scholarly journals Eukaryotic Communities in Bromeliad Phytotelmata: How Do They Respond to Altitudinal Differences?

Diversity ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 326
Author(s):  
Eduardo Malfatti ◽  
Pedro M.A. Ferreira ◽  
Laura R. P. Utz
Keyword(s):  
Beta Diversity ◽  
Multivariate Analyses ◽  
Alpha Diversity ◽  
Mountain Range ◽  
Relative Importance ◽  
Southern Brazil ◽  
Ecological Studies ◽  
Gamma Diversity ◽  
Diversity Partitioning ◽  
One Year

Bromeliad phytotelmata are habitats for different organisms and models for ecological studies. Although poorly known, these environments are widely distributed in tropical ecosystems, harboring cosmopolitan and endemic species. Here, we investigated the diversity of the eukaryotic community in bromeliad phytotelmata considering the influence of altitude. We randomly sampled three bromeliad individuals (twice per season over one year) at four altitudinal strata (20 m, 400 m, 910 m, and 915 m) through a mountain range in southern Brazil. Species richness of phytotelmata community was higher at intermediate altitude while community-wide multivariate analyses revealed differences in phytotelmata communities at each height. Winter was the season with highest community richness, but a peak in summer was observed. Diversity partitioning in different spatial components showed that gamma diversity decreased linearly with altitude, whereas alpha diversity peaked at intermediate altitudes, and beta diversity decreased with height. The relative importance of the components of beta diversity showed different patterns according to the altitude: turnover was more important at intermediate and lower levels, while higher altitude communities were more nested. Our results indicate that differences in height affect diversity patterns of bromeliad phytotelmata communities, which were more diverse at lower altitudes in comparison with more homogeneous communities at higher levels.

Alpha, beta, or gamma: where does all the diversity go?

Paleobiology ◽  
1988 ◽  
Vol 14 (3) ◽  
pp. 221-234 ◽  
Author(s):  
J. John Sepkoski
Keyword(s):  
Beta Diversity ◽  
Alpha Diversity ◽  
Taxonomic Richness ◽  
Soft Bottom ◽  
Gamma Diversity ◽  
Data Set ◽  
Alpha And Beta Diversity ◽  
Community Or ◽  
Global Diversity ◽  
Measured Change

Global taxonomic richness is affected by variation in three components: within-community, or alpha, diversity; between-community, or beta, diversity; and between-region, or gamma, diversity. A data set consisting of 505 faunal lists distributed among 40 stratigraphic intervals and six environmental zones was used to investigate how variation in alpha and beta diversity influenced global diversity through the Paleozoic, and especially during the Ordovician radiations. As first shown by Bambach (1977), alpha diversity increased by 50 to 70 percent in offshore marine environments during the Ordovician and then remained essentially constant for the remainder of the Paleozoic. The increase is insufficient, however, to account for the 300 percent rise observed in global generic diversity. It is shown that beta diversity among level, soft-bottom communities also increased significantly during the early Paleozoic. This change is related to enhanced habitat selection, and presumably increased overall specialization, among diversifying taxa during the Ordovician radiations. Combined with alpha diversity, the measured change in beta diversity still accounts for only about half of the increase in global diversity. Other sources of increase are probably not related to variation in gamma diversity but rather to appearance and/or expansion of organic reefs, hardground communities, bryozoan thickets, and crinoid gardens during the Ordovician.

scholarly journals Diversity partitioning during the Cambrian radiation

2015 ◽  
Vol 112 (15) ◽  
pp. 4702-4706 ◽  
Author(s):  
Lin Na ◽  
Wolfgang Kiessling
Keyword(s):  
Beta Diversity ◽  
Plate Tectonics ◽  
Gamma Diversity ◽  
Diversity Partitioning ◽  
Alpha And Beta Diversity ◽  
Main Driver ◽  
Cambrian Radiation ◽  
High Predation ◽  
Geographic Regions ◽  
Global Biodiversity

