An evaluation of imagery from an unmanned aerial vehicle (UAV) for the mapping of intertidal macroalgae on Seal Sands, Tees Estuary, UK

The Seal Sands area of Teesmouth is designated a Special Protection Area under the habitats directive because guideline concentrations of nutrients in coastal waters are exceeded. This may be responsible for extensive growth of the green filamentous macroalgae Enteromorpha sp., and literature suggests that algal cover in the intertidal zone is detrimental to the feeding behaviour of wading bird species. Although numerous studies have highlighted the causes and consequences of macroalgal cover, the complex spatial and temporal dynamics of macroalgal bloom growth are not as well understood, and hence there is a need to develop a precise and cost effective monitoring method for the mapping and quantifying of algal biomass. Previous studies have highlighted several image processing techniques that could be applied to high resolution airborne imagery in order to predict algal biomass. In order to test these methods, high resolution imagery was acquired in the Sea լ Sands area using a lightweight SmartPlanes SmartOne unmanned aerial vehicle (UAV) equipped with a near-infrared sensitive 5-megapixel Canon IXUS compact camera, a standard 6-megapixel Canon IXUS compact camera and a Garmin Geko 201 handheld GPS device. Imagery was acquired in November 2006 and June 2007 in order to examine the spectral response of Enteromorpha sp. at different time periods within a macroalgal growth cycle. Images were mosaicked and georeferenced using ground control points located with a Leica 1200 differential GPS and processed to allow for analysis of their spectral and textural properties. Samples of macroalgal cover were collected, georeferenced and their dry biomass content obtained for ground truthing. Although textural entropy and inertia did not correlate significantly with macroalgal biomass, normalised green-red difference index (NGRDI), normalised difference vegetation index (NDVI) and colour saturation computed on the imagery showed a good degree of linear correlation with Enteromorpha sp. dry weight, achieving coefficients of determination in excess of r(^2)= 0.6 for both the November2006 and June 2007 image sets. Linear regression was used to establish predictive models to estimate macroalgal biomass from image spectral properties. Enteromorpha sp. Biomass estimations of 71.4 g DW m(^-2) and 7.9g DW m(^-2) were established for the November 2006 and June2007 data acquisition sessions respectively. Despite a lack of previous biomass quantification for Seal Sands, the favourable performance of a UAV in terms of operating cost and man hours required for image acquisition suggests that unmanned aerial vehicles may present a viable method for the mapping of intertidal algal biomass on an annual basis

Impact of future climate change on water temperature and thermal habitat for keystone fishes in the Lower Saint John River, Canada

Water temperature is a key determinant of biological processes in rivers. Temperature in northern latitude rivers is expected to increase under climate change, with potentially adverse consequences for cold water-adapted species. In Canada, little is currently known about the timescales or magnitude of river temperature change, particularly in large (≥104 km2) watersheds. However, because Canadian watersheds are home to a large number of temperature-sensitive organisms, there is a pressing need to understand the potential impacts of climate change on thermal habitats. This paper presents the results of a study to simulate the effects of climate change on the thermal regime of the lower Saint John River (SJR), a large, heavily impounded, socio-economically important watershed in eastern Canada. The CEQUEAU hydrological-water temperature model was calibrated against river temperature observations and driven using meteorological projections from a series of regional climate models. Changes in water temperature were assessed for three future periods (2030–2034, 2070–2074 and 2095–2099). Results show that mean water temperature in the SJR will increase by approximately ~1 °C by 2070–2074 and a further ~1 °C by 2095–2099, with similar findings for the maximum, minimum and standard deviation. We calculated a range of temperature metrics pertaining to the Atlantic Salmon and Striped Bass, key species within the SJR. Results show that while the SJR will become increasingly thermally-limiting for Atlantic Salmon, the Striped Bass growth season may actually lengthen under climate change. These results provide an insight into how climate change may affect thermal habitats for fish in eastern Canadian rivers

Drone-based Structure-from-Motion provides accurate forest canopy data to assess shading effects in river temperature models

Climatic warming will increase river temperature globally, with consequences for cold water-adapted organisms. In regions with low forest cover, elevated river temperature is often associated with a lack of bankside shading. Consequently, river managers have advocated riparian tree planting as a strategy to reduce temperature extremes. However, the effect of riparian shading on river temperature varies substantially between locations. Process-based models can elucidate the relative importance of woodland and other factors driving river temperature and thus improve understanding of spatial variability of the effect of shading, but characterising the spatial distribution and height of riparian tree cover necessary to parameterise these models remains a significant challenge. Here, we document a novel approach that combines Structure-from-Motion (SfM) photogrammetry acquired from a drone to characterise the riparian canopy with a process based temperature model (Heat Source) to simulate the effects of tree shading on river temperature. Our approach was applied in the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Results show that SfM approximates true canopy elevation with a good degree of accuracy (R2 = 0.96) and reveals notable spatial heterogeneity in shading. When these data were incorporated into a process-based temperature model, it was possible to simulate river temperatures with a similarly-high level of accuracy (RMS

