Shifting nonbreeding distributions of migratory fauna in relation to climatic change

The distributions of eight out of nine common species of waders (Charadrii) overwintering on UK estuaries have changed in association with recent climate change. These birds represent a high proportion of various populations from breeding grounds as far apart as Greenland to the west to high‐arctic Russia to the east. During warmer winters, smaller proportions of seven species wintered in south‐west Britain. The distributions of the smaller species show the greatest temperature dependence. The opposite was found for the largest species and no relationship was found for a particularly site‐faithful species. In north‐west Europe, the winter isotherms have a broadly north to south alignment, with the east being colder than the west. The average minimum winter temperatures across the UK having increased by about 1.5°C since the mid‐1980s, the temperatures on the east coast during recent winters have been similar to those of the west coast during the mid‐1980s. On average, estuaries on the east and south coasts of Britain have muddier sediments than those on the west coast and thus support a higher biomass of the invertebrate prey of waders. We suggest that, with global climatic change, the advantage gained by waders wintering in the milder west to avoid cold weather‐induced mortality is diminished. Consequently, more choose to winter in the east and thus benefit from better foraging opportunities. The implications of these results are considered in terms of a site‐based approach to wildlife protection used in Europe and elsewhere.     

Designing ecological climate change impact assessments to reflect key climatic drivers

Identifying the climatic drivers of an ecological system is a key step in assessing its vulnerability to climate change. The climatic dimensions to which a species or system is most sensitive – such as means or extremes – can guide methodological decisions for projections of ecological impacts and vulnerabilities. However, scientific workflows for combining climate projections with ecological models have received little explicit attention. We review Global Climate Model (GCM) performance along different dimensions of change and compare frameworks for integrating GCM output into ecological models. In systems sensitive to climatological means, it is straightforward to base ecological impact assessments on mean projected changes from several GCMs. Ecological systems sensitive to climatic extremes may benefit from what we term the ‘model space’ approach: a comparison of ecological projections based on simulated climate from historical and future time periods. This approach leverages the experimental framework used in climate modeling, in which historical climate simulations serve as controls for future projections. Moreover, it can capture projected changes in the intensity and frequency of climatic extremes, rather than assuming that future means will determine future extremes. Given the recent emphasis on the ecological impacts of climatic extremes, the strategies we describe will be applicable across species and systems. We also highlight practical considerations for the selection of climate models and data products, emphasizing that the spatial resolution of the climate change signal is generally coarser than the grid cell size of downscaled climate model output. Our review illustrates how an understanding of how climate model outputs are derived and downscaled can improve the selection and application of climatic data used in ecological modeling.     

Simulating vegetation shifts in north-eastern Mediterranean mountain forests under climatic change scenarios

Aim  To explore potential shifts in vegetation and fire regime in some dominant forest types in the north-eastern part of the Mediterranean basin under climate change.
Location  Two altitudinal gradients in the continental part of Greece.
Methods  We developed a forest gap dynamics simulator that provides feedback from the stand to its water balance and flammability status. The model is used to simulate vegetation dynamics in two mountainous areas, currently found under different aridity conditions. Two climatic change scenarios (Intergovernmental Panel on Climate Change A1 and B2) were applied to explore differences in the response of the established forest types. In addition we explicitly accounted for the role of fire, under both current and altered climate patterns.
Results  Fire was identified to play a significant role in low-altitude sites. Its significance increased with the severity of the climate change scenario. Elevational shifts of the dominant species were simulated for each site, while in some cases these changes were associated with a shorter fire cycle and a frequent resetting of processes of vegetation change.
Main conclusions  Our simulations suggest a greater vulnerability of mountainous Mediterranean drier areas regarding compositional alteration and flammability trends. Changes in vegetation could take place through both a discrete and synergistic realization of changes in the drought stress and fire frequency.     

A demographic approach to study effects of climate change in desert plants

Desert species respond strongly to infrequent, intense pulses of precipitation. Consequently, indigenous flora has developed a rich repertoire of life-history strategies to deal with fluctuations in resource availability. Examinations of how future climate change will affect the biota often forecast negative impacts, but these—usually correlative—approaches overlook precipitation variation because they are based on averages. Here, we provide an overview of how variable precipitation affects perennial and annual desert plants, and then implement an innovative, mechanistic approach to examine the effects of precipitation on populations of two desert plant species. This approach couples robust climatic projections, including variable precipitation, with stochastic, stage-structured models constructed from long-term demographic datasets of the short-lived Cryptantha flava in the Colorado Plateau Desert (USA) and the annual Carrichtera annua in the Negev Desert (Israel). Our results highlight these populations'' potential to buffer future stochastic precipitation. Population growth rates in both species increased under future conditions: wetter, longer growing seasons for Cryptantha and drier years for Carrichtera. We determined that such changes are primarily due to survival and size changes for Cryptantha and the role of seed bank for Carrichtera. Our work suggests that desert plants, and thus the resources they provide, might be more resilient to climate change than previously thought.     

