Genetically Engineered Organisms, Wildlife, and Habitat A Workshop Summary (2008) / Chapter Skim
Currently Skimming:
2 Current Research: What Is Known and What Are the Gaps?
2 Current Research: What Is Known and What Are the Gaps?
Pages 9-32
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 9... ...
They included people with primarily research, regulatory, or land management responsibilities; those who are involved in research and development of genetically engineered organisms (GEOs) in different taxa (plants, trees, microbes, insects, fish)
|
From page 10... ...
in farm fields and adjacent land; impacts on wildlife in farm fields; and impacts on wildlife in land adjacent to farm fields, such as grassland, forests, riparian areas, wetlands, or streams. Wildlife Food in Farm Fields and Adjacent Habitat According to Wolfenbarger, most relevant studies have focused on the abundance of wildlife food, particularly non-target and beneficial arthropods, in the presence or absence of a GE crop.
|
From page 11... ...
It is known that weed diversity and abundance affect wildlife food such as arthropods, so the effectiveness of the herbicide has implications for that food supply, noted Wolfenbarger. BOX 2-1 UK Farm Scale Evaluation: GE Crops at a Landscape Level From 1999 to 2004, a large study of the environmental impact of herbicide tolerant GE crops was conducted in the United Kingdom, known as the Farm Scale Evaluation (FSE)
|
From page 12... ...
Context, Wolfenbarger underlined, becomes key to the interpretation of the results. She added that an important knowledge gap remains in knowing how changes in wildlife food within and adjacent to farm fields will affect populations, species, and special or sensitive communities.
|
From page 13... ...
said despite this early activity, there is far more limited field experience with transgenic trees as compared to agricultural crops. The 363 notifications of field trials for transgenic trees have accounted for only 3 percent of total notifications to the Animal and Plant Health Inspection Service (APHIS)
|
From page 14... ...
Tsai noted that abundant outcrossing already exists in nature, and setting a baseline when studying the effects of GE trees is significant -- especially whether they would be planted in natural sites or, more likely, in plantations, on idle agricultural land, or even on waste sites as phytoremediation. Finally, she noted wildlife and natural habitats are in a constant state of flux, caused by climate change, human activities, and natural disasters.
|
From page 15... ...
In terms of regulatory limitations, she shared her belief that if conditional release beyond flowering or to the point of harvest remains unallowable, research cannot move forward. Institute for Forest Biotechnology Symposium on Genetically Engineered Forest Trees: A Workshop to Identify Priorities for Ecological Risk Assessment, May 3-4, 2007, Raleigh, NC; Institute for Forest Biotechnology Meeting on Growing Trees and Stemming Risks: Ecological Impacts Associated with the Products and Practice of Forest Biotechnology, March 19-21, 2006, Vancouver, Canada (Tree Genetics and Genomics Special Issue, April 2007)
|
From page 16... ...
Research on Effects of GE Fish -- Robert Devlin Since the 1980s, Robert Devlin (Fisheries and Oceans Canada) reported, more than 30 species of fish have been genetically engineered by transferring a wide range of genes related to metabolism, disease resistance, reproduction, and other purposes, with growth enhancement as the principal trait studied.
|
From page 17... ...
At a high level, this would involve looking at relevant components and processes in an ecosystem (using information on biotic and abiotic functions of aquatic ecosystems) ; the phenotype of the transgenic fish (including those traits the transgene intentionally altered, and those traits that emerged as "side effects" of the transgene on fish physiology or behavior)
|
From page 18... ...
Research Needs Devlin identified six research needs to study the effects of GE fish on the environment: • The development of large, variable-environment facilities to rear and assess transgenic fish in conditions that are as close to nature as possible. • Assessment of whether complicating gene-by-environment (G × E)
|
From page 19... ...
According to Allen, issues to think about when studying GE microorganisms include: horizontal gene transfer between microorganisms; the persistence of a GE microbe or its gene product in the environment; direct impacts on microbial populations through the creation of genetic bottlenecks; other direct effects, such as toxicity; and indirect impacts on an ecosystem through altered food webs, community structure, and nutrient cycling. Despite a large amount of literature about gene transfer between microbes, Allen said that not much is known about the outcomes of horizontal transfer or about indirect effects of the introduction of a new microbe, such as host-species shifts.
|
From page 20... ...
