bluuebunny/crossref_metadata_2025_split huggingface dataset:
Habitat characteristics or protected area size: What is more important for the composition and diversity of mammals in nonprotected areas?
Authors: Li Wenbo , Yang Peipei , Li Bowen , Liu Chao , Sun Lixing , Li Jinhua 
Published: May 2021

AbstractThe margins of protected areas are usually considered to have greater forest degradation, and given that most mammals live outside protected areas, researchers and conservation practitioners are increasingly recognizing that nonprotected areas must be incorporated into conservation strategy. However, the strategy used to manage these areas still involves increasing the size of protected areas, while not considering the habitat characteristics and requirements of the species. In this study, during a 3‐year period, camera trap and habitat characteristic surveys were used to estimate composition, diversity, and habitat characteristics of mammals to determine habitat characteristics or increase the size of protected areas what should be considered first for mammals’ conservation in a nonprotected area near the Huangshan Mountains in Anhui Province, China. From June 2017 to October 2019, 18 species of mammals were recorded, more than in any other protected area nearby. The linear model analysis results showed that habitat characteristics of mammals were different and showed a significant correlation with their relative abundance. Most species were related to vegetation characteristics, except primates (Macaca thibetana), and rodents (Leopoldamys edwardsi). Therefore, to establish conservation policies for nonprotected areas, habitat characteristics should be of prime concern, followed by increasing the size of protected areas to provide effective refuge areas for species conservation.
Diel patterns of predation and fledging at nests of four species of grassland songbirds
Authors: Ribic Christine A. , Rugg David J. , Ellison Kevin , Koper Nicola , Pietz Pamela J. 
Published: May 2021

AbstractAlthough it is common for nestlings to exhibit a strong bias for fledging in the morning, the mechanisms underlying this behavior are not well understood. Avoiding predation risk has been proposed as a likely mechanism by a number of researchers. We used video surveillance records from studies of grassland birds nesting in North Dakota, Minnesota, and Wisconsin to determine the diel pattern of nest predation and fledging patterns of four ground‐nesting obligate grassland passerines (Grasshopper Sparrow (Ammodramus savannarum), Savannah Sparrow (Passerculus sandwichensis), Bobolink (Dolichonyx oryzivorus), and Eastern Meadowlark (Sturnella magna)). We used the nest predation pattern as a surrogate for predation activity to test whether nestlings minimized predation risk by avoiding fledging when predation activity was high and preferentially fledging when predation risk was low. Predation activity was significantly lower starting 3 hr before sunrise and ending 3 hr after sunrise, followed by a transition to a period of significantly higher activity lasting for 4 hr, before declining to an average activity level for the rest of the diel period. There was little evidence that the four grassland bird species avoided fledging during the high‐risk period and Savannah Sparrow fledged at higher rates during that period. All four species had hours during the low‐risk period where they fledged at higher rates, but only Grasshopper Sparrow fledged preferentially during that period. Bobolink and Eastern Meadowlark had multiple hours with high fledging rates throughout the daytime period, resulting in no relationship between probability of fledging and predation risk. Given the species variability in fledging pattern seen in our study, it is unlikely that there is a universal response to any driver that affects time of fledging. Further study is needed to understand the complex interplay between species ecology and drivers such as physiology, energetics, and predation in affecting grassland bird fledging behavior.
Monitoring the dead as an ecosystem indicator
Authors: Newsome Thomas M. , Barton Brandon , Buck Julia C. , DeBruyn Jennifer , Spencer Emma , Ripple William J. , Barton Philip S. 
Published: May 2021

