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James E. Whitney Joanna B. Whittier Craig P. Paukert Julian D. Olden Angela L. Strecker 《Reviews in Fish Biology and Fisheries》2017,27(2):463-479
Climate change is poised to alter the distributional limits, center, and size of many species. Traits may influence different aspects of range shifts, with trophic generality facilitating shifts at the leading edge, and greater thermal tolerance limiting contractions at the trailing edge. The generality of relationships between traits and range shifts remains ambiguous however, especially for imperiled fishes residing in xeric riverscapes. Our objectives were to quantify contemporary fish distributions in the Lower Colorado River Basin, forecast climate change by 2085 using two general circulation models, and quantify shifts in the limits, center, and size of fish elevational ranges according to fish traits. We examined relationships among traits and range shift metrics either singly using univariate linear modeling or combined with multivariate redundancy analysis. We found that trophic and dispersal traits were associated with shifts at the leading and trailing edges, respectively, although projected range shifts were largely unexplained by traits. As expected, piscivores and omnivores with broader diets shifted upslope most at the leading edge while more specialized invertivores exhibited minimal changes. Fishes that were more mobile shifted upslope most at the trailing edge, defying predictions. No traits explained changes in range center or size. Finally, current preference explained multivariate range shifts, as fishes with faster current preferences exhibited smaller multivariate changes. Although range shifts were largely unexplained by traits, more specialized invertivorous fishes with lower dispersal propensity or greater current preference may require the greatest conservation efforts because of their limited capacity to shift ranges under climate change. 相似文献
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Patterns and uncertainties of species' range shifts under climate change 总被引:10,自引:0,他引:10
Wilfried Thuiller 《Global Change Biology》2004,10(12):2020-2027
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Sodium and gating current time shifts resulting from changes in initial conditions 总被引:4,自引:6,他引:4
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The sodium and gating currents of the squid giant axon elicited by a depolarizing pulse are delayed, with little change in shape, as a result of a hyperpolarizing prepulse. The delays are almost completely saturated, at approximately 45 microseconds, for prepulses to -140 mV. At 8 degrees C they develop with time constants of between 60 and 180 microseconds for prepulses in the -130- to -150-mV range. There is a correlation between the extra charge moved during the gating current and the increase in the time delay of the sodium current as the magnitude of the hyperpolarizing prepulse is increased. These results strengthen the conclusion that the gating current is indeed closely associated with the process of sodium channel opening and provide information concerning the kinetics of the early steps, which are hidden in ionic current measurements. The main features of the gating and sodium current time shifts and the correlation between charge movement and time shifts are duplicated by a sequential six-state model for sodium activation. 相似文献
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昆虫对降雨和干旱的响应与适应 总被引:1,自引:0,他引:1
水分因子在昆虫的生长发育及其整个生活史中起着至关重要的作用。降雨作为改变环境水分的方式之一,其机械冲刷作用对昆虫具有直接的致死效应,并影响昆虫的生长发育、繁殖及其产卵和取食行为等;干旱作为降雨减少导致的极端环境形式,不仅对昆虫生理产生直接影响,而且还会通过影响寄主植物而间接作用于昆虫;同时,干旱还会改变同一寄主植物上昆虫之间的种间关系,导致群落多样性和稳定性的变化以及种群演替的发生。本文综述了气候变化背景下降雨和干旱对昆虫生长发育和繁殖的影响,并介绍了迁飞型昆虫、群居型昆虫、土壤害虫等对降雨和干旱的行为反应;此外,还详细介绍了昆虫对降雨和干旱的适应对策(包括对水分因子的行为适应对策、滞育和迁飞对策等),并建议利用环境水分(尤其是土壤水分)调控措施(如人工降雨和灌溉等)来防治农业害虫。 相似文献
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Meta Virant-Doberlet Geoffrey Horseman Werner Loher Franz Huber 《Cell and tissue research》1994,277(1):39-50
Retrograde and orthograde labeling of neurons projecting to the corpus allatum was performed in locust, grasshopper, cricket, and cockroach species in order to identify brain neurons that may be involved in the regulation of juvenile hormone production. In the acridid grasshopper Gomphocerus rufus L., and the locusts Locusta migratoria (R.&F.) and Schistocerca gregaria Forskal, the corpora allata are innervated by two morphologically distinguishable types of brain neurons. One group of 9–13 neurons (depending on species) with somata in the pars lateralis extend axons via the nervus corporis cardiaci 2 and nervus corporis allati 1 to the ipsilateral corpus allatum, whereas two cells in each pars lateralis have bilateral projections and innervate both glands. No direct connection between the pars intercerebralis and corpus allatum has been found. In contrast, neurons with paired axons innervating both glands are not present in Periplaneta americana (L.) and Gryllus bimaculatus de Geer. Instead, two cells in each pars lateralis project only to the gland contralateral to their somata. Electrophysiological experiments on acridid grasshoppers have confirmed the existence of a direct conduction pathway between the two glands via the paired axons of four cells that have been identified by neuroanatomy. These cells are not spontaneously active under experimental conditions. Ongoing discharges in the left and right nerves are unrelated, suggesting that the corpora allata receive independent neuronal inputs from the brain. 相似文献
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Tomanek L 《Physiological and biochemical zoology : PBZ》2008,81(6):709-717
