Dispersión a larga distancia por animales y conectividad entre poblaciones de plantas insulares: la extinción de los mutualismos y sus consecuencias
Long-distance dispersal by animals and connectivity between island populations of plants: the extinction of mutualisms and its consequences
Investigador principal
Pedro Jordano
Entidad financiera
MIN ECONOMÍA Y COMPETITIVIDAD
Fecha de inicio
Fecha de fin
Código
CGL2013-47429-P
Departamento
Ecología y Evolución
Investigadores
Valido, Alfredo
Descripción
Recientemente ha florecido el interés por el estudio de los patrones de flujo génico en paisajes heterogéneos, especialmente por la creciente demanda para comprender cómo procesos asociados a la acción humana afectan a poblaciones de animales y plantas e influyen en su viabilidad. En plantas en las que los animales influyen directamente en el flujo génico via polen y semillas, la variabilidad genética aparece fuertemente estructurada a diferentes escalas espaciales, muy dependiente de los procesos de dispersión. Una persistente limitación en estas aproximaciones ha sido el poder caracterizar la frecuencia y alcance de los eventos de dispersión a muy larga distancia (LDD), que son de importancia central en procesos de colonización y potencial de respuesta a cambio global. Nuestro grupo de investigación es pionero a escala mundial en el estudio de sistemas naturales de dispersión de plantas, combinando técnicas de campo (radio-seguimiento) con análisis genéticos de última generación y modelos mecanicistas para evidenciar este tipo de eventos y su importancia en poblaciones naturales. En el presente proyecto pretendemos analizar los patrones de conectividad entre fragmentos poblacionales de una planta endémica canaria, Neochamaelea pulverulenta, caracterizada por la alta especificidad de sus interacciones mutualistas con polinizadores y dispersores de semillas. Pretendemos desvelar los patrones de dispersión de polen y semillas a diferentes distancias, con una consideración explícita del espacio y analizar las consecuencias de la extinción reciente de algunos de estos mutualistas (lagartos endémicos gigantes). Los objetivos contemplados en este proyecto abordan estudios genecológicos de estima directa de flujo génico utilizando estimadores de paternidad para semillas muestreadas de las copas de los arbustos y otras dispersadas por animales. Por otra parte evaluaremos patrones de dispersión a larga distancia por animales usando técnicas de máxima verosimilitud para asignar semillas dispersadas en una población a su arbusto y población de origen, basándonos en análisis microsatélites de ADN y en observaciones directas de los patrones de movimiento de los animales que depredan (cernícalos y alcaudones) sobre los frugívoros dispersantes de semillas (lagartos) combinadas con técnicas de seguimiento remoto. Nuestra hipótesis central es que el flujo génico via polen y semillas es muy limitado por la baja frecuencia de eventos LDD en especies endémicas insulares con alto grado de especificidad de interacciones mutualistas, lo cual además genera poblaciones muy estructuradas donde pueden incrementarse los efectos de depresión por endogamia. Con estas estimas evaluaremos modelos recientes de dispersión local y a larga distancia y la robustez de las estimas que se derivan para la cola de la distribución, actualmente el aspecto más problemático en estudios de dispersión de semillas por animales. Por otro lado podremos simular los paleo-escenarios de dispersión de semillas previos a la extinción de los lagartos gigantes y comprobar la existencia de señales genéticas de la pérdida de estos dispersores y de los servicios ecológicos únicos que comportaban para la flora endémica canaria.
