Climate change refugia for the flora and fauna of England

A variety of evidence suggests that species have, in the past, been able to withstand the effects of climatic change in localised environments known as refugia, where specific environmental conditions acted as a buffer against broader-scale climatic changes. Therefore, an important question for conservation is whether refugia might exist under current and future anthropogenic climate change. If there are areas that are likely to remain relatively climatically stable and so enable species to persist despite climate change making surrounding areas unsuitable, identifying and protecting these places will be an important part of future conservation strategies. This report is part of a project that is investigating this question. The report was commissioned to identify the characteristics of potential refugia, to investigate evidence for the existence of contemporary refugia by analysing patterns of local persistence and disappearance of over 1000 species across a range of taxa, and to identify sites in England with the potential to function as refugia for different taxonomic groups at a range of spatial scales

Characterising peatland carbon balance estimates using freely available Landsat ETM+ data

We demonstrate the potential of using freely available satellite data from the Landsat ETM+ sensor for generating carbon balance estimates for lowland peatlands. We used a lowland ombrotrophic peatland in the UK as our test site representing a range of peatland conditions. A literature survey was undertaken to identify the simplest classification schema that could be used to distinguish ecohydrological classes for carbon sequestration on the peatland surface. These were defined as: active raised bog, Eriophorum-dominated bog, milled unvegetated peat and drained or degraded bog, with bracken and Carr woodland to define the bog edges. A maximum likelihood classifier (MLC) was used to map the spatial distribution of the six classes on the peatland surface. A Landsat ETM+ band-5 derived brightness-texture layer created using geostatistical methods greatly improved classification accuracies. The results showed the best accuracy of the MLC, when compared to finer scale methods, with Landsat ETM+ bands alone was 74%, which increased to 93% when including the brightness-texture layer. An estimate of carbon sequestration status of the site was performed that showed good agreement with the results of a finer-scale-based estimate. The coarse-scale map estimating ?12?000?kg carbon and fine scale map estimating +23?000?kg carbon per annum. We conclude that with further development of our tool, if textural measures are used alongside optical data in MLC, it is possible to achieve good quality estimates of carbon balance status for peatland landscapes. This represents a potentially powerful operational toolkit for land managers and policy makers who require spatially distributed information on carbon storage and release for carbon pricing and effective land management

The elusive winter engineers: structure and materials of hazel dormouse hibernation nests

Trade-offs between specialist use of particular resources and opportunistic use of widespread materials may present different strategies for survival. Hazel dormice Muscardinus avellanarius are arboreal mammals that in Great Britain hibernate from late autumn to mid spring in nests that are specially built at ground level. Hibernation nests are rarely encountered, and little is known about the types of construction or materials used. Specifically, it is not known whether nest materials are selected opportunistically, based on their availability, or are specialised to suit local environmental conditions. We therefore conducted a study to characterise the main materials used to construct these nests, explore the distances travelled to col lect materials and investigate whether regional climate and/or local microclimate have an impact on the types of nests built. Thirty-three hibernation nests were located through radio-tracking, systematic searches and incidental finds. Struc turally, hibernation nests were built similarly to summer nests and were most commonly constructed with an outer layer of leaves and distinct core section made of woven material. We found no correlation between nest type and the temperature recorded at nest sites. Nests were built using a mean of two materials per nest, which were both in every case available within 3m of the nest. The most frequently used materials were bracken, hazel and beech leaves, and grasses. Dormice were flexible in their use of nest materials, using various materials harvested very locally. However, dormice travelled further to collect grasses, ferns, bracken and honeysuckle, and these materials made up most of the nests in which they were found. There were also positive correlations between material abundance and usage, and suitable materials for hibernation nest construction were therefore readily available within their home range.Peer reviewe

Combining LiDAR and IKONOS data for eco-hydrological classification of an ombrotrophic peatland

This paper presents the results of a study aimed at improving the spatial representation of eco-hydrological communities on ombrotrophic (rain-fed) peatlands. Remote sensing techniques have shown potential for peatland monitoring but most previous work has focussed on spectral approaches. Such methods often result in poor discrimination of cover types and also neglect information on the presence of peatland microtopes (e.g. hummocks and hollows), which show strong links to hydrological condition, biodiversity and carbon sequestration. Spatial information on surface structure is therefore a useful proxy for peatland condition. The paper first demonstrates how airborne LiDAR data can provide such information. Secondly, we apply a combined multispectral-structural approach using IKONOS and airborne LiDAR data to the mapping of peatland condition classes (defined by the lowland raised bog inventory) at Wedholme Flow, Cumbria, UK. LiDAR data were pre-processed so that spatial estimates of minimum and maximum land surface height, variance and semi-variance (from semivariogram analysis) were extracted. These were assimilated into a spectral classification procedure with an IKONOS dataset where thematic outputs from per-pixel maximum likelihood classification were compared. Field ecological survey data were used to validate the results which showed considerable improvements in thematic separation of peatland eco-hydrological classes, when spatially-distributed measurements of LiDAR variance or semivariance at 5 m lag were included. Of key importance was the improved delineation of management classes (Eriophorum bog, active raised bog, Rhynchospora alba communities, and Calluna- and Erica-dominated degraded raised bog). The paper demonstrates how combined textural-optical approaches can offer improvements in land cover mapping products in areas where reliance on purely spectral discrimination approaches would otherwise result in considerable thematic uncertainty

