HUNTING AND FORESTRY DETERMINANTS OF MOOSE POPULATION DYNAMICS Fig. Kaarlo Nygrén Tuire Nygrén Game and Fisheries Research Institute Indian Forest Service mid-career training - Group II Joensuu 28.6.2010
Development of the Finnish moose population in time and space Biology and policies of the moose management Finland
Time BEFORE and AFTER 1969-1971
Before the 1970 s Since the prehistoric times moose have been hunted in Finland, but the population numbers most probably have always been small. As a catch moose was highly valued. Hunting was difficult before the time of firearms but the moose meat made the hunting important for the survival of families and whole villages. The productivity of moose populations were lower than nowadays. The quality and amount of moose feed was up to the 1950 s much lower than nowadays
Nygrén, T. 1987
Nygrén, T. 1987
Why the increase? 1) The area of young forests increased quickly after the war the amount and quality of moose feed was better than ever.
Why the increase? 1) The area of young forests increased quickly after the war the amount and quality of moose feed was better than ever. 2) Big predators (bear and wolf) were absent. Up to the 20th century only near the Russian border small populations existed.
Why the increase? 1) The area of young forests increased quickly after the war the amount and quality of moose feed was better than ever. 2) Big predators (bear and wolf) were absent up to the 20th century only near the Russian border small populations existed. 3) Poaching, sicknesses and other causes of death had a minor role (2-3 % of all deaths) in the population development.
Why the increase? 1) The area of young forests increased quickly after the war the amount and quality of moose feed was better than ever. 2) Big predators (bear and wolf) were absent up to the 20th century only near the Russian border small populations existed. 3) Poaching had a minor role in the population development. 4) The amount of 0,5 year old calves in the bag increased and as a result increased also the average age and the productivity of the population.
Why the increase? 1) The area of young forests increased quickly after the war the amount and quality of moose feed was better than ever. 2) Big predators (bear and wolf) were absent up to the 20th century only near the Russian border small populations existed. 3) Poaching had a minor role in the population development. 4) The amount of 0,5 year old calves in the bag increased and as a result increased also the average age and the productivity of the population. 5) The hunted numbers were smaller than the annual reproduction.
Two main determinants of the moose population development in Finland 1) Forestry - responsible for the amount and quality of suitable food 2) Hunting responsible for the density and structure of the population
When density is not a limiting factor, population structure is decisive for the productivity of the population age structure adult sex ratio
Determination of age structure Fig: Tuire Nygrén
keskimääräinen ikä (v.) Average age of killed moose 5,5 5,0 4,5 4,0 3,5 3,0 urokset (Matson s Lab) naaraat (Matson s Lab) urokset (RKTL) naaraat (RKTL) 1976 1980 1984 1988 1992 1996 2000 Nygrén, T. 2009
Vasojen saalisosuudet (%) Proportion of calves in the bag 70 60 Rannikko-Suomi Sisä-Suomi Oulun lääni Lappi 50 40 30 20 10 0 1960 1970 1980 1990 2000 2010 Nygrén, T. 2009
Pregnancies of Finnish moose females in 1980 Number of feti/100 females alkioita/100 naarasta 180 140 yksi alkio kaksi alkiota 100 60 20 1,5 2,5 3,5 4,5 5,5 6,5 7,5 8,5 9,5 10,5+ naaraan ikä (v.) Age (years) Nygrén, T. 1983
Fig. Tuire Nygrén Dead born sextuplets of Valtimo
vasoja/100 aikuista Number of calves/100 adults 70 60 50 40 30 Rannikko-Suomi Sisä-Suomi Oulun lääni Lappi 20 1970 1975 1980 1985 1990 1995 2000 2005 2010 Nygrén, T. 2009
Fig. V. Minaev Sex ratio
Not just age structure but also the sex ratio changed when main part of the killed moose were bulls and calfs. In Finland all calf rearing cows are protected from hunting. Hunters are also reluctant to kill cows. Drawing: Maija Wallén
lehmiä/sonni Development of adult sex ratio number of cows/one bull 2,4 2,0 Rannikko-Suomi Sisä-Suomi Oulun lääni Lappi 1,6 1,2 0,8 1970 1975 1980 1985 1990 1995 2000 2005 2010 Nygrén, T. 2009
