Dispatches
2013; Wiley; Volume: 11; Issue: 5 Linguagem: Inglês
10.1890/1540-9295-11.5.228
ISSN1540-9309
AutoresESA,
ResumoIn April, civil society organizations from the Southern African Development Community (SADC), which represents 15 African countries, collectively condemned proposed laws that would restrict the rights of African farmers to save and freely trade their seeds. The groups are calling for rejection of the SADC draft Protocol for the Protection of New Varieties of Plants (Plant Breeders' Rights), saying it is modeled after the 1991 International Convention for the Protection of New Varieties of Plants, which they claim was created by – and addresses only the needs of – industrialized countries and does not consider the unique agricultural systems and economic challenges of Africa. The groups' concerns, representing those of millions of farmers in Africa and around the world, were submitted to the SADC Secretariat for consideration. Mariam Mayet, Founder and Director of the African Centre for Biosafety (Gauteng, South Africa), explains: “The SADC draft Protocol creates very strong protection for seed breeders and severely restricts what farmers may do with farm-saved seed. Because more than 80% of all seed in Africa is still produced and disseminated through ‘informal’ seed systems – that is, through on-farm seed saving and unregulated distribution between farmers – the Protocol's restrictions on farmers' rights will have far-reaching implications for this system and the food security that underpins it.” African farmers survive by saving and exchanging seeds. Should the SADC draft Protocol be ratified, patent-protected, genetically modified seed varieties would contaminate the market of informally exchanged native seeds, which have been traded without restraint by farmers across the continent for centuries. “One must understand that small farmers in Africa do not differentiate between corporate seed that comes into circulation and traditional varieties”, says Mayet, meaning all seed trade would be affected. According to the groups' submission, the Protocol could also prohibit the “unauthorized sale of seeds stored after harvesting a crop grown from the seeds of a protected variety” – a fear that was realized in the US in May, when the US Supreme Court ruled in favor of corporate giant Monsanto, which sued a farmer in Indiana for growing a soybean crop using seeds harvested from his previous patent-protected genetically modified crop without paying Monsanto an additional fee (Bowman v Monsanto Company [11–796]). If African farmers lose the right to freely trade their seeds they will become dependent on outside suppliers, which will then quickly make the seeds unaffordable to many farmers. This could be devastating to the countries within the SADC, which primarily consist of rural poor whose livelihoods depend on agriculture. American kestrels (Falco sparverius) appear to thrive in human-created areas like roadsides, where they can often be seen perching or hunting prey. Yet these highly disturbed areas may act as ecological traps by attracting birds to nest in them but decreasing their ability to reproduce, a new study finds (J Appl Ecol 2013; doi:10.1111/1365-2664.12103). The research suggests links between human-caused disturbance, stress, and decreased reproductive fitness, says Julie Heath, a coauthor of the study and an associate professor at Boise State University (Boise, ID). “Kestrels are perceived as a human-adapted species that does well in these areas. But there are a lot of noxious stimuli in anthropogenic environments. The birds may be more stressed than we realize”, Heath warns. The 2-year field study examined factors affecting the reproductive success of kestrels using established nest boxes in a variety of habitats in southwestern Idaho. Human disturbance, measured as proximity to noisy roads or developed areas, emerged as the most important factor. Female kestrels nesting in high-disturbance areas had higher levels of the hormone corticosterone –which has previously been linked to behavioral changes in birds, including nest abandonment – and were almost 10 times as likely to experience reproductive failure. Kestrels may choose to nest near human-disturbed areas because they appear to provide favorable habitat, with better prey availability and convenient perches, such as telephone poles, explains Erin Strasser, the study's lead author. However, when incubating eggs, these cavity-nesting birds are unable to see what's happening outside the nest and therefore rely on auditory cues to detect threats. Vehicle noise may create stress either directly or by masking natural cues, such as the alarm calls of other birds. Strasser points out that the study has implications for wildlife management in human-dominated areas. “We need to be very cautious about where we put our efforts”, she continues. “Land that appears to be good habitat may not be.” Ultimately, the researchers say, the most effective mitigation technique might be regulations or incentives to encourage