Alfredo D Cuarón | University of Cambridge (original) (raw)

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Papers by Alfredo D Cuarón

Animals' responses to potentially threatening factors can provide important information for their... more Animals' responses to potentially threatening factors can provide important information for their conservation. Group size and human presence are potentially threatening factors to primates inhabiting small reserves used for recreation. We tested these hypotheses by evaluating behavioral and physiological responses in two groups of mantled howler monkeys (Alouatta palliata mexicana) at the " Centro Ecológico y Recreativo El Zapotal " , a recreational forest reserve and zoo located in the Mexican state of Chiapas. Both groups presented fission‐fusion dynamics, splitting into foraging subgroups which varied in size among, but not within days. Neither subgroup size nor number of people had an effect on fecal cortisol. Out of 16 behavioral response variables tested, the studied factors had effects on six: four were affected by subgroup size and two were affected by number of people. With increasing subgroup size, monkeys increased daily path lengths, rested less, increased foraging effort, and used more plant individuals for feeding. As the number of people increased, monkeys spent more time in lower‐quality habitat, and less time engaged in social interactions. Although fecal cortisol levels were not affected by the factors studied, one of the monkey groups had almost twice the level of cortisol compared to the other group. The group with higher cortisol levels also spent significantly more time in the lower‐quality habitat, compared to the other group. Our results suggest that particular behavioral adjustments might allow howler monkeys at El Zapotal to avoid physiological stress due to subgroup size and number of people. However, the fact that one of the monkey groups is showing increased cortisol levels may be interpreted as a warning sign, indicating that an adjustment threshold is being reached, at least for part of the howler monkey population in this forest fragment. Am.

Biodiversity and Conservation, 2010

Biodiversity and Conservation, 2000

Endangered species lists are important tools in conservation. It is essential that these lists be... more Endangered species lists are important tools in conservation. It is essential that these lists be prepared using categorization systems that objectively assess species extinction risk. To determine which threatened species categorization system is the most appropriate and the virtues and limitations of systems used on the American continent, we evaluated 25 categorization systems from 20 countries. These systems included examples of international lists, most national systems used on the American continent, and some systems independently proposed by academics. We based our assessment on 15 characteristics that categorization systems should have, in terms of categories, criteria, and other relevant issues, in order to evaluate species conservation status objectively. Of all evaluated systems, the current World Conservation Union system is the most suitable for assessing species extinction risk. Most categorization systems, but particularly national systems, have serious deficiencies and need to be improved substantially. We recommend governments use three types of lists: (1) threatened species lists constructed following a sound categorization system, (2) lists of species of conservation priority, and (3) lists that serve as normative tools (e.g., Convention on International Trade in Endangered Species of Wild Fauna and Flora). Additionally, the information used to categorize species should be explicit and available to the public. To make the most of threatened species lists in conservation, it is imperative that all countries use the same categorization system. Resumen: Las listas de especies amenazadas son importantes herramientas para la conservación. Es esencial que estas listas se preparen utilizando sistemas de categorización que evalúen objetivamente el riesgo de extinción de las especies. Para determinar qué sistema de categorización de especies amenazadas es el más apropiado y cuáles son las virtudes y limitaciones de los sistemas usados en el continente americano, evalua-mos 25 sistemas de categorización de 20 países. Estos sistemas incluyen ejemplos de listas internacionales, la mayoría de los sistemas nacionales usados en el continente americano, y algunos sistemas propuestos independientemente por académicos. Basamos nuestra evaluación en 15 características que los sistemas de categorización deben tener en términos de las categorías, criterios y otros temas relevantes, para evaluar objetivamente la situación de conservación de las especies. De los sistemas evaluados, el actual sistema de la Unión Mundial para la Conservación es el más apropiado para determinar el riesgo de extinción de las especies. La mayoría de los sistemas de categorización, pero especialmente los sistemas nacionales, tienen serias deficiencias y deben ser mejorados substancialmente. Recomendamos que los gobiernos usen tres tipos de listados: (1) listas de especies amenazadas preparadas usando un sistema de categorización adecuado; (2) listas de especies prioritarias para la conservación; y (3) listas que sirven como herramientas normativas (v.gr., Convención sobre el Comercio Internacional de Especies Amenazadas de Fauna y Flora Silvestres). Adicionalmente, la información usada para categorizar a las especies debe ser explícita y estar disponible ‡Address correspondence to A. D. Cuarón, email cuaron@oikos.unam.mx & cuaron@fmvz.unam.mx Paper

