<p>According to the exploitation ecosystem hypothesis (EEH), terrestrial ecosystems are characterized by well defined trophic levels and strong trophic interactions with community level tropic cascades. In unproductive terrestrial habitats as tundra heaths, the energy shunt from litter and apparent competition between herbivores and detritivores are expected to be important for the structure and dynamics of the invertebrate community. The aim of this study was to test this hypothesis by investigating if plant litter accumulation was affecting the invertebrate community on a nutrient-poor tundra heath. The study was performed during one summer on the highland part of Joatka research area, in the north of Norway.</p><p>The experimental area included 16 plots (100 m² each), of which 12 had been littermanipulated. On four plots the amount of litter was increased by 100 %, on four by 200 % and on four by 400 %. Four plots were untreated and used as control plots. Invertebrates were collected by emergence traps (which cover an area of 1 m²), one trap on each plot and one pitfall trap inside each emergence trap. During the study period, traps were emptied and moved twice, resulting in three sampling periods. The invertebrates collected were counted and their length was measured, than all invertebrates were sorted into taxa and trophic guilds. During the study period, herbivore grazing damage was investigated on all 16 experimental plots, signs of herbivores on leaves of vascular plants in an area covering 3 m2 per plot were noted, for every leaf with signs of herbivory the percentage of leaf area removed was estimated.</p><p>Plant biomass and plant species composition were estimated in all experimental plots by harvesting above-ground plant parts. In each plot, two squares were randomly chosen and all biomass in this square was collected. Plant biomass was sorted in to following groups: dwarf birch, billberry, Salix herbacea, Salix spp, graminoids, herbs, lichens, mosses and dwarf shrub. Before weighing the plant material, it was stored in paper bags at room temperature and then dried for 48 h at 40°C. In order to detect fertilisation effects, all bilberry shoots that had been produced during the actual summer were separately weighted when analyzing the plant biomass.</p><p>The result showed that the invertebrate community in this area is dominated by carnivores while detritivores, parasitoids and herbivores are quite rare, this was in accordance with previous studies made in the area. Litter manipulation did not create any significant variation in the community structure, but there was a slight tendency that carnivore biomass increased and biomass of herbivores decreased when litter was added to the system. In contrary to this,</p><p>gracing activity especially on dwarf willow (Salix herbacea) increased in plots were 100 % and 200 % more litter was added. There is a positive correlation between biomass of herbivores and detritivores but the reason for this seems unclear. No fertilisation effect was detected in litter manipulated plots. The structure and dynamics of the actual community could not be described by the food web theory EEH and energy shunt from litter and apparent competition between herbivores and detritivores. It seems to be several complicating factors to take into consideration when describing this community.</p>

