DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu
| ŠUMARSKI LIST 9-10/2010 str. 51 <-- 51 --> PDF |
M. Čas: DISTURBANCESAND PREDATIONAT CAPERCAILLIE LEK HABITATS INALPS ... Šumarski list br. 9–10, CXXXIV (2010), 487-495 RESEARCH RESULTS – Rezultati istraživanja 3.1. Leks destruction – causes and dynamics – Uništenje pjevališta i dinamika In years 1979-1981 39 (or 8.4%) out of 466 analysed lek habitats experienced disturbance or destruction. As the main reasons of capercaillie lek habitat destruction in this monitoring period were: cutting of old- growth forests (71.8% of disturbed or destructed leks), building of forest roads (7.7%), overgrowing of pastures in mountain forest areas (7.7%), berry picking (5.1%), human disturbances of mountain tourism (recreation, motor vehicles) (5.1%) and predators (fox, martens, wild boar, lynx, etc.) (2.6%) (Table 1). In the monitoring period 2000 92 leks were disturbed or destructed (15,4% out of 599 monitored). Main reasons for a lek disturbance or destruction were; different forms of mountain tourism (26.1% of disturbed or destructed leks), cutting of old-growth forests (19.6%), predation at lek habitats (18.5%),forest management in spring matting time (9.8%), pasturage of cattle and sheep in forests (namely the dangerous are wire fences) (6.5%), overgrowing of pastures in mountain forests (5.4%), berry picking (5.4%), construction of forest roads (4.3%), and infrastructure building activities (electricity cords) (1.1%) (Table 1). The comparison of both monitoring periods (Table 1) revealed differences in lek disturbance or destruction causes which were correlated with the following improvements: a decrease in the cutting of old-growth forests at leks (-52.2%), and a minimum decline of impact of forest roads construction (-3.3%).The deterioration in habitats showed an increase in the negative impact of mountain tourism (with 21% increase among years) and increase of the negative predator impact (15.9%). Other lek disturbance or destruction causes showed lower increase among the two monitoring periods. Table 1 The most frequent causes of capercaillie lek disturbance or destruction as revealed from 1980 and 2000 monitoring periods questionnaires Tablica 1.Najučestaliji razlogi za poremečaj ili uništavanje staništa tetrijeba u godinama 1980 – 2000, dobivenih na osnovu upitnika Impacts at leks’habitats Number of disturbed or damaged leks in 1980 monitoring Percentage within disturbed or disturbed leks (%) in years 1980 Number of disturbed or disturbed leks in 2000 monitoring Percentage within disturbed or disturbed leks (%) in years 2000 Difference among two monitoring periods, expressed as a % of change in regard to 1980 monitoring period Cutting of old-growth forests 28 71.8 18 19.6 -52.2 Construction of forest roads 3 7.7 4 4.3 -3.3 Infrastructure (electricity) 0 0.0 1 1.1 +1.1 Forest management in spring time 0 0.0 9 9.8 +9.8 Mountain tourism (recreation, motor vehicles, etc.) 2 5.1 24 26.1 +21.0 Predators (fox, martens, wild boar, lynx, raptors, etc.) 1 2.6 17 18.5 +15.9 Berries picking 3 7.7 5 5.4 -2.3 Pasturage of livestock in forests, wire fences 0 0.0 6 6.5 +6.5 Overgrowing of pastures in mountain forests 2 5.1 5 5.4 +0.3 Overall number of disturbed or destructed observation leks 39 92 3. Lek predators and predation level – Predatori na pjevalištima i razina predatorstva Acomparison of the increasing percentage of leks 2.5 animals/1000 ha and for wild boar from 0.8 to 2.0. endangered by predators and trends in density of hunted The hunting dynamics of red fox showed a slight depredator animals in Slovenia showed a positive correla-crease for 18% in the same period.The population dynation with capercaillie leks disturbance and destruction in mics of red fox is suggested to be under a cyclical 20-year time among the two monitoring periods (Table population changes trends causing an increase of popu2). Trends of population dynamics of all three main pre-lation and changes in hunting (to 3.5 hunted anidator species were positively correlated with lek preda-mals/1000 ha) and a negative impact on the capercaillie tion. Density of hunted martens increased from 1.0 to leks vitality was expected to start only after year1990. |