lunes, 26 de noviembre de 2018
LA CRISIS CLIMÁTICA VISTA DESDE LA PERSPECTIVA AGROECOLÓGICA
LA CRISIS CLIMÁTICA VISTA D... by on Scribd
domingo, 25 de noviembre de 2018
sábado, 24 de noviembre de 2018
Organic farming at local and landscape scales fosters biological pest control in vineyards
Lucile Muneret Arthur Auriol Denis Thiéry Adrien Rusch
Lucile Muneret Arthur Auriol Denis Thiéry Adrien Rusch
While organic farming practices, which are often promoted as models of ecological intensification, generally enhance biodiversity, their effects on the delivery of ecosystem services, such as biological pest control, are still unknown. Here, using a multi‐scale hierarchical design in southwestern France, we examined the effects of organic farming and seminatural habitats at the local and landscape scales on biological control services of three pests, including weeds and insects, in 42 vineyards. Organic farming at the local and landscape scales was beneficial to the mean and temporal stability of biological control services, while the proportion of seminatural habitats in the landscape reduced the level of biological pest control potential. The effects of organic farming and seminatural habitats across spatial scales varied with the type of prey considered and with time. Egg moth removal rates were higher in fields under organic management compared to conventional management while weed seed removal rates increased with the proportion of organic farming in the landscape. Larval removal rates as well as seed removal rates were always more stable within time in organic fields than in conventional fields. Moreover, independently of farming system type, local variables describing the agricultural management intensity, such as pesticide use or crop productivity, were also found to be important variables explaining levels of biological control services. Pesticide use tended to reduce biological control potential, while crop productivity was associated with contrasting biological control responses depending on the pest type. Our study demonstrates the need to target multiple spatial scales and to consider farming practices, as well as the proportion of seminatural habitats, to design functional landscapes that optimize biological pest control services.
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viernes, 23 de noviembre de 2018
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Therefore, we attempt-to treat the same problem with several alternative models each with different simplifications but with a common biological assumption. Then, if these models, despite their different assumptions, lead to similar results we have what we can call a robust theorem which is relatively free of the details of the model. Hence our truth is the intersection of independent lies.
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Richard Levins. 1966. The strategy of model building in population biology.
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Richard Levins. 1966. The strategy of model building in population biology.
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lunes, 19 de noviembre de 2018
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Aelian (175- 235 CE). On the characteristics of animals.
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The inhabitants of Thessaly, of Illyria, and of Lemnos regard jackdaws as benefactors and have decreed that they be fed at the public expense, seeing that jackdaws make away with the eggs and destroy the young of the locusts which ruin the crops of the aforesaid people. The clouds of locusts are in fact considerably reduced and the season's produce of these people remains undamaged.
Aelian (175- 235 CE). On the characteristics of animals.
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domingo, 18 de noviembre de 2018
sábado, 17 de noviembre de 2018
viernes, 16 de noviembre de 2018
'Facts' don't give scientists a monopoly on the truth
by Wayne Linklater
Andrea Byron, leader of the National Science Challenge for Biological Heritage, recently wrote: "I am not debating the facts. 1080 is safe to use."
Such statements from scientists harden, rather than resolve, the
environmental conflict over 1080's use. They are paraded by one side as
the "scientific truth" and decried by the other as misleading. Each side
accuses the other of falsehoods, and the conflict worsens.
Scientists' assurances about 1080's "safety" aren't helpful because
they are expressions of their personal and cultural values, not the
"facts" that they pronounce them to be.
How poisonous 1080 is, and what and how many animals are killed, can be
measured and established as a fact. But to conclude that 1080 is
"safe", scientists must interpret those facts subjectively, in ways that
are influenced their values and beliefs.
It
is normal to mix factual information with our cultural values and
beliefs – we all do it. The problem arises when scientists pretend they
do not.
Like
old-fashioned religious leaders, when scientists make authoritative
statements about the safety of tools, like 1080, Roundup, and
genetically modified wildlife, they are behaving as if they have
infallible knowledge from a higher power. But instead of an imaginary
God, their higher power is science and its imagined objectivity.
Take, for example, the promotion of 1080 as "moderately humane".
If we could measure how much pain an animal experiences when poisoned
with 1080, then it might get a middling score, say 5 out of 10.
The personal values of some scientists have led them to interpret that score as good, and supporting 1080's use, because they value protecting biodiversity over eliminating animal suffering.
But someone who is more concerned about animal cruelty could use the
same score to conclude that 1080's use is unacceptable. After all, any
poison that is moderately humane must also be moderately inhumane.
Both are legitimate and reasonable arguments using the same facts. Neither is incorrect.
It is the same for 1080's safety. A more risk-sensitive person than
Dr Byron would conclude that 1080 is not safe enough. Both are
interpreting the same facts, but with a different set of values and
priorities. They are both sensible arguments.
Putting aside the false information from some on both sides, the 1080 debate is not a conflict over facts.
Whether discussing the safety or humaneness of 1080, Roundup, or
genetic engineering, and all the other environmental conflicts that fill
our news, it is people's different values and cultures that are the
source of disagreement.
On this Dr Byron and I agree: "People make decisions and form opinions based on their personal values, belief systems, and world views." What she failed to do was acknowledge that this is true of scientists too.
We scientists could contribute more constructively to environmental
debates if we acknowledged the part played by our own subjectivity and
values.
Instead, unfortunately, scientists have a tendency to inflame debate by
accusing others of allowing subjectivity to cloud their judgment. In
her writing, Dr Byron described the pro-1080 and science community as
applying "reason and logic in decision-making" – implying that the anti-1080 community was irrational.
This science "facts rational" v "values irrational" framing is a common
error by the pro-1080 community, especially among scientists, and it is
understandably interpreted as insulting by others.
So long as we erroneously claim to be "right" because we use facts, and
others "wrong" because they use values, we will continue to fuel
environmental conflicts.
Science and scientists can provide us with more reliable information
but they cannot, and should not, impose their values on others from
pulpits of scientific authority – behaving like high-priests of the
truth.
Science and scientists have been used to justify polluting industries,
cigarettes, DDT, and nuclear weapons, to name a few of many. It is
right, therefore, for citizens to be critical of science and scientists,
and the values they mix with facts when they make pronouncements about
the "truth".
It is naive to think that these environmental debates can be solved by
scientists and science. Instead, we resolve them by sitting down
together to respectfully speak and hear about our different values,
beliefs and cultures. Then we engage in some good old-fashioned
person-to-person negotiation to find a way for both sides to be part of
the solution.
Only then are scientific information and scientists most useful – values first, facts second.
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