sábado, 9 de diciembre de 2017

In the very earliest time
When both people and animals lived on earth
A person could become an animal if he wanted to
and an animal could become a human being.
Sometimes they were people
and sometimes animals
and there was no difference.
All spoke the same language
That was the time when words were like magic.
The human mind had mysterious powers.
A word spoken by chance might have strange consequences.
It would suddenly come alive
and what people wanted to happen could happen--
all you had to do was say it.
Nobody could explain this:
That's the way it was.
-- Nalungiaq, Inuit woman interviewed by ethnologist Knud Rasmussen in the early twentieth century.

"...A few years ago, I was entering a restaurant very near my home and noticed a sign in front that said "Native Grass Garden-Do Not Disturb." My first response, naturally, was to trample over to the sign to see what the fuss was about. I knelt down and admired the soft, variegated green foliage, the tiny pointed leaves and small yellow and orange flowers. Suddenly it occurred to me that these were exactly the same plants that I had been mowing down on my John Deere sit-down mower the day before...but I had been thinking of them as "weeds"! This was a lesson in the power of labels, of the trances induced by the word-worlds that are enacted every time someone categorizes in speech or thought. 

Is this a question of "mere semantics" as some might argue? The plants remained "the same" regardless of any label I might apply in this view. But the effect in the real world was as tangible as in Nalungiaq's story where what people said came to be. Having labeled the plants in my yard "weeds," I mowed them down. The "native grasses" at the neighboring restaurant remained untouched because a conservation-minded gardener had, by contrast, elevated them to a place of respect with his label. 

Among indigenous peoples, the concept of "weed" does not exist. Every plant has a purpose or it would not be here. The entire field of ethnobotany consists of attempts to articulate in western terms the web of life as it is perceived through native eyes and the categories of native languages. Comparative ethnobotany reminds us that the Linnaean system of categorization is but one of an infinite number of possible taxonomies available to humankind. The categories we use in our everyday speech and thinking, like the formal categories of Linnaeaus for plants, are inherited as part of socialization and constitute in large measure a collective sense of "reality." In the view being advanced here, language always mediates experience in some measure. Yet the path of least resistance is to accept the habitual categories in lieu of the complexities of experience. Language creates reality rather than merely describes it as the First Peoples still remember..." 


miércoles, 6 de diciembre de 2017

DNA metabarcoding data unveils invisible pollination networks      

André Pornon, Christophe Andalo, Monique Burrus & Nathalie Escaravage

Animal pollination, essential for both ecological services and ecosystem functioning, is threatened by ongoing global changes. New methodologies to decipher their effects on pollinator composition to ecosystem health are urgently required. We compare the main structural parameters of pollination networks based on DNA metabarcoding data with networks based on direct observations of insect visits to plants at three resolution levels. By detecting numerous additional hidden interactions, metabarcoding data largely alters the properties of the pollination networks compared to visit surveys. Molecular data shows that pollinators are much more generalist than expected from visit surveys. However, pollinator species were composed of relatively specialized individuals and formed functional groups highly specialized upon floral morphs. We discuss pros and cons of metabarcoding data relative to data obtained from traditional methods and their potential contribution to both current and future research. This molecular method seems a very promising avenue to address many outstanding scientific issues at a resolution level which remains unattained to date; especially for those studies requiring pollinator and plant community investigations over macro-ecological scales.

Bipartite pollination networks built from visit surveys (Nobs, right panels) and metabarcoding (Nseq, left panels) data. (a,b) Plant-pollinator groups; (c,d) plant-pollinator species; (e,f) individual pollinator-plant species (Empis leptempis pandellei as an example of pollinator species). Line thickness highlights the proportion of interactions. Apis: Apis mellifera; Bomb.: Bombus sp.; W.bee: wild bees; O.Hym.: other Hymenoptera; O.Dipt.: Other Diptera; Emp.: Empididae; Syrph.: Syrphidae; Col.: Coleoptera; Lep.: Lepidoptera; Musc.: Muscidae.


sábado, 2 de diciembre de 2017

Spatial diversification of agroecosystems to enhance biological control and other regulating services: An agroecological perspective. 

Hatt S, Boeraeve F, Artru S, Dufrêne M, Francis F. 

Spatial diversification of crop and non-crop habitats in farming systems is promising for enhancing natural regulation of insect pests. Nevertheless, results from recent syntheses show variable effects. One explanation is that the abundance and diversity of pests and natural enemies are affected by the composition, design and management of crop and non-crop habitats. Moreover, interactions between both local and landscape elements and practices carried out at different spatial scales may affect the regulation of insect pests. Hence, research is being conducted to understand these interdependencies. However, insects are not the only pests and pests are not the only elements to regulate in agroecosystems. Broadening the scope could allow addressing multiple issues simultaneously, but also solving them together by enhancing synergies. Indeed, spatial diversification of crop and non-crop habitats can allow addressing the issues of weeds and pathogens, along with being beneficial to several other regulating services like pollination, soil conservation and nutrient cycling. Although calls rise to develop multifunctional landscapes that optimize the delivery of multiple ecosystem services, it still represents a scientific challenge today. Enhancing interdisciplinarity in research institutions and building interrelations between scientists and stakeholders may help reach this goal. Despite obstacles, positive results from research based on such innovative approaches are encouraging for engaging science in this path. Hence, the aim of the present paper is to offer an update on these issues by exploring the most recent findings and discussing these results to highlight needs for future research.