Search results for "Tora"
showing 10 items of 3070 documents
Effects of Natura 2000 on nontarget bird and butterfly species based on citizen science data
2020
The European Union's Natura 2000 (N2000) is among the largest international networks of protected areas. One of its aims is to secure the status of a predetermined set of (targeted) bird and butterfly species. However, nontarget species may also benefit from N2000. We evaluated how the terrestrial component of this network affects the abundance of nontargeted, more common bird and butterfly species based on data from long-term volunteer-based monitoring programs in 9602 sites for birds and 2001 sites for butterflies. In almost half of the 155 bird species assessed, and particularly among woodland specialists, abundance increased (slope estimates ranged from 0.101 [SD 0.042] to 3.51 [SD 1.30…
Spatial and temporal variation of community composition and species cover following dune restoration in the Devesa de Albufera (Valencia, Spain).
2015
Plant populations were reintroduced to the coastal dune bar of the Devesa de Albufera from 1988 to 2004; different coastline sections received different species composition and cover. With the aim to detect spatial and temporal variation of floristic diversity, we compared current species composition and cover across the length of the Devesa and across the dune bar with those imposed at the time of restoration. Non-metric multidimensional scaling (NMDS) detected significant differences both across the dune faces and across the coast sections. Differences across the dune faces reflect the sea-inland ecological gradient and resulted from a spatial rearrangement of plant populations: Calystegi…
How to Assess the Ecological Status of Highly Humic Lakes? Development of a New Method Based on Benthic Invertebrates
2021
Highly humic lakes are typical for the boreal zone. These unique ecosystems are characterised as relatively undisturbed habitats with brown water, high acidity, low nutrient content and lack of macrophytes. Current lake assessment methods are not appropriate for ecological assessment of highly humic lakes because of their unique properties and differing human pressures acting on these ecosystems. This study proposes a new approach suitable for the ecological status assessment of highly humic lakes impacted by hydrological modifications. Altogether, 52 macroinvertebrate samples from 15 raised bog lakes were used to develop the method. The studied lakes are located in the raised bogs at the c…
Epiphytic bacteria make an important contribution to heterotrophic bacterial production in a humic boreal lake
2017
Bacterial production (BP) in lakes has generally only been measured in the pelagic zone without accounting for littoral BP, and studies of BP at the whole-lake scale are very scarce. In the dystrophic humic lakes, which are common throughout the boreal region, low light penetration through water has been assumed to seriously limit available habitats for littoral organisms. However, many highly humic boreal lakes have extensive partly submerged vegetation around the lake perimeter which can provide well-lit substrata for highly productive epiphyton. We measured epiphytic BP on the littoral vegetation and pelagic BP in a small highly humic boreal lake in Finland during an open-water season an…
Lake restoration influences nutritional quality of algae and consequently Daphnia biomass
2020
AbstractFood quality is one of the key factors influencing zooplankton population dynamics. Eutrophication drives phytoplankton communities toward the dominance of cyanobacteria, which means a decrease in the availability of sterols and long-chain polyunsaturated fatty acids (EPA and DHA). The effects of different restoration measures on the nutritional quality of the phytoplankton community and subsequent impacts on zooplankton biomass have rarely been considered. We analyzed the nutritional quality of phytoplankton in the eutrophic Lake Vesijärvi in southern Finland over a 37-year period, and studied the impacts of two restoration measures, biomanipulation and hypolimnetic aeration, on th…
Lake browning impacts community structure and essential fatty acid content of littoral invertebrates in boreal lakes
2021
AbstractMany lakes in the northern hemisphere are browning due to increasing concentrations of terrestrial dissolved organic carbon (DOC). The consequences of lake browning to littoral invertebrates, however, are not fully understood. We analyzed community structure and fatty acid (FA) profiles of littoral invertebrates in humic (DOC-rich) and clear-water lakes in Eastern Finland. We found higher abundance of chironomids (Diptera: Chironomidae) in humic compared to clear-water lakes, whereas stoneflies (Plecoptera) and mayflies (Ephemeroptera: Baetidae) were more abundant in clear-water lakes. Taxon explained 65% of the differences in the FA composition of littoral invertebrates. However, t…
Experimental size-selective harvesting affects behavioral types of a social fish
2019
In most fisheries, larger fish experience substantially higher mortality than smaller fish. Body length, life history, and behavioral traits are often correlated, such that fisheries-induced changes in size or life history can also alter behavioral traits. However, empirical evidence regarding how size-selective harvesting alters the evolution of behavioral traits in exploited stocks is scarce. We used experimental lines of Zebrafish Danio rerio that were exposed to positively size-selective, negatively size-selective, or random harvest over five generations. Our aim was to investigate whether simulated fishing changed the mean personality of the surviving females five generations after ini…
Dispersion of vendace eggs and larvae around potential nursery areas reveals their reproductive strategy
2019
Depending on their reproductive strategy, different fish species aim to aggregate or disperse eggs and larvae in their reproductive habitat. Many pelagic species disperse their eggs widely around the potential nursery areas. Larval dispersion or aggregation affects population sub‐structuring, which has important implications in fisheries management and conservation of the natural spatial diversity in populations. The dispersion of larval vendace (Coregonus albula) was quantified in two oligotrophic Finnish lakes, and effects of density and environmental variables on the inter‐annual variation in the larval distribution were examined by analysing spatial abundance data from the lakes from 19…
Effects of Modified Atmosphere Packaging and Chitosan Treatment on Quality and Sensorial Parameters of Minimally Processed cv. ‘Italia’ Table Grapes
2021
Table grape is a non-climacteric fruit, very sensitive to water loss and gray mold during postharvest handling and storage. The aim of this work was to evaluate the effects of modified atmosphere packaging and chitosan treatment on quality and sensorial parameters of minimally processed cv. ‘Italia’ table grape during cold storage (14 days at 5 °C) and shelf-life (7 and 14 days of cold storage plus 5 days at 20 °C), reproducing a retail sales condition. Our data showed a significant effect of high CO2-modified atmosphere in combination with chitosan and alone on preserving quality, sensorial parameters, and delaying decay of minimally processed table grape. The most effective treatment in t…
Nutritional quality of littoral macroinvertebrates and pelagic zooplankton in subarctic lakes
2021
Littoral benthic primary production is considered the most important energy source of consumers in subarctic lakes. We analyzed essential fatty acid (EFA) and amino acid (EAA) content of 23 littoral benthic macroinvertebrate taxa as well as cladocerans and copepods from pelagic and littoral habitats of 8–9 subarctic lakes to compare their nutritional quality. Pelagic crustacean zooplankton had significantly higher EFA and total FA content (on average 2.6‐fold and 1.6‐fold, respectively) than littoral macroinvertebrates in all our study lakes. Specifically, docosahexaenoic acid (DHA), one of the most important EFA for juvenile fish, was almost exclusively found in pelagic copepods. In littor…