engineering innovations that result in quieter vehicles or roads. Every year, wildfires burn, on average, more than 370 million ha of vegetation, damaging soils and rendering affected lands more vulnerable to flooding and erosion, which unleashes further degradation –sometimes so severe that soils never recover. Previous studies indicated that the higher the air temperatures soar during a blaze, the more destructive the soil impacts. But new research (Geophys Res Lett 2013; doi:10.1002/grl.50299) points to a counterintuitive, inverse effect: the hotter the fire – and the denser the vegetation feeding it – the less the underlying soil heats up. Earlier research on the subject has occurred mostly in laboratory settings or on small-scale field plots, according to Cathelijne Stoof, a soil and water scientist now at Cornell University (Ithaca, NY). To investigate real-world effects of fire on soils in varying terrain for her PhD at Wageningen University (Wageningen, the Netherlands), Stoof engineered an experiment at the 8.9-ha Valtorto watershed in north-central Portugal. The research team first mapped the watershed, which was largely covered by dense shrubs, and installed instruments for monitoring fire and soil-surface temperatures. In February 2009, the area was intentionally set afire, using methods designed to maximize the intensity of the fire under prevailing weather conditions. As expected, measurements collected during the burn showed that fire intensity was greatest in heavily vegetated areas. “But surprisingly, the soil surface in these places remained relatively cool – on average, 87°C – throughout the fire”, Stoof says. In contrast, soils in areas with less than about 60% plant cover averaged 188°C. “The relationship between fire intensity, the amount of vegetation present to fuel the fire, and the resulting soil temperatures held, regardless of changes in slope, solar exposure, elevation, and other factors”, she adds. Video imagery and other data indicated that in areas of greatest fire intensity, heat was transferred upward, driven by temperature differences between the ground and the flame-filled air. This, and the fact that the fire fronts attracted each other during the final stages of the fire event, allowed the fire to progress rapidly, heating the soil less. Also, while areas with dense plant cover fueled the blaze to higher flame temperatures, these locations were also moister, which further protected the soil. More studies are needed in other types of fire-prone areas, Stoof emphasizes. Nonetheless, “land managers conducting prescribed burns would do well to consider the variations in vegetation and moisture for the sake of minimizing soil damage”, she concludes. Jellyfish abundance appears to be increasing in many regions worldwide, and scientists are now beginning to understand the reasons for this trend. New work by researchers from the Institut de Recherche pour le Développement (Sete, France) examined how the overfishing of small pelagic (open-ocean) fish may be impacting jellyfish populations in upwelling systems in the northern Benguela Current off the western coast of Namibia and South Africa (Bull Mar Sci 2013; doi:10.5343/bms.2011. 1145). As lead author Jean-Paul Roux (Ministry of Fisheries and Marine Resources, Lüderitz, Namibia) explains, “There's an ongoing debate regarding the global trend [of increasing jellyfish populations] and the possible underlying causes, of which there are many.” A recent paper by Carlos Duarte et al. suggests that anthropogenic marine infrastructure may also be contributing to the growth of jellyfish populations by providing additional substrates for jellyfish polyps (Front Ecol Environ 2013; doi:10.1890/110246). Juvenile red jellies (Chrysaora fulgida) off Pelican Point, Walvis Bay, Namibia. Roux and his colleagues demonstrated that overfishing may benefit jellyfish in some ecosystems while adversely affecting other valuable resources, including economically important fish stocks and species of conservation concern. “The results of this [research] highlight the importance of small pelagic fish in the ecosystem function of upwelling ecosystems and that overfishing these species may trigger detrimental shifts that might not be easily reversible”, explains Roux. “In the case of [the northern] Benguela, overfishing small pelagic fish seems to have adversely affected the entire food web, benefiting jellyfish to the detriment of commercially valuable fish stocks and endangered predators like seabirds”. Mark Gibbons (University of the Western Cape, Bellville, South Africa), a coauthor of the paper, believes that jellyfish populations will remain high in the northern Benguela. “[Jellyfish] are not as efficient predators of zooplankton as [are] small pelagic fish, but their numbers are now having a significant impact (in space and time) on fish recruitment.” Given the high priority of sustainability in global fisheries, this work serves as a warning to managers of similar ecosystems. Roux concludes, “The next logical step is to refine