Latitudinal range shifts in Australian flying‐foxes: A re‐evaluation

Recent range shifts towards higher latitudes have been reported for many animals and plants in the northern hemisphere, and are commonly attributed to changes in climate. Relatively little is known about such changes in the southern hemisphere, although it has been suggested that latitudinal distributions of the fruit‐bats Pteropus alecto and Pteropus poliocephalus changed during the 20th century in response to climate change in eastern Australia. However, historical changes in these species distributions have not been examined systematically. In this study we obtained historical locality records from a wide range of sources (including banding and museum records, government wildlife databases and unpublished records), and filtered them for reliability and spatial accuracy. The latitudinal distribution of each species was compared between eight time‐periods (1843–1920, 1921–1950, five 10‐year intervals between 1950 and 2000, and 2001–2007), using analyses of both the filtered point data (P. alecto 870 records, P. poliocephalus 2506) and presence/absence data within 50 × 50 km grid cells. The results do not support the hypothesis that either species range is shifting in a manner driven by climate change. First, neither the northern or southern range limits of P. poliocephalus (Mackay, Queensland and Melbourne, Victoria respectively) changed over time. Second, P. alecto's range limit extended southward by 1168 km (approximately 10.5 degrees latitude) during the twentieth century (from approximately Rockhampton, Queensland to Sydney, New South Wales). Within this zone of southward expansion (25–29°S), the percentage of total records that were P. alecto increased from 8% prior to 1950 to 49% in the early 2000s, and local count data showed that its abundance increased from several hundred to more than 10 000 individuals at specific roost sites, as range expansion progressed. Pteropus alecto expanded southward at about 100 km/decade, compared with the 10–26 km/decade rate of isotherm change, and analyses of historical weather data show that the species consequently moved into recently‐colder regions than it had previously occupied. Neither climate change nor habitat change could provide simple explanations to explain P. alecto's observed rapid range shift. More generally, climate change should not be uncritically inferred as a primary driver of species range shifts without careful quantitative analyses.     

Effects of climate‐induced increases in summer drought on riparian plant species: a meta‐analysis

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Temperature‐correlated shifts in the timing of egg‐laying in House Finches Haemorhous mexicanus

Although temperature‐correlated shifts in the timing of egg‐laying have been documented in numerous bird species, the vast majority of species examined to date have been those that breed in Europe and have an animal‐based diet during breeding. However, given that the timing of breeding can be driven, either in the proximate or in the ultimate sense, by seasonal fluctuations in food availability, the relationship between temperature and laying may differ with diet. Here, we report on patterns of reproductive timing in House Finches Haemorhous mexicanus, a North American species that breeds on a primarily seed‐based diet. Analysing nest records from House Finches in California spanning more than a century, we found that egg‐laying occurred significantly earlier in warmer springs. We also found that although the timing of egg‐laying does not show long‐term changes in most of California, in the hottest region of the state (the southeast desert basin) it has advanced significantly.     

Does a long‐term shift in Wood Stork diet foreshadow adaptability to human‐induced rapid environmental change?

To preserve biodiversity, identifying at‐risk populations and developing conservation plans to mitigate the effects of human‐induced rapid environmental change (HIREC) are essential. Changes in diet, especially for food‐limited species, can aid in detecting populations being impacted by HIREC, and characterizing the quality, abundance, and temporal and spatial consistency of newly consumed food items may provide insight concerning the likelihood of a species persisting in a changing environment. We used Wood Storks (Mycteria americana) nesting in the Florida Everglades as a model system to study the possible effects of HIREC on a food‐limited population. We compared the diets of Wood Storks in 2013 and 2014 with those reported during the 1970s before major anthropogenic activities affected the Everglades system and prey availability. Wood Storks in our study consumed more large‐bodied sunfish species (Lepomis spp.), fewer native marsh fishes, and more non‐native fish species than during the 1970s. Large sunfish and non‐native fish are relatively rare in the drying pools of Everglades marshes where storks traditionally forage, suggesting that Wood Storks may be using novel foraging habitats such as created wetlands (i.e., canals and stormwater ponds). Although created wetlands have long hydroperiods conducive to maintaining large‐bodied fishes and could provide alternative foraging habitat when prey availability is reduced in natural marshes, additional studies are needed to determine the extent to which these wetlands are used by Wood Storks and, importantly, the quality of prey items potentially available to foraging Wood Storks in created wetlands.     

