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Once believed extinct in the wild, the only known wild long-tailed chinchillas (Chinchilla lanigera) exist in north central Chile (Jiménez, 1995). Both species of chinchillas and their range decreased dramatically as millions were exported from Chile for the fur trade (Albert, 1900). In Chile, both species are listed as endangered and are protected from international trade by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), Appendix 1 (CONAF 1988, IUCN 1972). Population estimates of C. lanigera vary from less than 1000 to approximately 5000 (Jiménez, 1995; Mohlis pers. comm.). Based on colony size and densities reported by Jiménez (1995:92), approximately 4050 individuals were known to exist in Aucó, Chile as of 1990. At that time, the population was declining (Jiménez1995). All prior research reported a deterioration of chinchilla habitat over the last few hundred years. Enhancing the habitat meant learning what and where was chinchilla habitat. This paper is meant to explain the methods used to study the chinchilla habitat and common techniques used to evaluate wildlife, which aim to define conservation priorities.
Site definition and methods: To be comparable with prior studies it is advisable to mimic the prior researchers’ methods. Our grids are duplicated from those used by Jiménez (1990) in his studies of wild chinchillas. By mimicking his methods, our data is comparable over a long time-period. For example, we have a descriptive record of the plants associated with chinchillas for the last 30 years. It is these plant species that our restoration efforts are focused on.
Four permanent trapping grids consisting of 49 stations per grid in a 7×7 configuration were placed on north facing mountain slopes of two different drainage basins in Aucó, Chile. The distance between grids varies based on the location of chinchilla colonies, and within each grid, stations were spaced 15m [49.21ft.] apart. Each column is labeled A to G and each row 1 to 7. At each station, 30cm [11.8in.] red wooden stakes are labeled with the station number and hammered into the ground. Be consistent with one grid layout. For example, the lower left corner is A1 and the last station G7 is located at the upper right corner of the grid. The purpose of grids is to estimate the type and distribution of animal species using the vegetation and ground cover. For example, you may want three grids in known occupied areas, and others in restoration areas, and presumed unoccupied areas. This helps in understanding the relationship between ground cover and vegetation types, and the animals that prefer that environment.
Vegetation measurements: To calculate total vegetation cover, species’ frequencies and abundance, we used the line intercept method. In each grid described earlier, we analyzed 16 transects, each measuring 18.5m [~61ft.] in length, compensating for topographic variations. Use a rope 18.5m long and a measuring tape to measure all ground cover along the line. Record ground cover type or species and its length in cm. For each grid, the total area measured for all transects was used to calculate cover. First, placement of transects within grids was created using a random number list. Four random numbers were used to identify each location. The first number identified the starting position by column for each transect. The second number identified the starting position by row. The third number identified if the transect was to be placed to the right or left of the trap station. The fourth number designated if the transect was to go up or down slope from the station at a 45-degree angle. Once data was gathered it was analyzed in a spreadsheet program. One can calculate cover by unit length covered by species or cover type divided by the total unit length measured in transect. In our case, sometimes the slope of the landscape and overlapping shrub crowns resulted in transect total area measures being greater than or less than the 18.5m long transect. Therefore, percentage ground cover (not just transect) would be calculated, for example, in the following manner: (...)