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opencc-zeroMar 2022View details →

The living heart: climate gradients predict desert mountain endemism

Mountain regions are centres of biodiversity endemism at a global scale but the role of arid- zone mountain ranges in shaping biodiversity patterns is poorly understood. Focusing on three guilds of taxa from a desert upland refugium in Australia, we sought to determine: 1) the relative extent to which climate, terrain or geological substrate predict endemism, and 2) whether patterns of endemism are complimentary across broad taxonomic guilds. We mapped regional endemism for plants, land snails and vertebrates using combined Species Distribution Models (SDMs) for all endemic taxa (n=82). We then modelled predictors of endemism using Generalised Additive Models (GAMs) and geology, terrain and climate variables. We tested for the presence of inter- and intraguild hotspots of endemism. Many individual plant and land snail taxa were tightly linked with geology, corresponding to small distributions. Conversely, most vertebrate taxa were not constrained to specific geological substrates and occurred over larger areas. However, across all three guilds, climate was the strongest predictor of regional endemism, particularly for plants wherein discrete hotspots of endemism were buffered from extreme summer temperatures. Land snail and vertebrate endemism peaked in areas with the highest precipitation in the driest times of the year. Hotspots of endemism within each guild poorly predicted endemism in other guilds. We found an overarching signal that climatic gradients play a dominant role in the persistence of endemic taxa in an arid-zone mountain range system. An association with higher rainfall and cooler temperatures indicates that continuing trends towards hotter and drier climates may lead to range contractions in this, and potentially other, arid-zone mountain biotas. Contrasting patterns of endemism across guilds highlight the need to couple comprehensive regional planning for the protection of climate refugia, with targeted management of more localised and habitat specialist taxa.

opencc-zeroMar 2022View details →

Independent variation of avian sensitivity to climate change and trait-based adaptive capacity along a tropical elevational gradient

Aim: How species respond to climate change is influenced by their sensitivity to climatic conditions (i.e., their climatic niche) and aspects of their adaptive capacity (e.g., their dispersal ability, ecological niche). To date, it is largely unknown whether and how species' sensitivity to climate change and their adaptive capacity covary. However, understanding this relationship is important to predict the potential consequences of a changing climate for species assemblages. Here, we test how species' sensitivity to climate change and trait-based measures of their ecological adaptive capacity (i) vary along a broad elevational gradient and (ii) covary across a large number of bird species. Location: A Neotropical elevational gradient (300 - 3600 m.a.s.l.) in the Manú biosphere reserve, south‐east Peru. Methods: We focus on 215 frugivorous bird species along a Neotropical elevational gradient. We approximate species' sensitivity to climate change by their climatic niche breadth, based on species occurrences across South America and bioclimatic variables. In addition, we use a trait-based approach to estimate the dispersal ability of species (approximated by their wing pointedness), their dietary niche breadth (approximated by bill width), and their habitat niche breadth (the number of used habitat classes). Results: We found that (i) species' climatic niche breadth increased with elevation, while their trait-based dispersal ability and dietary niche breadth decreased with elevation, and (ii) sensitivity to climate change and trait-based adaptive capacity were not related across species. Main conclusions: These results suggest different mechanisms of how species in lowland and highland assemblages might respond to climate change. The independent variation of species' sensitivity to climate change and their trait-based adaptive capacity suggests that accounting for both dimensions will improve assessments of species' susceptibility to climate change and potential impacts of climate change on diverse species assemblages.

opencc-zeroMar 2022View details →

Metabolite profiling of the social spider Stegodyphus dumicola along a climate gradient

