Seed dispersal by megafauna (extinct and extant)

I’ll be posting a series on megafauna (extinct and extant) and megafauna-dependent plants that I’ve been contributing to our Facebook page Frugivores & Seed Dispersal during the month of December. The posts focused on megafauna frugivores and megafauna-dependent fruits and seeds, and the processes of dispersal associated with them. I also included other interesting posts on frugivory and seed dispersal, as ever, but megafauna was the focus. Hopefully we contribute to a better appreciation of the distinct ecological roles and the contribution of megafauna species to the functioning and maintenance of ecosystems around the world, specifically on their role as frugivores and seed dispersers.

fig-9-cada-um

Among the most spectacular frugivores and seed dispersers we find the Megafauna species, those amazing beasts that impress every naturalist because of their adaptations, life histories, and specific traits. Yet megafauna species are being particularly hard hit by human-driven activities, notably hunting and deforestation. Megafauna species are traditionally defined as being above 40 kg body mass (i.e., > 100 lb), and include a full range of mammals (e.g., rhino, elephants, a number of antelopes, large primates), birds (e.g., ostrich, cassowary, emu), and reptiles (e.g., varanids, turtles). Moreover, think about the late Pleistocene (~12 Kyr BP) extinction of an even richest diversity of megafauna species: toxodons, terrestrial sloths, mamuths, gliptodons, gomphoteres, etc. The study of frugivory and seed dispersal (FSD) by megafauna opens a number of extremely interesting questions, ranging from the role of past history in shaping fruit traits, the lasting signatures of past extinctions of major seed dispersers for plants (e.g., in the genetic pools), the conflicts and interactions with humans in natural and seminatural habitats, the role of extremely long-distance seed dispersal by megafauna and its collapse following extinction, etc.

Illustration: Dadi, “Cada um”.

 

Rey Jaime I Award, Environmental Sciences


 

I’m very honored with being awarded the Rey Jaime I Award in Environmental Sciences this year. I was surprised with the decision of the jury during my stay in Brazil during this year’s Ciência Sem Fronteiras stay. It was great to have many, many messages with support and congratulations from many colleagues. My sincere thanks to all them!

I’m very happy with the award, as it aids supporting conservation efforts in the natural areas where I do my field work: Cazorla, Doñana, Alcornocales, Islas Canarias.

How do furgivorous birds build-up their fruit meals?

This is the third part of a trilogy of papers dedicated to understanding the evolution of fruit colors and visual signals evolved by plants to attract animal mutualists. The paper is now available online at the Proceedings of the Royal Society, Biology website.

Theory predicts that trade among mutualists requires high reliability. Here, we show that moderate reliability already allows mutualists to optimize their rewards. The colours of Mediterranean fleshy-fruits indicate lipid rewards (but not other nutrients) to avian seed dispersers on regional and local scales. On the regional scale, fruits with high lipid content were significantly darker and less chromatic than congeners with lower lipid content.

Sylvia atricapillaSylvia borin

On the local scale, two warbler species (Sylvia atricapilla and Sylvia borin, above) selected fruit colours that were less chromatic, and thereby maximized their intake of lipids—a critical resource during migration and wintering.

PRSB 1

Figure. The trade of resources characterizing mutualistic interactions leads to multiple, repeated interactions among individual producers and consumers. For example, birds use visual information to decide which fruits to consume. Two individual birds combine different fruit species in their meals during a short feeding bout (t0 − t1), along their foraging sequence, in which they visited different fruiting plants. M1–M4 indicate the composition of four meals, i.e. the number of fruits consumed and their species identity, different fruits with different colours. We analyzed the combination of colors in field-sampled fruit meals in relation to the nutrient composition and food “reward” obtained by the birds. Birds used markedly non-random combinations of colors in their meals, indicating a significant choice of fruit meals maximizing energy intake.

In a passage and wintering area in SW Spain where I intensively studied these birds, the two warbler species consistently selected fruit color combinations that were significantly less chromatic, evidencing the use of color as a cue of nutrient rewards during short feeding bouts. Being extremely dependent on fleshy fruits during migration and wintering, these warblers use a very diverse set of fruit species to build-up reserves required for long-distance flights (garden warbler) or winter survival (blackcap).

It is amazing how selective were these birds in their choice of fruits. Even in a short feeding bout blackcaps can ingest up to seven different fruit species. I used analyses of fecal pellets, identifying not only seeds, but also fruit skins in the remains using a microscope, which enabled me to identify the number of different fruit species consumed during a short feeding bout. The fruit meals thus combine a varied assortment of flavors, pulp types, etc. The warblers have a very short gut passage time (16 moon on average- and up to 40 min), so that a sample of faecal material indicates the previous choices of fruits made by the bird, immediately before capture. I used mist-netted birds that were released after capture.

