scholarly journals Changes of arthropod diversity across an altitudinal ecoregional zonation in Northwestern Argentina

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4117 ◽  
Author(s):  
Andrea X. González-Reyes ◽  
Jose A. Corronca ◽  
Sandra M. Rodriguez-Artigas
Keyword(s):  
Species Richness ◽  
Polynomial Regression ◽  
Species Turnover ◽  
Predictor Variable ◽  
Elevational Gradient ◽  
Pitfall Trap ◽  
Northwestern Argentina ◽  
Higher Taxa ◽  
Total Species Richness ◽  
Wide Range

This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna) and two ecotones (Yungas-Monte and Prepuna) of Northwestern Argentina (altitudinal range of 2,500 m), and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500–4,000 m a.s.l) during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation–extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas) of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna). Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate) in addition to a geographic gradient (the distance of decay of similarity), demonstrating that the species turnover is important to explain the beta diversity along the elevational gradient. This suggests that patterns of diversity and distribution of arthropods are regulated by the dissimilarity of ecoregional environments that establish a wide range of geographic and environmental barriers, coupled with a limitation of species dispersal. Therefore, the arthropods of higher taxa respond differently to the altitudinal ecoregional zonation.

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.

Species richness is more important for ecosystem functioning than species turnover along an elevational gradient

2021 ◽  
Author(s):  
Jörg Albrecht ◽  
Marcell K. Peters ◽  
Joscha N. Becker ◽  
Christina Behler ◽  
Alice Classen ◽  
...  
Keyword(s):  
Species Richness ◽  
Ecosystem Functioning ◽  
Species Turnover ◽  
Elevational Gradient

Use of amphibians to define riparian zones of headwater streams

2006 ◽  
Vol 36 (9) ◽  
pp. 2124-2130 ◽  
Author(s):  
D W Perkins ◽  
M L Hunter, Jr.
Keyword(s):  
Species Richness ◽  
Repeated Measures ◽  
Headwater Streams ◽  
Pitfall Trap ◽  
Riparian Zones ◽  
Ecological Processes ◽  
Amphibian Species ◽  
Total Species Richness ◽  
Trap Location ◽  
Eurycea Bislineata

Riparian areas are known for their high species richness and their influence on ecological processes. However, riparian zones are difficult to define because of their ambiguous borders. Defining riparian zones by examining habitat use of species that require both terrestrial and aquatic environments is one method that has not been thoroughly examined. We sampled amphibians in Maine, USA, with pitfall traps located at five distances (1, 8, 18, 28, and 33 m) from 15 headwater streams. We captured 1897 amphibians of 10 species over 73 536 trap-nights. We used a repeated-measures analysis of variance to determine if species' capture rates varied among pitfall-trap locations. The highest numbers of three species, spring salamander (Gyrinophilus porphyriticus), two-lined salamander (Eurycea bislineata), and dusky salamander (Desmognathus fuscus), were captured in trap locations closest to the streams. Total species richness and average species richness were highest in the trap location located closest to the stream. We conclude that the riparian zone along headwater streams, as defined by amphibian species richness and abundance, is relatively narrow (7–9 m).

scholarly journals Medicinal plants of Nepal: Distribution pattern along an elevational gradient and effectiveness of existing protected areas for their conservation

1970 ◽  
Vol 19 (1) ◽  
pp. 16-22 ◽  
Author(s):  
KP Acharya ◽  
RP Chaudhary ◽  
OR Vetaas
Keyword(s):  
Species Richness ◽  
Medicinal Plants ◽  
Medicinal Plant ◽  
Protected Areas ◽  
Elevation Gradient ◽  
Predictor Variable ◽  
Elevational Gradient ◽  
Life Forms ◽  
Additive Models ◽  
Published Data

This study explores patterns of medicinal plant species richness along an elevational gradient in Nepal and the effectiveness of existing protected areas for their conservation. We used published data on the distribution of medicinal plants. The number of medicinal plants and the number of protected areas present in each 100 m elevation band were collated by interpolation. We tested the number of protected areas and the number of species as the response variables against elevation as a predictor variable. To explain the relationship between the total medicinal plant richness and their different life forms with elevation and protected areas, we used generalized additive models (GAMs) and scatter plots. The elevational distribution of medicinal plants as a whole and disaggregated into different life forms revealed hump-shaped patterns. The maximum richness of medicinal plants was found at an elevation of 1100 m a.s.l. but the maximum numbers of protected areas were found at elevations between 3000-3500 m a.s.l. There was negative correlation between the altitudinal distribution of protected areas and medicinal plants in Nepal. This study suggests that the protected areas of Nepal were less concentrated where medicinal plants diversity was rich. Key words: Elevation gradient, generalized additive model, medicinal plants, species richness   doi: 10.3126/banko.v19i1.2178 Banko Janakari, Vol. 19, No. 1, 16-22

