Local Climatic Factors Research Articles

Lake ice phenology of Nam Co, Central Tibetan Plateau, China, derived from multiple MODIS data products

Abstract Lake ice phenology, including freeze-up and break-up dates, is a sensitive indicator of climate change. However, uniformly created lake ice phenology records are still required on the Tibetan Plateau (TP) for a more accurate analysis of climate change. In this study, we present a new automated method to extend the interpretation of existing in-situ lake ice records, using multiple MODIS data products. Our results showed strong agreement with the in-situ data at Nam Co (Co means lake in Tibetan language) on the central TP. The multiple MODIS based method is therefore well-suited to the detection of lake ice phenology. The result showed that in 2000–2015, the mean lake ice duration (ID) in the middle of Nam Co was ~ 87 d; the freeze-up start (FUS) date delayed 0.58 d/yr and the break-up start (BUS) date delayed 0.09 d/yr, giving a total decrease in ID at the rate of 0.49 d/yr. We suggest the delayed freeze-up dates became more marked in response to climate warming. Changes in lake ice coverage in Nam Co are affected by a number of local and regional climatic factors, such as air temperature and wind speed.

Design Factors Contributing to Active Urban Squares in Malaysia

Urban squares are a type of public open space that cater for various activities for the public, such as for events and leisure. The activities in the square are not only contributed by annual events and celebrations, but also daily and weekly informal activities of visitors and tourists. Some squares even become landmarks and focal points of the city. While the design of urban squares has been studied in depth by researchers in other countries, however, local studies that interrogate how urban squares are occupied in Malaysia are still scarce. This research examines three prominent urban squares, which are Dataran Putra, Dataran Merdeka and Dataran Pahlawan, to explore and outline the key criteria that contribute to the activities of the squares. The research objectives are: 1) To identify the spaces, design elements, structures and surrounding area; 2) To map the activities and flow of users throughout the day; and 3) To synthesize the key findings to formulate design strategies for urban squares in Malaysia. The methods adopted for this research comprise of conducting site inventory and photographic documentation, observation and mapping, and semi-structured interviews with 150 visitors. The analysis reveals that there are five (5) key criteria that contribute to an active urban square. The findings from this research are useful for Landscape Architects and Urban Designers in planning and designing urban squares in Malaysia, or upgrading underutilized urban squares. This research concludes that an active and successful urban square can contribute to the city’s livability and quality of life for its people. In order to remain active and successful, urban square designs in Malaysia should meet the needs of the local climatic and socio-cultural factors.

Origin and mechanisms of high salinity in Hombolo Dam and groundwater in Dodoma municipality Tanzania, revealed

The Hombolo dam (HD), in central Tanzania, is a shallow reservoir characterized by high salinity that limits its use for human activities. The origin of the salinity, mechanisms of reaching and concentrating in the dam remain unclear. These were assessed using hydrogeochemical facies, water type evolutions and mapping. The source of HD salinity was identified to be shallow groundwater (SG) and runoff from a seasonal floodplain with NaCl-rich lithological materails, along Little Kinyasungwe River that feeds the dam. The NaCl-rich lithological units, about 5–7 km upstream of the dam, were highly concentrated with NaCl to the extent that the local community was commercially separating table salt from them. The physicochemical parameters from these NaCl-rich lithological materials were well represented in HD and nearby groundwater sources, which suggests active water interactions. Water type evolution and surface hydrology assessments clearly showed that SG in the salty-floodplain was influenced by evaporation (ET) and was periodically carried to the HD. Clearly; HD water had high chemical similarity with the nearby SG. This agrees with previous studies that HD is partly fed by the local aquifer. However, this is the first attempt at mapping its physical origin. The origin of HD salinity was further supported by the spatial distribution of electrical conductivity (EC), where very high EC (up to 21,230 μScm−1) was recorded in SG within the NaCl-rich lithological unit while water sources far away from the NaCl-rich materials had much lower EC values. Thus, the study disagrees with previous conclusions that HD salinity was sorely due to high dam surface ET but is primarily due to geological reasons. Comparisons of HD with a nearby Matumbulu dam (MD), another earthen dam in climatologically similar settings, reveals that MD water was less saline/mineralised. This further shows that HD high salinity is most likely a geologic phenomenon, but local climatic factors, namely high ET, decreasing rainfall and warming trends are likely to have concentrated the salts further. Although HD is widely/ideally used for grape vine irrigation, it was clearly revealed that its prolonged usage would potentially affect the soil and grape productivity due to high salinity.