AbstractDead animal biomass (carrion) is present in all terrestrial ecosystems, and its consumption, decomposition, and dispersal can have measurable effects on vertebrates, invertebrates, microbes, parasites, plants, and soil. But despite the number of studies examining the influence of carrion on food webs, there has been no attempt to identify how general ecological processes around carrion might be used as an ecosystem indicator. We suggest that knowledge of scavenging and decomposition rates, scavenger diversity, abundance, and behavior around carrion, along with assessments of vegetation, soil, microbe, and parasite presence, can be used individually or in combination to understand food web dynamics. Monitoring carrion could also assist comparisons of ecosystem processes among terrestrial landscapes and biomes. Although there is outstanding research needed to fully integrate carrion ecology and monitoring into ecosystem management, we see great potential in using carrion as an ecosystem indicator of an intact and functional food web.
Calcicole–calcifuge plant strategies limit restoration potential in a regional semi‐arid flora
Authors: Cross Adam T. , Lambers Hans 
Published: May 2021

AbstractAimTo examine calcicole and calcifuge plant strategies, as well as nutrient‐acquisition strategies, as drivers of the distribution of species in response to edaphic factors, and the degree to which these strategies may act as filters to species establishment in ecological restoration on heavily altered or reconstructed substrates.LocationAn 82,000‐ha area within a major mining province in the Mid‐West region of Western Australia, harboring vegetation communities ranging from species‐poor halophytic scrub on saline flats to dense biodiverse shrubland on the skeletal soils of ancient Banded Ironstone Formations (BIF).MethodsUnivariate and multivariate analyses were employed to examine how variation in soil chemistry and landscape position (undulating plains, slopes, and BIF crests and ridges) influenced patterns of floristic diversity, calcifuge plant strategies, and nutrient‐acquisition strategies in 538 plant species from 830 relevés.ResultsLandscape position was the strongest driver of species richness and vegetation functional composition. Soils became increasingly acidic and P‐impoverished along an increasing elevational gradient. Vegetation from different landscape positions was not compositionally dissimilar, but vegetation of BIF crests and ridges was up to twice as biodiverse as vegetation from adjacent lower‐relief areas and harbored higher proportions of calcifuge species and species with mycorrhizal associations.Main conclusionsTopographic and edaphic complexity of BIF landforms in an otherwise relatively homogenous landscape has likely facilitated species accumulation over long time periods. They represent musea of regional floristic biodiversity, excluding only species that cannot establish or are inferior competitors in heavily weathered, acidic, skeletal, and nutrient‐impoverished soils. Plant strategies likely represent a major filter in establishing biodiverse, representative vegetation on postmining landforms in geologically ancient regions.
Speciation along a latitudinal gradient: The origin of the Neotropical cycad sister pair Dioon sonorense–D. vovidesii (Zamiaceae)
Authors: Gutiérrez‐Ortega José Said , Molina‐Freaner Francisco , Martínez José F. , Pérez‐Farrera Miguel Angel , Vovides Andrew P. , Hernández‐López Antonio , Tezuka Ayumi , Nagano Atsushi J. , Watano Yasuyuki , Takahashi Yuma , Murakami Masashi , Kajita Tadashi 
Published: May 2021

AbstractLatitude is correlated with environmental components that determine the distribution of biodiversity. In combination with geographic factors, latitude‐associated environmental variables are expected to influence speciation, but empirical evidence on how those factors interplay is scarce. We evaluated the genetic and environmental variation among populations in the pair of sister species Dioon sonorense–D. vovidesii, two cycads distributed along a latitudinal environmental gradient in northwestern Mexico, to reveal their demographic histories and the environmental factors involved in their divergence. Using genome‐wide loci data, we determined the species delimitation, estimated the gene flow, and compared multiple demographic scenarios of divergence. Also, we estimated the variation of climatic variables among populations and used ecological niche models to test niche overlap between species. The effect of geographic and environmental variables on the genetic variation among populations was evaluated using linear models. Our results suggest the existence of a widespread ancestral population that split into the two species ~829 ky ago. The geographic delimitation along the environmental gradient occurs in the absence of major geographic barriers, near the 28th parallel north, where a zonation of environmental seasonality exists. The northern species, D. vovidesii, occurs in more seasonal environments but retains the same niche of the southern species, D. sonorense. The genetic variation throughout populations cannot be solely explained by stochastic processes; the latitudinal‐associated seasonality has been an additive factor that strengthened the species divergence. This study represents an example of how speciation can be achieved by the effect of the latitude‐associated factors on the genetic divergence among populations.
Engaging students through online video homework assignments: A case study in a large‐enrollment ecology and evolution course
Authors: Gerhart Laci M. , Anderton Brittany N. 
Published: May 2021

