AgriPop Friday Talks

Friday's Agripop Talk - 29 March 2013

Hey, we've got a busy day ahead -- 2 talks on the same day!

29 March 2013 - 11:00 - Salle Seminaire

Learning trophic networks : apprehending patterns and generalities from real data

David Bohan

Who eats whome and how to find this out without the need to actually observe the act of predation, or without the need of lengthy analysis of the diet -- just come and listen how David uses commonly available distribution and abundance data to infer trophic relationships between carabid beetles and weeds in arable farmlands.

David worked until recently in the UK at Rothamsted, after which he moved to Dijon to take up a IINRA DR1 position.

 

Lindy Mary Corredores Hurtado

29 March 2013 - 15:30 - Salle Ragondin
Bees and their landscape: mapping the distribution of floral resources in agricultural landscapes and their use by wild bees 

Lindy will present us her sampling plan for mapping the distribution of wild flower resources, especially of poppy flowers, and assess their use by domestic bees. Please come all and help out Lindy - she'll be keen to hear your feedback and advise!

And, what better way to finish the week listening to a talk about bees and wild flowers ... just before pub time??? :-) So, see you all there et bon weekend!

AgriPop Friday Talks

Friday's Agripop Talk

21 March 2013 - 11:15 - Salle Ragondin

The structuring processes of passerine’s communities, the share of the stochastic, environment and biotic interactions

Laura Henckel

Actually, it's a thursday talk!

Which mechanisms drive the assembly of communities is a longstanding question in ecololgy. However there is a renewed of interest for this problematic since the last decades due to some original studies : coexistence theory of Chesson (2000), Hubbell’s unified neutral theory (2001), or due to new available tools (ie. phylogenetic). But notwhithstanding the numerous studies, the debate remain open and there is no consensus amoung the various theories. The controversies concern in particular the relative importance of the processes involved (stochasticity, dispersal, biotic interactions or environmental screen).

Because it is difficult to test directly the effect of these processes via a mechanistic model, a wide range of indirect approachs were proposed in recent years. This great diversity of methods can partly explained the divergence of conclusions. Furthermore, it appears that these results are strongly dependent on the scale of analysis (spatial extent and grain), on taxa and even on the characteristic of the study site. Another thing is that a wide part of the studies on community assemblages remain theoretical and most of the others concern micro-organisms or plant communities. For these reasons further studies are needed, combining both a consistent set of methods and a multi-scale approach in a way to strengthen the results and reduce biases or misinterpretation. We therefore use some of these methods in way to understand the assembly processes that structure the passerine community in the particular context of the intensive agro-ecosystems.

This question constitutes both a scientific and societal challenge in the context of the strong decline of farmland birds observed during the past decades due to agricultural intensification.  For this purpose I will use the point count data collected between 2009 to 2012 on the workshop area “Plaine et Val de Sevre”, which are distributed on the whole area (every 1km²) allowing me to conducted a multi-scale approach by varying the grain and the extent of analysis.  A set of different methods will be used to distangle the processes involved (ie. multiple regressions on distance matrix, co-occurrence analysis) and different models will be compared (stochastic vs different determist models) to try to identify which processes are involved and at which scale. This work constitutes a preliminary study for my PhD which will focus more specifically on the environmental factors and in particular on the landscape heterogeneity effect (crop composition and configuration) on farmland birds.

AgriPop Friday Talks

Friday's Agripop Talks

  15 March 2013 - 11:30 - Salle Ragondin

The evolutionary history of Petrels: 

A microevolutionary and macroevolutionary approach 

 

Adriana Iglesias Vasquez

 Tube-nosed seabirds. Yes, exactly. This week's seminar will be about "tube-nosed seabirds in the bird order Procellariiformes" (Wikipedia docet), commonly known as petrels. But you can do much better and these birds have stimulated the immagination of poets -- you might recall:

Up above the sea's grey flatland, wind is gathering the clouds. In between the sea and clouds proudly soaring the Petrel, reminiscent of black lightning.

Glancing a wave with his wingtip, like an arrow dashing cloudward, he cries out and the clouds hear his joy in the bird's cry of courage.

In this cry -- thirst for the tempest! Wrathful power, flame of passion, certainty of being victorious the clouds hear in that bird's cry.

 Much better, isn't it? And, it turns out, petrels are also interesting from an evolutionary point of view, with a clear lack of research about their evolutionary history. And that's the subject of Adriana's PhD thesis:

Evolution in simple words is understood as the change in the form and behavior of organisms among generations. Variation in the organism’s forms occurs at all levels from DNA sequences to macroscopic morphology promoting the diversity of life (Futuyma, 1998). To understand the processes that shape such diversity evolution could be studied from two approaches acting at two levels and on two timescales: microevolution and macroevolution. Microevolution acts rapidly within populations through adaptive and neutral evolution while macroevolution occurs slowly and the patterns it produces are driven by speciation and extinction (Stearns & Hoekstra, 2005).

