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Dutch elm Disease and the Habitat of Endangered Rosalia Longicorn Rosalia alpina (L.): A Conservation Paradox?

Bartnik C., Michalcewicz J., Ciach M.

Polish Journal of Ecology

2015

Vol. 63, nr 3

440--447

In central Europe, the endangered Rosalia longicorn Rosalia alpina (L.) has rarely been observed to develop in the wood of elms Ulmus sp.; however, this beetle has recently expanded into habitats formed by elms. The factors driving these changes are unknown in detail, but a potential one is the increasing amount of breeding material, namely, dead elm wood. Dutch elm disease, caused by the fungi Ophiostoma ulmi and O. novo-ulmi, by killing off elm trees, has created a supply of dead wood. The aim of this work was to assess the potential role of Dutch elm disease in the formation of habitats suitable for the endangered Rosalia longicorn. The health of four elm stands (Carpathians, SE Poland) was analysed and the pathogen responsible for elm death were determined by DNA sequence comparison. O. novo-ulmi — the causative agent of Dutch elm disease — was isolated from weakened and dying trees at all studied localities. In total, 30% of the elm trees were dead, 34% showed signs of dieback or were moribund, while some 36% showed no signs of dieback (N = 120). The presence of the Rosalia longicorn was recorded at all four studied localities. The use of elms as a host plant was long-term; dead trees served as a breeding material through the past 11 years. Our results indicate that O. novo-ulmi is playing an important part in the death of elms in Rosalia longicorn localities. Dutch elm disease, due to its wide distribution, may shape suitable habitats for Rosalia longicorn within the species' range. While the chronic nature of the disease contributes to the slow and inexorable death of these trees, it may at the same time be a factor promoting the long-term stability of Rosalia longicorn habitats.

12 millennia of climatic and human induced vegetation changes in the lower san valley near Jarosław (se poland) in the light of Pollen analysis

Kołaczek P.

Studia Quaternaria

2011

Vol. 28

25-39

Vegetation changes in the Lower San Valley near Jarosław are reconstructed from the Younger Dryas to the present time on the basis of palynological analysis of the peat core. The pollen profile came from a an old riverbed and was supplemented by radiocarbon datings. The Younger Dryas and early Preboreal vegetation was characterised by a high proportion of forest communities with pine (Pinus sylvestris and P. cembra) and birch (Betula), while patches of open area were dominated by the steppe with Artemisia. Climatic amelioration during the Preboreal chronozone led to the rapid spread of elm (Ulmus), which was probably a dominant taxon on the lowest terraces of the valley. Terrestrialization of the water body existing in the palaeomeaner and the subsequent beginning of peat accumulation caused a deterioration in pollen preservation. Hence, the interpretation of the profile section spanning the period between the Boreal and Subatlantic chronozones was seriously disturbed due to selective corrosion and the overrepresentation of Pinus sylvestris type and Filicales monolete sporomorphs. Between ca. 336 and 1152 AD fluctuations in woodland cover were recorded. Important components in those forests, despite the domination of Pinus sylvestris, were Quercus, Carpinus betulus, Fagus sylvatica and Abies alba. The first pollen grains of cereals (Cerealia type) were found before ca. 1605-1414 BC and may be attributed to the agricultural activity of the Neolithic and/or early Bronze tribes. Periods of strong deforestation caused by humans were probably related to the time when the Tarnobrzeska Group of the Lusatian Culture and the Przeworska Culture were active. The first groups of Slavs did not significantly influence the environment, but the subsequent development of those groups led to more visible deforestation, which was triggered after the establishment of Jarosław in the 11th century AD.