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opencc-zeroNov 2022View details →

Data from: Smoke-driven changes in photosynthetically active radiation during the U.S. agricultural growing season

Wildfire smoke is frequently present over the U.S. during the agricultural growing season and will likely increase with climate change. Studies of smoke impacts have largely focused on air quality and human health; however, understanding smoke's impact on photosynthetically active radiation (PAR) is essential for predicting how smoke affects plant growth. We compare surface shortwave irradiance and diffuse fraction (DF) on smoke-impacted and smoke-free days from 2006-2020 using data from multifilter rotating shadowband radiometers at ten U.S. Department of Agriculture (USDA) UV-B Monitoring and Research Program stations and smoke plume locations from operational satellite products. On average, 20% of growing season days are smoke-impacted, but smoke prevalence increases over time (r = 0.60, p < 0.05). Smoke presence peaks in the mid- to late growing season (i.e., July, August), particularly over the northern Rocky Mountains, Great Plains, and Midwest. We find an increase in the distribution of PAR DF on smoke-impacted days, with larger increases at lower cloud fractions. On clear-sky days, daily average PAR DF increases by 10 percentage points when smoke is present. Spectral analysis of clear-sky days shows smoke increases DF (average: +45%) and decreases total irradiance (average: -6%) across all six wavelengths measured from 368-870 nm. Optical depth measurements from ground and satellite observations both indicate that spectral DF increases and total spectral irradiance decreases with increasing smoke plume optical depth. Our analysis provides a foundation for understanding smoke's impact on PAR, which carries implications for agricultural crop productivity under a changing climate.

Army ant males lose seasonality at a site on the equator

Army ants are keystone predators in the tropics and subtropics. During reproduction, males fly between colonies to mate with unmated, wingless queens. The males of most species are attracted to lights, and thus their presence and the timing of reproduction can be monitored using light traps. Previous studies examined the seasonality of army ant male reproduction and its relationship to climate factors at individual sites, but less is known about variation among sites. We examined army ant male flight seasonality at three sites: (1) La Selva Biological Station in Costa Rica, a site with weak temperature seasonality and moderate rainfall and day length seasonality, (2) Yasuní National Park, Ecuador, a site with no temperature or day length seasonality and very weak rainfall seasonlity, and (3) the state of Paraná in southern Brazil, a site with very strong temperature, rainfall, and day length seasonality. Army ants showed strong seasonality at the La Selva and Paraná sites, and very weak to no seasonality at the Yasuní site. At La Selva and Paraná, flight times varied among species, but were very predictable from year to year, which suggests day length or temperature as predictable cues rather than rainfall. Lack of seasonal cues near the equator may be a challenge for army ant species that need to synchronize colony reproduction, and thus may have conservation implications for minimum population sizes needed to ensure stable populations.

Data from: Season and herbivore defence trait mediate tri-trophic interactions in tropical rainforest

Bottom-up effects from host plants and top-down effects from predators on herbivore abundance and distribution vary with physical environment, plant chemistry, predator and herbivore trait and diversity. Tri-trophic interactions in tropical ecosystems may follow different patterns from temperate ecosystems due to differences in above abiotic and biotic conditions. We sampled leaf-chewing larvae of Lepidoptera (caterpillars) from a dominant host tree species in a seasonal rainforest in Southwest China. We reared out parasitoids and grouped herbivores based on their diet preferences, feeding habits, and defence mechanisms. We compared caterpillar abundance with leaf numbers ('bottom-up' effects) and parasitoid abundance ('top-down' effects) between different seasons and herbivore traits. We found bottom-up effects were stronger than top-down effects. Both bottom-up and top-down effects were stronger in the dry season than in the wet season, which were driven by polyphagous rare species and host plant phenology. Contrary to our predictions, herbivore traits did not influence differences in the bottom-up or top-down effects except for stronger top-down effects for shelter-builders. Our study shows season is the main predictor of the bottom-up and top-down effects in the tropics and highlights the complexity of these interactions.

opencc-by-4.0Dec 2022View details →

Earlier onset and shortened Meiyu season during the Last Interglacial based on dynamical downscaling simulations

This dataset includes the model outputs that could be used to reproduce the figures in our paper. A detailed description of the dataset is given in the word file.

