Phenotypic plasticity to light of two congeneric trees from contrasting habitats: Brazilian Atlantic Forest versus cerrado (savanna).

The Brazilian Atlantic Forest is a typically multi-layer tropical forest, while cerrado (savanna) is a patchy habitat with different physiognomy. Despite these differences, both habitats have high light heterogeneity. Functional traits of Dalbergia nigra and D. miscolobium from the Atlantic Forest and cerrado, respectively, were evaluated under shade (25% of full sunlight) and full sunlight in a nursery experiment. We hypothesised that both species should benefit from high phenotypic plasticity in relation to light. Plasticity was estimated using the relative distance phenotypic index (RDPI). D. miscolobium had lower shoot growth under both light conditions, suggesting it has low competitive capacity in the forest environment, which could explain its limited ability to expand over areas of Atlantic Forest. The studied species exhibited photoprotection strategies under high light and improved light capture under low light. Stomatal conductance, ETR(max) (maximum electron transport rate), PPFD(sat) (saturating photosynthetically active photon flux density), chlorophyll and carotenoid content had higher RDPI than stem morphological traits. Although both species showed considerable phenotypic plasticity, D. miscolobium had higher RDPI for eight of 11 evaluated traits. This high plasticity could be one of the factors that explain the occurrence of this species in a wide range of environmental conditions, from open grassland to dense woodlands, and it could also reflect its adaptation to high light. D. nigra also had considerable plasticity and good growth performance in both shade and full sunlight, but its absence in areas of cerrado suggests that factors other than light limit its occurrence in these habitats.

Biología de roedores reservorios de hantavirus en Chile / Biology of hantavirus reservoir rodents in Chile

Es revisada la biología básica de los roedores potencialmente reservorios de hantavirus en Chile. La taxonomía y sistemática de cinco especies de roedores Muridae endémicos, el orizomino Oligoryzomys longicaudatus (reservorio primario), los akodontinos, Abrothrix longipilis y Abrothrix olivaceus, y los filotinos Loxodontomys micropus y Phyllotis darwini, son puestas al día con recientes modificaciones, así como sus caracteres externos, distribución geográfica, hábitat, etología, alimentación, ecología y reproducción. Especial atención se da a las relaciones filogenéticas entre especies de roedores sus grupos, así como con aquellas correspondientes a sus hantavirus huéspedes. Una asociación entre la evolución de ambos grupos parece emerger, sugiriendo co-evolución entre las especies de roedores virus. Esta importante hipótesis debería ser puesta a prueba. Son discutidas otras relaciones entre especies de roedores y sus huéspedes virales