Climate Dissimilarity Research Articles

Phenotypic plasticity rather than ecotypic differentiation explains the broad realized niche of a Neotropical orchid species.

Local adaptation is common in plant species, and knowing whether a population is locally adapted has fundamental and applied relevance. However, local adaptation in tropical plants remains largely less studied, and covering this gap is not simple since reciprocal transplantation - the gold standard for detecting local adaptation - is not feasible for most species. Here, we combined genetic, climatic and phenotypic data to investigate ecotypic differentiation, an important aspect of local adaptation, in coastal and inland populations of the orchid Epidendrum fulgens Brongn., a long-lived tropical plant for which reciprocal transplantation would not be feasible. We used nine microsatellite markers to estimate genetic divergence between inland and coastal populations. Moreover, occurrence data and climate data were used to test for differences in the realized niche of those populations. Finally, we assessed saturated water content, leaf specific area, height, and stomatal density in common garden and in situ to investigate the effects of ecotypic differentiation and plasticity on the phenotype. Coastal and inland groups' niches do not overlap, the former occupying a wetter and warmer area. However, this differentiation does not seem to be driven by ecotypic differentiation since there was no positive correlation between genetic structure and climate dissimilarity. Moreover, specific leaf area and leaf saturated water content, which are important phenotypic traits related to soil fertility and drought stress, were rather plastic. We conclude that ecotypic differentiation is absent, since phenotypic plasticity is an important mechanism explaining the niche broadness of this species.

Climate influences the genetic structure and niche differentiation among populations of the olive field mouse Abrothrix olivacea (Cricetidae: Abrotrichini)

Even when environmental variation over time and space is commonly considered as an important driver of population divergence, few evaluations of intraspecific genetic variation explicitly assess whether observed structure has been caused by or is correlated with landscape heterogeneity. Several phylogeographic studies have characterized the mitochondrial diversity of Abrothrix olivacea, but none has incorporated landscape genetics analyses and ecological niche modeling, leaving a gap in the understanding of the species evolutionary history. Here, these aspects were addressed based on 186 single nucleotide polymorphisms, extracted from sequences of 801 bp of Cytb gene, gathered from 416 individuals collected at 103 localities in Argentina and Chile. Employing multivariate statistical analyses (gPCA, Mantel and Partial Mantel Tests, Procrustes Analysis, and RDA), associations between genetic differences and geographic and climatic distances were evaluated. Presence data was employed to estimate the potential geographic distribution of this species during historical and contemporary climatic scenarios, and to address differences among the climatic niches of their main mitochondrial lineages. The significant influence of landscape features in structuring mitochondrial variability was evidenced at different spatial scales, as well as the role of past climatic dynamics in driving geographic range shifts, mostly associated to Quaternary glaciations. Overall, these results suggest that throughout geographic range gene flow is unevenly influenced by climatic dissimilarity and the geographic distancing, and that studied lineages do not exhibit distributional signals of climatic niche conservatism. Additionally, genetic differentiation occurred by more complex evolutionary processes than mere disruption of gene flow or drift.

The influence of ecological engineering projects on dust events: A case study in the northern China

Since the late 1970s, many large-scale ecological engineering projects have been implemented to mitigate and remediate hastily degraded ecological condition in northern China. The purpose of this study is to assess the influences of these projects by examining the correlation between natural factors and dust events. First, the spatiotemporal variations in dust events in study area are analyzed, using the dust report data of 270 stations of the synoptic observation from 1978 to 2018. Furthermore, the variations in vegetation and meteorological conditions are evaluated and the correlation between dust events and various natural factors is investigated. The results show that dust events are generally decreased, along with significant improvement in vegetation, especially on the edge of desert areas. Moreover, >75% of dust events occurred before year 2000. Also, spatial distribution of dust events is quite diverse. The area with declining dust events is accordance with the area with increasing NDVI, while the NDVI improving trend in 2000–2018 is more significant than that in 1982–1999. Through hotspot analysis, evaporation and relative humidity are two leading factors with higher relative importance and correlation coefficient in all groups. Nonetheless, owing to substantial geographical difference and climatic dissimilarity, there are noticeable differences among various groups, as RHU is the only factor with highest correlation in all six groups, EVP is the highest correlated factor in G1 and G3, and WIN dominates in G2, G4, G5, and G6. These findings can be important guidelines for dust storm prevention design in ecological engineering projects

