Variation across river channels in demographic dynamics of a riparian herb with threatened status: management and conservation implications

PREMISE OF THE STUDY: Gesneria pauciflora is a rare-threatened plant growing in riparian forests. Periodic disturbances, expected in this habitat, could influence demographic dynamics on plant populations, yet their impact may not be the same across watershed. We hypothesize that differences in disturbances between the main-channel and tributaries may lead to spatial dissimilarities in population growth rate (λ), structure, and fecundity.
METHODS: 1277 plants were tagged and monitored over a 1.5-years period. Every 6-months we measured plant size, survival and fecundity, in addition to appearance of seedlings. These variables were applied in Integral Projection Models to assess the population status of G. pauciflora.
KEY RESULTS: Plants in the main-channel were smaller but were more likely to flower and fruit than those in the tributaries. Overall mortality was greater in the main-channel and more so during the rainy season. At both sites λ ranged from 0.9114-0.9865, and survival/grow...