Avoiding the subject: the implications of avoidance behaviour for detecting predators. Fancourt, B. A. 2016.
Avoiding the subject: the implications of avoidance behaviour for detecting predators [link]Paper  doi  abstract   bibtex   
Estimating predator abundance can be challenging. Many predators are inherently difficult to detect due to their low population densities, large home ranges and cryptic behaviour. Detection rates derived from camera traps, spotlight surveys and track counts in sand plots are often used as indices of abundance. However, many factors can influence a species' detection rate and the extent to which it might reflect the species' actual abundance. I investigated the relationships between detections, abundance and activity of two sympatric predators, the Tasmanian devil (Sarcophilus harrisii) and the feral cat (Felis catus). I used camera traps to detect devils and feral cats across eastern Tasmania in southern Australia, where devil populations have progressively and variably declined since 1996 following the spread of the fatal devil facial tumour disease. Devil and cat detections on individual cameras were negatively correlated; however, this was unrelated to abundance. While cats and devils were detected at nearly all of the same sites, cats appeared to avoid devils over short distances, suggesting that negative relationships in detections at the camera scale may reflect fine-scale behavioural avoidance rather than suppression of abundance. These findings highlight the importance of understanding avoidance behaviour when designing surveys to detect predators and when using indices to infer interactions or numerical relationships among sympatric predators. These findings also provide a cautionary tale that highlights the need to consider alternative hypotheses to explain observed patterns, as the implications for species conservation and management outcomes could vary dramatically.
@Report{Fancourt2016,
  author    = {Fancourt, Bronwyn A.},
  title     = {Avoiding the subject: the implications of avoidance behaviour for detecting predators},
  year      = {2016},
  pages     = {1--12},
  doi       = {10.1007/s00265-016-2162-7},
  url       = {http://dx.doi.org/10.1007/s00265-016-2162-7},
  abstract  = {Estimating predator abundance can be challenging. Many predators are
	inherently difficult to detect due to their low population densities,
	large home ranges and cryptic behaviour. Detection rates derived
	from camera traps, spotlight surveys and track counts in sand plots
	are often used as indices of abundance. However, many factors can
	influence a species' detection rate and the extent to which it might
	reflect the species' actual abundance. I investigated the relationships
	between detections, abundance and activity of two sympatric predators,
	the Tasmanian devil (Sarcophilus harrisii) and the feral cat (Felis
	catus). I used camera traps to detect devils and feral cats across
	eastern Tasmania in southern Australia, where devil populations have
	progressively and variably declined since 1996 following the spread
	of the fatal devil facial tumour disease. Devil and cat detections
	on individual cameras were negatively correlated; however, this was
	unrelated to abundance. While cats and devils were detected at nearly
	all of the same sites, cats appeared to avoid devils over short distances,
	suggesting that negative relationships in detections at the camera
	scale may reflect fine-scale behavioural avoidance rather than suppression
	of abundance. These findings highlight the importance of understanding
	avoidance behaviour when designing surveys to detect predators and
	when using indices to infer interactions or numerical relationships
	among sympatric predators. These findings also provide a cautionary
	tale that highlights the need to consider alternative hypotheses
	to explain observed patterns, as the implications for species conservation
	and management outcomes could vary dramatically.},
  file      = {:Fancourt2016.pdf:PDF},
  issn      = {1432-0762},
  journal   = {Behavioral Ecology and Sociobiology},
  owner     = {Tiago Marques},
  timestamp = {2016.06.20},
}
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