Seasonal surface reflectance mosaics of Blackhawk Island, Wisconsin May-October 2018

This dataset contains high-resolution hyperspectral surface reflectance mosaics collected over Blackhawk Island, Wisconsin, USA. Images were collected at eight dates during the 2018 growing season (May – October) using a VNIR-SWIR (400–2400nm) HySpex airborne imaging system at 1m spatial resolution.

opencc-by-4.0Dec 2022View details →

Effects of the environmental conditions and seasonality on a population survey of the Andean Condor Vultur gryphus in the tropical Andes

Script, datasets, and other supplementary material in Márquez-Alvis et al. 2023 PeerJ. Background: Among the New World vultures, the Andean Condor is considered one of the most culturally and ecologically important species. However, their populations are declining over their entire distributional range. In response, conservation strategies have been implemented in many countries to reverse the increasing extinction risk of this species. The initiatives rely on extensive population surveys to gather basic information necessary to implement policies and to intervene efficiently. Still, there is a need to standardize the surveys based on seasonality and suitable environmental conditions throughout the species distribution.  Here, we provide the first assessment of how daily temperature, rainfall, and seasonality influence surveys of Andean Condors on a communal roost in the central Peruvian Andes. Methods: Using an autoregressive generalized linear model, we associated environmental variables with visual surveys of adult and young condors at three different times of the day and three times a week between June 2014 and March 2015. Results: We found that both adults and young Andean Condors showed a threefold reduction in the use of the communal roost after the beginning of the rainy season. Colder and drier days (dry season) are preferable for surveying, as we expect the total number of condors using communal roosts to reduce under rainy (rainfall = -0.53 ± 0.16) and warmer days (temperature= - 0.04 ± 0.02) days. Therefore, the significant variation in the use of roosts across seasons and hours should be carefully accounted for in national surveys, at the risk of undermining the full potential of the communal roost surveys. Moreover, we also found a strong bias towards immatures (about 76%) in the adult:immature ratio and a remarkable absence of Andean Condors during the wet season. These results suggest that the species might be using other unknown communal roosts hierarchically. Such results provide key information for selecting priority areas for conservation and selecting the best time to survey this species in the tropical Andes. Finally, it may open a fruitful avenue for further research on the protection of the Andean Condor.

Data for: Sex-based divergence in tidal, lunar and seasonal cycles of activity in the olive sea snake, Aipysurus laevis (Elapidae, Hydrophiinae)

Marine environments show strong cycles at daily (tidal), monthly (lunar) and seasonal timeframes, and the behavioural responses of marine organisms to such cycles may depend upon ecological and behavioural traits that differ between the sexes. Underwater observations of free-ranging olive sea snakes (Aipysurus laevis, Hydrophiinae, Elapidae) at a site on the southern Great Barrier Reef revealed sex-based divergences in the effects of abiotic cycles on snake activity. Female snakes were active primarily on high and rising tides that allowed access to shallow-water sites for foraging. In contrast, male snakes were active primarily on low and falling tides, especially near the time of the full moon (when tidal range is highest), conditions that may restrict a female snake's ability to evade a courting male. Males were common on the coral-reef site during winter (the mating season), but were rarely seen during summer, whereas females remained on the reef year-round. This highly sexually dimorphic species shows strong temporal separations between the sexes in patterns of activity.

Data from: Genomic loci involved in sensing environmental cues and metabolism affect seasonal coat shedding in Bos taurus and Bos indicus cattle

Seasonal shedding of winter hair at the start of summer is well-studied in wild and domesticated populations. However, the genetic influences on this trait and their interactions are poorly understood. We use data from 13,364 cattle with 36,899 repeated phenotypes to investigate the relationship between hair shedding and environmental variables, single nucleotide polymorphisms, and their interactions to understand quantitative differences in seasonal shedding. Using de-regressed estimated breeding values from a repeated records model in a genome-wide association analysis (GWAA) and meta-analysis of year-specific GWAA gave remarkably similar results. These GWAA identified hundreds of variants associated with seasonal hair shedding. There were especially strong associations on chromosomes 5 and 23. Genotype-by-environment interaction GWAA identified 1,040 day-length-by-genotype interaction associations and 17 apparent temperature-by-genotype interaction associations with hair shedding, highlighting the importance of day length on hair shedding. Accurate genomic predictions of hair shedding were created for the entire dataset, Angus, Hereford, Brangus, and multi-breed datasets. Loci related to metabolism and light-sensing have a large influence on seasonal hair shedding. This is one of the largest genetic analyses of a phenological trait and provides insight for both agriculture production and basic science.

