Population densities of curassows, guans, and chachalacas (Cracidae): Effects of body size, habitat, season, and hunting

Kattan, Gustavo H.; Muñoz, Marcia C.; Kikuchi, David W.

doi:10.1650/condor-15-51.1

Cited by 30 publications

(34 citation statements)

References 44 publications

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“…We also found that the decrease in forest cover negatively affected occupancy by Bare-faced Curassows along the rivers. Most species of cracids are threatened by human activities, including hunting (Barrio 2011, Kattan et al 2015, as well as by forest loss and fragmentation (Melo-Vásquez et al 2008, Thornton et al 2012, Pardo et al 2017). However, Kattan et al (2015) suggest that hunting is the main threat to cracids.…”

Section: Discussionmentioning

confidence: 99%

Determining the factors that influence the occurrence of Bare-faced Curassows (Crax fasciolata) in Humid Chaco, northern Argentina

Zalazar¹,

Benitez²,

Giacomo³

2018

ACE

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2018. Determining the factors that influence the occurrence of Bare-faced Curassows (Crax fasciolata) in Humid Chaco, northern Argentina. Avian Conservation and Ecology 13(2):1. https://doi. ABSTRACT. Identifying factors that determine the spatial distribution of threatened species is key to ensuring their conservation. The Bare-faced Curassow (Crax fasciolata) is a globally threatened bird that is categorized as Vulnerable, and its populations are declining in the gallery forests of the Humid Chaco. To evaluate the effect of human activities and environmental characteristics on the occupancy of Bare-faced Curassows, we sampled 48 sites along two rivers in northern Argentina. Bare-faced Curassows were recorded in 46% of the sites visited. The anthropic activities were identified as hunting pressure, selective logging of timber, and livestock production. Hunting and logging were positively associated with each other, and in turn, negatively related to village distance. We evaluated 17 occupancy models using six predictive variables. Occupancy by the Bare-faced Curassow was positively influenced by the distance to the nearest village and by forest cover. To a lesser extent, occupancy was also positively associated with an increase in availability of trees with fleshy fruits and with river course length. Our results indicate that hunting pressure and selective logging are limited by the cost of access from populated areas. Thus, distance to the villages was a good indicator of these human activities along the gallery forests and could be used to determine the spatial distribution of the Bare-faced Curassow in its southern range. Our study highlights the value of using presence/absence surveys and occupancy models for assessing threats of threatened and elusive species such as cracids. Identification des facteurs qui influent sur l'occurrence du Hocco à face nue (Crax fasciolata) dans le Chaco humide du nord de l'ArgentineRÉSUMÉ. L'identification des facteurs qui influent le plus sur la répartition spatiale d'espèces menacées est fondamentale si l'on veut assurer leur conservation. Le Hocco à face nue (Crax fasciolata) est un oiseau menacé à l'échelle planétaire et classé comme « vulnérable »; ses populations sont en diminution dans les forêts-galeries du Chaco humide. Pour évaluer l'effet des activités humaines et des caractéristiques environnementales sur la présence des Hoccos à face nue, nous avons échantillonnés 48 sites le long de deux rivières dans le nord de l'Argentine. Des Hoccos à face nue ont été trouvés dans 46 % des sites visités. Les activités d'origine anthropique qui ont été identifiées sont la pression de chasse, la coupe sélective de bois et l'élevage de bétail. La chasse et la coupe de bois étaient positivement associées l'une à l'autre, mais négativement liées à la distance d'un village. Nous avons évalué 17 modèles de présence au moyen de six variables explicatives. La présence du Hocco à face nue était positivement associée avec la distance au village le plus proche et le couvert forestier. Dan...

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Section: Discussionmentioning

confidence: 99%

Determining the factors that influence the occurrence of Bare-faced Curassows (Crax fasciolata) in Humid Chaco, northern Argentina

Zalazar¹,

Benitez²,

Giacomo³

2018

ACE

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“…The Guianan red howler monkey, black spider monkey and Guianan brown capuchin (which have high predicted detection probabilities based on our results) are consequently less abundant in hunted areas in northern French Guiana (de Thoisy et al 2005). Large species such as the Black Curassow, Grey-winged Trumpeter, and Marail Guan (which have high detection probabilities) are the first to be impacted by hunting in French Guiana (de Thoisy et al 2010, Denis et al 2016 or in Central and South America (Peres 2000, Kattan et al 2015. These two species have the lowest reproductive rates among the monkeys, but have the highest detection probabilities; consequently, these species are especially vulnerable to hunting.…”