According to the exploitation ecosystem hypothesis (EEH), terrestrial ecosystems are characterized by well defined trophic levels and strong trophic interactions with community level tropic cascades. In unproductive terrestrial habitats as tundra heaths, the energy shunt from litter and apparent competition between herbivores and detritivores are expected to be important for the structure and dynamics of the invertebrate community. The aim of this study was to test this hypothesis by investigating if plant litter accumulation was affecting the invertebrate community on a nutrient-poor tundra heath. The study was performed during one summer on the highland part of Joatka research area, in the north of Norway. The experimental area included 16 plots (100 m2 each), of which 12 had been littermanipulated. On four plots the amount of litter was increased by 100 %, on four by 200 % and on four by 400 %. Four plots were untreated and used as control plots. Invertebrates were collected by emergence traps (which cover an area of 1 m2), one trap on each plot and one pitfall trap inside each emergence trap. During the study period, traps were emptied and moved twice, resulting in three sampling periods. The invertebrates collected were counted and their length was measured, than all invertebrates were sorted into taxa and trophic guilds. During the study period, herbivore grazing damage was investigated on all 16 experimental plots, signs of herbivores on leaves of vascular plants in an area covering 3 m2 per plot were noted, for every leaf with signs of herbivory the percentage of leaf area removed was estimated. Plant biomass and plant species composition were estimated in all experimental plots by harvesting above-ground plant parts. In each plot, two squares were randomly chosen and all biomass in this square was collected. Plant biomass was sorted in to following groups: dwarf birch, billberry, Salix herbacea, Salix spp, graminoids, herbs, lichens, mosses and dwarf shrub. Before weighing the plant material, it was stored in paper bags at room temperature and then dried for 48 h at 40°C. In order to detect fertilisation effects, all bilberry shoots that had been produced during the actual summer were separately weighted when analyzing the plant biomass. The result showed that the invertebrate community in this area is dominated by carnivores while detritivores, parasitoids and herbivores are quite rare, this was in accordance with previous studies made in the area. Litter manipulation did not create any significant variation in the community structure, but there was a slight tendency that carnivore biomass increased and biomass of herbivores decreased when litter was added to the system. In contrary to this, gracing activity especially on dwarf willow (Salix herbacea) increased in plots were 100 % and 200 % more litter was added. There is a positive correlation between biomass of herbivores and detritivores but the reason for this seems unclear. No fertilisation effect was detected in litter manipulated plots. The structure and dynamics of the actual community could not be described by the food web theory EEH and energy shunt from litter and apparent competition between herbivores and detritivores. It seems to be several complicating factors to take into consideration when describing this community.

As climate-driven changes in phenology are becoming more apparent, the need to quantify these changes is increasing. An important challenge in detecting phenological changes is that between-year variation in phenology is large. Between-year variation determines the statistical power of comparisons between contemporary and historical observations. For 44 plant species with different distributions across Sweden, geographicand inter-specific differences in between-year variation in different phenophases (budburst, flowering, ripe fruits, and leaf fall) was studied. I also modeled and evaluated theresponse of bud burst, and flowering, to temperature using three different temperature sum models over a latitudinal gradient. The data used was a sub-sample from a dataset collected by a Swedish nation-wide phenology network between 1873-1917. In agreement with previous studies, I show that early spring phases have a higher variability than phases occurring later in the season. However, the relation between onset and variation was not monotonically decreasing. In the geographical analyses, a unimodal relation between between-year variation and latitude was found, that is, the between-year variation decreased along the latitudinal gradient for early- and late season events, while it increased over latitude for summer events. These patterns are, to a great extent, reflections of patterns in air temperatures which is discussed using meteorological data from adjacent climate stations. Models were evaluated using Akaike's Information Criterion, and in 60% of all fits, the Spring warming CF2 model (SWCF2; the model with the least number of parameters) was selected as the best model to describe the data. For Sorbus aucuparia bud burst, in the two parameter model SWCF2, both parameters (threshold temperature andtemperature sum) correlated with latitude. However, future analysis using more locations and a wider span of species will be needed to understand the generality in these findings. In conclusion, future efforts to detect and quantify phenological changes need to consider differences in between-year phenological variability along geographical gradients and among species with different phenology.

No description available.

No description available.

<p>Three species of burnet moths (<em>Zygaena</em> <em>filipendulae</em>,<em> Z</em>. <em>lonicerae</em> and <em>Z</em>. <em>viciae</em>) were studied on the Baltic island Öland, Sweden, in order to reveal the habitat requirements of different life stages. Larvae were found among a higher cover of their most important host plant, <em>Lotus corniculatus</em>, <em>Trifolium medium</em>/<em>pratense </em>or<em> Vicia </em>spp., than were pupae or imagines, and were also observed on plants larger than randomly examined plants. Imagines actively selected nectar plants of <em>Centaurea </em>and <em>Cirsium</em>, growing in sunny conditions, but other red and violet Asteraceae flowers were also favoured. Pupae of <em>Z</em>.<em> filipendulae</em> appeared in taller vegetation than larvae and imagines, probably because the cocoons are spun high on stems of grasses and other plants. The chance of finding such suitable substrates rises with increasing vegetation height. A large scale analysis of occupancy patterns was also made, evaluating the relationship between burnet presence or absence and the area of meadows and pastures within 10 x 10 km grid cells in southern Sweden. All three species showed a positive relationship with increasing area of semi-natural grassland. Thresholds for the amount of habitat, below which the likelihood of occurrence declined more rapidly, could be distinguished around a 40-50 % probability of occurrence. Conservational work should aim at preserving and restoring open and sunny areas, rich in the respective host plants and nectar sources, but vegetation management must be executed with great care or late in the season to not harm unhatched pupae and to maintain substrates suitable for <em>Z</em>. <em>filipendulae</em> pupation.</p>

