201 research outputs found
The Introduction of thousands of tonnes of glyphosate in the food chain - an evaluation of glyphosate tolerant soybeans
Glyphosate-tolerant (GT) soybeans dominate the world soybean market. These plants have triggered increased use of, as well as increased residues of, glyphosate in soybean products. We present data that show farmers have doubled their glyphosate applications per season (from two to four) and that residues of late season spraying of glyphosate (at full bloom of the plant) result in much higher residues in the harvested plants and products. GT soybeans produced on commercial farms in the USA, Brazil and Argentina accumulate in total an estimated 2500–10,000 metric tonnes of glyphosate per year, which enter global food chains. We also review studies that have compared the quality of GT soybeans with conventional and organic soybeans. Feeding studies in Daphnia magna have shown dose-related adverse effects (mortality, reduced fecundity and delayed reproduction) of glyphosate residues in soybeans, even at glyphosate concentrations below allowed residue levels. We argue that GT soybeans need to be tested in fully representative and realistic contexts. However, the current risk assessment system has only required and received data from field trials with beans that were sprayed with much lower doses of glyphosate as compared to contemporary commercial farms. This has left knowledge gaps and a potentially serious underestimation of health risks to consumers.publishedVersio
The competitive edge of an invading specialist
The following article, Bøhn, T. & Amundsen, P.-A. (2001). The competitive edge of an invading specialist. Ecology, 82(8), 2150-2163, can be accessed at https://esajournals.onlinelibrary.wiley.com/journal/19399170. Copyright by the Ecological Society of America.Introduced species represent major threats to native and natural biodiversity. On the other hand, biologists may increase the understanding of ecological interactions by following communities during establishment of exotic species. Accordingly, feeding ecology and habitat use were studied in native whitefish (Coregonus lavaretus) and recently invading vendace (C. albula) in two lake localities situated 50 km apart within the subarctic Pasvik River system, northern Norway and Russia. Whitefish originally dominated the native fish communities of both lakes. The recent invasion and successive downstream expansion of vendace allowed comparisons between two sites: one in which the influence of the new potential competitor on the native fish species was weak, and one in which the influence was strong. In the downstream lake vendace was recorded for the first time at the time of the study, and only in small numbers, whereas in the upstream lake vendace had established a high population density and was the dominant fish species in the pelagic zone. No vertical segregation in pelagic habitat use was found between the two fish species in either lake. In the downstream lake both whitefish and vendace fed exclusively on zooplankton and had almost identical diets. In the upstream lake, in contrast, whitefish fed predominantly on zoobenthos and surface insects, while vendace fed mainly on zooplankton. Thus, the strong presence of vendace as a specialized planktivore reduced the availability of zooplankton as prey for the more generalist whitefish. The food segregation between the two fish species in the upstream lake was apparently interactive and caused by a strong asymmetrical competition for zooplankton, vendace being the superior species. The ecological consequences (including reduced zooplankton size and species diversity, alteration of the pelagic food web, and eutrofication as a possible cascading effect on the primary production) of the vendace invasion in the Pasvik watercourse are considerable, even after a few years, and are likely to proceed and intensify in the future
Glyphosate: too much of a good thing?
Source at http://dx.doi.org/10.3389/fenvs.2016.00028 Although previously accepted as the less toxic alternative, with low impact on animals,
farmers as well as consumers who are exposed to residues in food, glyphosate chemicals
are now increasingly controversial as new evidence from research is emerging. We
argue that specific aspects of the history, chemistry and safety of glyphosate and
glyphosate-based herbicides should be thoroughly considered in present and future
re-evaluations of these dominant agrochemicals:
• Glyphosate is not a single chemical, it is a family of compounds with different chemical,
physical, and toxicological properties.
• Glyphosate is increasingly recognized as having more profound toxicological effects
than assumed from previous assessments.
• Global use of glyphosate is continuously increasing and residues are detected in food,
feed, and drinking water. Thus, consumers are increasingly exposed to higher levels
of glyphosate residues, and from an increasing number of sources.
• Glyphosate regulation is predominantly still based on primary safety-assessment
testing in various indicator organisms. However, archive studies indicate fraud and
misbehavior committed by the commercial laboratories providing such research.
