Contribution of flower visitors as effective pollinators along a disturbance gradient

Research on pollination systems has been focused greatly on how pollinator visits structure mutualistic networks, where pollinator effectiveness that defines the quality of those visits has received much less attention. Uncovering the factors responsible for interspecific variation in pollination effectiveness in ecologically distinct pollinator taxa is crucial to predict their role in ecological and evolutionary processes, particularly in view of major global changes in pollinators resulting from human modifications of natural habitats. Impoverished pollinator assemblages in disturbed forests may indicate the loss of pollination services, which negatively affects plant reproduction and can lead to the breakdown of mutualistic relationships. Our goal is to evaluate the relative contribution of distinct functional groups of flower visitors
to plant reproductive success and identify the mechanisms behind pollination effectiveness along a disturbance gradient in neotropical forests. Specifically, we aim to (1) analyze interaction patterns between plants and pollinators from two functional groups in forests with different levels of disturbance, (2) compare the contribution of two distantly related pollinator taxa (hummingbirds and bats) in the quality of pollination effectiveness, (3) assess how temporal pollinator niche segregation and ecological specialization of interacting species relate to plant reproduction and (4) investigate the ability of morphological traits of interacting partners to predict seed and fruit set. By addressing these aims, we will be able to (i) gather a unique dataset on plant-pollinator interactions including diurnal and nocturnal flower visitors, with a more comprehensive approach, thereby filling a persistent major gap in pollination studies; (ii) develop an experimental setting to quantify pollination effectiveness allowing for an estimate of the genuine role of pollinators in ecological communities; (iii) document to what extent pollinator visits to plants depict interactions that contribute to plant fitness and thus, provide a more refined insight into network theory; (iv) evaluate the underlying mechanisms that may influence variation in pollination effectiveness for a better understanding of how ecological and trait-based processes shape mutualistic networks. The proposed research will be conducted in the current context of anthropogenic land cover change to evaluate how habitat disturbance affect plant reproduction through shifts in pollination effectiveness. This knowledge is essential to assess how a loss of particular pollinator species or functional groups in response to habitat disturbance may affect plant fitness and consequently the structure and functioning of tropical ecosystems.

Objetivo

Evaluar la contribución relativa de distintos grupos funcionales de visitantes de flores al éxito reproductivo de las plantas e identificar los mecanismos detrás de la efectividad de la polinización a lo largo de un gradiente de perturbación en los bosques neotropicales.

• Financiamiento: CONARE (Costa Rica) - DFG (Alemania)
• Área de estudio: nueve localidades en los alrededores de Pérez Zeledón, zona sur, Costa Rica.