The effect of grazing on biodiversity in coastal dune heathlands

The effect of sheep grazing on species richness, higher order diversity measures, inequality, species composition, functional diversity and allometric relationships at a coastal dune heathland site was investigated. After a prescribed fire in 2002, the site was divided into two parts, where one of the parts was unmanaged and the other part was fenced and grazed by sheep. Sheep grazing had a positive effect on species richness as well as a significant positive effect on the functional diversity at the coastal dune heathland site. Generally, the cover of dwarf shrubs was negatively affected by grazing, whereas the cover of sedges and grasses was positively affected by grazing. There is a need for comparative investigations of the effect of different management methods not only on floristic biodiversity, but on all relevant kinds of biodiversity as well as on soil structure, soil chemistry and habitat micro- and macrostructure. Consequently, we advocate the initiation of an international systematic investigation of the effect of different management methods.     

Balancing fuelwood and biodiversity concerns in rural Nepal

An agent-based model is developed to explore the pattern of fuelwood collection in an 1178 ha forest area in rural mountainous Nepal. The model relates fuelwood collection intensity and amount of dead wood available for collection to the diversity of polypore species, a group of strictly dead wood dependent fungi which can be used as indicators of the biodiversity associated with dead wood. By analysing scenarios of increased collection the model shows that the relative impact on polypore diversity is rising more rapidly than the time used for collection. This indicates that better market access in the future could potentially imply a major threat to biodiversity associated with dead wood.     

Relationships between reproductive performance and organochlorine contaminants in great black-backed gulls (Larus marinus)

The great black-backed gull Larus marinus is a top predator in subarctic and temperate marine ecosystems, and the aim of this study was to investigate if organochlorines (OCs) were related to reproductive performance in this species at the subarctic parts of the Norwegian Coast. We measured blood levels of various OCs in 53 breeding birds. The OC levels were relatively low compared to levels found in nearby arctic areas. In females, however, there was a significant positive relationship between blood concentrations of OCs, especially hexachlorobenzene (HCB) and, p,p'-dichlorodiphenyldichloroethylene (DDE), and egg laying date, and a positive relationship between the probability of nest predation and blood concentration of beta-hexachlorocyclohexane (beta-HCH), oxychlordane, and DDE. In females with high levels of OCs, especially persistent polychlorinated biphenyls (PCBs), there was also a decline in egg volume as egg laying progressed; i.e. the second and third laid egg were relatively smaller, compared to females with low OC levels. No relationships between reproductive parameters and OC levels were found in males.     

Human impact on the landscape of small islands in the West-Estonian archipelago

Research on the development of the interrelationships between society and environment is crucial for the understanding of contemporary landscapes. The West-Estonian archipelago provides an opportunity for such investigations because of its small size, landscape diversity, and well-defined economic activities. The contemporary landscapes of the islands reflect environmental changes resulting from centuries of human activity. This paper describes both natural and human factors in the change in landscape of small Estonian islands during the last centuries. During the period 1850–1940, human activity diversified the landscape structure. During World War II, with the establishment of Soviet rule, the islets were depopulated; their landscape became more uniform and lost their economic and ecological vitality. The re-establishment of private ownership of land and a market economy is predicted to result in positive changes in the landscape of the islets.     

