林窗大小对马尾松人工林土壤动物群落的影响

发布时间：2018-04-28 08:12

本文选题：马尾松人工林 + 林窗　；参考：《四川农业大学》2016年硕士论文

【摘要】：土壤动物作为土壤生态系统中重要的组成部分,其群落组成和功能对土壤形成、物质循环和能量流动具有重大意义。马尾松(Pinus massoniana)是长江中上游地区主要的造林树种,由于其耐干旱瘠薄,适应能力强,在该区域人工林构成中占有很大比例,但结构单一的马尾松人工林存在生产力不高、生物多样性低、地力衰退、病虫害频发等生态问题,严重制约其生态、经济和社会效益。通过人为砍伐形成林窗,对马尾松人工林进行改造是有效提升生态服务功能和实现人工林可持续经营的重要途径。本研究调查了长江上游地区马尾松人工林7种不同大小林窗内(G1：100 m~2、G2：225m~2、G3：400 m~2、G4：625 m~2、G5：900 m~2、G6：1225 m~2、G7：1600 m~2)土壤动物群落的区系组成、分布特征、多样性和相似性特征以及功能类群等。大型土壤动物采用手拣法,中小型干生、湿生土壤动物分别采用Tullgren干漏斗和Baermann湿漏斗分离。结果表明：(1)2015年1月、4月、7月、10月共捕获土壤动物33859只,隶属于6门14纲35目265类(附表1),其中,7种不同大小林窗中捕获土壤动物29502只,林下对照捕获土壤动物4357只。优势类群为线虫纲,占捕获总数的81.07%；常见类群包括线蚓科、懒甲螨群、等节跳科和若甲螨群4个类群,占捕获总数的10.77%；稀有类群主要包括绥螨科、奥甲螨群、双翅目(幼)和蚁科等260个类群,占捕获总数的8.16%。(2)马尾松人工林林窗土壤动物的平均密度表现为随着林窗面积的增大而降低,在G5(900m~2)林窗土壤动物的平均密度显著提高且达到最大,随后在G5-G7(900-1600m~2)林窗间再次表现出随林窗面积增大而降低的规律；土壤动物的类群数表现为随着林窗面积的增大而上升,在G5(900 m~2)林窗达到最大,随后随着林窗面积的增大,类群数逐步减少；土壤动物的平均密度排序为G5(6.41×105)G6(3.87×105)G1(1.77×105)G7(1.76×105)G2(1.69×105)G3(1.49×105)CK(1.21×105)G4(0.90×105),类群数排序为G5(157)G2(138)G4(136)G3(135)G7(131)G6(130)G1(127)CK(121)；各林窗土壤动物的平均密度总体表现为10月最高,1月最低,4月或7月次之,类群数总体表现为4月最多,1月最少,7月或10月次之的分布规律。(3)马尾松人工林林窗内大型土壤动物的平均密度和类群数均表现出随着林窗面积增大而逐步增高,在G4-G5(625-900m~2)林窗达到最大,随后随着林窗面积增大逐步减少；中小型土壤动物的平均密度总体表现为大型林窗高于中小型林窗,最大值出现在G5-G6(900-1225m~2)林窗；中小型土壤动物的类群数总体表现出与大型土壤动物相似的分布规律,但最大值出现在G4-G6(625-1225 m~2)林窗。(4)马尾松人工林各林窗土壤动物群落垂直分布表聚性明显,除1月部分林窗出现枯落物层类群数低于0-5 cm层的逆向分布现象外,其余林窗各季节从枯落物层依次往下,随深度增加,土壤动物的类群数均逐渐减小,但各季节各林窗枯落物层土壤动物的平均密度均低于0-5 cm层。(5)马尾松人工林不同大小林窗内,杂食性土壤动物密度所占的比例最高,均占捕获总密度的60%以上,其次依次为腐食性植食性菌食性捕食性枯食性粪食性,其中大型林窗内杂食性土壤动物的密度明显高于中小型林窗。各林窗内土壤动物类群以腐食性、捕食性、杂食性和植食性为主,其中腐食性土壤动物类群数所占的比例最高,均占各林窗捕获总类群数的30%以上；各林窗腐食性和捕食性土壤动物表现出随着林窗面积增大,类群数所占比例逐步降低的趋势。随着时间推移,各林窗内杂食性土壤动物密度所占比例有所提高,而其他食性土壤动物的变化均不显著。(6)林窗的形成降低了小型和大型林窗内土壤动物的多样性指数和均匀度指数,但对中型林窗土壤动物的多样性指数和均匀度指数影响较小。马尾松人工林不同大小林窗内土壤动物的多样性指数和均匀度指数分布规律基本一致,在G1-G4(100-625m~2)间均表现出随林窗面积增大土壤动物的多样性和均匀度增大,在G4(625 m~2)林窗达到最大,在G5(900m~2)林窗显著降低,随后G5-G7(900-1600m~2)间再次表现为随林窗面积的增大而增大的规律,优势度指数的变化规律则与二者相反；土壤动物的丰富度指数表现相对平稳,总体呈现出林窗面积越大其土壤动物丰富度指数越高的特征。(7)研究发现,林窗面积对土壤动物的群落结构和多样性特征(除香农多样性指数外)影响极显著(P0.01),而季节变化与林窗面积的交互作用除对土壤动物的类群数和丰富度指数作用不显著外(P0.05),其余均造成极显著影响(P0.01)。相关性分析显示：林窗面积与土壤动物的群落组成和密度—类群指数表现出极显著正相关性(P0.01),与优势度指数、丰富度指数存在显著正相关性(P0.05),而与均匀度指数存在极显著负相关关系(P0.01),与多样性指数存在显著负相关关系(P0.05)。本研究表明,在马尾松人工林抚育初期,中等大小的林窗面积(625-900m~2)内土壤动物的类群和个体丰富度最高且显著高于林下,故在马尾松人工林的改造和管理过程中可以通过营造中型林窗来增加土壤动物的丰富度,从而维持马尾松人工林地下生态系统的多样性和稳定性。
[Abstract]:Soil animal is an important component of soil ecosystem, and its community composition and function are of great significance to soil formation, material circulation and energy flow. Pinus massoniana is the main afforestation tree in the middle and upper reaches of the Yangtze River. Because of its drought tolerance and adaptability, it is occupied in the area of artificial forest in this region. There is a large proportion, but there are many ecological problems, such as low productivity, low biological diversity, depression, frequent pests and other ecological problems, which seriously restrict the ecological, economic and social benefits. By artificially cutting down the forest window, the modification of the Pinus massoniana plantation is an effective improvement of the ecological service function and the realization of artificial forest. This study investigated the floristic composition, distribution, diversity, similarity and functional groups of the 7 different size forest windows (G1:100 m~2, G2:225m~2, G3:400 m~2, G4:625 m~2, G5:900 m~2, G6:1225 m~2, G7:1600) in the Pinus massoniana Plantation in the upper reaches of the Yangtze River. The soil animals were separated by the Tullgren dry funnel and the Baermann wet funnel respectively. The results showed that: (1) 33859 soil animals were captured in January 2015, April, July, and October, belonging to 6 doors, 14 classes, 35 orders, 265 categories (Table 1), of which 29502 of the soil animals were captured in 7 different sizes of forest windows and under forest. The dominant groups of 4357 soil animals are nematodes. The dominant group is nematode, accounting for 81.07% of the total. The common groups include the line vermis, the lazari mite group, the same group of 4 groups, accounting for 10.77% of the total number of the total. The rare groups mainly include the suiveridide, the methoclite group, the Diptera (young) and the formicide, which account for 8.16% of the total number of captures. (2) the average density of soil animals in the forest window of Pinus massoniana Plantation decreased with the increase of the area of the forest window. The average density of the soil animals in the G5 (900m~2) forest window increased significantly and reached the maximum, and then the law of decreasing with the increase of forest window surface accumulated between the windows of the G5-G7 (900-1600m~2) forest; the group number of soil animals showed. As the area of the forest window increased, the maximum of the G5 (900 m~2) forest window was reached, and the number of groups gradually decreased with the increase of the area of the forest window. The average density of the soil animals was G5 (6.41 * 105) G6 (3.87 * 105) G1 (1.77 * 105) G7 (1.76 x 105) G2 (1.69 * 105) G3 (1.49 * 105) CK (1.49 * 105) G4 (1.69 * 105), and the group number was sorted as G5 G2. (138) G4 (136) G3 (135) G7 (131) G6 (130) G1 (127) CK (121); the average density of soil animals in each forest window was the highest in October, the lowest in January, the lowest in April or July, and the population in April was the most in April, at least in January and January. (3) the average density and group number of large soil animals in the Pinus massoniana Plantation window. The average density of the G4-G5 (625-900m~2) forest window increased gradually with the increase of the area of the forest window, and gradually decreased with the increase of the area of the forest window. The average density of the small and medium soil animals showed that the large forest window was higher than the medium and small forest windows, the maximum value appeared in the G5-G6 (900-1225m~2) forest window, and the number of the small and medium soil animals. The distribution pattern was similar to that of large soil animals, but the maximum value appeared in the G4-G6 (625-1225 m~2) window. (4) the vertical distribution of the vertical distribution of the soil animal community in the forest windows of Pinus massoniana plantation was obvious. In addition to the reverse distribution of the litter layer of the litter layer in the January part of the forest window, the rest of the other forest windows were from the dry and falling seasons. The number of soil animals decreased gradually with the increase of depth, but the average density of soil animals in the litter layer in each season was lower than 0-5 cm layer. (5) the