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 Alpha and beta diversity patterns of polychaete assemblages across the nodule province of the eastern Clarion-Clipperton Fracture Zone (equatorial Pacific)

2020 ◽  
Vol 17 (4) ◽  
pp. 865-886 ◽  
Author(s):  
Paulo Bonifácio ◽  
Pedro Martínez Arbizu ◽  
Lénaïck Menot
Keyword(s):  
Fracture Zone ◽  
Beta Diversity ◽  
Species Turnover ◽  
Regional Scale ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Species Ranges ◽  
Diversity Patterns ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone

Abstract. In the abyssal equatorial Pacific Ocean, most of the seafloor of the Clarion-Clipperton Fracture Zone (CCFZ), a 6 million km2 polymetallic nodule province, has been preempted for future mining. In light of the large environmental footprint that mining would leave and given the diversity and the vulnerability of the abyssal fauna, the International Seabed Authority has implemented a regional management plan that includes the creation of nine Areas of Particular Environmental Interest (APEIs) located at the periphery of the CCFZ. The scientific principles for the design of the APEIs were based on the best – albeit very limited – knowledge of the area. The fauna and habitats in the APEIs are unknown, as are species' ranges and the extent of biodiversity across the CCFZ. As part of the Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI Oceans) pilot action “Ecological aspects of deep-sea mining”, the SO239 cruise provided data to improve species inventories, determine species ranges, identify the drivers of beta diversity patterns and assess the representativeness of an APEI. Four exploration contract areas and an APEI (APEI no. 3) were sampled along a gradient of sea surface primary productivity that spanned a distance of 1440 km in the eastern CCFZ. Between three and eight quantitative box cores (0.25 m2; 0–10 cm) were sampled in each study area, resulting in a large collection of polychaetes that were morphologically and molecularly (cytochrome c oxidase subunit I and 16S genes) analyzed. A total of 275 polychaete morphospecies were identified. Only one morphospecies was shared among all five study areas and 49 % were singletons. The patterns in community structure and composition were mainly attributed to variations in organic carbon fluxes to the seafloor at the regional scale and nodule density at the local scale, thus supporting the main assumptions underlying the design of the APEIs. However, the APEI no. 3, which is located in an oligotrophic province and separated from the CCFZ by the Clarion Fracture Zone, showed the lowest densities, lowest diversity, and a very low and distant independent similarity in community composition compared to the contract areas, thus questioning the representativeness and the appropriateness of APEI no. 3 to meet its purpose of diversity preservation. Among the four exploration contracts, which belong to a mesotrophic province, the distance decay of similarity provided a species turnover of 0.04 species km−1, an average species range of 25 km and an extrapolated richness of up to 240 000 polychaete species in the CCFZ. By contrast, nonparametric estimators of diversity predict a regional richness of up to 498 species. Both estimates are biased by the high frequency of singletons in the dataset, which likely result from under-sampling and merely reflect our level of uncertainty. The assessment of potential risks and scales of biodiversity loss due to nodule mining thus requires an appropriate inventory of species richness in the CCFZ.

Environmental correlates of herpetofaunal diversity in Costa Rica

2010 ◽  
Vol 26 (5) ◽  
pp. 521-531 ◽  
Author(s):  
David Laurencio ◽  
Lee A. Fitzgerald
Keyword(s):  
Costa Rica ◽  
Species Diversity ◽  
Beta Diversity ◽  
Geographic Distance ◽  
Alpha Diversity ◽  
High Elevation ◽  
Diversity Patterns ◽  
Regional Diversity ◽  
Environmental Correlates ◽  
High Elevation Site

