Historical Legacies in World Amphibian Diversity Revealed by the Turnover and Nestedness Components of Beta Diversity

Contemporary climate and deglaciation history have received strong support as drivers of species richness and composition for several European taxa. We explored the influence of these factors on patterns of species richness and faunal composition of 244 freshwater gastropod species from 898 European lakes. We evaluated the influence of late Pleistocene deglaciation and seven physiographical and climatic factors on gastropod distributions using multiple linear regression models. We investigated species beta diversity patterns and the influence of species dispersal abilities and/or environment on species composition between lake subsets with different deglaciation history. Contemporary factors and deglaciation history explain parts of variation in species richness across European lakes. Beta diversity analysis revealed moderate to high differences in species composition between the predefined groups. Patterns of species replacement and species loss indicate that lacustrine gastropod faunas of formerly glaciated areas are subsets of non-glaciated ones. Dispersal limitations and environmental gradients control patterns of beta diversity within different lake subsets. We find strong support that the distribution of European limnic gastropods, at least partially, carries the imprint of the last Ice Age. The differences in species richness and composition point towards a gradual, ongoing process of species recolonization after deglaciation.

In this study, through a rapid assessment, we evaluated differences in richness, abundance, species composition and beta diversity of Euglossini bees in preserved areas and areas altered by riverine human populations in the Caxiuanã National Forest (northern Amazon). Our hypotheses were: i) the species richness, diversity, abundance and composition of Euglossini bees differ between the preserved and altered areas because many species are intolerant to small anthropic disturbances; and ii) areas altered by riverine populations have higher values of beta diversity (species dissimilarity between sites) than preserved areas, due to local changes in habitat and increased heterogeneity between sites. We sampled two areas (preserved and altered) and, in each area, four transects were sampled with odorous baits. We used a Student’s t test to evaluate differences in richness, abundance, and Shannon-Wiener diversity index. We also evaluated differences in composition and differences in beta diversity between areas. We collected 102 specimens, identified in 18 species and three genera, 63 individuals (61.8% of the total) in preserved areas and 39 individuals (38.2%) in altered areas. Euglossa liopoda (Dressler, 1982) was the most abundant in altered areas and Euglossa imperialis (Cockerell, 1922) the most abundant in preserved areas. Species richness was 2.5 times greater in the transects of preserved areas, and species composition also differed between the sampled areas. In contrast, species abundance did not differ between transects of both areas. Despite our small sample size, this study demonstrated that the richness, composition and beta diversity of Euglossini bees can be potentially affected by local changes in habitat caused by small-scale activities provided by traditional Amazonian groups. Our results indicate the urgency for more comprehensive studies aimed to investigate these relationships.

Beta diversity describes the differences in species composition among communities. Changes in beta diversity over time are thought to be due to selection based on species' niche characteristics. For example, theory predicts that selection that favors habitat specialists will increase beta diversity. In practice, ecologists struggle to predict how beta diversity changes. To remedy this problem, we propose a novel solution that formally measures selection's effects on beta diversity. Using the Price equation, we show how change in beta diversity over time can be partitioned into fundamental mechanisms including selection among species, variable selection among communities, drift, and immigration. A key finding of our approach is that a species' short-term impact on beta diversity cannot be predicted using information on its long-term environmental requirements (i.e., its niche). We illustrate how our approach can be used to partition causes of diversity change in a montane tropical forest before and after an intense hurricane. Previous work in this system highlighted the resistance of habitat specialists and the recruitment of light-demanding species but was unable to quantify the importance of these effects on beta diversity. Using our approach, we show that changes in beta diversity were consistent with ecological drift. We use these results to highlight the opportunities presented by a synthesis of beta diversity and formal models of selection.