SOURCE: National Ecological Observatory Network, 2008. difficult to design experiments that look beyond direct toxicity effects to effects that move through the entire food web.
|
From page 21... ...
as either a source of wildlife food or as a predator on wildlife is not known, but as Wolfenbarger had suggested earlier, the impact of cotton cultivation itself might be more disruptive to the environment than the presence or absence of a transgenic insect. The regulatory concerns associated with the potential release of the transgenic bollworm are related to where in the bollworm genome the transgene is inserted, if the insertion is stable, the fitness effects from the insertion, and the possibility of horizontal gene movement.
|
From page 22... ...
Field Study A common goal across taxa is to conduct ecologically relevant studies in field settings. A few participants suggested that one potential approach for some species might be to partner with USGS and others to identify appropriate field sites where conditions and confinement are adequate.
|
From page 23... ...
bans, for example the use of transgenic insects in other countries, Allen suggested at least using these escapes as a learning opportunity. Along those same lines, another participant suggested making better use of currently grown GE crops to study ecological effects.
|
From page 24... ...
Tsai agreed the driving force to study ecological risk should be dealing with ecologically relevant traits, looking at the long term and in multiple sites. FUNDAMENTAL AND CROSSCUTTING RESEARCH FOR ASSESSING ECOLOGICAL EFFECTS OF GEOS As committee member Steven Strauss said in introducing the next plenary session on crosscutting issues, case-by-case study when looking at GEO organisms is necessary because of the diversity of traits, organisms, and environments.
|
From page 25... ...
According to Larson, other effects with potential application to GEO research include changes to native community structures, interactions with mutualists, relationships with other invasive species, changes in the availability and cycling of nutrients, ecosystem engineers, and predator-predator aggression (Table 2-2)
|
From page 26... ...
Larson closed with what she termed "nagging odds and ends" from invasion ecology that might apply to GEOs: • The lag times sometimes seen between the first introduction of a non-native species and their invasive effects can be long, even hundreds of years. • Invasions can be cryptic.
|
From page 27... ...
CURRENT RESEARCH 27 TABLE 2-2 Research of Effects of Invasions and Potential Parallels to GEOs Research Potential Application Effect Impacts Approaches to GEO Research Hybridization New genetic Modeling, Spread of gene combinations experimental via hybridization, that increase or crosses in leading to decrease fitness controlled settings persistence or loss of a native of gene population Changes to native Competition, Controlled Changes in trophic community apparent field and pot/ interactions, such structure competition, mesocosm as rapid growth, predation experiments, food replacement of or interaction web predators, or analysis herbivore resistance Interactions with Pollen quality or Manipulative or Effect of GE pollen, mutualists quantity effects observational pollen dispersal on native plants, field studies, to native relatives, parasitism of comparison of potential effects fungi mycorrhizal of root exudates colonization on soil mutualists, horizontal gene transfer Relationships Invasion cascades Observational Potential interactions with other or meltdowns field and lab/ that would facilitate invasive species greenhouse invasion by the other studies species Change in Changes in Nutrient Effects of GEOs availability/ litter quality or manipulation; on litter; changes cycling of quantity; changes observational in environmental nutrients in detritivore nutrient availability community or cycling Ecosystem Creation, Observational Potential effects, but engineering modification, studies, modeling also potential utility maintenance, or in restoration destruction of habitat Predator-predator One invader Observational; Potential for a aggression against another realistic habitat rapidly growing variation GEO to influence native species SOURCE: D Larson
|
From page 28... ...
Local events are most frequent, he said, but long-distance gene flow, harder to measure, also occurs. Gepts Gene or Trait -Source -Expression -Selective value -Genome location -Other Organism Environment -Plant or animal -Topography -Propagule and -Climate gamete dispersal -Wild or domesticated -Life cycle relatives -Reproduction -Pests & diseases -Other -Other FIGURE 2-1 Variables that may affect gene flow and persistence in the environment.
|
From page 29... ...
Finally, said Gepts, environmental factors affect gene flow. Throughout the world, areas that were once centers of crop domestication have wild and domesticated relatives in proximity to each other; even in the United States and Europe, where few agricultural crops originated, crops with close wild relatives can be found.
|
From page 30... ...
Thus, practical guidance from modeling suggests selecting indicator species with a higher trophic position, high rate of population growth, and low environmental sensitivity. A third approach is to look at the literature to consider other variables that integrate many ecological effects but do not rely on precise abundance estimates.
|
From page 31... ...
for areas 10 acres and more. Marvier said smaller field trials, such as those looking at pharmaceuticals, are harder to find out and may involve traits of particular concern.
|
From page 32... ...
Gepts suggested monitoring the wild relatives of crops, such as through GIS surveys, to see how they fare in the presence of transgenic crops. Larson said a matrix model may help predict potential invasive effects before a release is made, particularly in the area outside of a crop field.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.