It is necessary to assess whether the management of protected areas is achieving the objectives s... more It is necessary to assess whether the management of protected areas is achieving the objectives set for them. In particular, changes and trends in wildlife populations should be documented. We compared the 1990 abundance of mammals in two Costa Rican protected areas, Corcovado National Park (CNP) and Golfo Dulce Forest Reserve (GDFR), with similar environmental characteristics but different hunting restrictions and levels of protection. We also monitored the abundance of mammals in CNP over a 4-year period. We also devised an inexpensive method of monitoring tropical rainforest mammal populations in a timely and efficient manner. The method is based on the use of mammal track records and arboreal mammal sightings and requires little effort. With this method 20 mammal species were recorded at CNP and 15 at GDFR. Species were consistently less abundant in GDFR than in CNP, principally those species preferred by hunters. Species were grouped according to whether or not they are used as food and whether they are locally or globally threatened or not threatened. The abundance of all these groups of species in GDFR was 6–28% the abundance in CNP. During 1990–1994, overall mammal abundance in CNP remained relatively stable, but there was considerable variability among species. As a group, both species used for food and globally threatened species declined in abundance during that period in CNP. The abundance of all groups of species declined from 1992 to 1994, coinciding with a reduction in hunting vigilance at CNP. Evidence suggests that the main factor differentiating the abundance of mammals in the two protected areas, and at CNP during the study period, was the level of hunting. Golfo Dulce Forest Reserve seems to be achieving only partial success in protecting wildlife, whereas Corcovado National Park seems to be considerably more effective, although not entirely successful. Monitoreo de Poblaciones de Mamíferos en Áreas Protegidas de Costa Rica con Diferentes Restricciones de Cacería Resumen: Es necesario evaluar si el manejo de áreas protegidas está cumpliendo con sus objetivos estableci-dos. En particular, se deben documentar los cambios y tendencias de las poblaciones de vida silvestre. En este estudio comparamos la abundancia de los mamíferos durante 1990 en dos áreas protegidas de Costa Rica con características ambientales semejantes, pero con diferentes restricciones en cuanto a la cacería y difer-entes niveles de protección: el Parque Nacional Corcovado (PNC) y la Reserva Forestal Golfo Dulce (RFGD). También comparamos la abundancia de los mamíferos en el PNC durante un periodo de cuatro años (1990-1994). Además desarrollamos un método barato, basado en el registro de huellas de mamíferos y en avista-mientos de mamíferos arborícolas. Este método requiere de poco esfuerzo y se puede usar para dar seguimiento a las poblaciones de mamíferos selváticos de manera rápida y eficiente. Con este método registramos la abun-dancia de 20 especies en el PNC y de 15 en la RFGD. Todas las especies fueron consistentemente menos abundan-tes en la RFGD que en el PNC, principalmente aquéllas preferidas por los cazadores. Agrupamos las especies según su uso o no como alimento y según si se consideran amenazadas o no, a nivel local o mundial. La