Abstract:Disentangling local and historical factors that determine species diversity patterns at multiple spatial scales is fundamental to elucidating processes that govern ecological communities. Here we investigated how environmental correlates may influence diversity at local and regional scales. Primarily utilizing published species lists, amphibian and reptile alpha and beta diversity were assessed at 17 well-surveyed sites distributed among ecoregions throughout Costa Rica. The degree to which regional species diversity patterns were related to environmental variables and geographic distance was determined using Canonical Correspondence Analysis and Mantel tests. Amphibian alpha diversity was highest in lowland Pacific sites (mean = 43.3 species) and lowest at the high elevation site (9 species). Reptile alpha diversity values were high for both lowland Atlantic (mean = 69.5 species) and lowland Pacific (mean = 67 species) sites and lowest for the high elevation site (8 species). We found high species turnover between local sites and ecoregions, demonstrating the importance of beta diversity in the determination of regional diversity. For both amphibians and reptiles, beta diversity was highest between the high-elevation site and all others, and lowest among lowland sites within the same ecoregion. The effect of geographic distance on beta diversity was minor. Ecologically significant climatic variables related to rain, temperature, sunshine and insolation were found to be important determinants of local and regional diversity for both amphibians and reptiles in Costa Rica.

scholarly journals Species richness and beta diversity patterns of multiple taxa along an elevational gradient in pastured grasslands in the European Alps

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Veronika Fontana ◽  
Elia Guariento ◽  
Andreas Hilpold ◽  
Georg Niedrist ◽  
Michael Steinwandter ◽  
...  
Keyword(s):  
Species Richness ◽  
Beta Diversity ◽  
Elevational Gradient ◽  
European Alps ◽  
Diversity Patterns

scholarly journals Vascular Epiphytic Diversity in a Neotropical Transition Zone Is Driven by Environmental and Structural Heterogeneity

2019 ◽  
Vol 12 ◽  
pp. 194008291988220 ◽  
Author(s):  
Edilia de la Rosa-Manzano ◽  
Glenda Mendieta-Leiva ◽  
Antonio Guerra-Pérez ◽  
Karla María Aguilar-Dorantes ◽  
Leonardo Uriel Arellano-Méndez ◽  
...  
Keyword(s):  
Species Richness ◽  
Transition Zone ◽  
Forest Structure ◽  
Forest Type ◽  
Species Turnover ◽  
Cloud Forest ◽  
Size Variation ◽  
Alpha Diversity ◽  
Forest Types ◽  
Semideciduous Forest

Vascular epiphytes contribute significantly to tropical diversity. Research on the factors that determine vascular epiphytic diversity and composition in tropical areas is flourishing. However, these factors are entirely unknown in tropical-temperate transition zones, which represent the distribution limit of several epiphytic species. We assessed the degree to which climatic and structural variables determine the diversity of vascular epiphytic assemblages (VEAs) in a transition zone in Mexico: the El Cielo Biosphere Reserve. We found 12,103 epiphytic individuals belonging to 30 species and 15 genera along a climatic gradient from 300 to 2,000 m a.s.l. Bromeliaceae and Orchidaceae were the most species-rich families. Forests along the windward slope of the Sierra Madre Oriental (semideciduous forest and tropical montane cloud forest) had higher species richness than forests along the leeward slope (pine-oak forest and submontane scrub). Species richness was largely determined by seasonality and, to a lesser degree, by forest structure, whereas abundance was mainly determined by host tree size. Variation in VEAs composition was largely explained by climatic variables, whereas forest structure was not as important. VEAs differed among forest types and slopes in terms of taxonomic and functional composition. For example, certain bromeliad indicator species reflected differences between slopes. Although within-tree epiphytic species richness (alpha diversity) was low in this transition zone relative to other habitats, species turnover among forest types (beta diversity) was high. These findings suggest that each forest type makes a unique and important contribution to epiphytic diversity in this transition zone.

scholarly journals Robust, data-driven bioregionalizations emerge from diversity concordance

2021 ◽  
Author(s):  
Cristian S. Montalvo-Mancheno ◽  
Jessie Buettel ◽  
Stefania Ondei ◽  
Barry W. Brook
Keyword(s):  
Species Diversity ◽  
Beta Diversity ◽  
Alpha Diversity ◽  
Data Driven ◽  
Conservation Units ◽  
Conservation Action ◽  
Diversity Patterns ◽  
Alpha And Beta Diversity ◽  
Terrestrial Vertebrates ◽  
Site Diversity