Oil exposure in a warmer Arctic: potential impacts on key zooplankton species

Oil exploration activities are rapidly increasing in Arctic marine areas with potentially higher risks of oil spills to the environment. Water temperatures in Arctic marine areas are simultaneously increasing as a result of global warming. Potential effects of a combination of increased water temperature and exposure to the PAH pyrene were investigated on fecal pellet and, egg production and hatching success of two copepod species, Calanus finmarchicus and Calanus glacialis, sampled in Disko Bay, Greenland on 23–25 April 2008. The two species were exposed daily to nominal pyrene concentrations of 0-0.01-0.1-1-10-100 nM at water temperatures of 0.5, 5 and 8°C for 9 and 7 days, respectively. Daily measurements of faecal pellet production, egg production and hatching showed different responses of the two species to the applied stressors. When temperature increased, low concentrations of pyrene caused a decrease in faecal pellet production by C. finmarchicus, whereas C. glacialis faecal pellet production showed no negative response to pyrene exposure when temperatures increased. Pyrene exposure decreased egg production of C. finmarchicus at all temperatures, but the species was more sensitive at 0.5 and 8°C. A lag period of 1 day before egg production began was prolonged with several days when warmer water was combined with pyrene exposure. Egg production by C. glacialis was only negatively affected by pyrene in a dose-dependent manner at 0.5°C. Hatching success in both species was not affected by pyrene, where increased water temperatures led to a higher hatching success. In conclusion, C. glacialis seemed to be the less sensitive of the two species to the stress combination of increased water temperature and pyrene exposure. As a consequence of the differential responses of the two species, their competition can be impaired with a consequent impact on energy transfer between trophic levels.     

Private–public partnership: An exceptional solution in nature conservation in Norway

Abstract

In Norway, traditional nature conservation by government declaration is still the dominant way of protecting nature areas of national and international interest. This article presents some results from a case study of one exceptional case of private–public partnership in nature conservation. Strong opposition among local actors resulted in conservation by legal contracts between public and private actors. Discussing some possible explanations, the authors argue that a rather special network among the local community and central government and a rather creative combination of environmental and agricultural policy instruments were essential for this particular outcome.     

Effects of increased sea water concentrations of CO2 on growth of the bivalve Mytilus edulis L

It has been proposed that emission of anthropogenic carbon dioxide to the atmosphere will lead to increased concentrations of CO(2) in sea water corresponding to a decrease of pH of several tenths of pH units. An experiment was performed to test the effects of increased sea water concentrations of CO(2) on shell growth of the blue mussel Mytilus edulis. The experiment was performed in aquaria continuously flushed with sea water spiked with CO(2) to provide five different levels of pH between 6.7 and control sea water with a pH of 8.1. The shell length of the mussels was measured at the start and end of the 44 days experimental period. No mortality was observed during the first 23 days of the experiment. The growth increment in mm was much larger for small mussels than for large mussels, but relative growth profile as function of pH was more similar in the two size groups; observed differences may be random variation between samples. The experiments showed that CO(2) induced reduction of pH affects the growth of M. edulis negatively. There was a strong and statistically significant decrease in growth at the lowest pH values, with virtually no growth at pH = 6.7 and reduced growth at pH = 7.1. The effect seems to set in between pH 7.4 and 7.1; at mean pH levels 7.4 and 7.6 the growth increments were not significantly different from growth at normal pH 8.1.     

Predicting low biota to sediment accumulation factors of PAHs by using infinite-sink and equilibrium extraction methods as well as BC-inclusive modeling

Sequestration of polycyclic aromatic hydrocarbons (PAHs) results in the slow release of PAHs from sediment to the aqueous environment, thus limiting bioavailability. Three methods to account for the limited bioavailability of native PAHs to the gastropod Hinia reticulata were therefore investigated: (i) infinite-sink extractions that measure desorption; (ii) equilibrium extractions that measure freely dissolved pore water concentrations and (iii) black carbon-inclusive modeling. The rapidly desorbing fraction was estimated based on the amount desorbed by Tenax. Relatively small amounts of PAHs (<9%) were present in F(rapid) and the observed solid-water distribution ratios (K(d,obs)) were approximately 1-2 orders of magnitude higher than literature K(oc) values. Biota to sediment accumulation factors (BSAFs) measured in the gastropod H. reticulata ranged from 0.02 to 0.07, 10-140 times lower than the theoretical value of approximately 1-2. The BSAFs calculated using the rapidly desorbing fraction or freely dissolved aqueous concentrations were also much lower than the theoretical value, and median values differed from the measured BSAFs by only a factor of 1.5-9. Furthermore, the result of using a BC-inclusive BSAF model could explain the deviation from the theoretical BSAF value and account for the low bioavailability of these native PAHs to H. reticulata. Risk assessment strategies of in situ contamination should therefore include a combination of chemical methods accounting for bioavailability, as well as bioaccumulation studies.