高寒草地植物物种多样性与功能多样性的关系

物种多样性与功能多样性的关系是生态学当前研究的热点问题之一,不同区域典型生态系统物种多样性和功能多样性的关系研究有利于生物多样性保护理论的全面发展。以青藏高原地区的主要草地生态系统—高寒草甸和高寒草原为研究对象,采用4个物种多样性指数(Patrick丰富度指数、Shannon-Weiner多样性指数、Pielou均匀度指数和Simpson优势度指数)和9个功能多样性指数(FAD功能性状距离指数、MFAD功能性状平均距离指数、基于样地的FDp和基于群落的FDc功能树状图指数、FRic功能体积指数、FEve功能均匀度指数、Rao功能离散度常二次熵指数、FDiv功能离散指数、FDis功能分散指数),分析了高寒草地植物物种多样性、功能多样性关系及其与初级生产力的关系,以期阐明3个科学问题:不同草地类型的高寒草地生态系统植物物种多样性和功能多样性有何差异?高寒草地生态系统的植物物种多样性和功能多样性有何关系?高寒草地生态系统物种多样性、功能多样性对生态系统功能的影响有何异同?研究结果表明:(1)与高寒草原相比,高寒草甸具有更高的物种多样性、功能丰富度和功能离散度;(2)高寒草甸中,Patrick丰富度与功能丰富度指数(FAD、MFAD、FDp、FDc)和功能离散度指数(FDiv)的具有较强的相关性,最优拟合方程分别为幂函数和二次多项式函数;(3)高寒草原中,Patrick丰富度与功能丰富度指数(FAD、MFAD、FDp、FDc、FRic)、Shannon指数和Simpson指数与FEve指数的相关性较强,最优拟合方程为二次多项式函数,Pielou指数与FEve指数的相关性较强,最优拟合方程为指数函数;(4)高寒草甸的初级生产力分别与物种丰富度指数Patrick、功能离散指数FDiv具有较强的相关性;而高寒草原的初级生产力与4个物种多样性指数间均具有较强的相关性,与功能离散指数FDiv具有较强的相关性,最佳拟合方程均为二次多项式函数。研究的总体结论为:物种多样性、功能多样性、二者之间的关系以及二者与生态系统服务功能(以初级生产力为例)之间的关系在高寒草甸和高寒草原群落中表现迥异,因此在研究青藏高原高寒草地的生态功能时,不能仅仅测度传统的物种多样性,还应测度与物种多样性、生态功能密切相关的功能多样性。     

High functional diversity in deep‐sea fish communities and increasing intraspecific trait variation with increasing latitude

Variation in both inter‐ and intraspecific traits affects community dynamics, yet we know little regarding the relative importance of external environmental filters versus internal biotic interactions that shape the functional space of communities along broad‐scale environmental gradients, such as latitude, elevation, or depth. We examined changes in several key aspects of functional alpha diversity for marine fishes along depth and latitude gradients by quantifying intra‐ and interspecific richness, dispersion, and regularity in functional trait space. We derived eight functional traits related to food acquisition and locomotion and calculated seven complementary indices of functional diversity for 144 species of marine ray‐finned fishes along large‐scale depth (50–1200 m) and latitudinal gradients (29°–51° S) in New Zealand waters. Traits were derived from morphological measurements taken directly from footage obtained using Baited Remote Underwater Stereo‐Video systems and museum specimens. We partitioned functional variation into intra‐ and interspecific components for the first time using a PERMANOVA approach. We also implemented two tree‐based diversity metrics in a functional distance‐based context for the first time: namely, the variance in pairwise functional distance and the variance in nearest neighbor distance. Functional alpha diversity increased with increasing depth and decreased with increasing latitude. More specifically, the dispersion and mean nearest neighbor distances among species in trait space and intraspecific trait variability all increased with depth, whereas functional hypervolume (richness) was stable across depth. In contrast, functional hypervolume, dispersion, and regularity indices all decreased with increasing latitude; however, intraspecific trait variation increased with latitude, suggesting that intraspecific trait variability becomes increasingly important at higher latitudes. These results suggest that competition within and among species are key processes shaping functional multidimensional space for fishes in the deep sea. Increasing morphological dissimilarity with increasing depth may facilitate niche partitioning to promote coexistence, whereas abiotic filtering may be the dominant process structuring communities with increasing latitude.     