Evolutionary and ecological response of pocket gophers (Thomomys talpoides) to late-Holocene climatic change

Late-Holocene evolutionary and ecological response of pocket gophers ( Thomomys talpoides ) and other species to climatic change is documented by mammalian fossils from Lamar Cave, a palaeontological site in northern Yellowstone National Park. Pocket gophers illustrate ecological sensitivity to a series of mesic to xeric climatic excursions in the sagebrush-grassland ecotone during the last 3200 years, increasing in abundance during mesic intervals, and declining in abundance during xeric intervals. Four other small mammal taxa (Microtus sp., Peromyscus maniculatus, Neotoma cinerea and Spermophilus armatus) also show response to climatic change, increasing or decreasing in abundance in accordance with their preferred habitat requirements. To determine evolutionary response to climate, two craniodental characters for the northern pocket gopher ( Thomomys talpoides ) are investigated in modern representatives within a 400 km radius of Lamar Cave and then tracked through the time spanned by the fossils. One morphologic character shows that variation in body size, primarily a plastic response to the environment, demonstrates few taxonomically consistent patterns of geographic variation across 39 modern localities. In contrast, the other character indicates genetic relatedness within subspecies. Stasis in the genetically controlled character indicates that the same subspecies of pocket gopher ( T. talpoides tenellus ) has occupied northern Yellowstone for at least 3200 years. However, T. t. tenellus does show plastic response to climatic change because pocket gophers during the Medieval Warm Period were smaller than at any other time spanned by the deposit.     

A comparative study of the tolerance of salt marsh plants to manganese

Summary Salicornia europaea, Puccinellia maritima, Triglochin maritima, Aster tripolium, Plantago maritima, Armeria maritima, Juncus gerardii andFestuca rubra, collected as seed from a salt marsh at Portaferry, County Down, were grown on saline (340 mM NaCl) and non saline nutrient solutions at five concentrations of manganese sulphate (0.025–10.0 mM). After an eight week growing period, shoot and root yields and the concentrations of sodium, potassium, calcium and manganese in the shoots were determined.Except forS. europaea the saline treatments had a strongly limiting effect on plant growth. Each of the species investigated showed a degree of tolerance to high concentrations of manganese which was similar to that of calcifuge species and plants characteristic of waterlogged sand dune slack communities, but which was very much greater than that ofArrhenatherum elatius a species usually excluded from acidic soils. There was little evidence to support the hypothesis that tolerance of high manganese concentrations was correlated with the position of the experimental plants in the salt marsh ecotone or that the manganese nutrition of halophytic and glycophytic marsh species differs. Whilst manganese uptake increased proportionally with solution manganese concentration, there were few other major effects of manganese on the balance of shoot cation concentrations in the plants investigated. Both antagonistic and synergistic effects of sodium on manganese uptake were recorded for different species.     

A comparative study of distant hybridization in plants and animals

Distant hybridization refers to crosses between two different species, genera, or higher-ranking taxa, which can break species limits, increase genetic variation, and combine the biological characteristics of existing species. It is an important way of creating genetic variation, fertile strains, and excellent characteristics in new strains and populations. Combining analyses and summaries from many inter-related documents in plants and animals, both domestic and international, including examples and long-standing research on distant hybridization in fish from our laboratory, we summarize and compare the similarities and differences in plant and animal distant hybridization. In addition, we analyze and review the biological characteristics of their different ploidy progenies and the possible causes of disparity in survival rates. Mechanisms of sterility in animal and plant distant hybrids are also discussed, and research methods for the study of biological characteristics of hybrids, including morphology, cytology,and molecular cytogenetics are presented. This paper aims to provide comprehensive research materials and to systematically compare the general and specific characteristics of plant and animal hybrids with regards to reproduction, genetics, growth traits,and other biological characteristics. It is hoped that this paper will have great theoretical and practical significance for the study of genetic breeding and biological evolution of plant and animal distant hybridization.     