My thesis research will focus on these two evolutionary scales having as a biological model a group of the Procellariidae family well known as Petrels. The evolutionary history of these seabirds is unclear, as most of evolutionary studies have focused on terrestrial birds, and likely complex,  with two opposed evolutionary forces shaping its genetic structure: phylopatry and mobility. This Friday I will introduce you the three main questions from which I will develop my thesis: 

1. Is there a correlation between neutral genetic variation and morphological traits? 

2. Is the pattern of genetic differentiation concordant across molecular marker types - nuclear and mitochondrial? 

3. What is the mechanism of speciation that better explains the formation of new species of Petrels?

Thus, come this Friday - usual time and place: 11:30 Salle Ragondin.

And the Petrel soars while crying, reminiscent of black lightning, like an arrow piercing the clouds, 

with his wing rips foam from the waves.

...

AgriPop Friday Talks

Friday's Agripop Talks

  08 March 2013 - 11:30 - Salle Ragondin

Spatial depletion models highlight distribution rules of foraging sea ducks

Vincent Tolon

Seaducks? Yes, there are also ducks in the sea, not only in your local lake! And what do they eat? Clams and other shellfish - but no, not exactly as you are just thinking:

Immage downloaded from http://bit.ly/YCSM3G

... but indeed the same ones that we humans enjoy eating. And one problem with similar resources is that, once a forager takes them, they get depleted! So, how to forage for similar resources? Vincent will address this question using a population of seaducks living on the northern coast of France as study system. Here's a summary from Vincent of what he will show us this week:

Understanding distribution rules of foragers in their environment is one of the main topics of behavioural ecology. For predators that prey on non-renewable resources, depletion (i.e. the simple removal of food that other individuals can consume) is a likely mechanism driving population distributions. Since two decades, spatial depletion models (SDMs) have been developed to predict effects of resource depletion on predator distributions. These models commonly predict that predators should first exploit the richest patch, and include other patches when they become as profitable as previously depleted areas. 

SDMs can help determining how the distribution should change in response to resource depletion, and can provide a reference over which more complex distribution rules (e.g. density dependence) can be tested. We located groups of common scoters Melanitta nigra foraging on benthic communities on a French coast used as wintering areas. We first tested if simple “Ideal Free” SDMs can explain theirs seasonal distribution dynamics between and within large ranges (areas of several dozen of km²). We tested such models for different combination of prey type and determined how much the model/data matching can be explained by density variations.

And here also a cool GIF of Vincent's model predictions:

Cool, isn't it? So, come and listen!

AgriPop Friday talks

Friday's Agripop Talks

01 March 2013 - 11:30 - Salle Ragondin

Land use influences the ground beetle Poecilus cupreus at different spatial and temporal scales in an agricultural landscape

Ronan Marrec

Certains facteurs peuvent contraindre la distribution et les abondances des espèces. L'abondance d'une population à n'importe quel endroit d'un paysage a été résumée comme fonction des taux de natalité et de mortalité; la capacité intrinsèque de l'espèce à se disperser et se déplacer au sein et entre les sites; et l'accessibilité des sites aux individus dispersant.

Dans les environnements complexes et instables, tels que les agroécosystèmes, l'accessibilité et la favorabilité des habitats pourraient être restreintes, pour deux raisons majeures. Premièrement, la plupart des cultures sont annuelles, et deuxièmement, la plupart des cultures ont des phénologies asynchrones et variant dans le temps. En conséquence, les terres arables ne fournissent pas un habitat constant au cours de l'année et d'une année sur l'autre.
Dans de tels environnements changeants, j'étudie (i) quels types d'éléments paysagers affectent les patrons de distribution et d'abondance chez un Coléoptère carabique très abondant dans les agrosystèmes de l'ouest de la France, Poecilus cupreus (L.), et (ii) à quelle(s) échelle(s) ils influences ces patrons. Je vous présenterai vendredi 1er mars mes résultats sur ce sujet...

Some factors constrain species' distribution and abundances. The population abundance at any location in a landscape has been summarized as a function of local birth and death rates; the intrinsic ability of species to disperse and move within and between areas; and the accessibility of sites to dispersing individuals.

In complex and unstable environments, such as agroecosystems, accessibility and suitability of habitats could be restricted in time and space, for two main reasons. First, much of the fields are annual, and secondly, much crop identities have asynchronous and varying phenologies. As a consequence, arable fields do not provide a constant habitat throughout the year and from one year to another.
In such moving environments, I am studying (i) which kinds of environmental features affect distribution and abundance patterns in a very abundant carabid beetle in our agrosystems in Western France, Poecilus cupreus (L.), and (ii) at which scale(s) they influence these patterns. I will present you on Friday 1st March my results on this subject...

AgriPop Friday talks

Friday's Agripop Talks

  22 February 2013 - 11:30 - Salle Ragondin

Master student project presentations

Do you remember? Just the other day we were discussing that we had never had so many people working on community ecology in our team as this year. Well, here's an example - two M2 project presentations, both on community ecology! Cool, isn't it? And both are really nice and interesting projects, so come along and help the students discuss their project plans!

