Lurzengasse 3

Randersacker, Germany

Lurzengasse 3

Randersacker, Germany
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Jones H.,Heriot - Watt University | White A.,Heriot - Watt University | Lurz P.,Lurzengasse 3 | Shuttleworth C.,Bangor University
Ecological Modelling | Year: 2017

The control of invasive species and protection of threatened native species require well-developed policy and species management strategies. Mathematical models provide a key tool that can be used to test, develop and optimise strategies to manage invasive species. We use the native red squirrel and invasive grey squirrel system on the Island of Anglesey, UK, as a case study system in which to parameterise a mathematical model that includes the control of grey squirrels. We develop a stochastic, spatial model that represents the real habitat structure, distribution and linkage on Anglesey and the neighbouring mainland and includes the key population and epidemiological dynamics of the red-grey-squirrelpox system. The model also includes a representation of the trapping and removal of grey squirrels which is parameterised from field data on Anglesey in which grey squirrel were removed and red squirrels reintroduced between 1998–2013. The model is used to assess different management procedures to protect red squirrels from island re-invasion by grey squirrels, including the threat of squirrelpox spread posed by endemic mainland grey populations. The findings have important implications for the conservation of threatened red squirrels throughout the UK and in Europe. Moreover, the modelling framework is based on well-understood, classical models of competitive and epidemiological interactions and therefore the techniques can be adapted and applied more generally to manage the threat of invasive species in a wide range of natural systems. © 2017 Elsevier B.V.

Shuttleworth C.M.,Red Squirrel Trust Wales | Lurz P.W.W.,Lurzengasse 3 | Geddes N.,Forestry Commission | Browne J.,Forestry Commission Wales Coed y Mynydd Forest District
Forest Ecology and Management | Year: 2012

The native red squirrel is being replaced by the introduced North American eastern grey squirrel in the UK. Here, Sitka spruce dominated plantations containing a larch and pine element offer the best long-term opportunity to conserve the red squirrel because they can sustain populations in a forest environment where the competitive advantage of the grey squirrel is reduced. Forest habitat management in designated stronghold areas in England and Scotland is therefore a key strategy for red squirrel conservation. However, the threat of pathogenic tree disease is already leading to changes in forest composition through modified thinning and planting regimes. This has the potential of not only altering habitat suitability for red squirrels but also the competitive ability of grey squirrels. For example, Phytophthora ramorum can severely affect Japanese larch, whilst other common crop species such as Corsican pine, Scots pine and lodgepole pine are all vulnerable to Red Band Needle Blight (Dothistroma septosporum); factors driving significant changes in future forest composition. In this paper we wish to highlight the serious impact of these diseases on established red squirrel management options. We examine proactive and reactive management in three case studies which are attempting to integrate red squirrel habitat requirements into evolving tree disease management protocols. We recommend specific tree species that are both less susceptible to infections and offer potential alternative seed sources for red squirrels, whilst stressing the need for research into grey squirrel exploitation of such crops. We also highlight how the presence of grey squirrels is limiting the use of hazel and other broadleaved species in this context. Finally, a flexible red squirrel management protocol is presented to assist forest managers to integrate red squirrel conservation with the threat posed by Red Band Needle Blight and P. ramorum. © 2012 Elsevier B.V.

White A.,Heriot - Watt University | Bell S.S.,SRUC | Lurz P.W.W.,Lurzengasse 3 | Boots M.,University of Exeter
Journal of Applied Ecology | Year: 2014

There is increasing evidence that disease-mediated invasions are widespread across a range of vertebrate, invertebrate and plant systems. We therefore need a better understanding of the role of disease in managing conservation threats due to introduced and invasive species. Here, we develop a general theoretical model framework to assess the impact of disease-mediated invasion on the viability of conserving native species through refuges taking into account explicit spatial and stochastic processes. The model techniques are applied to the well-documented red and grey squirrel conservation system in the UK as a case study. By combining general and specific modelling approaches, we are able to make management predictions while also gaining an understanding of the processes that underlie population outcomes leading to more robust conservation practice. Model results indicate that in the absence of control of the invading species, native populations are driven to extinction both in the absence of disease (through competition) and more rapidly when the disease is included (through competition and disease processes). When control is applied to reduce the abundance of the invading species, there is a threshold in the level of control, above which the invading population can be prevented from establishing and the native species can be protected. Highly virulent infections - squirrelpox in red squirrels - lead to periodic outbreaks of disease in the native population due to continual invasion attempts from the disease-carrying invader. Infections with low virulence may become established at endemic levels in native populations. Therefore, an important finding is that the disease can spread through the native species even when the invading species is prevented from establishing. The benefits of increased density may be countered by an increased risk of disease outbreaks. Therefore, a critical message is that there is a correlation between native density (and therefore habitat quality) and the impact of disease 'harmful' to native species. Control of the invading species to prevent it establishing in strongholds can protect the native species from exclusion, but may not protect it from disease outbreaks. Synthesis and applications. Disease outbreaks in the absence of the invading species can result in significant population crashes and therefore represents a serious threat because it contributes to the risk of population extinction by suppressing the size of the population making it more vulnerable to extinction through stochastic processes. Disease outbreaks in the absence of the invading species can result in significant population crashes and therefore represents a serious threat because it contributes to the risk of population extinction by suppressing the size of the population making it more vulnerable to extinction through stochastic processes. © 2014 British Ecological Society.