Physiological processes that set an organism's thermal limits are in part determining recent shifts in biogeographic distribution ranges due to global climate change. Several characteristics of the heat-shock response (HSR), such as the onset, maximal, and upper limit of heat-shock protein (Hsp) synthesis, contribute to setting the acute upper thermal limits of most organisms. Aquatic animals from stable, moderately variable, or highly variable thermal environments differ in their HSR. Some animals living in extremely stable thermal environments lack the response altogether. In contrast, rocky intertidal animals that experience highly variable thermal conditions start synthesizing Hsps, that is, the onset of synthesis, below the highest temperatures that they experience. Thus, these organisms experience thermal conditions in their environment that are close to the upper thermal limits in which they can defend themselves against cellular thermal insults by employing the HSR. Subtidal animals are characterized by moderately variable thermal environments, and their cells start synthesizing Hsps above the highest temperatures that they experience. The upper thermal limits against which they can defend themselves are thus much higher than the highest body temperatures they currently experience. Furthermore, the ability to acclimate to changing thermal conditions seems greatest among animals from moderately variable environments and limited in animals from stable and highly variable environments. Thus, these findings suggest that organisms with the narrowest (stenothermal) and the widest (highly eurythermal) temperature tolerance ranges live closest to their thermal limits and have a limited ability to acclimate, suggesting that they will be most affected by global climate change. 相似文献
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Modelling species' range shifts in a changing climate: the impacts of biotic interactions, dispersal distance and the rate of climate change 总被引:6,自引:0,他引:6
There is an urgent need for accurate prediction of climate change impacts on species ranges. Current reliance on bioclimatic envelope approaches ignores important biological processes such as interactions and dispersal. Although much debated, it is unclear how such processes might influence range shifting. Using individual-based modelling we show that interspecific interactions and dispersal ability interact with the rate of climate change to determine range-shifting dynamics in a simulated community with two growth forms--mutualists and competitors. Interactions determine spatial arrangements of species prior to the onset of rapid climate change. These lead to space-occupancy effects that limit the rate of expansion of the fast-growing competitors but which can be overcome by increased long-distance dispersal. As the rate of climate change increases, lower levels of long-distance dispersal can drive the mutualists to extinction, demonstrating the potential for subtle process balances, non-linear dynamics and abrupt changes from species coexistence to species loss during climate change. 相似文献
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ABSTRACT: BACKGROUND: Mongolia's riverine landscape is divided into three watersheds, differing in extent of permafrost, amount of precipitation and in hydrological connectivity between sub-drainages. In order to assess the vulnerability of macroinvertebrate communities to ongoing climate change, we consider the taxonomic and functional structures of stream communities in two major watersheds: The Central Asian Internal Watershed (CAIW) and the Arctic Ocean Watershed (AOW), together covering 86.1% of Mongolia's surface area. We assess the consequences of the hydrological connectivity between sub-drainages on the nestedness and distinctness of the stream communities. And accordingly, we discuss the expected biotic changes to occur in each watershed as a consequence of climate change. RESULTS: Gamma and beta diversities were higher in the CAIW than the AOW. High community nestedness was also found in the CAIW along with a higher heterogeneity of macroinvertebrate assemblage structure. Assemblages characteristic of cold headwater streams in the CAIW, were typical of the drainages of the Altai Mountain range. Macroinvertebrate guilds of the CAIW streams exhibited traits reflecting a high stability and low resilience capacity for eutrophication. In contrast, the community of the AOW had lower nestedness and a combination of traits reflecting higher stability and a better resilience capacity to disturbances. CONCLUSION: Higher distinctness of stream communities is due to lower connectivity between the drainages. This was the case of the stream macroinvertebrate communities of the two major Mongolian watersheds, where connectivity of streams between sub-drainages is an important element structuring their communities. Considering differences in the communities' guild structure, hydrological connectivity and different magnitudes of upcoming impacts of climate change between the two watersheds, respective stream communities will be affected differently. The hitherto different communities will witness an increasing differentiation and divergent adaptations for the upcoming changes. Accordingly, in an increasing awareness to protect Mongolia's nature, our results encourage adapting conservation planning and management strategies specifically by watershed. 相似文献
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Quantifying species' range shifts in relation to climate change: a case study of Abies spp. in China
