Topology of Plant - Flower-Visitor Networks in a Tropical Mountain Forest: Insights on the Role of Altitudinal and Temporal Variation.

Understanding the factors determining the spatial and temporal variation of ecological networks is fundamental to the knowledge of their dynamics and functioning. In this study, we evaluate the effect of elevation and time on the structure of plant-flower-visitor networks in a Colombian mountain forest. We examine the level of generalization of plant and animal species and the identity of interactions in 44 bipartite matrices obtained from eight altitudinal levels, from 2200 to 2900 m during eight consecutive months.

Effect of biotic and abiotic factors on diversity patterns of anthophyllous insect communities in a tropical mountain forest.

The determinants of diversity are a central issue in ecology, particularly in Andean forests that are known to be a major diversity hotspot for several taxa. We examined the effect of abiotic (elevation and precipitation) and biotic (flowering plant diversity) factors considered to be decisive causal factors of diversity patterns on anthophyllous insect communities on mountain forest. Sampling was carried out in 100-m transects at eight elevational levels and during a period of 8 months.

Restricted pollen flow of Dieffenbachia seguine populations in fragmented and continuous tropical forest.

Habitat fragmentation can change the ecological context of populations, rupturing genetic connectivity among them, changing genetic structure, and increasing the loss of genetic diversity. We analyzed mating system and pollen structure in two population fragments and two continuous forest populations of Dieffenbachia seguine (Araceae), an insect-pollinated understory herb in the tropical rain forest of Los Tuxtlas, México, using nine allozyme loci. Mating system analysis indicated almost complete outcrossing but some inbreeding among the adults.