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Effects of Hunting on a Puma Population in Colorado

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Abstract

We investigated effects of regulated hunting on a puma (Puma concolor) population on the Uncompahgre Plateau (UPSA) in southwestern Colorado, USA. We examined the hypothesis that an annual harvest rate averaging 15% of the estimated number of independent individuals using the study area would result in a stable or increasing abundance of independent pumas. We predicted hunting mortality would be compensated by 1) a reduction in other causes of mortality, thus overall survival would stay the same or increase; 2) increased reproduction rates; or 3) increased recruitment of young animals. The study occurred over 10 years (2004–2014) and was designed with a reference period (years 1–5; i.e., RY1–RY5) without puma hunting and a treatment period (years 6–10; i.e., TY1–TY5) with hunting. We captured and marked pumas on the UPSA and monitored them year‐round to examine their demographics, reproduction, and movements. We estimated abundance of independent animals using the UPSA each winter during the Colorado hunting season from reference year 2 (RY2) to treatment year 5 (TY5) using the Lincoln‐Petersen method. In addition, we surveyed hunters to investigate how their behavior influenced harvest and the population. We captured and marked 110 and 116 unique pumas in the reference and treatment periods, respectively, during 440 total capture events. Those animals produced known‐fate data for 75 adults, 75 subadults, and 118 cubs, which we used to estimate sex‐ and life stage‐specific survival rates. In the reference period, independent pumas more than doubled in abundance and exhibited high survival. Natural mortality was the major cause of death to independent individuals, followed by other human causes (e.g., vehicle strikes, depredation control). In the treatment period, hunters killed 35 independent pumas and captured and released 30 others on the UPSA. Abundance of independent pumas using the UPSA declined 35% after 4 years of hunting with harvest rates averaging 15% annually. Harvest rates at the population scale, including marked independent pumas with home ranges exclusively on the UPSA, overlapping the UPSA, and on adjacent management units were higher, averaging 22% annually in the same 4 years leading to the population decline. Adult females comprised 21% of the total harvest. The top‐ranked model explaining variation in adult survival () indicated a period effect interacting with sex. Annual adult male survival was higher in the reference period ( = 0.96, 95% CI = 0.75–0.99) than in the treatment period ( = 0.40, 95% CI = 0.22–0.57). Annual adult female survival was 0.86 (95% CI = 0.72–0.94) in the reference period and 0.74 (95% CI = 0.63–0.82) in the treatment period. The top subadult model showed that female subadult survival was constant across the reference and treatment periods ( = 0.68, 95% CI = 0.43–0.84), whereas survival of subadult males exhibited the same trend as that of adult males: higher in the reference period ( = 0.92, 95% CI = 0.57–0.99) and lower in the treatment period ( = 0.43, 95% CI = 0.25–0.60). Cub survival was best explained by fates of mothers when cubs were dependent (mother alive = 0.51, 95% CI = 0.35–0.66; mother died = 0.14, 95% CI = 0.03–0.34). The age distribution for independent pumas skewed younger in the treatment period. Adult males were most affected by harvest; their abundance declined by 59% after 3 hunting seasons and we did not detect any males >6 years old after 2 hunting seasons. Pumas born on the UPSA that survived to subadult stage exhibited both philopatry and dispersal. Local recruitment and immigration contributed to positive growth in the reference period, but recruitment did not compensate for the losses of adult males and partially compensated for losses of adult females in the treatment period. Average birth intervals were similar in the reference and treatment periods (reference period = 18.3 months, 95% CI = 15.5–21.1; treatment period = 19.4 months, 95% CI = 16.2–22.6), but litter sizes (reference period = 2.8, 95% CI = 2.4–3.1; treatment period = 2.4, 95% CI = 2.0–2.8) and parturition rates (reference period = 0.63, 95% CI = 0.49–0.75; treatment period = 0.48, 95% CI = 0.37–0.59) declined slightly in the treatment period. Successful hunters used dogs, selected primarily males, and harvested pumas in 1–2 days (median). We found that an annual harvest rate at the population scale averaging 22% of the independent pumas over 4 years and with >20% adult females in the total harvest greatly reduced abundance. At this scale, annual mortality rates of independent animals from hunting averaged 6.3 times greater than from all other human causes and 4.6 times greater than from all natural causes during the population decline. Hunting deaths were largely additive and reproduction and recruitment did not compensate for this mortality source. Hunters generally selected male pumas, resulting in a decline in their survival and abundance, and the age structure of the population. We recommend that regulated hunting in a source‐sink structure be used to conserve puma populations, provide sustainable hunting opportunities, and address puma‐human conflicts. © 2021 The Wildlife Society. Investigamos los efectos de la cacería regulada en la población de pumas (Puma concolor) de la Uncompahgre Plateau (UPSA) en el suroeste de Colorado, USA. Exploramos la hipótesis de que una cosecha anual con una tasa promedio del 15% del número estimado de pumas independientes que están usando el área de estudio resultaría en una abundancia estable o un incremento de pumas independientes. Nuestra predicción de que la mortalidad por cacería seria compensada por: 1) una reducción en otras causas de mortalidad, por lo tanto, la supervivencia se mantendría igual o incrementaría; 2) un incremento en la tasa reproductiva; o 3) un incremento en el reclutamiento de pumas jóvenes. Este estudio se llevó a cabo a lo largo de 10 años (2004–2014) y fue diseñado con un periodo