镉胁迫对2种油菜土壤真菌群落的影响

[背景] 人类活动引起的农田重金属污染已成为严重的环境问题。镉（Cd）是最具毒性的重金属之一,能对人体和生态系统构成威胁。[目的] 研究不同浓度镉处理对2种油菜（甘蓝型油菜和芥菜型油菜）的土壤（根际和非根际）真菌群落的影响,为镉的生物修复和健康风险评估提供理论基础。[方法] 对2种油菜土壤（根际和非根际）真菌转录间隔区（Internal Transcribed Spacer,ITS）进行高通量测序,分析镉对根际和非根际土壤真菌群落的影响。[结果] 镉胁迫改变了土壤真菌群落的组成和结构,但对2种油菜土壤真菌群落的α多样性几乎无显著影响。土壤镉浓度和生物量与2种油菜根际土壤真菌群落显著相关,芥菜型油菜非根际土壤真菌群落也与镉污染浓度显著相关。土壤真菌分子生态网络也受到镉污染的影响,甘蓝型油菜根际土壤网络稳定性降低,共生关系减少。甘蓝型油菜非根际土壤网络稳定性升高,但共生关系减少。芥菜型油菜的根际和非根际土壤的网络稳定性升高,而且共生关系增多。[结论] 镉污染会影响土壤系统中的本土真菌群落,从而可能进一步改变土壤的生态系统功能。     

柴达木盆地尕斯库勒盐湖区邻近水体对湖泊微生物群落的贡献

【目的】探究尕斯库勒盐湖生态系统中邻近水体对湖泊微生物的贡献。【方法】采集尕斯库勒盐湖区湖水、沉积物以及邻近的泉水、河水和盐田的水样,对其进行地球化学分析;通过16S rRNA基因的Illumina MiSeq高通量测序分析样品的微生物群落组成。【结果】尕斯库勒盐湖区水体和沉积物中的优势门是变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、放线菌门(Actinobacteria)和广古菌门(Euryarchaeota)。盐度和pH是影响尕斯库勒盐湖区群落组成的最主要环境因素。邻近水体对湖泊水体和沉积物的贡献分别为12.94%和7.53%。【结论】邻近水体对尕斯库勒盐湖微生物群落的贡献有限。     

Habitat associations and breeding bird community composition within the city of Bristol,UK

Capsule Different urban breeding bird communities are associated with different habitat types, but, although community species diversity varies significantly, total bird density does not.

Aims To investigate the association between breeding bird communities and habitats within Bristol, UK and how these communities vary in terms of species diversity and total bird abundance.

Methods Breeding density data for 70 species in the metropolitan area of Bristol, UK were subjected to de‐trended correspondence analysis to identify the number of different communities present and their indicator species. These data were then used to identify patterns of habitat association with each community and differences in species richness and total bird density.

Results Three communities were identified: a rural community associated with woodland, managed grassland and inland water; a suburban community associated with buildings and residential gardens; and an intermediate community that shared some of these habitat characteristics. Species richness, but not total bird abundance, was lowest in the suburban community.

Conclusion The diversity of species in urban areas appears to be most dependent upon the availability of patches of natural and semi‐natural habitats. Residential gardens support fewer species, but those species that are present may be found at high densities.     

Report of the Annual Conference of the Cryptogamic Section, 1948

Background: Trait-based assembly rules are a powerful tool in community ecology, used to explore the pattern and process of community structure (richness and composition).

Aims: A preliminary test for the utility of trait-based assembly rules in explaining cryptogamic epiphyte communities (lichens and bryophytes).

Methods: We sampled epiphytes from three different tree species (aspen, birch and pine), and from trees of contrasting age. The community composition of epiphyte species (taxon analysis) and functional groups (trait analysis) was summarised using multivariate ordination (nonmetric multidimensional scaling, NMDS).

Results: Ordination documented a widely observed pattern in which different tree species have taxonomically different epiphyte communities. However, NMDS sample scores were correlated to tree age in the trait-based analysis, but not in the taxon analysis.

Conclusions: Our results point to the existence of a common pattern in community traits during succession (on trees of different age) when measured for epiphyte communities with contrasting taxonomic composition. This pattern is evidenced by consistent trends in lichen growth form and reproductive strategy (sexual vs. asexual).     