Datasets for: Colony-nesting gulls restrict activity levels of native top carnivore during the breeding season

Although nesting in colonies can offer substantial reproductive benefits for many seabird species, increased visibility to predators remains a significant disadvantage for most colony-breeders. To counteract this, some seabird species have evolved aggressive nest defense strategies to protect vulnerable eggs and chicks. Here we used an experimental approach to test whether colony inhabitance by breeding gulls (Larus spp.) in western Norway impacts visitation rates of a native, mammalian predator, the Eurasian otter (Lutra lutra) during the breeding season. Camera traps were placed inside of and on the periphery of seabird colonies prior to the breeding season and left to run for one continuous year. Sighting frequency of otters on these cameras was compared to a control region free of gull nesting. We found that otter activity was significantly reduced on the colonies when gulls were incubating and rearing chicks, compared to time periods when gulls were building nests and absent from the colonies. Rhythmic activity patterns did not seem to be significantly impacted by the presence of gulls. This study provides clear evidence that certain colony-nesting species can have a direct, negative impact on visitation rates of a native carnivore. Seasonal carnivore activity patterns are likely to be highly dependent on differing nesting strategies and level of nest defense by seabirds.

opencc-by-4.0Jan 2023View details →

Pathways of methane removal in the sediment and water column of a seasonally anoxic eutrophic marine basin - dataset

Dataset used in the article: "Pathways of methane removal in the sediment and water column of a seasonally anoxic eutrophic marine basin", Zygadlowska et al., 2023.

A new, disjunct species of Bahiana (Euphorbiaceae-Acalyphoideae): Phytogeographic connections between the seasonally dry tropical forests of Peru and Brazil, and a review of spinescence in the family

Bahiana is expanded from 1 to 2 species with the description of B. occidentalis K. Wurdack, sp. nov. as a new endemic of the seasonally dry tropical forests (SDTFs) of Peru. The disjunct distribution of Bahiana with populations of B. occidentalis on opposite sides of the Andes in northwestern Peru (Tumbes, San Martín) and B. pyriformis in eastern Brazil (Bahia) adds to the phytogeographic links among the widely scattered New World SDTFs. Although B. occidentalis remains imperfectly known due to lack of flowering collections, molecular phylogenetic results from four loci (plastid matK, rbcL, and trnL-F; and nuclear ITS) unite the two species as does gross vegetative morphology, notably their spinose stipules, and androecial structure. Spinescence in Euphorbiaceae was surveyed and found on vegetative organs in 25 genera, which mostly have modified sharp branch tips. Among New World taxa, spines that originate from stipule modifications only occur in Bahiana and Acidocroton, while the intrastipular spines of Philyra are of uncertain homologies.

opencc-by-4.0Jan 2023View details →

Data for Intra-seasonal variability in sediment provenance and transport processes in the Brahmaputra basin

No description provided.

opencc-by-4.0Jan 2023View details →

WRF-Noah/Alpine3D simulations for 2018-2021 snow seasons in Italian Central Apennines

This dataset contains the results of two numerical simulations over Italian Central Apennines at 3 km resolution for the three snow seasons 2018/19, 2019/20 and 2020/21. The file wrf-noah_2018-2021.nc contains the WRF-Noah model output, while the file wrf-alpine3d_2018-2021.nc contains the WRF-Alpine3D model output.

Seasonal variation of behavior and brain size in a freshwater fish

Teleost fishes occupy a range of ecosystem and habitat types subject to large seasonal fluctuations. Temperate fishes in particular, survive large seasonal shifts in temperature, light availability, and access to certain habitats. Mobile species like lake trout (Salvelinus namaycush) can behaviorally respond to seasonal variation by shifting their habitat deeper and further offshore in response to warmer surface water temperatures during the summer. During cooler seasons, use of more structurally complex nearshore zones by lake trout could increase cognitive demands and potentially result in a larger relative brain size during those periods. Yet, there is limited understanding of how such behavioral responses to a seasonally shifting environment might shape, or be shaped by, the nervous system. Here we quantified variation in relative brain size and the size of five externally visible brain regions in lake trout, across six consecutive seasons in two different lakes. Acoustic telemetry data from one of our study lakes was collected during the study period from a different subset of individuals and used to infer relationships between brain size and seasonal behaviors (habitat use and movement rate). Our results indicated that lake trout relative brain size was larger in the fall and winter compared to the spring and summer in both lakes. Larger brains coincided with increased use of nearshore habitats and increased horizontal movement rates in the fall and winter based on acoustic telemetry. The telencephalon followed the same pattern as whole brain size, while the other brain regions (cerebellum, optic tectum, olfactory bulbs, hypothalamus) were only smaller in the spring. These findings provide evidence that flexibility in brain size could underpin shifts in behavior, which could potentially subserve functions associated with differential habitat use during cold and warm seasons and allow fish to succeed in seasonally variable environments.