Pola Arus Permukaan dan Kondisi Fisika Perairan di Sekitar Pulau Selayar pada Musim Peralihan 1 dan Musim Timur

<strong>Surface Current Pattern and Physics Condition of Waters Around Selayar Island in the First Transitional and Southeast Monsoons. </strong> Seasonal observations of the flow of surface water and physics conditions around Selayar Island adjacent to Arlindo throughflow pathways of Makassar Strait have been conducted with a focus on the first transitional season and the southeast monsoon season. The purpose of this research is to obtain the pattern of seasonal surface current and physics characteristics of water column, i.e. temperature and salinity in Selayar Island waters during those seasons. The observations conducted on 22–27 May 2015 and 7–10 August 2015 illustrated the successive periods of the first transitional season and the southeast monsoon season. The methods used for taking oceanographic data such as temperature, salinity, and current were the stationary oceanographic measurement using CTD and currentmeter at 29 stations located in surrounding waters of Selayar Island. The surface current pattern generated from the interpolation process of the overall observation stations indicated that during the first transitional season the current moved eastward with an average velocity of 0.25 m/s. During the southeast monsoon season, the same pattern was still observed with a slightly higher average velocity of 0.26 m/s. The temperatures and salinity of Selayar Island waters during the southeast monsoon season were 2°C lower and 0.5 psu higher than during the first transitional season. Differences in mean current velocity values tended to be more affected by local tidal conditions. Different salinity was thought to be influenced by upwelling phenomena and local climatic factors such as rainfall, wind, and river flow discharge.

El Niño and the shifting geography of cholera in Africa

The El Niño Southern Oscillation (ENSO) and other climate patterns can have profound impacts on the occurrence of infectious diseases ranging from dengue to cholera. In Africa, El Niño conditions are associated with increased rainfall in East Africa and decreased rainfall in southern Africa, West Africa, and parts of the Sahel. Because of the key role of water supplies in cholera transmission, a relationship between El Niño events and cholera incidence is highly plausible, and previous research has shown a link between ENSO patterns and cholera in Bangladesh. However, there is little systematic evidence for this link in Africa. Using high-resolution mapping techniques, we find that the annual geographic distribution of cholera in Africa from 2000 to 2014 changes dramatically, with the burden shifting to continental East Africa-and away from Madagascar and portions of southern, Central, and West Africa-where almost 50,000 additional cases occur during El Niño years. Cholera incidence during El Niño years was higher in regions of East Africa with increased rainfall, but incidence was also higher in some areas with decreased rainfall, suggesting a complex relationship between rainfall and cholera incidence. Here, we show clear evidence for a shift in the distribution of cholera incidence throughout Africa in El Niño years, likely mediated by El Niño's impact on local climatic factors. Knowledge of this relationship between cholera and climate patterns coupled with ENSO forecasting could be used to notify countries in Africa when they are likely to see a major shift in their cholera risk.

Selection of target LEED credits based on project information and climatic factors using data mining techniques

Developed by the United States Green Building Council, Leadership in Energy and Environmental Design (LEED) is a credit-based rating system that provides third-party verification for green buildings. Selection of target credits is important yet challenging for LEED managers because various factors such as target certification grade level and building features need to be considered on a case-by-case basis. Local climatic factors could affect the selection of green building technologies and hence the target credits, but currently there is no research suggesting target LEED credits based on climatic factors. This paper presents a methodology for the selection of target LEED credits based on project information and climatic factors. This study focuses on projects certified with LEED for Existing Buildings (LEED-EB). Information of 912 projects and their surrounding climatic circumstances was collected and studied. 55 classification models for 47 LEED-EB credits were then constructed and optimized using three classification algorithms - Random Forests, AdaBoost Decision Tree, and Support Vector Machine (SVM). The results showed that Random Forests performed the best in most of the 55 classification models. With a combination of the three algorithms, the trained classification models were used to develop a web-based decision support system for LEED credit selection. The system was tested using 20 recently certified LEED projects, and the results showed that our system had an accuracy of 82.56%.