Climatic dissimilarity associated with phylogenetic breaks

AbstractShared phylogenetic breaks often are associated with clear geographic barriers but some common phylogeographic breaks may lack obvious underlying mechanisms. A phylogenetic break involving multiple taxa was found in the Baja California Peninsula that was associated with a past sea barrier. However, geological evidence is lacking for this barrier’s past existence, and despite its current absence, the genetic breaks have persisted. This work explores the relationships between the current climatic niches for matrilineages of 11 vertebrate species as a possible explanation for the current geographic partitioning of matrilineages. We evaluated the climatic occupancy of each matrilineage through ecological niche models, background similarity, niche overlap, niche divergence, and Mantel tests. We found disparities in the climatic occupancy between north and south matrilineage of each taxon. Northern matrilineages are associated with lower temperatures and winter rains, while southern matrilineages reside in areas with higher temperatures and summer rains.

Cropland connectivity affects genetic divergence of Colorado potato beetle along an invasion front.

The population genetic structure of invasive species can be strongly affected by environmental and landscape barriers to dispersal. Disentangling the relative contributions of these factors to genetic divergence among invading populations is a fundamental goal of landscape genetics with important implications for invasion management. Here, we relate patterns of genetic divergence in a global invasive agricultural pest, Colorado potato beetle (CPB; Leptinotarsa decemlineata), to environmental and landscape factors along an invasion front in Northwestern China. We first used microsatellite markers and spatial‐temporal samples to assess broad patterns of genetic diversity as well as fine‐scale changes in patterns of genetic divergence. We then distinguished the relative contributions of five factors to genetic divergence among front populations: geographic distance (isolation by distance), climate dissimilarity (isolation by environment), and least‐cost distances (isolation by resistance) modeled with three factors: climate suitability, cropland cover, and road networks. Genetic diversity broadly decreased from West to East, with the exception being Eastern China. Low levels of genetic diversity and varying degrees of divergence were observed in Northwestern China, reflecting the potential effect of landscape heterogeneity. Least‐cost distance across cropland cover was most positively correlated with genetic divergence, suggesting a role of croplands in facilitating gene flow. The contribution of climate to genetic divergence was secondary, whether modeled in terms of local adaptability or connectivity of the climatic landscape, suggesting that constraints to CPB gene flow imposed by a harsh climate may be ameliorated in agricultural landscapes. No evidence was found for an obvious effect of road networks on genetic divergence and population structuring. Our study provides an example of how agricultural landscape connectivity can facilitate the spread of invasive pests, even across a broad climatic gradient. More broadly, our findings can guide decisions about future land management for mitigating further spread.

Human indoor climate preferences approximate specific geographies.

Human engineering of the outdoors led to the development of the indoor niche, including home construction. However, it is unlikely that domicile construction mechanics are under direct selection for humans. Nonetheless, our preferences within indoor environments are, or once were, consequential to our fitness. The research of human homes does not usually consider human evolution, and, therefore, we are without previous predictions about indoor climate preference. We worked with citizen scientists to collect indoor climate data from homes (n = 37) across the USA. We then compared these data to recent global terrestrial climate data (0.5° grid cells, n = 67 420) using a climate dissimilarity index. We also compared some climate-related physiological parameters (e.g. thermoneutral zone (TNZ)) between humans and a selection of non-human primates. On average, our study homes were most similar in climate to the outdoor conditions of west central Kenya. We found that the indoor climates of our study homes largely matched the TNZ of humans and other primates. Overall, we identified the geographical distribution of the global outdoor climate that is most similar to the interiors of our study homes and summarized study home indoor climate preferences.