Soil microbial relative resource limitation exhibited contrasting seasonal patterns along an elevational gradient in Yulong snow mountain

1. Microbial relative resource limitations represented by enzyme stoichiometry reflect the relationship between microbial nutrient requirements and nutrient status in soil, but the issue on whether alterations in environments along elevational gradients affect the magnitude of microbial relative resource limitations remains unresolved. 2. Here, we examined seasonal patterns in microbial relative carbon (C) and phosphorus (P) limitations indicated by vector lengths and angles using relative proportional enzymatic activities and key controlling factors along an elevational gradient in the Yulong Snow Mountain. We also analyzed the relationships between microbial metabolic processes and microclimates (i.e., soil moisture and temperature), soil properties (i.e., pH and soil texture), and microbial attributes (i.e., microbial biomass and fungal: bacterial ratio). 3. We found that soil microbial relative C limitation decreased with increasing elevations, with lower levels observed in the dry season than in the wet season. In contrast, soil microbial relative P limitation varied significantly with elevations, with linearly increasing trends in wet seasons but unimodal trends in dry seasons. Meanwhile, we found higher relative C limitation in the coniferous forest but higher relative P limitation in the broad-leaved forest. Notably, soil microbial relative C limitation was primarily affected by the soil microenvironment (i.e., soil temperature) and substrate quantity (i.e., the ratio of soil dissolved organic C to available P), whereas soil microbial relative P limitation could be alleviated by increasing microbial relative C limitation combined with increasing soil pH. Additionally, the significant linear pattern of the C use efficacy with elevations was only observed in the wet seasons, which was directly influenced by soil microclimates and microbial relative C limitation. 4. Overall, our results provided important information for better understanding the essential role of microbial processes in the regulation of C and P cycling in vulnerable subtropical mountain ecosystems.

Data for: Seasonal variability in resilience of a coral reef fish to marine heatwaves and hypoxia

Climate change projections indicate more frequent and severe tropical marine heatwaves (MHWs) and accompanying hypoxia year-round. However, most studies have focused on peak summer peak conditions under the assumption that annual maximum temperatures will induce the greatest physiological consequences. This study challenges this idea by characterizing seasonal MHWs (i.e., mean, maximum, and cumulative intensities, durations, heating rates, and mean annual occurrence) and comparing metabolic traits (i.e., standard metabolic rate (SMR), Q10 of SMR, maximum metabolic rate (MMR), aerobic scope, and critical oxygen tension (Pcrit)) of winter- and summer-acclimatized convict tang (Acanthurus triostegus) to the combined effects of MHWs and hypoxia. Fish were exposed to one of six MHW treatments with seasonally varying maximum intensities (winter: 24.5, 26.5, 28.5°C; summer: 28.5, 30.5, 32.5°C), representing past and future MHWs under IPCC projections (i.e., +0, +2, +4°C). Surprisingly, MHW characteristics did not significantly differ between seasons, yet SMR was more sensitive to winter MHWs (mean Q10 = 2.92) than summer MHWs (mean Q10 = 1.81), despite higher absolute summer temperatures. Concurrently, MMR increased similarly among winter +2°C and +4°C treatments (i.e., 26.5, 28.5°C) and all summer MHW treatments, suggesting a ceiling for maximal MMR increase. Aerobic scope did not significantly differ between seasons nor among MHW treatments. While mean Pcrit did not significantly vary between seasons, warming of +4°C during winter (i.e., 28.5°C) significantly increased Pcrit relative to the winter control group. Contrary to the idea of increased sensitivity to MHWs during the warmest time of year, our results reveal heightened sensitivity to the deleterious effects of winter MHWs, and that seasonal acclimatization to warmer summer conditions may bolster metabolic resilience to warming and hypoxia. Consequently, physiological sensitivity to MHWs and hypoxia may extend across larger parts of the year than previously expected, emphasizing the importance of evaluating climate change impacts during cooler seasons when essential fitness-related traits such as reproduction occur in many species.

opencc-by-4.0Feb 2023View details →

Thermoregulatory behavior varies with altitude and season in the sceloporine Mesquite lizard.

