In situ adaptive response to climate and habitat quality variation: spatial and temporal variation in European badger (Meles meles) body weight

Variation in climatic and habitat conditions can affect populations through a variety of mechanisms, and these relationships can act at different temporal and spatial scales. Using post‐mortem badger body weight records from 15 878 individuals captured across the Republic of Ireland (7224 setts across ca. 15 000 km²; 2009–2012), we employed a hierarchical multilevel mixed model to evaluate the effects of climate (rainfall and temperature) and habitat quality (landscape suitability), while controlling for local abundance (unique badgers caught/sett/year). Body weight was affected strongly by temperature across a number of temporal scales (preceding month or season), with badgers being heavier if preceding temperatures (particularly during winter/spring) were warmer than the long‐term seasonal mean. There was less support for rainfall across different temporal scales, although badgers did exhibit heavier weights when greater rainfall occurred one or 2 months prior to capture. Badgers were also heavier in areas with higher landscape habitat quality, modulated by the number of individuals captured per sett, consistent with density‐dependent effects reducing weights. Overall, the mean badger body weight of culled individuals rose during the study period (2009–2012), more so for males than for females. With predicted increases in temperature, and rainfall, augmented by ongoing agricultural land conversion in this region, we project heavier individual badger body weights in the future. Increased body weight has been associated with higher fecundity, recruitment and survival rates in badgers, due to improved food availability and energetic budgets. We thus predict that climate change could increase the badger population across the Republic of Ireland. Nevertheless, we emphasize that, locally, populations could still be vulnerable to extreme weather variability coupled with detrimental agricultural practice, including population management.     

陕西长武玉米降水指数保险设计

天气指数保险能有效规避传统农业保险的弊端.本研究基于陕西长武长序列产量数据和气象数据,采用统计分析的方法进行种植面积、产量、单产、趋势产量、相对气象产量以及玉米生育期需供水的分析;采用基于损失的风险评估方法评价种植风险;采用基于Logistic模型的费率厘定方法进行纯费率厘定;根据降水指数和减产率的相关性,设计降水指数...     

Potential use of weather radar to study movements of wintering waterfowl

To protect and restore wintering waterfowl habitat, managers require knowledge of routine wintering waterfowl movements and habitat use. During preliminary screening of Doppler weather radar data we observed biological movements consistent with routine foraging flights of wintering waterfowl known to occur near Lacassine National Wildlife Refuge (NWR), Louisiana. During the winters of 2004–2005 and 2005–2006, we conducted field surveys to identify the source of the radar echoes emanating from Lacassine NWR. We compared field data to weather radar reflectivity data. Spatial and temporal patterns consistent with foraging flight movements appeared in weather radar data on all dates of field surveys. Dabbling ducks were the dominant taxa flying within the radar beam during the foraging flight period. Using linear regression, we found a positive log-linear relationship between average radar reflectivity (Z) and number of birds detected over the study area (P < 0.001, r² = 0.62, n = 40). Ground observations and the statistically significant relationship between radar data and field data confirm that Doppler weather radar recorded the foraging flights of dabbling ducks. Weather radars may be effective tools for wintering waterfowl management because they provide broad-scale views of both diurnal and nocturnal movements. In addition, an extensive data archive enables the study of wintering waterfowl response to habitat loss, agricultural practices, wetland restoration, and other research questions that require multiple years of data. © 2011 The Wildlife Society.     

Fire weather risk differs across rain forest—savanna boundaries in the humid tropics of north‐eastern Australia

Alternative stable state theory has been applied to understanding the control by landscape fire activity of pyrophobic tropical rain forest and pyrophytic eucalypt savanna boundaries, which are often separated by tall eucalypt forests. We evaluate the microclimate of three vegetation types across an elevational gradient and their relative fire risk as measured by McArthur's Forest Fire Danger Index (FFDI). Microclimatic data were collected from rain forest, tall eucalypt forest and savanna sites on eight vegetation boundaries throughout the humid tropics in north Queensland over a 3‐year period and were compared with data from a nearby meteorological station. There was a clear annual pattern in daily FFDI with highest values in the austral winter dry season and lowest values in the austral summer wet season. There was a strong association of the meteorological station FFDI values with those from the three vegetation types, albeit they were substantially lower. The rank order of FFDI values among the vegetation types decreased from savanna, tall eucalypt forest, then rain forest, a pattern that was consistent across each transect. Only very rarely would rain forest be flammable, despite being adjacent to highly flammable savannas. These results demonstrate the very strong effect of vegetation type on microclimate and fire risk, compared with the weak effect of elevation, consistent with a fire–vegetation feedback. This study is the first demonstration of how vegetation type influences microclimate and fire risk across a topographically complex tropical forest–savanna gradient.     