4* 1 (西南林业大学环境科学与工程学院, 昆明 650224) 2 (云南玉溪森林生态系统国家定位观测研究站, 云南玉溪 653400) 3 (北京大学深圳研究生院城市规划与设计学院, 广东深圳 518055) 4 (北京大学城市与环境学院生态学系, 地表过程分析与模拟教育部重点实验室, 北京 100871) 摘要: beta多样性反映了群落间物种组成的差异, 是生物多样性研究的热点之一。本研究通过对云南元江干热河谷 41个植物群落样方进行调查, 用Jaccard相异系数表征物种beta多样性, 用样方之间的最近谱系距离(mean nearest taxon distance, MNTD)及平均谱系距离(mean pairwise distance, MPD)表征谱系beta多样性, 采用基于距离矩阵的多 元回归和方差分解方法, 探讨了该区域干热河谷典型植物群落的物种beta多样性和谱系beta多样性与样方间环境 差异(主要是气候)及地理距离之间的关系。结果表明: (1)群落间的地理距离和年平均温度差异对干热河谷植物群 落的物种beta多样性和谱系beta多样性有显著影响; (2)地理距离对物种beta多样性和MNTD的影响最大; 地理距离 和年平均温度差异对MPD的影响均较大; (3)样方间年平均温度与年平均降水量的差异和地理距离能够解释群落

The helminth community of Lithobates spectabilis (n =77) was studied from Las Pilas (low altitude) and Metznoxtla (high altitude), Biosphere Reserve Barranca de Metztitlán, Hidalgo, Mexico. Species diversity was compared at the infracommunity and the component community level using Hill numbers, and the beta diversity was calculated. Five species of Digenea, 5 of Nematoda, and 2 of Acanthocephala were found in the frogs from the 2 localities. The species richness of parasites in Las Pilas (9 species) was higher than that of Metznoxtla (7 species). The helminth community in Las Pilas was dominated by nematodes and, in Metznoxtla, it was dominated by digeneans. The most prevalent species in Las Pilas was Foleyellides cf. flexicauda (65% of frogs were infected) and, in Metznoxtla, it was Megalodiscus americanus (76% were infected). Glypthelmins quieta was the species with the highest mean abundance in both localities (Las Pilas = 4.5; Metznoxtla = 11.0). The difference in species composition between the 2 localities was significant (Anosim; R = 0.54, p < 0.05). The differences in the composition of species of helminths between the 2 localities suggest that local environmental conditions are different, which may reflect differences in local host diet.

QuestionsAs changing wildfire regimes modify North American deserts, can fires of greater severity and frequency negatively impact the recovery of native bryophyte communities, which are not adapted to such disturbances? Does post‐fire recovery result from the survival of existing surface plants, dormant propagules in sub‐surface soil banks (dispersal in time) or aerial immigration into burned sites (dispersal in space)? Do wildfires negatively affect the survival of propagules in bryophyte soil banks?LocationContinental arid shrublands, Mojave Desert, southwestern US.MethodsWe characterized bryophyte communities along a post‐fire chronosequence spanning three decades across sites where fires had different severities, ages and potential fuels. Three community profiles (surface, soil and aerial) were surveyed with a combination of on‐site surveys and emergence germination techniques. We tested for differences in beta diversity, species composition and richness with PERMDISP, PERMANOVA and linear mixed models, respectively.ResultsBurn severity was associated with differences in beta diversity, species composition and richness, while burn age was associated only with different composition and richness. No effect of potential fuel availability was found. More variation in composition was explained by significant differences among profiles than by other fire attributes. Species richness (but not beta diversity) was higher in soil profiles than in aerial spore rain or existing surface communities. Soils from the oldest and least severe burns had a greater number of species than soils from recent and more severe burns.ConclusionsBryophyte soil banks are common elements of desert soils that facilitate post‐disturbance recovery of communities, but soil banks are themselves threatened by the intensifying frequency and severity of wildfires in North American deserts. Recovery of desert bryophyte communities seems to begin (but not necessarily conclude) within 30 yr after wildfires. In the near future, communities may become perturbed from historical patterns as contemporary fire regimes undergo extensive changes.

