Are pine martens the answer to grey squirrel control? Journalists - - PowerPoint PPT Presentation

Are pine martens the answer to grey squirrel control?

Journalists seem to think so…..

The Vincent Wildlife Trust

• Founded in 1975 by Hon. Vincent Weir
• A charity engaged in mammal research,

surveys, monitoring & conservation

• History of national distribution surveys

– otter, water vole, polecat & pine marten

• Current focus on rare bats and the

smaller mustelids- polecat, stoat, weasel and pine marten.

Research Education Conservation

The pine marten

• One of six native British mustelids
• Cat-sized, cream bib, bushy tail,

prominent pale ears

• 3-D habitat specialist
• Typically associated with extensive

woodland & ‘old growth’ features

• Prefer to den above ground (tree

cavities)

• Home range size 1 - 32km2
• Omnivorous & opportunistic diet –

small mammals, fruit, small birds & invertebrates.

The grey squirrel

• Non-native.
• Introduced to Britain & Ireland.
• Threatens survival of native red

squirrels through competition & disease (squirrel pox virus).

• Cost of grey squirrel damage to

commercial forestry in UK = >£10 million per year.

• “One of the world’s most invasive alien

species” (Lowe et al. 2004).

• Natural range of grey squirrel in North

America overlaps with American marten and fisher (natural predators)

• nly in very small area (Sheehy & Lawton,

2014).

Pine martens and squirrels in Ireland

• Grey squirrels introduced to Ireland in

1911.

• Grey squirrels present in 26 of 32

counties (Carey et al. 2007).

• In late 1990s, red & grey squirrel

populations in some northern counties reported as ‘‘unsettled’’ for first time

(O’Teangana et al. 2000).

• Anecdotal reports that grey squirrel

had declined locally since the 1980s, allowing for a resurgence of the red squirrel population.

• This coincided with recovery of the

pine marten.

• Suggestion that the distribution of the

3 species may be linked (Carey et al. 2007).

The majority of respondents (84.7%) wish to see the Pine marten restored in Wales

• Study carried out in 2011-2012 by

Emma Sheehy & Colin Lawton at National University of Ireland.

• Investigated the role of the pine

marten in grey and red squirrel population dynamics.

Pine martens and squirrels in Ireland

Methods: Study area: Laois & Offaly (in the midlands) including a buffer zone, & Wicklow (in east).

• Sightings and hair tube

surveys used to collect distribution data on pine martens & squirrels.

• Squirrels live trapped to

determine abundance and density.

• Squirrel body size,

condition & breeding activity recorded.

Research Education Conservation

Pine martens and squirrels in Ireland

Sheehy & Lawton, 2014

Research Education Conservation

Results:

• Strong negative correlation between detection of grey squirrel

& pine marten. Only 1 site where both species were found.

• Grey squirrel population has crashed in 9,000 km2 of its former

range.

• Red squirrel has recolonised 6,500 km2 of its historic range.
• Red squirrel & pine marten populations overlap extensively but

grey squirrel & pine marten overlap is limited.

• In woodland where pine martens occurred at high density, grey

squirrel density was very low & grey squirrel body mass was low & overall health was poor.

• High density predator population may be influencing foraging

behaviour, body condition, reproductive activity or density in grey squirrel population.

Pine martens and squirrels in Ireland

Sheehy & Lawton, 2014

Research Education Conservation

Grey squirrel & pine marten distribution & densities from sightings between 2010-2012. Sighting locations (left) & 10km radius kernel density (right).

Pine martens and squirrels in Ireland

Sheehy & Lawton, 2014

Pine martens and squirrels in Ireland

Pine marten diet

• Grey squirrel % frequency of
• ccurrence in diet = 15.6%.

Similar to contribution of grey squirrel to American marten & fisher diet in North America.

• Red squirrel % frequency of
• ccurrence in diet = 2.4%.

Consistent with other studies in Ireland & Scotland.

Sheehy et al. 2013

Pine martens and squirrels in Scotland

• Anecdotal evidence that where pine

martens have recovered & expanded their range in parts of Scotland, grey squirrels have declined.

• Research underway by Emma Sheehy &

Xavier Lambin at Aberdeen University to investigate relationship between pine martens, grey & red squirrels in Scotland.

Pine Marten Recovery Project

• Aims to restore viable, self-sustaining

pine marten populations across England and Wales where habitat &

• ther conditions are suitable.
• First translocations taking place now:

20 animals being translocated from Scotland to mid Wales, to reinforce small existing population.

• Feasibility study completed in 2014
• Evaluated proposal against IUCN

guidelines

• Used habitat suitability model to identify

suitable release sites

• Community/stakeholder engagement in

potential release areas

• Identify potential conflicts
• Detailed field surveys & risk assessments
• Disease Risk Analysis completed by

wildlife vet & reviewed by veterinary experts

Feasibility Study

• Habitat suitability model

(MAXENT) identified areas

• f suitable habitat for pine

marten reinforcement (most

suitable areas in green on map).

• Optimal areas will have:
• Minimum habitat area and

connectivity for viable numbers

• f pine marten home ranges.
• Minimum potential conflict

& full support of local communities.

Identifying reinforcement areas

Initial release sites in mid- Wales.

Identifying reinforcement areas

• Gathered baseline data on:
• Prey availability (small

mammal surveys)

• grey squirrel abundance
• bat species
• woodland structure &

composition

• Prepared release sites
• Release pens
• Den boxes

Preparing release sites

• Liaising with landowners/users.
• Meetings with NFU/FUW.
• 3 public community meetings.
• Attendance of local shows (e.g. Welsh

Game Fair).

• Highlighting local history & heritage –

Bele’r coed.

• Public opinion survey showed >90%

respondents supportive of pine marten recovery.

Engaging people

• Surveys at ‘donor sites’ in Scotland.
• Licence granted by Scottish Natural

Heritage to remove pine martens.

• Catching 2-4 adults from each site

(equal ratio of males & female). Full health check & fitted with radio- collars before translocation.

• NRW licences granted to release,

and Home Office licences to catch, process & tag animals

Sourcing animals

Why help pine martens recover?

• Native species - it should be here!
• No evidence of natural recovery in

Wales & England

• Intrinsic value, biodiversity, iconic

woodland species

• Potential for eco-tourism
• Biological control for grey squirrels?

(Interest in ‘ecosystem services’)

• Feasibility study cost £100k
• Reinforcement program total >£1m

Pine Marten Recovery Project

Pine martens and squirrels in Wales

As part of pine marten release, a PhD student is researching direct & indirect influences of pine martens on grey squirrels before, during & after translocation. Research includes:

• Pine marten foraging & the extent of

predation of squirrels

• Squirrel population studies
• Radio-tracking of squirrels to investigate

behavioural change.

• Assessing any reduction in tree damage by

grey squirrels over time.

So, are pine martens the answer to grey squirrel control?? Maybe….but that’s not why we’re conserving them!

www.vwt.org.uk www.pine-marten-recovery-project.org.uk