新薛河底栖动物物种多样性与功能多样性研究

研究功能多样性与物种多样性关系及其随环境梯度的变化规律,有助于理解生物在群落中的共存机制;然而,二者间关系的研究在淡水生态学中尚鲜见报道。通过对新薛河典型河段(A缓流河段、B断流河段、C有机污染河段、D对照河段、E人为干扰河段)底栖动物季节性调查,就物种多样性和功能多样性时空动态及关系进行了研究。结果表明:在空间序列上,物种多样性指数在B河段均最低,表明间歇性断流对物种多样性影响重大。功能丰富度在D河段最高,A河段最低;功能均匀度在A河段高于其他河段;功能分离度在A、B河段最高,D河段最低。在时间序列上,物种丰富度和Shannon指数均值在10月份最低,4月份最高;均匀度指数在12月份最低,10月份最高。3个功能多样性指数于各季节间差异显著、相互独立,主要受水文条件和底栖动物生活史影响。相关分析表明,功能多样性指数间无显著相关性;功能丰富度同物种丰富度和Shannon指数相关显著,功能均匀度同物种均匀度相关显著。逐步回归分析发现,功能丰富度受物种丰富度和Shannon指数影响显著,功能均匀度受物种均匀度影响显著;功能多样性和物种多样性指数间拟合度总体不高。研究结果进一步表明:相对物种多样性,功能多样性对生境梯度变化响应更加全面。     

Functional regularity: a neglected aspect of functional diversity

Functional diversity has been identified as a key to understanding ecosystem and community functioning. However, due to the lack of a sound definition its nature and measurement are still poorly understood. In the same way that species diversity can be split into species richness and species evenness, so functional diversity can be split into functional richness (i.e. the amount of functional trait/character/attribute space filled) and functional evenness (i.e. the evenness of abundance distribution in functional trait space). We propose a functional regularity index (FRO) as a measure of functional evenness for situations where species are represented only by a single functional trait value (e.g. mean, median or mode), and species abundances are known. This new index is based on the Bulla O index of species evenness. When dealing with functional types or categorical functional traits, the Bulla O or any other accepted species evenness index may be used directly to measure functional evenness. The advantage of FRO is that it supplies a measure of functional evenness for continuous trait data. The FRO index presented in this paper fulfils all the a priori criteria required. We demonstrate with two example datasets that a range of FRO values may be obtained for both plant and animal communities. Moreover, FRO was strongly related to ecosystem function as seen in photosynthetic biomass in plant communities, and was able to differentiate sampling stations in a lagoon based on the functional traits of fish. Thus, the FRO index is potentially a highly useful tool for measuring functional diversity in a variety of ecological situations.     

Functional diversity (FD), species richness and community composition

Functional diversity is an important component of biodiversity, yet in comparison to taxonomic diversity, methods of quantifying functional diversity are less well developed. Here, we propose a means for quantifying functional diversity that may be particularly useful for determining how functional diversity is related to ecosystem functioning. This measure of functional diversity “FD” is defined as the total branch length of a functional dendrogram. Various characteristics of FD make it preferable to other measures of functional diversity, such as the number of functional groups in a community. Simulating species' trait values illustrates how the relative importance of richness and composition for FD depends on the effective dimensionality of the trait space in which species separate. Fewer dimensions increase the importance of community composition and functional redundancy. More dimensions increase the importance of species richness and decreases functional redundancy. Clumping of species in trait space increases the relative importance of community composition. Five natural communities show remarkably similar relationships between FD and species richness.     

