Nati will spend three months in a research center in the USA

nati_2014Natalia Schroeder will spend three months at the Forestry and Range Sciences Laboratory, Pacific Northwest Research Station of the Forest Service in La Grande, Oregon, USA. She will be collaborating with Michael Wisdom, Mary Rowland and Ryan Nielson in her ongoing research on spacial dynamics and management of large native and domestic ungulates, and will start new studies comparing ungulate species in North and South America. Her stay in Oregon will be generously supported by CONICET, a post-doctoral fellowship from the US Forest Service, and the Williams Foundation. Safe travels, Nati!

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Second annual group retreat in Ñacuñán

An outdoor discussion during the first day of the retreat.

An outdoor discussion during the first day of the retreat.

We are back from our second annual group retreat, held at the Biological Station of Ñacuñán Biosphere Reserve. Following the success of our first retreat last year, we decided to establish the group retreat as a yearly activity. The idea is to have a couple of days of close academic interaction in a quiet, remote setting surrounded by nature—the kind of place we ecologists love. And of course, to have fun together.

We were thirteen participants, including eleven members of our group in Mendoza and two visitors from Córdoba (Julia Tavella and Luciano Cagnolo). During the retreat, each of us gave a 15 min talk about either our own research or other ideas we wanted to share with the group, always with lots of time for questions and discussion, and generous breaks for informal interaction. We also did a hike to Ñacuñán’s sand dunes, which was a nice opportunity to revisit field sites for some of us, and to see a representative part of the reserve for others. In the evening of the first day, there was time for tabletop games, and, for the younger members of the group for whom sleeping doesn’t seem to figure among their bodily needs, dancing. During lunch before our return to the city, we had an interesting exchange with the Reserve’s park rangers.

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Chañar (Geoffroea decorticans), one of the few tree species in Ñacuñán.

The setting of the retreat was great. Ñacuñán is a 12,000 ha Man and Biosphere Reserve located in eastern Mendoza Province, at the heart of the Monte desert. Although it can be quite hot in the summer, the winter is usually cold in the nights but lovely during the daytime, especially if sunny. The biological station consists of two houses, one for the Park Rangers and one for researchers, and a meeting room, which is sometimes also used as lab.

All in all, it was a great experience that will surely instill us with renewed energy to continue doing great ecological research.

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The retreat’s participants. From left to right: Ana Mazzolari, Natalia Schroeder, Hugo Marrero, Belén Maldonado, Julia Tavella, Guadalupe Peralta, Nydia Vitale, Ramiro Ovejero, Micaela Santos, Juan Manuel Drack, Luciano Cagnolo, Diego Vázquez and Jimena Dorado.

 

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Sharing lunch under the shade of algarrobo trees with the Reserve’s park rangers.

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Flower diversity and the reproduction of solitary bees

Post contributed by Jimena Dorado

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A female solitary bee Megachile leucographa building a nest in one of our wooden trap-nests.

A paper evaluating whether diverse flower communities favor pollinator reproduction just came out in PeerJ. This paper came out from my PhD thesis, in which I was mentored by Diego Vázquez. We had previously found that diverse flower communities are more stable in floral resource production along the flowering season, but the question of how the diversity and stability of resources affect pollinator reproduction remained open. You will find here some unexpected, intriguing results! Check it out!

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Grazing and the demography of a desert tree

Post contributed by Valeria Aschero

Valeria Aschero and Diego Vázquez working in Ñacuñán Biosphere Reserve. See Aschero et al. (2016) Forest Ecology & Management, Aschero et al. (2009) Austr. Ecol. and Vázquez et al. (2008) RSEA.

Valeria Aschero and Diego Vázquez working in Ñacuñán Biosphere Reserve. See Aschero et al. (2016) Forest Ecology & Management, Aschero et al. (2009) Austr. Ecol. and Vázquez et al. (2008) RSEA.

I have recently published a paper in Forest Ecology & Management aimed at studying how ungulates influence plant demography and population growth in different consecutive phases of their life cycle. For my PhD thesis (defended in 2011) I wanted to use a holistic approach to evaluate the demographic consequences of contrasting land use for the conservation of the desert tree Prosopis flexuosa (algarrobo dulce). One of the key things I had to learn for this project was how to use matrix population projection models, which gave me some headaches (I even had a dream in which I shared a cruise with the author of a renowned book on matrix models). This paper is the “cherry on the cake” of my PhD project, because it combines extensive observational and experimental data on the demography of P. flexuosa with matrix modeling to answer the question of how contrasting grazing regimes influence the demography and population growth of this species.

Publishing this paper would have never been possible without the cooperation of my coauthors (Bill Morris, Diego Vázquez, Juan Álvarez and Pablo Villagra), who have kindly and patiently supported me, understanding my single mother timing and my enthusiasm to get into new intellectual adventures!

You can see here the final version of the manuscript in the journal’s web site. (If you want the pdf of this paper and don’t have access to the journal, please send me an e-mail at vaschero [at] mendoza-conicet.gob.ar.)

