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openCC0Apr 2024View details →

Abiotic and biotic data collected from Spadra and Greenbriar Creeks in Clarksville, Arkansas in spring, 2024.

University of the Ozarks stream ecology students collected biotic (macroinvertebrate and fish community) and abiotic (temperature, pH, conductivity, dissolved oxygen, discharge) data in the spring 2024 semester. Macroinvertebrate data was collected using kick nets, D-nets, and visual inspection, and fish were collected using seine nets. Temperature is being logged in perpetuity with a HOBO, MX2201 data logger, and pH, conductivity, and dissolved oxygen were recorded using a YSI Quatro handheld multiparameter probe. River discharge was calculated manually using the surface float method, and a qualitative habitat assessment was conducted. This data package is a long-term, temporal, student-led data generation effort designed to be shared with the freshwater community.

openCC (other)May 2024View details →

Investigation of road salts and biotic stressors on freshwater wetland communities.

The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl2), at three environmentally relevant concentrations (150, 470, and 780 mg Cl−/L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Collectively, road salts and biotic stressors both can affect freshwater communities, but their effects are not interactive. The direct and indirect effects of road salts reported are important for management and conservation efforts given the salinization of freshwater systems following winter road maintenance.

openCC (other)Jun 2019View details →

Data for Context-dependent biotic interactions control plant abundance across altitudinal environmental gradients, 2014, 2016, Colorado, USA

Many biotic interactions influence community structure, yet most distribution models for plants have focused on plant competition or used only abiotic variables to predict plant abundance. Furthermore, biotic interactions are commonly context-dependent across abiotic gradients. For example, plant-plant interactions can grade from competition to facilitation over temperature gradients. We used a hierarchical Bayesian framework to predict the abundances of 12 plant species across a mountain landscape and test hypotheses on the context-dependency of biotic interactions over abiotic gradients. We combined field-based estimates of six biotic interactions (foliar herbivory and pathogen damage, fungal root colonization, fossorial mammal disturbance, plant cover, and plant diversity) with abiotic data on climate and soil depth, nutrients, and moisture. All biotic interactions were significantly context-dependent along temperature gradients. Results supported the stress gradient hypothesis: As abiotic stress increased, the strength or direction of the relationship between biotic variables and plant abundance generally switched from negative (suggesting suppressed plant abundance) to positive (suggesting facilitation/mutualism). For half of the species, plant cover was the best predictor of abundance, suggesting that the prior focus on plant-plant interactions is well-justified. Explicitly incorporating the context-dependency of biotic interactions generated novel hypotheses about drivers of plant abundance across abiotic gradients and may improve the accuracy of niche models.

openCC0Dec 2020View details →

The Combined Effects of Road Salt and Biotic Stressors on Amphibian Sex Ratios

Aquatic systems worldwide are threatened by the anthropogenic use of synthetic chemicals, including pesticides, pharmaceuticals, and road de‐icers. Exposure to contaminants can alter the behavior, morphology, and physiology of organisms if it occurs during sensitive life stages. For instance, past studies have documented feminization of male amphibians following herbicide exposure and skewed sex ratios among amphibian populations exposed to road salt. However, many of these studies lack the complexities found within natural environments, such as competition with conspecifics or threat of predation, which are also known to influence development. Thus, it is important to understand how anthropogenic and natural stressors interact to alter animal sex ratios. Given the growing concern of secondary salinization of freshwater systems, we exposed larval wood frogs (Rana sylvatica) to either road salt (sodium chloride [NaCl]) or an alternative salt mixture (NaCl, magnesium chloride [MgCl2], and potassium chloride [KCl]) at 3 concentrations (200, 600, and 1000 mg Cl−/L) crossed with 3 biotic stressors (no‐stressor control, competition, or predator cues) to examine their potentially interactive effects on sex. Exposure to biotic stressors and NaCl did not influence wood frog sex ratios. In contrast, tadpole exposure to the intermediate salt mixture concentration significantly reduced the proportion of female frogs. Future studies are needed to determine whether such changes in sex are widespread among sensitive species with complex life cycles, and to assess the consequences of sex ratio changes on long‐term population dynamics.

openCC (other)Nov 2020View details →

Biotic and abiotic composition of biological soil crusts in grassland and tarbush ecosystems at the Jornada Basin LTER site, 2017-2018

This data package contains data on biotic and abiotic composition of biological soil crusts at grassland and shrubland sites at the Jornada Basin LTER site. Biological soil crusts (BSCs) of three types, cyanolichen, dark algal, and light algal, were collected during the summer 2017, fall 2017, and spring 2018 seasons to discern differences between two vegetation states (grass and tarbush). A total of 51 biocrusts were collected from 3 tarbush sites and 3 grass sites. Phospholipid fatty acid analysis was used to characterize the microfloral community, while a modified extraction method was employed to observe direct counts of microfauna (multicellular microbes and protists). Soil chemical analysis was also used to obtain nutrient concentrations of each biocrust. Data include microfauna counts, microflora biomass, and soil nutrient composition. This study is complete.

