趙鳴飛,邢開(kāi)雄,王宇航,王國(guó)義,薛 峰,左婉怡,康慕誼,*

1 北京師范大學(xué)地表過(guò)程與資源生態(tài)國(guó)家重點(diǎn)實(shí)驗(yàn)室, 北京 100875 2 北京師范大學(xué)資源學(xué)院, 北京 100875

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蘆芽山寒溫性針葉林冠層下植被beta多樣性格局及其成因

趙鳴飛1,2,邢開(kāi)雄1,2,王宇航1,2,王國(guó)義1,2,薛 峰1,2,左婉怡1,2,康慕誼1,2,*

1 北京師范大學(xué)地表過(guò)程與資源生態(tài)國(guó)家重點(diǎn)實(shí)驗(yàn)室, 北京 100875 2 北京師范大學(xué)資源學(xué)院, 北京 100875

群落構(gòu)建機(jī)制是生態(tài)學(xué)的中心議題之一。對(duì)山地植被beta多樣性格局及其成因的探究有助于加深對(duì)此問(wèn)題的認(rèn)識(shí)。以蘆芽山寒溫性針葉林群落冠層下植被為研究對(duì)象,結(jié)合野外調(diào)查與室內(nèi)實(shí)驗(yàn)獲取的詳細(xì)數(shù)據(jù),運(yùn)用Mantel檢驗(yàn)、普通最小二乘回歸和典范對(duì)應(yīng)分析(CCA)等統(tǒng)計(jì)方法,探討了林下植被的beta多樣性格局及其成因,結(jié)果顯示：(1)沿海拔梯度相鄰群落間草本層物種周轉(zhuǎn)率呈現(xiàn)遞減格局,而灌木層變化規(guī)律不明顯；(2)灌、草層beta多樣性與海拔差異、地理距離呈顯著正相關(guān)關(guān)系,而與局地環(huán)境異質(zhì)性關(guān)系不顯著?？刂坪０巫饔煤蟀l(fā)現(xiàn),灌、草層beta多樣性與地理距離關(guān)系依然顯著,而當(dāng)消除地理距離的線性影響后,beta多樣性與海拔關(guān)系也變得不顯著(3) CCA模型中,環(huán)境因子共解釋了物種組成變異的74.4%,其中,海拔、坡度、凋落物厚度、喬木密度與總干面積對(duì)林下灌、草植被物種組成具有顯著影響,但土壤因子的作用未見(jiàn)顯著。綜上,生境篩濾與擴(kuò)散限制共同主導(dǎo)了蘆芽山寒溫性針葉林冠層下群落構(gòu)建過(guò)程,但擴(kuò)散限制的影響強(qiáng)于生境篩濾作用。

海拔梯度；物種周轉(zhuǎn)率；群落構(gòu)建；擴(kuò)散限制；生境篩濾

理解并闡釋群落構(gòu)建機(jī)制一直是生態(tài)學(xué)的核心問(wèn)題之一[1- 3]。在當(dāng)前由人類(lèi)活動(dòng)所主導(dǎo)的全球氣候變化、生物第六次大滅絕背景下,對(duì)該問(wèn)題的研究顯得尤為緊迫[4-5]。探索群落間物種多樣性的空間變化格局,也即beta多樣性的成因,是解決該問(wèn)題的關(guān)鍵所在?！吧鷳B(tài)位理論”和“群落中性理論”已成為解釋物種共存機(jī)制的兩種主流觀點(diǎn)。前者認(rèn)為“生境篩濾(environmental filtering)”以及種間相互作用等確定性因素決定群落的構(gòu)建[2],而后者則強(qiáng)調(diào)與隨機(jī)因素有關(guān)的空間過(guò)程,“擴(kuò)散限制(dispersal limitation)”同樣能夠刻畫(huà)群落物種組成與時(shí)空動(dòng)態(tài)[6]。目前,學(xué)界傾向于將二者整合起來(lái),共同對(duì)beta多樣性成因給予定量解釋[7- 10]。然而,環(huán)境因子自身往往具有地理結(jié)構(gòu)[11],這種天然的空間自相關(guān)屬性使得分離上述兩類(lèi)作用存在困難[8,10, 2]。因此,在不同的研究尺度下區(qū)分二者的“作用力”大小已成為當(dāng)今生態(tài)學(xué)界的研究熱點(diǎn)[8-9,13]。