Predicting species range shifts in response to climatic change is a central aspect of global change studies. An ever growing number of species have been modeled using a variety of species distribution models (SDMs). However, quantitative studies of the characteristics of range shifts are rare, predictions of range changes are hard to interpret, analyze and summarize, and comparisons between the various models are difficult to make when the number of species modeled is large. Maxent was used to model the distribution of 12 Abies spp. in China under current and possible future climate conditions. Two fuzzy set defined indices, range increment index (I) and range overlapping index (O), were used to quantify range shifts of the chosen species. Correlation analyses were used to test the relationships between these indices and species distribution characteristics. Our results show that Abies spp. range increments (I) were highly correlated with longitude, latitude, and mean roughness of their current distributions. Species overlapping (O) was moderately, or not, correlated with these parameters. Neither range increments nor overlapping showed any correlation with species prevalence. These fuzzy sets defined indices provide ideal measures of species range shifts because they are stable and threshold-free. They are reliable indices that allow large numbers of species to be described, modeled, and compared on a variety of taxonomic levels. 相似文献
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Uncertainty in projections of global change impacts on biodiversity over the 21st century is high. Improved predictive accuracy is needed, highlighting the importance of using different types of models when predicting species range shifts. However, this is still rarely done. Our approach integrates the outputs of a spatially‐explicit physiologically inspired model of extinction and correlative species distribution models to assess climate‐change induced range shifts of three European reptile species (Lacerta lepida, Iberolacerta monticola, and Hemidactylus turcicus) in the coming decades. We integrated the two types of models by mapping and quantifying agreement and disagreement between their projections. We analyzed the relationships between climate change and projected range shifts. Agreement between model projections varied greatly between species and depended on whether or not they consider dispersal ability. Under our approach, the reliability of predictions is greatest where the predictions of these different types of models converge, and in this way uncertainty is reduced; sites where this convergence occurs are characterized by both current high temperatures and significant future temperature increase, suggesting they may become hotspots of local extinctions. Moreover, this approach can be readily implemented with other types of models. 相似文献
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Kingsolver JG Woods HA Buckley LB Potter KA MacLean HJ Higgins JK 《Integrative and comparative biology》2011,51(5):719-732
Many organisms have complex life cycles with distinct life stages that experience different environmental conditions. How does the complexity of life cycles affect the ecological and evolutionary responses of organisms to climate change? We address this question by exploring several recent case studies and synthetic analyses of insects. First, different life stages may inhabit different microhabitats, and may differ in their thermal sensitivities and other traits that are important for responses to climate. For example, the life stages of Manduca experience different patterns of thermal and hydric variability, and differ in tolerance to high temperatures. Second, life stages may differ in their mechanisms for adaptation to local climatic conditions. For example, in Colias, larvae in different geographic populations and species adapt to local climate via differences in optimal and maximal temperatures for feeding and growth, whereas adults adapt via differences in melanin of the wings and in other morphological traits. Third, we extend a recent analysis of the temperature-dependence of insect population growth to demonstrate how changes in temperature can differently impact juvenile survival and adult reproduction. In both temperate and tropical regions, high rates of adult reproduction in a given environment may not be realized if occasional, high temperatures prevent survival to maturity. This suggests that considering the differing responses of multiple life stages is essential to understand the ecological and evolutionary consequences of climate change. 相似文献
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Pioneering efforts to predict shifts in species distribution under climate change used simple models based on the correlation between contemporary environmental factors and distributions. These models make predictions at coarse spatial scales and assume the constancy of present correlations between environment and distribution. Adaptive management of climate change impacts requires models that can make more robust predictions at finer spatio-temporal scales by accounting for processes that actually affect species distribution on heterogeneous landscapes. Mechanistic models of the distribution of both species and vegetation types have begun to emerge to meet these needs. We review these developments and highlight how recent advances in our understanding of relationships among the niche concept, species diversity and community assembly point the way towards more effective models for the impacts of global change on species distribution and community diversity. 相似文献
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Responses of periphyton to changes in current velocity, suspended sediment and phosphorus concentration 总被引:10,自引:0,他引:10
RICHARD R. HORNER EUGENE B. WELCH MARGUERITE R. SEELEY JEAN M. JACOBY 《Freshwater Biology》1990,24(2):215-232
SUMMARY.
