Search results for "Cape"

Ilkka Hanski and Small Mammals: from Shrew Metapopulations to Vole and Lemming Cycles

2017

10 pages; International audience; Ilkka Hanski may be best known for his work on insect and metapopulation dynamics, but he also contributed significantly to small mammal research. In the early 1980s he became interested in shrew dynamics, energetics, and of course, shrew metapopulations. He aimed at understanding the population biological consequences of body size in different shrew species. Feeding habits and environmental stochasticity affect shrew species in profoundly different ways: due to their short survival time small species have high extinction rates but their dispersal and colonization capacity is high which enables them to survive as metapopulations. After Hansson and Henttonen…

Fine-Scale Population Differences in Atlantic Cod Reproductive Success: A Potential Mechanism for Ecological Speciation in a Marine Fish

2018

Abstract Successful resource‐management and conservation outcomes ideally depend on matching the spatial scales of population demography, local adaptation, and threat mitigation. For marine fish with high dispersal capabilities, this remains a fundamental challenge. Based on daily parentage assignments of more than 4,000 offspring, we document fine‐scaled temporal differences in individual reproductive success for two spatially adjacent (<10 km) populations of a broadcast‐spawning marine fish. Distinguished by differences in genetics and life history, Atlantic cod (Gadus morhua) from inner‐ and outer‐fjord populations were allowed to compete for mating and reproductive opportunities. After …

Are the effects of an invasive crayfish on lake littoral macroinvertebrate communities consistent over time?

2016

Management of invasive species requires assessment of their effects on recipient ecosystems. However, impact assessment of invasive species commonly lacks a long-term perspective which can potentially lead to false conclusions. We examined the effects of the invasive signal crayfish (Pacifastacus leniusculus Dana) on the stony littoral macroinvertebrate communities of a large boreal lake and assessed the extent to which the patterns observed in previous short-term studies were stable over time. We used temporal macroinvertebrate data collected in five consecutive years from a site with a well-established crayfish population, a site with no crayfish and a site where crayfish had been recentl…

Landowner preferences and conservation prioritization: response to Nielsen et al.

2017

Towards understanding isotope variability in elephant ivory to establish isotopic profiling and source-area determination

2016

Abstract We present here new isotopic data (δ 13 C, δ 15 N, δ 18 O, δ 2 H, and δ 34 S) from pulverised ivory powder, measured by continuous flow isotope ratio mass spectrometry from an unprecedented large dataset of 507 ivory samples, derived from twenty-eight African and six Asian elephant range states. The aim of this study is to assess the accuracy of isotopic fingerprinting and to evaluate its forensic potential and limitations to predict the provenance of ivory of unknown origin. We constructed a nominal assignment framework for the African reference samples, consisting of 208 different sites and applied the weighted k -Nearest Neighbor Classifier with reference site as classifier and …

Occurrence of ‘blue’ and ‘frost’ rings reveal frost sensitivity of eastern Baltic provenances of Scots pine

2020

Abstract Assisted gene flow is advised as one of the most effective means to sustain the productivity of forests under warming climate via application of the provenances (genotypes) capable to utilize longer vegetation season. Nevertheless in the temperate and boreal zones, the extension of vegetation period also subjects trees to effects of frosts, which can have severe economic impact under warming climate. In this study, wood anatomical anomalies related to late frosts in spring (‘frost’ rings) and early frosts in late summer (‘blue’ rings) for the eastern Baltic provenances of Scots pine (Pinus sylvestris L.) with a contrasting field performance were analysed retrospectively. Three tria…

Positive impacts of important bird and biodiversity areas on wintering waterbirds under changing temperatures throughout Europe and North Africa

2020

Clausen, Preben/0000-0001-8986-294X WOS: 000536149100018 Migratory waterbirds require an effectively conserved cohesive network of wetland areas throughout their range and life-cycle. Under rapid climate change, protected area (PA) networks need to be able to accommodate climate-driven range shifts in wildlife if they are to continue to be effective in the future. Thus, we investigated geographical variation in the relationship between local temperature anomaly and the abundance of 61 waterbird species during the wintering season across Europe and North Africa during 1990-2015. We also compared the spatio-temporal effects on abundance of sites designated as PAs, Important Bird and Biodivers…

Northern refugia and recent expansion in the North Sea: The case of the wrasse Symphodus melops (Linnaeus, 1758)

2011

Pleistocene climate changes have imposed extreme conditions to intertidal rocky marine communities, forcing many species to significant range shifts in their geographical distributions. Phylogeographic analyses based on both mitochondrial and nuclear genetic markers provide a useful approach to unravel phylogeographic patterns and processes of species after this time period, to gain general knowledge of how climatic changes affect shifts in species distributions. We analyzed these patterns on the corkwing wrasse (Symphodus melops, Labridae), a rocky shore species inhabiting North Sea waters and temperate northeastern Atlantic Ocean from Norway to Morocco including the Azores, using a fragme…

Persistence of remnant boreal plants in the Chiricahua Mountains, southern Arizona

2020

Abstract Boreal plants growing along the southern edge of their range on isolated mountains in a hot desert matrix live near the extreme of their physiological tolerance. Such plants are considered sensitive to small changes in climate. We coupled field observations (1974, 1993, 2019) about the abundance and vigor of small populations of ten remnant boreal plant species persisting in the uppermost elevations of spruce-fir forests of the Chiricahua Mountains, together with modeling of the species sensitivities to three stress factors associated with climatic change: warming, drought, and forest fire, in order to explore the persistence of frontier boreal plant species during climate change. …

Stand out from the Crowd: Small-Scale Genetic Structuring in the Endemic Sicilian Pond Turtle

2020

The geographical pattern of genetic diversity was investigated in the endemic Sicilian pond turtle Emys trinacris across its entire distribution range, using 16 microsatellite loci. Overall, 245 specimens of E. trinacris were studied, showing high polymorphic microsatellite loci, with allele numbers ranging from 7 to 30. STRUCTURE and GENELAND analyses showed a noteworthy, geographically based structuring of the studied populations in five well-characterized clusters, supported by a moderate degree of genetic diversity (FST values between 0.075 and 0.160). Possible explanations for the genetic fragmentation observed are provided, where both natural and human-mediated habitat fragmentation o…