AbstractOnline educational videos have the potential to enhance undergraduate biology learning, for example by showcasing contemporary scientific research and providing content coverage. Here, we describe the integration of nine videos into a large‐enrollment (n = 356) introductory evolution and ecology course via weekly homework assignments. We predicted that videos that feature research stories from contemporary scientists could reinforce topics introduced in lecture and provide students with novel insights into the nature of scientific research. Using qualitative analysis of open‐ended written feedback from the students on each video assigned throughout the term (n = 133–229 responses per video) and on end‐of‐quarter evaluations (n = 243), we identified common categories of student perspectives. All videos received more positive than negative comments and all videos received comments indicating that students found them intellectually and emotionally stimulating, accessible, and relevant to course content. Additionally, all videos also received comments indicating some students found them intellectually unstimulating, though these comments were generally far less numerous than positive comments. Students responded positively to videos that incorporated at least one of the following: documentary‐style filming, very clear links to course content (especially hands‐on activities completed by the students), relevance to recent world events, clarity on difficult topics, and/or charismatic narrators or species. We discuss opportunities and challenges for the use of online educational videos in teaching ecology and evolution, and we provide guidelines instructors can use to integrate them into their courses.
Physiological basis of interactive responses to temperature and salinity in coastal marine invertebrate: Implications for responses to warming
Authors: Torres Gabriela , Charmantier Guy , Wilcockson David , Harzsch Steffen , Giménez Luis 
Published: May 2021

AbstractDeveloping physiological mechanistic models to predict species’ responses to climate‐driven environmental variables remains a key endeavor in ecology. Such approaches are challenging, because they require linking physiological processes with fitness and contraction or expansion in species’ distributions. We explore those links for coastal marine species, occurring in regions of freshwater influence (ROFIs) and exposed to changes in temperature and salinity. First, we evaluated the effect of temperature on hemolymph osmolality and on the expression of genes relevant for osmoregulation in larvae of the shore crab Carcinus maenas. We then discuss and develop a hypothetical model linking osmoregulation, fitness, and species expansion/contraction toward or away from ROFIs. In C. maenas, high temperature led to a threefold increase in the capacity to osmoregulate in the first and last larval stages (i.e., those more likely to experience low salinities). This result matched the known pattern of survival for larval stages where the negative effect of low salinity on survival is mitigated at high temperatures (abbreviated as TMLS). Because gene expression levels did not change at low salinity nor at high temperatures, we hypothesize that the increase in osmoregulatory capacity (OC) at high temperature should involve post‐translational processes. Further analysis of data suggested that TMLS occurs in C. maenas larvae due to the combination of increased osmoregulation (a physiological mechanism) and a reduced developmental period (a phenological mechanisms) when exposed to high temperatures. Based on information from the literature, we propose a model for C. maenas and other coastal species showing the contribution of osmoregulation and phenological mechanisms toward changes in range distribution under coastal warming. In species where the OC increases with temperature (e.g., C. maenas larvae), osmoregulation should contribute toward expansion if temperature increases; by contrast in those species where osmoregulation is weaker at high temperature, the contribution should be toward range contraction.
Linking alternative reproductive tactics and habitat selection in Northern chamois
Authors: Corlatti Luca , Cotza Antonella , Nelli Luca 
Published: May 2021