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Welcome sabbatical visitors Gretchen LeBuhn and Mark Reynolds

gretchenamark_reynoldsGretchen LeBuhn, a Professor of Biology at San Francisco State University, and Mark Reynolds, a staff scientist with The Nature Conservancy, will be in our lab spending several months of their sabbatical. Gretchen is interested in plant evolutionary ecology and pollinator conservation. Mark works on biodiviersity conservation, particularly migratory birds. Welcome Gretchen and Mark!

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Abundance and generalization in mutualistic networks: a chicken-and-egg dilemma

fort_et_al_2015A paper evaluating the causal relationship between abundance and generalization in plant-animal mutualistic networks was published online today in Ecology Letters. This research was done in collaboration with Hugo Fort, a physicist in Uruguay, and Boon Leong Lan, a physicist in Malaysia. I’ve never met them personally (only electronically through a long series of e-mails and Skype discussions), but I hope we can get together one day to drink beers to celebrate the acceptance of our paper.

The story of this project is that Hugo was intrigued by the positive correlation between abundance and generalization in mutualistic networks (rare species tend to appear specialized, abundant species tend to appear generalized), and the unclear causal relationship between them. He had a clever idea to evaluate this relationship using basic principles of logical inference. He invited Leong and I to collaborate with him in addressing this question using his logical approach to analyze a database on plant-pollinator and and plant-frugivore networks. The analysis indicated that, if there is a causal relationship between abundance and generalization, it is that abundance causes generalization, not the other way around.

You can see here the final version of the manuscript, and here the pdf in the journal’s web site. (If you want this pdf and don’t have access to the journal, please send me an e-mail, dvazquez [at] mendoza-conicet.gob.ar.)

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Review on ecological and evolutionary impacts of chaning climatic variablity

vazquez_et_al_2015bA paper reviewing the ecological and evolutionary impacts of chaning climatic variability was published today in Biological Reviews. The idea for this paper started as informal chats with Ernesto Gianoli and Pancho Bozinovic during a course we taught in 2012 in Cuzco, Perú. We were all interested in changing climatic variability as one of the expected outcomes of climate change, and felt that there was a need for a synthesis on the ecological and evolutionary impacts of such changes. We later invited Bill Morris to contribute to the review, as he knows well the literature on the demographic and population-dynamic impacts of climatic variation.

You can see here the final version of the manuscript, and here the pdf in the journal’s web site. (If you want the journal pdf and don’t have access to the journal, please send me an e-mail, dvazquez [at] mendoza-conicet.gob.ar.)

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Back from our first group retreat in Vallecitos

The group listening to Nydia's talk on her past research.

The group listening to Nydia’s talk on her past research.

We are back from our first group retreat, which was held last week-end in the mountain shelter of the National University of Cuyo, in Vallecitos, Mendoza. During the retreat, each of us gave two talks, one on past research and another on ongoing, in-the-works research. In addition, we had time for a walk in the mountains and some dancing. A great experience that will help to make our group even more cohesive and interactive.

The group's members during the retreat in Vallecitos. From left to right: Natalia Schroeder, Diego Vázquez, Jimena Dorado, Micaela Santos, Ana Mazzolari, Hugo Marrero, Belén Maldonado, Nydia Vitale, Georgina Amico, Guadalupe Peralta.

The group’s members during the retreat in Vallecitos. From left to right: Natalia Schroeder, Diego Vázquez, Jimena Dorado, Micaela Santos, Ana Mazzolari, Hugo Marrero, Belén Maldonado, Nydia Vitale, Georgina Amico, Guadalupe Peralta.

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New grant to study structure and dynamics of ecological networks under global change

We just heard that Luciano Cagnolo (IMBIV, CONICET-UN Córdoba) and I got a grant from the National Agency for the Promotion of Science and Technology of Argentina to study the structure and dynamics of ecological networks under global change. This is great news, as it will allow us to fund the ongoing research within and between our labs.

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(Lack of) defensive role of ants throughout a broad latitudinal and elevational range of a cactus

Extra-floral nectaries of Opuntia sulphurea. Photo: Marina Alma.

Extra-floral nectaries of Opuntia sulphurea. Photo: Marina Alma.

Many plant species offer feeding resources (usually nectar) or nesting sites for ants, which in turn defend plants from herbivore attacks. With Marina Alma (former lab member), Rodrigo Pol (colleague at IADIZA) and Luis (Lucho) Pacheco (colleague at Universidad Mayor de San Andrés, La Paz, Bolivia) we observed ants visiting what seemed extra-floral nectaries in the cactus Opuntia sulphurea. This cactus species has a broad latitudinal distribution, from Mendoza in Argentina to La Paz in Bolivia; it also has a broad altitudinal distribution in the Andes. These facts led us to wonder about the outcome of the ant-plant interaction and its geographic variation: do ants visiting the extra-floral nectaries defend this plant species from insect herbivores, and does the outcome of this interaction vary throughout the geographic distribution of this plant species? We just published a paper in Biotropica reporting the results of a study (actually, Marina’s undergraduate thesis) evaluating this question. We conducted ant-exclusion experiments close to the southern (Mendoza) and northern (La Paz) latitudinal limits of O. sulphurea, and at two contrasting elevations. Our results indicate that ants do not benefit the plant in terms of herbivore damage or fruit and seed production, a result that was latitudinally and altitudinally consistent. Thus, this plant is apparently offering free meals for the ants, with no apparent benefit (nor detriment).

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