opencc-zeroMay 2020View details →

Data from: Upper Toarcian (Lower Jurassic) marine gastropods from the Cleveland Basin, England: systematics, palaeobiogeography and contribution to biotic recovery from the early Toarcian extinction event

Here we describe a new late Toarcian (Lower Jurassic) marine gastropod fauna from rocks of the Cleveland Basin exposed on the North Yorkshire coast of England. The fossil assemblage comprises sixteen species, of which three are new: Katosira? bicarinata sp. nov., Turritelloidea stepheni sp. nov. and Striactaenonina elegans sp. nov. Four species are described in open nomenclature as Tricarilda? sp., Jurilda sp., Cylindrobullina sp. and Cossmannina sp. The other species have previously been described: Coelodiscus minutus (Schübler in Zieten), Procerithium quadrilineatum (Römer), Pseudokatosira undulata (Benz in von Zieten), Palaeorissoina aff. acuminata (Gründel, 1999b), Pietteia unicarinata (Hudleston), Globularia cf. canina (Hudleston), Striactaeonina cf. richterorum Schulbert & Nützel, Striactaenonina aff. tenuistriata (Hudleston) and Sulcoactaeon sedgvici (Phillips). Most of these species are the earliest records of their respective genera and show palaeobiogeographical connections with contemporary gastropod associations from other regions of Europe and South America. The taxonomic composition of the late Toarcian Cleveland Basin gastropod assemblage differs substantially from the faunas of the late Pliensbachian and early Toarcian Tenuicostatum Zone, showing the strong effect of the early Toarcian mass extinction event on the marine gastropod communities in the basin. Only a few gastropod species are shared between the late Toarcian faunas and the much more diverse Aalenian gastropod faunas in the Cleveland Basin, suggesting there was a facies control on gastropod occurrences at that time. This is also a potential explanation for the taxonomic differences between the late Toarcian gastropod faunas in the Cleveland Basin and those in France, and Northern and Southern Germany.

opencc-by-4.0Sep 2015View details →

Figure 2 in Biotic components of dung beetles (Insecta: Coleoptera: Scarabaeidae: Scarabaeinae) from Pantanal - Cerrado Border and its implications for Chaco regionalization

Figure 2. Continued.

opencc-by-4.0Sep 2015View details →

Figure 2 in Biotic components of dung beetles (Insecta: Coleoptera: Scarabaeidae: Scarabaeinae) from Pantanal - Cerrado Border and its implications for Chaco regionalization

Figure 2. Continued.

opencc-zeroAug 2020View details →

Demographic analysis of invasible habitat fraction identifies context-dependent roles of resource availability and biotic resistance in determining invasion success

Theories of plant invasions predict that plant communities should be more easily invaded when resources increase and/or competition decreases. We tested this with an experimentally introduced plant population by manipulating precipitation and resident community biomass. We used a spatially-explicit demographic approach to develop a new population-level metric of invasibility that quantifies the invasible habitat fraction (IHF) across the landscape. The existing community was essentially uninvasible (median IHF ≈ 0%), but experimental manipulations greatly increased the range of outcomes, with maximum observed IHF values over 50%. However, changes in invasibility were often context-dependent, resulting in some outcomes that aligned with existing theory, and others that were not readily predicted. Moreover, variation in invasibility was often driven by specific sets of invader demographic vital rates. Removing competitors revealed the capacity for strong biotic resistance, but this interacted with precipitation such that little biotic resistance was detected under drought conditions. Adding precipitation typically had little positive effect on invasibility, and moderate drought relief led to relatively high invasibility. However, the latter was driven to a large extent by interactions with mammal herbivory that otherwise inhibited invasion in one year. Synthesis. Our findings show that interactions between abiotic and biotic factors, as well as legacy effects, can strongly mediate invasibility. This study also highlights the importance of incorporating spatial heterogeneity into population-level assessments of invasion, as initial population declines do not necessarily indicate resistance to invasion.

opencc-zeroAug 2020View details →

Trade-offs between seed size and biotic interactions contribute to coexistence of co-occurring species that vary in fecundity