Animals experience climatic variation in their natural habitats, which may lead to variation in phenotypic responses among populations through local adaptation or phenotypic plasticity. In ectotherm arthropods, the expression of thermoprotective metabolites such as free amino acids, sugars, and polyols, in response to temperature stress, may facilitate temperature tolerance by regulating cellular homeostasis. If populations experience differences in temperatures, individuals may exhibit population-specific metabolite profiles through differential accumulation of metabolites that facilitate thermal tolerance. Such thermoprotective metabolites may originate from the animals themselves or from their associated microbiome, and hence microbial symbionts may contribute to shape the thermal niche of their host. The social spider Stegodyphus dumicola has extremely low genetic diversity, yet it occupies a relatively broad temperature range occurring across multiple climate zones in Southern Africa. We investigated whether the metabolome, including thermoprotective metabolites, differs between populations, and whether population genetic structure or the spider microbiome may explain potential differences. To address these questions, we assessed metabolite profiles, phylogenetic relationships, and microbiomes in three natural populations along a temperature gradient. The spider microbiomes in three genetically distinct populations of S. dumicola showed no significant population-specific pattern, and none of its dominating genera (Borrelia, Diplorickettsia, and Mycoplasma) are known to facilitate thermal tolerance in hosts. These results do not support a role of the microbiome in shaping the thermal niche of S. dumicola. Metabolite profiles of the three spider populations were significantly different. The variation was driven by multiple metabolites that can be linked to temperature stress (e.g. lactate, succinate or xanthine) and thermal tolerance (e.g. polyols, trehalose, or glycerol): these metabolites had higher relative abundance in spiders from the hottest geographic region. These distinct metabolite profiles are consistent with a potential role of the metabolome in temperature response.

opencc-zeroMay 2022View details →

Phylogenetic relatedness of food plants reveals highest insect herbivore specialization at intermediate temperatures along a broad climatic gradient

Phytophagous insects differ in their degree of specialisation, biased by resource availability. The composition and richness of herbivore and plant assemblages change along climatic gradients, but knowledge about associated shifts in specialisation is scarce and lacks controlling for abundance and phylogeny of interaction partners. Thus, we aimed to test whether the specialisation of herbivores in insect- plant – interaction networks decreases towards cold habitats as predicted by the 'altitude niche-breadth hypothesis' to forecast possible consequences of interaction rewiring under climate change. We used a non-invasive, standardized metabarcoding approach to reconstruct dietary relationships of Orthoptera species as a major insect herbivore taxon along a broad temperature gradient (~12 °C) in southern Germany. Based on orthopteran surveys, direct feeding observations in field, collection of faecal pellets from > 3,000 individuals of 54 species, and parallel vegetation surveys on 41 grassland sites, we quantified plant resource availability and its use by herbivores. Faecal samples were pooled for each species per site.

opencc-zeroJun 2022View details →

Why do parasites exhibit reverse latitudinal diversity gradients? Testing the roles of host diversity, habitat, and climate

Aim: The latitudinal diversity gradient (LDG) – in which species richness decreases from the equator toward the poles – is among the most fundamental distributional patterns in ecology. Despite the expectation that the diversity of parasites tracks that of their hosts, available evidence suggests that many parasites exhibit reverse latitudinal gradients or no pattern, yet the rarity of large-scale datasets on host-parasite interactions calls into question the robustness of such trends. Here, we collected parasitological data from a host group of conservation importance – lentic-breeding amphibians – to characterize the form and direction of relationships among latitude, parasite richness, and parasite load. Location: The contiguous USA. Time period: 2000 to 2014. Major taxa studied: Lentic-breeding frogs and toads and their helminth parasites. Methods: We collected information on parasite richness and infection load for 846 amphibian populations representing 31 species. We combined these data with environmental and biological data to test for LDGs and potential mechanisms. Results: Both parasite richness and abundance increased across 20 degrees of latitude – a reverse LDG. For parasite richness, this pattern was partially explained by latitudinal increases in wetland area, landcover diversity, and the richness of waterbirds – which function as definitive hosts for many amphibian parasites. Host body size also correlated positively with latitude and helminth richness, potentially reflecting increased habitat availability, greater host longevity, or a persistent phylogenetic signal. Parasite abundance associated positively with wetland area and landcover diversity, but negatively with amphibian taxonomic richness. Longitude exhibited non-linear relationships with parasite abundance and richness, which we suggest stem from large-scale variation in host availability (e.g., migratory bird flyways). Main conclusions: With growing interest in the distribution of parasites and pathogens, these results highlight the importance of inverse latitudinal gradients while emphasizing the explanatory influence of host body size, habitat availability, and host diversity.

