Find research datasets worth reusing

Nitrogen transformation along an elevational and vegetative gradient from the Coweeta Hydrologic Laboratory from 1991 to 1995

Examination of N-transformation along elevation and vegetation gradient. These measurements are analysis of plant nitrogen availability and overall site productivity.

Variation in the relative effects of top-down and bottom-up forces on herbivores and herbivory along an elevational gradient in the southern Appalachian mountains in 2001

It is a well established fact that top-down (predation), bottom-up (resource availability) and lateral (interference) interactions are the dominant biotic forces in terrestrial ecosystems in addition to a host of other interactions like mutualism and symbiosis. The primary emphasis has always been to look for a singular mechanistic explanation in determining community dynamics. The ecological literature is replete with controversy on the subject of whether top-down or bottom-up forces predominate in ecosystems and their role in dynamics of ecological communities. The emerging consensus is that both top-down and bottom-up forces act in concert and the impetus is shifting towards the elucidation of the context, biotic and abiotic, under which these forces come into play. There are very few studies that have addressed this question and looked at the simultaneous interaction of these forces. I propose to study the effects of spatial heterogeneity in biotic and abiotic factors along an elevation gradient on the relative impacts of top-down and bottom-up forces and the result of their interactive effects on folivory. Specifically, I shall address the effects of spatial variation in plant quality and predation pressure and their interactive impacts on insect herbivore biomass and consumption. I shall also address the effects of complexity within/among trophic levels on the impact of these forces. The study aims to bring about a greater understanding of the role played by abiotic factors and complexity in community dynamics.

Elevational gradient in ant diversity in the Coweeta Hydrologic Laboratory in 2005

This study will examine spatial patterns of ant diversity, body size, and community composition along the elevational gradient at Coweeta. The data will be part of a larger study that will examine several gradients in the US and abroad to assess whether there are general mechanisms that shape these diversity gradients. Patterns of ant species diversity are well documented and yet the mechanisms promoting species coexistence among communities are often elusive. Two emerging hypotheses that account for coexistence in ant communities are the discovery-dominance tradeoff and the dominance-thermal tolerance tradeoff. Here we used behavioural assays and community-level sampling from ant assemblages in the southern Appalachians, USA to test for the discovery-dominance and dominance-thermal tolerance tradeoffs. The investigators involved were Nathan Sanders, Robert Dunn, JP Lessard, and Melissa Geraghty.

Measurements of Soil pH and Soil Cations Along an Elevational Gradient

This project is part of a larger examination of site productivity along an elevational gradient. Soil pH was measured at each site. A subset of soil samples were analyzed for soil cations, e.g., K, Ca, Mg, and PO4-P, at each of the five terrestrial gradient plots located at Coweeta Hydrologic Lab, Otto, NC.

Benthic organic matter (BOM) standing crops along the Ball Creek / Coweeta Creek elevational gradient at the Coweeta Hydrologic Laboratory from 1991 to 1992

We investigated how benthic organic matter (BOM) standing CR varied over space and time in the context of an elevational stream-size gradient. Samples were collected with a stratified random procedure to also study how BOM varied with respect to the major habitat patches within the stream. Habitat patch include cobble-riffle, sandy-reach, and rock. Benthic organic matter was collected efuarterly from streams draining a 9-yr-old clearcut, an 18-yr-old "old-field", a 25-yr-old successional forest, and two reference watersheds at Coweeta Hydrologic Laboratory in the Appalachian Mountains of North Carolina, USA. Samples were separated into large benthic organic matter (LBOM >1 mm) and fine benthic organic matter (FBOM <1 mm). An additional survey of large (>5 cm diam.) and small (1-5 cm diam.) wood was conducted. This study was conducted from 1991 to 1992.

openCC (other)Jan 2020View details →

Silicon content of canopy foliage along an elevation gradient near W6 at the Hubbard Brook Experimental Forest, 1998-2008

Leaf tissue was collected for the three dominant tree species; sugar maple (Acer saccharum Marsh.), American beech (Fagus grandifolia Erhr.), and yellow birch (Betula alleghaniensis Britt.) at the full-grown stage in August of each year. Individual leaves were collected from manually cut branches throughout the canopies of trees at different elevations in the Bear Brook area west of, and representative of, W6. Fifteen trees (five per species in the low, middle and high elevation zones) were sampled each year from 1998-2008. Leaf samples were handled with nitrile gloves at all stages. The leaf samples were composited by species, dried (60C) and ground (mortar and pestle) before analysis. Total biogenic silicon (SiO2) content was measured for every second year using a single-step chemical extraction. Measurements were aimed to estimate annual Si uptake, and standing Si stocks in living biomass for northern hardwood forest. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.