Cozumel Island in the Mexican Caribbean is inhabited by four carnivores, of which two, the Cozume... more Cozumel Island in the Mexican Caribbean is inhabited by four carnivores, of which two, the Cozumel coati Nasua nelsoni and pygmy raccoon Procyon pygmaeus, are endemic species. The taxonomic status of a third carnivore, a dwarf gray fox Urocyon cinereoargenteus, is undetermined, but may deserve subspecific or species-level recognition. The fourth species, the kinkajou (Potos flavus), may be a recent introduction. We review the status of these carnivores, report our field observations and results of line transect and trapping efforts, discuss current threats to these taxa, and make recommendations for 2 their conservation. A population density of 0.43 6 0.27 coatis / km , and a total island population size of 150 6 95 individuals, was estimated from 386 km of line transects in 1994–1995. Intensive trapping efforts (1479 trap-nights) in 2001 at multiple localities were unsuccessful. Pygmy raccoons were observed in the mangrove and coastal wetland areas of the island and in 2001 we captured 11 individuals with the same sampling efforts as for coatis (8.8 raccoons / 1000 trap-nights). The gray fox is also apparently very rare on the island. While a few observations of the animals have been made (1984, 1994 and 2001), no animals were seen along transects and none were trapped. The primary threats to the persistence of these taxa include introduced congeners, introduced predators, parasite and disease spill-over from exotic animals, habitat fragmentation, hunting and collection as pets, and hurricanes. We suggest that the Cozumel coati, pygmy raccoon, and the Cozumel population of the gray fox be considered as Critically Endangered according to the IUCN classification system. Current conservation actions focusing on Cozumel carnivores are extremely limited. We recommend eradication of introduced species, maintenance of habitat connectivity, ex situ conservation programs, explicit public policies on land-use and sustainable development, public awareness campaigns, and continuous scientific research and monitoring.

Land-cover changes translate into shifts in habitat available to wildlife species. I analyzed the... more Land-cover changes translate into shifts in habitat available to wildlife species. I analyzed the effects of land-cover changes on habitat availability for 54 mammal species in a 2.7 million-ha area in southern Mexico and northern Guatemala. I considered the regional variability of these changes and the effect of variation in management and development trends. Using cluster analysis, I grouped mammal species into assemblages with similar associations of land-cover type. Based on data from a remote-sensing, land-cover change analysis (1974–1986), I created simple linear Markov models for a heuristic tool to simulate land-cover changes over a 60-year period and to explore temporal trends of change in habitat availability for the mammal species. I used elasticity analyses to identify land-cover transition probabilities critical for these tra-jectories. Of the 12 land-cover classes considered, four dominated the area: grasslands, tropical secondary vegetation, tropical moist forests, and wetlands. Transition probabilities to and from these four land-cover types were key in determining the availability of habitat for mammals. Thus, the relatedness of mammal species to these land-cover types seems critical for their long-term persistence in the region. According to general simulated trends in fluctuation of habitat availability, I classified species into seven categories: (1) opportu-nistic and highly adaptable species, occupying most of the area; (2) opportunistic, human-commensal species, with restricted range in the study area; (3) species with stable and moderate habitat availability; (4) species with moderate but increasing habitat availability; (5) species with originally moderate but declining habitat availability; (6) species with already reduced and sharply declining habitat availability; and (7) species with declining habitat availability and a restricted range. Markovian trajectories suggest a declining trend of habitat availability for 32 species (59%). Land-cover change trends, however, were highly variable between the nine subregions. As a result, habitat availability for many species varied regionally. Likewise, changes in management and development policies and trends in the study area will lead to contrasting habitat availability for declining and increasing species, but not for the rest of the species. The approach I used is useful for (1) assessment of land-cover changes resulting from different development trends and management practices and (2) exploration of how changes may affect species habitat availability and survival perspectives. This examination can be accomplished for a substantial part of a biota and for entire regions, even in the context of limited information. Efectos de los Cambios en la Cobertura del Suelo sobre los Mamíferos de una Región Neotropical: una Estrategia de Modelaje Resumen: Los cambios en la cobertura del suelo se traducen en cambios de la disponibilidad del hábitat para las especies de vida silvestre. Analicé los efectos de los cambios en la cobertura del suelo sobre la dis-ponibilidad de hábitat para 54 especies de mamíferos en un área de 2.7 millones de hectáreas del sureste de México y el norte de Guatemala, tomando en cuenta la variabilidad regional de estos cambios y los efectos de la variación en el manejo y tendencias de desarrollo. Agrupé las especies de mamíferos en ensamblajes con similar asociación a los tipos de cobertura del suelo (i.e., requerimientos de hábitat), usando un análisis de cúmulos. Con base en datos de percepción remota de los cambios de la cobertura del suelo (1974-1986), elaboré modelos lineares simples de Markov usados como una herramienta heurística para simular cambios