Unequal sex ratio Small choice of bulls Bulls younger than cows Fetilizations from second or third heat Deliveries later than optimal Calves too small to survive the hard winter Risk to the effective size and biodiversity of populations
Kaksos-% 100 80 Twinning-% 1973-2009 Eteläinen sisämaa Eteläinen rannikko Pohjoinen sisämaa Pohjoinen rannikko 60 40 20 POHJANMAA 1970 1975 1980 1985 1990 1995 2000 2005 2010 Nygrén, T. 2009
kaksos-% kaksos-% Correlation between adult sex ratio and twinning -% 1975-2007 50 50 40 40 30 30 20 RANNIKKO-SUOMI y = 64,33-12,07x r = -0,639 P < 0,0001 20 SISÄ-SUOMI y = 62,65-10,41x r = -0,592 P < 0,0001 1,0 1,2 1,4 1,6 1,8 2,0 2,2 lehmiä/sonni 1,0 1,2 1,4 1,6 1,8 2,0 2,2 lehmiä/sonni 50 50 40 40 30 30 OULUN LÄÄNI LAPPI 20 y = 63,44-19,45x r = -0,667 P < 0,0001 20 y = 40,84-9,49x r = -0,190 P = 0,289 1,0 1,2 1,4 1,6 1,8 2,0 2,2 lehmiä/sonni 1,0 1,2 1,4 1,6 1,8 2,0 2,2 lehmiä/sonni Nygrén, T. 2009
Density development Density goals
Nygrén, T. 1987
0,4-0,5 1976-1979 4 2 1980-1983 1-2 3-4 1984-1987 2 3 1988-1993 3,0-4,0 1,2-1,8 2,3-3,0 2,5-3,5 7 4-5 4 1-2 0,5-3,0 0,5-3,0 Moose density goals from 1976 to 2010 1994 2-4 2-5 1995-2003 2004-2-4 2-4 2-4 2-4 2-3 2,0-5,0 2,0-4,0 2-5 2-5 2-5 2-5 2-5 2-4 2-4 Nygrén, T. 2009
hirviä/1000 ha Winter densities (number of moose/1000 ha) 1973-1994 8 7 6 5 4 3 2 1 0 74 76 78 80 82 84 86 88 90 92 94 Rannikko Suomi Sisä- Suomi Oulu Lappi T. Nygrén 1996
1977-78 1979-80 1981-82 1983-84 1985-86 1987-88 1989-90 1991-92 1993-94 1995-96 Hirviä/1000 ha -1.0 Fig 16 1,1-2,0 2,1-4,0 4,1-6,0 6,1-8,0 8,1- T. Nygrén 1996
talvikannassa hirviä/1000 ha Moose density development 1976-2007 black = annual estimations white = retrospective calculations) 8 6 7 RANNIKKO-SUOMI 5 SISÄ-SUOMI 6 5 4 3 2 1 0 vuosittain laadittu kanta-arvio takautuva laskennallinen arvio vuodelta 2007 1976 1980 1984 1988 1992 1996 2000 2004 4 3 2 1 0 vuosittain laadittu kanta-arvio takautuva laskennallinen arvio vuodelta 2007 1976 1980 1984 1988 1992 1996 2000 2004 Nygrén, T. 2009
kaadettu hirviä Licenses and kills 90 000 80 000 kaatolupien määrä kaadettujen määrä 70 000 60 000 50 000 40 000 30 000 20 000 10 000 0 1950 1960 1970 1980 1990 2000 Nygrén, T. 2009
kaadettu/1000 ha Number of kills/1000 ha 5 4 Rannikko-Suomi Sisä-Suomi Oulun lääni Lappi 3 2 1 0 1960 1970 1980 1990 2000 2010 Nygrén, T. 2009
According to the latest results: Only in the northernmost Finland moose densities are higher than the density goals Moose population is more productive than ever before Productivity of the Finnish moose population is highest in the whole world The proportion of adult bulls in the population are lower than ever before
BUT The management and regulation of moose population is difficult difficult to predict population development difficult to estimate effects of mobility difficulties to cope with local variability The amounts of traffic accidents and forest damage are intolerable Moose population has estimated to be an economical burden to the Finnish state Hunters and the rest of the society are on opposite sides of the barricade Moose has lost a great deal of its value as a game animal The moose population has experienced changes, that might be irreversible
Antler types Palmated (A 1 A 1 ) Cervina (A 2 A 2 ) Intermediate (A 1 A 2 ) Figs: Kaarlo Nygrén
Frequencies of the palmated allele Nygrén, T. 2009
Change in frequencies of palmated alleles from 1976-1985 to 1997-1999 1,00 (difference in region III is not statistically significant) 0,75 1976-85 1997-99 0,50 0,25 0,00 Region I Region II Region III Region IV Nygrén, T. 2009
Summary Hunting and forestry have been the most important determinants of the moose population development in Finland. Since 1970 s the biological knowledge of moose has increased a lot but the role of biological knowledge in the decision making is minor at the moment. Both biological knowledge and political organization for decision making are utmost important for the success of the population management. It has been estimated that the moose problems in Finland are a result of a poor governance system that cannot take notice to the complex and unexpected interdependencies between interest groups (Härkönen & Hiedanpää 2007).
Kuva: Minaev