Alpha, beta and gamma are three components of species diversity. Knowing these attributes in floodplain lake phytoplankton communities is vital when selecting conservation areas. Species diversity is commonly used with other taxonomic groups, but rarely with phytoplankton. We compared the number of phytoplankton species (alpha diversity) from 21 Middle Araguaia River floodplain lakes in the 2000 and 2001 rainy and dry seasons. From these samples we estimated complete survey species richness (gamma diversity), quantified differences in species composition between lakes (beta diversity) and assessed the influence of abiotic variables on beta diversity. We recorded a total of 577 taxa. The Sjack1 estimator indicated that 62.31% of taxa were sampled in the 2000 rainy and 67.65% dry seasons, and 68.36% in the 2001 rainy and 73.5% dry seasons. In almost all seasons, alpha diversity negatively correlated with latitude. Beta diversity (β-1) was higher in high water periods, especially in 2000. This may have been caused by isolated heavy rainfall, which would have increased environmental heterogeneity and raised beta diversity. DCA showed differences in phytoplankton composition between rainy and dry seasons in 2000 and 2001, reflecting the influence of flood pulses on phytoplankton composition. The Mantel test indicated spatial distribution patterns where geographically more distant lakes had less-similar phytoplankton communities.

Inundation and fire can affect the structure of riparian vegetation in wetlands. Our aim was to verify if there are differences in richness, abundance, basal area, composition and topographic preference of woody species in riparian forests related to the fire history, flooding duration, or the interaction between both. The study was conducted in the riparian forests of the Paraguay River some of which were burned three times between 2001 and 2011. We sampled trees with a girth of at least 5 cm at breast height in 150 5 × 10 m plots (79 burned and 71 unburned). We also measured height of the flood mark and estimated the flooding duration of each plot. We performed Generalized Linear Mixed Models to verify differences in richness, basal area, and abundance of individuals associated to interaction of fire and inundation. We used an analysis of similarity (ANOSIM) and indicator species analysis to identify differences in composition of species and the association with burned and unburned area according to different levels of inundation. Finally, we used a hierarchical set of Generalized Linear Models (GLM), the so-called HOF models, to analyse each species’ specific response to inundation based on topography and to determine their preferred optimal topographic position for both burned as well as unburned areas. Richness was positively associated with elevation only in burned areas while abundance was negatively influenced by inundation only in burned areas. Basal area was negatively associated with time of inundation independent of fire history. There were 15 species which were significant indicators for at least one combination of the studied factors. We found nine species in burned areas and 15 in unburned areas, with response curves in HOF models along the inundation gradient. From these, five species shifted their optimal position along the inundation gradient in burned areas. The interaction of fire and inundation did not appear to affect the basal area, but it did affect the richness, number of individuals, success of some species, and seemed to shape the boundary of these forests as shown by the difference in the positioning of these species along the inundation gradient.

Biological traits related to the adherence strategy of periphytic algae determine species’ dispersal ability and the degree of protection against physical disturbance, such as strong currents and flood pulse. To help understand how water level can structure species with distinct adherence strategy in a floodplain, we investigated periphytic algal beta diversity in subtropical floodplain lakes (upper Parana river floodplain) and evaluate the importance of environmental and spatial drivers in groups with limited dispersal and with higher dispersal abilities. The beta diversity was analyzed considering both presence–absence and species density. We used variance partitioning to evaluate the importance of environmental and spatial processes on periphytic algae. Our results registered 181 species, and the class Bacillariophyceae presented the highest species richness and density. Beta diversity did not differ between months with distinct water levels but differed among lakes. Set of species with higher dispersal abilities presented higher values of beta diversity. Environmental variables were the main driver of periphytic algae composition and density, but spatial variables also drive a significant amount of differences in species composition and density. Beta diversity of species with limited dispersal abilities was mainly driven by environmental factors, and no driver was important to species with higher dispersal. The results of beta diversity indicated that nearest lakes may be more environmentally similar that allows the same species to survive, and also allows species to disperse better among them. These results highlight that the inclusion of functional aspects can clarify the understanding of beta diversity patterns.