opencc-zeroAug 2020View details →

Datasets - Evolutionary history, not ecogeographic rules, explains size variation of tropical insects along elevational gradients

One of the best-known biogeographic rules for ectotherms is the temperature-size rule, which asserts that ectotherms produce smaller adults at warmer temperatures. Although this is often true, it has become clear that there is no single process behind the pattern and many exceptions to the rule. To disentangle such complex temperature-size relationships, individual clades must be examined at ecological and evolutionary scales. We examined temperature-size relationships for 2106 individuals from 64 populations and 40 species of Cephaloleia rolled-leaf beetles (Chrysomelidae; Cassidinae) occurring along two tropical elevational gradientss: Barva and the Talamanca Cordillera in Costa Rica, Central America. We tested whether the temperature-size rule applied to interspecific elevational assemblages, intraspecific elevational populations, or different rearing temperatures for individual populations. At the interspecific scale, evolutionary history, rather than elevation, explains body size. At the intraspecific scale, only one of seven species followed the temperature-size rule across elevations. When larvae were reared at different temperatures, only one of five populations followed the temperature-size rule. Most populations grew to a fixed size regardless of temperature. Size in Cephaloleia beetles is constrained by their evolutionary history and responds to factors that rarely correlate with temperature. As temperature increases, ectotherms will not universally shrink, but determining if and why their size will change will require further investigation. Here we provide the following datasets used to determine effects of temperature on insect body size at population and community levels: Supplement S1. Body length for 2106 individuals representing 64 populations from 40 species of Cephaloleia rolled-leaf beetle along the Barva and Talamanca elevational gradients, Costa Rica. Supplement S2. Intraspecific differences in length for 798 individuals from seven Cephaloleia species present at multiple life zone. Supplement S3. Effects of developmental temperatures on Cephaloleia adult size in 968 individuals from four species and five populations reared in the laboratory at temperatures between 10 and 35 °C.

opencc-zeroAug 2020View details →

Environmental determinants of leaf-litter ant community composition along an elevational gradient

Ant communities are extremely diverse and provide a wide variety of ecological functions in tropical forests. Here we investigated the abiotic factors driving ant composition turnover across an elevational gradient at Mont Itoupé, French Guiana. Mont Itoupé is an isolated mountain whose top is covered by cloud forests, a biogeographical rarity that is likely to be threatened according to climate change scenarios in the region. We examined the influence of six soil, climatic and LiDAR-derived vegetation structure variables on leaf-litter ant assembly (267 species) across nine 0.12-ha plots disposed at three elevations (ca. 400, 600 and 800m asl). We tested (a) whether species co-occurring within a same plot or a same elevation were more similar in terms of taxonomic, functional and phylogenetic composition, than species from different plots/elevations, and (b) which environmental variables significantly explained compositional turnover among plots. We found that the distribution of species and traits of ant communities along the elevational gradient was significantly explained by a turnover of environmental conditions, particularly in soil phosphorus and sand content, canopy height and mean annual relative humidity of soil. Our results shed light on the role exerted by environmental filtering in shaping ant community assembly in tropical forests. Identifying the environmental determinants of ant species distribution along tropical elevational gradients could help predicting the future impacts of global warming on biodiversity organization in vulnerable environments such as cloud forests.

opencc-zeroSep 2020View details →

Speciation and gene flow across an elevational gradient in New Guinea kingfishers

Closely related species with parapatric elevational ranges are ubiquitous in tropical mountains worldwide. The gradient speciation hypothesis proposes that these series are the result of in situ ecological speciation driven by divergent selection across elevation. Direct tests of this scenario have been hampered by the difficulty inferring the geographic arrangement of populations at the time of divergence. In cichlids, sticklebacks, and Timema stick insects, support for ecological speciation driven by other selective pressures has come from demonstrating parallel speciation, where divergence proceeds independently across replicated environmental gradients. Here, we take advantage of the unique geography of the island of New Guinea to test for parallel gradient speciation in replicated populations of Syma kingfishers that show extremely subtle differentiation across elevation and between historically isolated mountain ranges. We find that currently described high elevation and low elevation species have reciprocally monophyletic gene trees and form nuclear DNA clusters, rejecting this hypothesis. However, demographic modeling suggests selection has likely maintained species boundaries in the face of gene flow following secondary contact. We compile evidence from the published literature to show that while in situ gradient speciation in labile organisms such as birds appears rare, divergent selection and post-speciation gene flow may be an underappreciated force in the origin of elevational series and tropical beta diversity along mountain slopes.

opencc-zeroOct 2021View details →

The interacting effect of habitat amount, habitat diversity and fragmentation on insect diversity along elevational gradients.

