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Many price indices are constructed using bilateral transaction prices. This paper shows how the time series behavior of cross‐sectional price moments can reveal useful information about pricing behavior in bilateral transactions markets. Inference is formalized in a microlevel price determination model that allows for rigid pricing at the level of individual buyer/seller transactions as well as asymmetries in bargaining power. The model is used to estimate pricing rigidities in Norwegian salmon export transactions. Results suggest a high rate of price revisions and an informative salmon price index. The moments suggest price revisions are conducted at fixed time intervals consistent with optimal price revisions under costly information and that price revisions are more likely when transaction prices are below the reference price in the market. [ABSTRACT FROM AUTHOR]

Precision and safety of life applications of Global Navigation Satellite Systems require key information on space weather conditions in particular on the perturbation degree of the ionosphere. Such systems are particularly vulnerable against severe spatial gradients and rapid changes of the total electron content (TEC) measured along different satellite‐receiver links. To estimate spatial gradients and rapid temporal variations of ionospheric TEC, two approaches are discussed. The Gradient Ionosphere indeX (GIX) and the Sudden Ionospheric Disturbance indeX are able to estimate the perturbation degree of the ionosphere instantaneously without taking into account previous measurements. The capabilities and accuracy of the index approaches are demonstrated by simulations using a 3‐D electron density model of the ionosphere and plasmasphere in conjunction with realistic Global Navigation Satellite Signal constellations. Real data tests confirm the applicability of GIX and the related standard deviation GIX Sigma to monitor spatial gradients. Sudden Ionospheric Disturbance indeX is able to monitor rapid temporal variations of TEC as exemplified by using Global Navigation Satellite Signal measurements carried out during solar flare events. Both approaches could identify enhanced space weather impacts on precise point positioning and the European Geostationary Navigation Overlay Service. More comprehensive studies analyzing ionospheric storms in close dialogue with potential customers are needed to fully utilize the potential of these approaches to serve as objective ionospheric indices for scaling horizontal TEC gradients and rapid TEC variations in space weather services. Plain Language Summary: Modern telecommunication and navigation systems may be heavily disturbed by charged particles of the Earth's ionosphere like electrons and ions. These important technological systems may fail due to degradation or even loss of signals during severe perturbations of the ionospheric plasma initiated by severe space weather events. In this paper two methods are described which provide instantaneous information on the perturbation degree of the ionosphere after analyzing continuously transmitted signals from Global Navigation Satellite Signals (GNSS). The data are available via numerous national and international GNSS receiver networks and serve to derive the Total Electron Content of the ionosphere. Using this quantity, spatial gradients and rapid temporal variations of ionospheric Total Electron Content can be estimated in two different approaches over a predefined region. The Gradient Ionosphere indeX and the Sudden Ionospheric Disturbance indeX are able to characterize the spatial and temporal perturbation degree of the ionosphere instantaneously without taking into account previous measurements. The applicability of these indices has been simulated and tested by using GNSS data obtained over Europe. The proposed indices which could easily be distributed via space weather services should be well suited to reducing safety and accuracy risks in GNSS navigation and positioning. Key Points: The new method enables characterizing spatial gradients of the total electron content derived from GNSS dataThe new method enables characterizing rapid ionospheric changes of the total electron content derived from GNSS dataDerived quantities are able to characterize the instantaneous perturbation degree of the ionosphere by indices usable in space weather services [ABSTRACT FROM AUTHOR]