Unraveling the processes that drive diversity patterns remains a central challenge for ecology, and an increased understanding is especially urgent to address and mitigate escalating diversity loss. Studies have primarily focused on singular taxonomic groups, but recent research has begun evaluating spatial diversity patterns across multiple taxonomic groups and suggests taxa may have congruence in their diversity patterns. Here, we use surveys of the coral reef benthic groups: scleractinian corals, macroalgae, sponges and gorgonians conducted in the Bahamian Archipelago across 27 sites to determine if there is congruence between taxonomic groups in their site-level diversity patterns (i.e. alpha diversity: number of species, and beta diversity: differences in species composition) while accounting for environmental predictors (i.e. depth, wave exposure, market gravity (i.e. human population size and distance to market), primary productivity, and grazing). Overall, we found that the beta diversities of these benthic groups were significant predictors of each other. The most consistent relationships existed with algae and coral, as their beta diversity was a significant predictor of every other taxa's beta diversity, potentially due to their strong biotic interactions and dominance on the reef. Conversely, we found no congruence patterns in the alpha diversity of the taxa. Market gravity and exposure showed the most prevalent correlation with both alpha and beta diversity for the taxa. Overall, our results suggest that coral reef benthic taxa can have spatial congruence in species composition, but not number of species, and that future research on biodiversity trends should consider that taxa may have non-independent patterns.

Beta diversity, or the turnover in species composition among sampling sites in a region, is an important criterion for obtaining adequate representation of regional biodiversity in systems of protected areas. Recently, the additive model for partitioning regional (gamma) diversity (in opposition to the multiplicative model) has been proposed because it allows a direct measure of the contribution of beta diversity to gamma diversity. We determined avian beta diversity along latitudinal (among neighboring river drainages) and elevational axes in a 1347-km2 region on the western slope of the Central Cordillera of the Colombian Andes, where a regional system of protected areas is being designed. We then compared avian beta diversity between sites based on rapid versus long-term (>1 year) inventories and between fragmented sites versus continuous forest. Overall, beta diversity represented 63.1% of gamma diversity among 16 sites. Elevational differences in species composition accounted for 43.3% of regional diversity, whereas differences among drainages accounted for 19.8%. A complementary cluster analysis showed that sites grouped by elevational zones. Rapid inventories overestimated beta diversity because of sampling effects, but the effect was biologically small. Estimators of species richness derived from species accumulation curves provided a useful alternative to compensate for undersampling in short-term surveys. Forest fragmentation increased beta diversity because of differential local extinction of populations. Nevertheless, in our region, forest fragments contributed to gamma diversity because they contained complementary sets of species. More importantly, they contained populations of special-interest species. Although the region is relatively small, our analyses indicate that spatial differentiation of the biota is an important factor for deciding number and location of protected areas in the Andean region.

Community assembly of island plants is a central topic in island biogeography. Most previous studies have focused on seed plants, while our understanding of bryophytes is limited. Specifically, how dispersal limitation and habitat heterogeneity shape beta diversity of bryophyte communities on islands remains unknown. We used two datasets of bryophyte communities from an artificial (~60 yr of isolation) and natural archipelago (~8500 yr of isolation) to understand their beta diversity patterns. The null model, in which species could disperse randomly and colonize successfully between islands, but the number of species on each island and the frequency of each species occurrence across all islands remain unchanged, was used to calculate expected beta diversity. Although we found significant differences in species composition between the two archipelagos, the difference in observed beta diversity was negligible. Further, there was no significant difference between observed and expected beta diversity in each archipelago. The difference in island area, rather than isolation, was significantly correlated with the beta diversity of bryophytes in both archipelagos. Our results suggest that the dispersal limitation is not the major ecological process driving the assembly of bryophyte communities in both archipelagos, but the habitat heterogeneity related to island area determines the beta diversity of bryophytes.