our analyses and assess the potential for recovery of the northern Benguela ecosystem through modeling studies, to give the best possible advice for fisheries managers.” The acidity of the Arctic Ocean is on the rise, mirroring a worldwide increase of 30% found in surface ocean waters over the past 200 years and posing a host of challenges for an already stressed ecosystem, according to a new study, Arctic Ocean Acidification Assessment, released by the Arctic Monitoring and Assessment Programme. The primary driver behind the Arctic Ocean's increasing acidity is the absorption of carbon dioxide (CO2) emitted to the atmosphere by human activity, as per the report. The 60 scientists who coauthored the report also warned that the decreased pH will almost certainly result in substantial changes in Arctic marine ecosystems, with unknown consequences for economically important fish stocks and the livelihoods of indigenous people who depend on them. But it's too early to tell exactly how the changes will play out, particularly because of variations in other environmental factors in the region, including the loss of summer sea-ice cover, increased freshening of surface water from melting ice and land runoff, and increasing seawater temperatures. Decreases in the Arctic Ocean's summer ice cover increase the amount of open water available to absorb CO2, which accelerates acidification. Even the “simple” matter of increased acidity is not simple at all, says Howard Browman, a marine ecologist and principal research scientist at the Norwegian Institute for Marine Research (Bergen) and the lead author of the report's chapter on biological effects. “When people think of ocean acidification they imagine melting skeletons, but higher CO2 levels in the oceans can affect a range of physiological processes.” Some species will adapt while others will not, Browman adds, but elsewhere there may be surprises. As an example, Browman points out that although cold-water corals will be able to cope with increased acidity, the dead coral substrates that they grow on will tend to dissolve. Results from experiments with cod, herring, and Alaska walleye pollock suggest that these species have the ability to adapt to changing conditions, because they produce millions of eggs with highly variable phenotypes and genotypes. This range of variation means that “some individuals will have characteristics that will be well matched to the environment they find themselves in”, explains Browman. “Their life histories have evolved to include a lot of bet-hedging strategies.” The report was prepared at the request of the Arctic Council, an intergovernmental forum for the eight countries that contain Arctic territories, for consideration at their May meeting. Just how much water should be allowed to flow in the pristine Himalayan stretches of the Ganges River has become a bone of contention between the Government of India and environmental groups. Several hydroelectric power projects constructed in the river's upper reaches and tributaries have already affected its flow regime. Environmental and religious groups have opposed construction of new projects while also calling for decommissioning of existing ones. An Inter-Ministerial Group, set up by the Government in an attempt to resolve the dispute, recently recommended that new hydropower projects may be allowed if 20% to 50% of seasonal-dependent natural flows are retained. Furthermore, the group has suggested that existing and new projects alike should be redesigned to optimize energy generation during periods of high discharge. Environmental advocates and experts argue that establishing an arbitrary limit on water flow is unscientific and does nothing to restrict the development of new hydroprojects. “Having adversely hit aquatic diversity in India, dams not only cause hydrological changes and result in poor flows but also obstruct species migration, submerge habitats, and trap sediments. The mere fixing of a limit on environmental flows will not solve all of these problems”, points out Himanshu Thakkar (South Asia Network on Dams, Rivers and People, New Delhi, India). Historically, project developers have tended to split large hydroprojects into smaller ones in order to garner fiscal benefits and escape stringent environmental regulations while ignoring the dams' cumulative impact on the river, according to Sunita Narain (Centre for Science and Environment, New Delhi). Consequently, Narain suggests that national norms on ecological flow and minimum distance be maintained between hydroprojects on any river stretch. The Ganges was accorded status of a “National River” in 2008, but no steps have been taken since then to ensure its conservation. Indeed, two large projects close to the river's headwaters in the Himalayas were suspended but have yet to be decommissioned. “We need a river conservation law to prevent tinkering with the flow of the river, as well as to counteract downstream pollution and encroachments over its floodplains”, adds Hemant Dhyani (Ganga