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.

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 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.

Biogeographical regionalisation of Colombia: a revised area taxonomy

Phytotaxa ◽  
2021 ◽  
Vol 484 (3) ◽  
pp. 247-260
Author(s):  
CARLOS E. GONZÁLEZ-OROZCO
Keyword(s):  
Cluster Analysis ◽  
Species Richness ◽  
Plant Species ◽  
Spatial Patterns ◽  
Species Turnover ◽  
Land Plants ◽  
Geospatial Analyses ◽  
Areas Of Endemism ◽  
Biogeographic Regions ◽  
Definition Of

This study proposes a biogeographical regionalisation of Colombia based on geospatial analyses of plant species turnover and a revised area taxonomy. The spatial patterns of species turnover are calculated for 20,342 plant species in continental Colombia with distributions estimated from 271,568 georeferenced records aggregated to 414 (~50 km) grid cells across Colombia. The proposed biogeographic regions are defined by applying an agglomerative cluster analysis using a matrix of pairwise Simpson’s beta (bsim) dissimilarity values. Three main centres of species richness and 25 areas of endemism were identified across Colombia, complementing the definition of regionalisation. Biogeographical regionalisation comprises two dominions (Pacific and Boreal Brazilian), six provinces (Chocó-Darién, Guajira, Magdalena, Paramo, Sabana and Imerí) and thirty-five districts. The revised area taxonomy provides an updated and objective biogeographical classification for Colombia and is the first biogeographic regionalisation exclusively based on the taxic distributional overlap of Colombia´s land plants.

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

scholarly journals Species richness and β-diversity patterns of macrolichens along elevation gradients across the Himalayan Arc

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Subzar Ahmad Nanda ◽  
Manzoor-ul Haq ◽  
S. P. Singh ◽  
Zafar A. Reshi ◽  
Ranbeer S. Rawal ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Turnover ◽  
Elevation Gradient ◽  
Conservation Strategies ◽  
Elevational Gradients ◽  
Elevation Gradients ◽  
Diversity Patterns ◽  
Β Diversity ◽  
Shaped Pattern ◽  
The Himalaya

AbstractUnderstanding the species richness and β-diversity patterns along elevation gradients can aid in formulating effective conservation strategies particularly in areas where local anthropogenic stresses and climate change are quite significant as in the Himalaya. Thus, we studied macrolichen richness and β-diversity along elevational gradients at three sites, namely Kashmir (2200 to 3800 m a.m.s.l), Uttarakhand (2000–3700 m a.m.s.l) and Sikkim (1700 to 4000 m a.m.s.l) which cover much of the Indian Himalayan Arc. In all, 245 macrolichen species belonging to 77 genera and 26 families were collected from the three sites. Only 11 species, 20 genera and 11 families were common among the three transects. Despite the differences in species composition, the dominant functional groups in the three sites were the same: foliose, fruticose and corticolous forms. The hump-shaped elevation pattern in species richness was exhibited by most of the lichen groups, though an inverse hump-shaped pattern was also observed in certain cases. β-diversity (βsor) based on all pairs of comparisons along an elevation gradient varied from 0.48 to 0.58 in Kashmir, 0.03 to 0.63 in Uttarakhand and 0.46 to 0.77 in Sikkim. The contribution of turnover to β-diversity was more than nestedness at all the three transects. Along elevation β-diversity and its components of turnover and nestedness varied significantly with elevation. While species turnover increased significantly along the elevation in all the three transects, nestedness decreased significantly in Kashmir and Sikkim transects but increased significantly in the Uttarakhand transect. Except for the Kashmir Himalayan elevation transect, stepwise β-diversity and its components of turnover and nestedness did not vary significantly with elevation. The present study, the first of its kind in the Himalayan region, clearly brings out that macrolichen species richness, β-diversity, and its components of turnover and nestedness vary along the elevation gradients across the Himalayan Arc. It also highlights that contribution of turnover to β-diversity is higher in comparison to nestedness at all the three transects. The variations in species richness and diversity along elevation gradients underpin the importance of considering elevational gradients in planning conservation strategies.