Continent‐scale global change attribution in European birds ‐ combining annual and decadal time scales

Species attributes are commonly used to infer impacts of environmental change on multiyear species trends, e.g. decadal changes in population size. However, by themselves attributes are of limited value in global change attribution since they do not measure the changing environment. A broader foundation for attributing species responses to global change may be achieved by complementing an attributes‐based approach by one estimating the relationship between repeated measures of organismal and environmental changes over short time scales. To assess the benefit of this multiscale perspective, we investigate the recent impact of multiple environmental changes on European farmland birds, here focusing on climate change and land use change. We analyze more than 800 time series from 18 countries spanning the past two decades. Analysis of long‐term population growth rates documents simultaneous responses that can be attributed to both climate change and land‐use change, including long‐term increases in populations of hot‐dwelling species and declines in long‐distance migrants and farmland specialists. In contrast, analysis of annual growth rates yield novel insights into the potential mechanisms driving long‐term climate induced change. In particular, we find that birds are affected by winter, spring, and summer conditions depending on the distinct breeding phenology that corresponds to their migratory strategy. Birds in general benefit from higher temperatures or higher primary productivity early on or in the peak of the breeding season with the largest effect sizes observed in cooler parts of species' climatic ranges. Our results document the potential of combining time scales and integrating both species attributes and environmental variables for global change attribution. We suggest such an approach will be of general use when high‐resolution time series are available in large‐scale biodiversity surveys.     

Late‐season snowfall is associated with decreased offspring survival in two migratory arctic‐breeding songbird species

While the effect of weather on reproduction has been studied for many years in avian taxa, the rapid pace of climate change in arctic regions has added urgency to this question by changing the weather conditions species experience during breeding. Given this, it is important to understand how factors such as temperature, rain, snowfall, and wind affect reproduction both directly and indirectly (e.g. through their effects on food availability). In this study, we ask how weather factors and food availability influence daily survival rates of clutches in two arctic‐breeding migratory songbirds: the Lapland longspur Calcarius lapponicus, a circumpolar breeder, and Gambel's white‐crowned sparrow Zonotrichia leucophrys gambelii, which breeds in shrubby habitats across tundra, boreal and continental climates. To do this, we monitored clutch survival in these two species from egg‐lay through fledge at field sites located near Toolik Field Station (North Slope, Alaska) across 5 yr (2012–2016). Our results indicate that snowfall and cold temperatures decreased offspring survival rates in both species; although Lapland longspurs were more susceptible to snowfall. Food availability, quantified by pitfall sampling and sweep‐net sampling methods, had minimal effects on offspring survival. Some climate models predict increased precipitation for the Arctic with global warming, and in the Toolik region, total snow accumulation may be increasing. Placed in this context, our results suggest that changes in snow storms with climate change could have substantial consequences for reproduction in migratory songbirds breeding in the North American Arctic.     

Global‐scale species distributions predict temperature‐related changes in species composition of rocky shore communities in Britain

Changes in rocky shore community composition as responses to climatic fluctuations and anthropogenic warming can be shown by changes in average species thermal affinities. In this study, we derived thermal affinities for European Atlantic rocky intertidal species by matching their known distributions to patterns in average annual sea surface temperature. Average thermal affinities (the Community Temperature Index, CTI) tracked patterns in sea surface temperature from Portugal to Norway, but CTI for communities of macroalgae and plant species changed less than those composed of animal species. This reduced response was in line with the expectation that communities with a smaller range of thermal affinities among species would change less in composition along thermal gradients and over time. Local‐scale patterns in CTI over wave exposure gradients suggested that canopy macroalgae allow species with ranges centred in cooler than local temperatures (‘cold‐affinity’) to persist in otherwise too‐warm conditions. In annual surveys of rocky shores, communities of animal species in Shetland showed a shift in dominance towards warm‐affinity species (‘thermophilization’) with local warming from 1980 to 2018 but the community of plant and macroalgal species did not. From 2002 to 2018, communities in southwest Britain showed the reverse trend in CTI: declining average thermal affinities over a period of modest temperature decline. Despite the cooling, trends in species abundance were in line with the general mechanism of direction and magnitude of long‐term trends depending on the difference between species thermal affinities and local temperatures. Cold‐affinity species increased during cooling and warm‐affinity ones decreased. The consistency of responses across different communities and with general expectations based on species thermal characteristics suggests strong predictive accuracy of responses of community composition to anthropogenic warming.     

