Error(s) in re-building vignettes:
--- re-building ‘Bootstrapping.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available because the rmarkdown package is not available. Did you forget to add it to Suggests in DESCRIPTION? Please see https://github.com/yihui/knitr/issues/1864 for more information.
Quitting from lines 51-59 (Bootstrapping.Rmd) 
Error: processing vignette 'Bootstrapping.Rmd' failed with diagnostics:
unused arguments (control = list(50, 1e-05, 0.0009765625, FALSE, FALSE, 0, FALSE), trace = FALSE)
--- failed re-building ‘Bootstrapping.Rmd’

--- re-building ‘Models-and-Functions.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available because the rmarkdown package is not available. Did you forget to add it to Suggests in DESCRIPTION? Please see https://github.com/yihui/knitr/issues/1864 for more information.
--- finished re-building ‘Models-and-Functions.Rmd’

--- re-building ‘nlraa-AgronJ-paper.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available because the rmarkdown package is not available. Did you forget to add it to Suggests in DESCRIPTION? Please see https://github.com/yihui/knitr/issues/1864 for more information.
Quitting from lines 85-87 (nlraa-AgronJ-paper.Rmd) 
Error: processing vignette 'nlraa-AgronJ-paper.Rmd' failed with diagnostics:
covariate must be numeric
--- failed re-building ‘nlraa-AgronJ-paper.Rmd’

--- re-building ‘nlraa-Oddi-LFMC.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available because the rmarkdown package is not available. Did you forget to add it to Suggests in DESCRIPTION? Please see https://github.com/yihui/knitr/issues/1864 for more information.
Quitting from lines 54-61 (nlraa-Oddi-LFMC.Rmd) 
Error: processing vignette 'nlraa-Oddi-LFMC.Rmd' failed with diagnostics:
error in evaluating the argument 'x' in selecting a method for function 'plot': attempt to set an attribute on NULL
--- failed re-building ‘nlraa-Oddi-LFMC.Rmd’

--- re-building ‘nlraa.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  The vignette engine knitr::rmarkdown is not available because the rmarkdown package is not available. Did you forget to add it to Suggests in DESCRIPTION? Please see https://github.com/yihui/knitr/issues/1864 for more information.
--- finished re-building ‘nlraa.Rmd’

SUMMARY: processing the following files failed:
  ‘Bootstrapping.Rmd’ ‘nlraa-AgronJ-paper.Rmd’ ‘nlraa-Oddi-LFMC.Rmd’

Error: Vignette re-building failed.
Execution halted