Patterns of phylogenetic community structure of sand dune plant communities in the Yucatan Peninsula: the role of deterministic and stochastic processes in community assembly

ABSTRACT

Background: Tropical sand dunes are ideal systems for understanding drivers of community assembly as dunes are subject to both deterministic and stochastic processes. However, studies that evaluate the factors that mediate plant community assembly in these ecosystems are few.

Aims: We evaluated phylogenetic community structure to elucidate the role of deterministic and stochastic processes in mediating the assembly of plant communities along the north of the Yucatan Peninsula, Mexico.

Methods: We used plastid genetic markers to evaluate phylogenetic relationships in 16 sand-dune communities. To evaluate the role of climate in shaping plant community structure we carried out linear regressions between climatic variables and mean phylogenetic distance. We estimated the Net Relatedness Index and Nearest Taxon Index to identify ecological processes mediating community assembly.

Results: Observed phylogenetic structure was not different from random, suggesting that stochastic processes are the major determinants of community assembly. Climate was slightly correlated with phylogenetic diversity suggesting that abiotic environment plays a minimal role in community assembly.

Conclusions: Random assembly appears to be the primary factor structuring the studied sand dune plant communities. Environmental filters may represent a secondary factor contributing to the observed phylogenetic structure. Thus, both processes may act simultaneously to mediate the assembly of sand-dune plant communities.     

On the species-pool hypothesis and on the quasi-neutral concept of plant community diversity

5.1. According to the results from studying a broad variety of Estonian herbaceous communities (4.11) the question in 1.14 should be answered as:selection from a regional species pool into an actual species pool and selection from actual species pool into a microsite are mostly random and neutral processes and they are not directed significantly by interspecific competition. 5.2. Yet, the formation of a diversity pattern should be called aquasi-neutral process,mainly because the exclusion of species from communities due to asymmetric light competition is common during succession (when taller species outcompete shorter ones).     

Microbiology research at the systems biology and bioinformatics - 2019 (SBB-2019) school

Background

The Uzon Caldera is one of the places on our planet with unique geological, ecological, and microbiological characteristics. Uzon oil is the youngest on Earth. Uzon oil has unique composition, with low proportion of heavy fractions and relatively high content of saturated hydrocarbons. Microbial communities of the «oil site» have a diverse composition and live at high temperatures (up to 97 °C), significant oscillations of Eh and pH, and high content of sulfur, sulfides, arsenic, antimony, and mercury in water and rocks.

Results

The study analyzed the composition, structure and unique genetics characteristics of the microbial communities of the oil site, analyzed the metabolic pathways in the communities. Metabolic pathways of hydrocarbon degradation by microorganisms have been found. The study found statistically significant relationships between geochemical parameters, taxonomic composition and the completeness of metabolic pathways. It was demonstrated that geochemical parameters determine the structure and metabolic potential of microbial communities.

Conclusions

There were statistically significant relationships between geochemical parameters, taxonomic composition, and the completeness of metabolic pathways. It was demonstrated that geochemical parameters define the structure and metabolic potential of microbial communities. Metabolic pathways of hydrocarbon oxidation was found to prevail in the studied communities, which corroborates the hypothesis on abiogenic synthesis of Uzon hydrothermal petroleum.

     

Evaluating the diagnostic test accuracy of molecular xenomonitoring methods for characterising the community burden of Onchocerciasis

BackgroundMolecular xenomonitoring (MX), the detection of parasite nucleic acid in the vector population, is recommended for onchocerciasis surveillance in elimination settings. However, the sensitivity of MX for detecting onchocerciasis-positive communities has not previously been evaluated. MX may have additional applications for control programmes but its utility is restricted by a limited understanding of the relationship between MX results and human prevalence.MethodsWe conducted a systematic review of studies reporting the prevalence of Onchocerca volvulus DNA in wild-caught Simulium spp. flies (MX rate) and corresponding prevalence of microfilaria (mf) in humans. We evaluated the sensitivity of MX for detecting onchocerciasis-positive communities and describe the characteristics of studies with reduced sensitivity. We conducted a linear regression to evaluate the relationship between mf prevalence and MX rate.ResultsWe identified 15 relevant studies, with 13 studies comprising 34 study communities included in the quantitative analyses. Most communities were at advanced stages towards elimination and had no or extremely low human prevalence. MX detected positive flies in every study area with >1% mf prevalence, with the exception of one study conducted in the Venezuelan Amazonian focus. We identified a significant relationship between the two measurements, with mf prevalence accounting for half of the variation in MX rate (R² 0.50, p<0.001).ConclusionMX is sensitive to communities with ongoing onchocerciasis transmission. It has potential to predict human mf prevalence, but further data is required to understand this relationship, particularly from MX surveys conducted earlier in control programmes before transmission has been interrupted.     

