Algemeen

During the past 50 years, the human population has more than doubled and global Agricultural production has similarly risen. However, the productive arable area has increased by just 10%; thus the increased use of pesticides has been a consequence of the demands of human population growth, and its impact has reached global significance. Although we often know a pesticide´s mode of action in the target species, we still largely do not understand the full impact of unintended side effects on wildlife, particularly at higher levels of biological organization: populations,
communities, and ecosystems. In these times of regional and global species declines, we are challenged with the task of causally linking knowledge about the molecular actions of pesticides to their possible interference with biological processes, in order to develop reliable predictions about the consequences of pesticide use, and misuse, in a rapidly changing world.

Florida’s birdlife is some of the most captivating and well-recognized in the country, from impossibly pink Roseate Spoonbills to the raucous gulls and terns of our sandy beaches. At the start of the 20th century, many Florida bird species were in steep decline because of exploitation for the millinery trade. Their bright, ornate feathers were highly prized as decoration for women’s hats. Most of these bird populations rebounded after the federal government banned this practice , yet today many of these birds are again threatened and decreasing. They face pressures on where they live and competition for the food they eat. Habitat loss is often the emphasis of bird conservation efforts, but comprehensive conservation of any species must consider all its vulnerabilities. Forage fish—sometimes known as baitfish or prey fish—play a vital role in the marine ecosystem as a food source for coastal birds and other marine wildlife. These small, nutrient-rich fish are the crucial link between plankton and predators in the ocean food webs. The schooling behavior and relative abundance of forage fish make them ideal prey for much larger coastal predators such as Terns, Pelicans, and Ospreys, as well as their ocean counterparts such as tarpon, snook, and dolphins. In this report, we investigate an area of growing concern for these birds: how declines in populations of forage fish in Florida’s coastal waters could exacerbate declines of seabirds, wading birds, and other fish-eating birds, particularly species of conservation concern such as Least Terns (Sternula antillarum, formerly Sterna antillarum) and Black Skimmers (Rynchops niger)

The full ramifications of the changes will not be known for some time, the annual general meeting of the Action for the River Kennet (ARK) conservation group heard. The meeting took place in the Hungerford Corn Exchange on Thursday, November 7. More than 60 ARK members heard that the pollution incident continued to cause major environmental changes. The pollution was first discovered on July 1 by ARK volunteer riverfly monitors. Subsequent investigations by the Environment Agency (EA) revealed the culprit was a lethal insecticide identified as chlorpyrifos. As little as a few teaspoonsful are thought to have entered the watercourse from a water treatment works in Marlborough, Wiltshire, leading to a 15km stretch of water down to Hungerford being affected. The River Kennet is of England’s finest chalkstreams. The incident is one of the largest ever and wiped out insect life – a major source of food for fish and other wildlife – in around a third of the river. The meeting heard that brown trout and other fish in the river appear ill-equipped for winter following the disastrous chemical spill. ARK director Charlotte Hitchmough said the entire base of the food chain has been removed, causing fish to alter their diets. She added: “They are partly eating more terrestrial invertebrates, smaller fish and even small crayfish". Delegates heard that, while large fish appear to coping at the moment, smaller fish stocks have been greatly reduced. This, in turn, could have a knock-on effect as there are fewer small fish for the large fish to eat.

Die Untersuchung geht darauf zurück, dass die kantonale Angelfischerstatistik für die Jahre 1990 bis 2006 einen steten Rückgang der Fische auswies – bei Bachforellen beträgt er 80 Prozent. Weil Fische als ausgezeichnete Indikatoren für den Zustand der Umwelt gelten, waren die Behörden durch diese Zahlen alarmiert. Durchgeführt haben die Untersuchung Personen aus dem kantonalen Fischereiinspektorat, dem Amt für Wasser und Abfall, der Eidgenössischen Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz (Eawag), der Vogelwarte Sempach, Forscher der Universitäten Bern und Lausanne und weitere Partner. Sie untersuchten die Aare zwischen dem Auslauf des Thunersees bis zum Übergang in den Wohlensee bei Bremgarten bei Bern sowie ihre Zuflüsse. Dies in den Jahren 2009 bis 2012. Ein Hauptaugenmerk galt der Bachforelle.

