aquatic alien mammals introduced into italy: their …• training courses for the volunteers cost...
TRANSCRIPT
Aquatic alien mammals introduced into Italy: their impact and possibility of control
Sandro BertolinoUniversity of Turin, DIVAPRAEntomoloy & Zoology
Genovesi PieroNational Wildlife Institute
Biological Invasion in Inland WatersInternational Workshop – Florence, May 5-7, 2005
Outline
• Aquatic Mammals introduced into Italy
who are they?
where are they?
what are they doing?
what are we doing?
• Control vs eradication: an example from the management of coypu in Italy and England
• An example of strategic approch to coypu control
• General conclusions
Outline
• Aquatic Mammals introduced into Italy
who are they?
where are they?
what are they doing?
what are we doing?
• Control vs eradication: an example from the management of coypu in Italy and England
• An example of strategic approch to coypu control
• General conclusions
Aquatic mammals introduced in Europe
North AmericaMustela visonAmerican mink
South AmericaMyocastor coypusCoypu
North AmericaOndatra zibethicusMuskrat
North AmericaCastor canadensisAmerican beaver
OriginSpecies
American mink Mustela vison
World spread and introduction
Source: J. L. Long, 2003 Introduced mammals of the world
American mink Mustela vison
•Escape from fur farms
•Deliberate releases
Introduction causes Italian distribution
American mink Mustela vison
Presently no damage is reported in Italy, but in other European countries the American mink threatens other species through:
• predation (ground nesting birds, water vole)
• competition (European mink)
American mink Mustela vison
Recent releases from fur farms in Italy
• 5000 animals Parma
• 3000 animals Forlì (2001)
• 5000 Treviso (2002)
• 20.000 Ferrara (2003)
• 200 Padova (2005)
Propagule pressure
American mink Mustela vison
To prevent new establishment it is important to build-up a rapid response system.
Thus the National Wildlife Institute is preparing an action plan,
with the constitution of task-forces at the Regional or Provincial level
in order to capture the animals in few days after their releases.
Prevention
Muskrat Ondatra zibethicus
World spread and introduction
Source: J. L. Long, 2003 Introduced mammals of the world
Muskrat Ondatra zibethicus
Italian distribution
•Escape from fur farms
•Deliberate introductions
Introduction causes
Muskrat spread
The beginning of an invasion: the spread of the muskrat from the point of introduction of five individuals near Prague in 1905 (modified from Ulbrich 1930).
Muskrat Ondatra zibethicus
Presently no damage is reported in Italy, but in other European countries the muskrat
• damage aquatic vegetation,
• undermines river banks and dikes for its burrowing activity,
• there is some evidence of negative impacts on invertebrates through the change in habitat structure
Coypu Myocastor coypus
World spread and introduction
Source: J. L. Long, 2003 Introduced mammals of the world
Coypu Myocastor coypus
•Escape from fur farms
•Deliberate introductions
Introduction causes
Source: Mitchell-Jones et al, 1999 The Atlas of European mammals
Italian distribution
Alien species management
The coypu is considered a pest because of
• the damage produced to crops,
• the damage produced by feeding on aquatic vegetation,
• for its burrowing activity that undermines river banks and dikes,
• a negative impact on birds nesting in the aquatic vegetation and near the rivers has been suggested.
Outline
• Aquatic Mammals introduced into Italy
who are they?
where are they?
what are they doing?
what are we doing?
• Control vs eradication: an example from the management of coypu in Italy and England
• An example of strategic approch to coypu control
• General conclusions
Cost/benefit analysis of two opposite approaches to pest speciesmanagement: permanent control of Myocastor coypus in Italy versuseradication in East Anglia (UK) Panzacchi et al. submitted
• Official eradication started in 1981 (intensive trapping before).
• 24 trappers involved, ensured salary for the entire period; reward for earlier completion of the eradication
• 31,822 coypus killed.
0
2000
4000
6000
8000
10000
12000
14000
16000
1978 1980 1982 1984 1986 1988 1990
• After 1989 no occurrence recorded
Coypu’s eradication in East Anglia(Gosling et al., 1981; Gosling & Baker, 1999)
• 24 trappers, 40-50 traps per person
• 10-15 rafts
• 4-5 boats
• Costs, actualised to yr 2000, about 5 million €
IS IT TOO MUCH?
