Algemeen

Waarschuwingen over de mogelijke rol van milieuverontreiniging met neonicotinoiden bij sterk dalende populaties van vogels, kikkers, egels, vleermuizen en andere insectenetende dieren zijn niet ver gezocht en moeten serieus worden genomen

Imidacloprid werd gevonden in 89% van watermonsters die werden genomen in agrarische gebieden van Californië, en in 19% van de monsters werd de maximaal toegestane concentratie van 1,05 microgram / L, zoals vastgesteld door Environmental Protection Agency (EPA), overschreden. In Nederland kwam imidacloprid in meetbare hoeveelheden voor in 30% van de 4.852 watermonsters die door Waterschappen werden verzameld tussen 1998 en 2007. Deze cijfers geven aan dat er inmiddels een wijdverbreide besmetting is van het oppervlaktewater met zeer langzaam afbreekbare (persistente) systemische insecticiden. Het eerste gevolg van deze besmetting is de geleidelijke vermindering, en mogelijk het verdwijnen van hele populaties van aquatische geleedpotigen in de getroffen gebieden. Aangezien de tijd de bepalende variabele bij dit proces is, kan er van worden uitgegaan dat, wanneer deze verontreiniging zich de komende jaren in het huidige tempo voortzet, de biodiversiteit en de functionaliteit van vele aquatische ecosystemen ernstig zal worden aangetast. Omdat deze organismen bovendien een primaire bron van voedsel voor een groot aantal soorten van gewervelde dieren zijn (bijv. vissen, kikkers en vogels), zal de uitputting van hun belangrijkste voedselbron onvermijdelijk indirecte effecten hebben op deze dierlijke populaties. Het geval van de patrijs (Perdix perdix) in Engeland is een voorbeeld van hoe een combinatie van herbiciden en insecticiden indirect de ondergang van een soort kan veroorzaken door de teloorgang van onmisbare voedselbronnen. Daarom zijn waarschuwingen over de mogelijke rol van milieuverontreiniging met neonicotinoiden bij de sterk dalende populaties van vogels, kikkers, egels, vleermuizen en andere insectenetende dieren niet ver gezocht en moeten serieus worden genomen.

Warnings about the possible role of environmental contamination with neonicotinoids in steeply declining populations of birds, frogs, hedgehogs, bats and other insectivorous animals are not far fetched and should be taken seriously

Imidacloprid was detected in 89% of water samples in agricultural areas of California, with 19% exceeding the US Environmental Protection Agency’s chronic invertebrate Aquatic Life Benchmark of 1.05 μg/L. In the Netherlands, imidacloprid appeared in measurable quantities in 30% of the 4,852 water samples collected between 1998 and 2007. These figures indicate there is already a widespread contamination of waterways and estuaries with persistent systemic insecticides. The first consequence of such contamination is the progressive reduction, and possible elimination, of entire populations of aquatic arthropods from the affected areas. As time is a critical variable in this type of assessment, it is envisaged that should this contamination continue at the current pace over the years to come the biodiversity and functionality of many aquatic ecosystems will be seriously compromised. Secondly, as these organisms are a primary food source of a large number of vertebrates (e.g. fish, frogs and birds), the depletion of their main food resource will inevitably have indirect impacts on the animal populations that depend on them for their own survival. The case of the partridge in England is an example of how a combination of herbicides and insecticides can bring the demise of a non-target species by indirectly suppressing its food requirements. Therefore, warnings about the possible role of environmental contamination with neonicotinoids in steeply declining populations of birds, frogs, hedgehogs, bats and other insectivorous animals are not far fetched and should be taken seriously.

Von den 19 Reptilienarten in der Schweiz sind 80% gefährdet

Höchste Zeit also, entsprechende Schutz- und Fördermassnahmen einzuleiten und den Kenntnisstand über das Reptilienvorkommen zu vervollständigen. Die Kantone Obwalden und Zug rufen die Bevölkerung zur Mithilfe auf. Reptilien haben hohe Ansprüche an ihren Lebensraum und können deshalb gut als Indikatoren für die Qualität unserer Natur- und Grünräume herangezogen werden. Deshalb stehen an Orten mit starker Gefährdung auch Tiere und Pflanzen mit ähnlichen Ansprüchen unter Druck. Obwohl alle Reptilienarten – dazu zählen neben den Schlangen zählen auch Eidechsen, Blindschleichen und Schildkröten - in der Schweiz gesetzlich geschützt sind, ist die Gefährdungszahl erschreckend hoch. Die Ursachen sind vielseitig, jedoch ist besonders die Zerstörung und Zerschneidung der Lebensräume für diesen Rückgang verantwortlich. Dadurch ist der genetische Austausch unter der Population nicht mehr gewährleistet, was die lokale Gefährdung beschleunigt. Heute sind Reptilien aufgrund der Bautätigkeiten an vielen Standorten u.a. durch Nutzungsänderungen oder den Ausbau der Verkehrsnetze bedroht. Auch die intensive Landwirtschaft mit vermehrtem Einsatz von Kunstdüngern und Pestiziden setzt den Reptilien und ihrer Nahrung zu.

