Detectability Counts when Assessing Populations for Biodiversity Targets
2011

Assessing Brown Hare Populations for Biodiversity Targets

Sample size: 7 publication Evidence: moderate

Author Information

Author(s): Petrovan Silviu O., Ward Alastair I., Wheeler Philip

Primary Institution: Centre for Environmental and Marine Sciences, University of Hull

Hypothesis

Does nighttime surveying improve the accuracy of brown hare population density estimates compared to daytime surveying?

Conclusion

Nighttime surveys significantly improve the detection and density estimates of brown hares compared to daytime surveys.

Supporting Evidence

  • Nighttime encounter rates were 7.4 times higher than daytime rates.
  • Mean pooled density estimates for daytime surveys were 41.2 hares km−2, while nighttime estimates were 32.3 hares km−2.
  • The study found a significant difference in detection rates between day and night surveys.

Takeaway

Counting brown hares at night helps find more of them than counting during the day, which is important for protecting these animals.

Methodology

Line transect distance sampling was used to compare hare densities between daytime and nighttime surveys across seven sites.

Potential Biases

Potential bias from non-random placement of survey transects and low daytime detectability.

Limitations

The study's findings may not be generalizable to all habitats or species due to specific conditions in the surveyed areas.

Statistical Information

P-Value

0.31

Confidence Interval

95% CI 18–23 km−2

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0024206

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