From plots to islands: species diversity at different scales

Aim To investigate how plant diversity of whole islands (‘gamma’) is related to alpha and beta diversity patterns among sampling plots within each island, thus exploring aspects of diversity patterns across scales. Location Nineteen islands of the Aegean Sea, Greece. Methods Plant species were recorded at both the whole‐island scale and in small 100 m² plots on each island. Mean plot species richness was considered as a measure of alpha diversity, and six indices of the ‘variation’‐type beta diversity were also applied. In addition, we partitioned beta diversity into a ‘nestedness’ and a ‘replacement’ component, using the total species richness recorded in all plots of each island as a measure of ‘gamma’ diversity. We also applied 10 species–area models to predict the total observed richness of each island from accumulated plot species richness. Results Mean alpha diversity was not significantly correlated with the overall island species richness or island area. The range of plot species richness for each island was significantly correlated with both overall species richness and area. Alpha diversity was not correlated with most indices of beta diversity. The majority of beta diversity indices were correlated with whole‐island species richness, and this was also true for the ‘replacement’ component of beta diversity. The rational function model provided the best prediction of observed island species richness, with Monod’s and the exponential models following closely. Inaccuracy of predictions was positively correlated with the number of plots and with most indices of beta diversity. Main conclusions Diversity at the broader scale (whole islands) is shaped mainly by variation among small local samples (beta diversity), while local alpha diversity is not a good predictor of species diversity at broader scales. In this system, all results support the crucial role of habitat diversity in determining the species–area relationship.     

Landscape structure and management regime as indicators of calcareous grassland habitat condition and species diversity

This study investigates the importance of spatial landscape characteristics and habitat management on the condition of calcareous grassland in the North Down Natural Area, Kent UK. We used a digitised map of the study area containing shapefiles of all the habitats including 82 patches of calcareous grassland together with management information for each patch and data on the presence and abundance of a range of calcareous grassland indicator plant species. We defined habitat condition by presence of indicator species and used classification trees to generate models with rules for predicting habitat condition from the landscape spatial characteristics and management information. We also applied the same method to investigate the factors affecting presence or diversity of three ecological groups of positive indicator species and dominance of a negative indicator species. All the models except one showed good classification accuracy and high kappa statistic. Favourable habitat condition was predicted by presence of different types of grazing management, presence of woodland around patches of calcareous grassland and shape complexity. These results indicate that calcareous grassland in favourable condition is management-dependent but also located in less intensively managed landscapes. Unfavourable habitat condition was predicted by threat factors such as lack of management and high incidence of arable or improved grassland around patches of calcareous grassland, indicating nutrient enrichment and habitat degradation. Some of these factors also predicted high diversity of the different ecological species groups. The value of this method for predicting habitat condition and species diversity from baseline ecological data for conservation monitoring at the landscape level is emphasised.     

麦积山风景区不同生境类型蝶类的多样性

于2003~2004年对麦积山地区不同生境类型中蝴蝶多样性进行调查研究。依据海拔高度、气候、土壤和植被的不同将该地区的蝴蝶生境划分为3种类型:林缘山地、森林林地、裸岩。共收集蝴蝶3950只,隶属8科43属64种。计算了3种生境类型中蝶类物种丰富度、相似性系数、多样性指数。其中,蝴蝶物种丰富度由大到小为森林林地(8·8359)>林缘山地(6·1442)>裸岩(1·4711),物种多样性指数由大到小为森林林地(H'=1·4068)>裸岩(H'=0·9746)>林缘山地(H'=0·9201);森林林地和林缘山地的相似性系数最高(0·2221),其次是林缘山地和裸岩(0·0869),森林林地和裸岩相似性系数最低(0·0656)。     