A comparative study of ciliated protozoa communities in activated-sludge plants

Abstract: Ciliated protozoa present in ten activated sludge plants at Madrid (Spain) were identified. The abundance of key groups of ciliates was determined at each plant; attached ciliates made up the most abundant and representative group. Multivariate statistical analysis was employed to study relationships between ciliates and both the physico-chemical and operational parameters of the plants. Partial correlation analysis revealed: (1) The indicator value of attached ciliates in assessing management and performance of the activated sludge process, (2) the relationship of swimming ciliates with short-aged sludges and lower quality effluents and (3) the direct association between swimming-crawling ciliates and bad settlement conditions of the sludge. Factor analysis showed the associations of the most frequent species of ciliates with the operational parameters of the plants, suggesting the indicator value of some of the species: Vorticella striata was related with poor quality of effluent; Aspidisca cicada with stable plant conditions, and Litonotus lamella with a deficiently settling sludge.     

A comparative analysis of morphological and ecological characters of European aphids and lycaenids in relation to ant attendance

Ants are a major environmental factor for many insect species. For example, aphids and lycaenids have evolved an array of associations with ants ranging from obligate myrmecophily to the avoidance of contact. Here we (1) analyze the predictive power of different ecological and morphological traits for explaining the strength of the association between ants and aphids/lycaenids and (2) contrast different taxonomic levels with respect to the variance explained by ant attendance. Data come from a literature survey including 112 species of aphids and 103 species of lycaenids from Europe. For aphids, feeding on woody plant parts is positively associated with ant attendance, while a high degree of mobility, feeding in isolation, and the possession of wings in the adult stage are negatively associated with ant attendance. In lycaenids, feeding on inflorescences and feeding on Fabaceae host plants is closely associated with ant attendance, while living in forests bears a smaller likelihood to establish mutualistic relationships. Body size always appeared to be a poor predictor for the degree of ant attendance. Overall, in both insect groups less than 10% of the variation in the ecological traits recorded is explained by the different modes of ant association. When decomposing the variance in traits explained by ant attendance at different taxonomic levels, aphids and lycaenids show contrasting results. In aphids, most variance in the degree of ant attendance is explained at the subfamily level and least at the species level. The opposite is true for lycaenids, where most variance is explained at the lowest taxonomic level. Possible mechanisms explaining these different patterns of associations with ants are suggested.     

Analysis of phenotypic change in relation to climatic drivers in a population of Soay sheep Ovis aries

Climatic change has frequently been identified as a key driver of change in biological communities. These changes can take the form of alterations to population dynamics, phenotypic characters, genetics and the life history of organisms and can have impacts on entire ecosystems. This study presents a novel investigation of how changes in a large scale climatic index, the North Atlantic Oscillation (NAO) can influence population dynamics and phenotypic characters in a population of ungulates. We use an integral projection model combined with actual climate change predictions to project future body size distributions for a population of Soay sheep Ovis aries. The climate change predictions used to direct our model projections were taken from published results of climate models, covering a range of different emissions scenarios. Our model results showed that for positive changes in the mean NAO large population declines occurred simultaneously with increases in mean body weight. The exact direction and magnitude of changes to population dynamics and character distributions were dependent on the greenhouse gas emissions scenario and model used to predict the NAO. This study has demonstrated how integral projection models can use outputs of climate models to direct projections of population dynamics and phenotypic character distributions. This approach allows the results of this study to be placed within current climate change research. The nature of integral projection models means that this methodology can be easily applied to other populations. The model can also be easily updated when new climate change predictions become available, making it a useful tool for understanding potential population level responses to climatic change. Synthesis Understanding how changes in climate affect biological communities is a key component in predicting the future form of populations. Utilising a novel approach that incorporates climatic drivers (in this instance the winter North Atlantic Oscillation) into an integral projection model framework, we predict future Soay sheep dynamics under specific climate change scenarios. Tracking quantitative trait distributions and life history metrics, our results predict declining population size and increasing body weight for an increasingly positive winter North Atlantic Oscillation index, as predicted by climate models. This has important implications for future wildlife management strategies and linking demographic responses to climate change.     

Pollinator-driven ecological speciation in plants: new evidence and future perspectives

Background

The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation.

