Resumen: 1) The mangrove study site is low in plant diversity and species richness and follows a typical pattern for mangrove forest communities. 2) The mangrove howler population in Arroyo Polo is stable, despite their low-diversity habitat and limited diet. Group sizes, group demographics, and population density are all within the normal range reported for black howlers. 3) The mangrove howler population in Arroyo Polo adjusts its behavior in response to food availability in general, feeding more frequently and engaging in more affiliative social behavior when seasonal resources are available, and generally resting more during some months when only leaves are available. The low aggression rate in this population, both within and between groups, is indicative of low competition for resources when it comes to either food or mating opportunities. 4) The mangrove howlers rely heavily on flowers and seeds during the dry season, much more so than is reported for other black howler populations and other howler species. Consumption of leaves was within the range for howlers in general, but was slightly lower than is reported for black howlers at several sites. The consumption of fleshy or propagule fruits in the mangrove was non-existent and thus was significantly lower than fruit consumption for other howlers. The howlers did not incorporate any novel foods into their diets. 5) The mangrove howlers favored seasonal items when they were available and may have been influenced by protein to fiber ratios. In the case of leaves, lower zinc and higher protein and mineral (Ca, Mg, S) levels seem to influence their selection by the howlers. Selection of foods with lower zinc and higher sulfate concentrations may be acting to keep copper levels in balance and preventing gastrointestinal distress, as is documented in Merck’s Verterinary Manual (2010). Flowers consumed by the howlers were high in protein and digestible nutrients. Fleshy and propagule fruits were not selected as food in the mangrove and were higher in lignin (a digestion deterrent), lower in sugars, protein, and Ca than other food items, in addition to being pithy in texture. 6) Within the mangrove site at Arroyo Polo, the howlers did consume young leaves and leaf buds from two true mangrove species. These leaves and leaf buds were significantly lower in available protein, sugars, and zinc than other leaves in the diet. Non-fiber carbohydrates were found in higher levels in these leaves. It is probable that low zinc and high carbohydrate concentrations in these food items were the reason they were selected by the howlers. 7) The diet of the mangrove howlers falls within the range of nutrient recommendations for nonhuman primates on an annual basis. There do seem to be seasonal deficiencies in some proximate and mineral elements, but these are only broad estimates and more detailed dietary data are needed to make a more accurate description. Despite this possible under or over estimation, it is apparent that howlers select high quality foods and are able to balance their nutrient intake, possibly selecting plants low in zinc and high in molybdenum to keep copper levels in check. 8) When compared with the plant foods of howlers in other habitats, the plant foods in the mangrove were different in many respects. Leaves in the mangrove were similar in P:F and sugars, yet higher in ash content than non-mangrove leaves. Although the percentage of ash in a sample contains the mineral concentrations, no differences were detected in leaf minerals among sites. Mangrove flowers were higher in P:F ratios and sugars than non-mangrove flowers, and were lower in water, available protein, and fiber. There were no significant mineral differences. Mangrove fruits were significantly lower in sugar and calcium than non-mangrove fruits. 9) Red mangrove (R. mangle) leaves and fruits in Arroyo Polo were double the amounts for crude protein and crude fat than this species in a Vietnam mangrove forest. This fact is a reflection of the differences that exist in similar habitats in different locations and confirms the necessity of site-specific studies and local environmental conditions. 10) Although there were significant differences in dietary components among conspecific populations and the nutritional quality of plants eaten, overall nutritional intake was not significantly different between the populations compared. This is an important part of dietary and conservation research that is often overlooked. In order to evaluate the suitability of potential habitats for monkeys (and other animals), it is most useful to take into consideration the plants that are available along with their nutritional content. In addition, toxins are important constituents in the selection of foods and should be included in such a study.

Resumen: This study examined the social and hormonal correlates of male reproductive strategies in two multimale-multifemale groups of black howler monkeys {Alouatia pigra) in Palenque National Park, Mexico during 14 months (June 2005 - July 2006). Reproductive strategies of this primate species include behavioral tactics that allow a male to establish himself in a bisexual group and subsequently to enhance his probability of gaining sexual access to females. Based on nine male migration events observed during this study, single males tended to join groups, whereas pairs of males took over groups and successfully evicted resident males. Despite heightened male agonsim during some of these immigration events, fecal glucocorticoid and androgen levels were not elevated in either immigrating males or males remaining in the group throughout these events. Resident males seldom engaged in agonistic and affiliative interactions with each other but frequently participated in mutual howling bouts, regardless of their past relationship and joint actions. Although no agonistic dominance hierarchies could be discerned among males, one resident male monopolized almost all mating opportunities. This male, here referred to as "central" male, spent significantly more time in close proximity to and engaged in affiliation at significantly higher rates with cycling females than "noncentral" males did, who had no or very few mating opportunities. Central males were largely responsible for maintaining these spatial associations and cultivating these social relationships. In addition, central males had significantly higher fecal androgen and glucocorticoid levels compared to noncentral males at all times, suggesting that their efforts of fostering social relationships with cycling females might represent a nonaggressive form of male-male competition over sexual access to females. Spatial associations were the strongest during the periovulatory periods of female ovarian cycles when most sexual interactions occurred. Concurrently, females approached and solicited sexual interactions with central males during their periovulatory periods, suggesting that females chose the central male as their closest neighbors and preferred mates, a reproductive strategy coinciding with that of central males. Black howler females, however, may occasionally choose to copulate with noncentral males or extragroup males, undermining the ability of central males to monopolize all reproductive opportunities.