山地系統(tǒng)在相對(duì)有限的空間內(nèi)通常具有寬廣的水熱梯度和較大的生境異質(zhì)性[14-15]。海拔梯度能夠表征溫度、濕度、光照和土壤等諸多生境要素。例如,垂直方向上的氣溫變率約比在緯向上快一千倍[16]。因此,山地是探索物種形成、群落建構(gòu)以及多樣性漸變等關(guān)鍵機(jī)制的理想之地[14,17]?？傮w而言,以往有關(guān)山地多樣性的經(jīng)驗(yàn)研究更多聚焦于物種豐富度格局[18],而對(duì)于山地beta多樣性格局及其形成機(jī)制的探討相對(duì)不足[10,17-18]。

山西蘆芽山具有較大相對(duì)垂直高差,并保存有大面積完好典型的寒溫性針葉林,這些森林屬于演替后期相對(duì)穩(wěn)定的頂級(jí)群落,其建群種組成簡(jiǎn)單,因此為冠層下物種創(chuàng)造了同質(zhì)性較高的生境條件[19]。本文以蘆芽山針葉林群落林冠下各層植物的beta多樣性為研究對(duì)象,基于詳細(xì)的野外調(diào)查和室內(nèi)實(shí)驗(yàn)數(shù)據(jù),嘗試回答以下科學(xué)問(wèn)題：(1)冠層下物種beta多樣性所呈現(xiàn)的海拔周轉(zhuǎn)格局；(2)海拔差異、地理距離以及局地生境異質(zhì)性差異對(duì)beta多樣性的影響；(3)物種組成與環(huán)境因子的定量關(guān)系。

1 材料與方法

1.1 研究區(qū)概況

研究區(qū)位于山西省西北部呂梁山脈北端蘆芽山(38°36′—39°02′N(xiāo), 111°46′—112°54′E),其主峰荷葉坪海拔2783 m。該地域?qū)倥瘻貛О霛駶?rùn)區(qū),氣候的大陸性特征顯著,夏季涼爽多雨,冬季寒冷干燥。年平均氣溫5—8℃,1月平均氣溫-12—-8℃,7月平溫20—25℃,無(wú)霜期130—170 d；年降水量350—500 mm,主要集中于6—8月。蘆芽山植被具有明顯的垂直地帶性,低中山以暖溫帶落葉闊葉林和灌草叢為主；海拔1750—2600 m一帶覆蓋著茂密的寒溫性針葉林,其建群種由青杄(Piceawilsonii)、白杄(Piceameyeri)和華北落葉松(Larixprincipis-rupprechtii)組成；2450 m以上開(kāi)始出現(xiàn)亞高山灌叢草甸,直至峰頂[20]。對(duì)應(yīng)植被帶變化,土壤亦呈垂直地帶性分布,從低海拔起依次為：山地褐土、山地淋溶褐土、棕色森林土和亞高山草甸土[19]。

1.2 樣地設(shè)置及取樣方法

野外樣地布設(shè)于海拔1800—2650 m的典型針葉林帶,從下至上,海拔每升高50 m設(shè)置20 m×30 m樣地一個(gè)(進(jìn)一步劃分為6個(gè)10 m×10 m樣格),共計(jì)17個(gè)。對(duì)樣方內(nèi)胸徑大于3 cm的喬木進(jìn)行每木調(diào)查,記錄其樹(shù)名、胸徑、高度和枝下高等特征。選擇兩個(gè)對(duì)角位置的10 m×10 m樣格作為灌木樣方,調(diào)查其內(nèi)灌木種類(lèi)、高度和蓋度(注：最高處兩個(gè)樣地未發(fā)現(xiàn)灌木種)。于每樣格中間位置設(shè)置1 m×1 m草本樣方(共6個(gè)),統(tǒng)計(jì)其種類(lèi)、蓋度與高度。同時(shí)利用GPS記錄樣地經(jīng)緯度、海拔高度,并利用羅盤(pán)記錄其坡度、坡向等信息。分析時(shí)依余弦公式[21]將坡向轉(zhuǎn)換為0—1之間的數(shù)據(jù),以反映生境的干濕程度。在進(jìn)行植被調(diào)查的同時(shí),于每一樣格隨機(jī)選取3個(gè)點(diǎn)(共18個(gè)重復(fù)),使用鋼尺測(cè)量凋落物厚度。利用環(huán)刀收集0—20 cm層土壤樣品,帶回實(shí)驗(yàn)室經(jīng)風(fēng)干、研磨過(guò)篩后,分別采用“濕燃燒法”、“凱氏定氮法”和“鉬銻抗比色法”測(cè)定土壤有機(jī)碳、全氮與全磷含量。調(diào)查記錄到維管植物166種,其中喬木15種、灌木24種、草本127種。