AbstractIn polygynous ungulates, males may achieve fertilization through the use of alternative reproductive tactics (ARTs), discrete phenotypic variations evolved to maximize fitness. ARTs are often associated with different male spatial strategies during the rut, from territoriality to female‐following. Although variation in space use patterns of rutting male ungulates is known to be largely affected by the spatial distribution of females, information on the year‐round habitat selection of alternative reproductive types is scant. Here, we investigate the seasonal variation in habitat choice of a large mammal with ARTs (territoriality and nonterritoriality), the Northern chamois Rupicapra rupicapra. Global Positioning System (GPS) data on 28 adult males were collected between February 2010 and December 2013 in the Gran Paradiso National Park (Italy) and used to fit resource selection functions to explore the ART‐specific use of key topographic features, such as elevation, aspect, and slope, and vegetation phenology expressed as NDVI values. Territorial and nonterritorial chamois profoundly differed in their habitat selection not only during the rutting season. Compared to nonterritorial males, territorial males used lower elevations in summer and autumn, preferred southern slopes in spring and summer, and used steeper areas in summer but not in winter. We found no difference in seasonal selection of NDVI values between males adopting ARTs. Our results suggest that territorial males tend to occupy warmer, lower‐food‐quality habitats in late spring and summer, whereas nonterritorial males are free to follow and exploit vegetation phenology and more favorable temperatures. Different patterns of habitat selection may reflect different trade‐offs between the optimization of energy balances throughout the year and the increase of mating opportunities during the rut in males adopting alternative reproductive tactics.
Why do Argos satellite tags stop relaying data?
Authors: Hays Graeme C. , Laloë Jacques‐Olivier , Rattray Alex , Esteban Nicole 
Published: May 2021

Abstract

Satellite tracking of animals is very widespread across a range of marine, freshwater, and terrestrial taxa. Despite the high cost of tags and the advantages of long deployments, the reasons why tracking data from tags stop being received are rarely considered, but possibilities include shedding of the tag, damage to the tag (e.g., the aerial), biofouling, battery exhaustion, or animal mortality.

We show how information relayed via satellite tags can be used to assess why tracking data stop being received. As a case study to illustrate general approaches that are broadly applicable across taxa, we examined data from Fastloc‐GPS Argos tags deployed between 2012 and 2019 on 78 sea turtles of two species, the green turtle (Chelonia mydas) and the hawksbill turtle (Eretmochelys imbricata).

Tags transmitted for a mean of 267 days (SD = 113 days, range: 26–687 days, median = 251 days). In 68 of 78 (87%) cases, battery failure was implicated as the reason why tracking data stopped being received. Some biofouling of the saltwater switches, which synchronize transmissions with surfacing, was evident in a few tags but never appeared to be the reason that data reception ceased.

Objectively assessing why tags fail will direct improvements to tag design, setup, and deployment regardless of the study taxa. Assessing why satellite tags stop transmitting will also inform on the fate of tagged animals, for example, whether they are alive or dead at the end of the study, which may allow improved estimates of survival rates.
Nocturnal incubation recess and flushing behavior by duck hens
Authors: Croston Rebecca , Peterson Sarah H. , Hartman C. Alex , Herzog Mark P. , Feldheim Cliff L. , Casazza Michael L. , Ackerman Joshua T. 
Published: May 2021