The fossil record offers unique insights into the environmental and geographic partitioning of biodiversity during global diversifications. We explored biodiversity patterns during the Cambrian radiation, the most dramatic radiation in Earth history. We assessed how the overall increase in global diversity was partitioned between within-community (alpha) and between-community (beta) components and how beta diversity was partitioned among environments and geographic regions. Changes in gamma diversity in the Cambrian were chiefly driven by changes in beta diversity. The combined trajectories of alpha and beta diversity during the initial diversification suggest low competition and high predation within communities. Beta diversity has similar trajectories both among environments and geographic regions, but turnover between adjacent paleocontinents was probably the main driver of diversification. Our study elucidates that global biodiversity during the Cambrian radiation was driven by niche contraction at local scales and vicariance at continental scales. The latter supports previous arguments for the importance of plate tectonics in the Cambrian radiation, namely the breakup of Pannotia.

scholarly journals Ecological Approaches to Quantifying (Bio)Diversity in Music

2017 ◽  
Author(s):  
David G. Angeler ◽  
José Benavent-Corai
Keyword(s):  
Hypothesis Testing ◽  
Interdisciplinary Research ◽  
Beta Diversity ◽  
Alpha Diversity ◽  
Structural Diversity ◽  
Ecological Approach ◽  
Gamma Diversity ◽  
Knowledge Gaps ◽  
Structural Differentiation ◽  
Modeling Approaches

This paper introduces an ecological approach to quantifying diversity in musical compositions. The approach considers notations with distinct pitches and duration as equivalents of species in ecosystems, measures within a composition as equivalents of ecosystems, and the sum of measures (i.e., the entire composition) as a landscape in which ecosystems are embedded. Structural diversity can be calculated at the level of measures (“alpha diversity”) and the entire composition (“gamma diversity”). An additional metric can be derived that quantifies the structural differentiation between measures in a composition (“beta diversity”). We demonstrate the suitability of the approach in music using specifically composed examples and real songs that vary in complexity. We discuss the potential of the approach with selected examples from a potentially ample spectrum of applications within musicology research. The method seems particularly suitability for hypothesis testing to objectively identify many of the intricate phenomena in music. Because the approach extracts information present in the compositions – it lets the songs tell their structure – it can complement more complex modeling approaches used by music scholars. Combined such approaches provide opportunities for interdisciplinary research. They can help to fill knowledge gaps, stimulate further research and increase our understanding of music.

Diversification and diversity partitioning

Paleobiology ◽  
10.1666/13041 ◽  
2014 ◽  
Vol 40 (2) ◽  
pp. 162-176 ◽  
Author(s):  
Michael Hautmann
Keyword(s):  
Beta Diversity ◽  
Species Interactions ◽  
Early Stage ◽  
Alpha Diversity ◽  
Adaptive Divergence ◽  
Relative Role ◽  
Diversity Partitioning ◽  
Model Calculations ◽  
Alpha And Beta Diversity ◽  
Positive Effects

Model calculations predict that pathways of alpha- and beta-diversity in diversifying ecosystems notably differ depending on the relative role of competition, predation, positive effects of species' interactions, and environmental parameters. Four scenarios are discussed, in which alpha- and beta-diversity are modeled as a function of increasing gamma-diversity. The graphic illustration of this approach is herein called α-β-γ plot, in which the x-axis indicates increasing diversification rather than absolute time. In purely environmentally controlled systems, beta-diversity maintains near-maximum values throughout the diversification interval, whereas mean alpha-diversity increases linearly, with a slope being reciprocal to beta-diversity. A second scenario is based on the assumption that increasing richness will have predominantly positive effects on the addition of further species; here, alpha- and beta-diversity increase simultaneously (though not necessarily at the same rates) and without reaching a predictable upper limit. In ecosystems that are characterized by low competition between species, mean alpha-diversity asymptotically approaches a saturation level, whereas the increase in beta-diversity accelerates until alpha-diversity stagnates, and then continues to rise linearly. If competition is high, addition of species first increases beta-diversity until no further habitat contraction is possible, followed by a period in which alpha-diversity increase through adaptive divergence becomes the principal drive of diversification. Because there is a continuous transition between the late stage of the low-competition model and the early stage of the high-competition scenario, both can be combined in a single model of diversity partitioning under the premise of a diversity-dependent increase of competition. This summary model predicts three phases of diversity accumulation: (1) a niche overlap phase, (2) a habitat contraction phase, and (3) a niche differentiation phase. The models herein discussed provide a potential tool to assess the question which factors primary controlled the diversification of life over geological times.

scholarly journals Alpha-, beta-, and gamma-diversity of bacteria varies across global habitats

2020 ◽  
Author(s):  
Kendra E. Walters ◽  
Jennifer B.H. Martiny
Keyword(s):  
Beta Diversity ◽  
Multiple Scales ◽  
Agricultural Soils ◽  
Bacterial Species ◽  
Alpha Diversity ◽  
Global Scale ◽  
Gamma Diversity ◽  
Alpha And Beta Diversity ◽  
Alpha Beta ◽  
Beta And Gamma Diversity

AbstractBacteria are essential parts of ecosystems and are the most abundant organisms on the planet. Yet, we still do not know which habitats support the highest diversity of bacteria across multiple scales. We analyzed alpha-, beta-, and gamma-diversity of bacterial assemblages using 11,680 samples compiled by the Earth Microbiome Project. We found that soils contained the highest bacterial richness within a single sample (alpha-diversity), but sediment assemblages were the most diverse at a global scale (gamma-diversity). Sediment, biofilms/mats, and inland water exhibited the most variation in community composition among geographic locations (beta-diversity). Within soils, agricultural lands, hot deserts, grasslands, and shrublands contained the highest richness, while forests, cold deserts, and tundra biomes consistently harbored fewer bacterial species. Surprisingly, agricultural soils encompassed similar levels of beta-diversity as other soil biomes. These patterns were robust to the alpha- and beta-diversity metrics used and the taxonomic binning approach. Overall, the results support the idea that spatial environmental heterogeneity is an important driver of bacterial diversity.

scholarly journals Diversity of epiphyte ferns along an elevational gradient in El Triunfo Biosphere Reserve, southern Mexico

2020 ◽  
Vol 153 (1) ◽  
pp. 12-21
Author(s):  
Derio A. Jiménez-López ◽  
Rubén Martínez-Camilo ◽  
Nayely Martínez-Meléndez ◽  
Michael Kessler
Keyword(s):  
Linear Regression ◽  
Beta Diversity ◽  
Species Turnover ◽  
Cloud Forest ◽  
Alpha Diversity ◽  
Elevational Gradient ◽  
Mountain Range ◽  
Southern Mexico ◽  
Diversity Patterns ◽  
Individual Trees

Background and aims – In the tropics, some studies have found that the richness of epiphytic ferns present a peak at mountain mid-elevations. However, it is not well understood how transitions from tropical to subtropical conditions affect this peak, and even less is known about beta diversity of epiphytic ferns. Thus, the objective is to understand the effect of climatic gradients on the variation of local richness of ferns and beta diversity patterns along an elevational gradient in a mountain system in southern Mexico.Methods – We sampled 32 trees, each in four elevational bands (100–2200 m). Alpha diversity patterns were analysed using linear regression models. We used the Morisita index to quantify species turnover between bands. An additive partitioning approach was used to analyse the degree to which individual trees, plots, and bands contributed to total species richness. We evaluated the influence of climatic variables on species composition via linear regression models.Key results – A total of 30 species in five families were recorded. Each family contributed in different magnitude to the elevational richness pattern, with Polypodiaceae dominating due to its richness and presence along the entire transect. Alpha diversity at the three scales (αtree, αplot, αband) increased with elevation and rainfall, and with decreasing temperature. Species turnover was high along the gradient, but was scale-dependent, with βtransect (65–75%) and βband (14%) with the greatest contributing to total diversity. Although the contribution of the individual trees was lower, it increased with elevation. Conclusions – We emphasize the importance of including different scale levels in analyses of diversity along elevational gradients. In the region, cloud forest on the mountain peaks harbours the highest diversity of epiphytic fern communities. Due to a limited extent of this mountain range, the epiphyte ferns are susceptible to the effects of climate change.

scholarly journals Wildfire and topography drive woody plant diversity in a Sky Island mountain range in the Southwest USA