Birds in the Himalayas: What drives beta diversity patterns along an elevational gradient?

Beta diversity patterns along elevational gradients have become a hot topic in the study of biogeography and can help illuminate the processes structuring mountain ecosystems. Although elevational species richness patterns have been well documented, there remains much uncertainty over the causes of beta diversity patterns across elevational gradients. We conducted bird surveys and obtained high‐resolution climatic data along an elevational gradient in Gyirong Valley in the central Himalayas, China, between 1,800 and 5,400 m elevation. In total, we recorded 182 bird species (including 169 breeding birds). We simulated beta diversity patterns with the mid‐domain effect (MDE) null model and conducted distance‐based redundancy analyses (db‐RDA) to relate beta diversity to dispersal limitations, spatial constraints, habitat complexity, contemporary climate, and historical climate. Mantel tests and variation partitioning were employed to identify the magnitude of independent statistical associations of environmental factors with beta diversity. Patterns of empirical and simulated beta diversity were both hump‐shaped, peaking at intermediate elevations. The db‐RDA indicated that beta diversity was correlated with changes in spatially structured environmental factors, especially with contemporary climate and habitat complexity. Mantel tests and variation partitioning also suggested that climate dissimilarity was the major independent correlate of beta diversity. The random community structure and spatial constraints may also contribute to the overall hump‐shaped pattern. Beta diversity of bird communities in Gyirong Valley could be explained by the combination of different factors but is mainly shaped by the spatially structured environmental factors, especially contemporary climate.

Assessing agreement among alternative climate change projections to inform conservation recommendations in the contiguous United States

Addressing uncertainties in climate vulnerability remains a challenge for conservation planning. We evaluate how confidence in conservation recommendations may change with agreement among alternative climate projections and metrics of climate exposure. We assessed agreement among three multivariate estimates of climate exposure (forward velocity, backward velocity, and climate dissimilarity) using 18 alternative climate projections for the contiguous United States. For each metric, we classified maps into quartiles for each alternative climate projections, and calculated the frequency of quartiles assigned for each gridded location (high quartile frequency = more agreement among climate projections). We evaluated recommendations using a recent climate adaptation heuristic framework that recommends emphasizing various conservation strategies to land based on current conservation value and expected climate exposure. We found that areas where conservation strategies would be confidently assigned based on high agreement among climate projections varied substantially across regions. In general, there was more agreement in forward and backward velocity estimates among alternative projections than agreement in estimates of local dissimilarity. Consensus of climate predictions resulted in the same conservation recommendation assignments in a few areas, but patterns varied by climate exposure metric. This work demonstrates an approach for explicitly evaluating alternative predictions in geographic patterns of climate change.

Community level niche overlap and broad scale biogeographic patterns of bee communities are driven by phylogenetic history

AbstractAimBecause the ecological similarity between species is expected to increase with relatedness and that speciation is a local process, phylogeny may provide a common measure for the influence of ecological and biogeographic processes on community assembly. We tested if similarities in floral visitation patterns within communities and the phylogenetic beta‐diversity among communities were related to the position of bees within the bee phylogeny.LocationGlobal.MethodsWe combined a genus level phylogeny with within‐genera phylogenies for the bee species occurring within 18 globally distributed bee‐flower networks. Networks consisted of a matrix of bee and plant species and information on whether or not a bee species had been observed visiting flowers of a given plant species. For each network, we used Abouheif's Cmean to test if the similarity in floral associations (niche similarity) between bees and the number of plant species visited displayed a significant phylogenetic signal. To test if biogeography influenced the relatedness among species within networks we tested if the phylogenetic beta‐diversity increased with geographical distance and dissimilarity in climatic conditions among networks.ResultsWe found a phylogenetic signal for niche similarity in only 50% of the bee‐flower networks. However, network size influenced the likelihood of observing a phylogenetic signal and for seven of the eight bee‐flower networks with >20 species it was statistically significant. On a global scale, the phylogenetic beta‐diversity increased with geographical distances and with climatic dissimilarity between sites.Main conclusionsBee communities are structured by processes of speciation and migration so that regional species pools are dominated by a subset of the global phylogenetic clades, resulting in increasing phylogenetic beta‐diversity with geographical distance. Moreover, ecological filtering processes operating at both local (floral resource use) and continental (climatic constraints) scale determine the distribution of species among resources and geographical regions. The assembly of bee communities should therefore be understood as a product of both biogeographic and community ecological processes.