Aim: Despite the increasing interest in developing new bioregionalizations and assessing the most widely accepted biogeographic frameworks, no study to date has sought to systematically define a system of small bioregions nested within larger ones that better reflect the distribution and patterns of biodiversity. Here, we examine how an algorithmic, data-driven model of diversity patterns can lead to an ecologically interpretable hierarchy of bioregions. Location: Australia. Time period: Present. Major taxa studied: Terrestrial vertebrates and vascular plants. Methods: We compiled information on the biophysical characteristics and species occupancy of Australia′s geographic conservation units (bioregions). Then, using cluster analysis to identify groupings of bioregions representing optimal discrete-species areas, we evaluated what a hierarchical bioregionalization system would look like when based empirically on the within- and between-site diversity patterns across taxa. Within an information-analytical framework, we then assessed the degree to which the World Wildlife Fund′s (WWF) biomes and ecoregions and our suite of discrete-species areas are spatially associated and compared those results among bioregionalization scenarios. Results: Information on biodiversity patterns captured was moderate for WWF′s biomes (50–58% for birds′ beta, and plants′ alpha and beta diversity, of optimal discrete areas, respectively) and ecoregions (additional 4–25%). Our plants and vertebrate optimal areas retained more information on alpha and beta diversity across taxa, with the two algorithmically derived biogeographic scenarios sharing 86.5% of their within- and between-site diversity information. Notably, discrete-species areas for beta diversity were parsimonious with respect to those for alpha diversity. Main conclusions: Nested systems of bioregions must systematically account for the variation of species diversity across taxa if biodiversity research and conservation action are to be most effective across multiple spatial or temporal planning scales. By demonstrating an algorithmic rather than subjective method for defining bioregionalizations using species-diversity concordances, which reliably reflects the distributional patterns of multiple taxa, this work offers a valuable new tool for systematic conservation planning.

Effects of habitat fragmentation on the diversity of epiphytic orchids from a montane forest of southern Mexico

2014 ◽  
Vol 31 (2) ◽  
pp. 103-115 ◽  
Author(s):  
Ezequiel Hernández-Pérez ◽  
Eloy Solano
Keyword(s):  
Species Turnover ◽  
Alpha Diversity ◽  
Montane Forest ◽  
Core Area ◽  
Edge Density ◽  
Southern Mexico ◽  
Epiphytic Orchids ◽  
Epiphytic Orchid ◽  
Tolerant Species ◽  
Shade Tolerant Species

Abstract:Epiphytic orchids are very diverse in montane forests, but fragmentation modifies this diversity. Twenty fragments were quantified to evaluate the effects of fragmentation on the alpha and beta diversities of epiphytic orchids in a montane forest located in southern Mexico. The following factors were evaluated: area, core area, shape, edge density, Euclidean nearest-neighbour distance fragment and contrast index. In each fragment, two transects of 2 × 50 m were drawn, and the trees with a diameter at breast height ≥ 20 cm were recorded. In each tree, the orchid species present were identified and quantified. Twenty-three species of epiphytic orchid in 234 phorophytes corresponding to 20 species were recorded. The epiphytic orchid richness per tree and species turnover was different between the phorophytes. The edge density and the contrast index had significant effects on the alpha diversity, while the isolation of the fragments significantly affected the beta diversity. The edge density positively affected the alpha diversity of the epiphytic orchids, likely through microclimatic changes caused by fragmentation. Drought-tolerant species were common on the edges of the fragments, and shade-tolerant species established on the core area of the fragments. This pattern most likely depends on the ecological range of the taxa, which is crucial to their development and persistence in fragmented habitats.

scholarly journals Alpha and beta diversity patterns of polychaete assemblages across the nodule province of the Clarion-Clipperton Fracture Zone (Equatorial Pacific)

2019 ◽  
Author(s):  
Paulo Bonifácio ◽  
Pedro Martinez-Arbizu ◽  
Lénaïck Menot
Keyword(s):  
Fracture Zone ◽  
Beta Diversity ◽  
Species Turnover ◽  
Regional Scale ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Species Ranges ◽  
Diversity Patterns ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone

Abstract. In the abyssal Equatorial Pacific Ocean, most of the seafloor of the Clarion-Clipperton Fracture Zone (CCFZ), a 6 million km2 polymetallic nodule province, has been preempted for future mining. In light of the large footprint that mining would leave, and given the diversity and the vulnerability of the abyssal fauna, the International Seabed Authority has implemented a regional management plan that includes the creation of nine areas of particular environmental interest (APEIs) located at the periphery of the CCFZ. The APEIs were defined based on the best – albeit very limited – scientific knowledge for the area. The fauna and habitats in the APEIs are unknown, as are species' ranges and the extent of biodiversity across the CCFZ. As part of the Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI Oceans) pilot action Ecological aspects of deep-sea mining, the SO239 cruise aimed at improving species inventories, determining species ranges, identifying the drivers of beta diversity patterns and assessing the representativeness of an APEI. Four exploration contract areas and an APEI (APEI#3) were sampled along a gradient of sea-surface primary productivity that spanned a distance of 1440 km in the eastern CCFZ. Between 3 and 8 quantitative box cores (0.25 m2; 0–10 cm) were sampled in each study area, resulting in a large collection of polychaetes that were morphologically and molecularly (COI and 16S genes) analyzed. A total of 275 polychaete morphotypes were identified. Only one morphotype was shared among all five study areas and 49 % were singletons. The patterns in community structure and composition were mainly attributed to variations in food fluxes at the regional scale and nodule density at the local scale. The four exploration contract areas belong to a mesotrophic province. The distance-decay of similarity among the four areas provides an estimated species turnover of 0.04 species km−1 and an average species range of 25 km. The polychaete assemblage in APEI#3 showed the lowest densities, lowest diversity as well as very low, distant-independent similarity with the other four study areas. Given that APEI#3 is located in an oligotrophic province and separated from the CCFZ by the Clarion Fracture Zone, our results call into question the representativeness and the appropriateness of APEI#3 to meet its purpose of preserving the biodiversity of the CCFZ fauna. Two methods for estimating the total number of polychaete species gave estimates that ranged from 498 to 240 000 species. Both methods are biased by the high frequency of singletons in the dataset, which likely result from under-sampling; our estimates thereby merely reflect our level of uncertainty. The assessment of potential risks and scales of biodiversity loss due to nodule mining thus requires an appropriate inventory of species richness in the CCFZ.

scholarly journals Historical signatures in the alpha and beta diversity patterns of Atlantic Forest harvestman communities (Arachnida: Opiliones)

2019 ◽  
Vol 97 (7) ◽  
pp. 631-643 ◽  
Author(s):  
A.A. Nogueira ◽  
C. Bragagnolo ◽  
M.B. DaSilva ◽  
T.K. Martins ◽  
E.P. Lorenzo ◽  
...  
Keyword(s):  
Protected Areas ◽  
Atlantic Forest ◽  
Beta Diversity ◽  
Alpha Diversity ◽  
Influential Factor ◽  
Conservation Strategies ◽  
Diversity Patterns ◽  
Alpha And Beta Diversity ◽  
Historical Factors ◽  
Compositional Changes

The integration of ecology and historical biogeography is fostering the investigation of diversity patterns. We studied alpha and beta diversity patterns of Brazilian Atlantic Forest harvestman (Arachnida: Opiliones) communities and related them to environmental and historical factors. Our data bank contains 508 species from 63 sites, encompassing almost the entire latitudinal range of Atlantic Forest. Alpha diversity was higher in coastal sites in the south and southeast regions and decreased in sites inland, as well as in sites in the coastal northeast region, especially in northern Bahia state. Alpha diversity was positively influenced by precipitation and altitudinal range, but the low number of species in northeastern coastal sites seems to be more related to the historical distribution of Neotropical harvestman lineages than to recent environmental factors. Geographic distance was the most influential factor for beta diversity. Compositional changes were also remarkably congruent with areas of endemism delimited for Atlantic Forest harvestmen. The percentage of protected areas for each area of endemism was very unbalanced, and Espírito Santo and Pernambuco states were the least protected areas. The turnover process observed in the compositional changes indicates that conservation strategies should include as many reserves as possible because every community presents a unique set of species.