Recent interest has flourished in the study of gene flow patterns in heterogeneous landscapes, with increasing demand for understanding how processes associated with human action affect animal and plant populations and influence their viability. In plants where animals directly mediate gene flow via pollen and seeds, genetic variability appears highly structured at different spatial scales, heavily dependent on propagule dispersal processes. A persistent limitation of these approaches has been to characterize the frequency and extent of dispersal events at very long distances (LDD), which are of central importance in processes of colonization and potential response to global change. Our research group is pioneer in the study of plant dispersal in natural systems, combining field techniques (radio-tracking) with last-generation genetic analysis and mechanistic models to assess these events and their importance in natural populations. In this project we analyze the connectivity patterns of among population fragments of the endemic Canarian plant Neochamaelea pulverulenta, which is characterized by the high specificity of their mutual interactions with pollinators and seed dispersers. Our goal is to characterize the patterns of pollen and seed dispersal to different distances, with an explicit consideration of space, and analyze the consequences of the recent extinction of mutualistic partners (endemic giant lizards). Our objectives in this project include genecological studies of direct estimates of gene flow using paternity estimators of seed progenies sampled from the plants and identification of source plants for seeds dispersed by animals. Moreover, we aim to evaluate LDD patterns mediated by animals using maximum likelihood techniques to assign a population dispersed seeds to the source population, based on microsatellite DNA analysis and direct observations of the movement patterns of animals combined with remote monitoring techniques. Results from a previous project revealed a highly limited pollination system where ants are the main pollinators, and severely limited seed dispersal by Gallotia lizards. We aim to assess the role of infrequent secondary dispersal involving LDD events by predatory birds that feed on lizards and potentially disperse seeds at long distances. Our central hypothesis is that pollen- and seed-mediated gene flow is strictly limited by the low frequency of LDD events in narrow-endemic plant species with highly specific mutualistic services, which in turns generates highly structured adult populations where the effects of inbreeding depression can increase. With these estimates we evaluate recent models of local and long-distance dispersal and the robustness of the estimates derived for the tail of the distribution, currently the most problematic and methodologically challenging aspect in studies of seed dispersal by animals. On the other hand we aim to model and simulate the seed dispersal paleo-scenarios prior to the extinction of the giant lizards and test for genetic signals of the loss of these dispersers and their unique ecological services for the Canarian endemic flora.
Recent interest has flourished in the study of gene flow patterns in heterogeneous landscapes, with increasing demand for understanding how processes associated with human action affect animal and plant populations and influence their viability. In plants where animals directly mediate gene flow via pollen and seeds, genetic variability appears highly structured at different spatial scales, heavily dependent on propagule dispersal processes. A persistent limitation of these approaches has been to characterize the frequency and extent of dispersal events at very long distances (LDD), which are of central importance in processes of colonization and potential response to global change. Our research group is pioneer in the study of plant dispersal in natural systems, combining field techniques (radio-tracking) with last-generation genetic analysis and mechanistic models to assess these events and their importance in natural populations. In this project we analyze the connectivity patterns of among population fragments of the endemic Canarian plant Neochamaelea pulverulenta, which is characterized by the high specificity of their mutual interactions with pollinators and seed dispersers. Our goal is to characterize the patterns of pollen and seed dispersal to different distances, with an explicit consideration of space, and analyze the consequences of the recent extinction of mutualistic partners (endemic giant lizards). Our objectives in this project include genecological studies of direct estimates of gene flow using paternity estimators of seed progenies sampled from the plants and identification of source plants for seeds dispersed by animals. Moreover, we aim to evaluate LDD patterns mediated by animals using maximum likelihood techniques to assign a population dispersed seeds to the source population, based on microsatellite DNA analysis and direct observations of the movement patterns of animals combined with remote monitoring techniques. Results from a previous project revealed a highly limited pollination system where ants are the main pollinators, and severely limited seed dispersal by Gallotia lizards. We aim to assess the role of infrequent secondary dispersal involving LDD events by predatory birds that feed on lizards and potentially disperse seeds at long distances. Our central hypothesis is that pollen- and seed-mediated gene flow is strictly limited by the low frequency of LDD events in narrow-endemic plant species with highly specific mutualistic services, which in turns generates highly structured adult populations where the effects of inbreeding depression can increase. With these estimates we evaluate recent models of local and long-distance dispersal and the robustness of the estimates derived for the tail of the distribution, currently the most problematic and methodologically challenging aspect in studies of seed dispersal by animals. On the other hand we aim to model and simulate the seed dispersal paleo-scenarios prior to the extinction of the giant lizards and test for genetic signals of the loss of these dispersers and their unique ecological services for the Canarian endemic flora.