Starfish are dying in massive numbers due to a disease outbreak that melts the animals into a white goo, leaving researchers scrambling to explain the troubling phenomenon. Dubbed Sea Star Wasting Syndrome, the disease is most prominent on the Pacific Coast, ranging from Southern California to Alaska, where at least 10 species of sea stars have reportedly been afflicted. According to the Associated Press, up to 95 percent of sea star populations in some tide pools have been killed. While major sea star die-off was documented in Southern California in the 1980s and 1990s, the current outbreak, which causes lesions, tissue decay and eventual loss of limbs, is unprecedented. “We've never seen it at this scale up and down the coast,” Pete Raimondi of the University of California Santa Cruz told the Santa Rosa Press Democrat. “They essentially melt in front of you.”

A new paper is calling for more attention to be paid to poorly-known micro-organisms capable of killing off amphibians and fishes. Chytridiomycosis, caused by the amphibian chytrid fungus, affects the skin of amphibians, is capable of killing rapidly, and is responsible for population declines and extinctions in amphibians globally. Not surprisingly, it is the most well-studied disease in amphibians. But it’s not the only fungal or ‘fungal-like’ disease out there. One particular group of fungal-like parasites called mesomycetozoeans (what is it with fungi and difficult to pronounce names!?) are very poorly-studied parasites capable of causing high mortality rates in fish and amphibian populations. Mesomycetozoeans are microscopic, but can cause visible lesions on skin, muscle or internal organs in amphibians and freshwater fishes, and these infections can kill. Although we don’t know much about them, several aspects of the biology of mesomycetozoeans are particularly worrying. They are highly virulent (deadly!) under certain conditions, aren’t at all fussy about which species they infect (even jumping from fish to frog, for example), and have a free-living infectious stage. Together, these characteristics make them possible candidates for causing the extinction of their host species, just like the better-known amphbian chytrid fungus.

A report released in late October by the California Department of Fish and Wildlife shows a decline in the abundance of fish in the San-Joaquin Sacramento Delta. The Fall Mid Water Trawl indices measure the relative abundance and distribution of upper estuary pelagic species. Unlike a population count, the indices sample 122 stations from upstream San Pablo Bay to Stockton in September and October by towing a midwater trawl through the water for 12 minutes. All fish, shrimp and jellyfish collected are identified and enumerated. This year’s indices reveal that populations of Delta fish such as Delta smelt, striped bass and threadfin shad are at a fraction of their historical abundance. Striped bass in particular have plummeted since the 1980s, with the 23 counted in this year’s report the second lowest figure since the trawls began in 1967.

Angling and fishery organisations have welcomed an announcement from the UK's Natural Environment Minister Richard Benyon that plans are being drawn up to remove products containing the dangerous insecticide Chlorpyrifos from domestic sale. Mr Benyon was responding to strong representations from the Angling Trust, the national representative body for anglers, and fishery owners along the Kennet Valley in Wiltshire and Berkshire following last month's devastating pollution of all invertebrate life along a 15 kms stretch of this famous chalk stream by a tiny amount of chlorpyrifos which entered the river via the combined sewerage system. In a recent letter to Mr Benyon Angling Trust campaign chief Martin Salter wrote: “Experience from other countries as well as the catalogue of environmental disasters caused by chlorpyrifos, of which the upper Kennet is but the latest, must surely tell us that the current controls are simply not fit for purpose." In fact the Angling Trust wants to know why a lethal chemical like chlorpyrifos is allowed to be used anywhere near a river or watercourse. Apparently the 15 kms wipeout of invertebrates between Marlborough and Hungerford may have been caused by as little as a couple of spoonfuls and was almost certainly the result of an irresponsible domestic disposal. "We hope you will agree that the the sooner we follow the lead of Singapore and America and ban the domestic use of chlorpyrifos the better off our rivers will be.”

Built on a fragile balance of predators and prey, Australia's various ecosystems are highly susceptible to change. When human intervention consistently alters an ecosystem, this balance can be upset, seriously threatening the biodiversity. While all species are important to an ecosystem, 'keystone' species are particularly vital. These are often top predators such as crocodiles, because of the role they play in controlling prey. The southern cassowary, however, is also a keystone species as it spreads the seeds of as many as 238 species of plants in northern Queensland. "Importantly, research clearly shows that biodiversity contributes significantly to our survival, well-being and enjoyment of life, so when we lose species at the rates that we're currently witnessing, we should be gravely concerned," says Dr Euan Ritchie an ecologist at Deakin University in Melbourne. "Losing any one species is a tragedy, but what is even more concerning is the loss of a species' ecological role following its extinction," says Euan. "If we were to lose dingoes, as an example, we also lose their ability to control pest species such as foxes and cats, and overabundant herbivores, [like] pigs, goats and kangaroos, which has widespread and often negative impacts across the whole system."