wise use of mires and peatlands - Peatland Ecology Research Group

62 VALUES AND FUCTIONS OF MIRES AND PEATLANDSVascular plant species 10 3 kg year -1Menyanthes trifoliata, Polygonum bistorta, Arnica montana 10 - 100Acorus calamus, Althea officinalis, Frangula alnus, Nuphar lutea,Ledum palustre, Valeriana officinalis 100 - 1000Vaccinium myrtillus, Vaccinium vitis-idaea 1000 - 10000Table 3/10: Order of magnitude of annually collected mire plant material for medicine in theformer USSR (in 10 3 kg year -1 ) 103 .natural peatlands in Finland increased from100 kg to 2100 kg 106 .In Canada Labrador Tea (Ledumgroenlandicum) is used as a medicinal plant.In countries where there has been destructionof mires the extent of local collection of mireplants for medical purposes has decreased.This leads to increased imports of mire plantproducts from countries where large areas ofmires remain, which increases the pressureon the resources in those countries.(d) Wild animals for food, fur andmedicine 107Many fur-bearers such as coyote, racoon,mink and lynx and game species such asgrouse, ducks, geese and moose are oftenfound in peatlands. In North America, blackbears, which are used for food and fur, aswell as in traditional medicine (bladders), arealso frequently found in peatlands. Whilethese species do not depend on peatlandsfor their survival this habitat may contributesubstantially to their continued presence inpopulated regions where few areas other thanpeatlands provide safe havens away fromdirect human disturbance.Peatlands may also be significant for fisheries.In tropical peatlands, fish provide importantproteins to local communities 108 . Manycoastal tropical fish are highly dependent onmangroves for nursery, feeding, andspawning grounds.(e) Peat substrates in situSome carrier functions (forestry, agriculture,horticulture) have been included underproduction functions because in their case itis difficult to separate the production andcarrier functions.(ea) Agriculture and horticulture in situ 109The capacity of peatlands for agriculturalproduction depends on a number of naturaland socio-economic factors. The naturalfactors include■ climatic conditions,■ the landscape position of the peatland,■ the type of peat deposit,■ the water and oxygen content of the soil,■ the physico-chemical properties of the soil,■ vegetation.Climate: Climatic conditions impose thebasic limitations on peatland agriculture.Cultivated plants require an adequately longvegetation period and a minimum amount ofheat energy. Consequently the temperatureconditions that are determined by themacroclimate of the region and modified bythe microclimate of the peatland are decisive.The following factors make cultivationdifficult or impossible:– too short a growing period,– a mean annual temperature which is too low,– excessive variation between the meantemperatures of the warmest month (July)and the coldest month (January),– excessive variations in temperaturebetween day and night,