Search

Natural populations are composed of individuals that vary in their morphological traits, timing and interactions. The distribution of a trait can be described by several dimensions, or mathematical moments—mean, variance, skew and kurtosis. Shifts in the distribution of a trait across these moments in response to environmental variation can help to reveal which trait values are gained or lost, and consequently how trait filtering processes are altering populations. To examine the role and drivers of intraspecific variation within a trait filtering framework, we investigate variation in body size among five wild bumblebee species in the Colorado Rocky Mountains. First, we examine the relationships between environmental factors (climate and floral food resources) and body size distributions across bumblebee social castes to identify demographic responses to environmental variation. Next, we examine changes in the moments of trait distributions to reveal potential mechanisms behind intraspecific shifts in body size. Finally, we examine how intraspecific body size variation is related to diet breadth and phenology. We found that climate conditions have a strong effect on observed body size variation across all distributional moments, but the filtering mechanism varies by social caste. For example, with earlier spring snowmelt queens declined in mean size and became negatively skewed and more kurtotic. This suggests a skewed filter admitting a greater frequency of small individuals. With greater availability of floral food resources, queens increased in mean size, but workers and males decreased in size. Observed shifts in body size variation also correspond with variation in diet breadth and phenology. Populations with larger average body size were associated with more generalized foraging in workers of short‐tongued species and increased specialization in longer‐tongued workers. Altered phenological timing was associated with species‐ and caste‐specific shifts in skew. Across an assemblage of wild bumblebees, we find complex patterns of trait variation that may not have been captured if we had simply considered mean and variance. The four‐moment approach we employ here provides holistic insight into intraspecific trait variation, which may otherwise be overlooked and reveals potential underlying filtering processes driving such variation within populations. [ABSTRACT FROM AUTHOR]

Popular tourism destinations are not insulated from climate change variability and vulnerability. Conversely, these destinations also contribute to climate change. Although several studies have investigated the climate change-tourism nexus, there remains limited knowledge regarding tourist perceptions of climate change on popular African destinations. This study examines tourist perceptions of climate change at the Sun City Resort, a popular destination in South Africa attracting both domestic and international tourists all year round. Data were generated from a survey of 278 tourist participants. The data were analysed in JMP Pro generating descriptive statistics to determine variable and response frequencies, and Structural Equation Modelling (SEM) to examine the relationships, mediations, and associations among key constructs. The results reveal significant associations among climate change awareness, climate change experiences, climate change impacts, and response strategies. Most tourists are familiar with climate change and its existential and potential impacts on the resort. The most prominent weather events include heatwaves, heavy rainfall, and droughts. The impacts include water scarcity, disruption of recreational activities, and destruction of habitats. Low carbon transport systems and green accommodation facilities, carbon friendly activities, investing in climate disaster early warning systems, climate-proofed infrastructure, ensuring facilities and upgrading of disaster rescue operations were highlighted as suitable response strategies. The study concludes that tourists are generally conscious of climate change, and they have knowledge of the necessary actions to ensure popular destination suitability in the face of climate change. The study opens the possibility for crafting destination specific climate action plans that promote destination sustainability.

In this review we assess past and current trends in the use of testate amoebae in peatland science, concentrating mainly on studies conducted in northern peatlands. We also discuss the potential of testate amoebae for future research. Testate amoebae are unicellular protists that are covered by protective tests which are easily identifiable and are stored in peat over millennia. Testate amoeba species are specialised to live in a thin water film coating the mosses that creates different microhabitats for species varying in size and shape. They are therefore considered good indicators for hydrology, in particular. In peatlands they represent dominant consumers in the microbial food web, but mixotrophic species also contribute to photosynthesis. Due to their functional role in peatland microbial communities, and as related to challenges in identification and taxonomy, there has been increasing interest towards understanding their functional traits. We suggest that more fundamental research about testate amoeba taxonomy, autecology and functional ecology is needed, but at the same time we can conclude that testate amoebae are a useful tool for contemporary topics in peatland science, including climate-induced changes in peatland functioning and peatland restoration.

In this review we assess past and current trends in the use of testate amoebae in peatland science, concentrating mainly on studies conducted in northern peatlands. We also discuss the potential of testate amoebae for future research. Testate amoebae are unicellular protists that are covered by protective tests which are easily identifiable and are stored in peat over millennia. Testate amoeba species are specialised to live in a thin water film coating the mosses that creates different microhabitats for species varying in size and shape. They are therefore considered good indicators for hydrology, in particular. In peatlands they represent dominant consumers in the microbial food web, but mixotrophic species also contribute to photosynthesis. Due to their functional role in peatland microbial communities, and as related to challenges in identification and taxonomy, there has been increasing interest towards understanding their functional traits. We suggest that more fundamental research about testate amoeba taxonomy, autecology and functional ecology is needed, but at the same time we can conclude that testate amoebae are a useful tool for contemporary topics in peatland science, including climate-induced changes in peatland functioning and peatland restoration. [ABSTRACT FROM AUTHOR]

