Reproductive investment of <Emphasis Type="Italic">Pinus pseudostrobus</Emphasis> along an altitudinal gradient in Western Mexico: implications of climate change |
| |
| Authors: | Leonel Lopez-Toledo Margarita Heredia-Hernández Dante Castellanos-Acuña Arnulfo Blanco-García Cuauhtémoc Saénz-Romero |
| |
| Institution: | 1.Instituto de Investigaciones sobre los Recursos Naturales,Universidad Michoacana de San Nicolás de Hidalgo,Morelia,Mexico;2.Instituto de Investigaciones Agropecuarias y Forestales,Universidad Michoacana de San Nicolás de Hidalgo,Morelia,Mexico;3.Department of Renewable Resources, Faculty of Agricultural, Life, and Environmental Sciences,University of Alberta,Edmonton,Canada;4.Facultad de Biología,Universidad Michoacana de San Nicolás de Hidalgo,Morelia,Mexico |
| |
| Abstract: | Climate varies along altitudinal gradients and species performance may be affected in response to these variations. Climate change can modify these gradients and, at the lower limit of species distributions, individuals may become stressed and their general health and reproductive performance may decrease. Study and prediction of the effects of climate change on the distribution of species along these gradients is therefore necessary. Our model study species, Pinus pseudostrobus, is a widely distributed pine in Mexico, ranging from 1600 to 3200 masl in altitude. In order to explore changes in health condition and reproductive investment along an altitudinal gradient, ten reproductive trees were selected in each of four populations (at 2300, 2400, 2700 and 2900 masl). As a proxy of individual health, we conducted a rapid visual assessment for each tree, based on crown defoliation, dead branches and foliage discoloration. This stress condition index (SCI) ranges from zero to fifteen, and lower values indicate low stress and therefore better health conditions. We also evaluated reproductive (cone weight, number/weight of seeds) and progeny (germination/seedling growth) traits. In addition, the relationships between SCI and the reproductive/progeny traits were assessed. The lowest altitude population presented poor health, with higher values of SCI (mean ± SE = 6.3 ± 0.9) that reduced up to 4.8-fold in higher-altitude populations. Cone weight also differed among altitudes, with lighter cones in the lower population (mean ± SE = 38.2 ± 4.3 g), and 1.5-fold heavier cones found in the higher populations. In general, all of the reproductive/progeny traits differed among altitudes. The population of intermediate altitude (2700 masl) presented the highest values for all traits evaluated, indicating higher performance at this altitude. Finally, a negative relationship was found between stress condition and cone weight. Based on our results and climate change models and their predictions, an increase in physiological stress can be expected in individuals of low altitude populations. Furthermore, possible increases in pests and pathogens are likely to contribute to the decline of this population. It is therefore necessary to maintain efforts of stress condition assessment and population dynamics, as well as to permanently monitor the climate along altitudinal gradients. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