Aim: Elevational gradients are a useful approach to evaluate how environmental factors affect animal diversity. Decades of studies on the elevation-diversity gradient have revealed that this gradient varies greatly with taxa and geographic regions. One potential explanation for this may be the dependence of the relationship on landscape features. We explore the impact of fragmentation, habitat diversity and habitat amount on insect diversity (alpha and beta) and abundance along elevational gradients. We hypothesize that insect diversity and abundance will relate negatively with elevation, but positively with these landscape features. We also hypothesize that landscape features will interact in a way that the positive effect of a given variable on insect diversity may be offset by the others. Location: Reunion Island (Indian Ocean) Taxon: The insect order thrips (Thysanoptera) Methods: Insects were sampled along replicated elevational gradients, and at each sampling plot landscape features and abiotic variables were estimated within buffers surrounding the site. Insect alpha diversity was estimated using abundance-based rarefaction methods, whereas beta diversity was estimated calculating the "local contributions to beta diversity" metric. The effect of elevation, rainfall, landscape features and their interactions was assessed on insect alpha and beta diversity and abundance during two consecutive seasons using linear mixed effects models. Results: We found that thrips alpha and beta diversity was negatively related with elevation, but the relationship varied between seasons and rainfall regimes. Among the different landscape features considered, we found that habitat amount had the strongest effect on diversity. The effect of habitat amount on diversity, however, was offset in areas of low habitat (or land cover) diversity. Main conclusions: Generalizing the factors that underlie the elevation diversity gradient has become a cornerstone in ecological theory because it can help to understand the impact of human activities on diversity. Here we show that taking landscape information into account may help to fulfil this objective because landscape effects co-vary with elevation with often intricate consequences for diversity.

opencc-zeroDec 2020View details →

The timing of leaf senescence relates to flowering phenology and functional traits in 17 herbaceous species along elevational gradients

1. Leaf senescence is a major event in a plant's life history as autumn marks the end of the growing season. The optimal timing of leaf senescence is crucial to both, minimize risks of low temperature events and maximize carbon gain during the growing season. As abiotic conditions are currently changing at unprecedented rates, it is important to study how leaf senescence of different species is responding to these changes in order to forecast future growing season length and carbon sequestration potentials. In contrast to flowering phenology, data on autumn events is scarce and even more so for herbaceous than for woody plants, thus more information on this phenological stage is urgently needed. 2. We studied leaf senescence of 632 populations from 17 herbaceous species located along elevational gradients. We focussed on the beginning (5% of the population senesce, LS5) and peak (50% senesce, LS50) of leaf senescence. To see whether we can predict species-specific changes, we studied the link between LS5 and LS50 and flowering phenology as well as leaf functional traits related to plant performance. We looked at first and last flowering day and flowering duration as well as the traits specific leaf area, leaf dry matter content, area based leaf nitrogen and carbon content, carbon isotope discrimination (Δ13C), and the stomatal pore area index. 3. We found species-specific slopes of the beginning of leaf senescence along the elevational gradient. The peak of leaf senescence was uniformly delayed with increasing elevation across all species. Flowering phenology as well as leaf functional traits had a close relationship with leaf senescence and thus can be used to forecast species-specific responses to changes in abiotic conditions. High SLA and high leaf nitrogen were related to earlier senescence while high LDMC, high Δ13C and high SPI to later senescence. 4. Synthesis: The link between senescence, flowering phenology and plant functional traits will help to fine-tune predictions of future growing season length and ecosystem function. To date, most analyses are based on spring phenology and traits, for which data is more abundant than data on autumn senescence.

opencc-zeroDec 2017View details →

Data from: Local environment, not local adaptation, drives leaf-out phenology in common gardens along an elevational gradient in Acadia National Park, Maine