Female teat size is a reliable indicator of annual breeding success in European badgers: Genetic validation

Assessing which females have bred successfully is a central requirement in many ecological field studies, providing an estimate of the effective female population size. Researchers have applied teat measurements previously to assess whether females, in a variety of mammalian species, have bred; however, this technique has not been validated genetically. Furthermore, several analytical techniques are available to classify individuals, but their misclassification rates have not been compared. We used 22 microsatellite loci to assign maternity, with 95% confidence, within a high-density population of European badgers Meles meles, as plural and subterranean breeding means that maternity cannot be inferred from behavioural observations. The teat lengths and diameters of 136 females, measured May–July 1994–2005, from social groups in which all offspring were assigned a mother, were reliable indicators of recent breeding success. A Generalised Linear Mixed Model (GLMM) classified both breeding and non-breeding females with lower error rates than discriminant analyses and crude teat-size criteria. The GLMM model logit probability = −20 + 1.8 month + 1.6 mean teat length + 1.0 mean teat diameter can be applied quickly in the field to assess the probability with which a female badger should be assigned maternity. This is a low-cost measure which, after validation, could be used in other badger or mammalian populations to assess the breeding success of females. This may be a particularly useful welfare tool for veterinary practitioners, especially during badger culls

Fermi surface nesting and topological and magnetoresistance properties of ThX 2 (X=As, Sb, Bi)

In this constantly expanding and evolving era of advanced technology, there is great demand for a compound that boasts a plethora of exotic properties. To procure such a compound, we conducted a thorough analysis of the lattice and electronic properties of several Th-based compounds using first-principle calculations. A Dirac-like crossing displaying nodal line characteristics has been observed in the phonon spectrum of ThAs2, exhibiting nontriviality that has been further confirmed by a nonzero value of the Berry phase. In the analysis of the electronic structure of all the compounds, we have detected nontrivial topological features that were manifested by means of gap plane and Z2 calculations. Moreover, a thorough examination of the compounds further revealed the presence of nodal surfaces, which have been analyzed for their intricate symmetry. The Fermi surface of ThAs2 has been scrutinized for nesting properties through the computation of the real and imaginary components of Lindhard susceptibility, which have shown peaks at the same wave vector, indicating the possibility of a charge density wave in this compound. Furthermore, the application of a 5 T magnetic field has revealed a giant negative magnetoresistance in ThAs2 at 10 K. The coexistence of topological fermions and bosons in the same compound is a rare phenomenon and, combined with the probable presence of charge density waves and negative magnetoresistance, this provides an in-depth, comprehensive understanding of its physical properties and also presents a promising platform for further experimental verifications

Alloparental behaviour and long-term costs of mothers tolerating other members of the group in a plurally breeding mammal

Cooperative-breeding studies tend to focus on a few alloparental behaviours in highly cooperative species exhibiting high reproductive skew and the associated short-term, but less frequently long-term, fitness costs. We analysed a suite of alloparental behaviours (assessed via filming) in a kin-structured, high-density population of plurally breeding European badgers, Meles meles, which are not highly cooperative. Group members, other than mothers, performed alloparental behaviour; however, this was not correlated with their relatedness to within-group young. Furthermore, mothers babysat, allogroomed cubs without reciprocation, and allomarked cubs more than other members of the group (controlling for observation time). For welfare reasons, we could not individually mark cubs; however, the number observed pre-independence never exceeded that trapped. All 24 trapped cubs, in three filmed groups, were assigned both parents using 22 microsatellites. Mothers may breed cooperatively, as the time they babysat their assigned, or a larger, litter size did not differ. Furthermore, two mothers probably allonursed, as they suckled more cubs than their assigned litter size. An 18-year genetic pedigree, however, detected no short-term (litter size; maternal survival to the following year) or long-term (offspring breeding probability; offspring lifetime breeding success) fitness benefits with more within-group mothers or other members of the group. Rather, the number of other members of the group (excluding mothers) correlated negatively with long-term fitness. Mothers may tolerate other members of the group, as nonbreeders undertook more digging. Our study highlights that alloparental care varies on a continuum from that seen in this high-density badger population, where alloparenting behaviour is minimal, through to species where alloparental care is common and provides fitness benefits. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved