A Leymus arenarius előfordulása a Kiskunságban

Egy idegenhonos, évelő fűfaj, a buckalakó partirozs (Leymus arenarius (L.) Hochst.) hat kivadult állományát találtuk a Kiskunságban. A fajnak a Nagyalföldről eddig még nem volt adata. A leg­több előfordulás több száz négyzetméter kiterjedésű, néhány esetben a faj szinte monodomináns állo­mányt alkot, és az egyik állomány már egy nyílt homokpusztagyepben is megjelent. Feltételezésünk sze­rint ez a faj a Duna–Tisza közi homokhátságon akár inváziós fajjá is válhat.

Variation in Growth Response of Coastal Dune-Building Grass Species Ammophila Arenaria and Leymus Arenarius to Sand Burial

Ammophila arenaria and Leymus arenarius are dune-building grass species native to European seacoasts. The present study aimed to compare growth responses to the sand burial of A. arenaria and L. arenarius from coastal habitats of the Baltic Sea, when the intensity of sand accretion was relatively low under controlled conditions. Plants were grown from seeds collected from natural coastal habitats, transplanted into individual containers, buried in the sand at different depths in the rapid shoot elongation stage, and further cultivated (11 or 9 weeks) in an automated greenhouse. Burial in sand significantly stimulated the growth of shoots of A. arenaria, the effect was earlier at high burial intensities (46 and 60%) and was evident ten days after the start of treatment. Both shoot and root dry mass increased for plants buried at 13%; however, increased burial depth (37, 46 and 60%) resulted in a significant increase in root biomass. In comparison, shoot biomass decreased significantly at the highest burial intensity (60%). For L. arenarius, there was no direct dependence of shoot elongation rate on burial depth. There was a tendency for increased elongation growth and biomass allocation to leaf sheaths despite a decrease in total shoot mass. Most strikingly, root biomass decreased with sand burial in parallel with increased burial depth up to 21% intensity. In conclusion, although both grass species showed a positive shoot growth response to moderate sand burial intensity, differences in individual responses at the morphological and physiological level indicate the existence of different genetically based adaptation strategies.

Promising plant species for reducing bird populations at airfields

For crops and landings on the territory of airfields in order to reduce the population of birds, promising: Limus (Leymus arenarius), gray's Sedge (Carex grayi), Melica (Melica altissima), bison sweet (Hierochloe odorata), Japanese Spiraea (Spiraea japonica) and species of dogwood (Cotoneaster sp.).

Ecosystem CO2 flux rates in relation to vegetation type and age of Leymus arenarius dunes on Surtsey

The primary succession on the 50 year old volcanic island of Surtsey, Iceland, has been intensively studied. Initial soil development and other belowground processes are important drivers of primary succession but frequently overseen. A Leymus arenarius and Honckenya peploides dominated plant community has formed a relatively stable successional sere on the island, where external inputs of nutrients remain low. These plants have had a stable <10% aboveground surface cover during the past 20 years, but less is known about their belowground development. We investigated the organic matter (carbon) output and input processes (soil respiration, ecosystem respiration and photosynthesis) of the community and how they were affected by soil temperature, soil water content, vegetation and age of L. arenarius dunes. We found that both soil respiration and root stocks have increased substantially from 1987, when an earlier study was conducted. The same pattern was found when different aged L. arenarius dunes were studied. L. arenarius had a stronger effect on the soil respiration fluxes than its surface cover might indicate, through its much higher photosynthesis rates than H. peploides. The study furthermore illustrated how water stress may temporally limit belowground processes in this coastal community.

Accumulation of nitrogen and organic matter during primary succession of <i>Leymus arenarius</i> dunes on the volcanic island Surtsey, Iceland

Initial soil development and enhanced nutrient retention are often important underlying environmental factors during primary succession. We quantified the accumulation rates of nitrogen (N) and soil organic matter (SOM) in a 37-year-long chronosequence of Leymus arenarius dunes on the pristine volcanic island Surtsey in order to illuminate the spatiotemporal patterns in their build-up. The Leymus dune area, volume and height grew exponentially over time. Aboveground plant biomass, cover or number of shoots per unit area did not change significantly with time, but root biomass accumulated with time, giving a root / shoot ratio of 19. The dunes accumulated on average 6.6 kg N ha−1 year−1, which was 3.5 times more than is received annually by atmospheric deposition. The extensive root system of Leymus seems to effectively retain and accumulate a large part of the annual N deposition, not only deposition directly on the dunes but also from the adjacent unvegetated areas. SOM per unit area increased exponentially with dune age, but the accumulation of roots, aboveground biomass and SOM was more strongly linked to soil N than time: a 1 g m−2 increase in soil N led on average to a 6 kg C m−2 increase in biomass and SOM. The Leymus dunes, where most of the N has been accumulated, will therefore probably act as hot spots for further primary succession of flora and fauna on the tephra sands of Surtsey.

Anthostomella arenaria. [Descriptions of Fungi and Bacteria].

A description is provided for Anthostomella arenaria. Some information on its dispersal and transmission and conservation status is given, along with details of its geographical distribution (Europe (Belgium, Denmark, Finland, Norway, Sweden and UK)) and habitats. This species has been recorded from coastal dunes and grasslands. Some members of Anthostomella are endobionts for part of their life cycle, but for the present species the time of substratum colonization and nutritional relations with the associated plant (Leymus arenarius) have not been established.

Accumulation of nitrogen and organic matter during primary succession of <i>Leymus arenarius</i> dunes on the volcanic island Surtsey, Iceland

The volcanic island of Surtsey has been a natural laboratory where the primary succession of flora and fauna has been monitored, since it emerged from the N-Atlantic Ocean in 1963. We quantified the accumulation rates of nitrogen (N) and soil organic matter (SOM) in a 37 year long chronosequence of Leymus arenarius dunes in order to illuminate the spatiotemporal patterns in their build-up in primary succession. The Leymus dune area, volume and height grew exponentially over time. Aboveground plant biomass, cover or number of shoots per unit area did not change significantly with time, but root biomass accumulated with time, giving a root-shoot ratio of 19. The dunes accumulated on average 6.6 kg N ha−1 year−1, which was 3.5 times more than is received annually by atmospheric deposition. The extensive root system of Leymus seems to effectively retain and accumulate large part of the annual N deposition, not only deposition directly on the dunes but also from the adjacent unvegetated areas. SOM per unit area increased exponentially with dune age, but the accumulation of roots, aboveground biomass and SOM was more strongly linked to soil N than time: 1 g m−2 increase in soil N led on the average to 6 kg C m−2 increase in biomass and SOM. The Leymus dunes, where most of the N has been accumulated, will therefore probably act as hot-spots for further primary succession of flora and fauna on the tephra sands of Surtsey.