Climate‐change impacts on sandy‐beach biota: crossing a line in the sand

Sandy ocean beaches are iconic assets that provide irreplaceable ecosystem services to society. Despite their great socioeconomic importance, beaches as ecosystems are severely under‐represented in the literature on climate‐change ecology. Here, we redress this imbalance by examining whether beach biota have been observed to respond to recent climate change in ways that are consistent with expectations under climate change. We base our assessments on evidence coming from case studies on beach invertebrates in South America and on sea turtles globally. Surprisingly, we find that observational evidence for climate‐change responses in beach biota is more convincing for invertebrates than for highly charismatic turtles. This asymmetry is paradoxical given the better theoretical understanding of the mechanisms by which turtles are likely to respond to changes in climate. Regardless of this disparity, knowledge of the unique attributes of beach systems can complement our detection of climate‐change impacts on sandy‐shore invertebrates to add rigor to studies of climate‐change ecology for sandy beaches. To this end, we combine theory from beach ecology and climate‐change ecology to put forward a suite of predictive hypotheses regarding climate impacts on beaches and to suggest ways that these can be tested. Addressing these hypotheses could significantly advance both beach and climate‐change ecology, thereby progressing understanding of how future climate change will impact coastal ecosystems more generally.     

Large‐scale impact of climate change vs. land‐use change on future biome shifts in Latin America

Climate change and land‐use change are two major drivers of biome shifts causing habitat and biodiversity loss. What is missing is a continental‐scale future projection of the estimated relative impacts of both drivers on biome shifts over the course of this century. Here, we provide such a projection for the biodiverse region of Latin America under four socio‐economic development scenarios. We find that across all scenarios 5–6% of the total area will undergo biome shifts that can be attributed to climate change until 2099. The relative impact of climate change on biome shifts may overtake land‐use change even under an optimistic climate scenario, if land‐use expansion is halted by the mid‐century. We suggest that constraining land‐use change and preserving the remaining natural vegetation early during this century creates opportunities to mitigate climate‐change impacts during the second half of this century. Our results may guide the evaluation of socio‐economic scenarios in terms of their potential for biome conservation under global change.     

Colour change of chemiluminescence for base‐induced decomposition of dioxetane bearing a 4‐(4‐cyanophenyl)iminomethyl‐3‐hydroxyphenyl group

A bicyclic dioxetane 1 bearing a 4‐(4‐cyanophenyl)iminomethyl‐3‐hydroxyphenyl group was found to undergo base‐induced decomposition with the accompanying emission of light, the colour of which changed depending on the base used and its concentration. When 1 was triggered with tetrabutylammonium fluoride (TBAF), 1 displayed an emission of glowing orange light. On the other hand, on treatment with a high concentration of potassium t‐butoxide complexed with 18‐crown‐6 ether, 1 afforded a flash of blue light. The mechanistic study of this unprecedented phenomenon revealed that the emission of glowing orange light was due to the normal oxido anion of keto ester 11, whereas the emission of a flash of blue light was attributed to another species that was produced by addition of a nucleophile to an iminomethyl of unstable oxido anion of dioxetane 10. Copyright © 2008 John Wiley & Sons, Ltd.     

Climate‐related genetic variation in drought‐resistance of Douglas‐fir (Pseudotsuga menziesii)

There is a general assumption that intraspecific populations originating from relatively arid climates will be better adapted to cope with the expected increase in drought from climate change. For ecologically and economically important species, more comprehensive, genecological studies that utilize large distributions of populations and direct measures of traits associated with drought‐resistance are needed to empirically support this assumption because of the implications for the natural or assisted regeneration of species. We conducted a space‐for‐time substitution, common garden experiment with 35 populations of coast Douglas‐fir (Pseudotsuga menziesii var. menziesii) growing at three test sites with distinct summer temperature and precipitation (referred to as ‘cool/moist’, ‘moderate’, or ‘warm/dry’) to test the hypotheses that (i) there is large genetic variation among populations and regions in traits associated with drought‐resistance, (ii) the patterns of genetic variation are related to the native source‐climate of each population, in particular with summer temperature and precipitation, (iii) the differences among populations and relationships with climate are stronger at the warm/dry test site owing to greater expression of drought‐resistance traits (i.e., a genotype × environment interaction). During midsummer 2012, we measured the rate of water loss after stomatal closure (transpiration_min), water deficit (% below turgid saturation), and specific leaf area (SLA, cm² g^?1) on new growth of sapling branches. There was significant genetic variation in all plant traits, with populations originating from warmer and drier climates having greater drought‐resistance (i.e., lower transpiration_min, water deficit and SLA), but these trends were most clearly expressed only at the warm/dry test site. Contrary to expectations, populations from cooler climates also had greater drought‐resistance across all test sites. Multiple regression analysis indicated that Douglas‐fir populations from regions with relatively cool winters and arid summers may be most adapted to cope with drought conditions that are expected in the future.     