Animals' responses to potentially threatening factors can provide important information for their... more Animals' responses to potentially threatening factors can provide important information for their conservation. Group size and human presence are potentially threatening factors to primates inhabiting small reserves used for recreation. We tested these hypotheses by evaluating behavioral and physiological responses in two groups of mantled howler monkeys (Alouatta palliata mexicana) at the " Centro Ecológico y Recreativo El Zapotal " , a recreational forest reserve and zoo located in the Mexican state of Chiapas. Both groups presented fission‐fusion dynamics, splitting into foraging subgroups which varied in size among, but not within days. Neither subgroup size nor number of people had an effect on fecal cortisol. Out of 16 behavioral response variables tested, the studied factors had effects on six: four were affected by subgroup size and two were affected by number of people. With increasing subgroup size, monkeys increased daily path lengths, rested less, increased foraging effort, and used more plant individuals for feeding. As the number of people increased, monkeys spent more time in lower‐quality habitat, and less time engaged in social interactions. Although fecal cortisol levels were not affected by the factors studied, one of the monkey groups had almost twice the level of cortisol compared to the other group. The group with higher cortisol levels also spent significantly more time in the lower‐quality habitat, compared to the other group. Our results suggest that particular behavioral adjustments might allow howler monkeys at El Zapotal to avoid physiological stress due to subgroup size and number of people. However, the fact that one of the monkey groups is showing increased cortisol levels may be interpreted as a warning sign, indicating that an adjustment threshold is being reached, at least for part of the howler monkey population in this forest fragment. Am.

Biodiversity and Conservation, 2010

Biodiversity and Conservation, 2000

Endangered species lists are important tools in conservation. It is essential that these lists be... more Endangered species lists are important tools in conservation. It is essential that these lists be prepared using categorization systems that objectively assess species extinction risk. To determine which threatened species categorization system is the most appropriate and the virtues and limitations of systems used on the American continent, we evaluated 25 categorization systems from 20 countries. These systems included examples of international lists, most national systems used on the American continent, and some systems independently proposed by academics. We based our assessment on 15 characteristics that categorization systems should have, in terms of categories, criteria, and other relevant issues, in order to evaluate species conservation status objectively. Of all evaluated systems, the current World Conservation Union system is the most suitable for assessing species extinction risk. Most categorization systems, but particularly national systems, have serious deficiencies and need to be improved substantially. We recommend governments use three types of lists: (1) threatened species lists constructed following a sound categorization system, (2) lists of species of conservation priority, and (3) lists that serve as normative tools (e.g., Convention on International Trade in Endangered Species of Wild Fauna and Flora). Additionally, the information used to categorize species should be explicit and available to the public. To make the most of threatened species lists in conservation, it is imperative that all countries use the same categorization system. Resumen: Las listas de especies amenazadas son importantes herramientas para la conservación. Es esencial que estas listas se preparen utilizando sistemas de categorización que evalúen objetivamente el riesgo de extinción de las especies. Para determinar qué sistema de categorización de especies amenazadas es el más apropiado y cuáles son las virtudes y limitaciones de los sistemas usados en el continente americano, evalua-mos 25 sistemas de categorización de 20 países. Estos sistemas incluyen ejemplos de listas internacionales, la mayoría de los sistemas nacionales usados en el continente americano, y algunos sistemas propuestos independientemente por académicos. Basamos nuestra evaluación en 15 características que los sistemas de categorización deben tener en términos de las categorías, criterios y otros temas relevantes, para evaluar objetivamente la situación de conservación de las especies. De los sistemas evaluados, el actual sistema de la Unión Mundial para la Conservación es el más apropiado para determinar el riesgo de extinción de las especies. La mayoría de los sistemas de categorización, pero especialmente los sistemas nacionales, tienen serias deficiencias y deben ser mejorados substancialmente. Recomendamos que los gobiernos usen tres tipos de listados: (1) listas de especies amenazadas preparadas usando un sistema de categorización adecuado; (2) listas de especies prioritarias para la conservación; y (3) listas que sirven como herramientas normativas (v.gr., Convención sobre el Comercio Internacional de Especies Amenazadas de Fauna y Flora Silvestres). Adicionalmente, la información usada para categorizar a las especies debe ser explícita y estar disponible ‡Address correspondence to A. D. Cuarón, email cuaron@oikos.unam.mx & cuaron@fmvz.unam.mx Paper

