Does snail grazing affect growth of the old forest lichen Lobaria pulmonaria?

Grazing marks from snails are frequently observed in populations of the old forest epiphyte Lobaria pulmonaria. However, grazing marks are more numerous in thalli from deciduous broadleaved forests than in thalli from boreal Picea abies forests, due to higher populations of lichen-feeding molluscs in deciduous stands. Here we tested for deleterious effects of snails on the lichens by transplanting 600 more or less grazed L. pulmonaria thalli from deciduous forests to snail-free P. abies forests. Subsequent measurements showed that growth rates were as high in thalli with many grazing marks as those without, suggesting that growth of mature lobes of L. pulmonaria are not inhibited by the recorded grazing pressure imposed by lichen feeding snails

Differences in soil arthropod communities along a high altitude gradient at Shergyla Mountain, Tibet, China

This is the first time that the soil arthropod communitycomposition along a high-altitude gradient (3,837, 4,105, and5,050 m a.s.l.) has been investigated in eastern Tibet, China.Five soil samples of 50 cm super(2) were taken from each site andextracted for 7 days in Berlese/Tullgren funnels without heating.Acari was the dominant group of arthropods at all three elevations(79%, 53%, and 54%, respectively, from the lower site to the uppersite). Prostigmata and Oribatida were more abundant thanMesostigmata and Astigmata at all three elevations. Mesostigmataand Oribatida were most abundant at the upper elevation (about8,300 and 29,000 individuals/m super(2), respectively).Prostigmata and Astigmata were most abundant at the lowerelevation (about 170,000 and 20,000 individuals/m super(2),respectively). Collembola was most abundant at the middleelevation (about 68,000 individuals/m super(2)). The insect taxawere most abundant at the lower elevation. Diptera larvae,Protura, and Homoptera were the most abundant taxa along theelevation gradient, while Hemiptera, Thysanoptera, and Proturaoccurred only at the lower elevation. A multivariate redundancyanalysis (RDA) shows that 64% of the variance can be explained byaltitude. A change in dominant mite taxa along the elevationgradient could be seen. From the lower to upper sites, thedominant taxa changed from Prostigmata to Prostigmata andOribatida, and then to Oribatida. About 33 genera in 24 familiesof oribatid mites were found. The numbers of genera from thelower, middle, and upper elevation were 14, 20, and 19,respectively

Lichen specificity of Oribatid mites (Acari; Oribatida) on limestone walls in the Great Alvar of Öland, Sweden.

Författarna har undersökt kvalster, hoppstjärtar och andra ryggradslösa djur på lavar som växer på stenmurar på Ölands alvar. Åtta olika kvalsterarter hittades. Generellt sett var vissa typer av lavar betydligt artrikare än andra. De rikaste är de som har strukturer som de små djuren kan gömma sig i

Overwintering of terrestrial Arctic arthropods: the fauna of Svalbard now and in the future

There are over 500 species of arthropods recorded from Svalbard. These animals overwinter either within the soil or on the ground surface, and have to tolerate an environment where the ground is frozen for over 9 months each year. Three cold-tolerance strategies have been described from Svalbard invertebrates: freeze avoidance, freeze tolerance and desiccation. Once in a coldtolerant state the animals can be extremely cold tolerant in terms of both minimum exposure temperature and period of exposure. How the overwintering capabilities of these animals will be affected by climate changes during the next 100 years, as predicted by climate models, is not yet known. Four principle factors with an impact on overwintering of the terrestrial arthropod fauna are outlined here: (1) warmer winter temperatures, with an increased frequency of extreme events such as freeze–thaw cycles and surface icing; (2) changes in snow fall and snow lie; (3) pollutant load; and (4) dispersal of invertebrates to Svalbard. Finally, areas where further research is required are highlighted: including the development of controlled multi-season field experiments; effect of freeze–thaw cycles; changes in thickness and distribution of snow lie, with the subsequent effects on duration of the summer period; chill susceptibility of soil arthropods; assessing potential colonizing species and the likelihood of these species becoming established; assessing the effect of gene flow from surrounding populations; interactions between pollution and cold tolerance; anoxia stress; and the genetics of cold tolerance