de referencia (años 1 al 5; RY1–RY5) sin cacería de pumas y un periodo de tratamiento (años 6–10; i.e., TY1–TY5) con cacería de pumas. Capturamos y marcamos pumas en la UPSA y se llevó a cabo el monitoreo a lo largo de todo el año para examinar la demografía, reproducción y movimientos de los pumas. Estimamos la abundancia de pumas independientes que usaban la UPSA cada invierno durante la estación de cacería de pumas en Colorado usando el año 2 (RY2) como referencia al año de tratamiento 5 (TY5) usando el método de Lincoln‐Petersen. Adicionalmente, llevamos a cabo prospecciones con cazadores para investigar como el comportamiento de los cazadores influía la cosecha y la población de pumas. Capturamos y marcamos un total de 110 y 116 pumas únicos dentro del periodos de referencia y de tratamiento, respectivamente, a lo largo de un total de 440 eventos de captura. Esos pumas produjeron datos de mortalidad con información conocida para 75 adultos, 75 sub‐adultos y 118 cachorros, con los cuales se estimaron tasas de supervivencia específicas por sexo y etapas de vida. En el periodo de referencia la abundancia de pumas independientes se incrementó a más del doble y exhibieron una supervivencia alta. La mortalidad natural fue la mayor causa de muerte en pumas independientes, seguida de causas producidas por seres humanos (e.g. atropellamientos, control de depredadores). En el periodo de tratamiento, los cazadores mataron 35 pumas independientes, adicionalmente capturaron y dejaron en libertad a 30 pumas en la UPSA. La abundancia de pumas independientes se redujo en un 35% después de 4 años de cacería con tasas de aprovechamiento con un promedio anual de 15% en la UPSA. Las tasas de aprovechamiento a la escala de población incluyendo pumas independientes marcados con ámbitos hogareños exclusivos dentro de la UPSA, con sobreposición en la UPSA y en unidades adyacentes de manejo fueron mayores, en promedio 22% anualmente durante los mismos 4 años que llevaron a la población al declive. Las hembras adultas comprendieron 21% de la cosecha total. El mejor modelo que explicaba la variación en la supervivencia () de los adultos indicaba un efecto del periodo interactuando con el sexo. La supervivencia anual de los machos fue más alta durante el periodo de referencia ( = 0.96, 95% CI = 0.75–0.99) que durante el periodo de tratamiento ( = 0.40, 95% CI = 0.22–0.57). La supervivencia anual de las hembras fue 0.86 (95% CI = 0.72–0.94) en el periodo de referencia y 0.74 (95% CI = 0.63–0.82) durante el tratamiento. El mejor modelo de supervivencia en hembras sub‐adultas, mostro que la supervivencia fue constante a través de los periodos de referencia y tratamiento ( = 0.68, 95% CI = 0.43–0.84), donde la supervivencia de los machos sub‐adultos exhibió el mismo patrón de supervivencia de los machos adultos: más alta en el periodo de referencia ( = 0.92, 95% CI = 0.57–0.99) y menor en el periodo de tratamiento ( = 0.43, 95% CI = 0.25–0.60). La supervivencia de los cachorros se explica mejor por el destino de sus madres, cuando estos son dependientes (madres vivas = 0.51, 95% CI = 0.35–0.66; madres muertas = 0.14, 95% CI = 0.03–0.34). La distribución por edades de los pumas independientes estuvo sesgada a animales jóvenes durante el periodo de tratamiento. Los machos adultos fueron los más afectados por el aprovechamiento, su abundancia se redujo en un 59% después de 3 temporadas de cacería, y una ausencia de machos >6 años de edad después de 2 temporadas de cacería. Los pumas nacidos en la UPSA que sobrevivieron a la etapa sub‐adulta exhibieron características filopátricas y de dispersión. El reclutamiento local y la inmigración contribuyeron al crecimiento positivo en el periodo de referencia. Sin embargo, el reclutamiento no compenso por la pérdida de machos adultos y parcialmente compenso por la pérdida de hembras durante el periodo de tratamiento. El intervalo promedio entre nacimientos fue similar entre los periodos de referencia y tratamiento (periodo de referencia = 18.3 meses, 95% CI = 15.5–21.1; periodo de tratamiento = 19.4 meses, 95% CI = 16.2–22.6), mientras que el tamaño de camada (periodos de referencia = 2.8, 95% CI = 2.4–3.1; periodo de tratamiento = 2.4, 95% CI = 2.0–2.8) y las tasas de parición (periodo de referencia = 0.63, 95% CI = 0.49–0.75; periodo de tratamiento = 0.48, 95% CI = 0.37–0.59) declinaron ligeramente durante el periodo de tratamiento. Cazadores exitosos de pumas usaron perros, seleccionaron fundamentalmente machos y cosecharon pumas en 1−2 días (mediana). Encontramos a la escala de población una tasa de aprovechamiento anual de 22% del número de pumas independientes en un periodo de 4 años y donde >20% de hembras adultas en la cosecha total redujeron en cantidad la abundancia de pumas. A esta escala, las tasas anuales de mortalidad de los pumas independientes por caceria fueron en promedio 6.3 veces mayores que todas las otras causas producidas por seres humanos, y 4.6 veces mayores que todas las causas de mortalidad natural durante la reducción en la población. La mortalidad por cacería era aditiva y la reproducción y el reclutamiento no compensaron a la mortalidad por cacería. Encontramos que los cazadores de pumas seleccionaron pumas machos, resultando en una reducción de la supervivencia, abundancia de machos y la estructura de edades dentro de la población. Recomendamos que la cacería regulada con base en una estructura poblacional de fuente‐sumidero puede ser utilizada para conservar a las poblaciones de pumas, proporcionando oportunidades para la cacería sustentable de pumas y redirigir el conflicto entre pumas y seres humanos. Nous avons examiné les effets d’une chasse régulée sur une population de puma (Puma concolor) dans le plateau de l’Uncompahgre (UPSA) dans le sud‐ouest du Colorado. Nous avons examiné l’hypothèse qu’un taux annuel de récolte de 15% du nombre estimé de pumas indépendants utilisant l’aire d’étude maintiendrait l’abondance ou accroîtrait l’abondance de pumas. Nous avons prédit que la mortalité par la chasse serait compensée par: 1) une réduction des autres causes de mortalité, entrainant une augmentation