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opencc-zeroJan 2020View details →

Geographical gradients of genetic diversity and differentiation among the southernmost marginal populations of Abies sachalinensis revealed by EST-SSR polymorphism

Research Highlights: We detected the longitudinal gradients of genetic diversity parameters, such as the number of alleles, effective number of alleles, heterozygosity, and inbreeding coefficient, and found that these might be attributable to climatic conditions, such as temperature and snow depth. Background and Objectives: Genetic diversity among local populations of a plant species at its distributional margin has long been of interest in ecological genetics. Populations at the distribution center grow well in favorable conditions, but those at the range margins are exposed to unfavorable environments, and the environmental conditions at establishment sites might reflect the genetic diversity of local populations. This is known as the central-marginal hypothesis in which marginal populations show lower genetic variation and higher differentiation than do central populations. In addition, genetic variation in a local population is influenced by phylogenetic constraints and the population history of selection under environmental constraints. In this study, we investigated this hypothesis in relation to Abies sachalinensis, a major conifer species in Hokkaido. Materials and methods: A total of 1,189 trees from 25 natural populations were analyzed using 19 EST-SSR loci. Results: The eastern populations; namely, those in the species distribution center, showed greater genetic diversity than did the western peripheral populations. Another important finding is that the southwestern marginal populations were highly differentiated from the other populations. Conclusions: These differences might be due to genetic drift in the small and isolated populations at the range margin. Therefore, our results indicated that the central-marginal hypothesis held true for the southernmost A. sachalinensis populations in Hokkaido.

opencc-zeroNov 2023View details →

Is there a latitudinal diversity gradient for symbiotic microbes? A case study with sensitive partridge peas

Mutualism is thought to be more prevalent in the tropics than temperate zones and may therefore play an important role in generating and maintaining high species richness found at lower latitudes. However, results on the impact of mutualism on latitudinal diversity gradients are mixed, and few empirical studies sample both temperate and tropical regions. We investigated whether a latitudinal diversity gradient exists in the symbiotic microbial community associated with the legume Chamaecrista nictitans. We sampled bacteria DNA from nodules and the surrounding soil of plant roots across a latitudinal gradient (38.64 °N to 8.68 °N). Using 16S rRNA sequence data, we identified many non-rhizobial species within C. nictitans nodules that cannot form nodules or fix nitrogen. Species richness increased towards lower latitudes in the non-rhizobial portion of the nodule community but not in the rhizobial community. The microbe community in the soil did not effectively predict the non-rhizobia community inside nodules, indicating that host selection is important for structuring non-rhizobia communities in nodules. We next factorially manipulated the presence of three non-rhizobia strains in greenhouse experiments and found that co-inoculations of non-rhizobia strains with rhizobia had a marginal effect on nodule number and no effect on plant growth. Our results suggest that these non-rhizobia bacteria are likely commensals – species that benefit from associating with a host but are neutral for host fitness. Overall, our study suggests that temperate C. nictitans plants are more selective in their associations with the non-rhizobia community, potentially due to differences in soil nitrogen across latitude.

opencc-zeroJan 2024View details →

Drivers of plant diversity, community composition, functional traits and soil processes along an alpine gradient in the central Chilean Andes

The datasets in this repository include plant community surveys, hyperspectral reflectance data at the leaf and canopy level, leaf trait data, and soil chemistry data collected at five sites along an elevation gradient of 2400m-3500m in the Chilean Andes (33°S, 70°W). The purpose of this study was to evaluate the environmental drivers of community assembly processes along the elevation gradient.

opencc-by-4.0Dec 2015View details →

Table 1 in Latitudinal Diversity Gradients in Free-living Microorganisms - Hoogenraadia a Key Genus in Testate Amoebae Biogeography