- 1 Research was performed in laboratory streams to evaluate periphytic biomass accrual, export, and community composition over a range of limiting nutrient (phosphorus) concentrations with variable velocity, and suspended sediment addition, in comparison to constant velocity and no suspended sediment. In fixed-velocity treatments, velocity increase to 60 cm s?1 significantly enhanced biomass accrual, but further increase resulted in substantial biomass reduction. Average biomass loss rates did not change significantly over a velocity range of 10–80 cm s?1. Diatoms were favoured at relatively high velocities and low phosphorus concentrations, whereas the blue-green Phormidium tended to dominate at higher SRP concentrations and the green Mougeotia seemed to prefer lower velocities.
- 2 Sudden increases in velocity raised instantaneous loss rates by an order of magnitude or more, but these high rates persisted only briefly. As a result, marked biomass reductions were not apparent a day after the velocity change. Dominance change from filamentous green or blue-green to diatoms immediately after the increase was reversed within 2 days. Loss rate increases due to solids addition were much smaller than those accompanying velocity increase, but simultaneous velocity elevation and solids addition produced instantaneous loss rates approximately double those with velocity increase alone.
- 3 The experiments demonstrated that an elevation in velocity, above that to which algae were accustomed, led to increased loss rates and temporarily reduced biomass. However, recolonization and growth after biomass reduction were apparently rapid. Substantial export of periphyton following solids addition required erosion of the protective boundary layer accompanied by a velocity increase. These results arc applicable to understanding the response of lotic periphytic algae to elevated, turbid storm discharges and similar runoff or high-flow events.
- 4 Areal uptake rates of P by algae growing in the laboratory streams increased with soluble reactive phosphorus (SRP) concentration, up to approximately 15 μg I?1 in overlying water. They also increased above 35 cm s ?1. Overall, uptake rate seemed to vary inversely with biomass. The ralio of areal uptake rate/biomass was significantly less where mean biomass was 411±6 mg chl a m?2 compared to 223±17 mg chl a m?2.
- 5 The results suggested that although nutrient uptake is primarily a surface phenomenon, diffusion to interior cells can also determine the responses of attached communities. Both diffusion and uptake rate were stimulated by increasing nutrient concentration and velocity up to certain levels, but became limited by biofilm thickness and scouring.
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全世界地表平均温度在上个世纪增加了0.74℃,并且在未来还会持续增加。在过去的20年,气候变暖对生物系统的影响吸引了大量的研究。本文综述了由温度升高为主要驱动因子的气候变化对昆虫适合度的影响,主要从昆虫越冬存活率、化性(世代数)、扩散迁移、发生分布、物候关系5个方面阐述气候变暖对昆虫发生发展的作用,认为未来应长期进行昆虫种群动态监测预警,更关注气候变暖下植物-害虫-天敌互作关系的研究。 相似文献
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Due to past and current climatic changes, range contractions and range shifts are essential stages in the history of a species. However, unlike range expansions, the molecular consequences of these processes have been little investigated. In order to fill this gap, we simulated patterns of molecular diversity within and between populations for various types of range contractions and range shifts. We show that range contractions tend to decrease genetic diversity as compared with population with stable ranges but quite counterintuitively fast range contractions preserve higher levels of diversity and induce lower levels of genetic differentiation among refuge areas than slow contractions. Contrastingly, fast range shifts lead to lower levels of diversity than slow range shifts. At odds with our expectations, we find that species actively migrating toward refuge areas can only preserve higher levels of diversity in refugia if the contraction is rapid. Under slow range contraction or slow range shift, active migration toward refugia lead to a larger loss of diversity as compared with scenarios with isotropic migration and may thus not be a good evolutionary strategy. These results suggest that the levels of diversity preserved after a climate change both within and between refuge areas will not only depend on the dispersal abilities of a species but also on the speed of the change. It also implies that a given episode of climatic change will impact differently species with different generation times. 相似文献
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Climate change is now estimated by some biologists to be the main threat to biodiversity, but doubts persist regarding which species are most at risk, and how best to adapt conservation management. Insects are expected to be highly responsive to climate change, because they have short life cycles which are strongly influenced by temperature. Insects also constitute the most diverse taxonomic group, carrying out biotic interactions of importance for ecological functioning and ecosystem services, so their responses to climate change are likely to be of considerable wider ecological significance. However, a review of recent published evidence of observed and modelled effects of climate change in ten high-ranking journals shows that comparatively few such studies have focused on insects. The majority of these studies are on Lepidoptera, because of the existence of detailed contemporary and historical datasets. These biases in published information may influence conclusions regarding the threat of climate change to insect biodiversity. Assessment of the vulnerability of insect species protected by the Bern Convention on the Conservation of European Wildlife and Natural Habitats also emphasises that most information is available for the Lepidoptera. In the absence of the necessary data to carry out detailed assessments of the likely effects of climate change on most threatened insects, we consider how autecological studies may help to illuminate the potential vulnerability of species, and draw preliminary conclusions about the priorities for insect conservation and research in a changing climate. 相似文献