ou stabilisation de la survie; 2) une augmentation du taux de reproduction; ou 3) une augmentation du recrutement de jeunes individus. L’étude a été conduit durant, et a été construite autour d’une période de référence (années 1 à 5) sans chasse aux pumas et une période de traitement (années 6 à 10) avec une chasse aux pumas. Nous avons capturé et marqué des pumas dans l’aire d’étude (UPSA) et les avons suivis toute l’année pour récolter des données concernant leur démographie, reproduction et mouvement. L’abondance de pumas indépendants a été estimée dans l’USPA à chaque hiver durant la saison de chasse aux pumas au Colorado de l’année de référence 2 (RY2) à l’année de traitement 5 (TY5) en utilisant la méthode de Lincoln‐Petersen. De plus, nous avons sondé les chasseurs afin d’apprendre comment leur comportement influençait la récolte et la population de puma. Durant les périodes de référence et traitement, 110 et 116 pumas ont respectivement été capturés et marqués, durant 440 évènements de capture. Ces pumas ont produit des données dont le sort est connu pour 75 adultes, 75 subadultes, et 118 juvéniles qui ont été utilisés afin de modéliser le taux de survie de chaque sexe et groupe d’âge. Durant la période de référence, l’abondance des pumas indépendants a plus que doublé en abondance et montré un haut taux de survie. La mortalité naturelle était la cause principale de décès, suivie par les mortalités reliées à l’humain. Durant la période de traitement, les chasseurs ont tué 35 pumas indépendants et capturé puis relâché 30 pumas. L’abondance de pumas indépendants a décliné de 35% après 4 années de chasse avec des taux de récolte moyennant 15% dans l’UPSA. Les taux de récoltes à l’échelle de la population incluant des individus dont le domaine vital était à l’intérieur de l’USPA, chevauchant l’USPA, ou en périphérie de l’USPA étaient plus élevés et approchaient 22% durant les quatre années précédant le déclin de la population. Les femelles adultes représentaient 21% de la récolte total. Le meilleur modèle expliquant la variation dans la survie () des adultes incluait un effet de la période en interaction avec le sexe. Le taux de survie des mâles adultes était plus élevé durant la période de référence ( = 0.96, 95% CI = 0.75–0.99) que durant la période de traitement ( = 0.40, 95% CI = 0.22–0.57). Le taux de survie des femelles adultes était de 0.86 (95% CI = 0.72–0.94) durant la période de référence et de 0.74 (95% CI = 0.63–0.82) durant la période de traitement. Le meilleur modèle du taux de survie des femelles subadultes a démontré que la survie était constante entre les deux périodes de traitement ( = 0.68, 95% CI = 0.43–0.84) alors que le taux de survie des mâles subadultes a montré la même tendance que les mâles adultes: plus élevé durant la période de référence ( = 0.92, 95% CI = 0.57–0.99) que durant la période de traitement ( = 0.43, 95% CI = 0.25–0.60). Le taux de survie des petits était le mieux expliqué par le sort de la mère alors que les petits étaient dépendants (mère en vie = 0.51, 95% CI = 0.35–0.66; mère en vie = 0.14, 95% CI = 0.03–0.34). La structure des âges des pumas indépendants a décliné durant la période de traitement. Les mâles adultes étaient les plus affectés par la récolte, leur abondance a décliné de 59% après trois saisons de chasse et aucun individu de plus de 6 ans n’était présent après deux saisons de chasse. Les pumas nés dans l’UPSA qui ont survécu au stage subadulte ont exhibé de la philopatrie et de la dispersion. Le recrutement local et l’immigration ont contribué au taux de croissance durant la période de référence. Le recrutement n’a pas compensé pour la perte de mâles adultes et a compensé partiellement pour la perte de femelles adultes durant la période de traitement. L’intervalle moyen des naissances est demeuré similaire (période de référence = 18.3 mo., 95% CI = 15.5–21.1; période de traitement = 19.4 mo., 95% CI = 16.2–22.6), alors que la taille des portées (période de référence = 2.8, 95% CI = 2.4–3.1; période de traitement = 2.4, 95% CI = 2.0–2.8) et le taux de parturition (période de référence = 0.63, 95% CI = 0.49–0.75; période de traitement = 0.48, 95% CI = 0.37–0.59) ont diminué légèrement durant la période de traitement. Les chasseurs de pumas qui ont eu du succès ont utilisé des chiens, ils sélectionnaient primairement les mâles et ont récolté des pumas à l’intérieur de 1–2 jours (médiane). Nous avons trouvé qu’un taux de récolte moyen avoisinant 22% du nombre estimé de pumas indépendants sur quatre ans et avec >20% de femelles adultes dans la récolte réduisait grandement l’abondance de puma. À cette échelle, le taux de mortalité annuel provenant de la chasse était en moyenne 6.3 fois plus grand que le taux provenant de tous les autres causes de mortalité humaine et 4.6 fois plus grand que le taux de mortalité de source naturelle durant la période de déclin de la population. La mortalité par la chasse était largement additive et la reproduction et le recrutement n’ont pas compensé pour cette source de mortalité. Nous avons trouvé que les chasseurs montraient une sélection pour les pumas mâles, entrainant alors une réduction de la survie et de l’abondance des mâles et impactant la structure des âges de la population. Nous recommandons qu’une chasse régulée dans une structure source‐puit peut être utilisée afin d’aider la conservation des pumas, procurer des opportunités de chasse durable, et adresser les conflits pumas‐humains.

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... If the WDFW Team's criticism (#3) of L&P was instead that the data were not intentionally divided into treatment and control but rather haphazardly divided by events on the ground, then the Team should have considered the possibility of selection bias (e.g., [19,20]. However, that seems unlikely because the WDFW Team cited [42] for their definition of treatment/control, and those authors wrote about their own work, "Our research was an un-replicated case study on 1 geographic area having a before and after treatment effect design without a separate control area where pumas were not hunted." p.5, [42]. ...