Presented in this paper is a study on the reliability of the electric power supply in Nigeria over the period that immediately preceded the nation's shift from a monopolistic to an unbundled power sector. The study provides a baseline for comparison in the assessment of the post‐deregulation performance of Nigerian electric utilities. Ten years of power outage information (from 1998 to 2007) from the seven major distribution systems of the national grid in use at the time are used to compute the systems' reliability indices using a statistical approach. A sensitivity evaluation is performed to assess how the operational parameters could influence the numerical results. The analysis indicates that the Waterworks Feeder of the Ilorin Distribution System has the lowest System Average Interruption Duration Index (SAIDI) sensitivity of 0.0019, whereas the Etete Feeder of the Benin Distribution System has the highest SAIDI sensitivity of 0.5478 due to prolonged customer interruptions on the feeder. The lowest System Average Interruption Frequency Index (SAIFI) sensitivity of 0.0268 was obtained for the Waterworks Feeder of the Ilorin Distribution System, whereas the 1.0459 SAIFI sensitivity obtained for the Cocoa Feeder of the Ibadan Distribution System was the highest due to frequent interruptions on the feeder. The Waterworks Feeder of the Ilorin Distribution System recorded the lowest Customer Average Interruption Duration Index (CAIDI) sensitivity of 0.0075, whereas a CAIDI sensitivity of 2.8466, which was the highest, was obtained on the Ikpoba Dam Feeder of the Benin Distribution System. The outcome of this study would provide an informational basis for the reevaluation of the country's distribution systems as the nation approaches a decade of deregulation of its power market. This reevaluation could foster additional strategic planning and improved energy management by the distribution companies and other players currently operating across the national grid. [ABSTRACT FROM AUTHOR]

An index measuring interaction importance ( Iimp) was proposed in a paper published on 2010 by the Journal of Ecology. This index, now widely used by researchers, has been claimed to symmetrically range in the interval (−1, 1), with negative values for competition and positive values for facilitation., Here, the index properties are carefully analysed, and it is demonstrated that Iimp can never exceed the value of 0.5 in facilitation., Several years have passed since its publication, yet nobody has corrected the inexact index range, and several researchers continue to inaccurately refer to it. Overlooking this lack of symmetry could potentially lead to biased conclusions., Synthesis. Iimp cannot be treated as a symmetric index for negative and positive interactions. This is only the last of several concerns discussed in literature: current approaches to measuring interaction importance still need to be debated and analysed in depth. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper presents a statistical analysis of heavy rain events recorded by the high resolution network of ARPA Piemonte (Piedmont Region Environmental Protection Agency) rain gauges between 2007 and 2014. In order to define convective heavy rain events over the region, a rainfall threshold of 10 mm in 20 min was chosen. Events were sampled at intervals of 6 h for the warning areas of the Piedmont Region, Italy, and their distribution was studied in relation to the values of instability indices obtained from the European Centre for Medium Range Weather Forecasts Integrated Forecasting System and the COnsortium for Small-scale MOdeling ( COSMO)-I7 operational analyses. The performances of the indices of the two meteorological models were investigated for the different warning areas in a pseudo-operational weather forecasting context, obtaining useful information in the phase of issuing thunderstorm early warnings. The second part of the work had the goal of improving the performance of these indices, modifying the one that showed better verification results in terms of receiver operating characteristic ( ROC) area increase and the K Index ( KI). This was done by introducing dependences on the thickness of geopotential height and wind direction at different levels. KI modifications that displayed better results were called reduced K Index ( KR), obtained by dividing KI by the thickness of geopotential height between 500 and 850 hPa, and KW, obtained by adjusting the KR value with additive constants depending on the wind direction at different levels. KW in particular led to a net improvement of the performance of the original KI over the region. [ABSTRACT FROM AUTHOR]

Europe has been affected by record‐breaking heat waves in recent decades. Using station data and a gridded reanalysis as input, four commonly used heat wave indices, the heat wave magnitude index daily (HWMId), excess heat factor (EHF), wet‐bulb globe temperature (WBGT) and universal thermal climate index (UTCI), are computed. The extremeness of historical European heat waves between 1979 and 2019 using the four indices and different metrics is ranked. A normalisation to enable the comparison between the four indices is introduced. Additionally, a method to quantify the influence of the input parameters on heat wave magnitude is introduced. The spatio‐temporal behaviour of heat waves is assessed by spatial–temporal tracking. The areal extent, large‐scale intensity and duration are visualized using bubble plots. As expected, temperature explains the largest variance in all indices, but humidity is nearly as important in WBGT and wind speed plays a substantial role in UTCI. While the 2010 Russian heat wave is by far the most extreme event in duration and intensity in all normalized indices, the 2018 heat wave was comparable in size for EHF, WBGT and UTCI. Interestingly, the well‐known 2003 central European heat wave was only the fifth and tenth strongest in cumulative intensity in WBGT and UTCI, respectively. The June and July 2019 heat waves were very intense, but short‐lived, thus not belonging to the top heat waves in Europe when duration and areal extent are taken into account. Overall, the proposed normalized indices and the multi‐metric assessment of large‐scale heat waves allow for a more robust description of their extremeness and will be helpful to assess heat waves worldwide and in climate projections. [ABSTRACT FROM AUTHOR]

