24Biodiversity is undergoing unprecedented global decline. Efforts to slow this rate 25 have focused foremost on rarer species, which are at most risk of extinction. 26Less interest has been paid to more common species, despite their greater 27

Artículo de publicación ISIA high proportion of plant species is predicted to be threatened with extinction in the near future. However, the threat status of only a small number has been evaluated compared with key animal groups, rendering the magnitude and nature of the risks plants face unclear. Here we report the results of a global species assessment for the largest plant taxon evaluated to date under the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, the iconic Cactaceae (cacti). We show that cacti are among the most threatened taxonomic groups assessed to date, with 31% of the 1,478 evaluated species threatened, demonstrating the high anthropogenic pressures on biodiversity in arid lands. The distribution of threatened species and the predominant threatening processes and drivers are different to those described for other taxa. The most significant threat processes comprise land conversion to agriculture and aquaculture, collection as biological resources, and residential and commercial development. The dominant drivers of extinction risk are the unscrupulous collection of live plants and seeds for horticultural trade and private ornamental collections, smallholder livestock ranching and smallholder annual agriculture. Our findings demonstrate that global species assessments are readily achievable for major groups of plants with relatively moderate resources, and highlight different conservation priorities and actions to those derived from species assessments of key animal groupsConsejo Nacional de Ciencia y Tecnologia 000000000011820

Many animals regulate their activity over a 24-h sleep-wake cycle, concentrating their peak periods of activity to coincide with the hours of daylight, darkness, or twilight, or using different periods of light and darkness in more complex ways. These behavioral differences, which are in themselves functional traits, are associated with suites of physiological and morphological adaptations with implications for the ecological roles of species. The biogeography of diel time partitioning is, however, poorly understood. Here, we document basic biogeographic patterns of time partitioning by mammals and ecologically relevant large-scale patterns of natural variation in "illuminated activity time" constrained by temperature, and we determine how well the first of these are predicted by the second. Although the majority of mammals are nocturnal, the distributions of diurnal and crepuscular species richness are strongly associated with the availability of biologically useful daylight and twilight, respectively. Cathemerality is associated with relatively long hours of daylight and twilight in the northern Holarctic region, whereas the proportion of nocturnal species is highest in arid regions and lowest at extreme high altitudes. Although thermal constraints on activity have been identified as key to the distributions of organisms, constraints due to functional adaptation to the light environment are less well studied. Global patterns in diversity are constrained by the availability of the temporal niche; disruption of these constraints by the spread of artificial lighting and anthropogenic climate change, and the potential effects on time partitioning, are likely to be critical influences on species' future distributions.cathemeral | night N atural cycles of light and darkness structure the environment of the majority of eukaryotic organisms. The rotation of the Earth partitions time into regular cycles of day and night, and although all points on the Earth's surface receive roughly equal durations of light and darkness over the course of a year, at mid to high latitudes seasonal variation in day length imposes an uneven distribution throughout the annual cycle. During the hours when the sun is below the horizon, there is seasonal and latitudinal variation in the duration of "biologically useful semidarkness" in the form of twilight and moonlight (1), modified by both the lunar cycle and variable cloud cover, providing changing opportunities for animals able to use visual cues for key behaviors including foraging, predator avoidance, and reproduction (2-6). Activity during both daylight and semidarkness may be further constrained by covariance between the natural cycles of light and temperature; the metabolic costs of thermoregulation place constraints on the time available for activity (7). Thermal constraints may limit nocturnal activity when nighttime temperatures are low, and diurnal activity when temperatures are high. Furthermore, energetic constraints may force some species to be active throughout hours of both ...

, is seeking a highly recognized scientific leader to direct and conduct a cutting edge research program in the area of computational exposure science. The position will be located in Research Triangle Park, North Carolina.NERL is leading the development of approaches to exposure science that take advantage of new advances in information and monitoring technology and large new sources of data to improve the rate and scope of exposure assessments. This new approach, "computational exposure science," integrates advances in informatics, chemistry, computer sciences, mathematics, statistics and social and behavioral sciences with new and numerically efficient models to more effectively predict real-world exposures. More information on ORD's NERL can be found at: www.epa.gov/nerlThe incumbent will develop and implement complex computational solutions that facilitate the use of "big data" to develop an understanding of the factors that lead to exposure and to develop rapid exposure and dose exposure for chemicals.In doing so, the incumbent will utilize knowledge of advanced informatics methods, tools and resources in chemistry, environmental science, exposure science, and behavioral science to interpret and understand the importance of various data sets relative to characterizing human and ecological exposure. Salary and Benefits:This is a Title 42 authority appointment. The position is a full-time, renewable, 5-year term appointment. Determination of salary is dependent upon qualifications, experience, and other factors (e.g., current salary, market salary rates). The selected applicant will be eligible for full benefits including relocation expenses, health and life insurance, retirement, and vacation and sick leave.Applicants must be U.S. citizens or permanent residents. EPA is an Equal Opportunity Employer, and selection for this position will be based solely on merit without regard to race, color, religion, age, gender, national origin, political affiliation, disability, sexual orientation, marital or family status or any other non-merit factors.Specific information on the position and instructions for applying can be found at: www.usajobs.gov/ Applications must be received by 11:59 p.m. ET on August 15, 2014, in order to be considered.Applications will not be considered if submitted via USAJOBS.

