Rabbit control in the Parwan Valley and its value for catchment

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List of TablesTable 1. Some characteristics of the Parwan subcatchments............................................................ 7Table 2. Application rates of poisoned carrots on sites of rabbit activity ........................................ 8Table 3. Mean rabbit numbers observed on homogeneous landscape............................................ 13Table 4. Mean rabbit density for surveyed land class in Parwan Valley........................................ 13Table 5. Characteristics of biomass at given sites .......................................................................... 13Table 6. Components of landscape of the vegetated area on the lower slopes in 1978.................. 14Table 7. Empirical model parameters ............................................................................................. 15Table 8 Costs for supply of poisoned carrots ................................................................................. 16Table 9 Costs of fencing ................................................................................................................. 17Table 10 Summary of costs ............................................................................................................ 17
RABBIT CONTROL IN THE PARWAN VALLEY ANDITS VALUE FOR CATCHMENT MANAGEMENTSeptember 1995R. HARTLAND AND M.P. PAPWORTHCentre for Land Protection Research, Department of Conservation & NaturalResources, 5/250 Victoria Pde, East Melbourne. Vic. 3002ABSTRACTThe highly eroded slopes of the White Elephant Hills provide ideal harbour for a rabbit population which can disperse readily intothe surrounding farmlands. The nature of the terrain makes eradicating rabbits from these sites extremely difficult. Rabbits areimplicated in the major soil erosion problems of the area. Rabbit numbers fell to very low levels during the 1982-83 drought, andthe opportunity was taken to intensify rabbit control measures. It was recognized that the problem would be much more difficult toaddress when rabbit numbers were high.Maintenance of very low rabbit numbers has been achieved by fencing off small areas and then targeted poisoning at sites of rabbitactivity. Consequently, there has been a dramatic increase in the regeneration of trees, shrubs and grasses, and particularly in thesurvival of tree and shrub seedlings over much of the White Elephant Reserve. Experimental equipment already in place hasidentified a 20% decrease in average annual surface run-off, attributed to the greater biomass with increased infiltration andevapotranspiration.This increase in pasture production corresponds in general terms to an improvement in the gross margin of approximately 1DSE/ha. The implications of rabbit control for catchment management both in the Parwan valley and more generally are examined.1. INTRODUCTIONSome fifty years ago, interest in the Parwan valley was initiated bytwo processes, erosion and sediment transport. It was recorded thatMelton reservoir was rapidly losing its water capacity as it filledwith sediment. The high sedimentation rate was the result ofexcessive soil erosion, predominantly from the Parwan Valley.The Parwan Creek catchment occupies only 17% of the totalcatchment area above Melton reservoir.The Parwan experimental area was established in 1953 by the SoilConservation Authority. It is located within the White ElephantReserve, now owned by the Victorian government (figure 1).The objectives in establishing the project were to gain a greaterunderstanding of the hydrological processes operating in an erodedcatchment, to determine the relationship between rainfall and runoff,and to evaluate the effects of remedial land use and pastoralpractices.While certain management factors have been deliberatelymanipulated, rabbit infestation has varied across the experimentalcatchments. The length of record enables some assessments to bemade of these changes.2. DESCRIPTION OF THE SITE2.1 LocationThe White Elephant Reserve covers some 300 ha, and islocated about 16 km south-west of Bacchus Marsh, 53 kmwest of Melbourne, Victoria (figure 1). The Parwanexperimental area covers 94.5 ha and is located within theReserve. Coordinates of the area are latitude 37°41' south,longitude 144°20' east. There are seven referencesubcatchments within the area. The orientation of thesubcatchments is shown in figure 1, and somecharacteristics are given in table 1.2.2 InstrumentationClimate data is collected at a meteorology station locatedwithin the area (figure 1). There is a continual record of thekey climatic factors (rainfall amount and intensity, windspeed and direction, temperature and humidity and panevaporation). Surface run-off from the six smallsubcatchments is recorded through a 300mm H-type flumeconnected to a stilling chamber. Surface run-off from themain channel is estimated by a 120° broad-crested weir andfloat recorder. In 1978, a sharp-crested weir was installed.Water level is recorded on L & S type A35 recorders. Amore detailed description of the instrumentation is given inWu (1980) and Wu et al. (1986). The average annualrainfall is approximately 530 mm, while average annualevaporation is 1540 mm, a deficit in the annual waterbalance of 1010 mm.
Page 1 and 2: RABBIT CONTROL IN THE PARWAN VALLEY
Page 3: CONTENTSABSTRACT...................
Page 7 and 8: Table 1. Some characteristics of th
Page 9 and 10: Figure 2. White Elephant Reserve sh
Page 11 and 12: Figure 3. Location of transect in P
Page 13 and 14: Table 3. Mean rabbit numbers observ
Page 15 and 16: Table 7. Empirical model parameters
Page 17 and 18: given in table 9.$16.00/ha. Second,
Page 19 and 20: maintenance as a successful tool in
Page 21: Dunin, F.X., 1965. The effect of ve

Rabbit control in the Parwan Valley and its value for catchment

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