青海祁连地区不同生境类型蝶类多样性研究

于1997－1999年对青海祁连地区不同生境类型中蝴蝶多样性进行了研究。研究中依据海拔高度、气候、土壤和植被的不同将该地区的蝴蝶生境划分为5种类型：山缘农田、山地草原、森林草原、高寒灌丛草甸、裸岩。共收集蝴蝶4367只,隶属于6科35属53种,计算了5种生境类型中蝶类物种丰富度、相似性系数、多样性指数,其中,蝶类物种丰富度由小到大的顺序为：裸岩（6种）＜山地草原（13种）＜森林草原（14种）＜高寒灌丛草甸（22种）＜山缘农田（H′＝2.7071）、高寒灌丛草甸（H′=2.7734）;森林草原和山缘农田的相似性系数最高（0.3704）,其次为山地草原和高寒灌丛草甸（0.2500,裸岩与其他生境类型的相似性系数最低。     

Avian species diversity in different habitat types in and around North Nandi Forest,Kenya

Forest fragmentation and degradation leads to formation of modified habitats whose ability to support existing avifaunal diversity is still largely unknown. Bird diversity in indigenous forest, disturbed forest, plantation forest and farmlands adjacent to North Nandi Forest reserve was studied between January 2015 and June 2015. The distribution of bird feeding guilds in these habitat patches was also evaluated. Birds were surveyed using point counts, timed species counts and line transects and classified into six feeding guilds. A total of 3,232 individual birds of 151 species were recorded in the four habitats. Significant difference on bird abundance across the four habitats (F = 15.141, P ≤ 0.05, df = 3, 1121) was noted. Shannon–Weiner diversity index H′ for bird community ranged from 3.06 for plantation forest to 4.05 for disturbed forest showing a relatively diverse bird community. Insectivores (F = 3.090, P ≤ 0.05, df = 3, 297) dominated the foraging species assemblage in all the habitats significantly. Linear regression analysis revealed a strong linear relationship on bird species richness and abundance with vegetation variables (P < 0.01 in all cases). The results indicate that disturbed forest and indigenous forest support high bird species richness than plantation forest and farmlands. However, high bird abundance was observed in farmlands and plantation forest as opposed to indigenous forest and disturbed forest as they provide dispersal routes over a short distance and are important for creating corridors between primary forests.     

How species diversity responds to different kinds of human-caused habitat destruction

Human-caused habitat destruction, the major cause of species diversity losses, can be classified into two basic types, instantaneous destruction and continuous destruction. Thus, a universal model should be established to simulate and forecast the effects of different kinds of habitat destruction on species diversity during different historical periods. In this paper, we explore a multi-time-scale n-species model to study and compare species responses to instantaneous and continuous destruction. We find that (1) under instantaneous destruction, there are two different mechanisms of species extinction: one is a time-delayed deterministic extinction of superior competitors in order from the best to the poorest; the other is the extinction in a short time of inferior competitors. The survivors will experience three phases: decline, adjustment, and equilibrium. (2) When the total amounts of habitat destruction for both instantaneous and continuous cases are equal, the oscillation amplitudes of species abundances under instantaneous destruction are much greater than under continuous destruction, especially for inferior competitors, which make inferior competitors under instantaneous destruction more prone to stochastic extinction. Therefore instantaneous destruction is more detrimental to the survival of inferior competitors. (3) Under continuous destruction with habitat eventually being destroyed completely, there also are two types of species extinction mechanisms: the first is extinction in order from the best competitors to the poorest before complete destruction; the second is collective extinction due to complete destruction.     

Genetic diversity of Lotus corniculatus in relation to habitat type,species composition and species diversity

The genetic variability of Lotus corniculatus, a common and important fodder legume, was studied in relation to habitat type and to species diversity at a local level. The study was conducted in Cholomontas mountain, northern Greece, at altitudes of 760–870 m. Genetic material was selected from four forested, at the edge of forest, and four open grassland sites, and was studied with the aid of ISSR molecular markers. The plant cover at each study site was measured and the floristic composition was estimated. The percentage of graminoides increased in grassland sites with high grazing intensity, while the abundance of legumes, including L. corniculatus, forbs and woody species, increased in forested sites with low grazing intensity. Gene diversity H_E within the studied populations of L. corniculatus ranged from 0.167 to 0.213 and Shannon index (I) from 0.269 to 0.340. Genetic differentiation was detected between habitats as well as among the populations in each habitat, although it was low, 3% and 7% respectively. However, genetic differentiation was significant within the populations (90%). Genetic diversity of L. corniculatus was not correlated with species diversity (richness and evenness) either within or between populations, while was negatively correlated with L. corniculatus abundance.     

