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opencc-zeroDec 2018View details →

Data from: Deterministic tropical tree community turnover: evidence from patterns of functional beta diversity along an elevational gradient

Explaining the mechanisms that produce the enormous diversity within and between tropical tree communities is a pressing challenge for plant community ecologists. Mechanistic hypotheses range from niche-based deterministic to dispersal-based stochastic models. Strong tests of these hypotheses require detailed information regarding the functional strategies of species. A few tropical studies to date have examined trait dispersion within individual forest plots using species trait means in order to ask whether coexisting species tend to be more or less functionally similar than expected given a null model. The present work takes an alternative approach by: (i) explicitly incorporating population-level trait variability; and (ii) quantifying the functional beta diversity in a series of 15 tropical forest plots arrayed along an elevational gradient. The results show a strong pattern of decay in community functional similarity with elevation. These observed patterns of functional beta diversity are shown to be highly non-random and support a deterministic model of tropical tree community assembly and turnover.

opencc-zeroDec 2018View details →

Data from: Genetic basis of amphibian larval development along a latitudinal gradient: gene diversity, selection and links with phenotypic variation in transcription factor C/EBP-1

Ectotherm development rates often show adaptive divergence along climatic gradients, but the genetic basis for this variation is rarely studied. Here, we investigated the genetic basis for phenotypic variation in larval development in the moor frog Rana arvalis from five regions along a latitudinal gradient from Germany to northern Sweden. We focused on the C/EBP-1 gene, a transcription factor associated with larval development time. Allele frequencies at C/EBP-1 varied strongly among geographic regions. Overall, the distribution of alleles along the gradient was in concordance with the dual postglacial colonization routes into Scandinavia, with a large number of alleles exclusively present along the southern colonization route. Only three of 38 alleles were shared between the routes. Analysis of contemporary selection on C/EBP-1 showed divergent selection among the regions, likely reflecting adaptation to the local environmental conditions, although this was especially strong between southern and northern regions coinciding also with lineages from different colonization routes. Overall, the C/EBP-1 gene has historically been under purifying selection, however, two specific amino acid positions showed significant signals of positive selection. These positions showed divergence between southern and northern regions, and we suggest that they are functionally involved in the climatic adaptation of larval development. Using phenotypic data from a common garden experiment, we found evidence for specific C/EBP-1 alleles being correlated with larval development time, suggesting a functional role in adaptation of larval development to large-scale climatic variation.

opencc-zeroJun 2019View details →

Data from: Multi-trophic β-diversity mediates the effect of environmental gradients on the turnover of multiple ecosystem functions

1. Much effort has been devoted to better understanding the effects of environment and biodiversity on ecosystem functioning. However, few studies have moved beyond measuring biodiversity as species richness of a single group and/or focusing on a single ecosystem function. While there is a growing recognition that along environmental gradients, the compositional turnover of multiple trophic groups influences not only productivity but multiple ecosystem functions, we do not know yet which components of multi-trophic β-diversity influence which ecosystem functions. 2. Here, we captured the biodiversity found in soils using environmental DNA to study total soil multi-trophic β-diversity (between all taxa regardless of their trophic group association), horizontal β-diversities (β-diversities within trophic groups) and vertical β-diversity (β-diversity across trophic groups) along a 1000-m elevational gradient in the French Alps. Using path analyses, we quantified how these β-diversity components mediate the effects of environmental turnover on the turnover of multiple ecosystem functions (i.e. productivity, N-cycling, N-leaching) and overall multifunctionality. 3. While we found a strong direct effect of soil properties on the turnover of multiple ecosystem functions, we also found an indirect effect of climate and soil properties through multi-trophic β-diversity. More specifically, only total multi-trophic β-diversity and the horizontal β-diversity of saprophytic fungi were strongly related to the turnover of multifunctionality and, to a lower extent, the turnover of productivity and N-cycling. Our results suggest that decomposition processes and resulting nutrient availability are key to understand how ecosystem functions change along soil properties and climatic gradients in alpine ecosystems. 4. Beyond alpine systems, our study stresses the paramount importance of considering the mediating role of multi-trophic diversity in environmental change impacts on different ecosystem functions and their multifunctionality.

opencc-zeroSep 2019View details →

Data from: Ecological constraints coupled with deep-time habitat dynamics predict the latitudinal diversity gradient in reef fishes