Vegetation,microclimate and soils associated with the latest-lying snowpatches in Australia

Background : The Snowy Mountains contain Australia's longest-lasting snowpatches. Because of climate change, their longevity has declined, with the loss of some specialist vegetation in the underlying snowbeds.

Aims: To characterise the current status of the vegetation associated with the longest-lasting snowpatches in Australia and its association with abiotic factors.

Methods: We assessed plant composition, soil depth, moisture and nutrients and subsurface temperatures in five zones of increasing vegetation height and cover in snowbeds.

Results: The zone beneath the middle of snowpatches was characterised by little vegetation cover and lower species richness, later emergence from snow, skeletal soils, and lower mean soil temperatures than zones further downslope where soils increased in depth and nutrient levels. Vegetation beneath these snowpatches no longer occurs in distinct communities. Plants have not simply migrated upslope, instead, areas that have deep soil that used to have snowpatch specialist species are being colonised upslope by grasses and downslope by tall alpine herbfield species that prefer bare ground.

Conclusions: Reduced longevity of Australia's longest-lasting snowpatches has led to the loss of distinct snowpatch plant communities. With limited soils beneath the centre of current snowpatches, and a lack of other suitable sites there is no location for these plant communities to migrate to.     

The role of environmental factors for the composition of microbial communities of saline lakes in the Novosibirsk region (Russia)

Background

Nothing is currently known about microbial composition of saline lakes of the Novosibirsk region and its dependence on physical-chemical parameters of waters. We studied the structure of microbial communities of saline lakes of the Novosibirsk region and the effect of physical-chemical parameters of waters on microbial communities of these lakes.

Results

According to the ion content, the lakes were classified either as chloride or chloride-sulfate types. Water salinity ranges from 4.3 to 290 g L⁻¹. Many diverse microbial communities were found. Filamentous and colonial Cyanobacteria of the genera Scytonema, Aphanocapsa, and/or filamentous Algae dominated in littoral communities. Spatial and temporal organization of planktonic microbial communities and the quantities of Archaea and Bacteria were investigated using fluorescent in situ hybridization. We have found that the dominant planktonic component is represented by Archaea, or, less frequently, by Bacteria. Various phylogenetic groups (Bacteria, Archaea, Algae, and Cyanobacteria) are nonuniformly distributed. The principal component analysis was used to detect environmental factors that affect microorganism abundance. We found the principal components responsible for 71.1 % of the observed variation. It was demonstrated that two-block partial least squares was a better method than principal component analysis for analysis of the data. We observed general relationships between microbial abundance and water salinity.

Conclusions

We have performed the first-ever study of the structure of the microbial communities of eleven saline lakes in the Novosibirsk region along with their physical-chemical parameters of waters. Our study demonstrates that saline lakes in the Novosibirsk region contain a unique microbial communities that may become a prolific source of microorganisms for fundamental and applied studies in various fields of ecology, microbiology, geochemistry, and biotechnology, and deserve further metagenomic investigation.

     

凡纳滨对虾生物絮团养殖系统中不同生境细菌群落特征

【目的】凡纳滨对虾生物絮团养殖系统(biofloc-based culture system, BFS)是一种基于培育和调控微生物群落的新型生态养殖模式。然而,目前对于BFS在不同生境中的微生物群落特征及其构建过程还不清楚。【方法】采用16S rRNA基因测序技术探究BFS在3种不同生境(水体、絮团和对虾肠道)的细菌群落组成;通过溯源分析和中性模型等方法,探究不同生境细菌群落的特征及其构建过程。【结果】3种生境的微生物群落多样性和组成具有显著性差异,絮团和对虾肠道的群落结构和组成最为相似,溯源结果显示对虾肠道有98.76%的细菌类群来自絮团,仅有0.83%的细菌类群来自水体;3种生境共有的细菌主要为鲁杰氏菌(Ruegeria),在水体、絮团和对虾肠道中的丰度分别为1.72%、7.34%和6.00%,水体中特有的扩增子变异序列(amplicon sequence variants, ASV)数量为89个,主要属于海茎状菌(Maricaulis)和欧文威克斯菌(Owenweeksia),絮团中有56个,主要为莱茵海默氏菌(Rheinheimera),而对虾肠道中仅有10个,主要属于玫瑰杆菌(Roseobacter);中性模型结果表明,水体、絮团和对虾肠道细菌群落构建均符合中性模型,表明3种生境中细菌群落构建均受中性过程主导。【结论】在BFS系统中,不同生境的微生物群落具有显著差异,对虾肠道细菌主要来自生物絮团,而3种生境的细菌群落构建过程由中性过程主导。这些结果为调控生物絮团养殖系统中微生物群落提供了理论依据。     

