蟲害侵?jǐn)_初期華山松群落草本層生態(tài)位特征和種間關(guān)系1)

胡文杰 潘磊 唐萬鵬 李歡歡 崔鴻俠 孫亮 宋云瑞

(湖北省林業(yè)科學(xué)研究院，武漢,430075)

Taking Pinus armandii community affected by insect infestation for 2 a as the research object, we investigated the herb layer of niche characteristics and interspecific relationship, the main species composition characteristics and interspecific interaction. The results showed that there were 35 families, 65 genera and 71 species of plants in the herb layer of Pinus armandii community in the early stage of pest infestation, among which Caryophyllaceae and Compositae were dominant. The niche width of the main species ranged from 1.66 to 2.31, among which the niche width of Parathelypteris nipponica, Astilbe chinensis and Galium hoffmeisteri were large, indicating that these species have a wide range of ecological adaptation. There was widespread niche overlap among species, and the overall mean of the niche overlap index was 0.32, which indicating that the herbaceous plants make full use of resources. The overall connectivity of the herbaceous layer was not significantly negative, indicating that the herbaceous layer was in an unstable state. The Pearson correlation test and Spearman rank correlation test showed that the number of species with significant connection accounted for more than 60% of the total species pairs, and the number of species pairs with negative connection was more than that with positive connection. It indicated that there was fierce competition among species, the relationship between species was not coordinated enough, and a stable coexistence relationship was not formed. With the advancement of pest infestation and the natural vegetation restoration, the species composition and interspecific relationship of the herb layer would further change.

草本層作為森林生態(tài)系統(tǒng)的重要組成部分，在很大程度上影響著生態(tài)系統(tǒng)的能量流動[1-2]。由于植物個體較小、生物量相對較低等原因，在森林群落的有關(guān)研究中草本層未得到足夠重視，但隨著人們逐漸認(rèn)識到林下植被層在生態(tài)學(xué)系統(tǒng)中的重要性，越來越多的研究開始聚焦到草本層。研究表明，草本層對林分更新幼苗的存活和生長、維持生物多樣性、動物生境等方面具有明顯影響[3-6]。同時，草本層植物生長會受到立地條件、林分結(jié)構(gòu)、凋落物厚度、土壤養(yǎng)分等多方面因素的影響[7-9]，其種間關(guān)系具有一定的復(fù)雜性。因此，定量研究草本層群落特征及種間相互關(guān)系具有重要的生態(tài)學(xué)意義[10]。

根據(jù)種間關(guān)系的定量描述分析特定群落物種間的相互影響方式已成為植物生態(tài)學(xué)研究的核心問題[11-12]。通過生態(tài)位特征研究可了解群落物種對資源利用的能力及種間功能關(guān)系，能夠充分表現(xiàn)不同物種在群落中的作用和地位[13]。種間聯(lián)結(jié)是對特定時空內(nèi)群落物種空間分布關(guān)系及功能關(guān)系的表達(dá)[14]，隨著群落正常演替，物種生態(tài)位逐步分化，群落結(jié)構(gòu)及物種組成逐漸趨于穩(wěn)定，各物種間則更傾向形成正聯(lián)結(jié)關(guān)系[15-16]。草本層植物對環(huán)境變化較為敏感[17]，開展草本層群落種間關(guān)系研究可較好地預(yù)測環(huán)境變化對森林群落的影響，同時可為基于種間關(guān)系的生物多樣性保護(hù)保育提供參考。……