Climate extremes are associated with invertebrate taxonomic and functional composition in mountain lakes.

Climate change is expected to increase climate variability and the occurrence of extreme climatic events, with potentially devastating effects on aquatic ecosystems. However, little is known about the role of climate extremes in structuring aquatic communities or the interplay between climate and local abiotic and biotic factors. Here, we examine the relative influence of climate and local abiotic and biotic conditions on biodiversity and community structure in lake invertebrates. We sampled aquatic invertebrates and measured environmental variables in 19 lakes throughout California, USA, to test hypotheses of the relationship between climate, local biotic and environmental conditions, and the taxonomic and functional structure of aquatic invertebrate communities. We found that, while local biotic and abiotic factors such as habitat availability and conductivity were the most consistent predictors of alpha diversity, extreme climate conditions such as maximum summer temperature and dry‐season precipitation were most often associated with multivariate taxonomic and functional composition. Specifically, sites with high maximum temperatures and low dry‐season precipitation housed communities containing high abundances of large predatory taxa. Furthermore, both climate dissimilarity and abiotic dissimilarity determined taxonomic turnover among sites (beta diversity). These findings suggest that while local‐scale environmental variables may predict alpha diversity, climatic variability is important to consider when projecting broad‐scale aquatic community responses to the extreme temperature and precipitation events that are expected for much of the world during the next century.

The dual role of Andean topography in primary divergence: functional and neutral variation among populations of the hummingbird, Metallura tyrianthina.

BackgroundThe ridges and valleys of the Andes create physical barriers that limit animal dispersal and cause deterministic local variation in rainfall. This has resulted in physical isolation of animal populations and variation in habitats, each of which has likely contributed to the evolution of high species diversity in the region. However, the relative influences of geographic isolation, ecoclimatic conditions, and their potential interactions remain poorly understood. To address this, we compared patterns of genetic and morphological diversity in Peruvian populations of the hummingbird Metallura tyrianthina.ResultsPhylogenetic and variation partitioning analyses showed that geographic isolation rather than climatic dissimilarity explained the greatest proportion of genetic variance. In contrast, bill length variation was explained by climatic seasonality, but not by genetic divergence. We found that mutation-scaled migration rate (m) between persistently humid and semi-humid environments was nearly 20 times higher when the habitats were contiguous (m = 39.9) than when separated by a barrier, the Cordillera de Vilcanota (m = 2.1). Moreover, the population experiencing more gene flow exhibited a lesser degree of bill length divergence despite similar differences in climate.ConclusionsGeographic isolation is necessary for genetic divergence. Ecological differences, represented here by climate characteristics, are necessary for functional divergence. Gene flow appears to hinder the evolution of functional traits toward local adaptive optima. This suggests that functional diversification requires geographic isolation followed or accompanied by a shift in ecological conditions. Andean topography causes both isolation and climatic variation, underscoring its dual role in biotic diversification.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0595-2) contains supplementary material, which is available to authorized users.