Resumen: De acuerdo con lo esperado, el índice, velocidad y porcentaje final de germinación de semillas de guayaba extraídas de heces de mono aullador, muestran un efecto positivo en comparación con las semillas provenientes del fruto y las expuestas al digestor artificial. No se encontraron diferencias en cuando al índice, velocidad y porcentaje final germinación de las semillas del grupo control y las semillas expuestas al digestor artificial. Los resultados de este estudio indican que Alouatta pigra podría ser potencial dispersor de semillas de algunas de las plantas introducidas y que son explotadas por sus frutos en Balancán y de la importancia que tiene el paso por el tracto digestivo de los vertebrados en el éxito de germinación de las semillas. Aun cuando Psidium guajava no es una especie predominante en esta región, la disponibilidad de su fruto puede representar un recurso alimenticio extra para estos primates que habitan un parche de bosque con vegetación limitada La permanencia de los monos aulladores negros en los hábitat fragmentados es de gran importancia. Las características del tracto digestivo del genero Alouatta así como los resultados obtenidos en este estudio sugieren que estos podrían incrementar el éxito germinativo de las semillas que consumen.

Resumen: En este estudio se realizó un análisis socioeconómico, político y ambiental de cuatro ejidos de la Sierra de Santa Marta, Reserva de Biosfera Los Tuxtlas (RBLT), con la finalidad de identificar los factores que han influido en el estado de conservación de los primates y su hábitat. Se evaluó el estado actual de las poblaciones de primates, la disponibilidad de hábitat y tasas de deforestación, así como la percepción de los pobladores locales acerca de la problemática en la región y el funcionamiento de la RBLT. Se encontró un número de individuos de ambas especies de primates similar al reportado en años anteriores. Los fragmentos actualmente ocupados por primates presentan porcentajes mayores de deforestación que de regeneración, indicando cuán amenazado está el hábitat de los primates en esta zona. La actividad económica principal en los ejidos ha sido la ganadería extensiva, con 52% de la superficie total dedicada a potreros. De 1986?2007 disminuyeron las tasas de deforestación de 1.5% a 0.4% anual. Los eventos que mayor impacto han tenido en la conformación del paisaje natural y social actual en la zona de estudio han sido las políticas nacionales de colonización y reparto agrario (1940?1980), el control y poder político de grupos ganaderos (1970?1980), la caída de los precios de productos del campo (1983 y 1989) y las políticas nacionales para el desarrollo agropecuario (1993?a la fecha). El modelo de metabolismo social elaborado muestra que, la forma de aprovechamiento de los recursos naturales ha resultado en una disminución en los flujos de retorno, obligando a los pobladores locales a la dependencia de insumos externos para poder subsistir. En lo relativo a los mecanismos de gestión de la RBLT se encontró que la carencia de un programa de manejo oficial, la insuficiencia de personal, la falta de presupuesto y la casi nula coordinación intersectorial han limitado la conservación de los primates y su hábitat. Las tendencias reconocidas para la zona de estudio, sugieren un escenario futuro incierto, tanto para las poblaciones de primates, como para los habitantes locales y los gestores de la RBLT. La viabilidad y conservación de las poblaciones de primates en esta zona está ligada a las decisiones políticas que se toman en los distintos niveles de gobierno, a través de los sistemas productivos adoptados por las comunidades locales y de los mecanismos de gestión de la RBLT. Es necesario que la dirección de la RBLT busque mecanismos más efectivos para integrar a las poblaciones locales y de esta manera facilitar la implementación de estrategias conservacionistas dirigidas a revertir los patrones y tendencias de transformación del paisaje.

Resumen: El objetivo principal de este trabajo es evaluar el éxito de la translocación de un grupo de monos aulladores (Alouatta palliata) a un fragmento de uso agroforestal. De esta manera se pretende comprobar la compatibilidad entre la producción económica y la conservación de especies amenazadas por la pérdida de hábitats. Así mismo este estudio pretende contribuir al mejor conocimiento de la translocación como medida de conservación. Para determinar el éxito de la translocación se realizó una búsqueda bibliográfica de los casos de translocación reportados hasta la fecha y se seleccionaron aquellos indicativos de éxito que se ajustaran a la especie de estudio. Los indicativos seleccionados se analizaron y compararon con otros estudios de la especie y específicamente con el estudio de Shedden (2007). Los indicativos seleccionados fueron los siguientes: ? El PDA. ? Las preferencias alimenticias: especies utilizadas y partes consumidas. ? El ámbito hogareño y los cambios en el área de ocupación. ? Conducta social. ? Demografía ? Otros aspectos: Seguridad, impacto humano y competencia alimenticia. Valores de estos indicativos que se ajusten al valor reportado para la especie se consideraron reflejo de buena salud del grupo, debido a que de ser así el grupo no presentaría problemas evidentes. Así mismo se evaluaron los índices seleccionados con la intención de establecer un modo de evaluación de aplicación general para las translocaciones de A. palliata.