The sediment connectivity concept is particularly suitable for tackling complex, multidisciplinary questions through systems thinking. However, it is unclear how to directly measure connectivity, and so proxy variables are often applied by indices to provide estimates. In this study, we critically evaluate a broad range of connectivity indices encompassing structural and functional connectivity as well as hillslope channel coupling. We then discuss their role in providing a more holistic estimation of connectivity within the Tahoma Creek Watershed, WA. Of the 14 km of channel below the glacier front, the upper 6 km (0–6 km) are coupled to the adjacent hillslopes. Coupled reaches correspond to regions with a high proportion of area contributing sediment and relatively high connectivity values, where all measures decrease in the downstream direction. A significant transition occurs near river kilometer 6. Here the valley bottom abruptly widens, deposition occurs, and the hillslopes become decoupled from the active channel. This transitional reach is also identified as a geomorphic hotspot based on the network structure. The lower 8 km of channel downstream of this reach are largely depositional and percent contributing area and connectivity values remain low, eventually reaching a minimum. Despite their limitations, we found each method to provide unique and useful information regarding connectivity. The effect of scale and event magnitude on connectivity is illustrated. We also found vegetation, topographic characteristics, and network structure to be important in high‐gradient glacio‐volcanic landscapes. The choice of an index will depend on the research objectives, data availability, and the proxy variables that best describe the variability within the defined area. [ABSTRACT FROM AUTHOR]

Copyright of Regional Science Policy & Practice is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Regional climate projections are developed four Central America and the Caribbean, based on a multiparameter ensemble formed by four configurations with different convective cumulus schemes with the regional model RegCM4 at 25 km grid spacing, driven by the HadGEM2‐ES global model under the RCP4.5 and RCP8.5 scenarios. The precipitation change projections indicate drier conditions compared to present in the near future (2020–2049) and far future (2070–2099) time slices. These drier conditions are statistically significant at the 90% confidence level over the eastern Caribbean, central Atlantic Ocean, and the western Pacific Ocean and are more pronounced in the far future time slice. For temperature, the warmer conditions are statistically significant at the 95% confidence level over the study region. The drier and warmer signals are greater in extension and magnitude in the RCP8.5 than for RCP4.5. Projected changes in precipitation and temperature extreme indices show a reduction of consecutive wet days and an increment of consecutive dry days, with a reduction of cold days and nights and an increase of warm days and nights. Lower precipitation along with increased intensity of extreme events are projected over the Greatest Antilles region. [ABSTRACT FROM AUTHOR]

Aim: Evaluating conservation effectiveness is essential to protect at‐risk species and to maximize the limited resources available to land managers. Over 60% of North American grassland and aridlands have been lost since the 1800s. Birds in these habitats are among the most imperilled in North America, yet most remaining habitats are unprotected. Despite the need to measure impact, conservation efforts on private and working lands are rarely evaluated, due in part to limited availability of suitable methods. Location: Northern Great Plains of North America. Methods: We developed a novel metric to evaluate grassland and aridland bird community response to habitat management, the Bird‐Friendliness Index (BFI), consisting of density estimates of grassland and aridland birds weighted by conservation need and a functional diversity metric to incorporate resiliency. We used the BFI to identify ecologically significant areas for grassland and aridland birds and compared them with other prioritizations. Then, we used the BFI to evaluate the effects of simulated habitat management on grassland and aridland bird communities. Results: The most resilient bird communities were found in the Prairie Potholes region of Alberta, Saskatchewan and North Dakota and the lowest BFI values in the southern and western regions of the Northern Great Plains. BFI values were significantly greater in areas included in one or more prioritization, and increased with the number of prioritizations an area was included within. BFI values increased in response to simulated bird‐friendly habitat management. Main conclusions: Our findings suggest that practices recommended for use in bird‐friendly grassland habitat management plans will increase the abundance and resilience of the grassland and aridland bird community and that bird community responses to management will be detected using the BFI. The BFI is a tool by which conservationists and managers can carry out adaptive management and accountable conservation now and into the future. [ABSTRACT FROM AUTHOR]