Table 1. Characters and distribution of six species of the genus Hoogenraadia (L – length, W – width). Many of the earlier papers do not report a sample size for number of tests measured – so it is possible that some of these data may be based on a very low sample size.<table><tbody><tr><th>Species</th><th>Size (µm)</th><th>Distribution regions and publication</th><th>Habitats</th></tr></tbody><tbody><tr><th>H. africana</th><td>L = 95–115, W = 47–60</td><td>Moyen-Congo (Gauthier-Lièvre and Thomas 1958), Guinea and Equatorial Guinea (Golemansky 1962), Brasil (Leiptniz et al. 2003), China (Qin et al. 2011)</td><td>Sphagnum, water, river, forest marsh</td></tr><tr><th>H. asiatica</th><td>L = 95, W = 70</td><td>China (Wang and Min 1987)</td><td>Quaternary deposit</td></tr><tr><th>H. cryptostoma</th><td>L = 130–140, W = 105–110</td><td>Moyen-Congo (Gauthier-Lièvre and Thomas 1958), States of Parana, Mato Grosso du Sul, Brasil (Velho et al. 1996, 2000)</td><td>Swamp quite shady in the bed of a stream</td></tr><tr><th>H. humicola</th><td>L = 143–146, W = 96–100</td><td>Nepal, Himalayas (Bonnet 1977, 1978), Philippines (Bonnet 1980), Cote d’Ivoire, Africa (Bonnet 1976, 1978), Tonga and Western Samoa Islands (Korganova 1994), China (this paper)</td><td>Soils rich in organic debris in forest-gallery backwaters. The ground litter and sublitter horizons of white subtropical soils</td></tr><tr><th>H. ovata</th><td>L = 60–67, W = 36–39</td><td>Cote d’Ivoire, Africa (Bonnet 1976)</td><td>Soils rich in organic debris in forest-gallery backwaters</td></tr><tr><th>H. sylvatica</th><td>L = 82–93, W = 60–70</td><td>Punta Lara Province of Buenos Aires, Argentina (Vucetich 1974)</td><td>Moss in marginal forest</td></tr></tbody></table>

opencc-zeroNov 2021View details →

Data from: Environmental variation associated with topography explains butterfly diversity along a tropical elevation gradient

Few studies have evaluated the role of topography on the diversity patterns of biological communities along elevation gradients. We evaluated the influence of microclimate and vegetation structure associated with topographic variation on the richness and composition of species of different families of butterflies on a mountain located in a dry enclave (Chicamocha River Canyon) in the northern Andes, Colombia. We captured butterflies over four months at 18 elevations (300 to 1500 m a.s.l.) in two topographic positions (riverbed and hillslope) using an entomological net and traps baited with fermented fruit. In general, butterfly richness increased with elevation in both topographic positions. However, the richness-elevation relationship changed with butterfly family. The riverbed and hillslope sites host different assemblages of butterflies, and this pattern that was consistent for most families. In the riverbed, two sets of species are recognized along the elevation gradient (one below 700 m a.s.l. and the other above 1000 m a.s.l.), mainly owing to species replacement. On the hillslopes there was no clear pattern of grouping associated with elevation. Microclimate differences between the riverbed and hillslope sites along the elevation gradient were related to the vegetation structure and explained the variation in butterfly species composition. Our results highlight the role of topography not only by explaining the response of species richness and composition to environmental variation determined by elevation, but also as a factor that must be considered in the planning and management of biodiversity conservation in the mountains.

opencc-zeroJun 2022View details →

Trait functional diversity explains mixture effects on litter decomposition at the arid end of a climate gradient

Litter decomposition is controlled by climate, litter quality and decomposer communities. Because the decomposition of specific litter types is also influenced by the properties of adjacent types, mixing litter types may result in non-additive effects on overall decomposition rates. The strength of these effects seems to depend on the litter functional diversity. However, it is unclear which functional traits or combination of traits explain litter mixture effects and if these depend on the range of trait values and the ecosystems involved. These uncertainties hamper our ability to predict decomposition in plant communities. We aimed at understanding whether and how functional diversity (measured as functional dispersion, FDis) influences litter decomposition, and how this influence varies among different climates and across decomposition stages. We calculated FDis based on litter traits related to nutrient concentrations or to litter recalcitrance, and tested whether these diversity measures and climatic parameters (soil moisture and temperature) explained litter mixture effects on decomposition. Additive mixture effects (i.e. decomposition of mixtures equalling the mean decomposition of the single litter types) were common in most of the evaluated climates. Non-additive, negative effects were mainly restricted to the driest and warmest sites, and decreased with time. Non-additive effects increased in magnitude with the mixtures' FDis, with positive effects being related to FDis in nutrient traits and negative effects being related to FDis in recalcitrance traits. Synthesis: Litter mixing did not have strong effects on decomposition rates across the studied climatic gradient overall, and the direction and intensity of the mixture effects were context-dependent. The effects were stronger and more negative in the dryer ecosystems. Where effects were found, functional diversity calculated from selected groups of traits (related to nutrients or litter recalcitrance) predicted mixture effects, especially where trait ranges were broad, though much of the variation remains unexplained. We propose that functional diversity metrics based on litter traits that are mechanistically relevant, applied to diverse site-specific litter mixtures in different climates, can help to better understand under which conditions and in which direction litter diversity affects decomposition.