Ectotherms utilise a complex array of behavioural and physiological mechanisms to cope with variation in suboptimal thermal environments. However, these mechanisms may be insufficient for population persistence under contemporary climate change, resulting in a greater need to understand how local populations respond to geographic variation in climate. In this study, we explored the potential for local adaptation and acclimation in thermal traits and behaviours using wild and captive populations of a small agamid lizard (the jacky lizard, Amphibolurus muricatus). We predicted that wild lizards from a high elevation site would have cooler thermal preferences compared to those at low elevation sites to match the more restricted thermal resources at higher, cooler elevations. We additionally explored whether variation in thermal traits was due to recent acclimation or fixed population differences, such as due to developmental plasticity or local adaptation. In contrast to our predictions, we found high-elevation lizards began panting at higher temperatures and had higher thermal preferences relative to lower elevation lizards. When allowed to bask freely, there was no difference in the intensity of basking or daily duration of time spent basking between lizards from different elevations. Although the high-elevation lizards appeared to show stronger acclimation to recent air temperatures compared to low-elevation lizards, this difference was not significant. Similarly, captive lizards acclimated under long and short basking regimes showed no major differences in thermal traits or basking behaviour. Our results are consistent with the presence of counter-gradient variation in thermal phenotypes of lizards, and suggest that these are driven by local adaptive responses or developmental effects rather than recent acclimation. • We found a counter-gradient elevational pattern in thermal traits in an Australian lizard. • Lizards at high elevations had hotter thermal traits than at low elevations. • Thermal preferences and panting threshold demonstrated the same pattern. • Population differences were not driven by recent climate. [ABSTRACT FROM AUTHOR]

Solar photovoltaic (PV) technology is widely regarded as a significant and sustainable renewable energy option to fight against climate change.Accordingly, it is important to explore the potential of greenhouse gases (GHGs) mitigation and temperature benefits by substituting PV-generated power for coal-fired electricity. This necessity becomes particularly clear given that China hascommitted itself to a carbon emissions peak around 2030. Based on an integrated energy-economy-environmental model and a simple climate response model, we reach the following conclusions: (1) By restraining the cumulative GHGs emissions space within 255 GtCO 2eq till 2050, PV solar promises to dominate GHGs mitigation, with the highest contribution reaching 64.67%. (2) Under the moderate emissions-control case, China will achieve its emissions peak target, with solar energy substitution relieving the nation׳s dependence on coal. (3) The highest radiative forcing and temperature benefits yieldedthrough replacing coal-generated power with solar power is around 20% and 11.05%, respectively. (4) Finally, it is not too costly to gain such benefits: at most, the accumulated economic cost would be 102.14 trillion Yuanuntil 2050, accounting for less than 3% of the accumulated GDP. [ABSTRACT FROM AUTHOR]

Subtropical forests in montane ecosystems grow under a wide range of environmental conditions. However, little is known about the growth responses of subtropical trees to climate along ecological gradients. To assess how, and to what extent climate controls tree growth, we analyzed tree responses to climate for 15 chronologies from 4 different species ( Schinopsis lorentzii, Juglans australis, Cedrela lilloi, Alnus acuminata) across a variety of environments in subtropical forests from northwestern Argentina (22-28°S, 64-66°W). Using correlation and principal component analysis, site and species differences in tree-growth responses to precipitation and temperature were determined along the elevation gradient from the dry-warm Chaco lowlands to the wet-cool montane Yungas. Our results show that species responses differ according to the severity in climate conditions along the elevation gradient. At sites with unfavorable conditions, mainly located at the extremes of the environmental gradient, responses of different species to climate variations are similar; in contrast, at sites with relatively mild conditions, tree growth displays a large variety of responses reflecting differences in both local environmental conditions and species physiology. Our research suggests that individualistic responses to environmental variability would determine differences in the type and timing of the responses of dominant trees to climate, which ultimately may shift species' assemblages in montane subtropical regions of South America under future climate changes. [ABSTRACT FROM AUTHOR]

