Libellen

Systemic insecticides decreased dragonfly abundance in Japan

Since the mid-1990s, populations of the common Japanese dragonfly Sympetrum frequens in rice fields have declined severely. Application of systemic insecticides—especially fipronil—to nursery boxes of rice seedlings is suspected to be the main cause of the decline. However, until now there have been insufficient population data to test the causality. We conducted a dragonfly survey from 2009 to 2016 in four prefectures of Japan and compiled the data to enable the comparison of population growth rates along five main census routes over the years.

Bayer attempts to discredit peer-reviewed study showing its products caused a Japan fishery to collapse

The May 2019 newsletter of the Saitama Ecosystem Conservation Society describes how, before the introduction of neonicotinoids in the 1990s, numberless brilliant red akiakane or autumn darter dragonflies could be seen around rice fields in the fall. Experiments by Japanese dragonfly expert Tetsuyuki Ueda of Ishikawa Prefectural University showed how the pesticides reduced the number of surviving dragonfly nymphs to a small fraction, and that the chemicals persist for years in the soil of rice paddy fields.

Fipronil application on rice paddy fields eliminates dragonfly nymphs

Several reports suggested that rice seedling nursery-box application of some systemic insecticides (neonicotinoids and fipronil) is the cause of the decline in dragonfly species noted since the 1990s in Japan. We conducted paddy mesocosm experiments to investigate the effect of the systemic insecticides clothianidin, fipronil and chlorantraniliprole on rice paddy field biological communities.

Damselflies are being harmed by thiacloprid

Damselfly populations are being harmed by insecticides as researchers find the wildlife scourge of neonicotinoids continues to grow. Some chemicals in this group have already been banned by the EU but thiacloprid is still in widespread use. Similar chemicals in the neonicotinoid family have already been tied to severe decline in bee populations and now it appears the damage is more widespread.

Wildlife species in danger of disappearing from East Anglia

Experts from Suffolk Wildlife Trust, Buglife and the RSPB have all pointed to species in danger of disappearing from East Anglia. They include stone curlew - only 202 pairs nested in the East of England last year; the shrill carder bee - common in the region 25 years ago but now found only in the Thames Gateway area; and the crested cow-wheat - a plant limited to a small number of roadside verges because grassland has disappeared to farming or construction. Indeed, habitat destruction and human disturbance are cited as the two most common reasons these species are on the brink.

Minister stuurt rapport insectensterfte naar Tweede Kamer

De insectensterfte in Duitse natuurgebieden was veel in het nieuws vorig najaar. In opdracht van Minister Schouten van LNV is er nu een rapport verschenen over de uitkomsten van dat onderzoek, de vergelijkbaarheid met de Nederlandse situatie, de kennis over de trends bij Nederlandse insecten en de mogelijke oorzaken. Vlinder- en libellenmeetnetten vormen een belangrijke bron voor dit rapport.

In de rapportage worden vier onderzoeksvoorstellen geformuleerd die nodig zijn voor een integrale aanpak van de problemen:

Groene glazenmaker ging in een jaar tijd met 90 procent achteruit in de Krimpenerwaard

Afgelopen zomer bleek uit tellingen in de Krimpenerwaard een zeer sterke achteruitgang van de groene glazenmaker (Aeshna viridis): maar liefst 90 procent vergeleken met 2016. Deze zeldzame en beschermde libel is gebonden aan sloten met krabbenscheer. Om nog onbekende reden werd deze plant in 2017 vroeg bruin in de Krimpenerwaard.

Wo die Libellen schwirren, ist die Welt in Ordnung

Biologin Sandra Bischoff vom Nabu Oldenburg beschäftigt sich seit fast zehn Jahren mit Libellen und anderen Insekten. Am Dienstag, 14. November, will sie mit ihrem Vortrag „Libellen vor der Haustür“ im Huder Rathaus den Zuhörern diese besonderen Insekten näher bringen. Das Insektensterben ist derzeit in aller Munde. Auch die Libellen sind stark gefährdet. Von den 81 Arten stehen laut Bischoff bereits 42 auf der Roten Liste. In unserer Region sind 76 Arten aus neun Familien anzutreffen. Die einen fallen auf, weil sie sehr groß sind, andere sieht man kaum.

Comparative ecotoxicity of imidacloprid and dinotefuran to aquatic insects in rice mesocosms

In this study, effects of two neonicotinoid insecticides, imidacloprid and dinotefuran, on aquatic insect assemblages were evaluated in experimental rice mesocosms. During the 5-month period of the rice-growing season, residual concentrations of imidacloprid were 5–10 times higher than those of dinotefuran in both soil and water. Imidacloprid treatment (10 kg/ha) reduced significantly the populations of, Crocothemis servilia mariannae and Lyriothemis pachygastra nymphs, whereas those of Orthetrum albistylum speciosum increased slightly throughout the experimental period.

Die Liste der bedrohten Tiere und Pflanzen im Emsland ist lang

Kiebitze (Vanellus vanellus) gehören zu den absoluten Verlierern, sagt Jutta Over vom Nabu Emsland/Grafschaft Bentheim. Sie sind im Jahr 2017 im Emsland kaum noch zu sehen und stehen wie fast die Hälfte der 140 Brutvogelarten auf der Liste der gefährdeten Arten. Over hat für unsere Redaktion zum heutigen Tag des Artenschutzes eine Liste bedrohter Tiere und Pflanzen im Emsland erstellt. Von den 140 Brutvogelarten im Emsland seien fast die Hälfte auf der Roten Liste Niedersachsens als gefährdet eingestuft, sieben davon sogar vom Erlöschen bedroht.