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As global biodiversity continues to decline steeply, it is becoming increasingly important to understand diversity patterns at local and regional scales. Changes in land use and climate, nitrogen deposition and invasive species are the most important threats to global biodiversity. Because land use changes tend to benefit a few species but impede many, the expected outcome is generally decreasing population sizes, decreasing species richness at local and regional scales, and increasing similarity of species compositions across sites (biotic homogenization). Homogenization can be also driven by invasive species or effects of soil eutrophication propagating to higher trophic levels. In contrast, in the absence of increasing aridity, climate warming is predicted to generally increase abundances and species richness of poikilotherms at local and regional scales. We tested these predictions with data from one of the few existing monitoring programmes on biodiversity in the world dating to the 1960s, where the abundance of 878 species of macro-moths have been measured daily at seven sites across Hungary. Our analyses revealed a dramatic rate of regional species loss and homogenization of community compositions across sites. Species with restricted distribution range, specialized diet or dry grassland habitat were more likely than others to disappear from the community. In global context, the contrasting effects of climate change and land use changes could explain why the predicted enriching effects from climate warming are not always realized.

KivonatAz észak-amerikai tölgy csipkéspoloskát (Corythucha arcuata) Európában először Észak-Olaszországban észlelték (2000). Magyarországon 2013-ban találták meg, az azóta eltelt öt évben, különösen pedig 2016-ban és 2017-ben gyors terjeszkedést mutatott. 2017 őszéig öt kivételével (Borsod-Abaúj-Zemplén, Nógrád; Győr-Moson-Sopron, Vas és Veszprém) minden magyarországi megyében előkerült. Békés, Csongrád, Jász-Nagykun-Szolnok és Baranya megyei kocsányos tölgyesek-ben már állományszintű, tömeges fellépését is észleltük, aminek összesített területe a becslések szerint legalább 5000 ha. A következő években további terjedése és tömegszaporodásai várhatóak. A kártevő tömeges fellépése július elejére/kö-zepére jelentős lombsárgulást okoz. Ennek hosszú távú hatásai a tölgyesek növedékére, egészségi állapotára, makktermésére egyelőre nem ismertek. Jelenleg megfelelő védekezési mód sem ismert.Kulcsszavak: inváziós faj, tölgy csipkéspoloska, Corythucha arcuata, terjeszkedés, Quercus. RAPID AREA EXPANSION AND MASS OCCURRENCES OF THE INVASIVE OAK LACE BUG [CORYTHUCHA ARCUATA (SAY 1932)] IN HUNGARY AbstractThe North American oak lace bug (Corythucha arcuata) was first discovered in Europe in Northern Italy (2000). In 2013, it was found in Hungary. In the last five years, particularly in 2016 and 2017, the species showed rapid area expansion. Until autumn 2017 it has been found in all Hungarian counties except five ones (Borsod-Abaúj-Zemplén, Nógrád; Győr-MosonSopron, Vas and Veszprém). Outbreaks were recorded in several pedunculate oak stands in Békés, Csongrád, Jász-Nagykun-Szolnok and Baranya counties, covering ca. 5,000 hectares of forest area in total. Further spread and outbreaks are expected in the next years. The severe infestation causes mass yellowing of the foliage by early and mid-July, long term consequences of this effect are not yet known. Neither efficient nor environmentally friendly control methods were established by now.