Algemeen

World's Reptile Populations Running Thin

Reptiles worldwide may be under greater environmental stress than their amphibian cousins, according to a report published in the journal BioScience. Amphibian declines have garnered much attention within the scientific community over the last 10 years. Declines of reptiles, often linked to amphibians, warrant attention on their own, the authors note. "Recent research has demonstrated that amphibians are declining on a global scale," said Whit Gibbons, a herpetologist and professor of ecology at the University of Georgia and lead author of the study. "We wanted to examine the same kind of evidence for reptiles as no one had yet synthesized the information to see if reptiles are facing similar problems." According to the researchers, government records show that reptiles are vanishing faster than amphibians. More reptiles face environmental problems based on the numbers of endangered and threatened species identified by the U.S. Fish and Wildlife Service, they point out. The Wildlife Service lists 26 species of amphibians and 88 species of reptiles under the Endangered Species Act. Likewise, the World Conservation Union lists 129 amphibians and more than 270 reptiles around the world as endangered or vulnerable.

Amphibian and reptile declines over 35 years at La Selva, Costa Rica

Amphibians stand at the forefront of a global biodiversity crisis. More than one-third of amphibian species are globally threatened, and over 120 species have likely suffered global extinction since 1980. Most alarmingly, many rapid declines and extinctions are occurring in pristine sites lacking obvious adverse effects of human activities. The causes of these “enigmatic” declines remain highly contested. Still, lack of long-term data on amphibian populations severely limits our understanding of the distribution of amphibian declines, and therefore the ultimate causes of these declines. Here, we identify a systematic community-wide decline in populations of terrestrial amphibians at La Selva Biological Station, a protected old-growth lowland rainforest in lower Central America. We use data collected over 35 years to show that population density of all species of terrestrial amphibians has declined by ≈75% since 1970, and we show identical trends for all species of common reptiles. The trends we identify are neither consistent with recent emergence of chytridiomycosis nor the climate-linked epidemic hypothesis, two leading putative causes of enigmatic amphibian declines.

Gefahr durch Pestizide für Frösche weitgehend unterschätzt

Aktuelle Untersuchung an sieben zugelassenen Mitteln zeigt bei Grasfröschen Sterblichkeitsraten von 20 bis 100 Prozent.
Der Kontakt mit Pflanzenschutzmitteln kann für Frösche tödlich sein - wie gefährlich die Gifte teilweise für die Amphibien sind, wurde bisher aber offenbar unterschätzt. Eine aktuelle deutsche Studie hat nun aufgedeckt, dass schon der Einsatz der empfohlenen Produktmenge bei Grasfröschen (Rana temporaria) zu Sterblichkeitsraten von 20 bis 100 Prozent führt. Die Gefahr besteht für alle sieben getesteten Mittel - ob Fungizid, Herbizid oder Insektizid. Zugelassen sind sie trotzdem, da das entsprechende Verfahren bislang mögliche Auswirkungen auf Amphibien (Lurche) nicht untersucht. "Es ist kaum fassbar, dass es bei Pestiziden, die das aktuell praktizierte Zulassungsverfahren für Pestizide durchlaufen haben, zu direkter Mortalität bei Amphibien kommt", sagt Carsten Brühl, Leiter der Studie des Instituts für Umweltwissenschaften an der Universität Koblenz-Landau. "Unsere Laborversuche zeigen eine derartige Wirkung auf an Land lebende Entwicklungsstadien der Tiere. Dieser in der Risikobewertung bislang nicht berücksichtigte Effekt sollte in den Schutzbemühungen von Frosch- und Krötenpopulationen Berücksichtigung finden."

"Pesticiden kunnen kikkers binnen het uur doden"

Nieuw onderzoek veronderstelt dat pesticiden en andere chemicaliën een significante rol spelen in de wereldwijde achteruitgang van amfibieën. Dat schrijft de Britse krant The Guardian. De wetenschappers achter de studie zeggen dat het zowel "verbazingwekkend" als "alarmerend" is dat veelvoorkomende pesticiden zo giftig kunnen zijn, en dat in dosissen die goedgekeurd zijn door overheden. De onderzoekers uiten ook kritiek op hoe de pesticiden getest worden. "Je zou niet denken dat producten, die geregistreerd zijn op de markt, zo'n giftig effect hebben", zegt Carsten Brühl van de Duitse universiteit Koblenz-Landau. "Het is het simpelste effect dat je je kan inbeelden: je spuit de pesticide op de amfibie en die sterft. Dat moet zich vertalen in een dramatisch effect op gehele populaties."

New research suggests pesticides are playing a significant and previously unknown role in the global decline of amphibians

Widely used pesticides can kill frogs within an hour, new research has revealed, suggesting the chemicals are playing a significant and previously unknown role in the catastrophic global decline of amphibians. The scientists behind the study said it was both "astonishing" and "alarming" that common pesticides could be so toxic at the doses approved by regulatory authorities, adding to growing criticism of how pesticides are tested. "You would not think products registered on the market would have such a toxic effect," said Carsten Brühl, at the University of Koblenz-Landau in Germany. "It is the simplest effect you can think of: you spray the amphibian with the pesticide and it is dead. That should translate into a dramatic effect on populations." Trenton Garner, an ecologist at the Zoological Society of London, said: "This is a valuable addition to the substantial body of literature detailing how existing standards for the use of agricultural pesticides, herbicides and fertilisers are inadequate for the protection of biodiversity."