Signorile A.L.,Imperial College London | Signorile A.L.,UK Institute of Zoology | Wang J.,UK Institute of Zoology | Lurz P.W.W.,Lurzengasse 3 | And 4 more authors.
Diversity and Distributions | Year: 2014

Aim: This study investigates how founder size may affect local genetic diversity and spatial genetic structure of the invasive American eastern grey squirrel (Sciurus carolinensis) in European areas. It also examines whether dispersal propensity and invasion rate may be related to founder size, genetic diversity and structure. Location: Piedmont, Italy; Northern Ireland, Northumberland and East Anglia, UK. Methods: Across the invaded range in Europe, 315 squirrels from 14 locations, grouped in four areas, were sampled and examined at 12 highly polymorphic microsatellite loci. We estimated both genetic variation and population structure using AMOVA, Mantel tests and Bayesian analysis. We also estimated migration rates and range expansion rates. Results: Genetic diversity varied in accordance with numbers of founders across populations. For instance, the Italian population had the smallest founder size and lowest genetic variability, whereas Northumberland had high values for both. Significant levels of genetic differentiation were observed in all the examined regions. Gene flow, migration and population range expansion rate were also higher in England and Ireland than in Italy. Main conclusions: Populations descending from human-mediated releases of few individuals were more genetically depauperate and more differentiated than populations established from a greater number of founders. Propagule pressure is therefore a significant factor in squirrel invasions. There is a trend whereby larger founder sizes were associated with greater genetic diversity, more dispersal, less local genetic differentiation and faster range expansion rate in squirrels. These findings have important management implications for controlling spread rate of squirrels and other invasive species: good practice should prioritize preventing further releases and the merging of genetically distinct populations as these events can augment genetic diversity. © 2014 The Authors. Diversity and Distributions published by John Wiley & Sons Ltd.

Flaherty S.,CONICET | Lurz P.W.W.,Lurzengasse 3 | Patenaude G.,University of Edinburgh
Journal of Applied Remote Sensing | Year: 2014

LiDAR remote sensing allows the direct retrieval of vegetation structure parameters and has been widely used to assess habitat quality for various species. The aim of this study is to test whether LiDAR can help in providing estimates of habitat suitability over larger scales and inform conservation management planning in stronghold areas of an endangered forest mammal, the red squirrel (Sciurus vulgaris L.). The Eurasian red squirrel is endangered in the UK and under strict legal protection. Hence, long-term habitat management is a key goal of the UK conservation strategy. This involves understanding habitat preferences of the species. In a previous study, we demonstrated the importance of forest structure for red squirrels' habitat preference. We used a general linear model (GLM) to relate the distribution and abundance of squirrel feeding signs to mean canopy closure, mean tree height, and the total number of trees at the plot level. However, this analysis was limited to a few sample areas. In the current study, we implement the GLM using LiDAR-derived explanatory variables in Abernethy Forest. Results suggest that when forest structure is considered, only 27% of the total forest area is highly suitable for red squirrel. Implications for management are discussed. © 2014 SPIE.

Rodents are traded as pet species, a practice that frequently results new introduced populations. This is particularly true for tree squirrels where, often, only a few founders can establish viable colonies. Here, we review the worldwide introductions, ecology and impacts of two tree squirrel species, Callosciurus erythraeus and Callosciurus finlaysonii, and discuss the elements of a strategy to reduce squirrel introductions and settlements. C. erythraeus has established viable populations Argentina, France, The Netherlands, Hong Kong and Japan. An introduction to Belgium may have been stopped successfully. C. finlaysonii has been introduced to Italy, Singapore and Japan. After 1950, the mean number of introduction events was one every two years. The most evident damage caused by these species is bark stripping that can be severe and may significantly impact trees and timber plantations. Data on negative impacts to native species are reported but have not yet been formally quantified. Both squirrel species carried with them parasites from the native range into the new habitats, leading to the introduction of other species. The ability of tree squirrels to establish themselves successfully, often from only a few founders, combined with their human appeal make them high-risk species, and the pet trade should be considered as a high-risk pathway for new introductions. A proactive approach to preventing new introductions should therefore include trade restrictions, and should be combined with public education initiatives at national and European scales. Tree squirrels represent an 'alien species conundrum'. Experience from the UK and Italy has shown that if action is delayed until introductions are recognized as a problem, it is generally too late to control populations effectively, due to logistic, legal or economic reasons, or due to lack of public support. the case of new populations, a rapid response mechanism is therefore critical. Once established, populations may become invasive and difficult or impossible to control. © 2011 Mammal Society/Blackwell Publishing.