2021 ◽  
Author(s):  
Andrew Barton ◽  
Helen Poulos
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Woody Plant ◽  
Fire Severity ◽  
Alpha Diversity ◽  
Fire Regimes ◽  
Mountain Range ◽  
Gamma Diversity ◽  
In Fire ◽  
The Impact

Aim: Drastic changes in fire regimes are altering plant communities, inspiring ecologists to better understand the relationship between fire and plant species diversity. We examined the impact of a 2011 megafire on woody plant species diversity in an arid mountain range in southern Arizona, USA. We tested recent fire-diversity hypotheses by addressing the impact of the fire severity, fire variability, historic fire regimes, and topography on diversity. Location: Chiricahua National Monument, Chiricahua Mountains, Arizona. USA., part of the Sky Islands of the US-Mexico borderlands. Taxon: Woody plant species. Methods: We sampled woody plant diversity in 138 plots before (2002-2003) and after (2017-2018) the 2011 Horseshoe Two Megafire in three vegetation types and across fire severity and topographic gradients. We calculated gamma, beta, and alpha diversity and examined changes over time in burned vs. unburned plots and the shapes of the relationships of diversity with fire severity and topography. Results: Alpha species richness declined and beta and gamma diversity increased in burned but not unburned plots. Fire-induced enhancement of gamma diversity was confined to low fire severity plots. Alpha diversity did not exhibit a clear continuous relationship with fire severity. Beta diversity was enhanced by fire severity variation among plots and increased with fire severity up to very high diversity, where it declined slightly. Main Conclusions: The results reject the intermediate disturbance hypothesis for alpha diversity but weakly support it for gamma diversity. Spatial variation in fire severity promoted variation among plant assemblages, supporting the pyrodiversity hypothesis. Long-term drought probably amplified fire-driven diversity changes. Despite the apparent benign impact of the fire on diversity, the replacement of two large conifer species with shrubs signals the potential loss of functional diversity, emphasizing the importance of intervention to direct the transition to a novel vegetation mosaic.

scholarly journals The variability in the hydrosedimentological regime supports high phytoplankton diversity in floodplain: a 12-year survey of the Upper Paraná River

2017 ◽  
Author(s):  
Jascieli Carla Bortolini ◽  
Sueli Train ◽  
Luzia Cleide Rodrigues
Keyword(s):  
Beta Diversity ◽  
Alpha Diversity ◽  
Paraná River ◽  
Phytoplankton Composition ◽  
Gamma Diversity ◽  
Phytoplankton Diversity ◽  
River Floodplain ◽  
Parana River ◽  
Upper Paraná River Floodplain ◽  
Upper Paraná River

<p>The alpha, beta, and gamma diversity are important tools for conservation studies, and the distribution of species in space and time is essential to provided insights regarding diversity patterns and processes that modify the ecosystem and the community responses to such changes. Thus, a long-term ecological date was used to evaluate in 12 biotopes the phytoplankton composition and diversity within selected habitats (alpha diversity), between habitats (beta diversity) and across the upper Paraná River floodplain (gamma diversity). We evaluate the environmental variability of the hydrosedimentological cycles (limnophase and potamophase) during 12 years, associated with the water level variability and with the environmental heterogeneity as drivers of the phytoplankton composition and diversity in the upper Paraná River floodplain. Remarkable gamma diversity was recorded especially in limnophase, however, years with intense flood presented high gamma diversity, and years with extreme drought presented low gamma diversity, although without significant differences. The alpha diversity was significantly different on spatial and temporal scales. The beta diversity showed high values, however with low temporal variability and without correlation with the hydrosedimentological regime of the Paraná River. Overall, these results indicate that the variability in the hydrosedimentological regime associated with the periodicity, duration, and amplitude of limnophase and potamophase, and the pattern of mosaic of habitats in this floodplain are essential for sustaining much of the diversity phytoplankton diversity and ecosystem integrity, and that this approach is relevant and proved be useful to understand floodplain systems and associated phytoplankton community.</p>

