鹫峰国家森林公园残次林物种多样性及生态位特征

残次林作为低效林的一种，林相及生态稳定性较差，造成景观差、生态功能低下。本文利用样地调查方法，对鹫峰森林公园主要残次林群落及不同立地条件下物种多样性进行分析，同时计算群落内优势种群生态位，旨在通过研究其生态系统的结构与功能，为提出林相改造技术提供科学依据。结果表明：（1）鹫峰国家森林公园残次林各群落多样性指数：油松林>刺槐林>五角枫、山桃混交林>荆条灌草林>侧柏林>栓皮栎林。（2）在不同的立地条件下，残次林的分布的影响较为明显，乔木层和草本层多样性指数呈现阴坡>半阴半阳坡>阳坡，厚土层>薄土层，而灌木层受坡向与土壤状况影响不明显。（3）鹫峰残次林的典型特点为林草匮乏，表现为乔木层破败、草本层覆盖度低种群分化。（4）生态位较宽的种群之间有可能具有较高重叠程度，但重叠程度不一定随宽度值增大而增大，分布频度是影响物种重叠程度的重要因素。该研究说明残次林与普通林物种多样性相比有很大的差别，且各林分残次程度不一，分化严重，物种单一和恶劣的立地条件是产生残次林的主要原因。

Species Diversity and Niche Characteristics of Defective Forest in Jiufeng National Forest Park

As a low- efficiency forest, defective forest has worse forest form and ecological stability, resulting in poor landscape and ecological function. By sample-plot survey method, we analyzed the main defective communities forest and the species diversity in different site conditions of Jiufeng Forest Park for the forest form transformation technology after studying its structure and function of ecosystems. The defective degree of each community type of defective forest in Jiufeng National Forest Park was different, the order of species diversity was as follows: Chinese pine plantation>Robinia pseudoacacia plantation>Acer mono and Prunus mixed plantation>Shrub and grass plantation>Oriental Arborvitae plantation>Quercus variabilis plantation. In different site, in terms of the distribution of defective forest, the impacts of slope and soil conditions is more obvious, and the order of species diversity were slope>semi-shady slope>sunny, thick soil layer>thin soil, with the non-obvious effects in shrub layer. The typical characteristics of Jiufeng defective forest is lack of trees and grass, and in the specific performance the forest form of tree layer is dilapidated and herb layer coverage is low population differentiation. The population with wider niche may have a higher degree of overlaps, however, this situation is not certain, and the frequency distribution is an important factor affecting the degree of overlap of species. Therefore, the diversity of relict forest species has great difference with common forest species, and the different stand of the defective degree, serious differentiation, single species and poor site conditions are the main reasons for the formation of relict forest.