The surrogacy potential of white-tailed sea eagle nesting habitat on islands of the Baltic Sea

In order to tackle the current biodiversity crisis, a plethora of tempting shortcuts, such as the surrogate species approach, have recently been used to pinpoint important areas for protection. At the same time, species-specific conservation programmes are implemented in order to ameliorate the status of target threatened species. In the cases where species-specific programmes are evaluated and found to provide no apparent benefit to the target species, it is important to evaluate whether such conservation efforts may benefit other taxa sharing the same landscape with the target species. Here we assess the surrogacy potential of white-tailed sea eagle (WTSE) nesting habitat as indicator of biodiversity richness (using vascular plants and fungi as surrogated taxa) on islands of the Archipelago Sea in South-western Finland. We compared species richness on islands with and without a WTSE nest. We found weak evidence that islands with a WTSE nest support higher richness of vascular plants than islands without a nest. Conversely, we found no evidence that WTSE nests could be valid surrogates for fungi species inhabiting old-growth forests. Within the spatio-temporal and ecological limits of the present study, we suggest that the nesting habitat of WTSE may hold some surrogate potential for taxa, such as vascular plants, that may indicate high habitat diversity. This finding however remains to be confirmed. At the same time, it appears evident that the WTSE nesting habitat has poor surrogate potential with regards to old-growth forests. Overall, our findings line up with a growing body of other studies calling for caution and careful evaluation of the surrogacy efficiency of single species.     

甘肃小陇山林区不同生境类型蝶类多样性研究

于2006～2008年对甘肃小陇山林区不同生境类型中蝴蝶多样性进行了调查研究,研究中依据植被的不同将该林区的蝴蝶生境划分为6种类型:人工林、灌木丛和次生林、居民农田、针阔混交林、落叶阔叶林、针叶林。共获得蝴蝶标本5365只,隶属于11科116属210种。计算了6种生境类型中蝶类物种丰富度、相似性系数和多样性指数。不同生境中,灌木丛和次生林蝶类物种的多样性指数、丰富度和个体数量较高,人工林物种多样性指数、丰富度和个体数量较低;人工林与针叶林之间的相似性系数(0.4194)最高,针阔混交林与落叶阔叶林的相似性系数(0.2951)次之,人工林与灌木丛和次生林之间的相似性系数(0.0769)最低,表明各生境之间蝶类相似性系数很低。     

Animal species diversity driven by habitat heterogeneity/diversity: the importance of keystone structures

Aim In a selected literature survey we reviewed studies on the habitat heterogeneity–animal species diversity relationship and evaluated whether there are uncertainties and biases in its empirical support. Location World-wide. Methods We reviewed 85 publications for the period 1960–2003. We screened each publication for terms that were used to define habitat heterogeneity, the animal species group and ecosystem studied, the definition of the structural variable, the measurement of vegetation structure and the temporal and spatial scale of the study. Main conclusions The majority of studies found a positive correlation between habitat heterogeneity/diversity and animal species diversity. However, empirical support for this relationship is drastically biased towards studies of vertebrates and habitats under anthropogenic influence. In this paper, we show that ecological effects of habitat heterogeneity may vary considerably between species groups depending on whether structural attributes are perceived as heterogeneity or fragmentation. Possible effects may also vary relative to the structural variable measured. Based upon this, we introduce a classification framework that may be used for across-studies comparisons. Moreover, the effect of habitat heterogeneity for one species group may differ in relation to the spatial scale. In several studies, however, different species groups are closely linked to ‘keystone structures’ that determine animal species diversity by their presence. Detecting crucial keystone structures of the vegetation has profound implications for nature conservation and biodiversity management.     