1.3 統(tǒng)計(jì)分析1.3.1 物種周轉(zhuǎn)率與環(huán)境距離

本研究利用物種“有-無(wú)”的二元數(shù)據(jù),通過(guò)計(jì)算樣地間Simpson相異性指數(shù)(beta-sim) 來(lái)度量物種周轉(zhuǎn)率[22],也即beta多樣性。其計(jì)算公式如下：

beta-sim=min(b,c)/[a+ min(b,c)]

式中,a為兩樣地共有種,b和c分別為兩樣地獨(dú)有種。該指數(shù)在樣地物種數(shù)不均衡的情況下仍舊表現(xiàn)穩(wěn)健,因而被廣泛應(yīng)用于生態(tài)學(xué)以及生物地理學(xué)領(lǐng)域[22-23]?；跇拥亻g海拔差異計(jì)算得到“海拔距離矩陣”；基于經(jīng)緯度數(shù)據(jù)計(jì)算得到樣地之間水平“地理距離矩陣”；類(lèi)似的,以坡度、坡向、土壤深度、土壤元素、凋落物厚度、平均冠層高(平均樹(shù)高與平均枝下高之差)、總干面積(由胸徑計(jì)算得到)和立木密度等10個(gè)指標(biāo)作為環(huán)境異質(zhì)性因子,經(jīng)標(biāo)準(zhǔn)化消除量綱影響后,按歐氏距離綜合計(jì)算獲得樣地間“環(huán)境距離矩陣”。

為探究灌草群落沿海拔方向的物種周轉(zhuǎn)率格局,筆者計(jì)算了空間上相鄰樣地之間的beta-sim指數(shù),并進(jìn)一步通過(guò)Kruskal-Wallis秩和檢驗(yàn)來(lái)比較灌、草層之間beta多樣性大小。

1.3.2 回歸分析與Mantel檢驗(yàn)

首先使用普通最小二乘回歸分別考察灌木層和草本層beta多樣性與海拔差異、地理距離及環(huán)境距離之間的相互關(guān)系。由于點(diǎn)對(duì)數(shù)據(jù)之間并不獨(dú)立,使用基于置換檢驗(yàn)的Mantel-test作為補(bǔ)充,并利用Partial Mantel-test來(lái)分析各距離矩陣對(duì)beta多樣性的獨(dú)立影響(9999次置換)。相關(guān)性由標(biāo)準(zhǔn)化Mantel系數(shù)(基于Pearson相關(guān)系數(shù))度量[24]。

1.3.3 排序

利用典范對(duì)應(yīng)分析(Canonical Correspondence Analysis, CCA)綜合分析了冠層群落物種組成與環(huán)境因子的關(guān)系。參與計(jì)算的植物種僅包括樣方內(nèi)詳細(xì)記錄有屬性數(shù)據(jù)的95個(gè)物種。排序之前,首先依據(jù)“膨脹因子”來(lái)評(píng)估自變量之間可能存在的“多重共線性”。經(jīng)計(jì)算,所有變量的“膨脹因子”均小于10,也即該問(wèn)題不會(huì)顯著影響分析結(jié)果。定量物種數(shù)據(jù)矩陣由重要值組成,本文對(duì)各灌、草植物種重要值采用統(tǒng)一計(jì)算公式如下：

重要值=(相對(duì)高度+相對(duì)蓋度)/2

以上統(tǒng)計(jì)分析由R軟件完成,并涉及vegan軟件包。

2 結(jié)果

2.1 Beta多樣性沿海拔方向上的分布格局

隨著海拔的升高,灌木層物種的beta-sim并無(wú)明顯趨勢(shì)(圖1)；而草本層物種則呈現(xiàn)顯著的遞減格局。平均來(lái)看,相鄰樣地間灌木beta-sim多樣性指數(shù)為0.393±0.152,草本為0.358±0.103,二者之間周轉(zhuǎn)率相當(dāng),并無(wú)顯著差異(KW-test,P=0.287)。

圖1 相鄰樣地灌木層和草本層beta多樣性沿海拔梯度的分布格局Fig.1 Beta-sim variation between paired-adjacent sampling sites along the elevational gradient for shrubs and herbs圖中曲線為L(zhǎng)oess擬合趨勢(shì)線(span=0.75)

