Distribution and Survival of a Rare Mammal the Pacarana Dinomys Branickii.
Saavedra, Carlos; Corrales Escobar, Juan David; Corrales, Juan; Giraldo, Juan; Kattan, Gustavo
The pacarana (Dinomys branickii) is Vulnerable; it´s threatened by habitat loss and hunting. This is a relatively large body sized Neotropical rodent whose distribution is associated with the Andes and the western Amazonian piedmont. The pacarana is considered a rare species mainly because it is uncommon in the terrestrial mammal diversity sampling; an observation probably linked to its reproductive pattern (long gestation periods, small litter size and long longevity) which is associated with a slow population growth and also to a patchy resource distribution. This research evaluated the factors associated with the species presence through two ecological approaches: distribution and population viability. We analyzed the distribution using Maxent distribution model for its entire extent of occurrence with 180 records and 15 environmental variables. We conducted a population viability analysis (PVA) based on captive population and field data using the program Vortex. We made a survivorship probabilities analysis for hypothetical populations under different hunting scenarios. Topography was the most important factor associated with the species’ presence in its potential range. Pacarana’s distribution is associated with topographical diversity, steep slopes, high precipitation in the warmest quarter and a narrow range of annual temperature variation. The PVA showed populations are sensitive to changes in reproduction and extraction rates. The persistence of pacarana populations depends mainly on the availability of females. This rare species has life history characteristics that result in low population growth and it does not support the hunting pressure that may occur in throughout its distribution. Factors associated with the distribution of pacarana are abiotic (primarily topography) and biotic related to dispersal ability, and population aspects related to life history characteristics. This permits to confirm that pacarana is a rare species prone to extinction.

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