scholarly journals Dimensions of passerine biodiversity along an elevational gradient: a nexus for historical biogeography and contemporary ecology

2019 ◽  
Author(s):  
Kevin R. Burgio ◽  
Steven J. Presley ◽  
Laura M. Cisneros ◽  
Katie E. Davis ◽  
Lindsay M. Dreiss ◽  
...  
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Biosphere Reserve ◽  
Elevational Gradient ◽  
Historical Biogeography ◽  
Relative Importance ◽  
Functional Biodiversity ◽  
Elevational Gradients ◽  
Evolutionary Mechanisms ◽  
Peruvian Andes

ABSTRACTAimThe incorporation of functional and phylogenetic information is necessary to comprehensively characterize spatial patterns of biodiversity and to evaluate the relative importance of ecological and evolutionary mechanisms in molding such patterns. We evaluated the relative importance of mechanisms that shape passerine biodiversity along an extensive elevational gradient.LocationManu Biosphere Reserve in the Peruvian AndesTaxonSongbirds (order Passeriformes)MethodsWe quantified elevational gradients of species richness, phylogenetic biodiversity, and functional biodiversity for all passerines as well as separately for suboscines and oscines; determined if phylogenetic or functional biodiversity was consistent with random selection or if there was evidence of particular mechanisms dominating community assembly; and compared patterns for each dimension of biodiversity for the two suborders.ResultsFor all passerines and for suboscines, species richness decreased in a saturating fashion, phylogenetic biodiversity declined linearly, and functional biodiversity was stochastic along the elevation gradient. For oscines, species richness and phylogenetic biodiversity decreased linearly, and functional biodiversity decreased in a saturating fashion.Main conclusionsElevational gradients of biodiversity at Manu result from a combination of adaptations associated with radiations that occurred elsewhere (suboscines in Amazonian lowlands, oscines in colder climes of North America) and an in situ radiation in the Andes (tanagers). Our results suggest a combination of temperature-related physiological constraints and a reduction in functional redundancy associated with decreasing resource abundance at higher elevations molded the passerine assemblages along this elevational gradient. Explicit consideration of historical biogeography and conservatism of ancestral niches is necessary to comprehensively understand the mechanisms that mold gradients of biodiversity.

scholarly journals Parallel functional and stoichiometric trait shifts in South American and African forest communities with elevation

2017 ◽  
Vol 14 (23) ◽  
pp. 5313-5321 ◽  
Author(s):  
Marijn Bauters ◽  
Hans Verbeeck ◽  
Miro Demol ◽  
Stijn Bruneel ◽  
Cys Taveirne ◽  
...  
Keyword(s):  
Species Richness ◽  
Tropical Forest ◽  
Nitrogen Availability ◽  
Elevational Gradient ◽  
Biogeochemical Cycles ◽  
Forest Composition ◽  
South American ◽  
Elevational Gradients ◽  
Future Directions ◽  
Global Biogeochemical Cycles

Abstract. The Amazon and Congo basins are the two largest continuous blocks of tropical forest with a central role for global biogeochemical cycles and ecology. However, both biomes differ in structure and species richness and composition. Understanding future directions of the response of both biomes to environmental change is paramount. We used one elevational gradient on both continents to investigate functional and stoichiometric trait shifts of tropical forest in South America and Africa. We measured community-weighted functional canopy traits and canopy and topsoil δ15N signatures. We found that the functional forest composition response along both transects was parallel, with a shift towards more nitrogen-conservative species at higher elevations. Moreover, canopy and topsoil δ15N signals decreased with increasing altitude, suggesting a more conservative N cycle at higher elevations. This cross-continental study provides empirical indications that both South American and African tropical forest show a parallel response with altitude, driven by nitrogen availability along the elevational gradients, which in turn induces a shift in the functional forest composition. More standardized research, and more research on other elevational gradients is needed to confirm our observations.

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