@article{fdi:010049496,
  title = {{C}omparative efficiency and accuracy of variable area transects versus square plots for sampling tree diversity and density},
  author = {{N}ath, {C}. {D}. and {P}elissier, {R}apha{\¨e}l and {G}arcia, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}groforestry systems have been recognized as areas with high conservation potential, and there is a need to quickly assess the biodiversity and tree stocking density available in these systems. {H}owever, it is not clear if the commonly used fixed area plot is most efficient for sampling such landscapes, or if a different method could provide equivalent data with less effort. {T}hus, a field and simulation-based study was carried out to compare the efficiency and accuracy of a variable area transect versus the fixed area square plot. {F}ield efficiency tests were carried out in three habitat types, robusta coffee plantations, arabica coffee plantations and a privately owned forest fragment, in {K}odagu, southern {I}ndia. {A} simulation study of bias, precision and accuracy of the two methods for tree density estimation also was carried out using various spatial distribution patterns and densities. {T}he variable area transect was significantly more efficient per unit effort in the field than the fixed area square plot. {I}n the simulation tests both methods performed equally well under random spatial distribution. {H}owever, under simulated aggregated distribution both methods were positively biased (square plot up to 12% at low density, variable area transect 9-12% at all densities), and under simulated regular distribution the variable area transect was slightly negatively biased (-5 to -7% at medium to high density). {T}he variable area transect thus can be recommended over the square plot for rapid assessment of tree diversity and density, when the vegetation is expected to be randomly dispersed.},
  keywords = {{M}an-hours ; {B}ias ; {P}recision ; {S}patial dispersion ; {C}offee agroforestry ; {I}ndia},
  booktitle = {},
  journal = {{A}groforestry {S}ystems},
  volume = {79},
  numero = {2},
  pages = {223--236},
  ISSN = {0167-4366},
  year = {2010},
  DOI = {10.1007/s10457-009-9255-5},
  URL = {https://www.documentation.ird.fr/hor/fdi:010049496},
}