Coypu’s eradication in East Anglia(Gosling et al., 1981; Gosling & Baker, 1999)
• Introduced in the 1960s
• Range = 68.599 Kmq
• Continuous range in North
and Central Italy
• Still scattered in the South
• Progressive expansion
• Recently introduced in Sicily
and Sardinia
Coypu’s range in Italy
• 297 public institutions contacted sending 2 questionnaires:
• Q1 (focusing on damage to agriculture and coypus control)
was sent to Regional and Provincial Wildlife Departments
and to Park Departments;
• Q2 (focusing on damage to river banks and drainage
channels) was sent to he Drainage Authorities.
… survey on the economic losses
• traps (8 yr amortisation)• kits for euthanasia• anaesthetics• bullets• plastic gloves• freezers (12 yr amortisation)• use of cars or boats• rafts, baits • plastic bags • disposal of carcasses (incinerated
or buried), • staff salary• volunteers reimbursement• training courses for the volunteers
Cost of control including :
… survey on the economic losses
MATERIAL
PERSONNEL
All costs were corrected to year 2000 value, using an economical revaluation coefficient table
€
0
50000
100000
150000
200000
250000
300000
350000
1995 1996 1997 1998 1999 2000
Damage to cropR2 = 0.93, P = 0.002
Co
mp
en
sate
d d
am
ag
e t
o
cro
ps
0
10000
20000
30000
40000
50000
60000
70000
Killed coypusR2 = 0.93, P = 0.002
N. k
ille
d c
oyp
us
Impact on crops and n° killed coypus
Pearson R = 0.92, P = 0.008
0
200.000
400.000
600.000
800.000
1.000.000
1.200.000
1.400.000
1.600.000
1.800.000
1995 1996 1997 1998 1999 2000€
Costs of floods not considered: e.g.: 7th August 1998 Brenta river bank collapsed devastated the community of Loreggia, destroying buildings and fields. Est. losses ca. 16 Mln €.
Damage to riverbanks
R2 = 0.96, p < 0.001
Cost of control
0100.000200.000300.000400.000500.000600.000700.000800.000
1994 1995 1996 1997 1998 1999 2000
R2 = 0.85, p = 0.006
Damage to crops
Costs of control
Damage to riverbanks
TOTAL R2 = 0.87, P = 0.007
Total costs
0500.000
1.000.0001.500.0002.000.0002.500.0003.000.0003.500.0004.000.000
1994 1995 1996 1997 1998 1999 2000 2001
€
€ 3.77 MILLIONS
• Present range = 68,599 Kmq
• Potential expansion (suitable habitat) 330%
• Total costs (yr 2000) = € 3,773,786
• Potential future costs > 12 mln €/yr
Ottaviani, 2003
0
2
4
6
8
10
12
UK eradication Mngmt cost/yrItaly
Predictedmngmt cost/yr
€ Million
Future costs of Coypu management in Italy
1. Widespread perception that costs of eradications
generally outweigh benefits, and that eradications in
most cases fail
2. But! … costs of permanent control largely exceed
costs of eradication
3. Thus, eradication, when feasible, is the best option
in the long term
Conclusions: control vs eradication
1. Competent authorities should eradicate small populations of the American mink and adopt a rapid response system to face new releases
2. and eradicate Muskrat in northeastern Italy, adopting a subsequent control campaign to prevent new arrivals from East
Recommendation for the management of aquatic species
1. Eradicate coypus in isolated and newly colonised areas where it is still technically possible and cost effective (eg. Sicily and Sardinia in Italy, but also Spain).
2. Carefully plan control activities of large populations
3. Always evaluate the efficacy of control operations and adjust future plans accordingly.
4. Concentrate control operation in the most vulnerable areas in terms of biodiversity (protected areas), economically valuable crops (vegetables) and important hydraulic systems.
5. Support research on more effective control methods and prevention strategies
Recommendation for the management of the coypu
Outline
• Aquatic Mammals introduced into Italy
who are they?
where are they?
what are they doing?
what are we doing?
• Control vs eradication: an example from the management of coypu in Italy and England
• An example of strategic approch to coypu control
• General conclusions
A strategic approch to coypu control in small wetland areasBertolino et al. 2005. Wildl. Soc. Bull.