Understanding soundscapes, that is, the totality of sounds within a location, helps to assess nature in a more holistic way, providing a novel approach to investigating ecosystems. To date, very few studies have investigated freshwater soundscapes in their entirety and none across a broad spatial scale.In this study, we recorded 12 freshwater streams in South East Queensland continuously for three days and calculated three acoustic indices for each minute in each stream. We then used principal component analysis of summary statistics for all three acoustic indices to investigate acoustic properties of each stream and spatial variation in their soundscapes.All streams had a unique soundscape with most exhibiting diurnal variation in acoustic patterns. Across these sites, we identified five distinct groups with similar acoustic characteristics. We found that we could use summary statistics of AIs to describe daytimes across streams as well. Most difference in stream soundscapes was observed during the daytime with significant variation in soundscapes both between hours and among sites.Synthesis and Application. We demonstrate how to characterize stream soundscapes by using simple summary statistics of complex acoustic indices. This technique allows simple and rapid investigation of streams with similar acoustic properties and the capacity to characterize them in a holistic and universal way. While we developed this technique for freshwater streams, it is also applicable to terrestrial and marine soundscapes. [ABSTRACT FROM AUTHOR]

Much of our current risk assessment, especially for extreme events and natural disasters, comes from the assumption that the likelihood of future extreme events can be predicted based on the past. However, as global temperatures rise, established climate ranges may no longer be applicable, as historic records for extremes such as heat waves and floods may no longer accurately predict the changing future climate. To assess extremes (present‐day and future) over the contiguous United States, we used NOAA's Climate Extremes Index (CEI), which evaluates extremes in maximum and minimum temperature, extreme one‐day precipitation, days without precipitation, and the Palmer Drought Severity Index (PDSI). The CEI is a spatially sensitive index that uses percentile‐based thresholds rather than absolute values to determine climate "extremeness" and is thus well‐suited to compare extreme climate across regions. We used regional climate model data from the North American Regional Climate Change Assessment Program (NARCCAP) to compare a late 20th century reference period to a mid‐21st century "business as usual" (SRES A2) greenhouse gas‐forcing scenario. Results show a universal increase in extreme hot temperatures across all models, with annual average maximum and minimum temperatures exceeding 90th percentile thresholds consistently across the continental United States. Results for precipitation indicators have greater spatial variability from model to model, but indicate an overall movement towards less frequent but more extreme precipitation days in the future. Due to this difference in response between temperature and precipitation, the mid‐21st century CEI is primarily an index of temperature extremes, with 90th percentile temperatures contributing disproportionately to the overall increase in climate extremeness. We also examine the efficacy of the PDSI in this context in comparison to other drought indices. [ABSTRACT FROM AUTHOR]

Copyright of Policy Studies Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Time series of groundwater head measurements serve as a primary source of information on groundwater systems. In different groundwater systems, and across several scales, we observe a multitude of patterns in groundwater time series, resulting from complex hydrogeological setups. Unlike in surface hydrology, there is no generalized classification to categorize and quantify the dynamics in groundwater time series. This leads to a lack of tools that could help us disentangle the information contained in groundwater time series in a systematic way. To approach such a classification, we present a principle for organization to qualitatively describe and to quantify groundwater dynamics in a nonredundant and data efficient way. We devise a descriptive typology of groundwater dynamics and assign quantitative measures, mathematically expressing these dynamics. Based on an extensive data set of daily groundwater hydrographs from central Europe, we analyze the relationship between indices and typology based on principal component analysis. The principal component analysis is also used to investigate and discuss redundancy, that is, indices expressing similar information content of hydrographs. Further, the indices' sensitivity to measurement interval and length of the overall observed period is investigated. Finally, a case study demonstrates the potential of the typology and index approach to link groundwater dynamics to the underlying hydrogeological process controls. The tools provided for characterization and quantification of groundwater dynamics should improve future efforts of groundwater classification and prediction in ungauged aquifers and other applications. Key Points: Features of groundwater level time series are organized conceptuallyQuantitative indices are assigned to the conceptual organization to characterize patterns in time seriesIndex sensitivity analysis and demonstration of the potential for groundwater classification [ABSTRACT FROM AUTHOR]

