@article{collazo_krachey_pollock_perez-aguilo_zegarra_mignucci-giannoni_2019, title={Population estimates of Antillean manatees in Puerto Rico: an analytical framework for aerial surveys using multi-pass removal sampling}, volume={100}, ISSN={["1545-1542"]}, DOI={10.1093/jmammal/gyz076}, abstractNote={AbstractEffective management of the threatened Antillean manatee (Trichechus manatus manatus) in Puerto Rico requires reliable estimates of population size. Estimates are needed to assess population responses to management actions, and whether recovery objectives have been met. Aerial surveys have been conducted since 1976, but none adjusted for imperfect detection. We summarize surveys since 1976, report on current distribution, and provide population estimates after accounting for apparent detection probability for surveys between June 2010 and March 2014. Estimates in areas of high concentration (hotspots) averaged 317 ± 101, three times higher than unadjusted counts (104 ± 0.56). Adjusted estimates in three areas outside hotspots also differed markedly from counts (75 ± 9.89 versus 19.5 ± 3.5). Average minimum island-wide estimate was 386 ± 89, similar to the maximum estimate of 360 suggested in 2005, but fewer than the 700 recently suggested by the Puerto Rico Manatee Conservation Center. Manatees were more widespread than previously understood. Improving estimates, locally or island-wide, will require stratifying the island differently and greater knowledge about factors affecting detection probability. Sharing our protocol with partners in nearby islands (e.g., Cuba, Jamaica, Hispaniola), whose populations share genetic make-up, would contribute to enhanced regional conservation through better population estimates and tracking range expansion.El manejo efectivo del manatí antillano amenazado en Puerto Rico requiere estimados de tamaños de poblaciónes confiables. Dichas estimaciones poblacionales son necesarias para evaluar las respuestas a las acciones de manejo, y para determinar si los objetivos de recuperación han sido alcanzados. Se han realizado censos aéreos desde 1976, pero ninguno de ellos han sido ajustados para detecciones imperfectas. Aquí resumimos los censos desde 1976, actualizamos la distribución, y reportamos los primeros estimados poblacionales ajustados para la probabilidad de detección aparente en los censos de Junio 2010 a Marzo 2014. Las estimaciones poblacionales en áreas de mayor concentración del manatí promedió 317 ± 103, tres veces más abundante que los conteos sin ajuste (104 ± 0.56). Las estimaciones poblacionales en tres áreas fuera de las áreas de mayor concentración del manatí también fueron marcadamente diferentes (75 ± 9.89 vs 19.5 ± 3.5). El estimado mínimo poblacional en la isla entera fue de 386 ± 89, similar al estimado máximo de 360 sugerido en el año 2005, pero menor a los 700 sugeridos recientemente por el Centro de Conservación de Manatíes de Puerto Rico. Documentamos que el manatí tiene una distribución más amplia de lo que se sabía con anterioridad. El mejoramiento de los estimados poblacionales locales o a nivel de isla requerirá que se estratifique a la isla en forma diferente y que se investiguen los factores que influencian a la probabilidad de detección. Compartir protocolos como este con colaboradores de islas vecinas (por. ej., Cuba, Jamaica, Española), cuyas poblaciones de manatíes comparten material genético, contribuiría a la conservación regional mediante mejores estimaciones poblacionales y monitoreo de la expansión de su ámbito doméstico.}, number={4}, journal={JOURNAL OF MAMMALOGY}, author={Collazo, Jaime A. and Krachey, Matthew J. and Pollock, Kenneth H. and Perez-Aguilo, Francisco J. and Zegarra, Jan P. and Mignucci-Giannoni, Antonio A.}, year={2019}, month={Jul}, pages={1340–1349} }
 @article{boone_merrick_krachey_2014, title={A Hellinger distance approach to MCMC diagnostics}, volume={84}, number={4}, journal={Journal of Statistical Computation and Simulation}, author={Boone, E. L. and Merrick, J. R. W. and Krachey, M. J.}, year={2014}, pages={833–849} }