We develop a spatially explicit model of diversification based on paleohabitat to explore the predictions of four major hypotheses potentially explaining the latitudinal diversity gradient (LDG), namely, the 'time-area', 'tropical niche conservatism', 'ecological limits' and 'evolutionary speed' hypotheses. We compare simulation outputs to observed diversity gradients in the global reef fish fauna. Our simulations show that these hypotheses are non-mutually exclusive and that their relative influence depends on the time scale considered. Indeed, simulations suggest that reef habitat dynamics produced the LDG during deep geological time, while ecological constraints shaped the modern LDG, with a strong influence of the reduction in the latitudinal extent of tropical reefs during the Neogene. Overall, this study illustrates how mechanistic models in ecology and evolution can provide a temporal and spatial understanding of the role of speciation, extinction and dispersal in generating contemporary biodiversity patterns.

opencc-zeroDec 2017View details →

Data from: Macroecology and macroevolution of the latitudinal diversity gradient in ants

The latitudinal diversity gradient—the tendency for more species to occur toward the equator—is the dominant pattern of life on Earth, yet the mechanisms responsible for it remain largely unexplained. Recently, the analysis of global data has led to advances in understanding, but these advances have been mostly limited to vertebrates and trees and have not provided consensus answers. Here, we synthesize large-scale geographic, phylogenetic, and fossil data for an exemplar invertebrate group—ants—and investigate whether the latitudinal diversity gradient arose due to higher rates of net diversification in the tropics, or due to a longer time period to accumulate diversity due to Earth's climatic history. We find that latitudinal affinity is highly conserved, temperate clades are young and clustered within tropical clades, and diversification rate shows no systematic variation with latitude. These results indicate that diversification time —and not rate— is the main driver of the diversity gradient in ants.

opencc-zeroDec 2013View details →

Data from: Large-scale fungal diversity assessment in the Andean Yungas forests reveals strong community turnover among forest types along an altitudinal gradient

The Yungas, a system of tropical and subtropical montane forests on the eastern slopes of the Andes, are extremely diverse and severely threatened by anthropogenic pressure and climate change. Previous mycological works focused on macrofungi (e.g., agarics, polypores) and mycorrhizae in Alnus acuminata forests, while fungal diversity in other parts of the Yungas has remained mostly unexplored. We carried out Ion Torrent sequencing of ITS2 rDNA from soil samples taken at 24 sites along the entire latitudinal extent of the Yungas in Argentina. The sampled sites represent the three altitudinal forest types: the piedmont (400–700 masl), montane (700–1500 masl), and montane cloud (1500–3000 masl) forests. The deep sequence data presented here (i.e. 4 108 126 quality-filtered sequences) indicate that fungal community composition correlates most strongly with elevation, with many fungi showing preference for a certain altitudinal forest type. For example, ectomycorrhizal and root endophytic fungi were most diverse in the montane cloud forests, particularly at sites dominated by Alnus acuminata, while the diversity values of various saprobic groups were highest at lower elevations. Despite the strong altitudinal community turnover, fungal diversity was comparable across the different zonal forest types. Besides elevation, soil pH, N, P, and organic matter contents correlated with fungal community structure as well, although most of these variables were co-correlated with elevation. Our data provide an unprecedented insight into the high diversity and spatial distribution of fungi in the Yungas forests.

opencc-zeroMay 2019View details →

Supplementary material 1 from: Cerrato C, Rocchia E, Brunetti M, Bionda R, Bassano B, Provenzale A, Bonelli S, Viterbi R (2019) Butterfly distribution along altitudinal gradients: temporal changes over a short time period. In: Mazzocchi MG, Capotondi L, Freppaz M, Lugliè A, Campanaro A (Eds) Italian Long-Term Ecological Research for understanding ecosystem diversity and functioning. Case studies from aquatic, terrestrial and transitional domains. Nature Conservation 34: 91-118. https://doi.org/10.3897/natureconservation.34.30728

Supplementary data

embargoedcc-by-4.0Dec 2024View details →

Arctic bryophyte and lichen diversity across microclimatic and competition gradients

Data collected as part of the project 'Arctic bryophyte and lichen diversity across microclimatic and competition gradients'. Plant data were collected following a standardised protocol in the field across an Arctic latitudinal gradient, including Latnjajaure, Sweden (2021), Longyearbyen, Svalbard (2022) and Disko Island, Greenland (2023). Surveying took place with the point-framing method in 0.5x0.5m plots, collecting a total of 30 hits per plot. In total, 110 plots were surveyed.  See metadata for a description of all data fields in the database.  First release of the data under embargo until the corresponding manuscript is published.

opencc-zeroJan 2022View details →

Data from: Taxonomic scale and community organization impact observed latitudinal gradients of parasite diversity