Despite theoretical advances, the ecological factors and functional traits that enable species varying in seed size and fecundity to coexist remain unclear. Given inherent fecundity advantages, why don't small-seeded species dominate communities? In perennial grasslands, we evaluated whether small-seeded species are less tolerant of competition from the community dominant bunchgrass than large-seeded species but also less vulnerable to seed predation by mice. We also explored whether trade-offs involving competitive tolerance include two other functional traits, height and leaf mass per area (LMA). We added seeds of 17 forb species to plots where bunchgrass competition and rodent seed predation were manipulated across sites varying in bunchgrass productivity and thus competitive intensity. Seeds were added at densities mimicking interspecific variation in fecundity among target species. Standardizing for differences in fecundity (i.e. seed input; which enabled us to evaluate inherent interspecific differences in susceptibility to biotic interactions), bunchgrass competition more greatly reduced recruitment and establishment of small vs. large-seeded species, whereas rodent seed predation more greatly reduced the recruitment of large- versus small-seeded species. Plant height and LMA were unrelated to the competition effect size. Small-seeded species abundance decreased across sites increasing in bunchgrass productivity, whereas this was not the case for large-seeded species. For adult plants but not seedlings, community weighted functional trait means (CWM) for seed size, height, and LMA increased in plots with versus without bunchgrass competition and the CWM for seed size and height also increased at sites with greater bunchgrass productivity (for adults only). In contrast, rodent seed predation had no significant effects on CWM seed size. At the end of the experiment, adult abundance positively correlated with plant fecundity in plots lacking bunchgrass, indicating the inherent advantages accrued to high fecundity small-seeded species. However, with bunchgrass competition, abundances were equalized across species due to reduced competitive tolerance of high fecundity small-seeded species. Synthesis: Our results suggest that coexistence among subordinate forb species varying in seed size and fecundity is in-part due to a trade-off involving competitive tolerance and fecundity, mediated by seed size and associated functional traits.

opencc-by-4.0Sep 2020View details →

Data from: Disproportionate extinction of South American mammals drove the asymmetry of the Great American Biotic Interchange

Annotated R codes and datasets used in: Carrillo et al. 2020. Disproportionate extinction of South American mammals drove the asymmetry of the Great American Biotic Interchange. Proc. Natl. Acad. Sci. U.S.A.

opencc-zeroSep 2021View details →

Climate change drives spatial mismatch and threatens the biotic interactions of the Brazil nut tree

Aim: Climate change and deforestation will redistribute the biodiversity in the next century. Species-specific differences in the response to such stressors will lead to distribution decoupling of interacting species, yet consequences for ecosystem services are poorly known. Here, we assess the potential effects of future niche mismatch on a key ecosystem service mediated by seed dispersal and pollination interactions in the Amazon: the sustainable exploitation of Brazil nuts. Location: The Amazon. Major taxa studied: Woody plant, medium-sized mammals, and insects. Time period: Present day, end of the 21st Century. Methods: Combining ecological niche models to simulations of tree cover loss and dispersal constraints, we compare the forecasted distribution of the plant to that of its interacting fauna of pollinators and seed dispersers. Results: Our projections indicate that climate change itself could have no or slightly negative effects on the distribution of the Brazil nut tree, expected to increase by 6% by year 2090. However, range contractions of nearly half of all the suitable climate for pollinators may lead up to 80% reduction on co-occurrence potential. In addition, local pollinator richness is expected to reduce by 20%, with likely consequences for pollination redundancy and resilience to subsequent environment changes. Although reductions on the suitable area of some seed dispersers were also forecasted in the future, potential co-occurrence with the plant and local species richness were mostly unabated in most of our projections. Main conclusion: The forecasted declines in pollinator diversity may hamper ecosystem function redundancy and threaten the long-term resilience of the services provided by Brazil nut trees. Such pervasive and indirect effects of climate change, often neglected and unaccounted for in most conservation assessments, may cascade into economies and human well-being worldwide.

opencc-zeroDec 2020View details →

The biotic interactions hypothesis partially explains bird species turnover along a lowland Neotropical precipitation gradient

Aim We evaluated the influence of climate in determining bird communities along precipitation gradients. We argue that mechanisms responsible for community turnover along precipitation gradients are similar to mechanisms operating along temperature and latitudinal gradients. We test the hypothesis that environmental conditions affect community composition in dry forests, whereas biotic interactions affect community composition in wet forests. Location Low-elevation forests along a precipitation gradient in Colombia where precipitation ranges from 700 – 4000 mm annually but neither temperature or elevation change. Time period Present day Major Taxa Studied Tropical Forest Birds. Methods We performed 291 bird counts in nine study areas across the ~3000 mm range of variation in precipitation. In each locality we obtained climatic characteristics, and a phylogenetic, morphological and physiological proxy data set to test predictions about the evolutionary relationships and distribution of traits in each community. Results Bird communities changed abruptly along the precipitation gradient and could be divided into dry and wet forest communities. Analyses of phylogenetic relationships, trait space, and observations at nests suggested that environmental filtering is more important in dry forest, especially for breeding. In contrast, we found little evidence that competition was more important in wet forest. Nest predation or competition for nest space, however, may be more critical in wetter forests. Conclusions The two distinct bird communities we documented suggest that lowland precipitation gradients, where temperature is constant can be as important as temperature gradients in generating high beta diversity. We conclude that the breeding process in bird communities might be crucial for determining community assembly along environmental gradients. Given that recent population declines in tropical birds have been attributed to changes in precipitation, by understanding the mechanisms underlying community assembly along precipitation gradients our study may improve our ability to understand those declines and predict the effects of climate change on neotropical avifauna.

