Changes in the density and spatial distribution of red fox dens and ...

More documents

Recommendations

Info

Response of red fox to rabies vaccination 1231. Counting of tracks on snowIn winter, indices of fox abundance were obtained fromsnow tracking conducted on transects. The first half ofFebruary, when mating season occurs, was excluded fromtracking. These transects were walked by observers within1–2 days of new falls of snow. The index of fox density usedwas the number of fox trails crossing 1 km of transect perday (n tracks/1 km/24 hrs) calculated as a mean for thewinter season. The yearly mean length of transects in thefirst period (1979–1995) was 90 km and in the second(1996–2006) was 54.6 km.2. Estimation of natal densAt the beginning of spring, an attempt was made to locateall dens present in the study area. Although the locationsof the majority of dens were already known due toearlier investigations, several new dens were found everyyear. Information obtained from hunters, farmers and foresterswas also checked. The identification of natal denswas based on the presence of animal tracks at the entrancesand in close proximity to burrows. Other signs of animalpresence taken into account were: carrion remains and remnantsof prey, faeces of cubs and the typical odour. Thecounts of cubs were performed at natal dens in May andJune. An attempt was made to observe dens for long enoughto count all cubs appearing at the surface. If necessary, observationswere repeated over subsequent days. In case ofabsence of cubs in a den, irrespective of unquestionablesigns of animal presence, neighbor dens were also checkedto register the facts of carriage of young.3.ThebattuemethodIn late autumn (October, November) and early spring(March), driving censuses (aimed at estimating the densityof roe deer and hare populations) were undertaken in localforests by the staff of the Department of Zoology and GameManagement and students of Warsaw Agricultural University.Each forest compartment to be censused was surroundedby observers who stationed themselves 50–100 mapart (to maintain visual contact). The observers alongthree sides of an estimated compartment remained stationary,while those along the fourth side moved inward andwent through the entire area. The observers (both stationaryand moving) noted animals passing through the line ofobservers and the closed area being censused. This methodof animal counting excluded duplication of measurements(Pucek et al. 1975). Apart from hares and roe deer, the foxespresent in an area were also noted.The three methods of fox density assessment presentedhave been used continuously on our study area for the last25 years. Average yearly results were compared betweenthe periods before and after the anti-rabies vaccination programwas implemented.Student’s t-test and test for comparison of two percentages(Bailey 1995) were applied in statistical analyses.Results and discussionThe results obtained with all three studymethods showed a significant increase in the foxpopulation, when the two analysed periods wereTable 1. Changes in density indices of the fox populations before (1980–1995) and after (1996–2005) the onset of the rabiesvaccination program, as calculated by the three different methods (Rogów, central Poland). 1 – Goszczyñski 1989, J. Goszczyñski,unpubl.; 2 – Data from Department of Forest Protection and Ecology, Agricultural University of Warsaw; 3 –Goszczyñski 1989, Lach 1991; 4 – Jackowski 1999, Juszko 2005 and this paper.Mode of estimation and estimated areaParametersCompared periods1980–1995 1996–2005tpSnow trackings – whole terrain Number of seasons analyzed 14 7Total length of snow tracking (km) 1244.70 383.00Mean density (n tracks/km/24 hrs) 5.86 1 11.01 4.85 < 0.001SD 1.78 2.82Driving censuses – forests only Number of seasons analyzed 12 9Total surface of driving censuses (km 2 ) 21.04 29.87Mean density (n inds./km 2 ) 1.22 2 2.58 2 2.86 < 0.05SD 1.08 1.28Number of dens with cubs – whole terrain Number of seasons analyzed 12 7Total number of dens with young 112 105Yearly mean of dens with young 9.33 3 15.00 4 4.41 < 0.001SD 1.70 3.55
Page 1: Acta Theriologica 53 (2): 121-127,
Page 5 and 6: Response of red fox to rabies vacci
Page 7: Response of red fox to rabies vacci

Changes in the density and spatial distribution of red fox dens and ...

Create successful ePaper yourself

Delete template?

Save as template?