Severe limitations of the FEve metric of functional evenness and some alternative metrics

The metric of functional evenness FEve is an example of how approaches to conceptualizing and measuring functional variability may go astray. This index has several critical conceptual and practical drawbacks:

1. Different values of the FEve index for the same community can be obtained if the species have unequal species abundances; this result is highly likely if most of the traits are categorical.
2. Very minor differences in even one pairwise distance can result in very different values of FEve.
3. FEve uses only a fraction of the information contained in the matrix of species distances. Counterintuitively, this can cause very similar FEve scores for communities with substantially different patterns of species dispersal in trait space.
4. FEve is a valid metric only if all species have exactly the same abundances. However, the meaning of FEve in such an instance is unclear as the purpose of the metric is to measure the variability of abundances in trait space.

We recommend not using the FEve metric in studies of functional variability. Given the wide usage of FEve index over the last decade, the validity of the conclusions based on those estimates is in question. Instead, we suggest three alternative metrics that combine variability in species distances in trait space with abundance in various ways. More broadly, we recommend that researchers think about which community properties (e.g., trait distances of a focus species to the nearest neighbor or all other species, variability of pairwise interactions between species) they want to measure and pick from among the appropriate metrics.     

高寒草甸种间性状差异和物种均匀度对物种多样性与功能多样性关系的影响

物种多样性(SD)与功能多样性(FD)之间存在多种关系,但由于生态系统功能主要由物种的功能属性决定,因而功能多样性对生态系统功能的影响大于物种多样性的影响。但在种间性状差异和物种均匀度这两个构成功能多样性的基本成分中,何者对功能多样性影响更大,并进而决定SD-FD关系尚不明确。通过在高寒矮嵩草(Kobresia humilis)草甸为期6a的刈割(留茬1 cm、3 cm及不刈割)和施肥(尿素7.5 g m~(-2)a~(-1)+磷酸二胺1.8 g m~(-2)a~(-1)、不施肥)控制实验,研究了种间性状差异(33个物种13个性状)和物种均匀度(所有物种)对物种多样性(所有物种)与功能多样性(33个物种13个性状)之间关系的影响。研究结果显示:(1)物种多样性与功能多样性正相关,它们与多性状种间差异负相关,而与物种均匀度正相关。物种均匀度是导致功能多样性变化的主要因素,也是导致SD-FD正相关的原因,这是因为随着物种多样性增加,物种均匀度的增加程度大于多性状种间差异的减少程度,因而功能多样性增加,SD-FD正相关;(2)功能多样性指数(FD_(Rao)和FDis)随物种多样性指数(H')减速递增,表明群落存在一定的功能冗余,且功能冗余随物种多样性的增大而增大,但尚未达到产生SD-FD无相关性的极限H'值;(3)功能多样性对高寒草甸生态系统地上净初级生产力(ANPP)的影响大于物种多样性的影响,二元线性回归显示在同时考虑二者对ANPP的影响时,可排除物种多样性的作用。但由于物种多样性下降或物种丧失引起的物种功能性状丢失或性状空间维度减小将导致功能多样性降低,表明它们之间存在一定互补性,在研究生物多样性与生态系统功能关系时,同时考虑物种多样性和功能多样性的影响仍十分必要。     

Remotely sensed between‐individual functional trait variation in a temperate forest