opencc-by-4.0Dec 2020View details →

Global Climatic, Biotic, and Topographic Asymmetries

Calculated asymmetries in topography and environmental variables over the entire Earth, 0.25 dd spatial resolution. Associated with the paper: Smith, T., & Bookhagen, B. (2020). Climatic and biotic controls on topographic asymmetry at the global scale. Journal of Geophysical Research: Earth Surface, 126, e2020JF005692. https://doi.org/10.1029/2020JF005692 Individual file descriptions: 1. DrainageArea_Key -- Metadata for the files DrainageAsymmetries*.csv 2. DrainageAsymmetries_0.01_1_Hill.csv -- Drainage area statistics for only hillslopes (0.01 to 1 sq km drainage area threshold) 3. DrainageAsymmetries_0.1_100_Fluvial.csv -- Drainage area statistics for only fluvial network (0.1 to 100 sq km drainage area threshold) 4. Topography_Key.csv -- Metadata for the files TopoClimateAsymmetries.csv and Insolation_Asymmetries_1hr_pvlib.csv 5. TopoClimateAsymmetries.csv -- Environmental, Climatic, and Topographic variables calculated over the entire Earth 6. Insolation_Asymmetries_1hr_pvlib.csv - Results of a received insolation simulation using PVLIB (Holmgren et al., 2018) for inclined surfaces based on our average topography over the globe 7. Gridding_Command.txt -- A short Python script illustrating how to convert the CSV files into gridded TIF files for further visualization 8. TA/VCF _ NvS/EvW - North-south and east-west asymmetries in topographic asymmetry (TA) and vegetation cover (VCF), provided as TIF files for convenience

opencc-zeroOct 2019View details →

Environmental and biotic drivers of soil microbial β‐diversity across spatial and phylogenetic scales

Soil microbial communities play a key role in ecosystem functioning but still little is known about the processes that determine their turnover (β-diversity) along ecological gradients. Here, we characterize soil microbial β-diversity at two spatial scales and at multiple phylogenetic grains to ask how archaeal, bacterial and fungal communities are shaped by abiotic processes and biotic interactions with plants. We characterized microbial and plant communities using DNA metabarcoding of soil samples distributed across and within eighteen plots along an elevation gradient in the French Alps. The recovered taxa were placed onto phylogenies to estimate microbial and plant β-diversity at different phylogenetic grains (i.e. resolution). We then modeled microbial β-diversities with respect to plant β-diversities and environmental dissimilarities across plots (landscape scale) and with respect to plant β-diversities and spatial distances within plots (plot scale). At the landscape scale, fungal and archaeal β-diversities were mostly related to plant β-diversity, while bacterial β-diversities were mostly related to environmental dissimilarities. At the plot scale, we detected a modest covariation of bacterial and fungal β-diversities with plant β-diversity; as well as a distance–decay relationship that suggested the influence of ecological drift on microbial communities. In addition, the covariation between fungal and plant β-diversity at the plot scale was highest at fine or intermediate phylogenetic grains hinting that biotic interactions between those clades depends on early-evolved traits. Altogether, we show how multiple ecological processes determine soil microbial community assembly at different spatial scales and how the strength of these processes change among microbial clades. In addition, we emphasized the imprint of microbial and plant evolutionary history on today's microbial community structure.

opencc-zeroDec 2019View details →

Local adaptation to biotic interactions: a meta-analysis across latitudes

Adaptation to local conditions can increase species' geographic distributions and rates of diversification, but which components of the environment commonly drive local adaptation—particularly the importance of biotic interactions—is unclear. Biotic interactions should drive local adaptation when they impose consistent divergent selection; if this is common we expect transplant experiments to detect more frequent and stronger local adaptation when biotic interactions are left intact. We tested this hypothesis using a meta-analysis of transplant experiments from >125 studies (mostly on plants). Overall, local adaptation was common and biotic interactions affected fitness. Nevertheless, local adaptation was neither more common nor stronger when biotic interactions were left intact, either between experimental treatments within studies (control vs. biotic interactions experimentally manipulated) or between studies that used natural vs. biotically-altered transplant environments. However, the effect of ameliorating negative interactions varied with latitude, suggesting that interactions may promote local adaptation more often in tropical vs. temperate ecosystems, though few tropical studies were available to test this. Our results suggest that biotic interactions often fail to drive local adaptation even though they strongly affect fitness, perhaps because temperate biotic environments are unpredictable at the spatiotemporal scales required for local adaptation.