, in turn, increased with heterozygosity, but seed viability peaked at intermediate heterozygosity values suggesting inbreeding and outbreeding depression. Inbreeding depression appears to be the most immediate genetic factor in population decline. Conservation efforts should try to maintain large and genetically diverse populations, enhance gene flow by restoring connectivity between adjacent populations, and avoid genetically distant individuals.
KW - Colonization
KW - Conservation
KW - Fitness
KW - Genetic variation
KW - Inbreeding depression
KW - Outbreeding depression
KW - Pinus chiapensis
KW - Population size
KW - Restoration
KW - Tropical montane cloud forest
UR - http://www.scopus.com/inward/record.url?scp=79958818237&partnerID=8YFLogxK
U2 - 10.1111/j.1752-4571.2010.00177.x
DO - 10.1111/j.1752-4571.2010.00177.x
M3 - Artículo
AN - SCOPUS:79958818237
SN - 1752-4563
VL - 4
SP - 574
EP - 588
JO - Evolutionary Applications
JF - Evolutionary Applications
IS - 4
ER -