We see emerging evidences from studies in test-animals, ecosystems indicators and
studies in human health, which justify stricter regulatory measures. This implies revising
glyphosate residue definitions and lowering Maximum Residue Limits (MRLs) permissible
in biological material intended for food and feed, as well as strengthening environmental
criteria such as accepted residue concentrations in surface waters. It seems that
although recent research indicates that glyphosates are less harmless than previously
assumed and have complex toxicological potential, still regulatory authorities accept
industry demands for approving higher levels of these residues in food and feed
Clone- and age-dependent toxicity of a glyphosate commercial formulation and its active ingredient in Daphnia magna.
This article is part of Marek Cuhra's doctoral thesis which is available in Munin at http://hdl.handle.net/10037/7869Low levels of glyphosate based herbicide
induced significant negative effects on the aquatic invertebrate
Daphnia magna. Glyphosate herbicides such as brands
of Roundup, are known to be toxic to daphnids. However,
published findings on acute toxicity show significant discrepancies
and variation across several orders of magnitude.
To test the acute effects of both glyphosate and a commercial
formulation of Roundup (hereafter Roundup), we conducted
a series of exposure experiments with different clones and
age-classes of D. magna. The results demonstrated EC50 (48)
values in the low ppm-range for Roundup as well as for the
active ingredient (a.i.) isopropylamine salt of glyphosate
(glyphosate IPA) alone. Roundup showed slightly lower
acute toxicity than glyphosate IPA alone, i.e. EC50 values of
3.7–10.6 mg a.i./l, as compared to 1.4–7.2 mg a.i./l for
glyphosate IPA. However, in chronic toxicity tests spanning
the whole life-cycle, Roundup was more toxic. D. magna
was exposed to sublethal nominal concentrations of 0.05,
0.15, 0.45, 1.35 and 4.05 mg a.i./l for 55 days. Significant
reduction of juvenile size was observed even in the lowest
test concentrations of 0.05 mg a.i./l, for both glyphosate and
Roundup. At 0.45 mg a.i./l, growth, fecundity and abortion
rate was affected, but only in animals exposed to Roundup.
At 1.35 and 4.05 mg a.i./l of both glyphosate and Roundup,
significant negative effects were seen on most tested
parameters, including mortality. D. magna was adversely
affected by a near 100 % abortion rate of eggs and
embryonic stages at 1.35 mg a.i./l of Roundup. The results
indicate that aquatic invertebrate ecology can be adversely
affected by relevant ambient concentrations of this major
herbicide. We conclude that glyphosate and Roundup toxicity
to aquatic invertebrates have been underestimated and
that current European Commission and US EPA toxicity
classification of these chemicals need to be revised
Detecting rare gene transfer events in bacterial populations
This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permissio
On the numerous concepts in invasion biology
Source at https://doi.org/10.1007/s10530-005-0710-6.The study of biological invasions has triggered the production of a diversity of concepts. The terminology has, however, often been applied inconsistently and inaccurately. This article lists and assesses the most commonly used terms and concepts in invasion ecology. In each case the most coherent definition and use is suggested
Insufficient risk assessment of herbicide-tolerant genetically engineered soybeans intended for import into the EU
The introduction of herbicide-tolerant (HT) genetically engineered (GE) soybeans has raised new challenges for the European risk assessment of imported food and feed. Food and feed products derived from these plants may show specific patterns of chemical residues and altered nutritional composition. Furthermore, there has been a substantial increase in the usage of herbicides in soybean production due to the emergence of resistant weeds. This concerns particular glyphosate-based herbicides and also other herbicides. In this review, we give an overview of available data regarding glyphosate application on HT GE soybeans in North and South America. We have further compared this data with herbicide applications in experimental field trials conducted by the industry. We conclude that field trials carried out for risk assessment purposes do not generally represent the real agronomic conditions in commercial HT GE plant cultivation. In most cases, neither the applied dose nor the number of applications match real conditions. This finding is especially relevant for risk assessment since a review of relevant publications shows that the amount and timing of spraying glyphosate as a complementary herbicide onto HT GE plants can impact their composition; this is relevant to EFSA comparative risk assessment of GMOs. Further, closely related issues were identified that overlap with EU GMO and pesticide regulation, but are not currently considered. These issues concern indirect, cumulative and combinatorial effects as well as the assessment of mixed toxicity. Consequently, current risk assessment practice for HT GE plants cannot be considered to fulfil EU regulatory standards which require the safety of food and feed to be demonstrated. It is much more likely that concerns about the health risks of HT GE plant material used for food and feed have been underestimated. We therefore conclude that the EU risk assessment of food and feed derived from HT GE plants needs substantial improvement.publishedVersio
