White-nosed coatis (Nasua narica) are a potential reservoir of Trypanosoma cruzi and other potentially zoonotic pathogens in Monteverde, Costa Rica.

We studied white-nosed coatis (Nasua narica) in Monteverde, Costa Rica to evaluate their potential as a reservoir for the vector-borne zoonotic parasite Trypanosoma cruzi and other selected microorganisms. We live-trapped 20 coatis in July and August 2011 and tested them for T. cruzi by blood smear, molecular analysis of blood, culture of blood and anal gland secretions, and serology. Seven coatis (35%) were polymerase-chain-reaction-positive for T. cruzi and one coati was also culture positive. We did not detect T. cruzi in anal gland secretions. All coatis were positive for Mycoplasma and Babesia, but were negative for Baylisascaris, Anaplasma, Candidatus Neoehrlichia lotoris, Ehrlichia, Bartonella, and several apicomplexan parasites. The possible pathogenicity of T. cruzi, Babesia, and Mycoplasma in coatis and their transmission potential to humans and domestic animals warrants further investigation.

Seed predation by mammals in forest fragments in Monteverde, Costa Rica.

Few studies have evaluated seed predation in fragmented landscapes, in which lower species diversity is expected to modifying ecological interactions. The rates of seed removal by mammals were investigated in a continuous forest and two fragmented patches of Premontane Tropical Moist Forest, in Monteverde, Costa Rica. The composition of mammalian seed-predators in each site was recorded during 16 months. The removal of four native tree species of experimental seeds: Ocotea valeriana and Ocotea whitei (Lauraceae), Panopsis costaricensis (Proteaceae) and Billia colombiana (Hippocastanaceae) in forest understories was followed during two annual fruiting seasons for each species. Results indicated similar species composition of seed-predators between continuous forest, the largest fragment (350 ha). However the smaller fragment (20 ha), had fewer seed predators. In this fragment, the specialized seed predator Heteromys desmarestianus (Rodentia) was more abundant. Unexpectedly, seed-predation in the two forest fragments and the continuous forest did not differ statistically for any of the seed species. Apparently, the higher abundance of small seed-predators in the fragments was compensated by the absence of medium and large seed-predators, like Agouti paca, Dasyprocta punctata (both Rodentia) and Pecari tajacu (Artiodactyla) recorded in continuous forest. Removal of experimentally-placed seeds was higher when the number of naturally occurring seeds in the sites was lower. This result could best be attributed to differential satiation of seed predators rather than differences in richness or abundance of seed predators.

Seed predation by mammals in forest fragments in Monteverde, Costa Rica

Few studies have evaluated seed predation in fragmented landscapes, in which lower species diversity is expected to modifying ecological interactions. The rates of seed removal by mammals were investigated in a continuous forest and two fragmented patches of Premontane Tropical Moist Forest, in Monteverde, Costa Rica. The composition of mammalian seed-predators in each site was recorded during 16 months. The removal of four native tree species of experimental seeds: Ocotea valeriana and Ocotea whitei (Lauraceae), Panopsis costaricensis (Proteaceae) and Billia colombiana (Hippocastanaceae) in forest understories was followed during two annual fruiting seasons for each species. Results indicated similar species composition of seed-predators between continuous forest, the largest fragment (350 ha). However the smaller fragment (20 ha), had fewer seed predators. In this fragment, the specialized seed predator Heteromys desmarestianus (Rodentia) was more abundant. Unexpectedly, seed-predation in the two forest fragments and the continuous forest did not differ statistically for any of the seed species. Apparently, the higher abundance of small seed-predators in the fragments was compensated by the absence of medium and large seed-predators, like Agouti paca, Dasyprocta punctata (both Rodentia) and Pecari tajacu (Artiodactyla) recorded in continuous forest. Removal of experimentally-placed seeds was higher when the number of naturally occurring seeds in the sites was lower. This result could best be attributed to differential satiation of seed predators rather than differences in richness or abundance of seed predators. Rev. Biol. Trop. 57 (3): 865-877. Epub 2009 September 30.

Pocos estudios han evaluado la depredación de semillas en ambientes fragmentados, en éstos la menor diversidad de especies debe estar modificando las interacciones ecológicas. Se investigó la remoción de semillas por mamíferos en un bosque continuo y dos fragmentos en Monteverde, Costa Rica. Se registró la composición de mamíferos en cada sitio durante 16 meses y se observó la remoción de semillas experimentales del suelo del bosque. Se utilizó semillas de cuatro especies de árboles: Ocotea valeriana, Ocotea whitei, Panopsis costaricensis y Billia colombiana, durante dos periodos anuales de fructificación cada una. Los resultados indican una composición de depredadores de semillas similar entre el bosque continuo y el fragmento de 350 ha, más diversos que el fragmento de 20 ha, en el cual el especialista en semillas Heteromys desmarestianus fue más abundante. La depredación de semillas entre el bosque continuo y los fragmentos no fue estadísticamente diferente al considerar todas las especies de semillas, debido a la mayor abundancia de depredadores pequeños, que pudo compensar la ausencia de depredadores de talla mediana y grande que sí están presentes en el bosque continuo. La depredación sobre semillas fue mayor cuando la oferta de semillas no experimentales fue menor, indicando que la saciedad de los depredadores puede estar determinando la remoción de semillas en fragmentos, más que la riqueza o abundancia de especies depredadoras.