An evaluation of methods for sampling ants (Hymenoptera: Formicidae) in British Columbia, Canada

2012 ◽  
Vol 144 (3) ◽  
pp. 491-507 ◽  
Author(s):  
R.J. Higgins ◽  
B.S. Lindgren
Keyword(s):  
British Columbia ◽  
Species Richness ◽  
Boreal Forests ◽  
Pitfall Trap ◽  
Assemblage Structure ◽  
Pitfall Traps ◽  
Pitfall Trapping ◽  
Nontarget Organisms ◽  
Total Species Richness ◽  
Total Species

AbstractAnts (Hymenoptera: Formicidae) are ubiquitous and of considerable ecological interest, yet poorly studied in Canada. Given their natural history attributes and relatively low density and diversity in cool boreal forests, there is a need to evaluate the applicability of commonly used approaches to sampling and analysis. We examined the relative utility of two pitfall trap designs, mini-Winkler litter extractions, and colony versus forager sampling for ecological studies. First, we found that Laurent (conventional) and Nordlander (modified to exclude larger nontarget organisms) pitfall traps were equally efficacious for estimating total species richness. Second, pitfall trapping yielded marginally higher total species richness than mini-Winkler litter sampling, by the incidence-based estimator (Chao2). Third, two studies considering the relationship between captures of individual ants in pitfall traps and identified ant colonies argued for caution in how pitfall captures are interpreted. In the first study, Nordlander traps placed in a grid surrounding nests ofFormica obscuripesForel revealed unique and highly patchy captures of individuals, with no patterns relating to proximity to the nest. In the second study, abundance estimates to compare ant assemblage structure in a simple grassland ecosystem by pitfall trapping (relative) and area-based hand sampling (absolute) for colonies, revealed that relative sampling does not reflect the absolute ant assemblage structure. Our results support, equivocally, the use of pitfall traps (Nordlander) over mini-Winklers in the cool moist forests of west-central British Columbia, but individual specimen counts should not be used when analysing the data.

scholarly journals Species turnover between age groups of horses and positive network of co-occurrences define the structure of horse strongylid communities: a meta-analysis

2021 ◽  
Author(s):  
Michel Boisseau ◽  
Nuria Mach ◽  
Marta Basiaga ◽  
Sławomir Kornaś ◽  
Tatiana Kuzmina ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Age Groups ◽  
Host Density ◽  
Community Diversity ◽  
Priority Effects ◽  
Sampling Effort ◽  
Age Classes ◽  
Recovery Method ◽  
Wide Range

Grazing horses are infected by a wide range of strongylid species mostly located in the large intestine. Despite their impact on equine health and the emergence of drug resistant isolates, the phenology of these nematodes has been poorly characterized and the rules structuring their assembly as a community are not understood. Here, we compiled data on 46 equine strongylid species collected worldwide at the regional or horse scales (upon deworming or after necropsy) to analyse their richness, diversity and associated factors of variation. Worldwide, twelve species from the Cylicocyclus (n = 4), Cylicostephanus (n = 3), Coronocyclus (n = 2) and Cyathostomum (n = 2) genera were found in at least 75% of sites. Geoclimatic conditions had a limited effect on strongylid communities, but reduced species richness was found under the temperate European area. The recovery method did not affect species richness and differences on the temporal and sampling effort scales between studies applying either methods underpinned heterogeneous variances in community diversity. At the horse level, rarefaction curves correlated poorly to parasite egg excretion, suggesting little contribution of community diversity to this trait. Using a diversity partitioning approach, we found that within-host diversity represented half of overall diversity underscoring the importance of host density and environmental contamination to the diversity of strongylid communities. While this is expected to erase diversity across communities, species turnover between age classes was the second most important contributor to overall diversity (23.9%). This was associated with a network of positive co-occurrences between the four most prevalent genera that we resolved at the anatomical niche level. Altogether this pattern of β-diversity maintenance across age classes combined with positive co-occurrences may be grounded by priority effects between major species. Our findings set the first assembly rules of equine strongylid communities.

scholarly journals Spatial patterns of species richness and nestedness in ant assemblages along an elevational gradient in a Mediterranean mountain range

2018 ◽  
Author(s):  
O. Flores ◽  
J. Seoane ◽  
V. Hevia ◽  
F.M. Azcárate
Keyword(s):  
Species Richness ◽  
Global Change ◽  
Spatial Patterns ◽  
Species Turnover ◽  
Elevational Gradient ◽  
Elevational Gradients ◽  
Cold Temperatures ◽  
Assemblage Composition ◽  
Ant Assemblages ◽  
High Elevations