It is necessary to assess whether the management of protected areas is achieving the objectives s... more It is necessary to assess whether the management of protected areas is achieving the objectives set for them. In particular, changes and trends in wildlife populations should be documented. We compared the 1990 abundance of mammals in two Costa Rican protected areas, Corcovado National Park (CNP) and Golfo Dulce Forest Reserve (GDFR), with similar environmental characteristics but different hunting restrictions and levels of protection. We also monitored the abundance of mammals in CNP over a 4-year period. We also devised an inexpensive method of monitoring tropical rainforest mammal populations in a timely and efficient manner. The method is based on the use of mammal track records and arboreal mammal sightings and requires little effort. With this method 20 mammal species were recorded at CNP and 15 at GDFR. Species were consistently less abundant in GDFR than in CNP, principally those species preferred by hunters. Species were grouped according to whether or not they are used as food and whether they are locally or globally threatened or not threatened. The abundance of all these groups of species in GDFR was 6–28% the abundance in CNP. During 1990–1994, overall mammal abundance in CNP remained relatively stable, but there was considerable variability among species. As a group, both species used for food and globally threatened species declined in abundance during that period in CNP. The abundance of all groups of species declined from 1992 to 1994, coinciding with a reduction in hunting vigilance at CNP. Evidence suggests that the main factor differentiating the abundance of mammals in the two protected areas, and at CNP during the study period, was the level of hunting. Golfo Dulce Forest Reserve seems to be achieving only partial success in protecting wildlife, whereas Corcovado National Park seems to be considerably more effective, although not entirely successful. Monitoreo de Poblaciones de Mamíferos en Áreas Protegidas de Costa Rica con Diferentes Restricciones de Cacería Resumen: Es necesario evaluar si el manejo de áreas protegidas está cumpliendo con sus objetivos estableci-dos. En particular, se deben documentar los cambios y tendencias de las poblaciones de vida silvestre. En este estudio comparamos la abundancia de los mamíferos durante 1990 en dos áreas protegidas de Costa Rica con características ambientales semejantes, pero con diferentes restricciones en cuanto a la cacería y difer-entes niveles de protección: el Parque Nacional Corcovado (PNC) y la Reserva Forestal Golfo Dulce (RFGD). También comparamos la abundancia de los mamíferos en el PNC durante un periodo de cuatro años (1990-1994). Además desarrollamos un método barato, basado en el registro de huellas de mamíferos y en avista-mientos de mamíferos arborícolas. Este método requiere de poco esfuerzo y se puede usar para dar seguimiento a las poblaciones de mamíferos selváticos de manera rápida y eficiente. Con este método registramos la abun-dancia de 20 especies en el PNC y de 15 en la RFGD. Todas las especies fueron consistentemente menos abundan-tes en la RFGD que en el PNC, principalmente aquéllas preferidas por los cazadores. Agrupamos las especies según su uso o no como alimento y según si se consideran amenazadas o no, a nivel local o mundial. La