A contribution to the knowledge of myxomycetes diversity in volcanic islands

A list of myxomycetes collected in Pantelleria, a volcanic island located 110 km southwest of the island of Sicily (Italy), is presented with data on distribution. Forty-nine taxa were identified, 38 of which are new for Sicily. The myxomycete diversity of Pantelleria was also compared with that of other volcanic islands located in the Atlantic and Pacific oceans.     

京津冀太行山片区不同生境昆虫种类和群落多样性调查与分析

通过对京津冀太行山片区不同生境昆虫群落多样性调查,为京津冀太行山片区生物多样性的保育和决策提供科学依据。在2019年7月-2020年10月,在京津冀太行山片区的9个县(区)(包括北京市的昌平区和房山区,以及河北省的涿鹿县、蔚县、涞水县、涞源县、易县、唐县和阜平县)的6种生境(即森林、人造林、湿地、灌丛、草地和农田)共设置106个样点,具体采用“样线踏查法”和“马来氏网法”相结合共进行了6次昆虫调查。共采集昆虫62 450头,隶属于14目153科608种。不同生境间昆虫的Margalef丰富度指数(P<0.01)、多样性指数H(P<0.01)和均匀度指数E(P<0.05)存在显著或极显著差异。Margalef丰富度指数依次为森林>人造林>湿地>灌丛>农田>草地,且森林的Margalef丰富度指数最高为5.64、草地最低为2.70;多样性指数H依次为草地>灌丛>湿地>农田>森林=人造林;均匀度指数E依次为草地>森林>灌丛>湿地>农田>人造林。不同生境之间昆虫种群相似度分析表明,森林和人造林...     

不同类型人工阔叶红松林高等植物物种多样性

采用Shahnon—Wiener多样性指数、均匀度指数和优势度指数等指标研究了辽宁东部山区人工营造20年生5种阔叶树水曲柳、刺愀、紫椴、色赤汤、白桦与红松形成的混交林及人工红松纯林内各层次高等植物物种多佯性,并对该6种林分的垂直结构进行比较。结果表明,人工阔叶红松混交林内植物种类丰富,数量较多;红松纯林内的植物种数仅为人工阔叶红松混交林的42％～52％,植物总数量只有混交林的11％～37％。人工阔叶红松林各层次高等植物物种多样性均好于人工红松纯林,但与原始阔叶红松林相比。人工阔叶红松林的物种多样性还较低。在林分垂直结构方面,人工阔叶红松混交林的成层现象明显,层次结构复杂,垂直多样性丰富;红松纯林只有1个主林冠层,灌木层、草本层较矮,林分垂直结构单一。     

Genetic diversity of Potamogeton pectinatus L. in relation to species diversity in a pair of lakes of contrasting trophic levels

Understanding the correlation between genetic diversity and species diversity in freshwater communities is important to elucidate the influences of local selective forces on the genetic diversity of local aquatic plant populations across different communities. This study employed amplified fragment length polymorphism (AFLP) to assess the genetic diversity of Potamogeton pectinatus L. populations between two sister-lakes with contrasting trophic levels, eutrophic and oligotrophic, in the Yunnan Plateau in southwest of China. The results showed high genetic differentiation between eutrophic lake and oligotrophic lake. The genetic distances between P. pectinatus populations were significantly correlated with the species evenness, but not with difference in species richness of aquatic plant communities. The results underpinned that genetic diversity at inter-population levels and local species diversity in plant communities are positively correlated. In addition, our results also suggested that habitat types might play an important role in the genetic diversity of the P. pectinatus populations between these two lakes.     