1. Trait‐based ecology holds the promise to explain how plant communities work, for example, how functional diversity may support community productivity. However, so far it has been difficult to combine field‐based approaches assessing traits at the level of plant individuals with limited spatial coverage and approaches using remote sensing (RS) with complete spatial coverage but assessing traits at the level of vegetation pixels rather than individuals. By delineating all individual‐tree crowns within a temperate forest site and then assigning RS‐derived trait measures to these trees, we combine the two approaches, allowing us to use general linear models to estimate the influence of taxonomic or environmental variation on between‐ and within‐species variation across contiguous space.
2. We used airborne imaging spectroscopy and laser scanning to collect individual‐tree RS data from a mixed conifer‐angiosperm forest on a mountain slope extending over 5.5 ha and covering large environmental gradients in elevation as well as light and soil conditions. We derived three biochemical (leaf chlorophyll, carotenoids, and water content) and three architectural traits (plant area index, foliage‐height diversity, and canopy height), which had previously been used to characterize plant function, from the RS data. We then quantified the contributions of taxonomic and environmental variation and their interaction to trait variation and partitioned the remaining within‐species trait variation into smaller‐scale spatial and residual variation. We also investigated the correlation between functional trait and phylogenetic distances at the between‐species level. The forest consisted of 13 tree species of which eight occurred in sufficient abundance for quantitative analysis.
3. On average, taxonomic variation between species accounted for more than 15% of trait variation in biochemical traits but only around 5% (still highly significant) in architectural traits. Biochemical trait distances among species also showed a stronger correlation with phylogenetic distances than did architectural trait distances. Light and soil conditions together with elevation explained slightly more variation than taxonomy across all traits, but in particular increased plant area index (light) and reduced canopy height (elevation). Except for foliage‐height diversity, all traits were affected by significant interactions between taxonomic and environmental variation, the different responses of the eight species to the within‐site environmental gradients potentially contributing to the coexistence of the eight abundant species.
4. We conclude that with high‐resolution RS data it is possible to delineate individual‐tree crowns within a forest and thus assess functional traits derived from RS data at individual level. With this precondition fulfilled, it is then possible to apply tools commonly used in field‐based trait ecology to partition trait variation among individuals into taxonomic and potentially even genetic variation, environmental variation, and interactions between the two. The method proposed here presents a promising way of assessing individual‐based trait information with complete spatial coverage and thus allowing analysis of functional diversity at different scales. This information can help to better understand processes shaping community structure, productivity, and stability of forests.

     

高寒草甸不同坡向植物群落物种多样性与功能多样性的关系

植物群落物种多样性与功能多样性是生态学研究的热点问题之一,研究其对于保护生物多样性和维持生态系统功能具有重要意义。采用野外群落调查方法,探讨了物种多样性与功能多样性在坡向梯度上的变化格局及其关联性。结果显示：（1）从北坡到南坡,土壤含水量、有机碳呈递减趋势;坡度、照度、土温、pH呈递增趋势;土壤全氮、全磷在西坡明显低于其他各坡向;（2）物种多样性指数均由北坡向南坡依次递减;（3）一元性状功能多样性在各坡向间的差异显著（P<0.05）,除LDMC_FDrao外,其他功能性状均为北坡大于南坡;（4）多元性状功能丰富度与功能均匀度均由北坡向南坡呈递减的趋势,各坡向的功能均匀度差异性不显著。通过相关分析与通径分析发现,功能多样性指数的主要环境决定因子与限定因子均存在差异：功能丰富度、功能均匀度主要环境限定因子为pH,功能离散度主要环境限定因子为土温;功能离散度主要环境决定因子为土壤含水量;（5）物种多样性指数与功能丰富度呈正线性相关,与功能离散度呈负线性相关,而与功能均匀度不相关。     

Taxonomic and functional diversity covary in rock pool microalgal communities despite their different drivers

Local biodiversity has traditionally been estimated with taxonomic diversity metrics such as species richness. Recently, the concept of biodiversity has been extended beyond species identity by ecological traits determining the functional role of a species in a community. This interspecific functional diversity typically responds more strongly to local environmental variation compared with taxonomic diversity, while taxonomic diversity may mirror more strongly dispersal processes compared with functional metrics. Several trait‐based indices have been developed to measure functional diversity for various organisms and habitat types, but studies of their applicability on aquatic microbial communities have been underrepresented. We examined the drivers and covariance of taxonomic and functional diversity among diatom rock pool communities on the Baltic Sea coast. We quantified three taxonomic (species richness, Shannon''s diversity, and Pielou''s evenness) and three functional (functional richness, evenness, and divergence) diversity indices and determined abiotic factors best explaining variation in these indices by generalized linear mixed models. The six diversity indices were highly collinear except functional evenness, which merely correlated significantly with taxonomic evenness. All diversity indices were always explained by water conductivity and temperature–sampling month interaction. Taxonomic diversity was further consistently explained by pool distance to the sea, and functional richness and divergence by pool location. The explained variance in regression models did not markedly differ between taxonomic and functional metrics. Our findings do not clearly support the superiority of neither set of diversity indices in explaining coastal microbial diversity, but rather highlight the general overlap among the indices. However, as individual metrics may be driven by different factors, the greatest advantage in assessing biodiversity is nevertheless probably achieved with a simultaneous application of the taxonomic and functional diversity metrics.     