Prioritizing forest fuels treatments based on the probability of high‐severity fire restores adaptive capacity in Sierran forests

In frequent fire forests of the western United States, a legacy of fire suppression coupled with increases in fire weather severity have altered fire regimes and vegetation dynamics. When coupled with projected climate change, these conditions have the potential to lead to vegetation type change and altered carbon (C) dynamics. In the Sierra Nevada, fuels reduction approaches that include mechanical thinning followed by regular prescribed fire are one approach to restore the ability of the ecosystem to tolerate episodic fire and still sequester C. Yet, the spatial extent of the area requiring treatment makes widespread treatment implementation unlikely. We sought to determine if a priori knowledge of where uncharacteristic wildfire is most probable could be used to optimize the placement of fuels treatments in a Sierra Nevada watershed. We developed two treatment placement strategies: the naive strategy, based on treating all operationally available area and the optimized strategy, which only treated areas where crown‐killing fires were most probable. We ran forecast simulations using projected climate data through 2,100 to determine how the treatments differed in terms of C sequestration, fire severity, and C emissions relative to a no‐management scenario. We found that in both the short (20 years) and long (100 years) term, both management scenarios increased C stability, reduced burn severity, and consequently emitted less C as a result of wildfires than no‐management. Across all metrics, both scenarios performed the same, but the optimized treatment required significantly less C removal (naive=0.42 Tg C, optimized=0.25 Tg C) to achieve the same treatment efficacy. Given the extent of western forests in need of fire restoration, efficiently allocating treatments is a critical task if we are going to restore adaptive capacity in frequent‐fire forests.     

Seeing sunlit owls in a new light: orienting Snowy Owls may not be displaying

Snowy Owls Bubo scandiacus often face the sun when sitting on the ground or when perched. Such sun‐orienting has been suggested to represent a visual display to conspecifics but other explanations have not been thoroughly examined. We observed the orientation of wintering Snowy Owls to both the sun and the wind, and their perching behaviour during two winters in central Saskatchewan, Canada. We proposed three new explanations for sun orientation in addition to the display hypothesis: thermoregulation, hunting and defence against predators. On sunny days, 44% of 710 Owls faced the sun; this was non‐random because few did so on overcast days. Sun‐ as opposed to wind‐orienting was strongly associated with weather conditions. Logistic regressions indicated that at temperatures below –13 °C and at wind speeds greater than about 18 km/h, Owls tended to orient to the wind rather than to the sun. The likelihood of wind‐orienting increased if the Owl perched above the ground, whereas the likelihood of sun‐orientating increased slightly when the Owl was sitting on the ground. There was no difference between the sexes in orienting behaviour. Snowy Owls seemed to prioritize wind‐orienting for thermoregulation but the results are also consistent with the idea that sun‐orientation can reduce heat loss. Facing into the sun did not support the hunting explanation because the birds would have been blinded and not able to see prey, but was consistent with the protection explanation if it helps to increase vigilance against enemies. Although we cannot completely rule out the display explanation, the spatial context of sunning Owls and a lack of a sex effect makes it unlikely that this is the main function. Instead, Owls seem to trade‐off wind‐ vs. sun‐orienting according to the prevailing weather conditions and do so mainly to thermoregulate and perhaps to maintain vigilance.     

Factors influencing Manx Shearwater grounding on the west coast of Scotland

Grounding of thousands of newly fledged petrels and shearwaters (family Procellariidae) in built‐up areas due to artificial light is a global problem. Due to their anatomy these grounded birds find it difficult to take off from built‐up areas and many fall victim to predation, cars, dehydration or starvation. This research investigated a combination of several factors that may influence the number of Manx Shearwater Puffinus puffinus groundings in a coastal village of Scotland located close to a nesting site for this species. A model was developed that used meteorological variables and moon cycle to predict the daily quantity of birds that were recovered on the ground. The model, explaining 46.32% of the variance of the data, revealed how new moon and strong onshore winds influence grounding. To a lesser extent, visibility conditions can also have an effect on grounding probabilities. The analysis presented in this study can improve rescue campaigns of not only Manx Shearwaters but also other species attracted to the light pollution by predicting conditions leading to an increase in the number of groundings. It could also inform local authorities when artificial light intensity needs to be reduced.     

Diurnal variation in methane emission in relation to the water table,soil temperature,climate and vegetation cover in a Swedish acid mire

Diurnal variation in the rate of methane emission and its relation to water table depth and macro climate was studied in several plant communities within an acid,Sphagnum dominated, mixed mire in Northern Sweden. Provided that diurnal variation in solar radiation and air temperature occurred, methane fluxes differed during day and night. Diurnal patterns in methane emission rates were found to differ among mire plant communities. In relatively dry plant communities (ridges, minerotrophic lawn), the average nighttime emission rates were 2–3 times higher than the daytime rates during the two periods with high diurnal variation in solar radiation and air temperature. Methane emission was significantly (p < 0.05) related to solar radiation and soil temperature at depths of 5 and 10 cm at all sampling points in the dry plant communities. In the wetter plant communities, no significant difference between daytime and nighttime average methane emission rates were found even though methane emissions were significantly related with radiation and soil temperature at approximately 70% of the sampling points. The increased emission rate for methane at night in the comparatively dry plant communities was probably caused by an inhibition of methane oxidation, owing to the lower nighttime temperatures or to a delay in the supply of root-exuded substrate for the anaerobic bacteria, or by both. The pattern observed in the wet plant communities indicated that methane production were positively related either to soil temperature or light-regulated root exudation.