Contrasting spatio‐temporal climatic niche dynamics during the eastern and western invasions of spotted knapweed in North America

AbstractAimThe spotted knapweed (Centaurea stoebe), a plant native to south‐east and central Europe, is highly invasive in North America. We investigated the spatio‐temporal climatic niche dynamics of the spotted knapweed in North America along two putative eastern and western invasion routes. We then considered the patterns observed in the light of historical, ecological and evolutionary factors.LocationEurope and North America.MethodsThe niche characteristics of the east and west invasive populations of spotted knapweed in North America were determined from documented occurrences over 120 consecutive years (1890–2010). For this investigation, the 2.5 and 97.5 percentiles of values along temperature and precipitation gradients, as given by the two first axes of a principal components analysis (PCA), were calculated. We additionally measured the climatic dissimilarity between invaded sites and the native niche using a multivariate environmental similarity surface (MESS) analysis.ResultsAlong both invasion routes, the species established in regions with climatic conditions that were similar to those in the native niche. An initial spread in ruderal habitats always preceded spread in (semi‐)natural habitats. In the east, the niche gradually increased over time until it reached limits similar to the native niche. Conversely, in the west the niche abruptly expanded after an extended time lag into climates not occupied in the native range; only the native cold niche limit was conserved.Main conclusionsOur study reveals that different niche dynamics have taken place during the eastern and western invasions. This pattern indicates different combinations of historical, ecological and evolutionary factors in the two ranges. We hypothesize that the lack of a well‐developed transportation network in the west at the time of the introduction of spotted knapweed confined the species to a geographically and climatically isolated region. The invasion of dry rangelands may have been favoured during the agricultural transition in the 1930s by release from natural enemies, local adaptation and less competitive vegetation, but further experimental and molecular studies are needed to explain these contrasting niche patterns fully. Our study illustrates the need and benefit of applying large‐scale, temporally explicit approaches to understanding biological invasions.

Speciation in Caucasian lizards: climatic dissimilarity of the habitats is more important than isolation time

Given sufficient time and limited gene flow, evolutionary lineages tend to transform into separate species. Mechanisms preventing assimilation during repeated gene-flow events include divergent adaptations and the development of pre- or postzygotic isolation. We analysed the morphological and genetic boundaries of three species of the rock lizard clade Darevskia ‘rudis’ (Darevskia rudis, Darevskia valentini, and Darevskia portschinskii) in relation to the environment, and tried to reconstruct evolutionary pathways underlying the observed separation among the species. We studied the geographic distribution of the scalation traits, microsatellite genotypes, and mitochondrial haplotypes. Our analyses showed consistent morphological and genetic patterns at the centre of the ranges for each species, but asymmetric distribution of alleles and scalation characters within the current contact zones among the species. The genetic and morphological diversification of the clade has been shaped during glacial isolation in an area of Southern Caucasus, away from the Black Sea Coast. The ancestral lineage of D. portschinskii separated from the common D. rudis–D. valentini lineage in the middle Pleistocene, and the two latter lineages separated in relatively recent geological time. Neither of the lineages attained complete lineage sorting; moreover, isolation and migration modelling have helped to detect recombinant gene flow from D. rudis to D. portschinskii (but not to D. valentini). This is most likely linked with climatically more similar suitable habitats between D. rudis and D. portschinskii than between D. valentini and the other two species. In itself, the isolation period was insufficient for the development of intrinsic isolation mechanisms in the system studied. Thus, differential landscape-dependent selection within the contact zones is likely to have triggered the rapid development of isolation mechanisms.

Space can substitute for time in predicting climate-change effects on biodiversity.

"Space-for-time" substitution is widely used in biodiversity modeling to infer past or future trajectories of ecological systems from contemporary spatial patterns. However, the foundational assumption--that drivers of spatial gradients of species composition also drive temporal changes in diversity--rarely is tested. Here, we empirically test the space-for-time assumption by constructing orthogonal datasets of compositional turnover of plant taxa and climatic dissimilarity through time and across space from Late Quaternary pollen records in eastern North America, then modeling climate-driven compositional turnover. Predictions relying on space-for-time substitution were ∼72% as accurate as "time-for-time" predictions. However, space-for-time substitution performed poorly during the Holocene when temporal variation in climate was small relative to spatial variation and required subsampling to match the extent of spatial and temporal climatic gradients. Despite this caution, our results generally support the judicious use of space-for-time substitution in modeling community responses to climate change.