Aim: While most free-living taxa follow the latitudinal diversity gradient (LDG), or the trend of higher diversity at lower latitudes, we know little about how the diversity of parasitic taxa is distributed across latitudes. To better understand the macroecological patterns of parasite diversity, we sought to determine if: 1) helminths follow the traditional LDG; 2) taxonomic resolution impacts observed patterns; 3) latitudinal patterns are consistent across levels of community organization; and 4) helminth diversity is correlated with climate- and host- associated variables. Location: San Juan de Peñas Blancas, Costa Rica; Calnali, Hidalgo, Mexico; College Station, Texas, USA; Brownsville, Nebraska, USA; Winnipeg, Manitoba, Canada; Churchill, Manitoba, Canada Taxa: Rodentia: Cricetidae; Nematoda; Platyhelminthes Methods: We sampled parasites from hosts at field sites set approximately every 10 degrees in latitude. We evaluated the relationships between parasite species richness (of all helminths as well as nematodes, cestodes, and trematodes separately) and latitude, climate, and host mass at two levels of parasite community organization, the infracommunity and the component community, using generalized additive models. Results: Total helminth richness was significantly correlated with latitude, but the relationship was non-linear. Nematode, cestode, and trematode diversity were also significantly correlated with latitude, but the relationship differed between the levels of community organization and among the taxonomic groups. Climate and host-associated variables were significantly correlated with different parasite taxa, although the strength and size of the correlations varied among the groups. Main conclusions: There are complex associations between parasite richness and latitude, climate, and host traits, and community organization and taxonomic grouping affected the observed relationships. Climate has been implicated as an important factor in shaping LDG patterns and may similarly influence helminth diversity patterns. Overall, this work provides further support and exceptions to the LDG and stresses the importance of considering scale in ecological investigations.

opencc-zeroMar 2022View details →

Pollinator richness, pollination networks and diet adjustment along local and landscape gradients of resource diversity

Loss of habitats and native species, introduction of invasive species, and changing climate regimes lead to the homogenization of landscapes and communities, affecting the availability of habitats and resources for economically important guilds, such as pollinators. Understanding how pollinators and their interactions vary along resource diversity gradients at different scales may help to determine their adaptability to current diversity loss related to global change. We used data on 20 plant-pollinator communities along gradients of flower richness (local diversity) and landscape heterogeneity (landscape diversity) to understand how the diversity of resources at local and landscape scales affected: (1) wild pollinator abundance and richness (accounting also for honeybee abundance); (2) the structure of plant-pollinator networks; (3) the proportion of actively selected interactions (those not occurring by neutral processes) and (4) pollinator diet breadth and species' specialization in networks. Wild pollinator abundance was higher overall in flower-rich and heterogeneous habitats, while wild pollinator richness increased with flower richness (more strongly for beetles and wild bees) and decreased with honeybee abundance. Network specialization (H2'), modularity, and functional complementarity were all positively related to floral richness and landscape heterogeneity, indicating niche segregation as the diversity of resources increases at both scales. Flower richness also increased the proportion of actively selected interactions (especially for wild bees and flies), whereas landscape heterogeneity had a weak negative effect on this variable. Overall, network-level metrics responded to larger landscape scales than pollinator-level metrics did. Higher floral richness resulted in a wider taxonomic and functional diet for all the study guilds, while functional diet increased mainly for beetles. Despite this, specialization in networks (d') increased with flower richness for all the study guilds, because pollinator species fed on a narrower subset of plants as communities became richer in species. Our study indicates that pollinators are able to adapt their diet to resource changes at local and landscape scales. However, resource homogenization might lead to poor and generalist pollinator communities, where functionally specialized interactions are lost. This study highlights the importance of including different scales to understand the effects of global change on pollination service through changes in resource diversity.

opencc-by-4.0Jan 2024View details →

Figure 9 in Assessment of terrestrial snails' diversity and composition in six forests of west central - Morocco along an altitudinal gradient

Figure 9. Positions of stations on a nonlinear multidimensional scaling of abundance data (Bray-Curtis similiarity coefficient, 2D. Stress: 0.1395). Filled circles: Essaouira Dunes, diamonds: Tlat Lhanchane, squares: Ourika, filled squares: Azgour, filled triangles: Tamadout, circles: Oukaimeden.

opencc-zeroDec 2015View details →

Data from: Extinction as a driver of avian latitudinal diversity gradients

The role of historical factors in driving latitudinal diversity gradients is poorly understood. Here we used an updated global phylogeny of terrestrial birds to test the role of three key historical factors – speciation, extinction and dispersal rates – in generating latitudinal diversity gradients for eight major clades. We fit a model that allows speciation, extinction and dispersal rates to differ, both with latitude and between the New and Old World. Our results consistently support extinction (all clades had lowest extinction where species richness was highest) as a key driver of species richness gradients across each of eight major clades. In contrast, speciation and dispersal rates showed no consistent latitudinal patterns across replicate bird clades, and thus are unlikely to represent general underlying drivers of latitudinal diversity gradients.

opencc-zeroJun 2021View details →

Gradients of genetic diversity and differentiation across the distribution range of a Mediterranean coral: patterns, processes and conservation implications.