In ectothermic vertebrates, body temperature is the factor that most affects physiology and behavior. Most ectotherms show limited physiological control of body temperature, so they use behavioral strategies to regulate and maintain a constant temperature within a range. The variation of environmental temperature due to altitude and seasonality could have a great impact on the regulation of body temperature in lizards, even more so in elevation gradients, in which environmental temperature decreases with elevation. We chose three populations of the lizard Sceloporus grammicus that inhabit along an altitudinal gradient at 2500, 3400, and 4100 m and compared some seasonal (spring, summer, and autumn) thermal traits: 1. Body temperature in the field when the lizards were active 2. The relationship between body, air, and substrate temperatures where they were first observed 3. The temperature that they selected in a thermal gradient in laboratory conditions 4. The precision of thermoregulation, the thermal quality of the environment, the effectiveness of thermoregulation, and the Blouin-Demers index 5. The ambient temperatures available during the period of activity (Operative temperature) Thus, our data suggest that the thermal quality of the environment is low at higher altitudes and in summer, while lizards are capable of modifying their body temperature when they are active in the field and the temperature they select in the laboratory due to the effect of altitude and of the season, according to the requirements they have in each part of the year.

Evaluating niche changes during invasion with seasonal models in Capsella bursa‐pastoris

Premise Researchers often use ecological niche models to predict where species might establish and persist under future or novel climate conditions. However, these predictive methods assume species have stable niches across time and space. Furthermore, ignoring the time of occurrence data can obscure important information about species reproduction and ultimately fitness. Here, we assess and compare ecological niche models generated from full-year averages to seasonal models Methods In this study, we generate full-year and monthly ecological niche models for Capsella bursa-pastoris in Europe and North America to see if we can detect changes in the seasonal niche of the species after long-distance dispersal. Key Results We find full-year ecological niche models have low transferability across continents and there are continental differences in the climate conditions that influence the distribution of C. bursa-pastoris. Monthly models have greater predictive accuracy than full-year models in cooler seasons but no monthly models are able to predict North American summer occurrences very well. Conclusions The relative predictive ability of European monthly models compared to North American monthly models suggests a change in the seasonal timing between the native range to the non-native range. These results highlight the utility of ecological niche models at finer temporal scales in predicting species distributions and unmasking subtle patterns of evolution.

Data from: Acoustic indices estimate breeding bird species richness with daily and seasonally variable effectiveness in lowland temperate Białowieża forest

Biodiversity monitoring is important to follow temporal changes of the environment. We examined whether acoustic indices can be used as a rapid and easy-to-apply tool for bird biodiversity estimation in one of the least changed European lowland forests – the Białowieża Forest. We collected soundscape recordings in early and late spring at 84 randomly chosen recording points. At each recording point, we analysed 72 1-min sound samples to evaluate how well acoustic indices predict bird species richness from the perspective of a single sound sample, single survey, and recording point, and how they follow the daily pattern of singing activity. For each 1-min sound sample, we prepared a list of vocalizing bird species and calculated three acoustic indices: Bioacoustic Index (BI), Acoustic Complexity Index (ACI), and Acoustic Diversity Index (ADI). We found that from the perspective of a single 1-min sound sample, BI best predicts the bird species richness, independently of time in the season but variably across the day, while ACI and ADI showed weaker and seasonally and daily variable dependency. The correlation between each index and the number of bird species was stronger in the early survey than in the late survey. All acoustic indices followed daily bird activity patterns, yet they provided greater values before the peak of the species richness estimated by manual spectrogram scanning and listening to recordings. We showed that acoustic indices correlate moderately to strongly with the bird species richness obtained by manual spectrogram scanning and listening to recordings by humans. Therefore, acoustic indices can be used as a tool for rapid estimation of bird biodiversity in temperate forests. However, daily and seasonal variation in effectiveness of acoustic indices should be taken into account in the analysis.