Ahvaan, Haridwar, India). Although the US is home to only 7% of the world's flora, new research indicates that several imperiled yet important plant species that are often considered “weeds” are found in the country. Many of these nondescript species are relatives of important food, forage, medicinal, or ornamental crops that contain valuable genetic traits –such as drought tolerance or disease resistance – that are increasingly sought after by plant breeders. In the journal Crop Science (2013; doi:10.2135/cropsci2012.10.0585), plant specialists detail the first inventory of crop wild relatives (CWRs) for the US, which includes 2495 taxa, representing 1905 species. Of these, 821 taxa related to 63 major agricultural crops, including relatives of sunflower, walnut, wild rice, raspberry, and plum, are considered priority species. Many of these species are threatened with extinction in the wild due to habitat loss, pollution, and climate change. CWRs are increasingly considered to be important sources of genetic material that could be exploited to help crops adapt to future climates. Until recently, however, little was known about the location and status of CWRs in the US. According to study author Colin Khoury, a PhD student at Wageningen University (Wageningen, the Netherlands), “This inventory is just the beginning; we're going to narrow down the list of species of greatest importance to food security and determine how to prioritize their conservation.” Government bodies concerned with plant conservation, such as the national germplasm repositories of the US Department of Agriculture, and land management agencies, including the US Forest Service (USFS) and Bureau of Land Management, can use the inventory to coordinate in situ and ex situ conservation strategies. Larry Stritch, a USFS botanist (Washington, DC), expects the inventory to bolster the service's ongoing efforts to identify and manage plant species found in national forests and grasslands. For example, a 1011-ha chiltepin pepper preserve – dubbed the Wild Chile Botanical Area – in the Coronado National Forest outside Tucson, AZ, is home to one wild species of chiltepin pepper that is the progenitor of hundreds of types of sweet and hot peppers. Surprisingly, non-native species make up 12% of the CWR inventory and almost 5% are considered noxious weeds. While there is little incentive to protect non-native species, they too have value to plant breeders; for example, wild relatives of beets in California are salt tolerant. The goal is to collect and maintain such species in gene banks so that any unique combination of genetic traits is available to plant breeders, says Khoury Researchers investigating how herbivores coexist in alpine environments have discovered an unexpected interaction between collared pikas (Ochotona collaris), a small alpine-dwelling mammal, and Arctic woolly bear moth (Gynaephora groenlandica) caterpillars. “In our field experiment, we found that pikas preferentially collected plants for their hay piles in areas that had been previously grazed by caterpillars”, explains lead author Isabel Barrio (University of Alberta, Edmonton, Canada). “This interaction might create herbivory hotspots”, she suggests, “and might, therefore, have implications for the local plant community”. Barrio and her colleagues constructed three 1-m2 experimental plots in each of 10 pika hay-foraging territories. They added two G groenlandica caterpillars to one experimental plot in each territory to increase invertebrate herbivory, sprayed another plot in each territory with a biological insecticide that is innocuous to mammals to reduce invertebrate herbivory, and sprayed the final, control plot with a similar volume of water. Pika herbivory – quantified by examining two dominant plant species that exhibit clear signs of grazing by pikas – was found to be highest in the plots with increased invertebrate herbivory (Biol Lett 2013; doi:10.1098/rsbl.2013.0090). A Gynaephora groenlandica caterpillar. “This is a valuable paper”, comments ecologist Erik Beever (US Geological Survey, Bozeman, MT), “but because pikas are generalist herbivores, it's unclear from the results presented whether the pikas simply switched their dietary preferences in the increased invertebrate herbivory plot or changed their overall level of herbivory”. “The experimental design of this study and its main conclusion are solid”, agrees plant ecologist Christa Mulder (University of Alaska Fairbanks). “However, without knowing the mechanism through which pika consumption increased, it's difficult to know whether the caterpillar–pika interaction will have an effect on ecosystem processes. Information on whether the pikas ate more of one, the other, or both of the dominant plant species in the increased invertebrate herbivory plot would give insights into the mechanism”, she suggests. “We have several hypotheses for the mechanism underlying the caterpillar–pika interaction but no data as yet to support any of them”, admits Barrio. But, she says, “this summer, we intend to examine whether invertebrate herbivory increases the palatability of plants for pikas and to investigate the effect of caterpillar frass [solid excrement] on nutrient cycling.” Groupers are suffering serious overfishing, according to a report published in Fish and Fisheries (2013; 14: 119–36, doi:10.1111/j.1467-2979. 