The consequences of multiple resource shifts on the productivity and composition of alpine tundra communities: inferences from a long-term snow and nutrient manipulation experiment

Background: Gradients in the amounts and duration of snowpack and resulting soil moisture gradients have been associated with different plant communities across alpine landscapes.

Aims: The extent to which snow additions could alter plant community structure, both alone and in combination with nitrogen (N) and phosphorus (P) additions, provided an empirical assessment of the strength of these variables on structuring the plant communities of the alpine tundra at Niwot Ridge, Colorado Front Range.

Methods: A long-term snow fence was used to study vegetation changes in responses to snowpack, both alone and in conjunction with nutrient amendments, in plots established in dry and moist meadow communities in the alpine belt. Species richness, diversity, evenness and dissimilarity were evaluated after 20 years of treatments.

Results: Snow additions, alone, reduced species richness and altered species composition in dry meadow plots, but not in moist meadow; more plant species were found in the snow-impacted areas than in nearby controls. Changes in plant community structure to N and N + P additions were influenced by snow additions. Above-ground plant productivity in plots not naturally affected by snow accumulation was not increased, and the positive responses of plant species to nutrient additions were reduced by snow addition. Plant species showed individualistic responses to changes in snow and nutrients, and indirect evidence suggested that competitive interactions mediated responses. A Permanova analysis demonstrated that community dissimilarity was affected by snow, N, and P additions, but with these responses differing by community type for snow and N. Snow influenced community patterns generated by N, and finally, the communities impacted by N + P were significantly different than those affected by the individual nutrients.

Conclusions: These results show that changes in snow cover over a 20-year interval produce measureable changes in community composition that concurrently influence and are influenced by soil nutrient availability. Dry meadow communities exhibit more sensitivity to increases in snow cover whereas moist meadow communities appear more sensitive to N enrichment. This study shows that the dynamics of multiple limiting resources influence both the productivity and composition of alpine plant communities, with, species, life form, and functional traits mediating these responses.     

海草根际微生物与海草植株的互作效应

【目的】本文以三亚湾泰来草根际沉积物为主要研究对象,研究室内培养条件下泰来草根际沉积物微生物对于高温处理和海草定殖的响应。【方法】通过对培养过程中水体物理化学参数(如pH、溶解氧、磷酸盐、硝酸盐、亚硝酸盐和铵盐)的监测以分析环境因子的变化;16S rRNA扩增子测序研究微生物群落结构的动态响应;通过荧光定量分析16SrRNA基因丰度变化。【结果】研究表明高温处理组在培养35 d后海水中磷酸盐、硝酸盐、亚硝酸盐和铵盐含量以及pH均要高于模拟原位环境的对照组,高温处理组根际沉积物微生物丰度在培养过程中呈现先上升后降低的趋势,同时,高温处理组根际微生物中初始阶段由厚壁菌门(32.4%)、变形菌门(22.92%)和梭杆菌门(27.21%)占据优势,培养一段时间后,厚壁菌门和梭杆菌门大幅度减少,逐渐被蓝细菌门和放线菌门所替代,最终由变形菌门(51.1%)占据主导地位,其中,属于硫还原细菌的脱硫杆菌科(Desulfobacteraceae)和硫氧化细菌的螺杆菌科(Helicobacteraceae)的细菌丰度不断提高。【结论】揭示了海草的定殖会提高高温处理后沉积物的多样性,并塑造和改善其根际沉积物微生物群落组成。     

Soil pH is the primary factor driving the distribution and function of microorganisms in farmland soils in northeastern China

Purpose

To understand which environmental factors influence the distribution and ecological functions of bacteria in agricultural soil.

