An ecologist uses the mark-release-recapture method to estimate the population density of the violet ground beetle (Carabus violaceus) in a nature reserve with an area of 2.5 hectares2.5\text{ hectares}2.5 hectares.
In the first sampling period, 120 beetles are captured, marked with a non-toxic paint, and released. In the second sampling period, 150 beetles are captured, of which 30 are found to be marked.
Assuming the population is closed and the marking method does not affect survival or recapture probability, what is the estimated population density of Carabus violaceus in this nature reserve?
192 beetles ha−1192\text{ beetles ha}^{-1}192 beetles ha−1
240 beetles ha−1240\text{ beetles ha}^{-1}240 beetles ha−1
600 beetles ha−1600\text{ beetles ha}^{-1}600 beetles ha−1
1500 beetles ha−11500\text{ beetles ha}^{-1}1500 beetles ha−1