On the relationship between Pielou’s evenness and landscape dominance within the context of Hill’s diversity profiles

Entropy-related biodiversity indices deriving their conceptual basis from Shannon’s information theory have a long history of use in ecology for quantifying community structure and diversity. In addition, in the last two decades, numerous information–theoretical indices, such as the landscape dominance index, have been extensively applied to characterize landscape diversity in space and time. In this contribution, we offer a simple analytical relation between Pielou’s evenness J and landscape dominance D within the broader context of Hill’s parametric diversity family. Within this context, we recommend the use of Hill’s diversity number evenness E_1,0 to overcome the shortcomings both of Pielou’s evenness J and the landscape dominance index D.     

井冈山鹿角杜鹃群落灌木层功能多样性及其随海拔梯度的变化

研究植物群落功能多样性沿环境梯度的变化可以揭示功能多样性与生态系统功能间的关系及维持机制。以井冈山地区鹿角杜鹃（Rhododendron latoucheae）群落为研究对象,通过调查不同海拔梯度群落灌木层植物的物种组成与结构特征,研究了该群落类型灌木层植物的物种多样性、功能多样性、环境因子的特征及其相互之间的关系。结果表明：1）群落类型灌木层植物物种多样性和功能多样性沿海拔梯度呈现不同的变化趋势。物种多样性指数均随着海拔的升高呈减小趋势,而功能多样性指数的变化却较为复杂。其中FRic、FEve和FDis随着海拔的升高显著减小,FDiv和Rao却随海拔的升高而增加;2）群落中物种多样性和功能多样性呈现复杂的相关性。FRic、FEve与丰富度指数呈显著正相关,而Rao、FDis、FDiv与Simpson优势度指数呈线性相关关系,且具有显著相关性;3）群落所分布的坡位及土壤氮与磷含量等环境因子对灌木植物的功能多样性有着重要的影响。鹿角杜鹃群落灌木层植物的物种多样性和功能多样性的相互关系及其对环境变化的响应共同决定了群落的生态系统功能。     

山西五鹿山森林群落木本植物功能多样性

通过选取群落中木本植物种子的扩散方式、传粉方式、植株高度和盖度等13个功能性状,计算出群落的6个功能多样性指数:功能性状距离、功能性状平均距离、功能体积、功能均匀度、功能分散指数和Rao二次熵指数,结合群落物种丰富度指数、Shannon-Wiener指数和物种均匀度指数对山西五鹿山森林群落木本植物功能多样性进行研究。结果表明:(1)功能性状距离、功能性状平均距离、功能体积与物种丰富度、Shannon-Wiener指数显著正相关;功能均匀度与Shannon-Wiener指数、物种均匀度指数显著正相关;功能分散指数、Rao二次熵指数与物种均匀度指数、Shannon-Wiener指数显著正相关;(2)功能多样性的差异很大程度上是由于物种差异所引起的;(3)6个功能多样性指数可分为三类:功能性状距离、功能性状平均距离、功能体积为功能丰富度指数;功能均匀度为功能均匀度指数;功能分散指数和Rao二次熵指数为功能离散度指数。该分类结果符合指数的计算方法和生态学意义,以及相互独立的标准。     

Diversity investigation by application of DNA barcoding: A case study of lepidopteran insects in Xinjiang wild fruit forests,China