Relations plantes-criquets en milieu agricole: étude de l'abondance des criquets par une approche "traits fonctionnels"

Gaetane Le Provost

Aspects temporels de la structuration des communautés adventices
Klervi Tocze

So, to start with, where do these figures come from? Yep, that painting included ... come on, it's from some of those so-called 'classics or foundation papers'. There might be some candy for those guessing it (Disclaimer: this promise has the same validity as politicians' promises before elections).

Going back to the upcoming M2 projects - Gaetanne aims to understand what structures grasshopper communities in agricultural landscapes:

Les communautés d’herbivores constituent un maillon essentiel au sein des réseaux trophiques. L’organisation de ces communautés dépend de processus « bottom-up » et « top-down ». Afin de comprendre la structure de ces communautés, il parait donc nécessaire de prendre en compte le réseau trophique dans son ensemble : ressources, prédateurs, mais également les facteurs abiotiques qui vont influencer la qualité de l’habitat. 

Dans un premier temps, les patrons d’abondance de plusieurs espèces de criquet seront analysés en fonction de la qualité et quantité de ressource, de la densité de prédateurs, du microclimat. Or la sensibilité des différentes espèces de criquets à ces facteurs dépend de la variabilité de leurs traits fonctionnels.  

Dans un deuxième temps, une approche fonctionnelle sera donc utilisée pour décrire la niche écologique des différentes espèces et comprendre leurs réponses aux facteurs du milieu, à travers l’étude de leurs traits fonctionnels.

Photo by eliz, downloaded from http://www.fotonatura.ro: http://bit.ly/15wbNsL

 Klervi instead is interested in wild plants which have the unfortunate habit to try to grow on crop fields - often called 'weeds' - and the processes driving temporal variation in community structure:

Comprendre les règles d’assemblage des communautés d’adventices apparait comme essentiel pour gérer à la fois leurs impacts négatifs sur la production agricole et  positifs sur le maintien de la biodiversité (en tant que ressources et habitats). Il existe en écologie des communautés, plusieurs théories sur les patterns observés. En effet, la structure des communautés peut être déterminée par différents facteurs environnementaux, spatiaux ou encore temporels.

On sait que les adventices présentes dans une parcelle sont dépendantes à la fois des pratiques culturales mises en place mais également de la banque de graines présente. Cette dernière étant influencée par les communautés précédentes, sous l’influence des assolements passés. C’est pourquoi, lors de ce stage, je vais étudier l’impact des facteurs temporels à travers l’effet des rotations culturales sur les communautés d’adventices.

 

photo by Jean-François Sérot, downloaded from http://serotjf.com

See you on Friday!

  

 

AgriPop Friday talks

Friday's Agripop Talks

  15 February 2013 - 11:30 - Salle Ragondin

Assessing the effectiveness of different  approaches to species conservation

AndreaSantangeli

Finnish Museum of Natural History, University of Helsinki, Finland

from: Milky Way Scientists facebook page

OK, don't worry, that's not Andrea, it's some other unlucky bloke. And the talk will also not be directly about eagles.

Actually, Andrea's talk will not be taxon specific, as it addresses an important question of general concern, i.e. how to assess the effectiveness of alternative approaches to conserve species. Especially given the high prevalence of highly altered, human-dominated landscapes, it is not trivial to understand how to conserve the biodiversity that persists in these areas.

Now, to make sure that I stop writing silly things, let's use Andrea's own words -- though I may continue inserting random pics :-)

Humans have used natural resources for thousands of years, and created and maintained extensive traditional landscapes that nowadays support important biodiversity in forested and open-land biomes. However, these landscapes have undergone massive changes during recent decades owing to the intensification of extraction regimes in forests and farmlands across large regions of the globe. As a consequence, most species that have adapted and thrived for centuries or millennia in traditionally managed landscapes are showing signs of population decline and regional extinctions. 

To revert the negative impacts of modern intensive practices, large sums of money and various conservation approaches have been implemented. Unfortunately, such large efforts have not always been based on solid and updated scientific evidence, and therefore they have achieved only mixed successes. In order to maximise the impact of limited conservation resources, it is crucial that evaluation studies are carried out. These would ultimately allow learning from past actions and take better decisions in the future. 

 from: http://bit.ly/Z9NPmk

Here I evaluate the effectiveness of species-specific conservation measures implemented in contrasting landscapes (from forest to farmland) and with different underlying approaches, from a voluntary inexpensive approach (only based on self-motivation of landowners), a voluntary market-based approach (where landowners are compensated), to a compulsory approach (where landowners have no choice; achieved through land reservation or legislation).

After evaluation of their benefit to wildlife, I show that some expensive and coercive management interventions may result unnecessary; some, like legislation, may not be effective at achieving their goal while others, such as inexpensive voluntary approaches, can achieve important results with very limited resources. 

Overall, the case studies presented here lead to a general conclusion that evaluating conservation interventions can reveal relevant and sometimes unexpected outcomes that have important implications for improving the cost-effectiveness of conservation efforts.

Interesting, isn't it? So, see you all Friday am!