opencc-zeroAug 2022View details →

New tree‐level temperature response curves document sensitivity of tree growth to high temperatures across a US‐wide climatic gradient

Temperature is a key climate indicator, whose distribution is expected to shift right in a warming world. However, the high temperature tolerance of trees is less widely understood than their drought tolerance, especially when it comes to sub-lethal impacts of temperature on tree growth. I use a large data set of annual tree ring widths, combined with a flexible degree-day model, to estimate the relationship between temperature and tree radial growth. I find that tree radial growth responds non-linearly to temperature across many ecoregions of the US: across temperate and/or dry ecoregions, spring-summer temperature increases are beneficial or mostly neutral for tree growth up to around 25-30°C in humid climates and 10-15°C in dry climates, beyond which temperature increases suppress growth. Thirty additional degree-days above the optimal temperature breakpoint lead to an average decrease in tree ring width of around 1-5%, depending on ecoregions, seasons, and inclusion or exclusion of temperature-mediated drought impacts. High temperatures have legacy effects across a 5-year horizon in dry ecoregions, but none in the temperate-humid South-East or among temperature-sensitive trees. I find limited evidence that trees acclimatize to high temperatures within their lifetime: local variation in exposure to high temperatures, which stems from local variation in the timing of tree birth, does not significantly impact the response to high temperatures, although temperature-sensitive trees acquire some heightened sensitivity from early exposure. I also find some evidence that trees adapt to high temperatures in the long-run: across humid ecoregions of the US, high temperatures are 40% less harmful to tree growth, where their average incidence is one standard deviation above average. Overall, these results highlight the strength of a new methodology which, applied to representative tree ring data, could contribute to predicting forest carbon uptake potential and composition under global change.

opencc-zeroDec 2014View details →

Data from: Small-mammal isotope ecology tracks climate and vegetation gradients across western North America

Stable carbon, nitrogen, hydrogen and oxygen isotopes have been used to infer aspects of species ecology and environment in both modern ecosystems and the fossil record. Compared to large mammals, stable isotopic studies of small-mammal ecology are limited; however, high species and ecological diversity within small mammals presents several advantages for quantifying resource use and organism–environment interactions using stable isotopes over various spatial and temporal scales. We analyzed the isotopic composition of hair from two heteromyid rodent species, Dipodomys ordii and Perognathus parvus, from localities across western North America in order to characterize dietary variation in relation to vegetation and climatic gradients. Significant correlations between the carbon isotopic composition (δ13C) of these species and several climatic variables imply that seasonal temperature and precipitation control the composition and distribution of dietary resources (grass seeds). Our results also suggest a moisture influence on the nitrogen isotopic composition (δ15N) of heteromyid diets. Population- and species-level variation in δ13C and δ15N values record fine-scale habitat heterogeneity and significant differences in resource use between species. Using classification and regression-tree techniques, we modeled the geographic variation in heteromyid δ13Cdiet values based on 10 climatic variables and generated an isotope landscape model ('isoscape'). The isoscape predictions for δ13Cdiet differ from expectations based on observed C4 distributions and instead indicate that D. ordii and P. parvus record seasonally abundant grass resources, with additional model deviations potentially attributed to geographic variation in dietary selection. The oxygen and hydrogen isotopic composition of D. ordii is enriched relative to local meteoric water and suggests that individuals rely on highly evaporated water sources, such as seed moisture. Based on the climatic influences on vegetation and diet documented in this study, the isotopic composition of small mammals has high potential for recording ecological responses to environmental changes over short and long time scales.

FIGURE 2 in Phenotypical variation and taxonomic correlates of five closely related Andean species of Poa (Poaceae) along geographic and climatic gradients

FIGURE 2. Plots of PC1 × PC2 and PC1 × PC3 from principal components analysis (PCA) of all specimens in the study. ANFA: P. anfamensis; JUJ: P. jujuyensis; LILL: P. lilloi; PARV: P. parviceps; SCAB: P. scaberula.