AbstractThe study of biodiversity spatial patterns along ecological gradients can serve to elucidate factors shaping biological community structure and predict ecosystem responses to global change. Ant assemblages are particularly interesting as study cases, because ant species play a key role in many ecosystem processes and have frequently been identified as useful bioindicators. Here we analyzed the response of ant species richness and assemblage composition to elevational gradients in Mediterranean grasslands and subsequently tested whether these responses were stable spatially and temporally. We sampled ant assemblages in two years (2014, 2015) in two mountain ranges (Guadarrama, Serrota) in Central Spain, along an elevational gradient ranging from 685 to 2390 m a.s.l.Jackknife estimates of ant species richness ranged from three to 18.5 species and exhibited a hump-shaped relationship with elevation that peaked at mid range values (1100 - 1400 m). This pattern was transferable temporally and spatially. Elevation was significantly related to ant assemblage composition and facilitated separation of higher elevation assemblages (> 1700 m) from the remaining lower elevation species groups. Ant assemblages were nested; therefore species assemblages with a decreased number of species were a subset of the richer assemblages, although species turnover was more important than pure nestedness in all surveys. The degree of nestedness changed non-linearly as a cubic polynomial with elevation. These assembly patterns were observed over time but not between the two study regions.We concluded double environmental stressors typical of Mediterranean mountains explained species richness patterns: drought at low elevations and cold temperatures at high elevations likely constrained richness at both extremes of elevational gradients. The fact that species turnover showed a dominant role over pure nestedness suggested current ant assemblages were context-dependent (spatio-temporal factors) and highly vulnerable to global change, which threatens the conservation of present day native ant communities, particularly at high elevations.

Functional evenness of bird communities varies along the elevational gradient in Europe: Conservation implications

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Bird Species ◽  
Elevational Gradient ◽  
Negative Association ◽  
Bird Communities ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
Large Spatial Scale ◽  
Functional Evenness

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.

Unfinished Synthesis

1986 ◽  
Author(s):  
Niles Eldredge
Keyword(s):  
Modern Synthesis ◽  
Ernst Mayr ◽  
Conventional Theory ◽  
Higher Taxa ◽  
Evolutionary Thought ◽  
Wide Range ◽  
Theodosius Dobzhansky ◽  
George Gaylord Simpson

This study provides a stimulating critique of contemporary evolutionary thought, analyzing the Modern Synthesis first developed by Theodosius Dobzhansky, Ernst Mayr, and George Gaylord Simpson. The author argues that although only genes and organisms are taken as historic "individuals" in conventional theory, species, higher taxa, and ecological entities such as populations and communities should also be construed as individuals--an approach that yields the ecological and genealogical hierarchies that interact to produce evolution. This clearly stated, controversial work will provoke much debate among evolutionary biologists, systematists, paleontologists, and ecologists, as well as a wide range of educated lay readers.

scholarly journals Do carabids (Coleoptera: Carabidae) and chironomids (Diptera: Chironomidae) exhibit similar diversity and distributional patterns along a spatio-temporal gradient on a glacier foreland?

2018 ◽  
Author(s):  
Mauro Gobbi ◽  
Valeria Lencioni
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Aquatic Insect ◽  
Taxonomic Diversity ◽  
Carabid Beetles ◽  
Species Assemblages ◽  
Glacier Foreland ◽  
Distributional Patterns ◽  
Glacier Front ◽  
Spatio Temporal

Carabid beetles and chironomid midges are two dominant cold-adapted taxa, respectively on glacier forefiel terrains and in glacial-stream rivers. Although their sensitivity to high altitude climate warming is well known, no studies compare the species assemblages exhibited in glacial systems. Our study compares diversity and distributional patterns of carabids and chironomids in the foreland of the receding Amola glacier in central-eastern Italian Alps. Carabids were sampled by pitfall traps; chironomids by kick sampling in sites located at the same distance from the glacier as the terrestrial ones. The distance from the glacier front was considered as a proxy for time since deglaciation since these variables are positively correlated. We tested if the distance from the glacier front affects: i) the species richness; ii) taxonomic diversity; and iii) species turnover. Carabid species richness and taxonomic diversity increased positively from recently deglaciated sites (those c. 160 m from the glacier front) to sites deglaciated more than 160yrs ago (those located >1300 m from glacier front). Species distributions along the glacier foreland were characterized by mutually exclusive species. Conversely, no pattern in chironomid species richness and turnover was observed. Interestingly, taxonomic diversity increased significantly: closely related species were found near the glacier front, while the most taxonomically diverse species assemblages were found distant from the glacier front. Increasing glacial retreat differently affect epigeic and aquatic insect taxa: carabids respond faster to glacier retreat than do chironomids, at least in species richness and species turnover patterns.

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