Reindeer in Iceland An Introduced Population in an Exploited Ecosystem Rán Þórarinsdóttir & Skarphéðinn G. Þórisson
Overview Preface History • The introduction • Habitat quality • Reindeer condition • Management
Overview Adapting to changes • Carrying capacity –Changes in distribution
• Human activities • Climate changes Conclusions
Introduction • Tame Norwegian reindeer ( Finnmark) were introduced in Iceland four times in the late 18 century (successful in 1787) • These originally semi domesticated animals have lived wild in Iceland from day one • They've had more than 200 years to adapt to Icelandic surroundings and settled in the east • They seem well adapted; but are they really and has Iceland adapted to the reindeer?
THE INTRODUCTION
The Introduction • The first winters in Iceland in unfamiliar territory and different environmental conditions put the imported reindeer to the test • Singular hard winters were a serious threat while the population size and distribution was limited SGÞ
The Introduction • Genetic homogeneity could have led to extinction early on as the imported animals were few • Founder population <15 animals (Röed et al.1985)
SGÞ
The Introduction • The population has seen declines • In the last 70 years ‐> more or less an upward trend slowed down foremost by hunting. 6000 5000 4000 3000 2000 1000 0
1940
1950
1960
1970
1980
1990
2000
2010
Habitat Quality
• No large herbivores existed in Iceland before the settlers brought livestock in the 9th and 10th century, • Icelandic farmers have never been very numerous and the land is spacious. SGÞ • But...
Habitat Quality • Defense mechanisms against grazing, may be underdeveloped in plants that grow in surroundings with little grazing pressure • ‐>Icelandic vegetation was/is sensitive to grazing
Habitat Quality • Because of the sparse vegetation, short summers and slow regeneration, it can be debated, that when it comes to grazing of large herbivores, the land is fully occupied SGÞ
Habitat Quality • Because of volcanic activity, glaziers, harsh weather and grazing of livestock, erosion is a serious problem • A study showed high, possibly toxic levels of iron in reindeer foodstuff
Habitat Quality • The cause is acid insoluble ash, which adhere to vegetation Chase et al 1994
Habitat Quality Reindeer distribution
Habitat Quality Reindeer habitat divided into hunting areas
6000 5000
Km2
4000 3000
Vegetation
2000
Deserts/Peaks
1000 0 1
2
3‐5
6
7
8‐9
6000 5000 Km2
4000
Lush vegetation
3000
Sparce vegetation
2000
Meager vegetation
1000 0 1
2
3‐5
6
7
8‐9
Habitat Quality • Even with regular traffic to the country and import of species, the island is far from the mainland and species diversity is low
SGÞ
Habitat Quality • Isolation still keeps at bay many threats that cause trouble for continental species – There are no large land predators (the arctic fox is the largest!) – Insects, parasites and diseases are few and of little consequence to the population – ...so far
Condition • Mortality: Harsh winters with widespread non‐penetrable ice crust and lack of available food source have been the main reason for high 'natural' mortality in singular years
SGÞ
Condition • Such conditions are rare in later years and in the last 50 years there has hardly been any natural constraints on the population growth • The animals are generally in good body condition and fertility is high (80‐90%).
SGÞ
Condition • Isolated and protected surroundings together with low genetic homogeneity makes reindeer vulnerable to future ecological changes
SGÞ
Management â&#x20AC;˘ Reindeers in Iceland were hunted for meat and in the beginning the hunting was controlled to prevent overhunting â&#x20AC;˘ But as Icelandic farmers have always used available pastures for livestock, and later on for forestry or construction projects, it soon became imminent to keep reindeer densities at low levels â&#x20AC;˘ Since 1940 the population size has been controlled through hunting
Management • In the 1940s the country was divided into sheep quarantined areas, as part of an eradication campaign against sheep diseases (lentiviral diseases, M. paratuberculosis and e. scrapie) Guðmundur Georgsson et al 2006
SGÞ
Management • Management objectives have, from early on, also been to keep the reindeer population from distributing into disease free areas
SGÞ
Management â&#x20AC;˘ In the last twenty years there has been a reduction in livestock utilizing the same pastures as the reindeer
SGĂ&#x17E;
Management â&#x20AC;˘ Less grazing pressure together with a milder climate has boosted vegetation â&#x20AC;˘ Reindeer hunting is today a popular sport and the demand for higher harvest is becoming more strident SGĂ&#x17E;
Management â&#x20AC;˘ At the same time anthropogenic pressures is changing, forestry and construction projects are more common and reindeer do not always fit into those plans
SGĂ&#x17E;
Management • Monitoring organizations are needing better arguments to defend present reindeer numbers
SGÞ
ADAPTING TO CHANGES
Carrying Capacity • Definition: The maximum population size of a species that the environment can sustain …indefinitely
Carrying Capacity • An ever changing and unknown magnitude • Highland pastures are sensitive to grazing ‐> carrying capacity is low
SGÞ
Carrying Capacity • Indications of overgrazing: – A study made in 1979‐1981 on reindeer highland pastures (Fljótsdalsheiði) ‐> few lichens left in large areas – Another example from the east fjords (Norðfjörður): Numbers doubled from 300 in 1975 to 600 in 1985 ‐> Signs of over grazing
Carrying Capacity • Modern management tries to keep densities at low levels but no formal threshold exists
SGÞ
Carrying Capacity â&#x20AC;˘ A study from sensitive lichen rich winter pastures in Scandinavia: More than 2 reindeer/km2 might lead to collapse in the population Helle et.al. 1990
Carrying Capacity • Other references give similar or higher thresholds • Less than 1 reindeer/km2 should be moderate densities • But reindeer are not the only grazers in the east…
Estimated grazing pressure in reindeer habitat 2012 Population Species Grazing days size Geese and swans 12.580 175 Rock ptarmigan 100.000 365 Reindeer 5.000 365 Sheep 207.382 120 Geese and swans Rock ptarmigan Reindeer Sheep
Food intake (tonnes)/year 1.844 2.190 4.791 52.260
Density per km2 of vegetated area in reindeer pastures Summer Species Population Sheep 207.318 Reindeer 6.000
SGÞ
Density Area (km2) (animals/km2) 9.103 22,77 9.103 0,66
SGÞ
Carrying Capacity • So far so good but… • Reindeer are flexible animals • They move around and are not evenly distributed • What happens if they move all to one spot?