2.2 Beta多樣性與海拔差異、水平距離及環(huán)境距離的相關(guān)性

總體而言,冠層下植被兩兩樣地間beta多樣性均隨海拔差異、地理距離的增大而具有增加趨勢(shì)(圖2,P<0.001),地理距離對(duì)冠層下植被beta變異的線性解釋率尤為突出。具體來(lái)說(shuō),海拔差異對(duì)灌木的解釋率為0.265(調(diào)整后決定系數(shù)R2-adj,下同),草本為0.623；而地理距離則分別達(dá)0.342和0.758。而群落局地生境異質(zhì)性差異與灌、草的beta雖然也呈正相關(guān)趨勢(shì),但并不顯著(圖2,P>0.05)。

Mantel檢驗(yàn)與回歸分析結(jié)果相一致(表1),灌、草beta多樣性均與海拔變化、地理距離以及環(huán)境距離呈正相關(guān)關(guān)系,前二者同樣達(dá)極顯著水平(P<0.001),而與環(huán)境距離則并不顯著(P=0.071)。然而,當(dāng)通過(guò)Partial-Mantel檢驗(yàn)控制水平距離影響僅考慮海拔的凈效應(yīng)時(shí),其關(guān)系也變得不顯著；相反情況,水平距離與灌、草beta多樣性則依然呈顯著正相關(guān)(表1,P<0.001)。

圖2 Beta多樣性與海拔差異、地理距離、環(huán)境距離之間的關(guān)系Fig.2 Scatter plots of species dissimilarity against elevational distance, geographical distance and environmental distance圖中直線為線性回歸擬合線(虛線表示關(guān)系不顯著)

2.3 群落物種組成與環(huán)境因子的關(guān)系

CCA模型全局F檢驗(yàn)達(dá)到顯著水平(F-pseudo=1.320,P=0.004,9999次置換),共解釋灌、草層物種組成變異的74.4%(總慣量為3.695)。前兩軸(特征值分別為0.609和0.251)累積解釋總變異的23.3%。環(huán)境因子中的海拔、凋落物厚度、坡度、喬木密度與總干面積對(duì)林下灌、草植被構(gòu)成具有顯著影響(圖3,表2),而土壤因子的作用卻均不顯著。排序第一軸主要代表了海拔(相關(guān)系數(shù)：0.998,下同)、總干面積(0.892)和坡度(-0.996)；第二軸主要同喬木密度(0.843)和凋落物厚度(-0.970)有關(guān)。

3 討論

物種周轉(zhuǎn)率描述了群落沿生境梯度上的物種替代速率[25]。隨著海拔的升高,相鄰群落草本層beta呈現(xiàn)

表1 Beta多樣性與海拔差異、地理距離及環(huán)境距離之間的相關(guān)性

表2 環(huán)境因子與CCA前兩排序軸的關(guān)系

環(huán)境因子與排序軸之間相關(guān)關(guān)系的顯著性基于9999次置換檢驗(yàn)

圖3 針葉林群落冠層下植被與環(huán)境因子關(guān)系的CCA排序圖Fig.3 CCA triplot of the understory of boreal coniferous communities related to environmental covariates

單調(diào)遞減格局(圖1),這與多數(shù)經(jīng)驗(yàn)案例相符合[26- 28]。一方面低海拔地區(qū)有著相對(duì)良好的水熱條件,可容納更多物種共存；另一方面,低海拔地區(qū)易受到更大強(qiáng)度的人為干擾,生境異質(zhì)性更高,從而導(dǎo)致beta多樣性增加。當(dāng)然,遞減格局也可以由“Rapoport”法則解釋,能夠分布在高海拔地區(qū)的物種其生態(tài)幅較為寬廣,因此相鄰海拔段的群落物種組成趨同,進(jìn)而beta多樣性降低[29]。

生態(tài)位理論認(rèn)為,生境差異主導(dǎo)了beta多樣性格局[30]。而中性理論主張,群落建構(gòu)主要取決于物種的擴(kuò)散能力,所以,空間距離可以看做beta多樣性的關(guān)鍵成因[31]。本研究結(jié)果顯示,灌木、草本層的beta多樣性均與水平方向上的地理距離、垂直方向上的海拔差異極顯著相關(guān)。然而,海拔本身代表空間的一個(gè)維度,同時(shí)又與環(huán)境因子之間存在很強(qiáng)的協(xié)變關(guān)系,特別是與溫度,二者之間幾乎完全共線。因此,海拔距離本身雖然對(duì)beta多樣性存在較高解釋量(圖2),但卻難以厘清生態(tài)位過(guò)程或中性過(guò)程的相對(duì)貢獻(xiàn)。而上述問(wèn)題對(duì)于群落之間的水平地理距離并不明顯。通過(guò)偏Mantel檢驗(yàn)排除海拔的線性影響后,地理距離對(duì)beta的“純作用”依然顯著(表1)。這意味著山地系統(tǒng)自身的特殊性可能對(duì)空間作用具有“放大效應(yīng)”。