2011.00455.x) – and the chances of recovery look slim. The report, entitled Fishing Groupers Towards Extinction: A Global Assessment of Threats and Extinction Risks in a Billion Dollar Fishery, prepared by members of the International Union for Conservation of Nature Species Survival Commission's Grouper and Wrasse Specialist Group, indicates that at least 20 grouper species (some 12% of all groupers) are at risk of extinction if current trends continue. A further 22 species (13%) are listed as “Near Threatened”. The numbers speak for themselves. According to the United Nations Food and Agriculture Organization, over 275 000 metric tons of grouper were taken in 2009, 25% more than in the late 1990s, and a staggering 17 times the 1950 take. Estimates place the number of individual fish currently harvested per year at over 90 million. “Grouper numbers are dropping at an incredibly fast rate due to overfishing and a lack of management policies in most grouper fisheries”, says report coauthor Matthew Craig (University of San Diego, CA). “Furthermore, groupers are taken to supply the growing luxury seafood market in Hong Kong and China.” And luxury it is, with diners paying over US$200 per kilogram. “This creates a huge demand that cannot be met with the available supply.” A gaping grouper off Australia's northeast coast. Groupers do not live in large shoals, and cannot therefore be hunted en masse like herring or cod – at least, that is, until they spawn. Many grouper species gather to mate in huge numbers at predictable times and places, the females spilling their eggs into the sea and the males dashing upward, racing through the egg cloud and depositing their sperm as they go. The Caribbean's Nassau grouper (Epinephelus striatus), which is fished during these aggregations, has practically disappeared, and the squaretail coralgrouper (Plectropomus areolatus) of the Pacific and the seas around Southeast Asia now faces the same fate. Furthermore, the area over which groupers are being taken is becoming ever larger in order to supply the lucrative Asian market. Unfortunately, groupers require several years to become sexually mature, leaving them unable to replace their losses. “In addition to improvements in public awareness, we need better management and enforcement of regulations”, says Craig. “Otherwise, overfishing means the prognosis for grouper recovery is poor, putting the livelihoods of those who depend on stable fisheries at risk.” European buckthorn (Rhamnus cathartica), an invasive plant often used for decorative purposes in the US, is the newest addition to the ever-growing list of causes of amphibian population decline, according to a new study scheduled for publication in an upcoming issue of Journal of Herpetology. Buckthorn releases emodin – a chemical compound that adversely affects local amphibian populations –in large amounts during springtime leaf production. Unfortunately, western chorus frogs (Pseudacris triseriata) lay their eggs in early spring, usually overlapping the time when buckthorn shrubs begin to produce their leaves. Amphibian egg maturation is disrupted by even small amounts of emodin in frog breeding pools, often causing malformations or preventing egg hatching. The western chorus frog population is classified as decreasing by the International Union for Conservation of Nature's Red List but still falls under the “Least Concern” category, making the species a good test subject for how emodin specifically affects amphibians. Allison Sacerdote-Valet, a reintroduction biologist for the Lincoln Park Zoo (Chicago, IL) and lead author of the study, believes that this chemical plays a larger role in amphibian declines than previously thought. “Studies have been performed on birds, mammals, and even moths but until now none have looked at the effect that emodin has on adult frogs, much less on their egg maturation”, she explains. “If you see hatching disruptions and poor recruitment in a more common species like the western chorus frog, then you have to wonder what is happening to rare or threatened amphibians?” Sacerdote-Valet has also found that western chorus frogs are much more sensitive to the chemical than the first species her team looked at, the African clawed frog (Xenopus laevis). European buckthorn appears to favor the wetlands of the US Midwest and grows in extremely dense stands, making eradication a costly and time-consuming task. To remedy this, Sacerdote-Valet suggests, “Reaching out to the community is the best and easiest way to stop the progression of European buckthorn. If people want to continue to see natural wildlife, it is important to let them know that that wildlife is in danger.”
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