The Potential of Recycled Locally-Sourced Waste Materials for Green Roof Soil Mixtures

The increase in surface runoff has become a serious environmental problem and concern in Malaysia. Hence, promoting the use of green roofs in urban areas will potentially allow some storage area and time attenuation for any rainfall. Initial studies on a few substrate mixtures were done in order to find out the properties of green roof media. These included vermiculite (V), perlite (P) and peat moss (PM) together with locally-sourced waste materials such as empty fruit bunches (EFB) and wet diaper gel (D) which are expected to potentially retain more storm water runoff. A test on the substrate mixture properties and evaporation tests were conducted on seven types of soil mixtures. The results show that a basic substrate mixture of PVPM3,5,2 has a maximum water capacity of 50%. The modification and addition of diaper gel in DVPM1,3,2 and empty fruit bunch (EFB) in PEFBPM1,0.3,2 show an increment in both mixtures’ water holding capacity (54%). All the proposed mixtures have shown permeability values larger than 0.0005 cm/s. To investigate the maximum water storage availability, the evaporation tests show that both mixtures could provide 60 - 62 mm of water storage after 34 days without rainfall under ambient climatic condition (32 ̊ to 34 ̊) whereas under extreme heat temperatures (50 ̊), both mixtures took only 1 day to provide the same storage as the ambient condition. Therefore, this study has provided an initial understanding of the properties of the substrate mixture as well as the evaporation rate of the materials tested. This information can be used to demonstrate the relationship between soil characteristics and local climatic factors (temperature).

Phenological patterns of flowering across biogeographical regions of Europe.

Long-term changes of plant phenological phases determined by complex interactions of environmental factors are in the focus of recent climate impact research. There is a lack of studies on the comparison of biogeographical regions in Europe in terms of plant responses to climate. We examined the flowering phenology of plant species to identify the spatio-temporal patterns in their responses to environmental variables over the period 1970-2010. Data were collected from 12 countries along a 3000-km-long, North-South transect from northern to eastern Central Europe.Biogeographical regions of Europe were covered from Finland to Macedonia. Robust statistical methods were used to determine the most influential factors driving the changes of the beginning of flowering dates. Significant species-specific advancements in plant flowering onsets within the Continental (3 to 8.3 days), Alpine (2 to 3.8 days) and by highest magnitude in the Boreal biogeographical regions (2.2 to 9.6 days per decades) were found, while less pronounced responses were detected in the Pannonian and Mediterranean regions. While most of the other studies only use mean temperature in the models, we show that also the distribution of minimum and maximum temperatures are reasonable to consider as explanatory variable. Not just local (e.g. temperature) but large scale (e.g. North Atlantic Oscillation) climate factors, as well as altitude and latitude play significant role in the timing of flowering across biogeographical regions of Europe. Our analysis gave evidences that species show a delay in the timing of flowering with an increase in latitude (between the geographical coordinates of 40.9 and 67.9), and an advance with changing climate. The woody species (black locust and small-leaved lime) showed stronger advancements in their timing of flowering than the herbaceous species (dandelion, lily of the valley). In later decades (1991-2010), more pronounced phenological change was detected than during the earlier years (1970-1990), which indicates the increased influence of human induced higher spring temperatures in the late twentieth century.

Reconstructing seasonality using d18O in incremental layers of human enamel: a test of the analytical protocol developed for SHRIMP IIe/MC ion microprobe

A number of recent studies dealing with palaeoclimate and environmental reconstruction include the measurement of oxygen isotope composition of mammalian teeth. Some of them analyse a temporal sequence of the changes recorded in bioapatite from enamel layers representing the whole period of tooth development. Enamel samples display large intra-tooth δ 18 O variations that may reflect a seasonal fluctuation in the δ 18 O of local palaeoclimate parameters. The present paper provides an effective analytical protocol for sequential δ 18 O analysis of human teeth using SHRIMP IIe/MC ion microprobe. It is possible to follow the inner enamel layer along enamel-dentine junction on a high spatial scale in a range about 0.02 mm of spot diameter and 0.12–0.14 mm of the distance between spots. Using the methodology described herein, we can achieve an external precision for δ 18 O analysis <0.2‰ (1σ). The number of 60 to 90 single analyses covering the enamel layer between the incisal and apical ends is enough to obtain temporal resolution of less than one month and to document precisely seasonal fluctuation caused by local environmental and climate factors. The methodology of δ 18 O in situ measurements has been tested on human teeth from Tell Majnuna, a 4th millennium BCE cemetery in Northern Mesopotamia, which is a relatively arid area with high seasonal differences in precipitation and temperature. Observed pattern of δ 18 O variations is consistent with expected seasonal fluctuations, although the overall effect is blurred by some inertia in the enamel maturation.