Warblers need to maintain a high throughput of fruits when relying on fruit food because fleshy fruits are a quite “diluted” type of food: not only they are rich in water, quite succulent, but they also have indigestible seeds that occupy very valuable space within the bird’s gut. The birds need to process all this stuff very rapidly in order to get enough “reward”. In turn this is good for the plant because the seeds are readily dispersed away from the mother plant. This is a mutualistic interaction driven by the visual cues used by the birds.

Our results indicate that mutualisms require only that any association between the quality and sensory aspects of signallers is learned through multiple, repeated interactions. Because these conditions are often fulfilled, also in social communication systems, we contend that selection on reliability is less intense than hitherto assumed. This may contribute to explaining the extraordinary diversity of signals, including that of plant reproductive displays.

Updated dataset on fruit colors in Dryad

  I’ve updated our dataset on fruit colors that we used in the Journal of Evolutionary Biology paper. The full metadata is here, in the Dryad open-source repository. You can find this and other datasets also in the web page.

Starting fieldwork in Teno Bajo

  Starting fieldwork in Teno Bajo: “ We (Alfredo, Néstor and myself) are this week with field work in Teno Bajo (Teneriffe), finishing georreferencing and sampling of orijama (Neochamaelea pulverulenta) plants in the study plots. The work is going fine in this spectacular site. We study seed dispersal by the Gallotia endemic lizards to analyze the consequences of this specialized dispersal system on the genetic structure of the plant.” (Via Weblog de Pedro.)

New papers

Forthcoming papers

New papers, to be published later this year, now in press include:
– Rodríguez-Sánchez, F., Hampe, A., Jordano, P. and Arroyo, J. 2010. Past tree range dynamics in the Iberian Peninsula inferred through phylogeography and palaeodistribution modelling: A review. Review of Palaeobotany and Palynology 00: 000-000. May 2010. doi:10.1016/j.revpalbo.2010.03.008

– Verdú, M., Jordano, P. and Valiente-Banuet, A. 2010. Temporal rearrangements in the phylogenetic structure of plant facilitation networks. Journal of Ecology 00: 000-000. August 2010. [DOI: 10.1111/j.1365-2745.2010.01731.x]

– Olesen, J.M., Bascompte, J., Dupont, Y.L., Elberling, H. and Jordano, P. 2010. Missing and forbidden links in mutualistic networks. Proceedings of the Royal Society of London Series B-Biological Sciences, 00: 000-000. [doi: 10.1098/rspb.2010.1371]

Last papers

Last papers: “Our last papers have appeared in Molecular Ecology Resources, dealing with the description of new DNA microsatellite markers for Frangula alnus and Rhamnus alaternus (Rhamnaceae), two species we study in Los Alcornocales area. The next related paper will describe the markers for Neochamaelea pulverulenta (Cneoraceae). These works are largely the result of efforts by our technicians JuanMi Arroyo and Cristina Rigueiro.”

(Via Weblog de Pedro.)

Moving to new building

Moving to a new building

It has been a long time since my last post here… We are now in a new house: at Isla de La Cartuja. Much better in terms of functionality and space but without the lovely charm of Pabellon del Perú. We moved to the Pabellon in April 1984, so it’s been a long time there.

Kimberly

Kimberly arrived

Kimberly Holbrook arrived today. She will be here with a post-doc contract (Juan de la Cierva post-doc from the Spanish Minsterio de Educación), working on seed dispersal patterns of tropical species compared to temperate species. What we want to do is to assess comparatively the long-distance dispersal patterns mediated by tropical and non-tropical frugivores.

Updates

Web page updates

I’ve updated the web page with new information about the research lines at the lab, projects, and personnel. This includes brief descriptions of the main research lines, collaborations, etc. All are accesible from the Research web page under Research Lines.

PhD thesis defense by Jofre Carnicer

Jofre Carnicer defended his thesis at Universitat Auntónoma de Barcelona. The thesis is entitled: “Species richness, interaction networks, and diversification in bird communities: a synthetic ecological and evolutionary perspective”. He addresses large-scale patterns of species diversity and interactions for passerine bird species, taking case studies with the North American avifauna, the bird fauna of Catalonia, and frugivorous birds in SW Spain. The defense went very well and he has already published or has in press manuscripts of several chapters. Congratulations Jofre for an excellent work!

