Xerothermic Habitats Research Articles

MSV004 Seroprevalence of shigatoxin producing Escherichia coli in breeding sows in Hessen, Germany

Lyme borreliosis is the most prevalent tick-borne disease in Europe. It is caused by spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex and transmitted to humans by ticks of the genus Ixodes. Borrelia afzelii, Borrelia garinii, and Borrelia valaisiana are the most common genospecies in Central Europe. In contrast, Borrelia lusitaniae predominates in Mediterranean countries such as Portugal, Morocco, and Tunisia. In Slovakia, its prevalence is low and restricted to only a few sites.The aim of our research was to study the expansion of ticks into higher altitudes in the ecosystem of the Malá Fatra mountains (north Slovakia) and their infection with B. burgdorferi s.l. pathogens. Questing ticks were collected by flagging in seven years (2004, 2006–2011) at three different altitudes: low (630–660 m above sea level (ASL)), intermediate (720–750 m ASL), and high (1040–1070 m ASL). Tick abundance was highest at the lowest altitude and lowest at the highest altitude. The average infection prevalence of B. burgdorferi s.l. in nymphs and adults was 16.8% and 36.2%, respectively. The number of infected ticks decreased from 38.5% at the lowest altitude to 4.4% at the highest altitude. B. lusitaniae was the most frequently found genospecies (>60% of the ticks found positive for B. burgdorferi s.l.) in all sites in all the studied years with the exception of 2008 when B. afzelii predominated (62%).Our study confirms the spread of Ixodes ricinus ticks to higher altitudes in Slovakia. The discovery that our mountain study sites were a natural foci of B. lusitaniae was unexpected because this genospecies is usually associated with lizards and xerothermic habitats.

Regional and local variation of spider assemblages (Araneae) from coastal grey dunes along the North Sea

AbstractAim This study aims to determine the underlying causes of local and regional patterns of variation in community structure of spiders in coastal grey dunes, and especially whether ecological time constrains the species composition in young and isolated grey dune habitats.Location The study was conducted in coastal dunes from northern France (Boulonnais, Nord‐Pas‐de‐Calais), Belgium (Flemish coastal dunes) and the Netherlands [Amsterdam Water Supply (AWD) dunes and Dunes from the Provincial Water Company North‐Holland].Methods Spiders were collected with pitfall traps in twenty‐eight grey dune patches in the four areas under investigation. Species composition and environmental parameters (vegetation structure, distance to the sea and the patch‐edge, eolic dynamics and lime richness) were determined. Assemblage composition was related to the regional and local environmental factors with the Primer software package to determine the assemblage‐determining parameters. Differences in species presence were analysed as a function of their habitat preference and distribution range.Results Differences in grey dune spider assemblage structure can mainly be attributed to differences in local sand dynamics and the region. Species from dynamic dunes are mainly present in grey dunes from Belgium and France, while species from non‐dunal xerothermic habitats (chalk grasslands and heathland) occur in both the Boulonnais and the north Holland dune region. These species are absent from geologically young or other xerotherm habitat isolated Flemish coastal dunes.Main conclusion The data show that regional variation in spider assemblage composition results from local landscape characteristics (dynamics in the dune area), the latitude and the connectivity to non‐dunal xerothermic habitats. The strong and moderate geological isolation of dune areas from the Flemish coast and the AWD dunes, respectively, results in the absence of (at least some) species that are primarily bound to heathland and/or chalk grassland. This indicates the importance of ecological time for the assemblage structure. The limited dispersal capacity of the heathland and/or chalk grassland species is probably the main reason for their absence.

Syntrichia glabra, a new moss from Germany

Syntrichia glabra J.-P. Frahm & M. T. Gallego is described as new from Germany. It is characterized by small size, dark green colour, distant leaves with a short reflexed hyaline hair-point and transparent upper laminal cells with very low papillae. It has been found three times in xerothermic habitats, such as dry, hot rocks and rocky outcrops in vineyards. The new combination Syntrichia densa (Velen.) J.-P. Frahm is made.

Verbreitung und Wasserhaushalt araukano-patagonischer Proteaceen in Beziehung zu mikroklimatischen Faktoren

To determine ranges of climatic tolerance under which Proteaceae regenerate spontaneously, thermohygrograph records were carried out in the herb layers of numerous habitats. To characterize optimal conditions of the different species, daily average temperature curves were calculated. By means of a statistical analysis, probability of the occurrence of nocturnal freezing in the summer season was determined for typical habitats. To characterize ecologic amplitudes, habitational variation of other values was used: Temperature averages of complete days (general thermic requirements), daily temperature fluctuations (continentality), temperature averages and atmospheric saturation deficit of the warmer half-day (xerothermic adaptation). To characterize water relationships, measurements of relative transpiration were carried out and compared with saturation deficits of the leaves. Results are discussed, relating them with phytogeographic aspects. Furthermore a former investigation is taken into account, related with drought resistance of Patagonic evergreen species. Embothrium coccineum being a “facultative tropophyte”, is distinguished by low thermic requirements. Notwithstanding it also invades habitats presenting rather warm conditions during the light period. The frequency of freezings is high in its typical open biotopes. Distribution on small scale is strongly controlled by the light factor. Embothrium is a typical heliophyte with reference to its rapid transpiration. However, stomatal regulation is slow even under considerable water losses. This feature is equalized by a pronounced plasmatic drought resistance as well as by the ability to shed the leaves. Gevuina avellana is a true evergreen tree like all the following species. Its optimum habitat is characterized by warm conditions, rare nocturnal free zings and reduced thermic fluctuations. By all means the ecological range is relatively wide. Corresponding to its ability for establishing themselve in open habitats of convenient climatic conditions, Gevuina — just as well as the preceding species — is one of the most important pioneers following the forest destruction. The water relationships recall to that of Lomatia hirsuta (see below). This is accordant with the fact, that both trees possess extraordinary thermophilic features, considering the phytogeographic region in question. Optimum habitats of Lomatia dentata are similar to that of Gevuina . However, its ecological ranges are much more reduced with reference to the temperature and humidity factors. On the other hand, this species regenerates and competes very succesfully in shadowy stands. Its typical biotopes are situated in the interior of deciduous Nothofagus forests. Because of that corresponding microclimates are little similar to their regional climate, whic is characterized by moderate continental features. Lomatia ferruginea is the only species restricted to climatic conditions of the temperate rain forests. Correspondingly, the optimum biotope presents low average temperature, small thermic fluctuations and high atmospheric humidity. This species represents a typical example for the drought resistance relations of subantarctic evergreen trees: Stomatal transpiration is suspended when saturation deficit reaches up to 10 % or so. Nevertheless, the subletal deficit lies much higher (76 %). This surprising wide safety range is explained as a compensation for reduced efficacy of the cuticle in permanent humid and windy conditions. Lomatia hirsuta forms a prominent contrast to the preceding species. In relation to continentality, it coincides with Embothriurm , and relative to its thermic requirements is comparable to Gevuina . This tree possesses a special aptitude to occupy xerothermic habitats. Drought resistance is chiefly based on diffusion resistance of the cuticle, and transpiration is very strongly reduced when water losses arrive at a critical value.