The American Grey Squirrel is an alien invasive species that has been released many times in several areas across the world for recreational purposes. In Britain, following multiple introductions from the USA and Canada, grey squirrel populations have proven to be a major threat for both wildlife and agroindustry activities and their spread has been quick and unaffected by control programs. In both Ireland and the Piedmont in Italy, on the other hand, only one introduction, each of very few individuals, is supposed to have occurred within the last century and squirrel spread has proven to be relatively slow in both countries. The origin and founding size of the other three Italian populations is still unclear. We hypothesize that low genetic variation and inbreeding depression contribute comparably to differential expansion rates in Italy, Ireland, and the UK compared to ecological factors. The main aim of my PhD project is to evaluate the inbreeding coefficient of European  grey squirrel populations by examining the heterozigosity at specific loci through microsatellite analysis of DNA. Outcomes will be correlated to spread rates. It will be important to include in this analysis the role played by ecological corridors and other ecological factors in squirrels’ spread and hence an analysis of several environmental determinants will be simultaneously carried out. If expansion rate of grey squirrels in Italy are strongly limited by low genetic diversity, it will be important to prevent the four separate Italian populations from merging and thereby potentially increasing their genetic diversity and speeding their joint expansion rate.

This Ph.D. project has been funded by the UK Natural Environment Research Council and will be undertaken at Imperial College London and the Institute of Zoology under the supervision of Dr Dan Reuman, Dr Chris Carbone, Dr Jinliang Wang, and Dr. Tony Sainsbury. Dr Sandro Bertolino of the University of Turin and Dr. Peter Lurz of Newcastle University are outside supervisors and collaborators.

The red squirrel (Sciurus vulgaris), the only squirrel species native to the UK, is now considered endangered, is listed in the UK Biodiversity Action Plan and is also under legal protection.

The future of red squirrel conservation will depend on the careful selection and management of suitable reserve areas. Several studies have demonstrated the importance of tree species composition and age (related to food availability) on habitat use. However, there exists a critical gap in understanding and quantifying the relationship between squirrel abundance, their habitat use and forest structural factors such as canopy connectivity, tree densities, height heterogeneity.

The aim of this research project is therefore to address this research gap. Methodologically, the aim is to develop remotely-sensed approaches to facilitate data capture on habitat suitability. Ground-based assessment of habitat suitability in large semi-natural Scottish woodlands is prohibitively expensive at national scales. Remote Sensing (RS) enables cost efficient canopy characteristics assessment at such scales.

To achieve these aims, the project objectives are:

- Create a ground-based forest structure and squirrel feeding activity database for Queen Elizabeth Forest Park, Aberfoyle.

- Develop relationships between key stand structure variables and squirrel feeding behaviour for Norway spruce (Picea abies); Lodgepole pine (Pinus contorta) and Scots pine (Pinus sylvestris)

-Generate RS based methodologies for the extraction of key forest structural parameters relating to habitat suitability.

A new study has started at the Insitute of Zoology, London on whether inbreeding affects the disease status of squirrelpox virus in red squirrels.

Does inbreeding affect the disease status of red squirrels (Sciurus vulgaris) with respect to squirrelpox virus (SQPV)?

Project duration: 12 months, starting June 2009.

Background: From its previous status as widespread and abundant throughout the U.K, the red squirrel has now suffered a dramatic decline over the last 100 years. This has been coupled with extensive local extinctions and, in England and Wales, red squirrels now exist only in isolated populations. Red squirrel populations remain in decline with the causal factors appearing to be infectious disease and competition for juvenile recruitment with the introduced grey squirrel. There is good evidence that the grey squirrel is the reservoir of the squirrelpox virus (SQPV) – a lethal virus to red squirrels and one which is considered to be a significant threat to the conservation of red squirrels in the U.K.

Isolated populations of red squirrels have been shown to have low within population genetic diversity. This inbreeding effect has been linked to susceptibility to pathogens in other species, and therefore individual red squirrels showing loss of heterozygosity may have increased susceptibility to SQPV.

Project Summary: This project aims to investigate the relationship between individual genetic diversity and susceptibility to squirrelpox virus by:

• Identifying, by post-mortem examination and electron microscopy, individuals infected with SQPV.
• Assessing the heterozygosity of individuals by microsatellite typing at specific loci.
• To assess whether inbreeding influences the adrenal gland size in individual red squirrels, which would suggest that heterozygosity may affect immune function.