To investigate the species diversity of lepidopteran insects in Xinjiang wild fruit forests, establish insect community monitoring systems, and determine the local species pool, we test the applicability of DNA barcoding based on cytochrome c oxidase subunit I (COI) gene for accurate and rapid identification of insect species. From 2017 to 2019, a total of 212 samples with ambiguous morphological identification were selected for DNA barcoding analysis. Five sequence‐based methods for species delimitation (ABGD, BINs, GMYC, jMOTU, and bPTP) were conducted for comparison to traditional morphology‐based identification. In total, 2,422 samples were recorded, representing 143 species of 110 genera in 17 families in Lepidoptera. The diversity analysis showed that the richness indices for Noctuidae was the highest (54 species), and for Pterophoridae, Cossidae, Limacodidae, Lasiocampidae, Pieridae, and Lycaenidae were the lowest (all with 1 species). The Shannon–Wiener species diversity index (H′) and Pielou''s evenness (J′) of lepidopteran insects first increased and then decreased across these 3 years, while the Simpson diversity index showed a trend of subtracted then added. For molecular‐based identification, 67 lepidopteran species within 61 genera in 14 families were identified through DNA barcoding. Neighbor‐joining (NJ) analysis showed that conspecific individuals were clustered together and formed monophyletic groups with a high support value, except for Lacanobia contigua (Denis & Schiffermüller, 1775) (Noctuidae: Hadeninae). Sixty‐seven morphospecies were classified into various numbers of MOTUs based on ABGD, BINs, GMYC, jMOTU, and bPTP (70, 96, 2, 71, and 71, respectively). In Xinjiang wild fruit forests, the family with the largest number of species is Noctuidae, followed by Geometridae, Crambidae, and the remaining families. The highest Shannon diversity index is observed for the family Noctuidae. Our results indicate that the distance‐based methods (ABGD and jMOTU) and character‐based method (bPTP) outperform GMYC. BINs is inclined to overestimate species diversity compared to other methods.     

山西七里峪茶条槭群落特征及物种多样性研究

运用TWINSPAN对山西七里峪茶条槭群落类型进行划分,并采用Patrick指数、Simpson指数、Shannon-Wiener指数、Alatalo指数研究群落的物种多样性。结果表明:TWINSPAN将茶条槭群落的73个样方划分为10个群丛;各群丛的物种丰富度指数、多样性指数和均匀度指数之间存在差异,群丛Ⅲ和Ⅶ的丰富度指数和多样性指数较高,群丛Ⅰ的多样性指数较低;各群丛乔木层、灌木层和草本层之间的物种多样性也存在差异,多样性指数大致表现为草本层高于灌木层高于乔木层。土壤中的有机质、速效钾、含水量是影响茶条槭群落物种多样性的主要因素。     

Tree species richness decreases while species evenness increases with disturbance frequency in a natural boreal forest landscape

Understanding species diversity and disturbance relationships is important for biodiversity conservation in disturbance‐driven boreal forests. Species richness and evenness may respond differently with stand development following fire. Furthermore, few studies have simultaneously accounted for the influences of climate and local site conditions on species diversity. Using forest inventory data, we examined the relationships between species richness, Shannon''s index, evenness, and time since last stand‐replacing fire (TSF) in a large landscape of disturbance‐driven boreal forest. TSF has negative effect on species richness and Shannon''s index, and a positive effect on species evenness. Path analysis revealed that the environmental variables affect richness and Shannon''s index only through their effects on TSF while affecting evenness directly as well as through their effects on TSF. Synthesis and applications. Our results demonstrate that species richness and Shannon''s index decrease while species evenness increases with TSF in a boreal forest landscape. Furthermore, we show that disturbance frequency, local site conditions, and climate simultaneously influence tree species diversity through complex direct and indirect effects in the studied boreal forest.     

佛坪国家级自然保护区植物群落物种多样性特征

用物种多样性指数（Simpson指数和Shannon指数）、均匀度指数（Pielou均匀度）和物种丰富度,对佛坪国家级自然保护区主要高等植物群落物种多样性进行了测度。结果表明：森林群落的多样性程度高于灌丛和草甸,落叶阔叶林高于针叶林,栎林高于杨桦林。群落物种多样性有随海拔高度的升高而降低的趋势。物种多样性在森林群落垂直结构上的分布特点,表现为一般乔木层与灌木层接近但低于草本层。     