opencc-zeroAug 2022View details →

Exceptions to the rule: Relative roles of time, diversification rates and regional energy in shaping the inverse latitudinal diversity gradient

Aim: Inverse latitudinal diversity gradients (i-LDG), whereby regional richness peaks outside the tropics, have rarely been investigated and their causes remain unclear. Here, we investigate three prominent explanations, postulating that species-rich regions have had (1) longer time to accumulate species, (2) faster diversification, and (3) more energy to support more diverse communities. These mechanisms have been shown to explain the tropical megadiversity, and we examine whether they can also explain i-LDG. Location: Global Time period: Contemporary Major taxa studied: Amphibians, birds, mammals Methods: We estimated the time for species accumulation, regional diversification rates, and regional energy for six tetrapod taxa (≈ 800 species). Then, we quantified the relative effects and interactions among these three classes of variables, using variance partitioning, and confirmed the results across alternative metrics for time (community phylometrics and BioGeoBEARS), diversification rates (BAMM and DR), and regional energy (past and current temperature, productivity). Results: While regional richness across each of the six taxa peaked in the temperate region, it varied markedly across hemispheres and continents. The effects of time, diversification rates, and regional energy varied greatly from one taxon to another, but high diversification rates generally emerged as the best predictor of high regional richness. The effects of time and regional energy were limited, with the exception of salamanders and cetaceans. Main conclusions: Together, our results indicate that the causes of i-LDG are highly taxon-specific. Consequently, large-scale richness gradients might not have a universal explanation and different causal pathways might converge on similar gradients. Moreover, regional diversification rates might vary dramatically between similar environments and, depending on the taxon, regional richness might or might not depend on the time for species accumulation. Together, these results underscore the complexity behind the formation of richness gradients, which might involve a symphony of variations on the interplay of time, diversification rates, and regional energy.

opencc-zeroOct 2022View details →

Examining the diversity, stability and functioning of marine fish communities across a latitudinal gradient

Aim: As anthropogenic stressors on the biosphere intensify, understanding how communities respond to disturbances is critical. Biodiversity is often thought to promote the stability of communities over time and enhance ecosystem functioning. However, results have been inconsistent, and the multifaceted linkages among diversity, stability, and functioning under acute disturbances remain poorly understood. We experimentally tested the responses of marine fish communities to disturbance (i.e., acute habitat loss) across a diversity gradient spanning 35º degrees of latitude in the western Atlantic Ocean to assess the diversity-stability relationship and the interplay between diversity, stability, and fish biomass recovery (as a proxy for function) in marine fish communities. Location: Western Atlantic Ocean (Maine, Massachusetts, North Carolina, Florida [USA], Belize, and Panama). Time period: 2016 – 2017 Major taxa studied: Small, bottom-dwelling ('cryptobenthic') fishes Results: Diversity showed a negative effect on community stability at both the regional (across docks) and local (within docks) scales. Similarly, local diversity was negatively correlated with ecosystem function. These effects are exacerbated by the habitat loss imposed via our experimental treatment. Main conclusions: Our results suggest that habitat loss may more intensively re-shuffle diverse, tropical communities, which impacts biomass recovery, our proxy of functioning. Contrary to ecological theory, in small-bodied, benthos-associated vertebrate communities, biodiversity may neither promote stability nor functioning, suggesting that human disturbances may be particularly impactful in tropical, high-diversity ecosystems.

opencc-by-4.0May 2024View details →

Data from: Higher spatial than seasonal beta diversity of soil protists along elevation gradients