The Pacific leatherback turtle population has experienced a catastrophic decline over the past two decades and might be on the verge of extirpation

The Pacific leatherback turtle (Dermochelys coriacea) population has experienced a catastrophic decline over the past two decades and might be on the verge of extirpation. The most conservative population estimates, derived from nest counts and numbers of females nesting annually, show that there could be as few as 2,300 adult females in the Pacific Ocean. Others have proposed estimates of 1,690 adult females in the Eastern Pacific and 2,100–5,700 breeding females in the Western Pacific. The progressive decline in numbers of nesting females in the Eastern Pacific, well documented at Playa Grande, Costa Rica, and on the Pacific coast of Mexico, has been attributed to increased adult mortality associated with gillnet and longline fisheries and extensive egg harvesting. In the Western Pacific, declines in nesting females have been documented in Papua, Indonesia and Terengganu, Malaysia, where the nesting population virtually has collapsed as a result of intensive egg harvesting. Although consistent long-term nesting data are not available for most of the Western Pacific leatherback population, major nesting areas for leatherbacks recently have been identified, and conservation efforts to protect and monitor these sites are underway.

Postmortem Diagnostic Investigation of Disease in Free-Ranging Marine Turtle Populations

Over the past few decades, there have been increasing numbers of reports of diseases in marine turtles. Furthermore, in recent years, there have been documented instances of apparently new diseases emerging in these species of which the etiology and/or pathogenesis remain unknown. These instances i) raise concern for the survival of marine turtles, and ii) question the health and stability of the benthic marine environments in which turtles live. Knowledge of common disease processes and pathologic changes in lesions, along with a standardized approach to postmortem and sample collection are required to document and
understand the host-agent-environment interactions in marine turtle health. This review combines, for the first time, a standardized approach to the postmortem of marine turtles for veterinary clinicians, with a concurrent descriptive review of the gross and microscopic pathologic changes in lesions commonly seen.

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.

De sterke achteruitgang van de gladde slang in Nederland sinds de jaren 1970

Het verspreidingsgebied van de gladde slang (Coronella austriaca) in Nederland omvatte ooit grote delen van de hogere zandgronden. Het zwaartepunt van de verspreiding ligt tegenwoordig op de Veluwe. Voor 1971 komt de soort verspreid over de hoge zandgronden (met uitzondering van de duinen) van Nederland voor. Veel heideterreinen en hoogveengebieden zijn bezet. In Zuid-Limburg is de soort aanwezig op de Sint Pietersberg en het Vijlenerbosch en omgeving nabij Vaals. Van 1971 tot 1995 valt, met uitzondering van de twee grootste kerngebieden (Veluwe en Drenthe-Friesland), een sterke achteruitgang in de verspreiding te constateren. In deze periode is de soort voor het laatst vastgesteld op de Utrechtse Heuvelrug. De laatste waarneming dateert van 1971 en komt uit de omgeving Hilversum/Bussum. Rond die tijd verdwijnt in Gelderland de gladde slang ook definitief ten oosten van de Veluwe uit de landgoederenzone rond Brummen (Leusveld en Voorstonden). Uit Overijssel worden na 1970 nauwelijks nog gladde slangen gemeld. Er zijn waarnemingen uit het Zeesserbosch ten zuiden van Ommen (1985) en Hengelerheurne ten oosten van Oldenzaal (1976). Van het Wierdense Veld zijn ook in deze periode bevestigde waarnemingen bekend. Op de Brunssummerheide en omgeving na is de soort uit Zuid-Limburg verdwenen. Van 1996 tot 2007 heeft een verdere achteruitgang in de verspreiding plaatsgevonden en verschillende deelpopulaties zijn verdwenen of geïsoleerd geraakt. De Veluwe vormt nog steeds het belangrijkste kerngebied met 30 grotendeels aaneengesloten bezette uurhokken. Het Drents-Friese grensgebied met onder andere het Fochteloërveen en het Dwingelderveld vormt de andere grote verspreidingskern.

Loggerhead sea turtle lawsuit

Conservation groups have sued the Obama administration in San Francisco to protect the habitat of the loggerhead sea turtle (Caretta caretta), a long-migrating, 250-pound reptile that is being depleted by fishing and water pollution. The government placed the Pacific loggerhead on the endangered-species list in September 2011 and was legally required to designate critical habitat within a year, said the suit, filed Tuesday in U.S. District Court. The Pacific turtles swim 7,000 miles between nesting areas in Japan and feeding grounds off Southern California and Mexico, and occasionally venture into Bay Area waters. The suit also seeks habitat protection for the Atlantic loggerhead, which nests in Florida and is listed as a threatened species.

Lying in Wait for Extinction: Ecological Correlates of Conservation Status among Australian Elapid Snakes

Why do some species decline rapidly with anthropogenic disturbance, whereas others readily exploit disturbed habitats? It is possible that the ecological characteristics of some species render them especially vulnerable to extinction. Previous analyses of a diverse array of taxa have identified a number of intrinsic ecological predictors of vulnerability, but snakes have not been studied in this respect. We collated ecological data on Australian venomous snake species in the family Elapidae, based primarily on examination of preserved specimens in museums, to investigate possible differences between threatened and nonthreatened taxa. We also used comparative ( phylogenetically based) analyses to identify functional associations with endangerment. Correlates of conservation vulnerability identified in previous studies did not discriminate successfully between threatened and nonthreatened elapid species. However, threatened and nonthreatened elapids differed significantly in two main respects.