扎龙湿地不同生境的昆虫多样性

为了探讨湿地不同生境对昆虫物种多样性的影响,对扎龙湿地8种生境的昆虫进行了系统调查.共捕获昆虫5822只,分属11目58科143种,其中直翅目、双翅目、蜻蜒目为扎龙湿地的优势类群.不同生境中,草原草甸昆虫多样性最高,湖边生境多样性指数和均匀度指数均较高,杂草甸均最低.聚类分析和主分量分析结果表明,不同生境的昆虫群落相似性与水资源状况和植被类型有关,捕食性类群种类数和个体数量对昆虫群落稳定性具有重要的调控作用.湖边生境昆虫群落稳定性最强,湿草甸稳定性最弱.湿地水资源状况能影响昆虫生存生境,进而影响昆虫群落的组成和分布格局.     

The contribution of cacao agroforests to the conservation of lower canopy ant and beetle diversity in Indonesia

The ongoing destruction of tropical rainforests has increased the interest in the potential value of tropical agroforests for the conservation of biodiversity. Traditional, shaded agroforests may support high levels of biodiversity, for some groups even approaching that of undisturbed tropical forests. However, it is unclear to what extent forest fauna is represented in this diversity and how management affects forest fauna in agroforests. We studied lower canopy ant and beetle fauna in cacao agroforests and forests in Central Sulawesi, Indonesia, a region dominated by cacao agroforestry. We compared ant and beetle species richness and composition in forests and cacao agroforests and studied the impact of two aspects of management intensification (the decrease in shade tree diversity and in shade canopy cover) on ant and beetle diversity. The agroforests had three types of shade that represented a decrease in tree diversity (high, intermediate and low diversity). Species richness of ants and beetles in the canopies of the cacao trees was similar to that found in lower canopy forest trees. However, the composition of ant and beetle communities differed greatly between the agroforest and forest sites. Forest beetles suffered profoundly from the conversion to agroforests: only 12.5% of the beetle species recorded in the forest sites were also found in the agroforests and those species made up only 5% of all beetles collected from cacao. In contrast, forest ants were well represented in agroforests, with 75% of all species encountered in the forest sites also occurring on cacao. The reduction of shade tree diversity had no negative effect on ants and beetles on cacao trees. Beetle abundances and non-forest ant species richness even increased with decreasing shade tree diversity. Thinning of the shade canopy was related to a decrease in richness of forest ant species on cacao trees but not of beetles. The contrasting responses of ants and beetles to shade tree management emphasize that conservation plans that focus on one taxonomic group may not work for others. Overall ant and beetle diversity can remain high in shaded agroforests but the conservation of forest ants and beetles in particular depends primarily on the protection of natural forests, which for forest ants can be complemented by the conservation of adjacent shaded cacao agroforests.     

Avian diversity in a Kenyan agroecosystem: effects of habitat structure and proximity to forest

Tropical agroecosystems cover an increasingly large proportion of the Earth’s terrestrial surface. Yet, relatively little is known about the factors that influence their avifauna, especially in areas of high human population density. The potential of tropical farmland for sustaining bird biodiversity, including forest birds, can be influenced by habitat structure and the distance from the nearest forest. We investigated the effect of these two factors on the bird community in the farmland near Kakamega Forest, Kenya. Using point counts, we assessed the number of bird species and individuals on 56 study plots in distances up to about 2,100 m from the forest. We observed a total of 96 bird species in the farmland, 22 of which were forest, 58 shrub-land, and 16 open-country species. High vertical vegetation heterogeneity and a large number of woody plant individuals were related to high species richness of forest and shrub-land birds, whereas open-country birds avoided such areas. The species richness and total number of forest birds declined with increasing distance to the forest. A comparison with the bird community within Kakamega Forest indicated that only a fraction of the forest species could be sustained in the farmland. This suggests that agroecosystems with a diverse habitat structure can support a high diversity of birds, but have only a limited capacity to compensate for forest loss. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.