Bosch S.,Metterstrasse 16 | Lurz P.W.W.,Lurzengasse 3
Hystrix | Year: 2013

We present unique footage and an analysis of recorded data of a free-ranging red squirrel building its drey in February 2012 inside a nestbox fitted with a hidden camera. Drey construction occurred over a period of three days that was dominated by an initial phase of transporting material; this then shifted more and more to construction of the outer twigg-shell of the drey and to the processing of materials for the soft inner lining and core of the drey. Total construction time in terms of minutes of red squirrel presence logged was 3.6 hours. Construction occurred after a period of 4-5 days of dry weather and at temperatures that were well above 0° C. After the squirrel abandoned the drey, the dry material was explored and used by songbirds indicating the importance of accessible structures and dry construction material for other species. The video is available as supplemental material in the online version. © 2014 Associazione Teriologica Italiana.

Modern camera technology opens exciting opportunities for new and unexpected observations of animal behaviour and data collection. Despite the existence of a large number of studies that employed cameras, there is a lack of technically-oriented overviews and reports where equipment was used continuously. Here, we therefore illustrate the opportunities camera technology offers, and collate our extensive experiences with songbirds and small mammals using a specially designed camera system for observations. Small portable cameras present clear advantages such as an affordable price, adaptability to requirements, reliability and high quality images. Despite emissions of infrared-light and heat, camera-equipped nest boxes are accepted by animals for sleeping or breeding without problems. However, it is important to accept that cameras do alter the conditions inside the nest boxes. CCD-cameras are in our experience preferable to CMOS-cameras. Picture quality is comparable for both cameras but the former emit less heat. The continuous use of cameras in next boxes over several years also showed the problems one encounters when employing the technology. Dirt, wasp nests, spiders or gnawed cables by mice or squirrels can all interrupt data collection. Some research questions require motion-triggered images, however false-positives can be caused by light-changes inside or outside of the nest or at the entrance, precipitation, moving vegetation (e.g. branches or leaves), spiders or insects. In addition, poor picture quality can occur during overcast skies or in twilight, as cameras switch to IR-illumination in low light levels. In order to motivate people to use cameras themselves we offer advice and tips based on our experiences as well as legal and organisational information. With the increasing use of camera technology in research and citizen science, we also propose the creation of a code of conduct to avoid negative impacts on study animals and offer initial suggestions based on the current work. © DO-G, IfV, MPG 2016.

Flaherty S.,University of Edinburgh | Lurz P.W.W.,Lurzengasse 3 | Patenaude G.,University of Edinburgh
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

The native Eurasian red squirrel is considered endangered in the UK and under strict legal protection. Long term habitat management is a key goal of the UK conservation strategy. The importance of forest structural parameters for red squirrels habitat mapping was previously demonstrated: a General Linear Model (GLM) was used to relate the number of cones stripped by squirrels to mean canopy closure, mean tree height and total number of trees at the plot level, all significant predictors and explaining 43% of the variance in the number of stripped cones. The main aim of this study is to implement the GLM using LiDAR derived explanatory variables and to assess habitat suitability at Abernethy Forest, one of the proposed red squirrel strongholds in the UK. LiDAR-based GLM performance was explored by assessing the correlation between field-predicted and LiDAR-predicted number of stripped cones (Spearman rank correlation coefficient = 0.59; n=32, P< 0.00). Finally, habitat suitability maps were generated. Results suggest that when forest structure is considered, only 27% of the total forest area at Abernethy is suitable for red squirrel. © 2012 SPIE.

Flaherty S.,University of Edinburgh | Close A.,Northumbria University | Lurz P.W.W.,Lurzengasse 3
Forestry | Year: 2012

The native Eurasian red squirrel is considered endangered in the UK and under strict legal protection. Long-term habitat management is a key goal of the UK conservation strategy. Current selection criteria of reserves and subsequent management mainly consider species composition and food availability. However, there exists a critical gap in understanding and quantifying the relationship between squirrel abundance, their habitat use and forest structural factors. This is partly a result of limited availability of structural data along with cost-efficient data collection methods. We investigated the relationship between structural characteristics and squirrel feeding activity in Scots pine. Field data were collected from two study areas: Abernethy and Aberfoyle Forest. Canopy closure, diameter at breast height, tree height and number of trees were measured in 56 plots. Abundance of squirrel feeding signs was used as an index of habitat use. We used a generalized linear model to model the response of cones stripped by squirrel in relation to field-collected structural variables. Results show that forest structural characteristics are significant predictors of feeding sign presence; canopy closure and number of trees contribute to explain 43 per cent of the variation in stripped cones. Our findings critically highlight the need to consider stand structure in management for red squirrels.

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