Density and distribution in 2012 Winter Area Density Area Population km2 animals/km2 1 2 3‐5 6 7 8‐9 Total
750 400 800 700 1500 650 4800
2532 2822 1427 762 676 884 9103
0,3 0,14 0,56 0,92 2,22 0,74 0,53
Carrying Capacity • How long can they stay in such densities before we have to intervene? • The fjord area is mountainous and population counts are more difficult‐>not done annually • Hunting location points gave us an idée on how the distribution changed
Changes in Distribution Hunting locations : 2009 something was changing 2010 2011 2013?
Changes in Distribution • With the help of GPS collared females we can have a closer look at habitat use for 2009 (LBHÍ &LV) • One of six females showed unexpected route behavior
Changes in Distribution • March‐September 2009 • She changes route sometime in early august • Probably together with other herds
Changes in Distribution • Changes in distribution implies changes in habitat quality
Carcass weight
Fjords
2012…
2011…
2010…
2009…
2008…
2007…
2006…
2005…
2004…
2003…
2002…
Highland
2001…
47 45 43 41 39 37
2000…
Female weight (kg)
• Female carcass weight is higher in the fjords • Weight has been going down for some time • Did highland cows reach a threshold in 2008?
Calves per 100 females and yearlings
• Calve survival has also had a downward trend • Weather related? 65
2
60
0
55
‐2
50 45
‐4 Ísland
40 35 30
Hardangervidda North Atlantic Oscillation 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
‐6 ‐8 ‐10
NAO annual index
Calve survival
Changes in Distribution • Are changes in distribution common and maybe a natural way of distributin grazing pressure?
Changes in Distribution 3500 Jökuldalsheiði 3000
Population size
2500 2000 1500 1000 500 0
V Jöklu
Fljótsdalsheiði
Vesturöræfi
Undir Fellum
Múli
Changes in Distribution 3500
Jökuldalsheiði Óskipt V Jöklu Fljótsdalsheiði Vesturöræfi Undir Fellum
3000
2000 1500 1000 500
2011
2009
2007
2005
2003
2001
1999
1997
1995
1993
1991
1989
1987
1985
1983
1981
1979
1977
1975
1973
1971
1969
1967
0 1965
Fjöldi hreindýra
2500
Human activities • Roads and industrial projects have already fragmented the reindeer habitat somewhat with potential cumulative effects that have yet to be revealed
Human activities • A dam construction in Háls valley, a known calving area of the Snæfell's herd started in 2003 • A large reservoir was formed in 2007
SGÞ
Human activities â&#x20AC;˘ Singular counts before 2005 showed that many hundred cows calved regularly in the area, in and around this valley
Human activities • From 2005 cows are fewer in the highland, distributed over a larger area and distribution changes between years
Human activities
2006
2008
Human activities • Why is the distribution varying between years? • • •
•
Normal variation? Reaction to higher densities in the calving area? Changes in weather with subsequent changes in e.g. snow cover and vegetation? Disturbance caused by human activities?
Climate change • Climate changes with alteration in vegetation, food availability and pathogen threats are likely to affect the population in future • Less snow may lead to more exposed vegetation cover and faster withering during summer • New pathogen species or higher abundance of existing species can also seriously affect reindeer condition
Climate change • Already we are seeing changes in weather with fewer difficult winters and less snow cover
SGÞ
Climate change • So far this has not affected the animals visibly • The longtime effects of ecological changes have yet to be revealed • Protected surroundings together with low genetic homogeneity in the Icelandic reindeer gives us sufficient reason to worry
Takk fyrir
REFERENCES • • •
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Gudmundsdottir, B 2006. Parasites of reindeer (Rangifer tarandus) in Iceland. MSc thesis. In Icelandic with English summary. Thórisson, S. 1984. The history of reindeer in Iceland and reindeer study 1979‐1981. Rangifer 4 (2): 22‐38. Carma (no date). [webpage]. Accessible on the link: http://carmanetwork.com/pages/viewpage.action?pageId=1114390 [last viewed 26. November 2010]. Chase, L. A. Studier, E. H. & Thorisson, S. 1994. Aspects of nitrogen and mineral nutrition in Iceland reindeer, Rangifer tarandus. Comp. Biochem. Physiol. 1:63‐73. Knuth H. Røed, Aud Vold Soldal and Skarphédinn Thórisson 1985. Transferrin variability and founder effect in Iceland reindeer, Rangifer tarandus L. Hereditas 103:161‐164