Scope

This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of ‘pollination ecotypes‘, (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies further illustrate innovative experimental approaches, and they employ modern tools in genetics and floral trait quantification. Future advances to the field require better quantification of selection through male fitness and pollinator isolation, for instance by exploiting next-generation sequencing technologies. By combining these new tools with strategically chosen study systems, and smart experimental design, we predict that examples of pollinator-driven speciation will be among the most widespread and compelling of all cases of ecological speciation.     

Statistical approaches to interpreting diversity patterns in the Norwegian mountain flora

The richness of Norwegian mountain plants in 75 grid squares is mapped from published distributional data for 109 species. Eleven explanatory variables representing bedrock geology, geography and topography, climate, and history (relative abundance of unglaciated areas) Tor each square are used in multiple regression analysis with associated Monte Carlo permutation tests to find statistically significant predictor variables for species richness. The variance in richness explained by the four major groups or explanatory variables is established by (partial) multiple regression analysis in which the groups of predictors are entered in different orders. The variance in species richness explained by the predictor variables is partitioned into four independent components. A predictive model for species richness using partial least squares regression and all explanatory variables has a coefficient of determination (R²) of 0.79. The statistical results consistently show that species-richness patterns are well explained by modern-day factors such as climate, geology, elevation, and geography without recourse to historical variables. The nunatak hypothesis of plant survival on unglaciated areas within Norway does not explain the observed richness patterns when modern ecological factors are considered first. The nunatak hypothesis thus appears to be redundant, a view supported by recent palaeobotanical. biosystematical, and evolutionary studies.     

未来气候变化对中国天然橡胶种植气候适宜区的影响

全球气候变暖将严重影响中国天然橡胶种植的气候适宜区分布.根据影响中国橡胶种植的5个主导气候因子,即最冷月平均温度、极端最低温度平均值、月平均温度≥18 ℃月份、年平均气温和年平均降水量,基于最大熵MaxEnt模型,利用1981—2010年全国气候数据和RCP4.5情景的气候预估,分析了1981—2010、2041—2060、2061—2080年中国天然橡胶种植的气候适宜区变化.结果表明： 随着未来气候变化,2041—2060和2061—2080年中国天然橡胶的种植气候适宜区范围总体呈北扩趋势,对橡胶树北移有利. 2041—2060、2061—2080年中国天然橡胶气候适宜区总面积较1981—2010年呈增长趋势,高适宜区和中适宜区的面积均有增加趋势,而低适宜区面积呈减少趋势.局部区域气候适宜性发生明显变化：云南的橡胶主产区的适宜区总面积减少,其中,云南省的景洪、勐腊等地将由现在的高适宜区转变为中适宜区,海南岛及广东雷州半岛的橡胶种植高适宜区面积明显增加,在台湾岛出现了新的橡胶种植低适宜区等.     

七种阔叶常绿植物叶片的生态解剖学研究

对 7种常绿阔叶植物叶片的解剖学特征的观察结果表明 ,它们的叶片在结构上均表现出典型的旱生特点 :异面叶 ,上表皮细胞较厚且排列紧密 ,具发达的角质膜 ,无气孔器分布 ,下表皮细胞较小 ,气孔器密度较大 ;栅栏组织细胞层数较多 ,排列紧密 ,海绵组织细胞排列极其疏松 ,并形成通气组织 ;中脉及其输导组织和机械组织发达。越冬叶和越夏叶在解剖结构上存在一定的差异 :前者在角质膜 ,叶片厚度和栅栏组织厚度等方面比后者厚 ,而在气孔密度和输导组织方面则比后者略有减少或不发达。这些差异 (发育可塑性 )是常绿阔叶植物适应冬、夏季截然不同的两种生境 (生境的时间异质性 )的表现形式     

Responses of tree populations to climatic change

The influence of climate on the population dynamics of trees must be inferred from indirect sources of information because the long lifespans of trees preclude direct observation of population growth and decline. Important insights about these processes come from 1) observations of the life histories and ecologies of trees in contemporary forests, 2) evidence of recent treeline movements in remote areas unaffected by human disturbance, and 3) results of experiments performed on forest simulation models. Each line of evidence indicates that tree population responses are influenced by many factors: including lifespans, seed productivity and dispersibility, phenotypic plasticity, genetic variability, competition, and disturbance. Some population characteristics should allow rapid changes in population sizes, while others should confer stability in times of environmental fluctuation. Interactions between controlling factors should result in a wide array of possible responses to climatic change. Interpretations of late-Quaternary forest dynamics must be based on an understanding of the biological processes involved in population responses to environmental variations.