雅鲁藏布江巨柏种群分布格局及其对环境变化的响应

Distribution patterns of the Cupressus gigantea populations in the Yarlung Tsangpo River and their responses to environmental changes

利用点格局分析、相关分析、逐步回归的方法研究巨柏(Cupressus gigantea)种群的空间分布格局,分析不同尺度上巨柏种群分布格局的差异及其影响因子.结果表明巨柏种群的空间分布格局总体上以随机分布或集群分布为主,随着海拔、土壤养分、土壤质地等条件变化而变化.半阴坡低海拔种群分布格局在0.9~10.0 m尺度呈随机分布(P<0.05),在其他尺度呈集群或随机分布;中等海拔种群在2.8~10.0 m尺度呈集群分布(P<0.05),在其他尺度呈随机分布.阳坡低海拔种群在0.6~10.0 m尺度呈集群分布(P<0.05),在其他尺度呈随机分布.阴坡低海拔种群在0~10.0 m尺度均呈随机分布(P<0.05).半阳坡中等海拔种群在0~10.0 m尺度上均呈随机分布(P<0.05).尺度<5.0 m时,随着海拔梯度的升高,巨柏种群的聚集程度逐渐减弱;尺度>5.0 m时,海拔对巨柏种群分布的影响逐渐降低,土壤养分、土壤质地等因素的影响逐渐占据主导地位.不同尺度上巨柏种群分布格局受多种环境因子的影响,海拔和地形改变导致的小环境变化会显著影响巨柏种群的分布格局.在未来的巨柏保护中,应综合考虑环境因子的影响.

Plant population distribution pattern is one of the basic quantitative characteristics of plant population,and is of great significance to understand adaptation of plants to the environment by comprehensive influence of plant biological characteristics and environmental factors.In this paper,the spatial distribution pattern of the Cupressus gigantea population was studied by point pattern analysis,correlation analysis and stepwise regression methods,differences and influencing factors of C.gigantea population distribution patterns at different scales were analyzed.The spatial distribution pattern of C.gigantea population was found to be of mainly random distribution or cluster distribution,which changed with altitude,soil nutrients,texture and other conditions.The distribution pattern of low-altitude populations on semi-shady slopes was randomly distributed on the scale of 0.9-10.0 m(P<0.05),and clustered or randomly distributed on other scales.Medium-altitude populations are clustered on the 2.8-10.0 m scale(P<0.05)and randomly distributed on other scales.Low-altitude populations on sunny slope were clustered on the scale of 0.6-10.0 m(P<0.05)and randomly distributed on other scales.The low-altitude populations on slope with poor light were randomly distributed on the scale of 0-10.0 m(P<0.05).The medium-altitude population of slope with moderate light was randomly distributed on the scale of 0-10.0 m(P<0.05).On a scale of<5.0 m,the clustered degree of C.gigantea population gradually weakened with increased altitude,and when the scale was>5.0 m,the influence of altitude on the population distribution of C.gigantea gradually decreased,and influence of soil nutrients,soil texture and other factors gradually dominated.The distribution pattern of C.gigantea population at different scales is affected by a variety of environmental factors,and small environmental changes caused by altitude and topography changes will significantly affect the distribution pattern.In future protection of C.gigantea,influence of environmental factors should be comprehensively considered.