Damage to natural vegetation in thePiedmont Region (Northwestern Italy)
A drastic reduction on aquatic vegetation has been observed
Phragmites australis, Thypa spp., Nymphaea alba, Nupharlutea, Trapa natans
In these protected areas:
• Garzaia di Valenza Natural Reserve
• Restoration area in the Garzaia di Valenza
• Biotope (Natura 2000) Fontana Gigante
• Biotope (Natura 2000) Palude di San Genuario
• Lago di Candia Park
Problem definition
Feasibility
Definition of objectives
Preparing a plan
Implementation of the plan
Monitoring and evaluation
A strategic approach to coypu controlAdapted from Braysher 1993
• In the 90s the coypu colonized an area, the lakes of La Spes, where the Po River Park was re-creatingsome wetlands in previous agricultural areas
Problem definition
• The animals with their foraging activities were stopping the colonization of the aquatic vegetation,limiting the naturalization of the area
The coypu was stopping theevolution of the area toward a
functional ecosystem
Yesterday
Today
Feasibility of control from literature
Trasimeno Lakes
Coypu control: YES
Campotto
Coypu control: NO
Source: Cocchi e Riga 2001
Time
Num
ber
of a
nim
als
Population growth curve of an introduced species
Carrying capacity
1
2
Possibility to control the population
Control not possible
From the literature: if the effort isappropriate and the density not too high, it is possible to control coypu populations with cage-trapsGosling 1990; Cocchi & Riga 2001
Definition of objectives
• Allow the natural vegetation to grow
• Recover the functional ecology of the area
• Prepare an action plan for the control of the coypu in other wetlands managed by the park
Trapping in 2 areas
• A closed area
surrounded by crop fields and poplar plantations, with a probable low degree of colonization by coypu dispersing from other areas
• An open area
a canal flowing into the River Po. Here coypus were part of alarger population distributed along the River Po
Feasibility: an experimental approach
0
4
8
12
0 1 2 3 4 5 6 7
Weeks of capture
Coy
pus r
emov
ed
048
1216
0 1 2 3 4 5 6 7 8
Weeks of capture
Coy
pus r
emov
ed
Closed area
Open area
Control results 1998
R2 = 0.89; P = 0.004
Difference between seasons Closed P<0.01
Open N.S.
3
11
2
13
25
1916 17
0
5
10
15
20
25
30
Winter Spring Summer Autumn
Co
ypu
s re
mo
ved
Closed area Open area
Control results 1999
• Control in 2 periods: winter and autumn
• Use of 5-10 cage-traps per area
• 1 person working
• Traps activated for 2-3 days a week
• For a period of 5-7 weeks
Implementation of the plan: Methods
Continuing the control started in 1998 in therestoration area (closed area)
In 2000 starting the control in the EU Biotope(Natura 2000) Fontana Gigante
In 2001 starting the control in the EU Biotope(Natura 2000) Palude di S. Genuario
Implementation of the plan: Areas
Fontana Gigante
Palude di S. Genuario
Monitoring and evaluation: results
05
101520253035404550
Win. Aut. Win. Aut. Win. Aut.
2001 2002 2003
Period
Ani
mal
s re
mov
ed
Valenza Fontana Gigante S. Genuario
Coypus removed in the 3 areas during the period: 2001-2003
0
5
10
15
20
25
30
Den
sity
(coy
pus/
ha)
Removal densities of coypu in the 3 areas and different periods (1998–2003, light blue dots) and density of coypu populations from other areas (red dots)
Red dots data from: Norris 1967, Brown 1975, Willner et al. 1979, Doncaster and Micol 1990, Velatta and Ragni 1991, Reggiani et al. 1993).
Monitoring and evaluation: results
Carrying capacity
1
2Other areas
Wetlands in the park
Coypu populations were limited by the controleffort in the 3 areas
… but this is not enough !
Thus did we meet all the objectives of the control plan?
Monitoring and evaluation: coypu populations
We were interested in the recoveryof natural vegetation !
Surface covered by yellow waterlilies in 3 ponds, before coypus colonization, during coypu feeding, and after coypu removal
01.0002.0003.0004.0005.0006.0007.0008.0009.000
Beforecolonization
Coypu feeding After control
Sur
face
(sq
m)
Pond 1 Pond 2 Pond 3
Monitoring and evaluation: natural vegetation
In small areas it is possible to control coypu inorder to let the natural vegetation to recover
Conclusion
When control campaign are planned it is important to evaluate the efficacy of the controloperations and adjust future plans accordingly
Outline
• Aquatic Mammals introduced into Italy
who are they?
where are they?
what are they doing?
what are we doing?
• Control vs eradication: an example from the management of coypu in Italy and England
• An example of strategic approch to coypu control
• General conclusions
General conclusion I
Prevention is a better strategy than eradicationor control !!
Every alien species needs to be managed as potentially invasive, until convincing evidence indicates that it is not threatening,
avoiding its release in the wild and maybe limiting the importation in the country
Considering the risks posed to biodiversity and human activities, Italy must adopt a precautonary principle, removing small nuclei of introduced species before they spread in large area.
Accordingly to the European strategy, Italy is called to build-up a rapid response system in order to avoid further releases of alien mammals in the wild.
General conclusion II
Thank you for your attention !!