Assessing multi-site δ18O-climate calibrations of the coralline alga Clathromorphum across the high-latitude Northern Hemisphere

An increased number of climate proxy records and more refined interpretation of proxy data are crucial to improve projections of future climate at high latitudes, where internal feedbacks amplify warming and established high-resolution climate archives are especially sparse. Encrusting coralline algae are being developed as a mid- to high-latitude marine climate archive. These long-lived algae form a solid high-Mg calcite skeleton with annual growth bands similar to those of trees and tropical corals. The oxygen isotope ratio of the algal skeleton (δ18Oalg) records local environmental and climatic factors, notably sea surface temperature and seawater δ18O.Here we assess the δ18Oalg–climate relationship in diverse environments across the algal habitat range utilizing two species of coralline algae from the genus Clathromorphum. Clathromorphum is widely distributed from the cold-temperate North Atlantic and Pacific to the Arctic Ocean and has recently yielded numerous climate reconstructions of up to 650years in length. In this study, we calibrate δ18Oalg of four specimens to gridded temperature and salinity data, the latter a proxy for seawater δ18O. These specimens were collected from a variety of algal growth environments across the high-latitude Northern Hemisphere: two specimens from the Aleutian Archipelago, one from the Canadian Arctic, and one from the Gulf of Maine. Low winter temperatures and insolation restrict the months when algae record local climate in the δ18O of their skeletons; we therefore determine these response seasons by correlating monthly temperature and salinity anomalies with annual δ18Oalg anomalies at each site. We then average gridded data over months that correlate significantly (95% confidence interval) for regression with δ18Oalg. While the timing and nature of the climate signal vary across sites, we find significant relationships between δ18Oalg and either temperature or salinity averaged over the response season at three sites. Variation in local climatology among the four sites provides a physical explanation for calibration differences, compounded by uncertainties stemming from the proxy chronology, biological variability, temporal coverage, and sparse historical climate data. This work takes an essential step toward reconstructing high-latitude marine climate patterns with coralline algal δ18O and developing algae proxy system models.

Association between Meteorological Factors and Aseptic Meningitis in Six Metropolitan Provinces of the Republic of Korea

Background: Enteroviral aseptic meningitis has become an important public health burden in Asian countries among children. Although the seasonal variations of aseptic meningitis have been recognized in several regions, the exact mechanisms responsible for this phenomenon have not yet been systematically examined. This study analyzed the association between meteorological variables and aseptic meningitis cases in six metro provinces of the Republic of Korea. Methods: Aseptic meningitis patients in between January 2002 to December 2012 were extracted from the National Health Insurance payment request data of the Republic of Korea. Incidences were calculated. Time series distribution with local and oceanic climate factors was plotted. Weekly lag effects of climate factors on number of aseptic meningitis cases were observed. We estimated the province specific generalized additive model and province combined generalized additive mixed model with quasipoisson regression. The associations during non-epidemic years were compared with epidemic years. Results: The overall incidence of aseptic meningitis was 6.5 per 10,000. The highest numbers of cases were found in summer months. Mean temperature in the same week and Niño-3 at 11-week lag were positively associated with aseptic meningitis cases. Mean temperature at 0-week lag in non-epidemic years and solar radiation at 5-week lag in epidemic years showed the positive effect on the development of aseptic meningitis. Niño-3 at 11-week lag during epidemic years of aseptic meningitis had the highest significant positive association with nearly S-shaped distribution. Conclusions: This study suggests that both local weather variables and oceanic climate factors play important role in the development of aseptic meningitis in six Korean metro provinces. Appropriate disease preventive measures and public health actions are required to reduce the risk of global climate change with the consideration of local weather conditions.