This data package contain the data and R script to reproduce the analyses of the paper from Bruni et al. (in press). It contains: <ul> <li>protist_spatiotemporal_turnover_site_parameters.xlsx: the list of sites used in this study with their (label, location, geography coordinates, habitat, ENA project and sample accessions) and soil abiotic parameters. Abbreviations and units are as follows: Res_hum, residual humidity [%]; Org_mat, soil organic matter [%]; C_org, organic carbon [mg ∙ g-1]; N_org, organic nitrogen [mg ∙ g-1]; P_bio, bioavailable phosphate [mg ∙ g-1]; C_N_ratio, carbon org. / nitrogen org. ratio; N_P_ratio: nitrogen org. / phosphorus bioavailable ratio.</li> <li>protist_spatiotemporal_turnover_data.RData: dataset in rda format (R core team, 2024) containing the ASV read's abundance per site matrix (object "mat"), the ASV taxonomic assignments (object "taxo"), the ASV sequences (object "asv") and the CRU-TS monthly climatic data corresponding to the sampled site's location and dates (object "cruts").</li> <li>protist_spatiotemporal_turnover_analyses.R: R script to reproduce all analyses and figures of Bruni et al. (in press)</li> </ul>   References: Bruni, E. P., Lorite, J., Peñas, J., Mulot, M., Fournier, B., Vittoz, P., Mitchell, E. A. D., & Lentendu, G. (2024). Higher spatial than seasonal beta diversity of soil protists along elevation gradients. Frontiers of Biogeography, 17, 1–17. DOI:<a href="https://doi.org/10.21425/fob.17.132637">10.21425/fob.17.132637</a> <div> <div>R Core Team. (2024). R: a language and environment for statistical computing (4.2.2) R Foundation for Statistical Computing. <a href="https://www.r-project.org/">https://www.r-project.org/</a></div> </div>

Fig. 4 in Patterns of Bird Diversity and Endemism Along an Elevational Gradient in the Southern Mexican Highlands.

Fig. 4. Rank-abundance curves for bird species at each of the four elevation sites in the Sierra Madre del Sur in southern Mexico. Bird species code: Aphelocoma sumichrasti (Asu), Catharus aurantiirostris (Cau), Cyanocitta coronata (Cco), Icterus pustulatus (Ipu), Junco phaeonotus (Jph), Melanerpes formicivorus (Mfo), Myadestes occidentalis (Moc), Myioborus miniatus (Mmi), Peucaea acuminata (Pac), Setophaga nigrescens (Sni), Tyrannus verticalis (Tve).

Fig. 5 in Patterns of Bird Diversity and Endemism Along an Elevational Gradient in the Southern Mexican Highlands.

Fig. 5. Differences in the abundance and composition of bird species per sampling point along an elevational gradient in the Sierra Madre del Sur in southern Mexico ordered by a non-metric multidimensional scaling based on the Bray-Curtis similarity index. Ellipses indicate 95% significance.

Fig. 2 in Patterns of Bird Diversity and Endemism Along an Elevational Gradient in the Southern Mexican Highlands.

Fig. 2. Bird species richness (q0) and diversity (q1 and q2) along an elevational gradient in the Sierra Madre del Sur in southern Mexico.

Fig. 1 in Patterns of Bird Diversity and Endemism Along an Elevational Gradient in the Southern Mexican Highlands.

Fig. 1. Geographic location of the (a) state of Guerrero in southern Mexico and (b) sampling sites (white triangles) within the Sierra Madre del Sur (red polygon). The nearest human settlements to each study site are shown as green stars.

Fig. 3 in Patterns of Bird Diversity and Endemism Along an Elevational Gradient in the Southern Mexican Highlands.

Fig. 3. Endemic bird species richness (q0) along an elevational gradient in the Sierra Madre del Sur in southern Mexico.

Fig. 6 in Patterns of Bird Diversity and Endemism Along an Elevational Gradient in the Southern Mexican Highlands.

Fig. 6. Faunal congruence curves for endemic bird species along an elevational gradient in the Sierra Madre del Sur in southern Mexico.

opencc-by-4.0Feb 2019View details →

Figure 1 in New species and new records of Aphelinus Dalman (Hymenoptera: Chalcidoidea: Aphelinidae) from Lagodekhi Reserve (Sakartvelo - Georgia), with diversity and distribution along an elevational gradient

Figure 1. Aphelinus lagodekhiensis sp. nov.: a, ♀ head and antenna; b, ♀ body; c, ♀ thorax; d, ♀ forewing.