Beta diversity and similarity of lichen communities as a sign of the times

2018 ◽  
Vol 50 (3) ◽  
pp. 371-383 ◽  
Author(s):  
Paolo GIORDANI ◽  
Giorgio BRUNIALTI ◽  
Marco CALDERISI ◽  
Paola MALASPINA ◽  
Luisa FRATI
Keyword(s):  
Rural Areas ◽  
Beta Diversity ◽  
Urban Areas ◽  
Alpha Diversity ◽  
Atmospheric Pollutants ◽  
Gamma Diversity ◽  
Effective Response ◽  
Epiphytic Lichen ◽  
Lichen Community

AbstractCurrently, change in lichen community structure depends on a combination of several pollutants instead of just one. Consequently, alpha lichen diversity no longer represents an effective response variable for assessing trends in atmospheric pollutants over time. Here we investigated the value of the relationship between alpha diversity and different aspects of gamma diversity (similarity, replacement and differences in richness of species) together with that of beta diversity (calculated as the sum of replacement and difference in richness of species), for assessing complex variations in epiphytic lichen communities in response to a changing pollution scenario. We considered an area subjected to extreme variation in atmospheric pollution in recent decades and explored temporal and spatial aspects of lichen community succession over short-, intermediate- and long-term reference periods. We found that variation in lichen communities for long- and intermediate-term reference periods was strongly dependent on the alpha diversity of single trees at the beginning of the observation period. The occurrence of nitrophytic species, which responded to the decrease in SO2 concentrations, contribute to this trend. The effect of land use was observed only over long observation periods, with trees in urban areas showing less variation than those located in rural areas. In particular, the analysis of similarity, species replacement and differences in richness of tree pairs demonstrated that trends and patterns within lichen communities are neither always nor to the same extent associated with alpha diversity. Our results show that a thorough study of gamma diversity, including beta diversity and similarity, is required to detect changes in air quality in long-term biomonitoring surveys.

scholarly journals Habitat Fragmentation Increases Overall Richness, but Not of Habitat-Dependent Species

2020 ◽  
Vol 8 ◽  
Author(s):  
Jordan Chetcuti ◽  
William E. Kunin ◽  
James M. Bullock
Keyword(s):  
Habitat Fragmentation ◽  
Land Cover ◽  
Habitat Loss ◽  
Beta Diversity ◽  
Alpha Diversity ◽  
Suitable Habitat ◽  
Gamma Diversity ◽  
Generalist Species ◽  
Species Groups ◽  
Per Se

Debate rages as to whether habitat fragmentation leads to the decline of biodiversity once habitat loss is accounted for. Previous studies have defined fragmentation variously, but research needs to address “fragmentation per se,” which excludes confounding effects of habitat loss. Our study controls for habitat area and employs a mechanistic multi-species simulation to explore processes that may lead some species groups to be more or less sensitive to fragmentation per se. Our multi-land-cover, landscape-scale, individual-based model incorporates the movement of generic species, each with different land cover preferences. We investigate how fragmentation per se changes diversity patterns; within (alpha), between (beta) and across (gamma) patches of a focal-land-cover, and if this differs among species groups according to their specialism and dependency on this focal-land-cover. We defined specialism as the increased competitive ability of specialists in suitable habitat and decreased ability in less suitable land covers compared to generalist species. We found fragmentation per se caused an increase in gamma diversity in the focal-land-cover if we considered all species regardless of focal-land-cover preference. However, critically for conservation, the gamma diversity of species for whom the focal land cover is suitable habitat declined under fragmentation per se. An exception to this finding occurred when these species were specialists, who were unaffected by fragmentation per se. In general, focal-land-cover species were under pressure from the influx of other species, with fragmentation per se leading to a loss of alpha diversity not compensated for by increases in beta diversity and, therefore, gamma diversity fell. The specialist species, which were more competitive, were less affected by the influx of species and therefore alpha diversity decreased less with fragmentation per se and beta diversity compensated for this loss, meaning gamma diversity did not decrease. Our findings help to inform the fragmentation per se debate, showing that effects on biodiversity can be negative or positive, depending on species’ competitive abilities and dependency on the fragmented land cover. Such differences in the effect of fragmentation per se would have important consequences for conservation. Focusing conservation efforts on reducing or preventing fragmentation in areas with species vulnerable to fragmentation.

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