Abstract: As in all parts of the globe, rapid climate change in Australia will have significant negative impacts on biodiversity. It also will interact with pre-existing stressors such as native vegetation clearing, altered natural disturbance regimes and invasive species – all of which already have major negative effects on biota in Australia. Strategies to reduce climate change impacts on Australian biodiversity include a mixture of mitigation and adaptation actions (sensu) such as: (1) significantly reducing greenhouse gas emissions, (2) ensuring bio-diverse carbon capture, (3) better tackling pre-existing stressors on biodiversity, (4) better preparing for the effects of major natural disturbances, (5) significantly improving off-reserve conservation efforts including fostering appropriate connectivity, and (6) enhancing the existing reserve system by making it more comprehensive, adequate and representative. The first strategy above demands a global response otherwise major mitigation attempts in Australia that are not paralleled elsewhere around the world will have little effect on climate change and, in turn, contribute little to enhanced biodiversity conservation. Strategies 2–6 demand multi-scaled responses, particularly at a regional level, given the major regional differences in direct climate change impacts and their interactions with pre-existing regional stressors. Well developed multi-scaled conservation plans to implement these strategies currently do not exist, nor do appropriate institutional arrangements and capacities. Institutional reforms are urgently needed in Australia to develop the land management, monitoring and regional response capabilities required to conserve biodiversity on a continent already significantly modified. [Copyright &y& Elsevier]

Approximately 185,000 forest inventory and ecological plots from both USA and Canada were used to predict the contemporary distribution of western larch (Larix occidentalis Nutt.) from climate variables. The random forests algorithm, using an 8-variable model, produced an overall error rate of about 2.9 %, nearly all of which consisted of predicting presence at locations where the species was absent. Genetic variation among 143 populations within western larch's natural distribution was predicted from multiple regression models using variables describing the climate of the seed source as predictors and response data from two separate genetic tests: 1) 15-year height at a field site in British Columbia, Canada, and, 2) two principal components of 8 variables describing growth, disease tolerance, and phenology of 6-year-old trees in a test in Idaho, USA. Presence and absence of the species and genetic variation within the species were projected into future climates provided by three General Circulation Models and two scenarios. Although the projections described pronounced impacts on the species and its populations, concurrence among the six projections pinpointed areas where the probability would be high that the future climate would be suitable for western larch. Concurrence among projections also was used to locate those sources of seed that should be best attuned genetically to future climates. The procedures outline a logical approach for developing management strategies for accommodating climate-change while taking into account the variability imposed by the differences among climatic estimates. [ABSTRACT FROM AUTHOR]

Abstract: A bioclimate model predicting the presence or absence of aspen, Populus tremuloides, in western USA from climate variables was developed by using the Random Forests classification tree on Forest Inventory data from about 118,000 permanent sample plots. A reasonably parsimonious model used eight predictors to describe aspen''s climate profile. Classification errors averaged 4.5%, most of which were errors of commission. The model was driven primarily by three variables: an annual dryness index, the ratio of summer to annual precipitation, and an interaction of growing season precipitation with the summer–winter temperature differential. Projecting the contemporary climate profile into the future climate provided by three General Circulation Models and two scenarios (SRES A2 and either B1 or B2) suggested that the area occupied by the profile should diminish rapidly over the course of the century, 6–41% by the decade surrounding 2030, 40–75% for that surrounding 2060, and 46–94% for 2090. The relevance of the climate profile to understanding climate-based responses is illustrated by relating trends in climate to the recent incidence of sudden aspen dieback that has plagued portions of the aspen distribution. Of the eight variables in the profile, four reached extreme values during 2000–2003, the period immediately preceding the appearance of damage in aerial surveys. [Copyright &y& Elsevier]

Abstract: There are very few studies on the effects of temporal changes in soil properties on ecosystem engineers in UK soils. This study addresses this lack by presenting earthworm diversity data from a six-year seasonality study comprising 72 monthly samples from the litter and soil of pasture woodland in the New Forest, southern England. These data were analysed in the context of soil moisture and soil temperature, key factors affecting earthworm abundance, and factors likely to be strongly affected by future climate change. The data for the whole period were analysed using non-parametric regression and an additive model used to separate within-year and between-year effects. Seasonal patterns are present for all the common species, generally with a maximum in March and a minimum in September. A majority of the five commonest species show a strong decline in abundance during the two extremely dry periods (2002–2003 and 2006). In sharp contrast, the same species showed a relative increase during the very wet summer and autumn of 2007. There was, however, no significant overall trend in either the climate data or the earthworm species data. The epigeic species, Dendrobaena octaedra, showed the largest decline in the driest months which caused a crash to the point where there were no adults sampled during the four dry summer months of 2003. A second congeneric species, Dendrobaena attemsi, also epigeic, appears to have invaded the woodland during the six year period and is increasing rapidly in abundance. This may indicate the start of a shift in the distribution of the two species, as D. octaedra generally has a northern European distribution and is frost-tolerant, while D. attemsi has a southern European distribution and is more drought-tolerant. In contrast, the very wet summer of 2007 seems to have damped the usual periodic seasonal oscillations in earthworm numbers. Endogeic worm species do not show the D. octaedra seasonal pattern as obviously, probably because these species are able to move more freely through the soil and because they are able to aestivate. These changes are likely to be due to a combination of human movement of earthworms (e.g. D. attemsi) and variations in local climate. [Copyright &y& Elsevier]