Large‐scale prerain vegetation green‐up across Africa

Information on the response of vegetation to different environmental drivers, including rainfall, forms a critical input to ecosystem models. Currently, such models are run based on parameters that, in some cases, are either assumed or lack supporting evidence (e.g., that vegetation growth across Africa is rainfall‐driven). A limited number of studies have reported that the onset of rain across Africa does not fully explain the onset of vegetation growth, for example, drawing on the observation of prerain flush effects in some parts of Africa. The spatial extent of this prerain green‐up effect, however, remains unknown, leaving a large gap in our understanding that may bias ecosystem modelling. This paper provides the most comprehensive spatial assessment to‐date of the magnitude and frequency of the different patterns of phenology response to rainfall across Africa and for different vegetation types. To define the relations between phenology and rainfall, we investigated the spatial variation in the difference, in number of days, between the start of rainy season (SRS) and start of vegetation growing season (SOS); and between the end of rainy season (ERS) and end of vegetation growing season (EOS). We reveal a much more extensive spread of prerain green‐up over Africa than previously reported, with prerain green‐up being the norm rather than the exception. We also show the relative sparsity of postrain green‐up, confined largely to the Sudano‐Sahel region. While the prerain green‐up phenomenon is well documented, its large spatial extent was not anticipated. Our results, thus, contrast with the widely held view that rainfall drives the onset and end of the vegetation growing season across Africa. Our findings point to a much more nuanced role of rainfall in Africa's vegetation growth cycle than previously thought, specifically as one of a set of several drivers, with important implications for ecosystem modelling.     

Land‐use conversion and changing soil carbon stocks in China's ‘Grain‐for‐Green’ Program: a synthesis

The establishment of either forest or grassland on degraded cropland has been proposed as an effective method for climate change mitigation because these land use types can increase soil carbon (C) stocks. This paper synthesized 135 recent publications (844 observations at 181 sites) focused on the conversion from cropland to grassland, shrubland or forest in China, better known as the ‘Grain‐for‐Green’ Program to determine which factors were driving changes to soil organic carbon (SOC). The results strongly indicate a positive impact of cropland conversion on soil C stocks. The temporal pattern for soil C stock changes in the 0–100 cm soil layer showed an initial decrease in soil C during the early stage (<5 years), and then an increase to net C gains (>5 years) coincident with vegetation restoration. The rates of soil C change were higher in the surface profile (0–20 cm) than in deeper soil (20–100 cm). Cropland converted to forest (arbor) had the additional benefit of a slower but more persistent C sequestration capacity than shrubland or grassland. Tree species played a significant role in determining the rate of change in soil C stocks (conifer < broadleaf, evergreen < deciduous forests). Restoration age was the main factor, not temperature and precipitation, affecting soil C stock change after cropland conversion with higher initial soil C stock sites having a negative effect on soil C accumulation. Soil C sequestration significantly increased with restoration age over the long‐term, and therefore, the large scale of land‐use change under the ‘Grain‐for‐Green’ Program will significantly increase China's C stocks.     