... However, that seems unlikely because the WDFW Team cited [42] for their definition of treatment/control, and those authors wrote about their own work, "Our research was an un-replicated case study on 1 geographic area having a before and after treatment effect design without a separate control area where pumas were not hunted." p.5, [42]. That design is very similar to the design in L&P, and furthermore, neither the replicated treatment/controls nor the harvest of pumas in [42] was designed by the researchers. ...
... p.5, [42]. That design is very similar to the design in L&P, and furthermore, neither the replicated treatment/controls nor the harvest of pumas in [42] was designed by the researchers. Probably, L&P produced stronger inference because they compared several different sites at the same time over years. ...
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... In Colorado, 165 samples were taken from 2005 to 2014, primarily from puma populations within the Front Range and the Western Slope. These animals were opportunistically sampled and released during a study investigating puma-human interactions, including the impacts of hunting (53)(54)(55). A total of 248 panther samples were collected in Florida from 1985 to 2015 from ongoing studies, routine monitoring, and documented mortalities. ...
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... References are Big Bend Ranch State Park, Carlsbad and Guadalupe National Parks and Big Bend National Park (Young et al. 2010), South Texas (Harveson et al. 2012), Davis Mountains (Harveson, unpublished data; Harveson et al. 2016).F I G U R E 3 Annual female survival reported for Texas, USA, mountain lion studies. The background color depicts thresholds for female survival that likely reflect population growth (green), stability (yellow) and decline (red), as determined in a review conducted byLogan and Runge (2021). References are Big Bend Ranch State Park, Carlsbad and Guadalupe National Parks and Big Bend National Park(Young et al. 2010); South Texas(Harveson 1997); Davis Mountains(Harveson, unpublished data, Harveson et al. 2016). ...
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The average individual heterozygosity of canonical (non-introgressed) panthers was 0.386 ± 0.012 (SE); for admixed panthers , it was 0.615 ± 0.007. Survival rates were strongly age-dependent (kittens had the lowest survival rates), were positively affected by individual heterozygosity, and decreased with increasing population abundance. Overall annual kitten survival was 0.32 ± 0.09; sex did not have a clear effect on kitten survival. Annual survival of subadult and adult panthers differed by sex; regardless of age, females exhibited higher survival than males. Annual survival rates of subadult, prime adult, and old adult females were 0.97 ± 0.02, 0.86 ± 0.03, and 0.78 ± 0.09, respectively. Survival rates of subadult, prime adult, and old adult males were 0.66 ± 0.06, 0.77 ± 0.05, and 0.65 ± 0.10, respectively. For panthers of all ages, genetic ancestry strongly affected survival rate, where first filial generation (F1) admixed panthers of all ages exhibited the highest rates and canonical (mostly pre-introgression panthers and their post-introgression descendants) individuals exhibited the lowest rates. The most frequently observed causes of death of radio-collared panthers were intraspecific aggression and vehicle collision. Cause-specific mortality analyses revealed that mortality rates from vehicle collision, in-traspecific aggression, other causes, and unknown causes were generally similar for males and females, although males were more likely to die from intraspecific aggression than females. The probability of reproduction and the annual number of kittens produced varied by age; evidence that ancestry or abundance influenced these parameters was weak. Predicted annual probabilities of reproduction were 0.35 ± 0.08, 0.50 ± 0.05, and 0.25 ± 0.06 for subadult, prime adult, and old adult females, respectively. The number of kittens predicted to be produced annually by subadult, prime adult, and old adult females were 2.80 ± 0.75, 2.67 ± 0.43, and 2.28 ± 0.83, respectively. The stochastic annual population growth rate estimated using a matrix population model was 1.04 (95% CI = 0.72-1.41). An individual-based population model predicted that the probability that the population would fall below 10 panthers within 100 years (quasi-extinction) was 1.4% (0-0.8%) if the adverse effects of genetic erosion were ignored. However, when the effect of genetic erosion was considered, the probability of quasi-extinction within 100 years increased to 17% (0-100%). Mean times to quasi-extinction, conditioned on going quasi-extinct within 100 years, was 22 (0-75) years when the effect of genetic erosion was considered. Sensitivity analyses revealed that the probability of quasi-extinction and expected time until quasi-extinction were most sensitive to changes in kitten survival parameters. Without genetic management intervention, the Florida panther population would face a substantially increased risk of quasi-extinction. The question, therefore,-van de Kerk et al. • Florida Panther Population and Genetic Viability 3 is not whether genetic management of the Florida panther population is needed but when and how it should be implemented. Thus, we evaluated genetic and population consequences of alternative genetic introgression strategies to identify optimal management actions using individual-based simulation models. Releasing 5 pumas every 20 years would cost much less ($200,000 over 100 years) than releasing 15 pumas every 10 years ($1,200,000 over 100 years) yet would reduce the risk of quasi-extinction by comparable amount (44-59% vs. 40-58%). Generally, releasing more females per introgression attempt provided little added benefit. The positive effects of the genetic introgression project persist in the panther population after 20 years. We suggest that managers contemplate repeating genetic introgression by releasing 5-10 individuals from other puma populations every 20-40 years. We also recommend that managers continue to collect data that will permit estimation and monitoring of kitten, adult, and subadult survival. We identified these parameters via sensitivity analyses as most critical in terms of their impact on the probability of and expected times to quasi-extinction. The continuation of long-term monitoring should permit the adaptation of genetic management strategies as necessary while collecting data that have proved essential in assessing the genetic and demographic health of the population. The prospects for recovery of the panther will certainly be improved by following these guidelines. RESUMEN La población de pantera de Florida (Puma concolor coryi) mejoró tras la implementación en 1995 del proyecto de introgresión genética en el sur de Florida, USA, como lo demuestran varias líneas de evidencia. Desde entonces, su diversidad genética ha mejorado, la frecuencia de índices morfológicos y biomédicos correlacionados con depresión endogámica ha disminuido, y el tamaño de la población ha aumentado. Sin embargo, la población de panteras permanece pequeña, aislada, y se enfrenta a retos sustanciales producidos por fuerzas determinísticas y estocásticas. Los objetivos de este estudio fueron 1) evaluar exhaustivamente la demografía de la población de panteras de Florida usando datos de campo (del periodo 1981-2015) y modelos con el fin de calibrar en que medida persisten los beneficios adquiridos a través de la introgresión genética y 2) evaluar la efectividad de varias estrategias de manejo genético. La diversidad genética de la población mejoró sustancialmente con la introducción de pumas hembra (Puma concolor stanleyana) procedentes de Texas, USA. En panteras canónicas (no procedentes de in-trogresión), el valor medio de heterocigosidad individual fue 0.386 ± 0.012 (SE), y en panteras mezcladas 0.615 ± 0.007. En gran medida, las tasas de supervivencia dependieron de la edad (los cachorros tenían las tasas de supervivencia más bajas), estuvieron afectadas positivamente por la heterocigosidad individual, y disminuyeron cuando la población aumentó. La tasa de supervivencia total, independientemente del sexo del cachorro, fue de 0.32 ± 0.09. La tasa de supervivencia anual de panteras adultas y subadultas varió según el sexo; independientemente de la edad, las hembras vivieron más que los machos. Las tasas anuales de supervivencia de hembras subadultas, adultas y adultas mayores fueron 0.97 ± 0.02, 0.86 ± 0.03, y 0.78 ± 0.09, respectivamente. Las tasas de supervivencia de machos subadultos, adultos, y adultos mayores fueron 0.66 ± 0.06, 0.77 ± 0.05, y 0.65 ± 0.10, respectivamente. La ascendencia genética determinó en gran medida la tasa de supervivencia de panteras de cualquier edad, siendo mayor en la primera generación filiar (F1) de panteras mezcladas en todas las edades, y menor en los individuos canónicos (sobre todo panteras pre-introgresión y sus descendientes post-introgresión). En panteras con collares de radio telemetría, las causas de mortalidad más frecuentes fueron la agresión intraespecífica y la colisión con vehículos. El análisis de las causas de mortalidad reveló que en las categorías colisión con vehículos, agresión intraespecífica, otras causas y motivos desconocidos, la tasa de mortalidad de machos y hembras era similar, aunque los machos tenían más posibilidades de morir por agresión intraespecífica que las hembras. Las probabilidades de reproducción y el número anual de cachorros dependieron de la edad pero no de los ancestros o el tamaño de la población. Las probabilidades de reproducción de hembras subadultas, adultas, y adultas mayores se estimaron en 0.35 ± 0.08, 0.50 ± 0.05, y 0.25 ± 0.06, respectivamente. El número de cachorros por año y por pantera subadulta, adulta, y adulta mayor se estimó en 2.80 ± 0.75, 2.67 ± 0.43, y 2.28 ± 0.83, respectivamente. Usando un modelo demográfico matricial se estimó la tasa anual de crecimiento estocástico poblacional en 1.04 (95% CI = 0.72-1.41). Usando un modelo de población basado en el individuo e ignorando el impacto adverso de la erosión genética, se estimó la probabilidad de que la población disminuyese a menos de 10 panteras en 100 años (cuasi-extinción) en 1.4% (0-0.8%). Sin embargo, incluyendo el impacto de la erosión genética, la probabilidad de cuasi-extinción en 100 años aumentó al 17% (0-100%). El plazo medio para la cuasi-extinción, asumiendo que la cuasi-extinción ocurre en 4 Wildlife Monographs • 203 100 años e incluyendo el impacto de la erosión genética, fue de 22 (0-75) años. Análisis de sensibilidad demostraron que la probabilidad de cuasi-extinción y el plazo hasta alcanzarla, dependían de los valores utilizados para los parámetros de supervivencia de cachorros. Sin manejo genético, la población de panteras de Florida se enfrentaría a un aumento sustancial del riesgo de cuasi-extinción. Por lo tanto, la pregunta no es si es necesario el manejo genético de la población de las panteras de Florida, sino cuándo y cómo implementarlo. Usando modelos de simulación basados en individuos, evaluamos diferentes estrategias de introgresión genética y sus posibles impactos en la población y en su genética. La reducción del riesgo de cuasi-extinción fue similar introduciendo 5 pumas cada 20 años o 15 pumas cada 10 años (44-59% vs. 40-58%), pero la primera opción resulta más económica ($200,000 en 100 años) que la segunda ($1,2000,000 en 100 años). Introducir más hembras en cada intento de introgresión no produjo beneficios adicionales. El impacto positivo del proyecto de introgresión genética persiste en la población de panteras veinte años después de su implementación. Recomendamos a los gestores que consideren repetir la in-trogresión genética introduciendo 5-10 individuos de otras poblaciones de puma cada 20-40 años. Adicionalmente, recomendamos que se continúe con la recopilación de datos, lo que es crucial para poder estimar y monitorizar la supervivencia de cachorros, adultos y subadultos. Estos parámetros son los más críticos para estimar la probabilidad y el periodo de cuasi-extinción, según se demostró con el análisis de sensibilidad. Se debe continuar con la mon-itorización de la población a largo plazo, lo que permitirá adaptar las estrategias de manejo según sea necesario, a la vez que recopilar información esencial para evaluar la salud demográfica de la población. Siguiendo estas re-comendaciones, las perspectivas de recuperación de las panteras, mejorarán.