PREMISE OF THE STUDY: Climate-driven changes in phenology are substantially affecting ecological relationships and ecosystem processes. The role of variation among species has received particular attention; for example, variation among species' phenological responses to climate can disrupt trophic interactions and can influence plant performance. Variation within species in phenological responses to climate, however, has received much less attention, despite its potential role in ecological interactions and local adaptation to climate change. METHODS: We constructed three common gardens across an elevation gradient on Cadillac Mountain in Acadia National Park, Maine to test population-level responses in leaf-out phenology in a reciprocal transplant experiment. The experiment included three native species: low bush blueberry (Vaccinium angustifolium), sheep's laurel (Kalmia angustifolia), and three-toothed cinquefoil (Sibbaldiopsis tridentata). KEY RESULTS: Evidence for local adaptation of phenological response to temperature varied among the species, but was weak for all three. Rather, variation in phenological response to temperature appeared to be driven by local microclimate at each garden site and year-to-year variation in temperature. CONCLUSIONS: Population-level adaptations in leaf-out phenology appear to be relatively unimportant for these species in Acadia National Park, perhaps a reflection of strong genetic mixing across elevations, or weak differences in selection on phenological response to spring temperatures at different elevations. These results concur with other observational data in Acadia and highlight the utility of experimental approaches to understand the importance of annual and local site variation in affecting phenology both among and within plant species.

opencc-zeroDec 2017View details →

Data from: Breeding season length and nest mortality drive cryptic life history variation in Dark-eyed Juncos (Junco hyemalis) breeding across a montane elevation gradient

The manner in which individual life history traits respond to the environment and to each other, and how these traits combine to form overall patterns of life history variation, remains poorly characterized in wild populations. We monitored breeding Dark-eyed Juncos (Junco hyemalis) across a 700-m elevational range. We compared breeding season length, temporal patterns of breeding activity, adult body size, clutch size, brood size, nestling quality, and nest mortality among elevations. We also compared environmental measures across the studied elevations to determine whether abiotic factors explained life history trait variation. We used 12 microsatellite loci to test for genetic differentiation in populations at different elevations. Finally, we constructed a computer simulation to evaluate the combined effects of observed variation in life history traits. We found differences among elevations in breeding season length and in patterns of reproductive timing, which did not match each other and which were not explained solely by abiotic factors. We found no differences among elevations in adult body size, clutch size, brood size, or nestling quality. Nest mortality increased significantly with elevation. Genetic differentiation was too low to define distinct subpopulations. The simulation suggested that differences in mortality, in combination with differences in breeding season length, contributed to substantial differences in reproductive success among elevations. Thus, although individual life history traits showed little evidence of variation in response to the environment or to each other and little genetic differentiation, variation in breeding season length and in nest mortality were potential drivers of substantial elevational variation in overall life history in this system. These results demonstrate that individual life history traits may vary substantially in their patterns of variation, and that some life history traits may have disproportionate effects on overall life history.

opencc-zeroApr 2020View details →

Data from: Cold adaptation across the elevation gradient in an alpine butterfly species complex

1. Temperature acts as a major factor on the timing of activity and behaviour in butterflies, and it might represent a key driver of butterfly diversification along elevation gradients. Under this hypothesis, local adaptation should be found along the elevation gradient, with butterflies from high elevation populations able to remain active at lower ambient temperature than those from low elevation. 2. We recorded the warming-up rate and the thoracic temperature at take-off of 123 individuals of the Alpine butterfly species complex Coenonympha arcania - C. macromma - C. gardetta in controlled conditions. 3. Warming-up rate increased with elevation within C. arcania: high elevation males of C. arcania were able to warm-up more quickly, as compared to low elevation ones. 4. High elevation C. gardetta had a darker underwing pattern than low elevation ones. This high-elevation species was significantly smaller (lower weight and wing surface) than the two other species, and had a faster warming up rate. 5. Our results suggest that the ability to warm-up quickly and to take-flight at a high body temperature evolved adaptively in the high-altitude C. gardetta, and that low temperature at high altitude may explain the absence there of C. arcania, while the hybrid nature of C. macromma is probably the explanation of its elevation overlap with both other species, and its local replacement of C. gardetta.

opencc-zeroJun 2021View details →

Phenotypic and genomic diversification with isolation by environment along elevational gradients in a neotropical treefrog