 @article{porter_deperno_krings_krachey_braham_2014, title={Vegetative Impact of Feral Horses, Feral Pigs, and White-tailed Deer on the Currituck National Wildlife Refuge, North Carolina}, volume={79}, ISSN={["1938-4386"]}, DOI={10.2179/13-037}, abstractNote={ABSTRACT  The Currituck National Wildlife Refuge (CNWR) in North Carolina is inhabited by feral horses (Equus caballus), feral pigs (Sus scrofa), and white-tailed deer (Odocoileus virginianus). The impact of these species on the vegetation of CNWR is unknown. To assess impact, we created two replicate exclosure plots within maritime forests, brackish marshes, and maritime grasslands. An electric fence divided each habitat into two sections: including or excluding horses. On each side of the electric fence within each habitat, we sampled three different 5 × 5 m plots (i.e., 36 plots). The first was a fenced exclosure 3 m high, the second a fenced exclosure raised 1 m above the ground and extended to 3 m, and the third, a control, was not fenced. Within plots, we created two 1 m transects, and randomly selected and tagged grasses, forbs, shrubs, and trees. We measured the distances from base to tip of herbs and from branching point to terminal bud in shrubs. We used a linear model to analyze plant growth rate. We used a length ratio adjusted by the number of days as the response variable. Out of 1,105 tagged plants, we detected 87 disturbances; 80 where horses were present and 7 where horses were excluded. Overall, horses were responsible for 84% of disturbances. Most disturbances occurred in brackish marshes on Schoenoplectus pungens. We detected a significant effect of exclosure treatment on plant growth rate where horses were present (p = 0.035), but not where they were excluded (p = 0.32).}, number={1}, journal={CASTANEA}, author={Porter, Kimberly M. and DePerno, Christopher S. and Krings, Alexander and Krachey, Matthew and Braham, Richard}, year={2014}, month={Mar}, pages={8–17} }
 @article{blackman_deperno_heiniger_krachey_moorman_peterson_2011, title={Effects of crop field characteristics on nocturnal winter use by American woodcock}, volume={76}, ISSN={0022-541X}, url={http://dx.doi.org/10.1002/JWMG.254}, DOI={10.1002/jwmg.254}, abstractNote={AbstractSince the late 1960s, American woodcock (Scolopax minor) have undergone population declines because of habitat loss. Previous research suggested ridge and furrow topography in conventionally tilled soybean fields provided critical nocturnal cover as birds foraged on earthworms. However, the use of no‐till technology has increased and many fields now lack ridge and furrow topography. We assessed woodcock winter nocturnal foraging habitat use given recent changes in agricultural technology, and investigated how field treatment, earthworm abundance, and environmental variables affect the selection of nocturnal foraging sites. We counted woodcock along transects in 5 field treatments twice in each of 67 fields during December–March 2008–2009 and 72 fields during December–March 2009–2010. During both seasons, we collected earthworm and soil samples from a subset of fields of each field treatment. Woodcock densities were at least twice as high in no‐till soybean fields planted after corn and in undisked corn fields with mowed stalks than in other field treatments. No‐till soybean planted after corn and undisked corn fields contained ridge and furrow topography, whereas other crops did not, and earthworms were at least 1.5 times more abundant in no‐till soybean fields than other field treatments. Ridges and furrows in no‐till soybean fields planted after corn and undisked corn fields may provide wintering woodcock with thermal protection and concealment from predators. No‐till soybean fields planted after corn offered the additional benefit of relatively high food availability. The presence of ridge and furrow topography can be used to predict woodcock field use on the wintering grounds in agricultural areas. Farmers can provide nocturnal winter foraging sites for woodcock by delaying field disking and leaving ridge and furrow topography in crop fields. © 2011 The Wildlife Society.}, number={3}, journal={The Journal of Wildlife Management}, publisher={Wiley}, author={Blackman, Emily B. and Deperno, Christopher S. and Heiniger, Ron W. and Krachey, Matthew J. and Moorman, Christopher E. and Peterson, M. Nils}, year={2011}, month={Nov}, pages={528–533} }