Single-Locus versus Multilocus Patterns of Local Adaptation to Climate in Eastern White Pine (Pinus strobus, Pinaceae).

Natural plant populations are often adapted to their local climate and environmental conditions, and populations of forest trees offer some of the best examples of this pattern. However, little empirical work has focused on the relative contribution of single-locus versus multilocus effects to the genetic architecture of local adaptation in plants/forest trees. Here, we employ eastern white pine (Pinus strobus) to test the hypothesis that it is the inter-genic effects that primarily drive climate-induced local adaptation. The genetic structure of 29 range-wide natural populations of eastern white pine was determined in relation to local climatic factors using both a reference set of SSR markers, and SNPs located in candidate genes putatively involved in adaptive response to climate. Comparisons were made between marker sets using standard single-locus outlier analysis, single-locus and multilocus environment association analyses and a novel implementation of Population Graphs. Magnitudes of population structure were similar between the two marker sets. Outlier loci consistent with diversifying selection were rare for both SNPs and SSRs. However, genetic distances based on the multilocus among population covariances (cGD) were significantly more correlated to climate, even after correcting for spatial effects, for SNPs as compared to SSRs. Coalescent simulations confirmed that the differences in mutation rates between SSRs and SNPs did not affect the topologies of the Population Graphs, and hence values of cGD and their correlations with associated climate variables. We conclude that the multilocus covariances among populations primarily reflect adaptation to local climate and environment in eastern white pine. This result highlights the complexity of the genetic architecture of adaptive traits, as well as the need to consider multilocus effects in studies of local adaptation.

Response of radial growth of Pinus koraiensis in broad-leaved Korean pine forests with different latitudes to climatical factors.

To reveal the radial growth trends of Pinus koraiensis and the differences in their responses to climate factors among different latitudes, and to assess the dynamic characteristics, adaptabi-lity and sensitivity of P. koraiensis under the influence of climate change, dendrochronological techniques were used to study the relationships between the climatic variables and the radial growth of P. koraiensis in broad-leaved Korean pine forests with different latitudes. The results showed that there were differences in the responses of the radial growth of P. koraiensis in four different latitudes to local climatic factors. In Baishilazi Nature Reserve, the southernmost sample plot, the radial growth of P. koraiensis was significantly positively correlated to the average relative humidity but significantly negatively correlated to the average maximum temperature of growing season. In low altitude of Changbai Mountain Nature Reserve, the intermediate sample plot, it was significantly positively correlated with precipitation, average relative humidity and PDSI, and significantly negatively correlated with the average maximum temperature in growing season. In Liangshui Nature Reserve, the intermediate sample plot, significantly positive correlations occurred for average relative humidity and PDSI in growing season, while significantly negative correlations occurred for the average temperature and the average maximum temperature in growing season. Nevertheless, in Shengshan Nature Reserve, the northernmost sample plot, it was positively correlated to the tempe-rature factors of most months. The climatic variables in June of current year were the main factors limiting the radial growth of P. koraiensis in all latitudes, and the average maximum temperature in June of current year was highly negatively correlated with radial growth for P. koraiensis measured at all sites. In recent four decades, with the rising of temperature, the radial growth of P. koraiensis decreased significantly in the southernmost point, increased significantly in the northernmost point, and did not change significantly in middle latitudes. The distribution area of P. koraiensis would be reduced if the temperature increased and precipitation remained unchanged in the future.

Advance to the research of the climate factor effect on the distribution of plague

Plague is an anthropozoonotic disease caused by the Yersinia pestis ,which developed by many factors including local climate factors. In recent years, more and more studies on the effects of climate on plague were conducted. According to the researches, climate factors (mainly the rainfall and temperature) affected the development and distribution of plague by influencing the abundance of plague host animals and fleas index. The climate also affected the epidemic dynamics and the scope of plague. There were significant differences existing in the influence of climate on the palgue developed in the north and south China. In the two different plague epidemic systems, the solitary Daurian ground squirrel-flea-plague and the social Mongolian gerbil-flea-plague, the obvious population differences existed among the responses of the host animal to the climate changes. Although the internal relationship between the rainfall, the flea index, the density of rodents and the plague supported the nutritional cascade hypothesis, it can not prove that there is a clear causality between the occurrence of plague and rainfall. So the influence of climate factors on plague distribution can only be used for early forecasting and warning of the plague.