Identifying drivers of species compositional change in a semi‐natural upland grassland over a 40‐year period

Question: Few long‐term studies exist with integrated vegetation and soil composition data, coupled with detailed environmental driver records. Can changes in community composition in an upland grassland be identified by revisitation after a 40‐year period and allow the main environmental drivers of change to be identified? Location: Snowdon, Wales, UK. Methods: Changes in plant community and soil composition were assessed by resurveying an upland Agrostis–Festuca grassland in 2008, 40 years after the original survey. PCA and ecological indicators were used to determine changes in plant community composition. Redundancy analysis (RDA) allowed the impact of soil chemical composition on the vegetation community to be assessed. Results: A significant shift in community composition was found between years. A 35% reduction in species richness and an increase in the grass:forb ratio, suggest significant ecosystem degradation. Indicator values suggest acidification of the community with an increased acidity preference of species recorded in 2008. However, soil pH measurements showed that soil pH had increased. RDA suggested that the main shifts in species composition were correlated with an increase in pH and a reduction in soil exchangeable base cation concentration. Clear ecosystem responses to climate, land‐use change or nitrogen enrichment were not observed. Conclusions: Shifts in vegetation and soil composition are clearly identifiable after 40 years. The shifts in community composition are consistent with ecosystem degradation due to acidification during the period between surveys. Ecological indicator values and soil chemical composition displayed differing degrees of change. Whilst soils appear to be recovering from historic effects of sulphur deposition, vegetation community composition changes appear to lag behind those in soil chemistry.     

Cross‐Sectional and Longitudinal Associations between Body Mass Index and Marriage‐Related Factors

Objective: To assess the relationship between marriage and obesity. Research Methods and Procedures: Cross‐sectional and longitudinal associations were examined between participant body mass index (BMI), spouse BMI, and participant diet and exercise habits. Results: Spouse and participant BMI and BMI changes over 2 years were significantly associated. Participant BMI was associated with higher consumption of calorie‐dense foods and lower frequency of physical activity. Participants’ eating and exercise habits were only weakly related to spouse BMI. BMI did not predict the likelihood of marriage or divorce. However, marriage was associated with a significant 2‐year weight gain and divorce with a significant 2‐year weight loss. Discussion: The results suggest that spouse similarity in BMI is at least partly due to shared environment. The observed effects of marriage and divorce on weight may be due to the influence of marriage on inducements to eat (e.g., shared meals) or on motivation for weight control.     

Predicting events in clinical trials using two time‐to‐event outcomes

In clinical trials with time‐to‐event outcomes, it is of interest to predict when a prespecified number of events can be reached. Interim analysis is conducted to estimate the underlying survival function. When another correlated time‐to‐event endpoint is available, both outcome variables can be used to improve estimation efficiency. In this paper, we propose to use the convolution of two time‐to‐event variables to estimate the survival function of interest. Propositions and examples are provided based on exponential models that accommodate possible change points. We further propose a new estimation equation about the expected time that exploits the relationship of two endpoints. Simulations and the analysis of real data show that the proposed methods with bivariate information yield significant improvement in prediction over that of the univariate method.     

Seasonal temperature and precipitation regulate brook trout young‐of‐the‐year abundance and population dynamics

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Temporal response of soil organic carbon after grassland‐related land‐use change

The net flux of CO₂ exchanged with the atmosphere following grassland‐related land‐use change (LUC) depends on the subsequent temporal dynamics of soil organic carbon (SOC). Yet, the magnitude and timing of these dynamics are still unclear. We compiled a global data set of 836 paired‐sites to quantify temporal SOC changes after grassland‐related LUC. In order to discriminate between SOC losses from the initial ecosystem and gains from the secondary one, the post‐LUC time series of SOC data was combined with satellite‐based net primary production observations as a proxy of carbon input to the soil. Globally, land conversion from either cropland or forest into grassland leads to SOC accumulation; the reverse shows net SOC loss. The SOC response curves vary between different regions. Conversion of cropland to managed grassland results in more SOC accumulation than natural grassland recovery from abandoned cropland. We did not consider the biophysical variables (e.g., climate conditions and soil properties) when fitting the SOC turnover rate into the observation data but analyzed the relationships between the fitted turnover rate and these variables. The SOC turnover rate is significantly correlated with temperature and precipitation (p < 0.05), but not with the clay fraction of soils (p > 0.05). Comparing our results with predictions from bookkeeping models, we found that bookkeeping models overestimate by 56% of the long‐term (100 years horizon) cumulative SOC emissions for grassland‐related LUC types in tropical and temperate regions since 2000. We also tested the spatial representativeness of our data set and calculated SOC response curves using the representative subset of sites in each region. Our study provides new insight into the impact grassland‐related LUC on the global carbon budget and sheds light on the potential of grassland conservation for climate mitigation.