Henk Tennekes speaks at Hampshire Beekeepers Association Convention

The HBA Convention was held, as in previous years, at Barton Peveril College, Eastleigh, near Southampton on 10th November 2012. Confronting environmental issues 'head on' we had speakers on systemic pesticides, Genetically Modified crops and global warming! With the recently published results of research undertaken in both France and Scotland pointing to detectable effects of sub-lethal levels of systemic insecticides on the nervous systems of pollinators, we were fortunate in having as a speaker Henk Tennekes, an independent toxicologist and one of the founders of http://www.smallbluemarble.org.uk a charity supporting independent research into systemic insecticides, who presented his findings on neonicotinoid insecticides and species decline. ‘His blunt, evidence based presentation was very stimulating and pulled no punches delivering the ‘chilling’ message that neonicotinoids, targeted at insects attacking plants also affected bees and other insects collecting pollen and nectar.’ It was shocking to discover how toxic and persistent these chemicals are and that they are water soluble and leach through soil to affect many arthropods and invertebrate species and so affect a wide range of animals, including humans, higher up ‘the food chain’. ‘Henk’s relevant and thought provoking presentation made a strong impression on all those present and whether or not we agreed with all his conclusions it certainly made one want to learn more about neonicotinoids’. His lecture is attached (The Italian Union of Beekeepers' Associations [Unaapi - Mieliditalia] is distributing this lecture in Italian, see below. Maria Jose Pastor Rodriguez of Unaapi - Mieliditalia prepared a Spanish translation of the lecture, attached). Hampshire BKA has a Proposition before BBKA ACM recommending the notification of neonicotinoid-treated seed sowing to raise awareness and enable monitoring of effects on colony health and mortality. ’We should all take action to make the public aware of this problem’’.

The contribution of increasing UV radiation and environmental contamination to the global decline of amphibian populations

As part of an overall ‘biodiversity crisis’, many amphibian populations are in decline throughout the world. Numerous factors have contributed to these declines, including habitat destruction, pathogens, increasing ultraviolet (UV) radiation, introduced non-native species and contaminants. In this paper we review the contribution of increasing UV radiation and environmental contamination to the global decline of amphibian populations. Both UV radiation and environmental contaminants can affect amphibians at all life stages.

Wind-borne agrochemicals may be an important factor in declines of the federally threatened California red-legged frog

The federally threatened California red-legged frog (Rana aurora draytonii) has disappeared from much of its range for unknown reasons. We mapped 237 historic locations for the species and determined their current population status. Using a geographic information system (GIS), we determined latitude, elevation, and land use attributes for all sites and analyzed the spatial pattern of declines. We then compared the observed patterns of decline to those predicted by the climate change, UV-B radiation, pesticides, and habitat alteration hypotheses for amphibian decline. Declines were not consistent with the climate change hypothesis but showed a strong positive association with elevation, percentage upwind agricultural land use, and local urbanization.

Pestizide − eine Gefahr für die biologische Vielfalt

In Deutschland sind 70 Prozent der natürlichen Lebensräume bestandsgefährdet, zwei Drittel der Amphibien- und Reptilienarten als gefährdet eingestuft oder vom Aussterben bedroht, 30 Prozent der Farne und Blütenpflanzen sind bestandsgefährdet. Ebenso stehen zwei Drittel der Tier- und Pflanzenarten des Offenlandes auf den Roten Listen der bedrohten Arten. In Deutschland ist für die Erhaltung der biologischen Vielfalt insbesondere die Art und Weise der praktizierten Landwirtschaft ausschlaggebend, fast die Hälfte der Landesfläche ist Agrarfläche (Europäische Union: 43 Prozent). Die nationale Biodiversitätsstrategie trägt dieser Bedeutung Rechnung, Ziele zur Erhöhung des Anteils an Grünland oder Streuobstwiesen wurden vereinbart. Die Zusagen aber werden nicht eingehalten. Die Landwirtschaft in der Bundesrepublik muss, um einen signifikanten Beitrag zur Sicherung der Biodiversität zu leisten, im Rahmen einer Agrarwende weg von der intensiven Landwirtschaft hin zu einer nachhaltigen extensiven Landwirtschaft transformiert werden. Dies beinhaltet eine umfassende Veränderung der Art zu wirtschaften, speziell aber den Stopp des Einsatzes von chemisch-synthetischen Pestiziden.

Pesticides are instrumental in declines of amphibians

Several species of anuran amphibians have undergone drastic population declines in the western United States over the last 10 to 15 years. In California, the most severe declines are in the Sierra Mountains east of the Central Valley and downwind of the intensely agricultural San Joaquin Valley. In contrast, coastal and more northern populations across from the less agrarian Sacramento Valley are stable or declining less precipitously. In this article, we provide evidence that pesticides are instrumental in declines of these species.