Browsing by Subject "Indicator species"

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  • Burner, Ryan C.; Birkemoe, Tone; Stephan, Jorg G.; Drag, Lukas; Muller, Joerg; Ovaskainen, Otso; Potterf, Maria; Skarpaas, Olav; Snall, Tord; Sverdrup-Thygeson, Anne (2021)
    Wood-living beetles make up a large proportion of forest biodiversity and contribute to important ecosystem services, including decomposition. Beetle communities in managed southern boreal forests are less species rich than in natural and near-natural forest stands. In addition, many beetle species rely primarily on specific tree species. Yet, the associations between individual beetle species, forest management category, and tree species are seldom quantified, even for red-listed beetles. We compiled a beetle capture dataset from flight intercept traps placed on Norway spruce (Picea abies), oak (Quercus sp.), and Eurasian aspen (Populus tremulae) trees in 413 sites in mature managed forest, near-natural forest, and clear-cuts in southeastern Norway. We used joint species distribution models to estimate the strength of associations for 368 saproxylic beetle species (including 20 vulnerable, endangered, or critical red-listed species) for each forest management category and tree species. Tree species on which traps were mounted had the largest effect on beetle communities; oaks had the most highly associated beetle species, including most of the red-listed species, followed by Norway spruce and Eurasian aspen. Most beetle species were more likely to be captured in near-natural than in mature managed forest. Our estimated associations were compatible ? for many species ? with categorical classifications found in several existing databases of saproxylic beetle preferences. These quantitative beetle-habitat associations will improve future analyses that have typically relied on categorical classifications. Our results highlight the need to prioritize conservation of near-natural forests and oak trees in Scandinavia to protect the habitat of many red-listed species in particular. Furthermore, we underline the importance of carefully considering the species of trees on which traps are mounted in order to representatively sample beetle communities in forest stands.
  • Weckström, Kaarina; Roche, Benjamin Redmond; Miettinen, Arto; Krawczyk, Diana; Limoges, Audrey; Juggins, Steve; Ribeiro, Sofia; Heikkilä, Maija (2020)
    A long-term perspective is essential for understanding environmental change. To be able to access the past, environmental archives such as marine and lake sediments that store information in the form of diverse proxy records are used. Whilst many analytical techniques exist to extract the information stored in these proxy records, the critical assessment and refinement of current methods in addition to developing new methods is crucial to improving our understanding. This study aims to improve our knowledge on diatom species used for reconstructing ocean surface conditions, especially temperature and sea ice variability over time. We define the distribution and the relationship to sea surface temperature (SST) and sea ice concentrations (SIC) of the species Fragilariopsis oceanica, Fragilariopsis reginae-jahniae and Fossula arctica using diatom training sets from the northern North Atlantic. We further assess the effect of separating these species compared to grouping them under F. oceanica, as has been done in the past. Our results suggest that while these three species share similarities such as the preference for stratified waters induced by sea ice or glacier meltwater, they also exhibit heterogeneous distributions across the northern North Atlantic, with individual optima for SST and SIC. This also affects quantitative reconstructions based on our data, resulting in lower SST and higher SIC estimates when the species are separated in the surface sediment and down-core diatom assemblages.
  • Santangeli, Andrea; Girardello, Marco (2021)
    Stemming from a pervasive lack of knowledge on biodiversity, important areas for conservation are typically identified using a subset of well known species, commonly termed surrogate or indicator groups. Birds have been commonly used as biodiversity surrogates due to the good level of knowledge on their taxonomy, ecology and distribution. Raptors in particular have been often proposed as an effective surrogate for other biodiversity based on their dietary diversity, being at the top of the food chain, their preference for highly productive areas, their generally threatened status and high public appeal. However, so far the surrogacy effectiveness of raptors has been largely studied locally or using a narrow selection of surrogate and surrogated taxa. Here we use a spatial conservation planning tool to quantify the surrogacy performance of raptors, overall and by different raptor groups (hawks and eagles, falcons, vultures, owls) to represent important biodiversity areas (such as IUCN protected areas and key biodiversity areas), wilderness areas and the worlds ecoregions. We compared the above surrogacy performance with that of all other non-raptor avian species. We show that raptors perform marginally worse than all other avian species in representing important biodiversity areas and ecoregions. However, raptors representation for wilderness areas was similar or slightly better compared to that of using all non-raptor birds. We also report a large variation in the representation performance by the four raptor groups. Falcons had a particularly high potential in representing protected areas and wilderness areas, equaling or largely surpassing the representation potential provided by all raptors and all other non-raptor birds. Overall, the results suggest that raptors, and particularly falcons, can perform relatively well in representing some important areas for conservation, such as protected areas and wilderness areas, but are relatively poor surrogates for key biodiversity areas and ecoregions. These rather contrasting results call for caution on the use of raptors as global surrogates of wider biodiversity.