We hope the results of this project will serve to inform decision making in red squirrel conservation and help in the provision of effective conservation measures to ensure genetically viable, self-sustaining populations.

This project is being funded by the Peoples Trust for Endangered Species Mammal Internship Grant 2009 and will be undertaken at the Institute of Zoology under the supervision of Dr Tony Sainsbury and Dr Bill Jordan.

For further information please contact Melissa Marr, Research Intern, Zoological Society of London, Regents Park, London, NW1 4RY.

The Alpine Squirrel Population Ecology Research project celebrates 10 years. Run by Italian scientists, the project is building a fascinating long-term data set on the population dynamics and food resources of red squirrels Sciurus vulgaris living in montane and subalpine conifer forests. There are new opportunities for post-graduate biologists to join in the research programme.

The ASPER (Alpine Squirrel Population Ecology Research) Project: celebrating 10 years

The ASPER studies have been going on for 10 years and are entering a stage whereby the time-series data on population demography and abundance of food resources are suitable to explore habitat selection and local adaptation by red squirrels to the different montane and subalpine conifer forests-types that form the heterogeneous landscape of one of Europe’s biodiversity hotspots, the Alps. Acquiring this knowledge is essential to define red squirrel sanctuaries that must be, at all costs, kept free from expanding grey squirrel populations.

Current research is continuing at 6 study sites: 4 in Central Lombardy Alps and 2 in the Western Alps. For the period 2009-2012 the project leaders are looking for early-stage researchers from EU countries which are interested to participate to the ASPER project. Potential funding might be available in the FP-7-PEOPLE Mari Curie Actions. This EU-program offers fellowships and grants at two levels:

• Activity 1: Initial Training of Researchers = 1 MARIE CURIE ACTION: INITIAL TRAINING NETWORKS (ITN): Post-graduate Ph.D. grants for Early-stage Researchers that want to obtain a Ph.D. degree in a European country different from where they resided or carried out main activity in the past 12 months. For the moment there are no calls open; nxet call is expected for second half of 2009.
• Activity 2: Life-long Training and Career Development = 2.1 MARIE CURIE ACTION: INTRA-EUROPEAN FELLOWSHIPS FOR CAREER DEVELOPMENT (IEF)

Call Reference FP7-PEOPLE -2009-IEF (OJ CO63 of 18 march 2009): deadline of this call 18/08/2009 at 17:00 Brussels local time, see the information package online.

Introduction and objective of the action: to support the career development of experienced researchers (post-doc) at different stages of their careers, and seeks to enhance their individual competence diversification in terms of skill acquisition at multi- or interdisciplinary level. Support is foreseen for individual, trans-national, intra-European fellowships awarded directly at Community level, to the best or most promising researchers from Member States, based on an application made by the researchers in conjunction with the host organisations.

Technical content/scope:

Projects and participants: This action provides financial support for advanced training and trans-national mobility, for a period of 12 to 24 months (full-time equivalent), for individual projects presented by experienced researchers active in Member States in liaison with a host organisation from another Member State or Associated country. The research topic will be chosen by the researcher in collaboration with the host, with a view to achieving a diversification of competences and developing his/her career in a European context.

The ASPER project is run by University of Insubria, Varese (Università degli Studi dell’Insubria, Varese), Italy (host organisation for the project); the name of the Principal Investigator (PI) is Lucas Wauters, the head of the research group is Prof. Guido Tosi.

We propose the following project for an IEF grant:

Proposed title: Interactive effects of consumer fitness, genetic variation and parasites, on producer-consumer dynamics in pulsed resource systems.

Proposal duration: 24 months

Proposal summary

An individual’s fitness is the result of how it optimises resource allocation to survival and reproduction. Reproduction and survival are often constrained by the distribution and abundance of critical resources, especially food. In many temperate ecosystems, resources occur in unpredictable pulses, creating lagged responses in successive trophic levels. So far, consumer dynamics have been mainly explored by studying the effect of producer dynamics on consumer demography. However, the mechanisms underlying the consumer’s response and their interaction with seasonal, age-related and other sources of variation in individual condition, remain largely unexplored. Moreover, some seed-predators seem to have co-evolved with the trees they feed on and anticipate (summer) reproduction, a still poorly understood and controversial response. Therefore, we propose a multi-disciplinary research project to demonstrate that anticipatory reproduction to synchronise population growth with the resource pulse is the result of co-evolution of seed predators with the masting strategy of the trees. If indeed a result of natural selection, the mechanism should occur in different habitats.