Prey consumption rates and growth of piscivorous brown trout in a subarctic watercourse
This is the peer reviewed version of the following article: Jensen, H., Amundsen, P.-A., Elliott, J.M., Bøhn, T. & Aspholm, P.E. (2006). Prey consumption rates and growth of piscivorous brown trout in a subarctic watercourse. Journal of Fish Biology, 68(3), 838-848, which has been published in final form at https://doi.org/10.1111/j.0022-1112.2006.00972.x. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Prey consumption rates of piscivorous brown trout Salmo trutta were studied in the Pasvik watercourse, which forms the border between Norway and Russia. Estimates of food consumption in the field were similar to or slightly less than maximum values from a bioenergetic model. The piscivore diet consisted mainly of vendace Coregonus albula with a smaller number of whitefish Coregonus lavaretus. Individual brown trout had an estimated mean daily intake of c. 1·5 vendace and 0·4 whitefish, and a rapid annual growth increment of 7–8 cm year−1. The total population of brown trout >25 cm total length was estimated as 8445 individuals (0·6 individuals ha−1), giving a mean ± s.e. annual consumption of 1553880 ± 405360 vendace and 439140 ± 287130 whitefish for the whole watercourse. The rapid growth in summer of brown trout >25 cm indicated a high prey consumption rate
Complex Outcomes from Insect and Weed Control with Transgenic Plants: Ecological Surprises?
Agriculture is fundamental for human survival through food production and is performed in ecosystems that, while simplified, still operate along ecological principles and retain complexity. Agricultural plants are thus part of ecological systems, and interact in complex ways with the surrounding terrestrial, soil, and aquatic habitats. We discuss three case studies that demonstrate how agricultural solutions to pest and weed control, if they overlook important ecological and evolutionary factors, cause “surprises”: (i) the fast emergence of resistance against the crop-inserted Bt-toxin in South Africa, (ii) the ecological changes generated by Bt-cotton landscapes in China, and (iii) the decline of the monarch butterfly, Danaus plexippus, in North America. The recognition that we work with complex systems is in itself important, as it should limit the belief in reductionist solutions. Agricultural practices lacking eco-evolutionary understanding result in “surprises” like resistance evolution both in weeds and pest insects, risking the reappearance of the “pesticide treadmill”—with increased use of toxic pesticides as the follow-up. We recommend prioritization of research that counteracts the tendencies of reductionist approaches. These may be beneficial on a short term, but with trade-off costs on a medium- to long-term. Such costs include loss of biodiversity, ecosystem services, long-term soil productivity, pollution, and reduced food quality
Behavioural responses of wild anadromous Arctic char experimentally infested in situ with salmon lice
Salmon lice can impact the marine behaviour, growth, and survival of salmonids, but little is known about their effects on Arctic char. We present
behavioural responses from the first dose-response experiment with wild anadromous Arctic char (n = 50) infested in situ with salmon lice
(0.0–1.2 lice g−1 fish) in an area with low natural infestations. Infested fish spent less time at sea (mean ± SD = 22 ± 6 d) than non-infested
fish (mean ± SD = 33 ± 5 d), and a significant dose response was evident, with even very low louse burdens (−1 fish) reducing the
marine feeding time. Furthermore, a negative correlation was present between time spent close to their native watercourse and parasite burden,
suggesting that salmon lice influence the marine habitat use of Arctic char. No impact of salmon lice was evident on the return probability, i.e.
marine survival. However, the presence of louse-induced mortality cannot be excluded as the modest sample size was only sufficient to detect
extreme effects. Reduced marine feeding time and altered marine habitat use will likely have substantial negative effects on growth and fitness,
suggesting that impacts of salmon lice must be considered in the conservation of anadromous Arctic char
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