南方红壤区3种典型森林恢复方式对植物群落多样性的影响

合理的森林恢复方式能提高植物多样性,进而提高生态系统服务功能.在我国南方红壤区研究了3种典型森林恢复方式(引进种恢复的湿地松(Pinus elliottii)人工林本地种恢复的马尾松(Pinus massoniana)人工林和自然恢复的天然次生林)的植物区系构成和植物群落多样性.结果表明:(1)湿地松人工林有155种植物,隶属66科118属,马尾松人工林有137种植物,隶属59科97属；天然次生林有226种植物,隶属86科160属,3种森林恢复方式的乔木层、灌木层和草本层的优势科属明显不同,马尾松人工林的优势物种和天然次生林更相似；(2)天然次生林的植物区系基本构成、植物区系类型种类高于马尾松人工林和湿地松人工林,并且天然次生林的温带成分比例高于湿地松人工林；(3)恢复方式对植物群落的多样性指数有显著影响,天然次生林的物种丰富度、辛普森指数明显高于马尾松人工林和湿地松人工林,两种人工林之间差异不显著；(4)3种森林恢复方式的植物群落结构存在显著差异,相比湿地松人工林,马尾松人工林的植物群落组成与天然次生林更相似.总之,自然恢复的天然次生林植物群落多样性高于人工恢复的马尾松人工林和湿地松人工林,本地种马尾松人工林在维持区域植物群落结构功能上优于引进种湿地松人工林.

Effects of three forest restoration approaches on plant diversity in red soil region, southern China

Plant diversity has important ecosystem function in forest ecosystem. Forest restoration approaches can impact plant diversity, especially the understory plant diversity. We studied the floristic characteristics, plant community structure and diversity of three forest restoration approaches in red soil region of southern China, which included introduced species slash pine (Pinus elliottii) plantations, native species Masson pine (Pinus massoniana) plantations and natural secondary forests. For each forest restoration approach, a total of 15 independent plots were surveyed. On each plot, three 10 m × 10 m subplots of area were surveyed for trees' abundance, height and diameter at breast height. Within each tree subplot, one to two shrub quadrates (5 m × 5 m) and one to three herb quadrates (1 m × 1 m) were surveyed for plant species abundance. A total of 127 tree subplots, 238 shrub subplots and 357 herb subplots were effectively surveyed for plant community structure. The results showed that: (1) 155 species (which belong to 160 genera and 86 families), 137 species (which belong to 97 genera, 59 families) and 226 species (which belong to 160 genera, 86 families) were identified in slash pine plantations, Masson pine plantations and natural secondary forests, respectively. Dominant species in these 3 forest restoration approaches varied in tree, shrub and herb layers. Dominant species in Masson pine plantations were more similar to that of natural secondary forests compared with that of slash pine plantations. In tree layer, the dominant plant in slash pine plantations was only P. elliotti. Similarly, the dominant plant in Masson pine plantations was only P. massoniana. The dominant species in natural secondary forests belong to Fagaceae, Lauraceae and Theaceae. In shrub layer, the dominant plants were Verbenaceae, Gramineae, Hamamelidaceae, Theaceae and Euphorbiaceae for slash pine plantations; Hamamelidaceae, Verbenaceae, Theaceae, Fagaceae and Myrtaceae for Masson pine plantations; Fagaceae, Hamamelidaceae, Theaceae, Rosaceae, Rubiaceae and Myrtaceae for natural secondary forest. In herb layer, the dominant plants were Gramineae, Gleicheniaceae and Thelypteridaceae for slash pine plantations; Gleicheniaceae, Hamamelidaceae, and Dryopteridaceae for Masson pine plantations; Myrsinaceae, Gramineae, Dryopteridaceae, Cyperaceae and Rubiaceae for natural secondary forests; (2) natural secondary forests had more flora types (21 flora types) than Masson pine plantations (16 flora types) and slash pine plantations (18 flora types), and had higher ratio of temperate flora. Natural secondary forests had more unique flora types in comparison with Masson pine plantations and slash pine plantations; (3) forest restoration approach had significant effects on forest community diversity. In tree, shrub and herb layer, natural secondary forest had higher species richness and Shannon-Wiener diversity index than Masson pine plantations and slash pine plantations. There was no significant difference in these indexes between slash pine plantations and Masson pine plantations; (4) multivariate analysis showed that these three reforestation approaches differed significantly in their species composition. Moreover, compared with slash pine plantations, the community composition of Masson pine plantations was more similar to the natural secondary forests. In conclusion, natural restoration is an important forest restoration approach since it was better than artificial plantations of P. massoniana and P. elliottii, yet the native species of P. massoniana plantations were superior to the introduced species of P. elliottii plantations in maintaining plant community structure.