Ecogeographical variation of 12 morphological traits withinPinus tabulaeformis: the effects of environmental factors and demographic histories

Aims More data are needed about how genetic variation (GV) and environmental factors influence phenotypic variation within the natural populations of long-lived species with broad geographic distributions. To fill this gap, we examined the correlations among environmental factors and phenotypic variation within and among 13 natural populations of Pinus tabulaeformis consisting of four demographically distinct groups within the entire distributional range. Methods Using the Akaike's Information Criterion (AIC) model, we measured 12 morphological traits and constructed alternative candidate models for the relationships between each morphological trait and key climatic variables and genetic groups. We then compared the AIC weight for each candidate model to identify the best approximating model for ecogeographical variation of P. tabulaeformis. The partitioning of variance was assessed subsequently by evaluating the independent variables of the selected best models using partial redundancy analysis. Important Findings Significant phenotypic variation of the morphological traits was observed both within individual populations and among populations. Variation partition analyses showed that most of the phenotypic variation was co-determined by both GV and climatic factors. GV accounted for the largest proportion of reproductive trait variation, whereas local key climatic factors (i.e. actual evapotranspiration, AET) accounted for the largest proportion of phenotypic variation in the remaining investigated traits. Our results indicate that both genetic divergence and key environmental factors affect the phenotypic variation observed among populations of this species, and that reproductive and vegetative traits adaptively respond differently with respect to local environmental conditions. This partitioning of factors can inform those making predictions about phenotypic variation in response to future changes in climatic conditions (particularly those affecting AET).

Application of Qual2e Model for River Water Quality Modelling

QUAL2E is modeling software which simulates up to 15 water quality parameters in branching stream system. The model uses mathematical equations like finite-difference solution of the adjective- dispersive mass transport and reaction equations. The program computes a series of steady- state water surface profiles and simulates changes in flow conditions along the stream. The model is applicable only to dendritic streams that are well mixed and it assumes that the major transport mechanism, advection and dispersion are significant only along the main direction of flow of the stream. QUAL2E can operate as either a steady state or a dynamic model and it simulates dynamic dial heat budget and water quality kinetics for a one dimensional and steady flow system. QUAL2E program performs dissolved oxygen balance by including source and sink terms in mass balance equation and is used to quantify the non point sources loading rate, determine the pollutants, calculate the phosphorus and estimate the natural conditions. It accommodates four types of hydraulic and mass load functions in addition to local climate factors: headwater-inputs, point sources, inflow/outflow and downstream boundary conditions.

Evaluation of error in TRMM 3B42V7 precipitation estimates over the Himalayan region

AbstractAccurate precipitation measurement is crucial for weather forecasting and hydrological modeling. Tropical Rainfall Measuring Mission (TRMM) 3B42V7 satellite precipitation product offers an opportunity to monitor precipitation at high spatiotemporal resolution. However, it has several inherent errors related to observation, instrument, and rainfall retrieval algorithms. It is, therefore, essential to validate it with ground‐based measurements. We divide the region into different elevation ranges and compare 3B42V7 with India Meteorological Department gauge‐based measurements, so as to observe the behavior of satellite at different altitudes. This paper evaluates error characteristics of 3B42V7 using continuous and categorical validation schemes. The analysis reveals 3100 m altitude as the breakpoint for the satellite overestimating and underestimating rainfall amount for elevation ranges below and above it, respectively. It gives a poor positive correlation of ~0.23 between individual rainfall events, though the correlation improves (~0.67) for areal‐averaged precipitation values. 3B42V7 also underestimates the frequency of actual rainfall events and is not very good at identifying correct rain and no‐rain events with the overall accuracy of ~66%. Conclusively, the satellite exhibits comparatively better performance for 1000–2000 m elevations but exacerbates over higher‐altitude regions. Further, we assess its capability for very heavy rainfall events using three percentile thresholds. The low‐magnitude bias for 98th and 99th percentiles and high‐magnitude bias for 99.99th percentile imply that 3B42V7 may not be suitable for the study of very heavy rainfall events. On the basis of these findings, it is recommended to improve satellite precipitation retrieval algorithms by incorporating topographical and local climatic factors into consideration.