Abstract: The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. [ABSTRACT FROM AUTHOR]

ABSTRACT: Observational analyses of changing climate extremes over the West Africa region have been limited by the availability of long and high‐quality datasets. To help address this gap, a climate extremes indices workshop was held in the Gambia in December 2011 with participants from 14 West African countries. The resulting analysis utilized 15 annual indices derived from observed daily temperatures and 10 annual indices derived from observed daily precipitation. The analysis was conducted for 166 meteorological stations in 13 countries for 2 periods: 1960–2010 and 1981–2010. The analyses of trends in the annual mean temperature indices have identified statistically significant increases of 0.16 °C/decade and 0.28 °C/decade for mean annual maximum and mean annual minimum temperatures, respectively, averaged over all available land stations in the region during the last 50 years. The seasonal‐temperature‐related indices show significant patterns of warming in all seasons. The annual mean of daily minimum temperature has increased more than the annual mean of daily maximum temperature leading to a decreasing trend in the diurnal temperature range. Warm days and warm nights have become more frequent, and cold days and cold nights have become less frequent. The analyses of precipitation‐based indices indicate spatially non‐coherent changes throughout the study area with few statistically significant trends over the longer period. Exceptions to this are the simple daily intensity index and maximum 5‐day precipitation, which show significant increasing regional trends over both the shorter and longer periods. Additionally, over the recent period (1981–2010) most of the precipitation related indices show significant trends towards wetter conditions. However, this period of increased rainfall follows a decade of significantly drier conditions in the region – it is not clear whether the recent upward trends reflect the ‘recovery’ from this long drought period or represents a long‐term response to warming. [ABSTRACT FROM AUTHOR]

ABSTRACT Severe and organized thunderstorms are historically responsible for high-impact hydrometeorological events in the western Mediterranean area ( Spain, France and Italy). This study presents a meteorological indices-based forecasting tool developed by the Meteo- Hydrological Functional Center of Civil Protection of Liguria Region for the prediction of these phenomena. The tool, in the form of a checklist, takes into account all the physical processes and thermodynamic ingredients driving the formation and the spatio-temporal evolution of thunderstorms and their level of organization. The study was carried out on a series of events occurring in 2009-2014 to assess the checklist performance and identify the most relevant parameters and variables from a predictive ability standpoint. Some indices were found to be useful for general thunderstorm recognition but not necessarily for thunderstorms impacting most from a socio-economic standpoint, namely strong and organized ones; other parameters exhibited a higher degree of reliability for the identification of severe and organized phenomena in Liguria. Furthermore, the analysis was useful for the identification of a seasonal dependence for many variables, for the recalibration of some thresholds in a new version of the checklist and for the identification of local patterns of low level winds favourable to the development and maintenance of well organized and stationary convective systems. The assessment of the new checklist for all the events in 2009-2014 showed a significant enhancement of the performance and helped to identify and sort out the role of each parameter better. [ABSTRACT FROM AUTHOR]

Copyright of Irrigation & Drainage is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim Two frameworks (BASVIL and PODCAR), based on two different functional representations (ordination and dendrogram), have been proposed for partitioning overall functional beta diversity into two analogous components: turnover and nestedness-resultant dissimilarity, or replacement and difference of functional richness, respectively. We compared the two frameworks by testing the influence of functional representations and partitioning methods on the measurement of overall functional beta diversity and its components. Innovation We computed beta-diversity indices from the two frameworks on a set of communities simulated according to five scenarios of assembly: random, richness gradient, pure nestedness, pure turnover and mixed turnover/loss scenarios. To disentangle the effects of the partitioning approach and those of the functional representation on measurement of functional beta diversity, we also computed PODCAR indices in multidimensional space. Main conclusions BASVIL and PODCAR frameworks led to different results for overall functional beta diversity and their analogous partitioning components. Most of the difference between the two frameworks was due to the functional representation used. The goodness-of-fit measure (mean squared deviation, mSD) to assess the quality of functional spaces showed that the one computed on the basis of the dendrogram used in PODCAR remained lower than that of the functional ordination considered in BASVIL. In addition, only functional turnover derived from the BASVIL framework is independent of difference in functional richness. Finally, BASVIL measured functional variations derived from nested phenomena while PODCAR did not allow separation of this variation derived from richness difference. However, the sensitivity of BASVIL to functionally extreme species may make it difficult to know whether variations of the nestedness-resultant dissimilarity components are due to a turnover with few extreme species or a loss in functional richness. Particular attention with regard to the properties of the two frameworks is required before drawing conclusions regarding processes that structure communities. [ABSTRACT FROM AUTHOR]