Some updates after summer

After summer

Well, it has been a long time without news in the blog, but here we are again. 😉 Summer has been quiet; I’ve been at Cadiz coast with Myriam and Perico, with a short visit by Diego. It has been a great time to read, think and write but, again, no painting at all… 😦
After summer the group has been plenty of news. Geno Schupp and Janis Boettinger arrived in Sevilla for a new sabbatical year. We have plenty of time ahead to start new projects and revisit old ideas, besides enjoying the ‘tapas’ landscape around us.
We (Jordi, Jens and myself) got the Mercer Award of the Ecological Society of America for the Science paper; and Jordi, Jessica and Miguel Angel went to the meeting in San Jose (California) and enjoyed a splendid ceremony. This award is in recognition for the paper in Science (2006) on interaction asymmetries in mutualistic networks.
We have a new incorporation of Rocío Rodríguez, to start her PhD project on long-distance seed dispersal in Laurus nobilis and Frangula alnus. In addition, Itziar Sarasa also arrived to the group for a short-term stay until December with an introductory grant from CSIC.
Additional good news include the new grant-contracts that Arndt Hampe and Kimberly Holbrook obtained for the next 2 years in the group. Arndt is getting back to work on relict oak populations and Kimberly will keep going with the genetic analysis she started with Virola for her PhD, within a comparative project with Prunus.
Now I’m concentrating on the revision of the megafauna paper with Paulo and Mauro as well as in mss with Alfredo and Martin (fruit colors) and Jordi and Jens (networks); besides there is pending work with Geno on dispersal effectiveness and dispersal limitation that we want to finish. We really have a lot of things going on here, all great fun.

New paper on seed dispersal by animal frugivores in PNAS

New paper in PNAS just published

We have just published our paper “Jordano, P., C. García, J.A. Godoy, and J.L. García-Castaño. 2007. Differential contribution of frugivores to complex seed dispersal patterns. Proceedings National Academy of Sciences USA, 104: 3278-3282”. These are great news since it represents a great advance in the analysis of frugivore-created seed shadows. We document the differential contribution of different frugivore groups to seeds dispersed a given distance, using direct assignement procedires based on DNA genotyping methods. At the moment it’s the first approximation we have available to the total dispersal kernel of a plant species.
The paper has been extensively commented in the ‘Perspectives in Science’ section of Science journal. Please see the publications list for details.

Pre-doctoral grant available

Pre-doctoral grant available

La convocatoria de ayudas para becas predoctorales FPI está próxima a ser publicada por el MEC.

Dentro de nuestro proyecto “DISPERSIÓN DE SEMILLAS POR ANIMALES FRUGÍVOROS: EVENTOS A LARGA DISTANCIA Y REDES DE CONECTIVIDAD EN POBLACIONES FRAGMENTADAS” (CGL2006-00373), estamos interesados en recibir candidaturas para una beca FPI del MEC para desarrollar una Tesis doctoral.

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. El mantenimiento de esta estructura espacial se basa en la conectividad entre poblaciones via polen y semillas, distribuidas por animales mutualistas. En escenarios de fragmentados es esencial comprender cómo se estructura esta conectividad a fin de poder predecir los efectos de pérdida (extinción local) de poblaciones y limitación de los procesos de dispersión. En este proyecto abordamos estos aspectos centrándonos en especies forestales amenazadas o relictas, para las cuales ya disponemos de información a raíz de proyectos anteriores. En esta propuesta abordamos el problema de la persistencia de las poblaciones de estas especies basándonos en una mejor comprensión de la conectividad que existe entre ellas y de la dependencia de animales polinizadores y frugívoros para el reclutamiento. Nos centraremos en Olea europaea var. sylvestris, y abordaremos también aspectos demográficos y genéticos en Frangula alnus, Laurus nobilis, y Prunus mahaleb. Nuestra propuesta sintetiza las principales líneas de trabajo que mantiene nuestro grupo y aborda cuestiones clave sobre la preservación de la biodiversidad de especies, interacciones y acervo genético en escenarios de cambio ambiental. El enfoque es interdisciplinar, aunando diferentes aproximaciones (análisis estadístico de bases de datos, teoría de redes complejas, métodos de genética molecular y simulaciones de ordenador).

El trabajo de tesis se centraría en los aspectos de conectividad en poblaciones fragmentadas. Perfil requerido: formación en biología y/o ciencias ambientales con un buen expediente académico. Se valorarán positivamente los conocimientos en ecología, genética molecular y estadística, con una fuerte motivación e interés por estos temas. Se requiere inglés hablado/escrito con nivel alto. El trabajo previsto incluye tareas de campo y de laboratorio.

Las bases de la convocatoria serán publicadas próximamente por el MEC (ver http://www.mec.es/ciencia/jsp/plantilla.jsp?area=becasfpi&id=11 para convocatorias anteriores).

Las personas interesadas deben ponerse en contacto lo antes posible con Pedro Jordano adjuntando su CV actualizado (con datos de contacto) junto con copia de su expediente académico. El plazo de la convocatoria, que se publicará en BOE en breve, será sólo de unos 15 días. Más información sobre el grupo de investigación y sobre nuestro trabajo se puede encontrar en las páginas web:
http://ebd10.ebd.csic.es>
http://ieg.ebd.csic.es>

Cris García PhD defense

Cris García PhD defense

The defense of Cris’ PhD Thesis took place the 5th Dec at University of Sevilla. We had a great time and everything went well. Members of the committee were Salvador Talavera, Sophie Gerber, Miguel Verdú, José María Gómez, and Gabriel Gutiérrez. The thesis is entitled: “Patterns of animal assisted dispersal and gene flow via pollen and seeds in heterogeneous landscapes”.