The aim of this study was to determine how historical and contemporary eco-evolutionary processes shape the patterns of genetic diversity and differentiation across species' distribution range remains an open question with strong conservation implications. Focusing on the orange stony coral, Astroides calycularis, we i) characterized the pattern of neutral genetic diversity across the distribution range; ii) gave insights into the underlying processes; and iii) discussed conservation implications with emphasis on a national park located on a hotspot of genetic diversity. Location: South Mediterranean Sea and Zembra National Park. We combined new data from 12 microsatellites in 13 populations located in the Centre and in the Western Periphery of the distribution range with a published dataset including 16 populations from the Western and Eastern Peripheries. We analysed the relationship among parameters of genetic diversity (He, Ar(g)) and structure (population-specific FST) and two measures of geographic peripherality. We compared two estimators of pairwise genetic structure (GST, DEST) across the distribution range. The evolutionary and demographic history of the populations following the Last Glacial Maximum was reconstructed using approximate Bayesian computations and Maximum Likelihood analyses. We inferred the contemporary connectivity among populations from Zembra National Park and with the neighbouring area of Cap Bon. We demonstrate a decrease of genetic diversity and an increase of genetic differentiation from the Centre to the Eastern and Western Peripheries of the distribution range. Populations from Zembra show the highest genetic diversity reported in the species. We identified a spillover effect towards Cap Bon. The patterns of genetic diversity and differentiation are most likely explained by "the postglacial range expansion hypothesis" rather than the "central-peripheral hypothesis". Enforcement of conservation measures should be considered to protect this genetic diversity pattern, in particular when considering the low effective population size inferred at many sites.

opencc-zeroJul 2021View details →

Effect of productivity on community size explains the latitudinal diversity gradient of South American small mammals

Although many studies have shown that species richness increases from high to low latitudes (the latitudinal diversity gradient), the mechanisms responsible for generating and maintaining higher species richness in the tropics remain intensely debated. Here, we investigate how the effects of temperature on speciation rates (kinetic effects) and the effects of productivity on community size (chemical effects) explain the latitudinal diversity gradient of South American small mammals. We implemented Bayesian models that integrate processes from the neutral and metabolic theories, comparing model predictions with empirical richness patterns. The neutral-metabolic model predicted the latitudinal richness gradient in South American small mammals. We found evidence that the effects of productivity on community size are more important for explaining differences in species richness than the effects of temperature on speciation rates. These results suggest that differences in species richness along latitudinal gradients are primarily regulated by the chemical effects of productivity on speciation-extinction dynamics.

Figure 6 from: Maveety S, Browne R, Erwin T (2011) Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera). ZooKeys 147: 651-666. https://doi.org/10.3897/zookeys.147.2047

Figure 6 - Non-Metric Multidimensional Scaling (NMDS) using the Bray Curtis Similarity Index for collections made actively (diamond) and passively (circle). Values for each altitude are grouped by ovals.

Figure 5 from: Maveety S, Browne R, Erwin T (2011) Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera). ZooKeys 147: 651-666. https://doi.org/10.3897/zookeys.147.2047

Figure 5 - Species accumulation curves when all altitudes and collection types (active or passive) are combined (n = 1924). Brackets represent 95% confidence intervals.

Figure 2 from: Maveety S, Browne R, Erwin T (2011) Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera). ZooKeys 147: 651-666. https://doi.org/10.3897/zookeys.147.2047

Figure 2 - Species accumulation curves for 5 diversity indices when all altitudes and collection types (active or passive) are combined (n = 1924).

Figure 4 from: Maveety S, Browne R, Erwin T (2011) Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera). ZooKeys 147: 651-666. https://doi.org/10.3897/zookeys.147.2047

Figure 4 - Percentage of rare species at five altitudinal sites. Black bars represent the taxonomic rarity index and gray bars represent the ecological rarity index (see text for definitions of rarity).

Figure 3 from: Maveety S, Browne R, Erwin T (2011) Carabidae diversity along an altitudinal gradient in a Peruvian cloud forest (Coleoptera). ZooKeys 147: 651-666. https://doi.org/10.3897/zookeys.147.2047

Figure 3 - Number of species at five altitudes when all altitudes and collection types (active or passive) are combined (n = 1924).