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Cougar (Puma concolor) hunting has been classified typically as either selective-hunting with the aid of dogs or nonselective-hunting without dogs; this is based on the assumption that hunters using dogs to tree cougars can better identify sex of cougars prior to harvest. Subsequent to hunt activity, 94% of all wildlife agencies that allow cougar hunting have mandatory inspections where sex is identified and recorded by agency staff. To test the ability of hunters and agency staff in Washington, USA, to correctly identify sex of cougars in the field, laboratory analysis of DNA from tissue samples collected by experienced hound handlers using biopsy darts and collected during staff inspection of mortalities, respectively, was compared with visual identification and used to determine error rates. The sex assigned by dog hunters in the field matched sex from DNA analysis 70% of the time (n = 159); correct identification varied between 57% and 88%/year. The sex identified by agency staff during inspection of mortalities matched DNA analysis 87% of the time (n = 1,329); correct identification varied between 71% and 90%/year. Because sex misclassification has the potential to alter intended harvest as well as assessing success of management prescriptions, agencies may want to initiate education programs internally and outside their agency. The majority of states and provinces already have mandatory inspections; therefore, agencies would benefit from initiating DNA collection during mandatory inspections to identify error rates of sex identification by staff within their jurisdiction. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
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American black bears (Ursus americanus) historically inhabited every province and territory in Canada, all continental states in the United States (U.S.), and northern states of Mexico. We used BearsWhere?, an Internet mapping tool, to survey bear biologists in Canada, Mexico, and the U.S. and estimate the current range of black bears using 4 categories: primary range and secondary range (which together comprise total range), bear sighting locations outside range, and no bears reported. Primary and secondary ranges in 12 Canadian provinces and territories, 40 states in the U.S., and 6 states in Mexico totaled 10.5 million km2, representing 65–75% of the species’ historical range. Total bear range in Canada was 6.9 million km2, representing 95–100% of its historical range. Prince Edward Island was the only province with no bear range or sightings. Total range in the U.S. was 3.5 million km2, representing 45–60% of U.S. historical range. Respondents reported occasional sightings but no primary or secondary range in 6 U.S. states (IA, KS, NE, ND, OH, and SD), and bears were absent from the District of Columbia and the remaining 4 states (DE, HI, IL, and IN). Only primary range data were available in Mexico, consisting of approximately 99,000 km2 across portions of 6 states (Chihuahua, Coahuila, Durango, Nuevo Leon, Sonora, and Tamaulipas). Our ability to detect a change in bear range was limited, but notable expansion of primary range since the mid-1990s was confirmed in Virginia and North Carolina.
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Cougar (Puma concolor) management in Oregon is unique because hunting cougars with dogs was allowed through the 1994 hunting season, but thereafter Ballot Initiative Measure 18 prohibited the use of dogs to pursue cougars. Since 1995, hunting seasons have become increasingly longer with more tags sold. The effects of changing management structure on survival rates and causes of mortality of cougars are not well understood. We investigated survival and documented causes of mortality of radiocollared cougars at 3 study areas in Oregon from 1989 to 2011 under contrasting management strategies. The Catherine Creek (1989–1996) and Jackson Creek (1993–2002) studies overlapped the prohibition of hunting cougars with dogs, and the Wenaha, Sled Springs, and Mt. Emily (WSM) study was conducted from 2002 to 2011 when hunting cougars with dogs was illegal. Hunting mortality was the most common cause of death for sub-adult and adult cougars in Catherine Creek pre- (18 of 23 mortalities) and post-Measure 18 (1 of 2 mortalities) and WSM (24 of 53 mortalities) study areas in northeast Oregon. In contrast, natural mortality was the most common cause of death of sub-adults and adults at the Jackson Creek (25 of 38 mortalities) study area in southwest Oregon, but hunting mortality was most common prior to the passage of Measure 18 (3 of 3 mortalities). We estimated annual survival rates of cougars using known fate models in Program MARK. Annual survival rates of adult males were lowest at Catherine Creek prior to the passage of Measure 18 ( = 0.57; 95% CI = 0.39–0.73) and increased after Measure 18 ( = 0.86; 95% CI = 0.79–0.92), which were similar to those rates observed at Jackson Creek pre- and post-Measure 18 ( = 0.78; 95% CI = 0.65–0.88) and WSM ( = 0.82; 95% CI = 0.69–0.91). Regardless of hunting regulations, annual survival rates of adult females was similar among study areas (Catherine Creek pre- and post-Measure 18 [ = 0.86; 95% CI = 0.79–0.92]; Jackson Creek pre- and post-Measure 18 [ = 0.85; 95% CI = 0.77–0.91]; WSM [ = 0.85; 95% CI = 0.76–0.90]). At Jackson Creek pre- and post-Measure 18 and WSM, sub-adult males (1–3 years) had significantly lower survival than sub-adult females, but survival rates of males and females were similar by age 4 or 5 years. At WSM, survival declined for both sexes at older ages (8–13 years), but this decline was not observed at Jackson Creek pre- or post-Measure 18. The effect of increasing age on cougar survival should be considered when using survival rates to estimate population growth rates. We did not detect an effect of age on cougar survival at the Catherine Creek study area pre- or post-Measure 18, which we attributed to selective harvest of prime-aged, male cougars prior to the passage of Measure 18 and lack of mortality post-Measure 18. Managers should understand local sources of mortality when setting harvest regulations because sources of mortality may vary widely within and among jurisdictions, even if management practices are similar. Because of low hunter success rates when hunting cougars without dogs, survival rates of cougars managed under this hunting regime should be substantially higher than areas where use of dogs is legal. This suggests the ability of managers to effectively manipulate survival rates of cougars to meet population management objectives will be dependent on available hunting methods. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
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We examined Utahns' attitudes (n=901) toward use of recreational hunting to manage black bears (Ursus americanus) and cougars (Puma concolor), use of hounds to hunt these species, and the practice of bear baiting. Independent variables included urban versus rural residence, gender, educational attainment, age, duration of in-state residence, and stakeholder group classification. Most Utahns disapproved of the cougar and black bear management practices examined. Differences in responses were associated with sociodemographic characteristics and with participation in wildlife-related recreation. The following groups were less opposed to the selected practices than their counterparts: rural residents, men, those with lower levels of education, longtime residents, younger respondents, and hunters. Survey analyses can help wildlife managers identify areas of controversy where public involvement and educational efforts might be prescribed.