As part of the development work of the Chinese new regional climate model (RIEMS), the radiative process of black carbon (BC) aerosols has been introduced into the original radiative procedures of RIEMS, and the transport model of BC aerosols has also been established and combined with the RIEMS model. Using the new model system, the distribution of black carbon aerosols and their radiative effect over the China region are investigated. The influences of BC aerosole on the atmospheric radiative transfer and on the air temperature, land surface temperature, and total rainfall are analyzed. It is found that BC aerosols induce a positive radiative forcing at the top of the atmosphere (TOA), which is dominated by shortwave radiative forcing. The maximum radiative forcing occurs in North China in July and in South China in April. At the same time, negative radiative forcing is observed on the surface. Based on the radiative forcing comparison between clear sky and cloudy sky, it is found that cloud can enforce the TOA positive radiative forcing and decrease the negative surface radiative forcing. The responses of the climate system in July to the radiative forcing due to BC aerosols are the decrease in the air temperature in the middle and lower reaches of the Changjiang River and Huaihe area and most areas of South China, and the weak increase or decrease in air temperature over North China. The total rainfall in the middle and lower reaches of the Changjiang River area is increased, but it decreased in North China in July. [ABSTRACT FROM AUTHOR]

• The masting habit and growth of stone pine were studied for individuals and stands. • A higher regional synchrony of ring-with compared with that of cone yield was found. • Large cone yields did not penalise growth during the year of main cone growth. • High positive correlations between growth and cone yield were found lagged 3 years. • Support is given for weather cueing as main masting mechanism of this species. Trade-offs between life-history traits are common in plants, and those involving growth and reproduction may be evident during mast years. The nutlike seeds of the stone pine (Pinus pinea L.) stand out among the most appreciated Mediterranean forest products, but its lengthy reproductive cycle makes the identification of masting mechanisms challenging. In the Spanish Northern Plateau, stone pine woodlands are managed as multifunctional forests. Here, we investigated whether timber and nut production are compatible goals in the region. Temporal ring-width and cone yield patterns were characterised in five monospecific stands since 1960. At tree level, we found an equivalent allocation of resources to reproductive and non-reproductive (aboveground) biomass for an average year, but harvest index exceeded 80% during mast years. These large yields, however, did not impose a penalty on aboveground biomass increment. Regionally, we reported a slightly larger magnitude of high-frequency synchronous growth (â = 0.50) compared with that of reproduction (â = 0.42), which is important to contextualise the ecological and economical relevance of masting for the species. By investigating growth-yield interannual dynamics, we found that both traits were strongly and positively correlated, although with a 3-year lag. Therefore, years favouring a high growth coincided with large conelet emergences leading to abundant seed rains to occur three years later, which pointed to key environmental drivers common to both traits. Actually, radial growth and reproduction partly responded to the same climate factors, with climate three years before seed rain being related to masting in a similar way as it was related to ring-width of this same year. Our results provide evidence for the proposed link between masting and growth, and suggest that resources are not diverted from growth during cone filling in stone pine. We conclude that timber production and nut production are perfectly compatible in this species. [ABSTRACT FROM AUTHOR]

• Two daily patterns of winter circulation responses to aerosols are identified. • Daily patterns are linked to tropical rainfall and extratropical transient eddies. • Seasonal mean changes can arise from certain daily response patterns. Anthropogenic aerosols (AA) have significantly caused anomalous winter mean atmospheric circulation over the Northern Hemisphere, but the main daily patterns of winter large-scale circulation change are not well understood. Here a self-organizing map analysis is applied to identify the leading patterns in AA-induced winter daily geopotential height (Z) anomaly fields simulated by three atmospheric general circulation models, with a focus on fast adjustments. Two winter daily circulation response patterns with a synoptic time scale are found: one pattern shows concurring Z anomalies over North America and North Asia with the same sign and the Bering Sea seeing the opposite, resembling the Asia–Bering–North American teleconnection; while the other is the Arctic Oscillation-like pattern with similar Z anomalies over North Pacific and North Atlantic and the opposite over the Arctic region. The AA-induced anomalous precipitation over the tropics and anomalous synoptic eddy activities over the extratropical oceans concur to support and maintain these circulation anomaly patterns. The winter-mean climate responses to AA can be understood as a result of these daily anomaly patterns, especially over the higher latitudes. Specifically, the associated changes in surface air temperature (SAT) over the mid-high latitudes are caused by the AA-driven meridional movements of polar (cold and dry) airmass and midlatitude (warm and moist) airmass in the regions, mainly through the relevant surface downward longwave radiation. This study highlights the role of AA in altering daily weather patterns, which is not sufficiently captured by seasonal mean responses. [ABSTRACT FROM AUTHOR]