The general aim of this IEF project is to explore behavioural mechanisms and phenotypic characteristics that allow squirrels (study species) to anticipate reproduction and start reproductive investment in a period of low availability of high-energy food resources.

The major objectives are: (1) continued monitoring of the producer-consumer dynamics in red squirrels to obtain 11-13 year time-series; (2) focus on the role of individual condition and how it interacts with parasitism rates and individual genetic quality; and (3) explore the role of dispersal in local population dynamics, in different habitats covering an isolation gradient, using a combination of Capture-Mark-Recapture and genetic markers.

The principal role of the post-doc fellow is objective 2. We believe this is a highly innovative aspect of the entire study, since up to date, the majority of studies in population and behavioural ecology have concentrated on one or a few populations of a species, and rarely behavioural studies are combined with demographic ones to explore the mechanisms that drive the dynamics of populations. Even when the role of individual variation in population dynamics is investigated, there are few studies that combine different disciplines such as capture-mark-recapture, genetics, and parasite studies. For example, we found no studies on vertebrates that combined genetic measures of an individual’s condition (e.g. heterozygosity measured by microsatellites), parasite intensity, morphological phenotypic measures of condition and fitness parameters.

Any post-doc interested in developing such a research project is invited to contact me:

Lucas Wauters, PI ASPER project

The ASPER project publications

• BERTOLINO S, WAUTERS LA, DE BRUYN L, CANESTRI-TROTTI G (2003) Prevalence of coccidia parasites (Protozoa) in red squirrels (Sciurus vulgaris): effects of host phenotype and environmental factors. Oecologia 137: 286-295.
• WAUTERS LA, ZANINETTI M, TOSI G, BERTOLINO S (2004) Is coat-clour polymorphism in Eurasian red squirrels (Sciurus vulgaris L.) adaptive? Mammalia 68(1): 37-48.
• BERTOLINO S, VIZZINI A, WAUTERS LA, TOSI G (2004) Consumption of hypogeous and epigeous fungi by the red squirrel (Sciurus vulgaris) in subalpine conifer forests. Forest Ecology and Management 202: 227-233.
• TRIZIO I, CRESTANELLO B, GALBUSERA P, WAUTERS LA, TOSI G, MATTHYSEN E, HAUFFE HC (2005) Geographical distance and physical barriers shape the genetic structure of Eurasian red squirrels (Sciurus vulgaris) in the Italian Alps. Molecular Ecology 14: 469-481.
• WAUTERS LA, BERTOLINO S, ADAMO M, VAN DONGEN S, TOSI G (2005) Food shortage disrupts social organization: the case of red squirrels in conifer forests. Evolutionary Ecology 19: 375-404.
• TATTONI C, PREATONI DG, LURZ PWW, RUSHTON SP, TOSI G, BERTOLINO S, MARTINOLI A, WAUTERS LA (2006) Modelling the expansion of a grey squirrel population: implications for squirrel control. Biological Invasions 8: 1605-1619 (doi:10.1007/s10530-005-3503-z).
• MOLINARI A, WAUTERS LA, AIROLDI G, CERINOTTI F, MARTINOLI A, TOSI G (2006) Cone selection by Eurasian red squirrels in mixed conifer forests in the Italian Alps. Acta Oecologica 30: 1-10 (doi:10.1016/j.actao.2005.11.004).
• WAUTERS, LA, PREATONI DG, MOLINARI A, TOSI G (2007) Radio-tracking squirrels: performance of home range density and linkage estimators with small range and sample size. Ecological Modelling 202: 333-344 (doi:10.1016/j.ecolmodel.2006.11.001).
• WAUTERS LA, VERMEULEN M, VAN DONGEN S, BERTOLINO S, MOLINARI A, TOSI G, MATTHYSEN E (2007) Effects of spatio-temporal variation in food supply on red squirrel Sciurus vulgaris body size and body mass and its consequences for some fitness components. Ecography 30: 51-65.
• DI PIERRO E, MOLINARI A, TOSI G, WAUTERS LA (2008) Exclusive core areas and intrasexual territoriality in Eurasian red squirrels (Sciurus vulgaris) revealed by incremental cluster polygon analysis. Ecological Research 23: 529-542 (doi: 10.1007/s11284-007-0401-0).
• WAUTERS LA, GITHIRU M, BERTOLINO S, MOLINARI A, TOSI G, LENS L (2008) Demography of alpine red squirrel populations in relation to fluctuations in seed crop size. Ecography 31: 104-114 (doi: 10:1111/j.2007.0906-7590.05251.x).
• MARI V, MARTINI S, ROMEO C, MOLINARI A, MARTINOLI A, TOSI G, WAUTERS LA (2008) Record litter size in the Eurasian red squirrel (Sciurus vulgaris). Hystrix It. J. Mamm. 19: 61-65.
• KVÁC M, HOFMANNOVÁ L, BERTOLINO S, WAUTERS L, MODRÝ D (2008) Natural infection with two genotypes of Cryptosporidium in red squirrels (Sciurus vulgaris) in Italy. Folia Parasitologica 55: 95-99.
• SALMASO F, MOLINARI A, DI PIERRO E, GHISLA A, MARTINOLI A, PREATONI D, SERINO G, TOSI G, BERTOLINO S, WAUTERS LA (2009) Estimating and comparing food availability for tree-seed predators in typical pulsed-resource systems: alpine conifer forests. Plant Biosystems 143: xx-xx (in press).
• BERTOLINO S, WAUTERS LA, PIZZUL A, MOLINARI A, LURZ PWW, TOSI G (2009) A general approach of using hair-tubes to monitor the European red squirrel: A method applicable at regional and national scales. Mammalian Biology 74: 210-219 (doi:10.1016/j.mambio.2009.02.003).