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Estimation of animal density is fundamental to ecology, and ecologists often pursue density estimates using grids of detectors (e.g., cameras, live traps, hair snags) to sample animals at a study site. However, under such a framework, reliable estimates can be difficult to obtain because animals move on and off of the site during the sampling session (i.e., the site is not closed geographically). Generally, practitioners address lack of geographic closure by inflating the area sampled by the detectors based on the mean distance individuals moved between trapping events or invoking hierarchical models in which animal density is assumed to be a spatial point process, and detection is modeled as a declining function of distance to a detector. We provide an alternative in which lack of geographic closure is sampled directly using telemetry, and this auxiliary information is used to compute estimates of density based on a modified Huggins closed-capture estimator. Contrary to other approaches, this method is free from assumptions regarding the distribution and movement of animals on the landscape, the stationarity of their home ranges, and biases induced by abnormal movements in response to baited detectors. The estimator is freely available in Program MARK.
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Wildlife managers require reliable information on factors that influence animal populations to develop successful management programs, including the puma (Puma concolor), in western North America. As puma populations have recovered in recent decades because of restrictions on human‐caused mortality, managers need a clear understanding of the factors that limit or regulate puma populations and how those factors might be manipulated to achieve management objectives, including sustaining puma and other wildlife populations, providing hunting opportunity, and reducing puma interactions with people. I synthesized technical literature on puma populations, behavior, and relationships with prey that have contributed to hypotheses on puma population limitation and regulation. Current hypotheses on puma population limitation include the social limitation hypothesis and the food limitation hypothesis. Associated with each of those are 2 hypotheses on puma population regulation: the social regulation hypothesis and the competition regulation hypothesis. I organize the biological and ecological attributes of pumas reported in the literature under these hypotheses. I discuss the validity of these hypotheses based on the limits of the research associated with the hypotheses and the evolutionary processes theoretically underlying them. I review the management predictions as framed by these hypotheses as they pertain to puma hunting, puma‐prey relationships, and human‐puma interactions. The food limitation and competition regulation hypotheses explain more phenomena associated with puma and likely would guide more successful management outcomes. © 2019 The Wildlife Society. Two main theories have been proposed for natural limitation and regulation of puma populations: the social limitation and social regulation hypotheses, and the food limitation and competition regulation hypotheses. Overall, the food limitation and competition regulation hypotheses are the more parsimonious explanations for biological and ecological phenomena associated with pumas, and likely better guide efforts in conserving pumas, and managing puma hunting, puma predation on prey populations of concern, and human‐puma interactions.
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From 2014 to 2016, in the Front Range of Colorado, USA, we assessed noninvasive approaches to sampling cougar (Puma concolor) populations in an attempt to provide a new method that would be less field intensive, less expensive, and could be applied over large spatial extents compared with current methods. We assessed the use of predator calls to lure cougars to a site with remote camera traps for detection and also evaluated hair snags at sites to noninvasively identify individual animals. Predator calls effectively attracted cougars to specific sites with an average of 82 unique photographic detections of cougars per survey year (0.03 detections/trap‐night). However, obtaining hair samples from these animals was less effective because animals did not always pass through hair snags and ability to uniquely identify individuals by genotype was poor. We evaluated different approaches to estimating cougar density and found mark–resight to be a viable option in our study system. Mark–resight density estimate after correcting for partial use of the sampling area by cougars was 4.1 cougars/100 km2 (95% CI = 2.4, 5.8). Our results indicate that combining methods of noninvasive genetic sampling and auditory calls to monitor cougar populations can provide reliable density estimates over large geographic areas and areas with significant amounts of inaccessible private lands. © 2019 The Wildlife Society. Currently Colorado, USA, does not have any current estimates of cougar population density, so this study was conducted to develop reliable techniques to sample cougar populations and produce a reliable density estimate. We found, using predator calls and trail cameras in a mark‐resight framework, cougar density was 4.1 cougars/100 km2 in a lightly hunted cougar population in the Front Range of Colorado.
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Females valued wild animals as objects of affection and expressed considerable concern regarding the consumptive exploitation of wildlife. Males were far more knowledgeable and less fearful of wildlife and more inclined to value animals for practical and recreational reasons. Efforts to broaden the scope and effectiveness of wildlife management should consider and understand the influence of gender. -Authors
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Expansion by wolf (Canis lupus) populations in the western United States creates new opportunities and challenges for researching and managing large mammal predator-prey systems. Therefore, we compared patterns of prey selection between wolves and cougars (Puma concolor) to ascertain the effects of multiple predators on prey and on each other. Because of differences in hunting techniques, we predicted that wolves would kill more vulnerable classes of prey than cougars. Our results did not support this prediction. White-tailed deer (Odocoileus virginianus) composed the greatest proportion of wolf (0.83) and cougar kills (0.87), but elk (Cervus elaphus) and moose (Alces alces) composed a larger proportion of wolf (0.14, 0.03, respectively) than cougar (0.06, 0.02, respectively) kills. Wolves and cougars selected older and younger deer and elk than did hunters. Cougars killed relatively more bull elk (0.74) than did wolves (0.48). Male deer killed by cougars had shorter diastema lengths than did male deer killed by wolves (P = 0.02). Pack hunting by wolves and dense stalking cover may have partially explained the failure to support predictions of the coursing versus stalking dichotomy. Wolves and cougars may be exhibiting exploitation and interference competition that is affecting each others' behavior and dynamics, and that of their prey.
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The estimation of survival distributions for animals which are radio-tagged is an important current problem for animal ecologists. Allowance must be made for censoring due to radio failure, radio loss, emigration from the study area and animals surviving p88l. :~the end of the study period. First we show that the Kaplan-Meier .procedure wid~ly used in medical and engineering studies can be applied to this problem. An example using some quail data is given for illustration. As radios maItunction -or are lost, new radio-tagged animals have to be added to the study. We show how this modification can easily be incorpor~.ted inf.<? the basic Kaplan-Meier procedure. Another example using quail data is used to illustrate the extension. We also show how the log rank test commonly used to compare two survival distributions can be generalized to allow for additions. Simple computer programs which can be run on a PC are available from the authors.