AbstractIncubating birds must balance the needs of their developing embryos with their own physiological needs, and many birds accomplish this by taking periodic breaks from incubation. Mallard (Anas platyrhynchos) and gadwall (Mareca strepera) hens typically take incubation recesses in the early morning and late afternoon, but recesses can also take place at night. We examined nocturnal incubation recess behavior for mallard and gadwall hens nesting in Suisun Marsh, California, USA, using iButton temperature dataloggers and continuous video monitoring at nests. Fourteen percent of all detected incubation recesses (N = 13,708) were nocturnal and took place on 20% of nest‐days (N = 8,668). Video monitoring showed that hens covered their eggs with down feathers when they initiated a nocturnal recess themselves as they would a diurnal recess, but they left the eggs uncovered in 94% of the nocturnal recesses in which predators appeared at nests. Thus, determining whether or not eggs were left uncovered during a recess can provide strong indication whether the recess was initiated by the hen (eggs covered) or a predator (eggs uncovered). Because nest temperature decreased more rapidly when eggs were left uncovered versus covered, we were able to characterize eggs during nocturnal incubation recesses as covered or uncovered using nest temperature data. Overall, we predicted that 75% of nocturnal recesses were hen‐initiated recesses (eggs covered) whereas 25% of nocturnal recesses were predator‐initiated recesses (eggs uncovered). Of the predator‐initiated nocturnal recesses, 56% were accompanied by evidence of depredation at the nest during the subsequent nest monitoring visit. Hen‐initiated nocturnal recesses began later in the night (closer to morning) and were shorter than predator‐initiated nocturnal recesses. Our results indicate that nocturnal incubation recesses occur regularly (14% of all recesses) and, similar to diurnal recesses, most nocturnal recesses (75%) are initiated by the hen rather than an approaching predator.
The effect of nest temperature on growth and survival in juvenile Great TitsParus major
Authors: Corregidor‐Castro Alejandro , Jones Owen R. 
Published: May 2021

AbstractFor birds, maintaining an optimal nest temperature is critical for early‐life growth and development. Temperatures deviating from this optimum can affect nestling growth and fledging success with potential consequences on survival and lifetime reproductive success. It is therefore particularly important to understand these effects in relation to projected temperature changes associated with climate change.Targets set by the 2015 Paris Agreement aim to limit temperature increases to 2°C, and, with this in mind, we carried out an experiment in 2017 and 2018 where we applied a treatment that increased Great TitParusmajornest temperature by approximately this magnitude (achieving an increase of 1.6°C, relative to the control) during the period from hatching to fledging to estimate how small temperature differences might affect nestling body size and weight at fledging and fledging success.We recorded hatching and fledging success and measured skeletal size (tarsus length) and body mass at days 5, 7, 10, and 15 posthatch in nestlings from two groups of nest boxes: control and heated (+1.6°C).Our results show that nestlings in heated nest boxes were 1.6% smaller in skeletal size at fledging than those in the cooler control nests, indicating lower growth rates in heated boxes, and that their weight was, in addition, 3.3% lower.These results suggest that even fairly small changes in temperature can influence phenotype and postfledging survival in cavity‐nesting birds. This has the potential to affect the population dynamics of these birds in the face of ongoing climatic change, as individuals of reduced size in colder winters may suffer from decreased fitness.
Density dependence of daily activity in three ungulate species
Authors: Ramirez Juan Ignacio , Zwerts Joeri A. , van Kuijk Marijke , Iacobelli Palma , Li Xuqing , Herdoiza Natalie , Jansen Patrick A. 
Published: May 2021

AbstractDaily activity in herbivores reflects a balance between finding food and safety. The safety‐in‐numbers theory predicts that living in higher population densities increases safety, which should affect this balance. High‐density populations are thus expected to show a more even distribution of activity—that is, spread—and higher activity levels across the day. We tested these predictions for three ungulate species; red deer (Cervus elaphus), roe deer (Capreolus capreolus), and wild boar (Sus scrofa). We used camera traps to measure the level and spread of activity across ten forest sites at the Veluwe, the Netherlands, that widely range in ungulate density. Food availability and hunting levels were included as covariates. Daily activity was more evenly distributed when population density was higher for all three species. Both deer species showed relatively more feeding activity in broad daylight and wild boar during dusk. Activity level increased with population density only for wild boar. Food availability and hunting showed no correlation with activity patterns. These findings indicate that ungulate activity is to some degree density dependent. However, while these patterns might result from larger populations feeling safer as the safety‐in‐numbers theory states, we cannot rule out that they are the outcome of greater intraspecific competition for food, forcing animals to forage during suboptimal times of the day. Overall, this study demonstrates that wild ungulates adjust their activity spread and level based on their population size.