Predation by beetles (Carabidae, Staphylinidae) on eggs and juveniles of the Iberian slug Arion lusitanicus in the laboratory

Arion lusitanicus has become a major pest species in western Norway in the last few years. This species originates from southern Europe but has been spread by humans over large parts of central and northern Europe during recent decades. Slugs have traditionally been controlled by the use of molluscicides; but, as these may have serious ecological side effects, biological control of slugs is highly desirable. Potential biological control agents include nematodes, gastropods and arthropods. In laboratory experiments, we tested whether five common predator beetles would feed on eggs and juveniles of A. lusitanicus. The species Carabus nemoralis, Nebria brevicollis, Pterostichus melanarius and Pterostichus niger (Carabidae) as well as Staphylinus erythropterus (Staphylinidae) were tested, of which only P. melanarius has been tested on A. lusitanicus previously. Nebria brevicollis did not feed on slug eggs or newly hatched slugs, but the remaining four species all killed and ate a large proportion of the eggs and hatchlings offered. Both P. melanarius and P. niger also destroyed A. lusitanicus eggs and hatchlings under conditions emulating those in the field. Prey size choice experiments were conducted by feeding C. nemoralis, P. niger and S. erythropterus on different sizes of A. lusitanicus. Carabus nemoralis was also given a choice between two slug species, A. lusitanicus and Deroceras reticulatum. A significant preference for slugs smaller than one gram was evident for C. nemoralis, while the other beetles struggled much more to overcome the mucus of juvenile slugs. No significant preference was found between A. lusitanicus and D. reticulatum as prey for C. nemoralis. We also discuss the feasibility of biological control of A. lusitanicus using beetle predators

Distribution and spread of the invasive slug Arion vulgaris Moquin-Tandon in Norway

The present distribution of the invasive slug Arion vulgaris Moquin-Tandon was studied in Norway. This important pest species has spread to many parts of Europe during the last decades, inflicting damage to agriculture and domestic gardens. It was first recorded in Norway in 1988, and has since spread to many parts of the country and is now recorded in 192 municipalities. We surveyed the current distribution by sampling and gathering species records in cooperation with garden societies and local authorities. Based on these records, we present distributional data as well as relative predictions of future distributions based on geoclimatic parameters. Currently, A. vulgaris covers most of coastal southern Norway while it shows a patchy distribution in northern Norway, recorded as far north as Finnsnes in Troms County

The terrestrial invertebrate fauna of Edgeøya, Svalbard: Arctic landscape community composition reflects biogeography patterns

Colonisation and immigration history is often neglected as a factor when investigating community or species distribution patterns. However, for dynamic systems that are still reacting to large-scale environmental change, such as the retreat of the ice since the last glacial maximum, colonisation history may explain a large amount of the variation between geographically distinct communities. The High Arctic archipelago of Svalbard presents an opportunity to test whether it is possible to observe the effects of large-scale biogeographical patterns on species distribution at landscape scales. Svalbard has one of the best described inventories of the invertebrate fauna in the Arctic. Nonetheless, the majority of the species records originate from the more accessible west coast and the invertebrate fauna of the whole eastern region, including Edgeøya, is virtually unknown. Edgeøya is located at the eastern fringe of the archipelago on the boundary between Palaearctic and Nearctic faunas. It was expected that post-colonisation dispersal within Edgeøya would conceal routes to the archipelago. Samples were obtained from six locations along the coast of Edgeøya between 2009 and 2010. 140 invertebrate species were identified belonging to 69 different genera of which 16 are new records for Svalbard. Most new species present an eastern Palaearctic distribution. Habitat variables (percentage cover of moss, lichen, vascular plant, or bare soil) fail to explain 35.5% of the differences among sites. However, cluster analysis reveals a clear east–west distribution pattern across the island suggesting that pan-Arctic dispersal routes can be identified even at relatively short geographical scales