scholarly journals Functional randomness despite high taxonomic turnover across an elevational gradient in a global biodiversity hotspot: A case study of hawkmoths and birds

2019 ◽  
Author(s):  
Mansi Mungee ◽  
Ramana Athreya
Keyword(s):  
Beta Diversity ◽  
Species Turnover ◽  
Geographic Distance ◽  
Elevational Gradient ◽  
Diversity Indices ◽  
Northeast India ◽  
Biodiversity Hotspot ◽  
Global Biodiversity ◽  
Patterns And Processes ◽  
Generalized Dissimilarity Modeling

AbstractAimWe examined the patterns and processes of taxonomic and functional dissimilarities for two disparate organismal groups (ectothermic hawkmoths and endothermic birds) across a broad tropical elevational gradient.LocationEaglenest Wildlife Sanctuary (northeast India), eastern Himalayan global biodiversity hotspot.Taxon4,731 hawkmoths; 15,387 birdsMethodsTurnover and nestedness components for taxonomic and functional dissimilarities were obtained using the methods developed by Baselga (2013) and Leprieur et al., 2012. We used Generalized Dissimilarity Modeling (GDM) with geographic distance, contemporary and historic climatic variables to assess the relative importance of dispersal and environmental processes in determining the beta diversity. Functional redundancy (FRed) was calculated for both organismal groups using the Simpson’s diversity indices. Null modeling was used to determine randomness in species and trait distributions.ResultsTurnover dominated taxonomic and functional dissimilarities, however the contribution of nestedness was considerably higher to the latter. Overall, the rate of dissimilarity with distance, for both facets of diversity, was significantly higher for birds, with stronger contributions of geographic distance and historic climate; whereas the hawkmoth dissimilarities were strongly correlated with only contemporary climate. Taxonomic dissimilarities deviated significantly from null, whereas functional dissimilarities exhibited high redundancy and randomness.Main ConclusionsOverall, our results suggest that while the drivers of beta-diversity exhibit idiosyncrasy and taxon-specificity; for a given taxa, they are consistent across the two facets of dissimilarity. More importantly, regardless of the principal predictor, the net result was that of high taxonomic turnover, which is de-coupled to a high degree from functional turnover in these tropical ecosystems. The large redundancy in trait values, despite high species turnover, indicates functional resilience of these tropical communities. The consistency of this pattern, across two disparate organismal groups, is suggestive of a key mechanism in which tropical communities may retain functionality of ecosystems in a changing environment.

Holy or Not, Israel is a Palaearctic Biodiversity Hotspot

2011 ◽  
Vol 57 (3) ◽  
pp. 207-211
Author(s):  
Yoni Gavish
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Grid Cell ◽  
Biodiversity Hotspot ◽  
Statistical Prediction ◽  
Β Diversity ◽  
Α Diversity ◽  
Species Area ◽  
Prediction Limits ◽  
Global Biodiversity

In their rebuttal to my comment, Roll et al. (2011) defend their original conclusion, by questioning the theoretical framework on which I based my analysis. They stress the importance of the statistical prediction limits and the treatment of latitudinal location as a covariate. They also add an additional grid-cell-based analysis. Here, I claim that even if provincial species-area relationships (SPAR) are not parallel, they are still different. While relying on Roll et al.'s (2011) analyses, I show that for each taxon there is at least one other provincial SPAR that lies considerably above the Palaearctic SPAR, making Palaearctic countries less favorable to be identified as a global biodiversity hotspot. I further claim that prediction limits should not be used to answer the question in focus and that adding latitude as a covariate does not alter the results. Finally, I address the grid-cell analyses of Roll et al. (2011), claiming that Israel's diversity lies mainly in the species turnover between cells (i.e., β diversity) and not on the average species richness within cells (α diversity). Therefore I hold on to my former conclusion that at least for three taxa—birds, mammals, and reptiles—Israel is indeed a Palaearctic provincial hotspot.

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.

Diversity, endemism and species turnover of millipedes within the south-western Australian global biodiversity hotspot

2009 ◽  
Vol 36 (10) ◽  
pp. 1958-1971 ◽  
Author(s):  
Melinda L. Moir ◽  
Karl E. C. Brennan ◽  
Mark S. Harvey
Keyword(s):  
Species Turnover ◽  
Biodiversity Hotspot ◽  
The South ◽  
Global Biodiversity ◽  
Western Australian

scholarly journals Frog species richness, composition and beta-diversity in coastal Brazilian restinga habitats

2008 ◽  
Vol 68 (1) ◽  
pp. 101-107 ◽  
Author(s):  
CFD. Rocha ◽  
FH. Hatano ◽  
D. Vrcibradic ◽  
M. Van Sluys
Keyword(s):  
Species Richness ◽  
Beta Diversity ◽  
Habitat Degradation ◽  
Species Turnover ◽  
Geographic Distance ◽  
Sampling Procedure ◽  
Brazilian Coast ◽  
Historical Factors ◽  
Frog Species ◽  
Diurnal Species

We studied the species richness and composition of frogs in 10 restinga habitats (sand dune environments dominated by herbaceous and shrubby vegetation) along approximately 1500 km of coastal areas of three Brazilian States: Rio de Janeiro (Grumari, Maricá, Massambaba, Jurubatiba and Grussaí), Espírito Santo (Praia das Neves and Setiba) and Bahia (Prado and Trancoso). We estimated beta-diversity and similarity among areas and related these parameters to geographic distance between areas. All areas were surveyed with a similar sampling procedure. We found 28 frog species belonging to the families Hylidae, Microhylidae, Leptodactylidae and Bufonidae. Frogs in restingas were in general nocturnal with no strictly diurnal species. The richest restinga was Praia das Neves (13 species), followed by Grussaí and Trancoso (eight species in each). The commonest species in the restingas was Scinax alter (found in eight restingas), followed by Aparasphenodon brunoi (seven areas). Our data shows that richness and composition of frog communities vary consistently along the eastern Brazilian coast and, in part, the rate of species turnover is affected by the distance among areas. Geographic distance explained approximately 12% of species turnover in restingas and about 9.5% of similarity among frog assemblages. Although geographic distance somewhat affects frog assemblages, other factors (e.g. historical factors, disturbances) seem to be also involved in explaining present frog assemblage composition in each area and species turnover among areas. The frog fauna along restinga habitats was significantly nested (matrix community temperature = 26.13°; p = 0.007). Our data also showed that the most hospitable restinga was Praia das Neves and indicated that this area should be protected as a conservation unit. Frog assemblage of each area seems to partially represent a nested subset of the original assemblage, although we should not ignore the importance of historical factors. This nestedness pattern, in part, probably results from the intensive fragmentation of restinga habitats. Possibly, many frog species may have been lost in some studied areas as a result of the extensive habitat degradation to which restinga habitats are presently exposed.

Species turnover drives the spatial distribution of frog beta diversity in farmland ponds

2019 ◽  
Vol 35 (4) ◽  
pp. 199-202 ◽  
Author(s):  
Henrique Nascimento Tavares ◽  
Fernando Rodrigues da Silva
Keyword(s):  
Spatial Distribution ◽  
Species Composition ◽  
Beta Diversity ◽  
Agricultural Landscape ◽  
Species Turnover ◽  
Land Use Changes ◽  
Geographic Distance ◽  
Forest Fragment ◽  
Inappropriate Use ◽  
Anuran Species

AbstractStudies integrating variation in species composition among sites are useful in understanding the impacts of land-use changes on the spatial distribution of biodiversity. However, the failure to recognize the distinction between beta diversity components, dissimilarity due to species replacement (i.e. turnover) and dissimilarity due to species loss from site to site (i.e. nestedness), can lead to inappropriate use of some indices. Here, we evaluated how the spatial distribution of anuran beta diversity components, turnover and nestedness, is associated with local and landscape descriptors in a tropical agricultural landscape with a recent history of agriculture expansion in south-eastern Brazil. Overall, 27 anuran species were found in the region with average ± SD species richness in each pool of 9.5 ± 3.5 species, ranging from 4 to 15 species. We observed that species turnover was the major component for anuran dissimilarity among pools, indicating that anuran species occurring in species-poor pools are not subsets of anuran species occurring in species-rich pools. Local variables and geographic distance were not important descriptors explaining the variation of anuran beta diversity. In contrast, the distance of the pools to the nearest forest fragment explained 16% of the variance in total beta diversity, 5% of the nestedness component and 2% of spatial turnover. Our results show that pools distributed across farmland landscapes are harbouring different anuran species composition, and together, these pools are contributing to the regional diversity of anurans in this region which is considered one of the most deforested and fragmented within Brazil.

Alpha- and beta- diversity of woody species across environmental gradients in African and Australian tropical savannas

2020 ◽  
Author(s):  
Felix Trotter ◽  
Caroline Lehmann ◽  
Keyword(s):  
Beta Diversity ◽  
Woody Plant ◽  
Environmental Gradients ◽  
Species Turnover ◽  
Geographic Distance ◽  
Alpha Diversity ◽  
Woody Species ◽  
Mean Annual Temperature ◽  
Alpha And Beta Diversity ◽  
Rainfall Seasonality

<p>Patterns of woody plant diversity in the tropical savanna biome has received little research attention but is relevant to understanding the complex vegetation dynamics of a biome that have remained contentious for almost a century. Tropical savannas of Africa and Australia are defined by the co-existence of woody plants and grasses, and the evolution and assembly of the savanna biome trace back 3-10 million years. Here, we explored patterns of local (alpha-) diversity and species turnover (beta-diversity) of woody plant species across African and Australian savannas. We aimed test the relative role of the environmental gradients of rainfall, temperature, fire and soil in shaping the relative abundance of all of woody species, genera, and families. Using generalized additive models (GAMs) and generalised dissimilarity models (GDMs) of field inventory data from vegetation plots across sub-Saharan Africa and Northern Australia we analysed changes in alpha- and beta-diversity. Environmental gradients were characterised as effective rainfall (ER), rainfall seasonality (coefficient of variation of monthly rainfall), mean annual temperature (MAT), temperature seasonality, fire frequency, and cation exchange capacity (CEC) in soils.</p><p>Savannas in Australia are on average drier and hotter than in Africa likely as a product of lower altitude. Crucially, diversity across all taxonomic levels is approximately two to three times greater in Africa compared with Australia. Within each continent, rainfall seasonality was the strongest environmental correlate of both alpha- and beta-diversity. In Africa, there is a strongly negative relationship between alpha-diversity at all taxonomic levels and rainfall seasonality. In contrast, in Australia, the relationship between alpha-diversity and rainfall seasonality while relevant is non-linear. Surprisingly within continents, rainfall, temperature, soils and fire had little bearing in these data on patterns of alpha diversity.</p><p>In terms of beta-diversity, and likely linked to the overall differences in diversity between continents, the geographic distance equalling total species turnover is greater in Australia than in Africa. Effective rainfall was the only additional significant correlate of woody species turnover in Australia, but only in arid regions. In Australia, at higher taxonomic levels the capacity of GDMs to explain variation in the data diminished substantially as a product of low diversity in genera and families. When compared to Australia, species turnover in Africa increases when geographic distance, rainfall seasonality and mean annual temperature are relatively low.</p><p>Our findings highlight that with ongoing climate change specifically with shifts in rainfall distribution that will also affect local drought regimes, rainfall seasonality could substantially alter patterns of diversity, specifically in Africa. There have been persistent attempts to explain ecosystem dynamics in savannas with respect to climate, soils and fire with emphasis often on total rainfall, but our findings suggest that rainfall seasonality can have strong effects on diversity that may interact with other environmental correlates such as fire.</p>

Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Survival Rates ◽  
Elevational Gradient ◽  
Forest Understory ◽  
Bird Abundance ◽  
Tropical Mountains ◽  
Demographic Rates ◽  
Understory Birds ◽  
Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

scholarly journals The biodiversity-wind energy-land use nexus in a global biodiversity hotspot

2021 ◽  
pp. 144471
Author(s):  
Vassiliki Kati ◽  
Christina Kassara ◽  
Zoi Vrontisi ◽  
Aristides Moustakas
Keyword(s):  
Land Use ◽  
Wind Energy ◽  
Biodiversity Hotspot ◽  
Global Biodiversity

scholarly journals Meta-analysis reveals severe pollen limitation for the flowering plants growing in East Himalaya-Hengduan Mountains region

BMC Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Xianfeng Jiang ◽  
Yanping Xie
Keyword(s):  
Confidence Interval ◽  
Pollen Limitation ◽  
Meta Analysis ◽  
Flowering Plants ◽  
Biodiversity Hotspot ◽  
Clear Relationship ◽  
Hengduan Mountains ◽  
Independent Data ◽  
The World ◽  
Global Biodiversity

Abstract Background Pollen limitation occurs widely and has an important effect on flowering plants. The East Himalaya-Hengduan Mountains region is a global biodiversity hotspot. However, to our knowledge, no study has synthetically assessed the degree of pollen limitation in this area. The present study aims to reveal the degree of pollen limitation for the flowering plants growing on East Himalaya-Hengduan Mountains and to test whether the reproductive features or the elevation is closely correlated with the degree of pollen limitation in this area. Results We complied data from 76 studies, which included 96 species and 108 independent data records. We found that the flowering plants in this area undergo severe pollen limitation [overall Hedges’ d = 2.004, with a 95% confidence interval (1.3264, 2.6743)] that is much higher than that of the flowering plants growing in many other regions around the world. The degree of pollen limitation was tested to determine the correlation with the capacity for autonomous self-reproduction and with the pollination pattern (generalized vs. specialized pollination) of plants. In addition, we found a clear relationship between elevation and the degree of pollen limitation, which indicates that plants might undergo more severe pollen limitation in relatively high places. Conclusions This paper is the first to address the severe pollen limitation of the flowering plants growing in East Himalaya-Hengduan Mountains region. Moreover, we reveal the positive correlation between elevation and the degree of pollen limitation.

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