FIGURE 1 in Phenotypical variation and taxonomic correlates of five closely related Andean species of Poa (Poaceae) along geographic and climatic gradients

FIGURE 1. DIVA-GIS map of environmental variables and 150 collection sites of Poa specimens from the Andes in South American. A. Elevation. B. Annual mean precipitation. C. Annual mean temperature. D. Annual maximum temperature. E. Annual minimum temperature. Symbols for the Poa species are described in E.

FIGURE 4 in Phenotypical variation and taxonomic correlates of five closely related Andean species of Poa (Poaceae) along geographic and climatic gradients

FIGURE 4. Box plots representing the mean, median, interquartile range, adjacent values (lines), and outliers (dots) of quantitative characters in P. lilloi and P. scaberula.

FIGURE 3 in Phenotypical variation and taxonomic correlates of five closely related Andean species of Poa (Poaceae) along geographic and climatic gradients

FIGURE 3. Plot of discriminant analysis (DA) along the first two discriminant axes obtained from all specimens pertaining to a priori defined species. ANFA: P. anfamensis; JUJ: P. jujuyensis; LILL: P. lilloi; PARV: P. parviceps; SCAB: P. scaberula.

opencc-zeroAug 2021View details →

Data from: Climate and vegetation structure shape ant communities along elevational gradients on the Colorado Plateau

Aim: Terrestrial animal communities are largely shaped by vegetation and climate. With climate also shaping vegetation, can we attribute animal patterns solely to climate? To understand this, we compare the relative and interactive effects of climate and vegetation on an animal community. Our study observes ant community changes along climatic gradients (i.e. elevational gradients) within different habitat types (i.e. open and forest). We compare the explanatory powers and effect sizes of climate and vegetation variables on ant communities and describe what drives elevational distributions of ant species. Location: Colorado Plateau, southwestern United States Taxon: Formicidae Methods: We sampled ants and vegetation along two elevational gradients spanning 1132m with average annual temperature and precipitation differences of 5.7C° and 645 mm, respectively. Regression analysis and structural equation modeling was then used to test the relative effects of climate and vegetation variables on ant communities. Results: Climate variables had the strongest correlations and the largest effect sizes on ant communities, while vegetation composition, richness, and primary productivity were relatively small. Precipitation was the strongest predictor for most ant community metrics. Ant richness and abundance had a negative relationship with precipitation in forested habitats, and positive in open habitats. Main conclusions: Our results show strong direct climate effects on ants with little or no effects of vegetation composition or primary productivity, but contrasting patterns between vegetation type (i.e. forested vs open) with precipitation. This indicates vegetation structure can modulate climate responses of ant communities. Our study demonstrates climate-animal relationships may vary among vegetation types which can impact both findings from elevational studies and how communities will react to changes in climate.

opencc-by-4.0Oct 2021View details →

Long-term changes in flowering synchrony reflect climatic changes across an elevational gradient

These are the data with the accompanying R code used in the article "Long-term changes in flowering synchrony reflect climatic changes across an elevational gradient", by Fisogni A, de Manincor N, Bertelsen CD, and Rafferty NE. We provide the raw data on flowering phenology, temperature and precipitation data in the study area, and overlap estimates used to evaluate temporal changes within and between elevations and their relationship with changing climatic variables. Data are .txt files with tab separated values. The raw dataset was created by C. David Bertelsen from field observations performed from 1984 to 2019 along a fixed transect in the Santa Catalina Mountains, Arizona, USA.

opencc-by-4.0Nov 2022View details →

Dataset for Salinity Gradient Solar Pond under different Climatic Conditions and Soil Conditions

Salinity Gradient Solar Pond as a two-dimensional model with an internal heat source. The differential equations in this model are solved using the finite difference technique in MATLAB software. The attached dataset includes the soil conditions, the climate of the particular site, the thickness of the solar pond layers, the depth of the water table.