proportion of the omnivorous soil animal density was the highest in the different size forest windows of Pinus massoniana plantation, which accounted for more than 60% of the total capture density, followed by decay in turn. Predatory, predatory, predatory, predatory, predatory fecal food, of which the density of omnivorous soil animals in large forest windows is significantly higher than that of small and medium-sized forest windows. The soil animal groups in the windows are mainly humorous, predatory, omnivorous and phytophagous, among which the proportion of the species of humic soil animals is the highest, which accounts for the total species of the forest windows. More than 30% of the number of herd and predatory soil animals showed a gradual decrease in the proportion of group numbers as the area of the forest window increased. As time went on, the proportion of the animal density in the omnivorous soil in each window increased, but the changes of other food soil animals were not significant. (6) the formation of the forest window decreased. The diversity index and evenness index of soil animals in small and large forest windows have little influence on the diversity index and evenness index of soil animals in medium window. The distribution of diversity index and evenness index of soil animals in different sizes of Pinus massoniana plantation is basically the same, and it is shown between G1-G4 (100-625m~2). With the increase of forest area, the diversity and evenness of soil animals increased, the window of G4 (625 m~2) reached the maximum, the window of G5 (900m~2) decreased significantly, and then G5-G7 (900-1600m~2) increased again with the increase of the area of the forest window. The variation rule of the dominance index was opposite to the two, and the richness index of soil animal was the index table. The larger the forest window area is, the higher the soil animal richness index is. (7) the study found that the forest window area has a very significant influence on the community structure and diversity of soil animals (except the Shannon diversity index) (P0.01), but the interaction of seasonal variation and forest window area is not only the group number of soil animals. And the effect of the richness index was not significant (P0.05), and the rest had very significant influence (P0.01). The correlation analysis showed that the area of forest window had a very significant positive correlation with the community composition and density index of soil animals (P0.01), and there was a significant positive correlation (P0.05) with the dominance index and the richness index (P0.05), but with the evenness index. There was a very significant negative correlation (P0.01) and a significant negative correlation with the diversity index (P0.05). This study showed that in the early tending of Pinus massoniana plantation, the abundance of soil animals in the middle size of the forest window area (625-900m~2) was the highest and significantly higher than that in the undergrowth. Therefore, the transformation and management of the Pinus massoniana Plantation In order to maintain the diversity and stability of the underground ecosystem of Masson pine plantations, it is possible to increase soil animal richness by creating medium-sized forest windows.

【学位授予单位】：四川农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S714

【参考文献】