Understanding how geographic and environmental heterogeneity drive local patterns of genetic variation is a major goal of ecological genomics and a key question in evolutionary biology. The tropical Andes and inter-Andean valleys are shaped by markedly heterogeneous landscapes, where species experience strong selective processes. We examined genome-wide SNP data together with behavioral and ecological traits (mating calls and body size) known to contribute to genetic isolation in anurans in the emerald-eyed treefrog, Boana platanera, distributed across an environmental gradient in Central Colombia (northern South America). We analyzed the relationships between environmentally (temperature and precipitation) associated genetic and phenotypic differentiation and the potential drivers of isolation by environment along an elevation gradient. We identified candidate SNPs associated with temperature and body size, which follow a clinal pattern of genome-wide differentiation tightly coupled with phenotypic variation: as elevation increases, B. platanera exhibits larger body size and longer call duration with more pulses but lower pulse rate and frequency. Thus, the environmental landscape has rendered a scenario where isolation by environment and candidate loci show phenotypic divergence in this tropical frog along an elevation gradient in the Colombian Andes. Our study sets the basis for evaluating the role of temperature in the genetic structure and local adaptation in tropical treefrogs and its putative effect on life cycle (embryos, tadpoles, adults) along elevation gradients.

zenodo36/100

Parallel Body Shape Divergence in the Neotropical Fish Genus Rhoadsia (Teleostei: Characidae) Along Elevational Gradients of the Western Slopes of the Ecuadorian Andes

TPS files for geometric morphometric analysis of body shape data of Rhoadsia spp. (Teleostei: Characidae) collected in western Ecuador.

opencc-by-4.0May 2017View details →

zenodo36/100

Parallel Body Shape Divergence in the Neotropical Fish Genus Rhoadsia (Teleostei: Characidae) Along Elevational Gradients of the Western Slopes of the Ecuadorian Andes

Morphological data collected from specimens of Rhoadsia spp. (Teleostei: Characidae) in western Ecuador. Excel file with individual standard length (SL), body depth (BD), size-adjusted fineness ratio (Adj_FR), and size-adjusted canonical variates analysis scores on axes 1 and 2 (Adj_CV1, Adj_CV2).

opencc-by-4.0May 2017View details →

opencc-zeroNov 2023View details →

Local and regional diversity of frog communities along an extensive rainforest elevation gradient in Papua New Guinea

Rainforests on high tropical mountains are globally important species diversity hotspots. We studied amphibians along an extensive rainforest elevation gradient on Mt. Wilhelm (4,509 m) in Papua New Guinea. We established eight sites at 500 m elevation increments between 200 and 3,700 m a.s.l. and related their community composition to the known species pool of New Guinea island. We recorded 3,390 frogs from 55 species, which is three times more species than at any local community along the elevation gradient. Species diversity peaked at 1,700 m a.s.l. for Mt. Wilhelm communities, and at 500–1,100 m a.s.l. in the broader New Guinea fauna, probably reflecting increasing speciation and decreasing dispersal rates with increasing elevation. The beta diversity between frog communities was high and increased with increasing elevation. The change in frog community composition across 500 m elevation corresponded to the change over 200 km distance within lowland forests. A majority of frog species were distributed over narrow <500 m elevational ranges, at Mt Wilhelm and the New Guinea fauna more broadly. We did not detect Rapoport's pattern of wider elevation range for species at higher elevations than for lowland species, for Mt. Wilhelm communities or the New Guinea fauna. The high beta diversity patterns along elevation gradients generated by rapid species turnover with narrow elevation ranges make frog communities vulnerable to change in the environment, including climate change.

opencc-zeroDec 2023View details →

Abundance, biomass and species richness of macrozoobenthos along an intertidal elevation gradient

Ecology aims to comprehend species distribution and its interaction with environmental factors, from global to local scales. While global environmental changes affect marine biodiversity, understanding the drivers at smaller scales remains crucial. Tidal flats can be found on most of the world's coastlines and are particularly vulnerable to anthropogenic disturbances. They are important transient ecosystems between terrestrial and marine ecosystems and their biodiversity provides important ecosystem services. Owing to this unique position at the terrestrial-marine transition, strong environmental gradients of elevation, sediment composition and food availability prevail. The data set contains information on macrozoobenthos abundance, biomass and community composition and abiotic and biotic environmental factors at a regional and local level at back barrier tidal flats of three East-Frisian islands in Germany. As environmental data elevation, mud content in the sediment, total organic carbon (TOC), porewater nutrients and Chl a are included.