Functional richness: Overview of indices and underlying concepts

Functional richness, currently defined as the amount of niche space occupied by the species within a community, is one of the three major components of functional diversity. Different indices have been developed in order to quantify this component. However, the range of indices available for assessing functional richness, often mathematically complex and based on different rationales, can cause confusion for field ecologists and lead to misinterpretation of the results obtained. In this context, we have provided the first study exclusively focused on the comparison of the definitions, advantages and drawbacks of a large set of functional richness indices. The first part of this work is focused on four indices (FD_P&G, FRic, TOP and N-hypervolumes indices) that are currently the most commonly used for assessing functional richness. We have completed our study by including recently developed indices that enable us to take into account the intraspecific trait variability (i.e. FRim index and TDP framework), because there is currently a growing scientific consensus regarding the necessity of including this aspect in the assessment of the functional diversity of communities.We demonstrate that although authors have argued that their index describes the functional richness, each of them describes only part of it, and this part may strongly differ from one index to another. Rather than advocating the general use of a single index and/or systematically avoiding others, our study highlights the need for selecting indices in close relation with the context, the available data and the aims of each study. Such a strategy is an essential preliminary step for preventing misunderstanding and artefactual controversies. Along these lines, we propose some guidelines to help users in selecting the most appropriate indices according both to the facet of functional richness on which they wish to focus and to the characteristics of the available data.     

停止人为去除植物功能群后的高寒草甸多样性恢复过程与群落构建

已有大量研究利用功能性状或系统发育来推断群落构建机制, 然而不同过程可能会导致相似的格局。本文基于对甘南高寒草甸植物功能群去除处理后群落恢复过程的跟踪调查, 对比了物种多样性、功能多样性和系统发育多样性的动态变化, 并分析了物种定殖与消失过程对功能多样性和系统发育多样性变化的影响。结果表明: 去除不同数量功能群的群落中: (1)包括物种丰富度(SR)、Shannon-Wiener指数(H°)和Simpson指数(D)在内的传统物种多样性均随时间快速上升并与自然群落趋同, 不同群落的均匀度指数(J)随时间呈增加趋势并趋于相似; 功能多样性(FD)与系统发育多样性(PD)呈现出与物种多样性相似的动态变化趋势, 而平均配对距离(MPD/MPD_a、MFD/MFD_a)则向中等程度聚集。(2)不同群落的功能群和物种组成在短期内均恢复到与自然群落非常相似的程度。(3)物种定殖与消失过程的功能格局是群落恢复过程中趋同效应的主要驱动力。本研究揭示了高寒草甸植物功能群去除停止后群落短期内快速恢复的过程, 说明在小尺度且周边具有大范围未退化草甸的情况下, 无论物种多样性、功能多样性还是系统发育多样性都具有较快的恢复能力, 同时说明了利用群落系统发育多样性格局来推断群落构建机制的局限性。     

羌塘高寒草地物种多样性与生态系统多功能关系格局

传统的生物多样性-生态系统功能研究大多侧重于单一生态系统功能与物种多样性的关系,忽略了生态系统的重要价值在于其能够同时提供多种功能或服务,即生态系统的多功能性。基于藏北羌塘高寒草地样带调查数据,选取植被地上生物量、地下生物量、土壤全氮、硝态氮及铵态氮含量、土壤全磷含量、土壤有机碳储量等7个与植物生长、养分循环、土壤有机碳蓄积相关的参数来表征生态系统多功能性。采用上述参数转换为Z分数后的平均值计算多功能性指数(M)。分析了不同生物多样性指数与生态系统多功能指数的关系以及年降水量和年均温度对物种多样性和生态系统多功能性指数的影响。结果表明,物种丰富度指数与生态系统多功能性之间呈极显著的正相关关系,Shannon-wiener和Simpson物种多样性指数也与多功能性指数间呈显著的正相关,但多功能性指数与Pielou均匀度指数没有表现出明显的相关关系。物种丰富度与表征植物生长、养分循环以及土壤有机碳蓄积的生态系统功能指数间也均呈极显著的正相关关系。降水格局显著影响羌塘高原物种丰富度和生态系统多功能指数,二者均随年降雨量的增加而显著增加,但物种多样性指数并未与年降水量呈现显著相关关系。研究强调了群落物种丰富度即群落物种数量对维持生态系统多功能性的重要意义,这意味着由于人类活动导致的物种丧失可能会给藏北高寒草地生态系统多功能和生态服务带来更为严重的后果。就退化草地恢复或草地可持续管理而言,在藏北羌塘地区,本地植物种的物种丰富度恢复和维持应作为重要目标之一。