Selection of Provenances to Adapt Tropical Pine Forestry to Climate Change on the Basis of Climate Analogs

Pinus patula and Pinus tecunumanii play an important role in the forestry sector in the tropics and subtropics and, in recent decades, members of the International Tree Breeding and Conservation Program (Camcore) at North Carolina State University have established large, multi-site provenance trials for these pine species. The data collected in these trials provide valuable information about species and provenance choice for plantation establishment in many regions with different climates. Since climate is changing rapidly, it may become increasingly difficult to choose the right species and provenance to plant. In this study, growth performance of plantings in Colombia, Brazil and South Africa was correlated to the degree of climatic dissimilarity between planting sites. Results are used to assess the suitability of seed material under a changing climate for four P. patula provenances and six P. tecunumanii provenances. For each provenance, climate dissimilarities based on standardized Euclidean distances were calculated and statistically related to growth performances. We evaluated the two methods of quantifying climate dissimilarity with extensive field data based on the goodness of fit and statistical significance of the climate distance relation to differences in height growth. The best method was then used as a predictor of a provenance change in height growth. The provenance-specific models were used to predict provenance performance under different climate change scenarios. The developed provenance-specific models were able to significantly relate climate similarity to different growth performances for five out of six P. tecunumanii provenances. For P. patula provenances, we did not find any correlation. Results point towards the importance of the identification of sites with stable climates where high yields are achievable. In such sites, fast-growing P. tecunumanii provenances with a high but narrow growth optimum can be planted. At sites with climate change of uncertain direction and magnitude, the choice of P. patula provenances, with greater tolerance towards different temperature and precipitation regimes, is recommended. Our results indicate that the analysis of provenance trial data with climate similarity models helps us to (1) maintain plantation productivity in a rapidly changing environment; and (2) improve our understanding of tree species’ adaptation to a changing climate.

Effects of geographic distance and climatic dissimilarity on species turnover in alpine meadow communities across a broad spatial extent on the Tibetan Plateau

Understanding the underlying mechanisms that generate species turnover or beta diversity among biological communities is a central theme in ecology. Here, we distinguish the effects of geographic distance and climatic dissimilarity on species turnover of vascular plants in alpine meadow communities on the Tibetan Plateau in China. We calculated species turnover between each pair of 17 sites, using the Jaccard’s and Simpson’s indices. We selected six variables to quantify climate at each site, and subjected values of the climatic variables to a principal component analysis. We applied a variance partitioning approach to disentangle the effects of geographic distance and climatic dissimilarity on species turnover in alpine meadow communities. We also examined the effect of elevation variation on species turnover. Geographic distance and climate dissimilarity together explained 49.1 % of the variation in compositional difference between alpine meadow communities; the amount of the variation explained purely by geographic distance and purely by climatic dissimilarity was 6.8 % and 2.8 %, respectively. When geographic distance, climate dissimilarity, and elevation difference were included in an analysis, they together explained 55 % of the variation in compositional difference between alpine meadow communities; the pure effect of each of the three sets of explanatory variables was 4.8, 4.3, and 3.5 %, respectively. The fact that the vast majority of the variation explained by geographic distance and climatic dissimilarity cannot be independently attributed to either factor suggests that the two factors operate together in determining regional patterns of species composition in alpine meadows on the Tibetan Plateau.