Subtropical suburban secondary evergreen broadleaved forests are essential in regulating the ecological environment's quality and promoting urban sustainable development. In the suburbs of Hangzhou City, well-preserved secondary evergreen broadleaved forest communities were selected to establish a 6 ha forest dynamic monitoring plot. Community surveys and environmental factor measurements were conducted in this area. This study investigated the beta diversity patterns at different scales by considering the environmental and spatial factors to explore the driving beta diversity. Using a similar paired-site beta diversity decomposition method, the study aimed to investigate the differences in species composition and the mechanisms of multiple species coexistence within the secondary evergreen broadleaved forest communities. The results showed that the beta diversity of the suburban secondary evergreen broadleaved forest communities decreased with the increasing spatial scale. Both the dispersal limitation and the environmental filtering were found to drive the formation of beta diversity patterns in these subtropical suburban forests. At relatively smaller scales (<100 m), species turnover was found to determine the beta diversity patterns of the suburban secondary evergreen broadleaved forests. Dispersal limitation had a dominant influence at more minor scales, while the effect of environmental filtering gradually increased with scale, and the impact of the dispersal limitation decreased. The partitioning of the beta diversity in subtropical secondary evergreen broadleaved forests in China provides critical scientific insights into the spatial distribution patterns and changes in biodiversity. It offers valuable knowledge for the conservation and understanding of biodiversity maintenance in the region.

Both deterministic and stochastic processes have been linked to forest community assembly; however, their contribution to beta diversity has not been properly explored, and no studies to date have investigated their impacts on sparse depleted soils in forests that contain widespread exposed limestone karst. We found that the pairwise differences in species composition between quadrates was determined by a balanced variation in abundance, whereby the individuals of some species at one site were substituted by an equivalent number of individuals of different species at another site. Both the total beta diversity and its balanced variation in abundance declined with increasing sampling grain size. Our research indicated that environmental differences exert a strong influence on beta diversity, particularly total beta diversity and its balanced abundance variation in larger grain sizes. It was evident that deterministic and stochastic processes worked together, and that deterministic processes were more important than stochastic processes in the regulation of beta diversity in this heterogeneous tropical karst seasonal rainforest of Southern China. However, in future research a functional trait based approach will be required to tease out the relative degree of deterministic and stochastic processes toward an assessment of the temporal changes in species composition.

Aim Urbanization is associated with strong changes in biodiversity, but the diversity of plant and animal assemblages varies among urban habitats. We studied effects of urban habitats on the diversity of vascular plants and land snails in 32 large cities. Location Central Europe, Belgium and the Netherlands. Methods The species composition of all vascular plants that had not been planted by humans, and all land snails, was recorded in seven 1-ha plots within each city. Each plot contained one urban habitat type representing a different disturbance regime: historical city square, boulevard, residential area with compact building pattern, residential area with open building pattern, park, early successional and mid-successional site. For each plot, we obtained temperature and precipitation data. The effects of climate and habitat types on species composition were quantified using ordination methods with an adjusted variation partitioning algorithm. Differences in species composition among urban habitats were described using statistically determined diagnostic species, and differences in alpha, beta and gamma diversity were quantified. Results A total of 1196 plant and 87 snail species were recorded. Habitat type explained higher proportions of the total variation in both plant and snail species composition (11.2 and 8.2%, respectively) than did climate (4.6 and 6.3%). For both taxa, the main differences in species composition were observed between strongly urbanized sites in city centres and early successional and mid-successional sites. For vascular plants, the number of species was lowest in city squares and boulevards, and highest at successional sites and in residential areas with compact building patterns. Beta diversity of vascular plants calculated for the same habitat types among cities was highest for squares and successional sites. The number of snail species was lowest in city squares and at early successional sites, and highest at mid-successional sites. The highest beta diversity of snail assemblages among cities was observed within the city square and early successional habitat types, and the lowest within residential area habitat types. Main conclusions Urban habitats differ notably in the diversity of their vascular plant flora and land snail fauna. Understanding the habitat-related biodiversity patterns in urbanized landscapes will allow projections of future impacts of urban land-use changes on the biota.