帽兒山溪流中大型底棲動(dòng)物的定殖對(duì)兩種樹葉分解速率的影響1)

何凡　寇冀蒙　曾旖志　李婧　李勇　董雪　劉曼紅

(東北林業(yè)大學(xué)，哈爾濱，150040)

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帽兒山溪流中大型底棲動(dòng)物的定殖對(duì)兩種樹葉分解速率的影響1)

何凡寇冀蒙曾旖志李婧李勇董雪劉曼紅

(東北林業(yè)大學(xué)，哈爾濱，150040)

利用復(fù)合網(wǎng)袋法，對(duì)五角槭(Acermono)和稠李(Prunuspadus)兩種樹葉在帽兒山溪流中的分解速率進(jìn)行了為期105 d的研究。結(jié)果表明：五角槭和稠李樹葉在溪流中的分解速率常數(shù)(k)分別為0.024和0.030，符合指數(shù)衰減模型，均屬于快速分解組。定殖在五角槭和稠李樹葉上的大型底棲動(dòng)物種類分別有30種和26種，均以蜉蝣目小蜉屬(Ephemerellaspp.)為優(yōu)勢(shì)種。兩種樹葉上大型底棲動(dòng)物的攝食功能群的多度和生物量無顯著差異，而5次采樣間的差異顯著。定殖在五角槭樹葉上的直接集食者比例最高(45.9%)，其次是捕食者(23.8%)和撕食者(22.4%)，最少的為過濾收集者，僅占4.6%；定殖在稠李樹葉上直接集食者的比例最高(44.6%)，其次是捕食者(26.1%)和撕食者(25.4%)，過濾收集者僅占1.8%。說明在帽兒山溪流中，隨著溪流增大，撕食者種類減少，直接集食者類群的密度對(duì)樹葉分解速率具有顯著影響。

五角槭；稠李；分解速率；大型底棲動(dòng)物；功能攝食群

By composite mesh bag method, we studied the leaves decomposition process ofAcermonoandPrunuspadusfor 105 days in the streams of Maoer Mountain. The leaves decomposition rates (k) ofA.monoandP.paduswere 0.024 and 0.03, respectively, according with the declined exponential equation, belonging to the fast decomposition groups. The species numbers colonization benthic macro-invertebrate of theA.mono(30) leaf was higher than that ofP.padus(26) leaves, both with Ephemeroptera (Ephemerellaspp.) as dominant species. There were no significant differences between two species of the feeding function group of the benthic macro-invertebrate, but the difference was significant between 5 samplings. Between the colonized macro-invertebrate functional feeding groups, the direct gatherer inA.monowas dominant (45.9%), followed by the predator (23.8%), the shredder (22.4%), and the filter collector (4.6%). The direct gatherer inP.paduswas dominant (44.6%), followed by the predator (26.1%), the shredder (25.4%), and the filter collector (1.8%). In the stream of Maoer Mountain, with the increase of the stream, the shredder species decreased, and the direct gatherer group density had a significant effect on the leaf decomposition rate.

樹葉凋落物的分解是溪流生態(tài)系統(tǒng)營(yíng)養(yǎng)物質(zhì)循環(huán)與能量流動(dòng)的重要環(huán)節(jié)，異源有機(jī)物作為源頭溪流中大型底棲動(dòng)物的主要食物來源，其輸入對(duì)于保持溪流中生物群落的完整性發(fā)揮著重要的作用[1-3]，分解過程主要分為3個(gè)階段，即首先是在雨水的淋溶作用下導(dǎo)致樹葉中的可溶性有機(jī)物及無機(jī)礦物質(zhì)迅速流失的過程，隨后微生物的附著、生長(zhǎng)與繁殖活動(dòng)使樹葉內(nèi)部結(jié)構(gòu)發(fā)生改變而緩慢降解，以及由溪流里生存的大型底棲動(dòng)物的定殖和取食活動(dòng)造成樹葉的機(jī)械破碎。……