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One of the basic assumptions central to the analysis of capture-recapture experiments is that all marked animals remain in the population under study for the duration of the sampling, or if they migrate out of the population they do so permanently. K. P. Burnham [in J.-D. Lebreton and P. M. North (eds.), Marked Individuals in the Study of Bird Populations, 199-213 (1993)], W. L. Kendall and J. D. Nichols [J. Appl. Stat. 22, 751-762 (1995)], and W. L. Kendall, J. D. Nichols and J. E. Hines (in press) showed that completely random temporary emigration influences only estimates of the probability of capture, these now estimating the product of the temporary emigration rate and the conditional probability of capture given the animal remains in the population. Estimates of abundance or survival that refer to the entire population, including the temporary emigrants, remain unaffected. W. L. Kendall et al. (in press) further showed that K. H. Pollock’s [J. Wildlife Manage 46, 757-760 (1982)] robust design could be used to estimate the temporary emigration rate when the population ws assumed closed during the secondary samples. We generalize this result to allow animals to enter and leave the population during the secondary samples. We apply the results to a study of Grey Seals and perform simulation experiments to assess the robustness of our estimator to errors in field identification of brands and other violations of our assumptions.
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Cougar (Puma concolor) management has been hindered by inability to identify population trends. We documented changes in sex and age of harvested cougars during an experimentally induced reduction in population size and subsequent recovery to better understand the relationship between sex-age composition and population trend in exploited populations. The cougar population in the Snowy Range, southeast Wyoming, was reduced by increased harvest (treatment phase) from 58 independent cougars (>1 year old) (90% C***l = 36–81) in the autumn of 1998 to 20 by the spring of 2000 (mean exploitation rate = 43%) and then increased to 46 by spring 2003 following 3 years of reduced harvests (mean exploitation rate = 18%). Pretreatment harvest composition was 63% subadults (1.0–2.5 years old), 23% adult males, and 14% adult females (2 seasons; n = 22). A reduction in subadult harvest, an initial increase followed by a reduction in adult male harvest, and a steady increase in adult female harvest characterized harvest composition trends during the treatment phase. Harvest composition was similar at high and low densities when harvest was light, but proportion of harvested subadult males increased at low density as they replaced adult males removed during the treatment period (high harvest). While sex ratio of harvested cougars alone appears of limited value in identifying population change, when combined with age class the 2 appear to provide an index to population change. Composition of the harvest can be applied to adaptively manage cougar populations where adequate sex and age data are collected from harvested animals.
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Mountain lions (Puma concolor) are widely hunted for recreation, population control, and to reduce conflict with humans, but much is still unknown regarding the effects of harvest on mountain lion population dynamics. Whether human hunting mortality on mountain lions is additive or compensatory is debated. Our primary objective was to investigate population effects of harvest on mountain lions. We addressed this objective with a management experiment of 3 years of intensive harvest followed by a 6-year recovery period. In December 2000, after 3 years of hunting, approximately 66% of a single game management unit within the Blackfoot River watershed in Montana was closed to lion hunting, effectively creating a refuge representing approximately 12% (915 km2) of the total study area (7,908 km2). Hunting continued in the remainder of the study area, but harvest levels declined from approximately 9/1,000 km2 in 2001 to 2/1,000 km2 in 2006 as a result of the protected area and reduced quotas outside. We radiocollared 117 mountain lions from 1998 to 2006. We recorded known fates for 63 animals, and right-censored the remainder. Although hunting directly reduced survival, parameters such as litter size, birth interval, maternity, age at dispersal, and age of first reproduction were not significantly affected. Sensitivity analysis showed that female survival and maternity were most influential on population growth. Life-stage simulation analysis (LSA) demonstrated the effect of hunting on the population dynamics of mountain lions. In our non-hunted population, reproduction (kitten survival and maternity) accounted for approximately 62% of the variation in growth rate, whereas adult female survival accounted for 30%. Hunting reversed this, increasing the reliance of population growth on adult female survival (45% of the variation in population growth), and away from reproduction (12%). Our research showed that harvest at the levels implemented in this study did not affect population productivity (i.e., maternity), but had an additive effect on mountain lion mortality, and therefore population growth. Through harvest, wildlife managers have the ability to control mountain lion populations. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Article
Cougar (Puma concolor) populations have expanded in many western areas of the United States. The Black Hills cougar population naturally recolonized the area and cohabitates within an ecosystem heavily dissected by roads and human activity. Assessing mortality characteristics and determining survival of cougar populations is critical for managing and conserving this species. Our objectives were to assess cause-specific mortality and estimate survival of the Black Hills cougar population, in addition to assessing annual mortality through ancillary opportunistic methods. We captured and radiocollared cougars during 1999–2005 to assess survival and cause-specific mortality. In addition to cause-specific mortality, we also documented all known cougar mortality opportunistically throughout the study area in conjunction with the South Dakota Department of Game, Fish and Parks. We captured 31 independent-aged cougars (n = 12 M, 19 F) for analyses. We opportunistically documented 85 mortality events of cougars in South Dakota during 1998–2005. Despite protection from hunting during our study, 61.5% of mortality was human-induced, in contrast to other studies of unhunted cougar populations that generally attribute natural mortality as the primary mortality source. Male and female cougars exhibited relatively high survival through the course of the study; however, low sample sizes precluded rigorous comparisons of annual survival rates between sex and age cohorts. Proportionally, the largest contributors to cougar mortality were lethal removal by the state agency (e.g., depredation, human-safety concerns) and vehicular trauma. Continued assessment of cause-specific mortality and survival will be useful for evaluating effects of future manipulations of this population. The potential effects of human-caused cougar mortalities should be considered when evaluating management strategies for cougars in landscapes with high propensity for human–cougar interactions.