Method

A broad range of farmland soils was sampled from 206 locations in Jilin province, China. We used 16S rRNA gene-based Illumina HiSeq sequencing to estimated soil bacterial community structure and functions.

Result

The dominant taxa in terms of abundance were found to be, Actinobacteria, Acidobacteria, Gemmatimonadetes, Chloroflexi, and Proteobacteria. Bacterial communities were dominantly affected by soil pH, whereas soil organic carbon did not have a significant influence on bacterial communities. Soil pH was significantly positively correlated with bacterial operational taxonomic unit abundance and soil bacterial α-diversity (P<0.05) spatially rather than with soil nutrients. Bacterial functions were estimated using FAPROTAX, and the relative abundance of anaerobic and aerobic chemoheterotrophs, and nitrifying bacteria was 27.66%, 26.14%, and 6.87%, respectively, of the total bacterial community. Generally, the results indicate that soil pH is more important than nutrients in shaping bacterial communities in agricultural soils, including their ecological functions and biogeographic distribution.

     

~(13)C-标记秸秆添加对DNA稳定性同位素探针试验结果的影响

【目的】稳定性同位素探针技术(stable isotope probing,SIP)是采用稳定性同位素示踪复杂环境中具有代谢活性微生物的有力工具。然而,在近期利用SIP技术的研究当中,我们发现~(13)C-标记物对试验本身有一定程度影响。例如研究土壤秸秆降解微生物,需将~(13)C-标记作物秸秆添加到土壤,利用微域培养实验和DNA-SIP技术解析主导降解微生物物种。但是~(13)C秸秆的添加以及不同土壤肥力水平是否会影响土壤微生物群落有待商榷。【方法】本研究采集江西鹰潭红壤试验站3种施肥处理(Control、NPK、OM)水稻土壤,分别添加自然丰度(12C)和~(13)C-标记的高丰度水稻秸秆,进行微域培养试验,研究两种秸秆添加下的响应物种以及不同丰度C对生物质气体的累积排放、细菌a-多样性以及群落结构的影响。【结果】研究发现,3种施肥土壤下,2种丰度秸秆处理间C累计排放无差异。但是,寡营养条件(Control)下,~(13)C-标记秸秆处理的细菌a-多样性高,12C秸秆处理群落异质性高,稳定性较差,无差异性物种;与~(12)C秸秆处理相比,富营养条件(NPK和OM)下,~(13)C-标记秸秆处理的细菌a-多样性和群落结构无差异,但存在差异物种,主要集中于变形菌门和稀有物种。【结论】本研究的结果表明~(13)C标记秸秆对微生物群落有一定影响,因此在后续的SIP试验中,高丰度秸秆虽可被用来作为标记底物,但需慎用。     

富营养化城市湖泊武汉东湖沉积物微生物群体结构及空间变化研究(英文)北大核心CSCD

【目的】城市湖泊沉积物中的微生物群体是富营养环境生物修复的重要因素。本研究拟对中型富营养化湖泊——武汉东湖沉积物细菌群体结构及空间变化规律进行研究。加深对富营养湖泊微生物群体结构的理解,并为城市湖泊的保护和污染控制提供参考。【方法】采用16S r RNA基因RFLP分析和序列分析技术获得细菌群体系统发育信息。采用PCoA法分析武汉东湖沉积物细菌群体内以及与其它湖泊沉积物细菌群体间的相似性。采用CCA法分析环境因素对细菌群体的影响。【结果】武汉东湖沉积物细菌群体包含13个门和2个未知种群。PCoA分析进一步表明来自东湖3个子湖的细菌群体与其它地域富营养化湖泊的微生物种群结构相似,并区别于重度富营养化子湖庙湖的细菌群体。在庙湖中,我们发现了Thermogymnomonas类古菌的含量显著偏高。CCA分析表明细菌的分布与沉积物中碳、氮和磷元素的含量显著相关。【结论】本研究进一步确证了环境因素对细菌群体组成和分布的调节作用,加深了对富营养水体微生物群体结构的理解,并为城市湖泊的保护和污染控制提供了参考。     

Assessing ectomycorrhizal fungal spore banks of truffle producing soils with pecan seedling trap-plants

Background and Aims

Recently, the truffle species Tuber lyonii Butters was found to be dominant in ectomycorrhizal (EcM) fungal communities of cultivated pecan (Carya illinoinensis (Wangenh.) K. Koch). Many truffle fungi exhibit the trait of effectively colonizing plant roots via spores. We hypothesized that T. lyonii would be well represented in the spore bank of pecan orchard soils where it is found.