<p>The tropical palm <em>Mauritia flexuosa </em>has highly nutritious fruits and is an important food resource for both humans and wildlife throughout its geographic range in South America. Unsustainable harvesting threatens wild populations. <em>Mauritia f</em>. occurs primarily in wetlands called Aguajales where it can become the dominating canopy species. Seed predation and dispersal can dramatically affect the survival and distribution of plant species in tropical rainforests (Janzen 1970, Connell 1971, Bleher & Böhning-Gaese 2001, Paine & Beck 2007, Mari et al. 2008). Increased knowledge of seed predation and germination requirements is essential for successful management of this commercially and ecologically important palm. Four experiments were conducted in Manu National Park in southeastern Peru to study: (1) Seed survival in the Aguajal, (2) Quantify seed predators on dry land, (3) Insect visitors and consumers of fruits and seeds, and (4) Germination in greenhouse experiments. Seed survival was significantly higher below water compared to on dry micro sites within the Aguajal. Seeds and fruits placed on dry land were preyed upon by both insects and mammals. Terrestrial insects were the most important predators. Different insects visited fruits and seeds, indicating a successive breakdown of different tissues. Seed survival was also higher below water and/or soil in the greenhouse experiment. This may suggest that the distribution of <em>Mauritia f</em>. is highly influenced by seed predation and that water protects seeds from their insect enemies.</p>

<p>In 1994 a new Forestry Act was accepted in Sweden. One of its aims was to raise the consideration for preservation of biodiversity. Since this happened over 15 years ago there is now an interest in analyzing if the law has been effective in its purpose. In this study methods suitable for analysis are being investigated. The study contents a pilot study of methods for five parameters that can validate if the law has been followed. The fieldstudy were executed in Orsa, Dalarna, Sweden in a managed forest and where last clearcut was done after 1994. The work consisted of measuring the parameters in the field and to compare them with data from before 1994. The benefits of the parameters and the current and previous Forestry Act and their differences are discussed in the report. The parameters examined were the distribution of tree species, standing dead wood, smaller areas saved for preservation, big trees and trees with cavities/cavernous trees. All of these plus a few other variables favourable for the diversity of species in the forest are dealt with in the 30 § in the Forestry Act of 1994. The study implied that the variables reported to be favourable for biodiversity, and possible to investigate within the restrictions of this study, seemed to have increased. The results should however be interpreted with care since the study is small and the reference values sometimes were missing or covering larger areas than the field data.</p>

No description available.

<p>Modern methods for managing pine (<em>Pinus sylvestris</em>) create homogenized forests. This decreases nature’s potential for biodiversity and might threaten species in need of different types of milieu. The main purpose of this study was to investigate how important older pine trees are for biodiversity. In the Hall-Hangvar Reserve in the north-west part of Gotland, insects collected from traps showed that more species were found in old or dead trees compared to younger pine trees. A statistically significant difference was found for Coleoptera (beetles). The taxons of greatest interest for this study were Coleoptera and Hymenoptera (wasps). Certain families of Hymenoptera use ducts made by larvae from some families of Coleoptera.These larvae also serve as prey. Relevance concerning enviromental importance to species and diffrenences in inhabiting the three stages of pine trees was of importance.</p>