CAJ | 학술논문

岷江冷杉(Abies faxoniana)是青藏高原东缘亚高山顶极森林植被的优势种之一,主要分布于岷江、大渡河和白龙江的上游地区.该文研究了岷江冷杉天然原始群落的种群结构和空间分布格局.样方大小为100 m ×60 m.测定了所有个体的坐标及其胸径、高度和冠幅.将岷江冷杉按大小级分为5级,即幼苗:H(高度)<0.33 m; 幼树: H≥0.33 m, 且 DBH(胸径)<2.5 cm; 小树: 2.5 cm≤DBH<7.5 cm; 中树: 7.5 cm≤DBH <22.5 cm和大树: DBH≥22.5 cm.采用了Morisita 指数 (Iδ)、方差均值比 (V/m), 聚块度指标(m*/m)和空间点格局分析方法 (SPPA) (采用了Ripley二次分析法)4种方法分析岷江冷杉的空间分布格局.结果表明: 1) 岷江冷杉种群结构稳定.因为其年龄结构表现为增长型, 幼苗幼树储备丰富,密度分别为2 217*hm-2和2 683*hm-2,可见岷江冷杉天然更新良好,进而通过其"移动镶嵌循环"更新维持其种群的稳定性.在大小级结构图中的一些缺刻和年龄结构图中的"断代"现象,是干扰的时空异质性在采样的时间和空间断面上的反映.2) 幼苗、幼树和小树在所有的研究尺度(从 1 m×1m 到 30 m×30 m)下都呈聚集分布.但中树和大树基本上呈随机分布.3) 聚集强度随尺度的变化而变化.上述的前3种方法表明,聚集强度随尺度的增加而减弱.但是,空间点格局分析法表明,岷江冷杉幼苗、幼树和小树的聚集强度首先随尺度的增加而增强,达到一定高峰后,随尺度的增加而减弱. 4) 岷江冷杉的空间分布格局是它与其自然环境长期作用的结果,同时也反映了其种群天然更新的格局和机制. 5) 4种分析方法对格局的判别基本一致, 但空间点格局分析法更能反映出格局强度随尺度的变化的关系,是值得推荐的一种分析空间分布格局的方法.使用空间点格局分析法的限制主要在于其计算和采样比较复杂.另外,由于Ripley 二次分析法对于"空白"的探测不敏感,需要进一步做一些方法上的改进. 岷江冷杉(Abies faxoniana)是青藏高原東緣亞高山頂極森林植被的優勢種之一,主要分佈于岷江、大渡河和白龍江的上遊地區.該文研究瞭岷江冷杉天然原始群落的種群結構和空間分佈格跼.樣方大小為100 m ×60 m.測定瞭所有箇體的坐標及其胸徑、高度和冠幅.將岷江冷杉按大小級分為5級,即幼苗:H(高度)<0.33 m; 幼樹: H≥0.33 m, 且 DBH(胸徑)<2.5 cm; 小樹: 2.5 cm≤DBH<7.5 cm; 中樹: 7.5 cm≤DBH <22.5 cm和大樹: DBH≥22.5 cm.採用瞭Morisita 指數 (Iδ)、方差均值比 (V/m), 聚塊度指標(m*/m)和空間點格跼分析方法 (SPPA) (採用瞭Ripley二次分析法)4種方法分析岷江冷杉的空間分佈格跼.結果錶明: 1) 岷江冷杉種群結構穩定.因為其年齡結構錶現為增長型, 幼苗幼樹儲備豐富,密度分彆為2 217*hm-2和2 683*hm-2,可見岷江冷杉天然更新良好,進而通過其"移動鑲嵌循環"更新維持其種群的穩定性.在大小級結構圖中的一些缺刻和年齡結構圖中的"斷代"現象,是榦擾的時空異質性在採樣的時間和空間斷麵上的反映.2) 幼苗、幼樹和小樹在所有的研究呎度(從 1 m×1m 到 30 m×30 m)下都呈聚集分佈.但中樹和大樹基本上呈隨機分佈.3) 聚集彊度隨呎度的變化而變化.上述的前3種方法錶明,聚集彊度隨呎度的增加而減弱.但是,空間點格跼分析法錶明,岷江冷杉幼苗、幼樹和小樹的聚集彊度首先隨呎度的增加而增彊,達到一定高峰後,隨呎度的增加而減弱. 4) 岷江冷杉的空間分佈格跼是它與其自然環境長期作用的結果,同時也反映瞭其種群天然更新的格跼和機製. 5) 4種分析方法對格跼的判彆基本一緻, 但空間點格跼分析法更能反映齣格跼彊度隨呎度的變化的關繫,是值得推薦的一種分析空間分佈格跼的方法.使用空間點格跼分析法的限製主要在于其計算和採樣比較複雜.另外,由于Ripley 二次分析法對于"空白"的探測不敏感,需要進一步做一些方法上的改進.