Methods

We used axenically-grown pecan seedlings as trap-plants to bait for EcM associates in soils collected beneath truffle-producing pecan trees. EcM fungi on seedlings were characterized through rDNA sequencing and were compared to EcM communities of adult trees in these orchards.

Results

Tuber lyonii mycorrhizas were well formed on seedlings inoculated with truffle spores, but were limited to just a few of the trap-plants grown in field soils. We compared EcM communities of adult pecan orchard trees to those on trap-plants and found distinct communities on each, with a high degree of similarity at the ordinal but not species level.

Conclusions

Although species of Pezizales are abundant in pecan EcM communities and as propagules in their soil spore banks, only a low level of T. lyonii was detected in soil spore banks beneath orchard trees naturally colonized by T. lyonii. Other factors including land-use history or orchard management may better explain this truffle species presence and abundance in pecan EcM communities.

     

Segregation,nestedness and homogenisation in plant communities dominated by native and alien species

ABSTRACT

Background: Highly modified landscapes offer the opportunity to assess how environmental factors influence the integration of alien plant species into native vegetation communities and determine the vulnerability of different communities to invasion.

Aims: To examine the importance of biotic and abiotic drivers in determining whether alien plant species segregate spatially from native plant communities or become integrated and lead to biotic homogenisation.

Methods: Ordination and classification of a floristic survey of over 1200 systematically located 6 m × 6 m plots were used to examine how plant community segregation, nestedness and homogenisation varied in relation to climate, environmental and human-related factors across Banks Peninsula, New Zealand.

Results: The analyses of community structure indicated that native and alien plant communities were spatially and ecologically segregated due to different responses primarily to an anthropogenic impact gradient and secondly to environmental factors along an elevation gradient. Human-land use appeared most strongly linked to the distribution of alien species and was associated with increased vegetation homogenisation. However, despite spatial segregation of alien and native plant communities, biotic homogenisation not only occurred in highly managed grasslands but also in relatively less managed shrublands and forest.

Conclusions: The role played by anthropogenic factors in shaping alien and native plant species community structure should not be ignored and, even along a marked environmental gradient, if the recipient sites have a long history of human-related disturbance, biotic homogenisation is often strong.     

Habitat-islands in the coastal Atacama Desert: loss of functional redundancy,but not of functional diversity,with decreased precipitation

Background and AimsAridity is increasing in many regions of the world, but microclimatic conditions may buffer plant communities from the direct effects of decreased precipitation, creating habitat islands. However, reduced precipitation can also impact these communities indirectly by decreasing the suitability of the surrounding habitat, thus limiting incoming propagules and increasing the chances of population decline and species loss. We test whether decreased precipitation results in loss of species and functional diversity within habitat islands, evaluating in particular whether declines in species diversity and abundance are less likely to result in loss of functional diversity if species/individual loss is stochastic (i.e. independent of species/individual traits) and communities/populations are functionally redundant.MethodsLomas communities are discrete plant communities embedded in the Atacama Desert, maintained by the microclimatic conditions created by fog. We recorded species and functional diversity in six Lomas communities along a 500 km long precipitation gradient in northern Chile. Functional traits were measured in 20 individuals per species, in those species that accounted for approx. 75 % of the abundance at each site. We calculated functional diversity and functional redundancy of the community, and intraspecific functional variation.Key ResultsDecreased precipitation was associated with lower species diversity and lower species abundances. However, no traits or functional strategies increased or decreased consistently with precipitation, suggesting stochastic species/individual loss. Species with stress-tolerant strategies were predominant in all sites. Although species diversity decreased with decreasing precipitation, functional diversity remained unchanged. Lower functional redundancy in the drier sites suggests that mainly functionally redundant species were lost. Likewise, intraspecific functional variation was similar among communities, despite the lower species abundance in drier sites.ConclusionsDecreased precipitation can impact habitat island communities indirectly by decreasing the suitability of the surrounding habitat. Our results support the idea that a stochastic loss of species/individuals from functionally redundant communities and populations does not result in loss of functional diversity.