Predicting potential climate change impacts with bioclimate envelope models: a palaeoecological perspective

ABSTRACTAim We assess the realism of bioclimate envelope model projections for anticipated future climates by validating ecosystem reconstructions for the late Quaternary with fossil and pollen data. Specifically, we ask: (1) do climate conditions with no modern analogue negatively affect the accuracy of ecosystem reconstructions? (2) are bioclimate envelope model projections biased towards under‐predicting forested ecosystems? (3) given a palaeoecological perspective, are potential habitat projections for the 21st century within model capabilities?Location Western North America.Methods We used an ensemble classifier modelling approach (RandomForest) to spatially project the climate space of modern ecosystem classes throughout the Holocene (at 6000, 9000, 11,000, 14,000, 16,000, and 21,000 YBP) using palaeoclimate surfaces generated by two general circulation models (GFDL and CCM1). The degree of novel arrangement of climate variables was quantified with the multivariate Mahalanobis distance to the nearest modern climatic equivalent. Model projections were validated against biome classifications inferred from 1460 palaeoecological records.Results Model accuracy assessed against independent palaeoecology data is generally low for the present day, increases for 6000 YBP, and then rapidly declines towards the last glacial maximum, primarily due to the under‐prediction of forested biomes. Misclassifications were closely correlated with the degree of climate dissimilarity from the present day. For future projections, no‐analogue climates unexpectedly emerged in the coastal Pacific Northwest but were absent throughout the rest of the study area.Main conclusions Bioclimate envelope models could approximately reconstruct ecosystem distributions for the mid‐ to late‐Holocene but proved unreliable in the Late Pleistocene. We attribute this failure to a combination of no‐analogue climates and a potential lack of niche conservatism in tree species. However, climate dissimilarities in future projections are comparatively minor (similar to those of the mid‐Holocene), and we conclude that no‐analogue climates should not compromise the accuracy of model predictions for the next century.

The role of non‐native plants and vertebrates in defining patterns of compositional dissimilarity within and across continents

ABSTRACTAim Human activities have led to the spread and establishment of increasing numbers of non‐native species. Here we assess whether non‐native plant and vertebrate species have affected species compositions within and across Europe and North America. We also assess the effects of intra‐continental species exchange using the example of vertebrates.Location European countries and North America (states in the contiguous United States and provinces of Canada).Methods We measured compositional dissimilarity of native and non‐native assemblages of vascular plants and vertebrates and related these patterns to climatic dissimilarity and geographical distance. We considered three categories of non‐native species (introduced after ad 1500), namely: those (1) originating outside of both continents, (2) native to one continent and non‐native to the other, and (3) native in a particular region of a continent but non‐native in another region.Results The presence of non‐native plants and vertebrates led to more homogeneous species compositions between continents and to less homogeneous species composition within Europe compared with the native assemblages. In North America, the presence of non‐native plants led to more homogeneous species compositions and the presence of non‐native vertebrates had no effect. Species compositions being more homogeneous than the native composition were found for the three categories of non‐native vertebrate species for both continents. Between continents, climate was a better predictor of compositional dissimilarity for non‐native plants, whereas for vertebrates the explanatory power of climate and geographical distance were comparable. By contrast, within continents, climate was a better predictor of compositional dissimilarity of both plants and vertebrates.Conclusions We found clear evidence for biotic homogenization as a consequence of species displacement. However, in relation to overall species richness this effect was rather small, indicating that floras and faunas are still quite distinct. Therefore, claiming that we already face homogeneous biotas might be premature, although clear indications are visible which should raise a note of caution, especially in the light of increasing globalization.

Organizational Climate Similarity and Performance: International Joint Ventures in Russia

This study examines how organizational climate dissimilarity between parent firms and the joint venture organization (JVO) affects joint venture performance. Data were obtained from interviews with the general manager of 40 IJVs and questionnaires were completed by top-level managers from both parents and the JVO (6 people / IJV). Results indicate that to have the best chance of success, it is important for a firm starting a joint venture to select a partner with an organizational climate similar to its own. Results also indicate that it is important to create an organizational climate at the JVO that is similar to the foreign parent's organizational climate.