An optimization approach to the two-circle method of estimating ground-dwelling arthropod densities
Date
2014-06
Journal Title
Journal ISSN
Volume Title
Publisher
Florida Entomological Society
Abstract
Information on ground-dwelling arthropod densities is important for efficient management
in agro-ecosystems. A method of using paired pitfall traps with different inter-trap distances,
called the two-circle method (TCM), was proposed recently for accurate and efficient
estimation of arthropod densities. Using the numbers of individuals caught in paired traps
and the inter-trap distances between the paired traps as input, the TCM can simultaneously
estimate the effective trapping radius and the population density by fitting a nonlinear
model. However, the previous fitting procedure (using the nonlinear least squares approach)
provides the estimates and standard errors of only these two variables, and often suffers
from its hypersensitivity to the initial values assigned in the nonlinear regression. To estimate
the confidence intervals of these estimates and to assess the effects of the number of
replications per distance class and the number of distance classes on the accuracy of density
estimates, we provide a new procedure for fitting the model by using the optimization function.
Evaluation based on simulated and field data suggests that the TCM could provide a
reliable estimate of density by using at least 15 paired traps per distance class and at least
4 distance classes.
Description
CITATION: Shi, P-J. et al. 2014. An optimization approach to the two-circle method of estimating ground-dwelling arthropod densities. Florida Entomologist, 97(2):644-652.
The original publication is available at http://journals.fcla.edu/flaent
The original publication is available at http://journals.fcla.edu/flaent
Keywords
Arthropoda
Citation
Shi, P-J. et al. 2014. An optimization approach to the two-circle method of estimating ground-dwelling arthropod densities. Florida Entomologist, 97(2):644-652.