Artificial light at night is profoundly altering natural light cycles, particularly as perceived by many organisms, over extensive areas of the globe. This alteration comprises the introduction of light at night at places and times at which it has not previously occurred, and with different spectral signatures. Given the long geological periods for which light cycles have previously been consistent, this constitutes a novel environmental pressure, and one for which there is evidence for biological effects that span from molecular to community level. Here we provide a synthesis of understanding of the form and extent of this alteration, some of the key consequences for terrestrial and aquatic ecosystems, interactions and synergies with other anthropogenic pressures on the environment, major uncertainties, and future prospects and management options. This constitutes a compelling example of the need for a thoroughly interdisciplinary approach to understanding and managing the impact of one particular anthropogenic pressure. The former requires insights that span molecular biology to ecosystem ecology, and the latter contributions of biologists, policy makers and engineers.

Since the 1970s nighttime satellite images of the Earth from space have provided a striking illustration of the extent of artificial light. Meanwhile, growing awareness of adverse impacts of artificial light at night on scientific astronomy, human health, ecological processes and aesthetic enjoyment of the night sky has led to recognition of light pollution as a significant global environmental issue. Links between economic activity, population growth and artificial light are well documented in rapidly developing regions. Applying a novel method to analysis of satellite images of European nighttime lights over 15 years, we show that while the continental trend is towards increasing brightness, some economically developed regions show more complex patterns with large areas decreasing in observed brightness over this period. This highlights that opportunities exist to constrain and even reduce the environmental impact of artificial light pollution while delivering cost and energy-saving benefits.

Lightweight drones have emerged recently as a remote sensing survey tool of choice for ecologists, conservation practitioners and environmental scientists. In published work, there are plentiful details on the parameters and settings used for successful data capture, but in contrast there is a dearth of information describing the operational complexity of drone deployment. Information about the practices of flying in the field, whilst currently lacking, would be useful for others embarking on new drone-based investigations. As a group of dronepiloting scientists, we have operated lightweight drones for research in over 25 projects, in over 10 countries, and in polar, desert, coastal and tropical ecosystems, with many hundreds of hours of flying experience between us. The purpose of this paper was to document the lesser-reported methodological pitfalls of drone deployments so that other scientists can understand the spectrum of considerations that need to be accounted for prior to, and during drone survey flights. Herein, we describe the most common challenges encountered, alongside mitigation and remediation actions that increase the chances of safe and successful data capture. Challenges are grouped into the following categories: (i) pre-flight planning, (ii) flight operations, (iii) weather, (iv) redundancy, (v) data quality, (vi) batteries. We also discuss the importance of scientists undertaking ethical assessment of their drone practices, to identify and mitigate potential conflicts associated with drone use in particular areas. By sharing our experience, our intention is that the paper will assist those embarking on new drone deployments, increasing the efficacy of acquiring high-quality data from this new proximal aerial viewpoint.

The existence of fine-grain climate heterogeneity has prompted suggestions that species may be able to survive future climate change in pockets of suitable microclimate, termed 'microrefugia'. However, evidence for microrefugia is hindered by lack of understanding of how rates of warming vary across a landscape. Here, we present a model that is applied to provide fine-grained, multidecadal estimates of temperature change based on the underlying physical processes that influence microclimate. Weather station and remotely derived environmental data were used to construct physical variables that capture the effects of terrain, sea surface temperatures, altitude and surface albedo on local temperatures, which were then calibrated statistically to derive gridded estimates of temperature. We apply the model to the Lizard Peninsula, United Kingdom, to provide accurate (mean error = 1.21 °C; RMS error = 1.63 °C) hourly estimates of temperature at a resolution of 100 m for the period 1977-2014. We show that rates of warming vary across a landscape primarily due to long-term trends in weather conditions. Total warming varied from 0.87 to 1.16 °C, with the slowest rates of warming evident on north-east-facing slopes. This variation contributed to substantial spatial heterogeneity in trends in bioclimatic variables: for example, the change in the length of the frost-free season varied from +11 to -54 days and the increase in annual growing degree-days from 51 to 267 °C days. Spatial variation in warming was caused primarily by a decrease in daytime cloud cover with a resulting increase in received solar radiation, and secondarily by a decrease in the strength of westerly winds, which has amplified the effects on temperature of solar radiation on west-facing slopes. We emphasize the importance of multidecadal trends in weather conditions in determining spatial variation in rates of warming, suggesting that locations experiencing least warming may not remain consistent under future climate change.