The ecology of the invasion of the Barbary Ground Squirrel on Fuerteventura Island (Canary Islands)

Background

In 1965, the Barbary Ground Squirrel (Atlantoxerus getulus), a rodent native to Morocco and small areas of Algeria, was introduced onto Fuerteventura Is. Two squirrels were brought in as pets, but they were soon released and the species successfully colonized the island. Some 40 years after the invasion, few data exist on the ecology of the ground squirrel and its impacts on the native flora and fauna. In 2003 I began a PhD which was focused on the ecology of this invasion.

Objectives

The main objectives pursued in this thesis are: 1) to understand why the species was so successful in colonizing the island; 2) to explore some of the impacts that the species might have.

Objective 1

Four factors have been considered to understand the success of the invasion:

• Climate suitability on the island. To explore this we have used predictive climatic models based on presence data of the ground squirrel in its native range and extrapolated the conditions to Fuerteventura Is. and the whole archipelago.
• Habitat availability on the island. I have studied various habitat variables that are associated with the presence of the ground squirrels.
• Presence of predators in the island vs. in the native distribution area. I study the diets of all the potential predators on the island and compared these with data available from the continent.
• Parasite load. I have explored both the ecto- and endoparasites of the species on the island and in Marocco. There are fewer parastites in the island population than in its native range.

Objective 2

Two potential impacts of this rodent have been explored during this project:

• The impacts on predators populations. One species of raptor, the Common Buzzard (Buteo buteo) appears to have been affected by the presence of this new prey.
• The impacts on disruption on the dispersal mechanisms of native fleshy-fruit plant species.

The project is almost finished and many results are under review by different journals.

Study area

This study was mainly done in Fuerteventura Island, Canarian Archipelago. The Canarian Archipelago consists of seven main volcanic islands situated between 27º-29ºN and 13º-18ºW off the Atlantic coast of north-west Africa. Fuerteventura is the second largest island (1660 km2), the second lowest in altitude (807 m a.s.l.), the oldest and is the nearest to the African continent (approximately 100 km distant).

Financial support and collaborators

This work was mainly financed by La Obra Social de La Caja de Canarias and Cabildo de Fuerteventura, as well as by a fellowship to me supported by the Ministerio de Educación y Ciencia.The study was done with the continuous support of Dr. Fernando Hiraldo. Dr. Manuel Nogales, Dr. Jorge Lobo and Dr. Carlos Feliu collaborated partially with it.

For further details, contact Marta López-Darias, Island Ecology and Evolution Research Group, Instituto de Productos Naturales y Agrobiología, IPNA-CSIC, 38206-La Laguna, Tenerife, Canary Islands. Email: ,