Fruit colors

Fruits show an immense diversity of colors and displays. However, we are still far from a general theory for the evolution of fruit displays. The main elements of those displays do not only include color itself, but also characteristics of the fruit “design” (ow the fruit is built) like number of seeds, amount of pulp, size, etc., and the nutrients in the pulp (both macro- and micro-nutrients, as well as secondary compounds). All this adds an extraordinary complexity and diversity to the fruit displays. Together with Alfredo Valido and Martin Schaefer I’ve been exploring the evolutionary patterns of fruit traits for the Iberian Peninsula fleshy-fruited flora (ca. 120 species). We studied whether correlated trends between these elements of the display (design, nutrients, color) have been maintained through the phylogenetic diversification of the flora. We found some interesting patterns of covariation between sugar content, lipid content, and color that suggest predictable patterns of fruit evolution in relation to the main types of frugivores feeding on the fruits. Our results suggest that the evolution of fruit displays has been quite constrained by history, yet selection by frugivores might have contributed to marked and predictable covariation among color and nutrient contents. This is an interesting finding to understand the evolution of visual signals in plants, acting to attract diverse suites of animal frugivores that can act as legitimate dispersers of the seeds. Our work is now in press in Journal of Evolutionary Biology.

PhD thesis defense by Débora Rother

  PhD thesis defense by Débora Rother: “ Débora defended her thesis at UNESP (Rio Claro, Brazil) the 30th Nov. The thesis is entitled: ‘Dispersão de sementes e processos de limitação demográfica de plantas em ambientes com e sem bambus na floresta pluvial Atlântica’. She addressed the patterns of regeneration in the Atlantic rainforest of SE Brazil by combining observational studies of seed rain and seedling emergence and experimental seed addition. She studied Euterpe edulis, Sloanea guianensis, and Virola bicuhyba. The dispersal patterns of these species and their regeneration are deeply influenced in this forest by the presence of bamboo (Guadua tagoara) stands. This heterogeneity causes variation in the composition of the frugivorous avifauna and the density of seeds and established seedlings. She addressed the specific demographic transitions from dispersed seed to established saplings that can limit the natural regeneration of these forests. Bamboo stands influenced seed rain patterns in the complex mosaics of Atlantic rainforest areas, with a variable importance across seasons on the abundance of recruits and species richness of the seed rain. Besides, the hotspots of recruitment were shown as extremely dynamic and related to the spread and decline of G. tagoara stands. Bamboos promote the forest heterogeneity, but the characteristics of rapid colonization of G. tagoara and its invasive behavior can be one additional factor for limiting the growth of plant community and thus its management is important.
The defense went very well and she has already in press or submitted manuscripts of several chapters. Congratulations Dé for an excellent work!”

(Via Weblog de Pedro.)

Long-distance dispersal events

The long and short of it

Back from the very interesting workshop organized in Madrid by Juanjo Robledo-Arnuncio. We focussed on long-distance dispersal events (LDD) and their importance to understand the potential responses to climate change. Changes in the environment will force adaptations or long-distance migration and range expansion in plants. Thus a key question is, are the LDD services provided by animal frugivores potentially allowing this environmental tracking.
We have been advancing a lot in understanding the local, stand-level patterns of dispersal and their consequences. Yet there are numerous conceptual and methodological challenges to understand migration among patches or fragments. LDD events > 500 km will be extremely difficult to assess in a robust way with current techniques, given the tremendous logistic challenge of sampling all the potential available pollen and seed sources. However, LDD events @100 km scale are probably affordable to estimate with a combination of mechanistic models (i.e., relying on high-precision satellite tracking of animal movement combined with physiological models) and genetic tools. Large scale sequencing and cheaper DNA analysis will help to genotype massive amounts of samples and allow the identification of rare immigrants, even when migration rates are low. Some lasting conceptual challenges include the estimation of 2D dispersal kernels that accommodate the complex reality of natural landscapes and the complexities of animal movement, which is quite often markedly directional and anisotropous.

The program of this interesting and thought-provoking workshop is here:

Mini-symposium

Long distance dispersal (LDD): perspectives and new directions

December 2nd, 2010

Sala Javier Palacios
Centro de Investigación Forestal (CIFOR)
Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA)
Ctra. de la Coruña km 7,5
Madrid

8h45 – 9h00. Introduction (Juanjo Robledo-Arnuncio)

9h00 – 10h00 Keynote Speaker: Prof. Ran Nathan (Univ. Jerusalem)
A movement ecology approach to study LDD of plants

10h00 – 10h50. Prof. Pedro Jordano (EBD-CSIC)
Frugivores, seeds and genes: tracking the LDD events and their consequences

10h50 – 11h20. Coffee break

11h20 – 12h10Dr. Frederic Bartumeus (CEAB-CSIC)
LDD: Seed curves, Skewness and Anomalous Diffusion

12h10 – 13h00. Prof. Miguel Ángel de Zavala (Univ. Alcalá)
Species distribution models and long-range dispersal

13h00 – 14h30. Lunch at INIA

14h30 – 15h20. Dr. Juanjo Robledo-Arnuncio (CIFOR-INIA)
Genetic estimation of LDD among plant populations

15h20 – 17h00. Open Discussion (+ coffee)

17h00. End of mini-symposium

Talk

Forthcoming talk – Dispersal near and far

An invited talk, “Frugivores, seeds and genes: tracking the LDD events and their consequences” in the workshop organized by Juanjo Robledo-Arnuncio: Long-distance dispersal: perspectives and new directions. CIFOR-INIA, Madrid.