Cozumel Island in the Mexican Caribbean is inhabited by four carnivores, of which two, the Cozume... more Cozumel Island in the Mexican Caribbean is inhabited by four carnivores, of which two, the Cozumel coati Nasua nelsoni and pygmy raccoon Procyon pygmaeus, are endemic species. The taxonomic status of a third carnivore, a dwarf gray fox Urocyon cinereoargenteus, is undetermined, but may deserve subspecific or species-level recognition. The fourth species, the kinkajou (Potos flavus), may be a recent introduction. We review the status of these carnivores, report our field observations and results of line transect and trapping efforts, discuss current threats to these taxa, and make recommendations for 2 their conservation. A population density of 0.43 6 0.27 coatis / km , and a total island population size of 150 6 95 individuals, was estimated from 386 km of line transects in 1994–1995. Intensive trapping efforts (1479 trap-nights) in 2001 at multiple localities were unsuccessful. Pygmy raccoons were observed in the mangrove and coastal wetland areas of the island and in 2001 we captured 11 individuals with the same sampling efforts as for coatis (8.8 raccoons / 1000 trap-nights). The gray fox is also apparently very rare on the island. While a few observations of the animals have been made (1984, 1994 and 2001), no animals were seen along transects and none were trapped. The primary threats to the persistence of these taxa include introduced congeners, introduced predators, parasite and disease spill-over from exotic animals, habitat fragmentation, hunting and collection as pets, and hurricanes. We suggest that the Cozumel coati, pygmy raccoon, and the Cozumel population of the gray fox be considered as Critically Endangered according to the IUCN classification system. Current conservation actions focusing on Cozumel carnivores are extremely limited. We recommend eradication of introduced species, maintenance of habitat connectivity, ex situ conservation programs, explicit public policies on land-use and sustainable development, public awareness campaigns, and continuous scientific research and monitoring.

Land-cover changes translate into shifts in habitat available to wildlife species. I analyzed the... more Land-cover changes translate into shifts in habitat available to wildlife species. I analyzed the effects of land-cover changes on habitat availability for 54 mammal species in a 2.7 million-ha area in southern Mexico and northern Guatemala. I considered the regional variability of these changes and the effect of variation in management and development trends. Using cluster analysis, I grouped mammal species into assemblages with similar associations of land-cover type. Based on data from a remote-sensing, land-cover change analysis (1974–1986), I created simple linear Markov models for a heuristic tool to simulate land-cover changes over a 60-year period and to explore temporal trends of change in habitat availability for the mammal species. I used elasticity analyses to identify land-cover transition probabilities critical for these tra-jectories. Of the 12 land-cover classes considered, four dominated the area: grasslands, tropical secondary vegetation, tropical moist forests, and wetlands. Transition probabilities to and from these four land-cover types were key in determining the availability of habitat for mammals. Thus, the relatedness of mammal species to these land-cover types seems critical for their long-term persistence in the region. According to general simulated trends in fluctuation of habitat availability, I classified species into seven categories: (1) opportu-nistic and highly adaptable species, occupying most of the area; (2) opportunistic, human-commensal species, with restricted range in the study area; (3) species with stable and moderate habitat availability; (4) species with moderate but increasing habitat availability; (5) species with originally moderate but declining habitat availability; (6) species with already reduced and sharply declining habitat availability; and (7) species with declining habitat availability and a restricted range. Markovian trajectories suggest a declining trend of habitat availability for 32 species (59%). Land-cover change trends, however, were highly variable between the nine subregions. As a result, habitat availability for many species varied regionally. Likewise, changes in management and development policies and trends in the study area will lead to contrasting habitat availability for declining and increasing species, but not for the rest of the species. The approach I used is useful for (1) assessment of land-cover changes resulting from different development trends and management practices and (2) exploration of how changes may affect species habitat availability and survival perspectives. This examination can be accomplished for a substantial part of a biota and for entire regions, even in the context of limited information. Efectos de los Cambios en la Cobertura del Suelo sobre los Mamíferos de una Región Neotropical: una Estrategia de Modelaje Resumen: Los cambios en la cobertura del suelo se traducen en cambios de la disponibilidad del hábitat para las especies de vida silvestre. Analicé los efectos de los cambios en la cobertura del suelo sobre la dis-ponibilidad de hábitat para 54 especies de mamíferos en un área de 2.7 millones de hectáreas del sureste de México y el norte de Guatemala, tomando en cuenta la variabilidad regional de estos cambios y los efectos de la variación en el manejo y tendencias de desarrollo. Agrupé las especies de mamíferos en ensamblajes con similar asociación a los tipos de cobertura del suelo (i.e., requerimientos de hábitat), usando un análisis de cúmulos. Con base en datos de percepción remota de los cambios de la cobertura del suelo (1974-1986), elaboré modelos lineares simples de Markov usados como una herramienta heurística para simular cambios