一方面,從宏生態(tài)觀點(diǎn)來(lái)看,山地系統(tǒng)作為可見(jiàn)天然屏障對(duì)物種長(zhǎng)距離擴(kuò)散起著十分顯著的阻隔作用[32]。即便對(duì)于山地生態(tài)系統(tǒng)內(nèi)部而言,由于地形崎嶇復(fù)雜,使其較之其他相對(duì)連通的地理單元(如平原、河岸帶等)對(duì)繁殖體短距離遷移阻力要大得多。擴(kuò)散受阻意味著不同斑塊內(nèi)種群之間的基因流強(qiáng)度減弱,加之復(fù)雜地形增加了生境異質(zhì)性,有利于提高物種形成速率。因此,山地系統(tǒng)特有種豐富[33-34],加之局地斑塊孤立性較高進(jìn)而提高了群落間的beta多樣性。另一方面,生態(tài)位過(guò)程與擴(kuò)散限制對(duì)群落間beta多樣性影響力大小具有尺度依賴(lài)特性[35]。研究尺度越小,生態(tài)漂變、空間自相關(guān)等中性過(guò)程的作用將被凸顯；而隨著尺度增大,環(huán)境梯度作用才逐漸凸顯出來(lái)[35-36]。在本研究中,樣地間最遠(yuǎn)距離僅為10km,屬于小尺度案例[37],這有利于觀測(cè)到空間因子對(duì)物種聚集的影響。另外,還發(fā)現(xiàn),以土壤、地形和生物因子為代表的局地生境異質(zhì)性與beta多樣性之間并無(wú)顯著關(guān)系。這可能由于蘆芽山寒溫性針葉林多處于演替后期,喬木層物種組成相對(duì)單一,從而創(chuàng)造了一致性程度較高的林下生境,因此,對(duì)物種的篩選作用趨同。綜上,可以認(rèn)為,擴(kuò)散限制可能是蘆芽山冠層下植被beta多樣性形成的主要機(jī)制。

然而,局地尺度生境異質(zhì)性與beta多樣性變異關(guān)系不顯著并非意味其對(duì)群落物種組成沒(méi)有貢獻(xiàn)。由CCA分析可以看出,除海拔(間接代表了水熱梯度)外,來(lái)自林冠層優(yōu)勢(shì)種(喬木層密度,總干面積,凋落物厚度)以及地形因子(坡度)的影響與灌、草層植被均有顯著的定量關(guān)系(圖3,表2)。由此表明,局地異質(zhì)性因子對(duì)該區(qū)下層植被結(jié)構(gòu)、物種組成以及alpha多樣性同樣具有重要影響。特別是來(lái)自林冠的調(diào)節(jié)作用,其結(jié)構(gòu)能夠改變冠層下的光照條件[38],同時(shí)作為地表凋落物的主要來(lái)源也會(huì)間接影響到下層物種多樣性[39]。例如,林下環(huán)境生長(zhǎng)的木本植物對(duì)光線需求一般高于草本植物。通過(guò)調(diào)查發(fā)現(xiàn),蘆芽山云杉林具有非常高的郁閉度,導(dǎo)致灌木層物種普遍受到光資源脅迫,進(jìn)而增加了物種組成的不確定性(樣地灌木物種豐富度變異系數(shù)為37.4%,高于草本的28.1%)。這在一定程度上解釋了本文所涉及的統(tǒng)計(jì)分析中,灌木模型的殘差為何均高于草本。

4 結(jié)論

本研究揭示了蘆芽山寒溫性針葉林群落冠層下植被的beta多樣性沿海拔、空間以及環(huán)境梯度的變化格局,發(fā)現(xiàn)以擴(kuò)散限制為代表的中性過(guò)程可能比生境篩濾等生態(tài)位過(guò)程對(duì)研究區(qū)的群落構(gòu)建更為重要。同時(shí)作為補(bǔ)充,CCA模型展示了局地生境異質(zhì)性因子對(duì)冠下層物種組成的顯著影響?；趯?duì)beta多樣性變異來(lái)源的剖析,有助于加深人們對(duì)于群落物種集聚過(guò)程的理解,這對(duì)于全球氣候變化背景下的生物多樣性保育與維持具有非常重要的理論意義和應(yīng)用價(jià)值。由于beta多樣性格局具有尺度依賴(lài)的特點(diǎn),導(dǎo)致本研究存在一定程度的局限性。因此,今后的研究可以嘗試不同的取樣方法(例如大樣地監(jiān)測(cè))和更多的理論視角(如譜系、功能屬性等),將助益于有關(guān)群落構(gòu)建機(jī)制問(wèn)題深入闡釋。