민강랭삼(Abies faxoniana)시청장고원동연아고산정겁삼림식피적우세충지일,주요분포우민강、대도하화백룡강적상유지구.해문연구료민강랭삼천연원시군락적충군결구화공간분포격국.양방대소위100 m ×60 m.측정료소유개체적좌표급기흉경、고도화관폭.장민강랭삼안대소급분위5급,즉유묘:H(고도)<0.33 m; 유수: H≥0.33 m, 차 DBH(흉경)<2.5 cm; 소수: 2.5 cm≤DBH<7.5 cm; 중수: 7.5 cm≤DBH <22.5 cm화대수: DBH≥22.5 cm.채용료Morisita 지수 (Iδ)、방차균치비 (V/m), 취괴도지표(m*/m)화공간점격국분석방법 (SPPA) (채용료Ripley이차분석법)4충방법분석민강랭삼적공간분포격국.결과표명: 1) 민강랭삼충군결구은정.인위기년령결구표현위증장형, 유묘유수저비봉부,밀도분별위2 217*hm-2화2 683*hm-2,가견민강랭삼천연경신량호,진이통과기"이동양감순배"경신유지기충군적은정성.재대소급결구도중적일사결각화년령결구도중적"단대"현상,시간우적시공이질성재채양적시간화공간단면상적반영.2) 유묘、유수화소수재소유적연구척도(종 1 m×1m 도 30 m×30 m)하도정취집분포.단중수화대수기본상정수궤분포.3) 취집강도수척도적변화이변화.상술적전3충방법표명,취집강도수척도적증가이감약.단시,공간점격국분석법표명,민강랭삼유묘、유수화소수적취집강도수선수척도적증가이증강,체도일정고봉후,수척도적증가이감약. 4) 민강랭삼적공간분포격국시타여기자연배경장기작용적결과,동시야반영료기충군천연경신적격국화궤제. 5) 4충분석방법대격국적판별기본일치, 단공간점격국분석법경능반영출격국강도수척도적변화적관계,시치득추천적일충분석공간분포격국적방법.사용공간점격국분석법적한제주요재우기계산화채양비교복잡.령외,유우Ripley 이차분석법대우"공백"적탐측불민감,수요진일보주일사방법상적개진.
Minjiang fir (Abies faxoniana) (MJF) is a dominant tree species of sub-alpine forests on the eastern edge of Qinghai-Tibetan Plateau, and is mainly distributed over the upper reaches of the Minjiang, Dadu and Bailong Rivers. The population structure and spatial pattern of MJF was studied in a naturally occurring stand. In a 100 m×60 m plot, the location of every tree was mapped, and the diameter at breast height (DBH), height and canopy area of each individual recorded. Trees were divided into five size classes: seedlings, height <0.33 m; saplings, height ≥ 0.33 m, and DBH<2.5 cm; small trees, 2.5 cm ≤ DBH<7.5 cm; medium Trees, 7.5 cm ≤ DBH <22.5 cm; and big trees, DBH ≥ 22.5 cm. The spatial pattern of MJF was analyzed using four independent methods: the Morisita index (Iδ), variance to mean ratio (V/m), the congregation index (m*/m) and the spatial point pattern analysis (SPPA) (Ripley's second-order- analysis method). The results revealed that MJF was a stable population with an inverse J_shaped size structure indicating good natural regeneration. Seedlings and saplings were very abundant, with densities of 2 217*hm-2 and 2 683*hm-2, respectively. Irregularities in the size structure histogram reflected past disturbances. The spatial analyses revealed that seedlings, saplings and small trees were clumped at most spatial scales studied which ranged from 1 m to 30 m, whereas the medium_sized trees and big trees were randomly distributed. The intensity of assemblage (IA) varied with scale. The first three methods indicated that IA decreased with increasing scale, but the SPPA method showed that the IA of seedlings, saplings and small trees first increased with increasing scale, and then declined at greater scales. We conclude that the spatial pattern of MJF in this subalpine forest resulted from long-term interactions between the MJF and its natural environment and mechanisms of natural regeneration that vary among species. The four different methods were very similar on the whole in their abilities to discriminate spatial patterns, but SPPA was superior in its ability to detect changes of IA with scale. Thus, we recommend SPPA for analyzing spatial patterns of populations. However, a limitation to using SPPA relates to the complexity of sampling and calculation requised and some refinements in Ripley's second-order-analysis are needed in order to better as it detect gaps.