20 research outputs found
Species-Area Relationships Are Controlled by Species Traits
The species-area relationship (SAR) is one of the most thoroughly investigated empirical relationships in ecology. Two theories have been proposed to explain SARs: classical island biogeography theory and niche theory. Classical island biogeography theory considers the processes of persistence, extinction, and colonization, whereas niche theory focuses on species requirements, such as habitat and resource use. Recent studies have called for the unification of these two theories to better explain the underlying mechanisms that generates SARs. In this context, species traits that can be related to each theory seem promising. Here we analyzed the SARs of butterfly and moth assemblages on islands differing in size and isolation. We tested whether species traits modify the SAR and the response to isolation. In addition to the expected overall effects on the area, traits related to each of the two theories increased the model fit, from 69% up to 90%. Steeper slopes have been shown to have a particularly higher sensitivity to area, which was indicated by species with restricted range (slope â=â0.82), narrow dietary niche (slope â=â0.59), low abundance (slope â=â0.52), and low reproductive potential (slope â=â0.51). We concluded that considering species traits by analyzing SARs yields considerable potential for unifying island biogeography theory and niche theory, and that the systematic and predictable effects observed when considering traits can help to guide conservation and management actions
Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases
Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises
Will climate mitigation ambitions lead to carbon neutrality? An analysis of the local-level plans of 327 cities in the EU
Cities across the globe recognise their role in climate mitigation and are acting to reduce carbon emissions. Knowing whether cities set ambitious climate and energy targets is critical for determining their contribution towards the global 1.5 °C target, partly because it helps to identify areas where further action is necessary. This paper presents a comparative analysis of the mitigation targets of 327 European cities, as declared in their local climate plans. The sample encompasses over 25% of the EU population and includes cities of all sizes across all Member States, plus the UK. The study analyses whether the type of plan, city size, membership of climate networks, and its regional location are associated with different levels of mitigation ambition. Results reveal that 78% of the cities have a GHG emissions reduction target. However, with an average target of 47%, European cities are not on track to reach the Paris Agreement: they need to roughly double their ambitions and efforts. Some cities are ambitious, e.g. 25% of our sample (81) aim to reach carbon neutrality, with the earliest target date being 2020.90% of these cities are members of the Climate Alliance and 75% of the Covenant of Mayors. City size is the strongest predictor for carbon neutrality, whilst climate network(s) membership, combining adaptation and mitigation into a single strategy, and local motivation also play a role. The methods, data, results and analysis of this study can serve as a reference and baseline for tracking climate mitigation ambitions across European and global cities
KartlÀggning av transkador pÄ SöderfjÀrden
Det hÀr slutarbetet handlar om kartlÀggning av transkador pÄ SöderfjÀrden. KartlÀggningen gjordes med en blankettförfrÄgan och med en telefonförfrÄgan. I kartlÀggningen kommer ocksÄ fram hur samexistensen mellan tranor och lantbrukare fungerar.
I blankettförfrÄgan frÄgades det odlare som odlade pÄ söderfjÀrden och i vilken kommun eller stad som jordbrukarna var verksamma. Jordbrukarnas odlingsareal frÄgades ocksÄ och vilka grödor som odlas. Jordbrukarna frÄgades ocksÄ om hur dom upplever samexistensen med tranorna pÄ SöderfjÀrden.
Slutarbetet handlar ocksÄ om hur fÄgelÄkrar fungerar pÄ SöderfjÀrden. I undersökningen om fÄgelÄkeranvÀndningen sÄ frÄgades det av jordbrukare som odlat fÄgelÄker och som inte odlat fÄgelÄker
Early migrartion of acetabular components revised with cement.
Roentgen stereophotogrammetric analysis (RSA) was used to evaluate the migration in 17 cemented acetabular components after revision operations for mechanical loosening. All of the hips were examined four months and one year after surgery; ten of the hips were also examined after two years. In 15 of the 17 components, definite migration (0.5-2.7 mm) was identified, whereas two acetabular components showed no significant migration (< 0.25 mm). In 13 hips, the migration was seen within four months after surgery. There was a tendency for larger migration in revisions for severe bone destruction. These findings indicate that prosthetic fixation in revision operations is relatively poor. In cases with severe bone loss, cement fixations is extremely poor