致謝：野外工作得到了北京師范大學(xué)生命科學(xué)學(xué)院閆瑞亞、郝加琛、何毅等同學(xué)的大力支持,特此致謝。

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Patterns and determinants of beta diversity in the understory vegetation layers of montane boreal conifer forest in Luya Mountain

ZHAO Mingfei1,2, XING Kaixiong1,2, WANG Yuhang1,2, WANG Guoyi1,2, XUE Feng1,2, ZUO Wanyi1,2, KANG Muyi1,2,*

1StateKeyLaboratoryofEarthSurfaceProcessesandResourceEcology,BeijingNormalUniversity,Beijing100875,China2CollegeofResourcesScience&Technology,BeijingNormalUniversity,Beijing100875,China

Ecologists have long been enthusiastic about alpha diversity in montane regions; however, the elevational patterns of beta diversity and underlying crucial processes are still rarely studied. Niche and neutral processes are known to be two key factors in shaping species composition in a community. Although it could be difficult to test independently because of covariability, these two factors could produce competing predictions concerning the pattern of beta diversity between communities with environmental divergence and geographic distance. Our goal was to discover the patterns of species turnover among sites in temperate montane forests, and determine to what extent environmental filtering and limitation of dispersal affect the processes of species assembly. Additionally, we tried to pinpoint the main factors associated with niche filtering, which dominantly control the local floristic composition of the understory. We investigated the coniferous forest communities along the elevational gradient of Luya Mountain, documenting all species encountered and environmental conditions in 1720 m × 30 m plots. For all pairwise sites, we calculated the Simpson′s beta dissimilarity (beta-sim) of species composition and the Euclidean distances of independent variables (elevational, geographical, and environmental) for shrubs and herbs. The Mantel test and its partial version were adopted to analyze data, respectively. Linear trends of beta-sim against all ‘distances’ were obtained by ordinary least square regression. Furthermore, we employed canonical correspondence analysis (CCA) to demonstrate the relationship between species composition and the significant habitat descriptors selected through the Monte Carlo permutation test. The results showed that the turnover of herbaceous species between adjacent sampling sites exhibited a decreasing pattern along the elevational gradient, whereas the pattern of shrubs was irregular. For both shrubs and herbs, beta-sim increased significantly with both elevational and geographical distances, except the environmental distance. After controlling the influence of elevation by the partial Mantel test, the significant correlation between beta-sim and geographic distance was still maintained, but not vice versa. Results of CCA suggested that environmental factors together explained 74.4% of variance in understory species composition, and more specifically, litter thickness, slope, stem density, and basal area were indicated as key factors at the local scale. Nevertheless, there was no significant correlation between community structure and edaphic variables. We therefore concluded that environmental filtering and limitation of dispersal might jointly regulate the patterns of species beta diversity in the understory of boreal coniferous forest within Luya Mountain, with dispersal limitation playing a more important role in community assembly.

elevational gradient; species turnover; community assembly; dispersal limitations; niche filtering

國(guó)家自然科學(xué)基金 (41271059)；科技部科技基礎(chǔ)性工作專(zhuān)項(xiàng) (2011FY110300)

2016- 03- 05; 網(wǎng)絡(luò)出版日期:2017- 02- 17

10.5846/stxb201603050390

*通訊作者Corresponding author.E-mail: kangmy@bnu.edu.cn

趙鳴飛,邢開(kāi)雄,王宇航,王國(guó)義,薛峰,左婉怡,康慕誼.蘆芽山寒溫性針葉林冠層下植被beta多樣性格局及其成因.生態(tài)學(xué)報(bào),2017,37(10):3327- 3334.

Zhao M F, Xing K X, Wang Y H, Wang G Y, Xue F, Zuo W Y, Kang M Y.Patterns and determinants of beta diversity in the understory vegetation layers of montane boreal conifer forest in Luya Mountain.Acta Ecologica Sinica,2017,37(10):3327- 3334.