opencc-zeroJan 2023View details →

Staying in situ or shifting range under ongoing climate change: A case of an endemic herb in the Himalaya-Hengduan Mountains across elevational gradients

Aim: How species respond to ongoing climate change has been a hot research topic, especially with the controversy in shifting range (movement) or persisting in local habitat (in situ) as the primary response. Assessing the relative roles of range shifts, phenotypic plasticity and genetic adaptation helps us predict the evolutionary fate of species. We aim to explore the evolutionary strategies of plants under climate change from a keystone herb in alpine ecosystems, Mirabilis himalaica, along its elevational gradient. Location: Himalaya-Hengduan Mountains, China. Methods: We combined evidence from population genomics and ecological data in both space and time to investigate the state of "staying" or "moving". We identified migration events by assessing historical and contemporary gene flow, and changes in species distribution. Morphological variation was compared by measuring five traits using specimen data. Moreover, we explored climate-driven genetic variation and local selection regimes acting on populations in the alpine landscape along an elevational gradient. Results: Our results argue that staying in situ by morphological variation and local genetic evolution rather than range shifting plays an important role in M. himalaica response to climate change. We first found trace evidence of upward or climatic-driven shifting along an elevational gradient, although asymmetric gene flow was restricted within microenvironments of mid-elevational populations. Furthermore, morphological variation comparisons revealed clinal variation, as resource allocation showed a declining pattern in vegetative growth but increased reproductive growth with increasing elevation. Outlier tests and environment association analyses indicated adaptative loci primarily related to thermal-driven selection and continuous adaptations to high elevation in the Himalaya-Hengduan Mountains. Main conclusions: Our findings show M. himalaica may persist in local habitats rather than shifting range under climate change, exhibiting a low risk of genomic vulnerability in current habitats. This study has important implications for improving our understanding of the evolutionary response in alpine plants to climate change.

opencc-zeroAug 2023View details →

Use climatic space-for-time substitutions with care: not only climate, but also local environment affect performance of the key forest species bilberry along elevation gradient

An urgent aim of ecology is to understand how key species relate to climatic and environmental variation, to better predict their prospects under future climate change. The abundant dwarf shrub bilberry (Vaccinium myrtillus L.) has caught particular interest due to its uphill expansion into alpine areas. Species' performance under changing climate has been widely studied using the climatic space-for-time approach along elevation gradients, but potentially confounding, local environmental variables that vary along elevation gradients have rarely been considered. In this study, performed in ten sites along an elevation gradient (200–875 m) in W Norway, we recorded species composition and bilberry performance, both vegetative (ramet size and cover) and reproductive (berry and seed production) properties, over one to four years. We disentangled effects of local environmental variables and between-year, climatic variation (precipitation and temperature), and identified shared and unique contributions of these variables by variation partitioning. We found bilberry ramet size, cover, and berry production to peak at intermediate elevations, whereas seed production increased upwards. The peaks were less pronounced in extreme (dry or cold) summers than in normal summers. Local environmental variables explained much variation in ramet size and cover, less in berry production, and showed no relation to seed production. Climatic variables explained more of the variation in berry and seed production than in ramet size and cover, with temperature relating to vegetative performance, and precipitation to reproductive performance. Bilberry's clonal growth and effective reproduction probably explain why the species persists in the forest and at the same time invades alpine areas. Our findings raise concerns about the appropriateness of the climatic space-for-time approach. We recommend including both climatic and local environmental variables in studies of variation along elevation gradients, and conclude that variation partitioning can be a useful supplement to other methods for analysing variation in plant performance.

publicOct 2024View details →

Influence of climate, weather and floral associations on pollinator community composition across an elevational gradient

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publicFeb 2016View details →

Data from: Species-wide patterns of DNA methylation variation in Quercus lobata and their association with climate gradients

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publicApr 2017View details →

Data from: Heterogeneous distributional responses to climate warming: evidence from rodents along a subtropical elevational gradient

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