Changes in land use and land cover are major drivers of hydrological alteration in the tropical Andes. However, quantifying their impacts is fraught with difficulties because of the extreme diversity in meteorological boundary conditions, which contrasts strongly with the lack of knowledge about local hydrological processes. Although local studies have reduced data scarcity in certain regions, the complexity of the tropical Andes poses a big challenge to regional hydrological prediction. This study analyses data generated from a participatory monitoring network of 25 headwater catchments covering three of the major Andean biomes ( páramo, jalca and puna) and links their hydrological responses to main types of human interventions (cultivation, afforestation and grazing). A paired catchment setup was implemented to evaluate the impacts of change using a 'trading space-for-time' approach. Catchments were selected based on regional representativeness and contrasting land use types. Precipitation and discharge have been monitored and analysed at high temporal resolution for a time period between 1 and 5 years. The observed catchment responses clearly reflect the extraordinarily wide spectrum of hydrological processes of the tropical Andes. They range from perennially humid páramos in Ecuador and northern Peru with extremely large specific discharge and baseflows, to highly seasonal, flashy catchments in the drier punas of southern Peru and Bolivia. The impacts of land use are similarly diverse and their magnitudes are a function of catchment properties, original and replacement vegetation and management type. Cultivation and afforestation consistently affect the entire range of discharges, particularly low flows. The impacts of grazing are more variable but have the largest effect on the catchment hydrological regulation. Overall, anthropogenic interventions result in increased streamflow variability and significant reductions in catchment regulation capacity and water yield, irrespective of the hydrological properties of the original biome. Copyright © 2016 The Authors. Hydrological Processes. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Ecosystems are complex and multivariate; hence, methods to assess the dynamics of ecosystems should have the capacity to evaluate multiple indicators simultaneously., Most research on identifying leading indicators of regime shifts has focused on univariate methods and simple models which have limited utility when evaluating real ecosystems, particularly because drivers are often unknown., We discuss some common univariate and multivariate approaches for detecting critical transitions in ecosystems and demonstrate their capabilities via case studies., Synthesis and applications. We illustrate the utility of an information theory-based index for assessing ecosystem dynamics. Trends in this index also provide a sentinel of both abrupt and gradual transitions in ecosystems. [ABSTRACT FROM AUTHOR]

An index-calibration experiment involves rigorous estimation of animal abundance at a small scale to calibrate a less rigorously derived index of abundance. The efficacy of such index-calibration experiments has been a matter of much controversy. In this study, we develop theoretical models and test them with empirical data on large-scale index-calibration experiments on tigers Panthera tigris to advance our understanding of this controversy., We propose two models that describe the sampling processes involved in typical index-calibration experiments. Using analytical derivations and some simulations, we evaluate the relative roles of these sampling parameters on the [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Research that yields conflicting results rightly causes controversy. Where methodological weaknesses are apparent, there is ready opportunity for discord within the scientific community, which may undermine the entire study., We use the debate about the role of dingoes Canis dingo in conservation in Australia as a case study for a phenomenon that is relevant to all applied ecologists, where conflicting results have been published in high-quality journals and yet the problems with the methods used in these studies have led to significant controversy., To alleviate such controversies, scientists need to use robust methods to ensure that their results are repeatable and defendable. To date, this has not occurred in Australia's dingo debate due to the use of unvalidated indices that rely on unsupported assumptions., We highlight the problems that poor methods have caused in this debate. We also reiterate our recommendations for practitioners, statisticians and researchers to work together to develop long-term, multi-site experimental research programmes using robust methods to understand the impacts of dingoes on mesopredators., Synthesis and applications. Incorporating robust methods and appropriate experimental designs is needed to ensure that conservation actions are appropriately focused and are supported with robust results. Such actions will go a long way towards resolving the debate about the role of dingoes in conservation in Australia, and other, ecological debates. [ABSTRACT FROM AUTHOR]