A series of abnormal climatic conditions caused the most severe outbreak of first-generation adults of the meadow moth (Loxostege sticticalis L.) in China

The meadow moth, Loxostege sticticalis L., is a destructive migratory pest in the northern temperate zone. The outbreak mechanism of first-generation adults in China remains unclear. In 2008, the density of first-generation larvae was very low or even negligible in most sites in China. However, a great number of first-generation adults appeared unexpectedly in late July, and their offspring caused the most severe infestation on record. The present study aims to determine where the large influx of immigrant adults originated from and how this unprecedented population was established. Source areas were explored by trajectory analysis, and climatic patterns related to the population increase were investigated. Results showed that the outbreak population mainly immigrated from Northeast Mongolia and the Chita State of Russia, and the buildup of such a large population could be attributed to an exceptional northward migration of overwintered adults from North China to East Mongolia in the spring of 2007 and unusually favourable climatic conditions in the next two growth seasons. These results indicated that the population dynamics of meadow moth in Northeast Asia would be difficult to predict when only considering local climatic factors and population size within one country. International joint monitoring and information sharing related to this pest between China, Mongolia and Russia should be implemented.

Very high‐resolution digital elevation models: are multi‐scale derived variables ecologically relevant?

Summary Digital elevation models (DEMs) are often used in landscape ecology to retrieve elevation or first derivative terrain attributes such as slope or aspect in the context of species distribution modelling. However, DEM‐derived variables are scale‐dependent and, given the increasing availability of very high‐resolution (VHR) DEMs, their ecological relevance must be assessed for different spatial resolutions. In a study area located in the Swiss Western Alps, we computed VHR DEMs‐derived variables related to morphometry, hydrology and solar radiation. Based on an original spatial resolution of 0·5 m, we generated DEM‐derived variables at 1, 2 and 4 m spatial resolutions, applying a Gaussian Pyramid. Their associations with local climatic factors, measured by sensors (direct and ambient air temperature, air humidity and soil moisture) as well as ecological indicators derived from species composition, were assessed with multivariate generalized linear models (GLM) and mixed models (GLMM). Specific VHR DEM‐derived variables showed significant associations with climatic factors. In addition to slope, aspect and curvature, the underused wetness and ruggedness indices modelled measured ambient humidity and soil moisture, respectively. Remarkably, spatial resolution of VHR DEM‐derived variables had a significant influence on models’ strength, with coefficients of determination decreasing with coarser resolutions or showing a local optimum with a 2 m resolution, depending on the variable considered. These results support the relevance of using multi‐scale DEM variables to provide surrogates for important climatic variables such as humidity, moisture and temperature, offering suitable alternatives to direct measurements for evolutionary ecology studies at a local scale.

Planning for Production of Freshwater Fish Fry in a Variable Climate in Northern Thailand

Provision of adequate numbers of quality fish fry is often a key constraint on aquaculture development. The management of climate-related risks in hatchery and nursery management operations has not received much attention, but is likely to be a key element of successful adaptation to climate change in the aquaculture sector. This study explored the sensitivities and vulnerability of freshwater fish fry production in 15 government hatcheries across Northern Thailand to climate variability and evaluated the robustness of the proposed adaptation measures. This study found that hatcheries have to consider several factors when planning production, including: taking into account farmer demand; production capacity of the hatchery; availability of water resources; local climate and other area factors; and, individual species requirements. Nile tilapia is the most commonly cultured species of freshwater fish. Most fry production is done in the wet season, as cold spells and drought conditions disrupt hatchery production and reduce fish farm demand in the dry season. In the wet season, some hatcheries are impacted by floods. Using a set of scenarios to capture major uncertainties and variability in climate, this study suggests a couple of strategies that should help make hatchery operations more climate change resilient, in particular: improving hatchery operations and management to deal better with risks under current climate variability; improving monitoring and information systems so that emerging climate-related risks are known sooner and understood better; and, research and development on alternative species, breeding programs, improving water management and other features of hatchery operations.