Section: Discussionmentioning

confidence: 99%

“…3b) reinforce the idea that the species detection probability can be used as an indicator of species vulnerability to hunting and, thus, to risks of local extinctions. Large species such as the Black Curassow, Grey-winged Trumpeter, and Marail Guan (which have high detection probabilities) are the first to be impacted by hunting in French Guiana (de Thoisy et al 2010, Denis et al 2016 or in Central and South America (Peres 2000, Kattan et al 2015. As Bennett and Owens (1997) reported, the cracids family (mainly large species), which includes the curassows, guans, and chachalacas, is one of the most threatened bird families in the world.…”

Section: Discussionmentioning

confidence: 99%

Biological traits, rather than environment, shape detection curves of large vertebrates in neotropical rainforests

Denis

Richard‐Hansen

Brunaux

et al. 2017

Ecological Applications

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Line transect surveys are widely used in Neotropical rainforests to estimate the population abundance of medium- and large-sized vertebrates. The use of indices such as encounter rate has been criticized because the probability of animal detection may fluctuate due to the heterogeneity of environmental conditions among sites. In addition, the morphological and behavioral characteristics (biological traits) of species affect their detectability. In this study, we compared the extent to which environmental conditions and species' biological traits bias abundance estimates in terra firme rainforests in French Guiana. The selected environmental conditions included both physical conditions and forest structure covariates, while the selected biological traits included the morphological and behavioral characteristics of species. We used the distance sampling method to model the detection probability as an explicit function of environmental conditions and biological traits and implemented a model selection process to determine the relative importance of each group of covariates. Biological traits contributed to the variability of animal detectability more than environmental conditions, which had only a marginal effect. Detectability was best for large animals with uniform or disruptive markings that live in groups in the canopy top. Detectability was worst for small, solitary, terrestrial animals with mottled markings. In the terra firme rainforests that represent ~80% of the Amazonia and Guianas regions, our findings support the use of relative indices such as the encounter rate to compare population abundance between sites in species-specific studies. Even though terra firme rainforests may appear similar between regions of Amazonia and the Guianas, comparability must be ensured, especially in forests disturbed by human activity. The detection probability can be used as an indicator of species' vulnerability to hunting and, thus, to the risk of local extinction. Only a few biological trait covariates are required to correctly estimate the detectability of the majority of medium- and large-sized vertebrates. Thus, a biological trait model could be useful in predicting the detection probabilities of rare, uncommon, or localized species for which few data are available to fit the detection function.

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“…This approach is essential to understand the population trends of Neotropical birds, particularly of those endemic to montane ranges, which exhibit low densities (Jankowski and Rabenold, 2007). However, the population estimates of endangered bird species are still scarce (Kanegae, 2012) or mainly focused on large frugivorous (Kattan et al, 2014(Kattan et al, , 2015Denis et al, 2016;González-García et al, 2017;Quiñónez-Guzmán et al, 2017). In other cases, the few available estimations are not corrected by differences in sampling effort or habitat (e.g.…”

Section: Introductionmentioning

confidence: 99%

Multinomial-Poisson mixture models reveal unexpected higher density estimates of an Andean threatened bird

Gómez-Hoyos

Marín-Gómez²,

Ylc

2018

Preprint

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Multinomial-Poisson mixture models reveal unexpected higher density estimates of an Andean threatened bird. Distance sampling and repeated counts are important tools to estimate population density of birds with low detectability. Here we use model based approach to assess the population density of a threatened bird, the Multicolored Tanager (Chlorochrysa nitidissima). We conducted 144 fixed point counts samplings to record all the individuals of the Multicolored Tanager detected by visual and aural observations from different habitats (forest edge, mature, secondary, and riparian forest), during four months in an Important Bird Area of Central Andes of Colombia. We used spatially replicated counts, distance sampling, and multinomial-Poisson mixture models to estimate the population density of the Multicolored Tanager. Accumulated sampling effort was of 576 repetitions in 144 point counts with 96 h of observation. The Multinomial-Poisson mixture model showed the best fit due low variance of density estimations in comparison to the conventional distance sampling and the spatially replicated counts. Results of this model evidenced a remarkable higher density estimates (1.3 -2.05 individuals/ha) of the Multicolored Tanager, particularly in mature and secondary forest, as a result of detection

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Population densities of curassows, guans, and chachalacas (Cracidae): Effects of body size, habitat, season, and hunting

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 30 publications

References 44 publications

Determining the factors that influence the occurrence of Bare-faced Curassows (Crax fasciolata) in Humid Chaco, northern Argentina

Determining the factors that influence the occurrence of Bare-faced Curassows (Crax fasciolata) in Humid Chaco, northern Argentina

Biological traits, rather than environment, shape detection curves of large vertebrates in neotropical rainforests

Multinomial-Poisson mixture models reveal unexpected higher density estimates of an Andean threatened bird

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