Range expansion through fragmented landscapes under a variable climatee

Ecological responses to climate change may depend on complex patterns of variability in weather and local microclimate that overlay global increases in mean temperature. Here, we show that high-resolution temporal and spatial variability in temperature drives the dynamics of range expansion for an exemplar species, the butterfly Hesperia comma. Using fine-resolution (5 m) models of vegetation surface microclimate, we estimate the thermal suitability of 906 habitat patches at the species' range margin for 27 years. Population and metapopulation models that incorporate this dynamic microclimate surface improve predictions of observed annual changes to population density and patch occupancy dynamics during the species' range expansion from 1982 to 2009. Our findings reveal how fine-scale, short-term environmental variability drives rates and patterns of range expansion through spatially localised, intermittent episodes of expansion and contraction. Incorporating dynamic microclimates can thus improve models of species range shifts at spatial and temporal scales relevant to conservation interventions.Natural Environment Research Council (NERC

Characterising inter-annual variation in spatial pattern of thermal microclimate in a UK upland using a combined empirical–physical model

Temperature exerts a fundamental control on ecosystem function, species’ distributions and ecological processes across a range of spatial scales. At the landscape scale, near-surface air temperature may vary spatially over short distances, particularly inmountainous regions. Both themagnitude and spatial pattern of surface temperature may vary on diurnal, seasonal and inter-annual timescales. Furthermore, temperatures measured at the surface of vegetation, influenced by the energy balance of the surface, can differ considerably from air temperature. In order to explore spatial patterns in temperature across the MoorHouse sector of theMoorHouse—Upper Teesdale National Nature Reserve (NNR), Northern Pennines, UK,wederived anempirical linear regressionmodel to predict airtemperature at1 mheight as a functionof landscape metrics derived from a digital elevation model (DTM), and coupled this to an existing physical land-surfacemodel (JULES) in order to predict andmapthermal climate at the vegetation surface across the study area. Spatial patterns in temperature associated with altitudinal lapse rate, katabatic flowand a local fo¨hn effect were incorporated into the regression model. JULES was driven using spatially distributed air temperatures from the empirical model, along with distributed solar and long-wave radiation flux estimates adjusted for surface slope and aspect, and sky-view in order tomodel the surface energy balance and predict thermal climate at the vegetation surface (skin temperature). Aggregate properties such as annual degree days above 5 8C (GDD5), number of ‘‘frost days’’ when the temperature fell below 0 8C (FD0) and number of ‘‘severe frost days’’ when the minimumtemperature fell below5 8C (FD5) were mapped across the reserve for the years 1994–2006. Spatial mapping of surface temperature revealed differences in the 12-year average spatial pattern betweenGDD5, FD0 and FD5, and differences in the spatial patterns of FD0 and FD5 between different years, depending on the relative strength of lapse rates, temperature inversions and the fo¨hn effect. The location of ‘‘warm’’ and ‘‘cool’’ microclimates within the study area varies depending on the dominant atmospheric conditions in a given year and on the thermal property of interest.While GDD5 tended to decrease and FD0 increasedwith increasing altitude in all years, following the gradients in average temperature, the magnitude of these relationships varied considerably between years. FD5 increased in some years and decreased in others, due to the influence of temperature inversions during extreme cold temperature events. We conclude, that in order to predict the landscapescale response of species and communities to climatic change in upland areas accurately, it will be necessary to take into account changes in the frequency and magnitude of different synoptic atmospheric conditions under future climate scenarios

Mikromekaaninen oskillaattori

Tässä diplomityössä tutustuttiin kapasitiivisesti kytketyllä mikromekaanisella resonaattorilla stabiloidun sähkömekaanisen oskillaattorin teoriaan: resonaattorin mekaniikkaan ja vahvistimen elektroniikkaan. Esitetyn teorian pohjalta suunniteltiin ja rakennettiin sähkömekaaninen 500 kHz:n Pierce-oskillaattori. Prototyypin toiminta demonstroitiin mittauksin. Prototyypin mittauksissa todennettiin mikromekaanisen oskillaattorin värähtelytaajuuden ja -amplitudin riippuvuus resonaattorin biasjännitteestä; mittaustulokset olivat ennusteiden mukaiset. Oskillaattorin värähtelytarkkuutta kuvaava vaihekohina mitattiin tarkoitukseen suunnitellulla laitteistolla. Mitattu vaihekohina oli -123dBc@SkHz. Prototyypissä käytettiin palkkiresonaattoria, jonka epälineaarisuuden seurauksena oskillaattorin ulostulo oli säröytynyt. Työssä pohdittiin myös fysikaalisia rajoja palkkiresonaattoriin perustuvan mikromekaanisen oskillaattorin suorituskyvylle