scholarly journals Testing repeatability, testing repeatability, testing repeatability: harmonization of the DNA metabarcoding protocol for macrobenthos across Europe

2021 ◽  
Vol 4 ◽  
Author(s):  
Laure Van den Bulcke ◽  
Annelies De Backer ◽  
Magdalini Christodoulou ◽  
Sahar Khodami ◽  
Sara Maes ◽  
...  
Keyword(s):  
Beta Diversity ◽  
Pcr Amplification ◽  
Alpha Diversity ◽  
Ring Test ◽  
Diversity Patterns ◽  
Macrobenthic Communities ◽  
Number Of Species ◽  
Dna Metabarcoding ◽  
Low Diversity ◽  
The Impact

Macrobenthos is a good indicator to evaluate the potential effects of human activities on the marine benthic ecosystem. In environmental impact assessments (EIAs), macrobenthic species identification is typically based on morphological characteristics, a time-consuming and labor-intensive process for which specific taxonomic knowledge and experts are needed. DNA metabarcoding can circumvent most of these shortcomings. However, to be applicable in EIAs and to be adapted by policy, a standardized protocol that allows for reproducible and reliable DNA metabarcoding results is a prerequisite. Here, three research questions were investigated as part of the international Interreg NSR project GEANS: 1) “How many replicates of DNA extractions and PCR products are needed to capture most of the macrobenthic species in a sample?”, 2) “Is a ‘fixed’ DNA metabarcoding protocol repeatable across different institutes?” and 3) “What is the impact of small changes in this DNA metabarcoding protocol on alpha diversity?”. These are important steps to convince stakeholders that this efficient and quick method generates reliable and comparable results. First, variation in macrobenthic species across technical replicates was investigated in three biological replicates from three macrobenthic communities in the Belgian Part of the North Sea (BPNS) with high, medium and low diversity. For each biological replicate, six DNA replicates were taken and one of these DNA replicates was used to assess variation between three replicates for PCR amplification. Three DNA replicates were needed in locations with a high and medium diversity to pick up at least 80% of the species diversity present in the six replicates, while four DNA replicates were needed in the location with low diversity. Variation in the detected species between PCR replicates was high, illustrating the importance of including at least three PCR replicates in the lab protocol. Second, we conducted a ring test where subsamples of 12 bulk macrobenthos samples, originating from four different macrobenthic communities in the BPNS (differing in species density and diversity), were distributed to four institutes located in Belgium, the Netherlands, Germany and Denmark. Samples were processed using the same standardized lab protocol and the resulting datasets were processed bioinformatically by one institute. The number of ASVs and the number of species reflected the morphological diversity patterns, i.e. highest values for the replicates from the highly diverse macrobenthic community, lowest numbers in the low diversity replicates and intermediate values in the samples from the medium diversity community. These patterns were identical between the four institutes, showing high repeatability for alpha diversity when using the same protocol. In total, 100 macrobenthic species were detected through DNA metabarcoding, of which 60 species were picked up by all four institutes, while 0-14 species were recorded by only one of the four institutes. Beta diversity patterns were also comparable between the four institutes, as the nMDS plot clearly showed clustering based on the macrobenthic communities, independent of the institute that conducted the work. Finally, small changes to the lab protocol (different DNA extraction kit, different high fidelity polymerases for PCR amplification, different reagents for clean-up) resulted in only minor changes in alpha diversity: similar number of species were detected as with the fixed protocol in all samples and 70% - 75% of the species were shared between the ‘fixed’ and adjusted protocols. This study shows for the first time that DNA metabarcoding offers a highly repeatable assessment of alpha and beta diversity patterns, which supports the suitability of DNA metabarcoding for monitoring of marine macrobenthos. These results are highly valuable to establish a harmonized and uniform DNA metabarcoding protocol, to be used by all institutions in Europe when implemented as a new standard method in EIAs of the benthic ecosystem.

Sign in / Sign up

Export Citation Format

Share Document