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

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

10.5194/bg-2017-136 ◽

2017 ◽

Cited By ~ 2

Author(s):

Marijn Bauters ◽

Hans Verbeeck ◽

Miro Demol ◽

Stijn Bruneel ◽

Cys Taveirne ◽

...

Keyword(s):

South America ◽

Tropical Forest ◽

Nitrogen Availability ◽

Forest Composition ◽

South American ◽

Functional Composition ◽

Elevational Gradients ◽

Species Shift ◽

Forest Biome

Abstract. Elevational gradients are an empirical tool to assess long-term forest responses to environmental change. We studied whether functional composition of tropical forest along elevational gradients in South America and in Africa showed similar shifts. We assessed community-weighted functional canopy traits and indicative δ15N shifts along two new altitudinal transects in the tropical forest biome of both South-America and Africa. We found that the functional forest composition response along both transects was parallel, with a species 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 two empirical indications that both South-American and African tropical forest show a parallel response along altitude, driven by nitrogen availability along the altitudinal gradients, inducing a parallel shift in the functional forest composition. This highlights the importance of nutrient availability for tropical forest in a changing world. More standardized research, and more research on other elevational gradients is needed to confirm our observations.

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Does foraging impact tropical forest composition?

10.5194/egusphere-egu21-8867 ◽

2021 ◽

Author(s):

Sijeh Asuk ◽

Nicholas Kettridge ◽

Jonathan Sadler ◽

Thomas Pugh ◽

Thomas Matthews ◽

...

Keyword(s):

Tropical Forest ◽

Tree Species ◽

Beta Diversity ◽

Basal Area ◽

Elevational Gradient ◽

Forest Composition ◽

Dissimilarity Index ◽

Elevational Gradients ◽

Edible Species ◽

The Impact

Growing evidence suggests that low-intensity anthropogenic activities affect ecological communities. The resultant changes in the forest structure and composition can also be influenced by elevational gradients. During foraging for food collection, humans can cover a wider spatially and elevational range compared to other high-intensity activities. These foraging activities can alter the species richness and evenness patterns either through preferential planting or intentionally or inadvertently influence the propagule pool. This study investigated the impact of foraging on forest composition and structure along an elevation gradient in Cross River National Park in the tropical rainforest zone of Nigeria. Fifteen permanent 40 x 40 m sample plots, covering an area of 2.4 hectares, were established in the forest located in the park along an elevational gradient of 120m to 460m. All trees of 10cm diameter at breast height (dbh) and above in all the plots were measured for dbh and identified to species level. Structured questionnaires on tree species utilization amongst forest-dependent rural communities were used to create edible and inedible tree species categories. Species abundance distributions were calculated at community level. Pairwise beta diversity between all plots along the elevational gradient was calculated using Sorensen&#8217;s dissimilarity index (&#946;sor) and the turnover component of &#946;sor using Simpson&#8217;s dissimilarity index (&#946;sim). A total of 35 edible species with a density of 128 stems/hectare and basal area of 11.99 m2/ha and 109 inedible species with a density of 364 stems/hectare and basal area of 22.42 m2/hectare were encountered. A reversed j-shaped function characteristic of a &#8216;natural&#8217; uneven-aged tropical forest stand was observed in the diameter size distribution for all species categories. The pairwise beta diversity trend of inedible species showed that there was a positive trend between beta diversity and elevation, and this was driven by turnover; the replacement of species in the species pool along the elevational gradient. In comparison, edible species differed significantly from inedible species and showed a negligible trend indicating that the species turnover was not enough to cause a change in beta diversity with increase in elevation. These results suggest that low-impact activities such as foraging may be subtly but notably altering the composition of tropical forest, perhaps by preferential planting, or influencing the propagule pool along elevational gradients. Further tests across a wider range of sites are required to assess if this is a widespread phenomenon and to identify the driving mechanisms.

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

10.1101/842138 ◽

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.

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

10.1101/420059 ◽

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.

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Geomorphic controls on elevational gradients of species richness

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1518922113 ◽

2016 ◽

Vol 113 (7) ◽

pp. 1737-1742 ◽

Cited By ~ 55

Author(s):

Enrico Bertuzzo ◽

Francesco Carrara ◽

Lorenzo Mari ◽

Florian Altermatt ◽

Ignacio Rodriguez-Iturbe ◽

...

Keyword(s):

Species Richness ◽

Abiotic Factors ◽

Null Model ◽

Elevational Gradient ◽

Elevational Gradients ◽

Complex Network Theory ◽

Local Species Richness ◽

Local Species ◽

A Site ◽

Zero Sum

Elevational gradients of biodiversity have been widely investigated, and yet a clear interpretation of the biotic and abiotic factors that determine how species richness varies with elevation is still elusive. In mountainous landscapes, habitats at different elevations are characterized by different areal extent and connectivity properties, key drivers of biodiversity, as predicted by metacommunity theory. However, most previous studies directly correlated species richness to elevational gradients of potential drivers, thus neglecting the interplay between such gradients and the environmental matrix. Here, we investigate the role of geomorphology in shaping patterns of species richness. We develop a spatially explicit zero-sum metacommunity model where species have an elevation-dependent fitness and otherwise neutral traits. Results show that ecological dynamics over complex terrains lead to the null expectation of a hump-shaped elevational gradient of species richness, a pattern widely observed empirically. Local species richness is found to be related to the landscape elevational connectivity, as quantified by a newly proposed metric that applies tools of complex network theory to measure the closeness of a site to others with similar habitat. Our theoretical results suggest clear geomorphic controls on elevational gradients of species richness and support the use of the landscape elevational connectivity as a null model for the analysis of the distribution of biodiversity.

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

10.32942/osf.io/sx9n8 ◽

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.

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Ice Core Studies of Global Biogeochemical Cycles

10.1007/978-3-642-51172-1 ◽

1995 ◽

Cited By ~ 3

Keyword(s):

Ice Core ◽

Biogeochemical Cycles ◽

Global Biogeochemical Cycles

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PALEOCLIMATIC AND PALEOECOLOGICAL RECONSTRUCTION OF A MIDDLE TO LATE EOCENE SOUTH AMERICAN SEASONALLY DRY TROPICAL FOREST

10.1130/abs/2019am-336594 ◽

2019 ◽

Author(s):

Camila Martínez ◽

◽

Carlos Jaramillo ◽

Jhonatan Martínez Murcia ◽

Federico Moreno ◽

...

Keyword(s):

Tropical Forest ◽

Late Eocene ◽

South American ◽

Seasonally Dry Tropical Forest ◽

Dry Tropical Forest ◽

Seasonally Dry

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

The Condor ◽

10.1093/ornithapp/duab009 ◽

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.

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Special Issue “Anaerobes in Biogeochemical Cycles”

Microorganisms ◽

10.3390/microorganisms9010023 ◽

2020 ◽

Vol 9 (1) ◽

pp. 23

Author(s):

Caroline M. Plugge ◽

Diana Z. Sousa

Keyword(s):

Essential Role ◽

Biogeochemical Cycles ◽

Special Issue ◽

Anaerobic Microorganisms ◽

Global Biogeochemical Cycles

Anaerobic microorganisms, Bacteria and Archaea, have an essential role in global biogeochemical cycles [...]

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