The catscape: spatial manifestation of a pet cat population with outdoor access

The domestic cat (Felis catus) is the most popular companion animal and the most abundant carnivore globally. It is also a pet with an immense ecological footprint, because even non-feral and food-subsidized cats are prolific predators. Whereas knowledge about the spatial behavior of individual domestic cats is growing, we still know little about how a local population of free-ranging pet cats occupies the landscape. Using a citizen science approach, we GPS-tagged 92 pet cats with outdoor access living in a residential area in southern Norway. The resulting position data allowed us to construct both individual home range kernels and a population-level utilization distribution. Our results reveal a dense predatory blanket that outdoor cats drape over and beyond the urban landscape. It is this population-level intensity surface - the catscape - that potential prey have to navigate. There were almost no gaps in the catscape within our residential study area and therefore few terrestrial refuges from potential cat predation. However, cats spent on average 79% of their outdoor time within 50 meters to their owner's home, which suggests that the primary impact is local and most acute for wildlife in the vicinity to homes with cats. We discuss the catscape as a conceptual and quantitative tool for better understanding and mitigating the environmental impact of domestic cats.

The influence of night length: Activity of the northern bat Eptesicus nilssonii under conditions of continuous light in midnight sun compared to a southern population

Background Nearly all insectivorous bats (Chiroptera) are strictly nocturnal, flying and feeding only between sunset and sunrise despite lower insect availability than by day, most likely to avoid predation by diurnal birds. This may represent a great challenge to bats living north of the Arctic Circle, which are exposed to bright nights in the period of the midnight sun. The northern bat Eptesicus nilssonii was studied at different latitudes in Norway (69, 66 and 58°N) by three techniques; visual counts of exits from and returns to roosts, infrared detection with a datalogger and an ultrasound data recorder, to reveal how their activity varied across latitude, season, and night, as well as across light levels. How does a nocturnal bat adjust to perpetual light and what light levels are tolerated? Results In the north the bats’ active season lasted 2.5 months, 1.5 months shorter than in the south. The bats only flew in 3-4 weeks of midnight sun, and hardly ever left the roost until the sun went behind a hill in the evening. In addition, the timing of their nightly hunting was highly influenced by the darkness of the sky, and they very rarely flew in light levels above 200 foot-candles (FC). As the night became darker than twilight from early August, the bats restricted their activity to between sunset and sunrise. This was the normal situation in southern Norway, where the bats tracked sunset and sunrise throughout the entire season. Those bats appeared to prefer light levels below 100-50 FC and hence, also did fly in twilight conditions. Conclusions The willingness to fly in twilight by the southern population may be a prerequisite to the northern bat’s survival in the land of the midnight sun. These bats must accept short nights in the first part of their summer season and must be willing to fly in light levels 2-4 times higher than in the south. Most likely, this depends on a reduced predation risk and good abundance of insects at night.

A Forest Pool as a Habitat Island for Mites in a Limestone Forest in Southern Norway

Forest water bodies, e.g., pools, constitute ‘environmental islands’ within forests, with specific flora and fauna thus contributing considerably to the landscape biodiversity. The mite communities of Oribatida and Mesostigmata in two distinctive microhabitats, water-soaked Sphagnum mosses at the edge of a pool and other mosses growing on the medium-wet forest floor nearby, were compared in a limestone forest in Southern Norway. In total, 16,189 specimens of Oribatida representing 98 species, and 499 specimens of Mesostigmata, from 23 species, were found. The abundance and species number of Oribatida were significantly lower at the pool, while the abundance and species richness of Mesostigmata did not differ. Both the communities of Oribatida and of Mesostigmata differed among the microhabitats studied and analysis showed significant differences between the community structures in the two microhabitats. The most abundant oribatid species in Sphagnum mosses was Parachipteria fanzagoi (Jacot, 1929), which made up over 30% of all Oribatida, followed by Atropacarus striculus (C.L. Koch, 1835) and Tyrphonothrus maior (Berlese, 1910) (14% and 12% of Oribatida, respectively). Among Mesostigmata Paragamasus parrunciger (Bhattacharyya, 1963) dominated (44% of Mesostigmata), followed by P. lapponicus (Trägårdh, 1910) (14% of Mesostigmata). Most of these species, except P. lapponicus, were either absent or very uncommon in the other microhabitat studied. The specific acarofauna of the forest pool shows the importance of such microhabitats in increasing forest diversity. In addition, a quarter of the mite species found had not been reported from Norwegian broadleaf forests before, including five new species records for Norway and four new to Fennoscandia, all found in the medium-wet microhabitat. Most of these species are rarely collected and have their northernmost occurrence in the studied forest.

Host in reserve: the role of common shrews (Sorex araneus) as a stable supplementary source of tick hosts in small mammal communities influenced by rodent population cycles

In recent decades, warming temperatures and changes in land use are supposed to have enabled several tick species to expand their distribution limit northwards. The progression of ticks to new areas may introduce new and emerging tick-borne pathogens as well as increase existing diseases. Aside from climatic conditions, ticks are dependent on hosts for survival, and rodents often act as important hosts for ticks and as pathogen reservoirs. At northern latitudes, rodents often undergo multi-annual population cycles, and the periodic absence of hosts may inhibit the further progression of ticks. We investigated the potential role of common shrews (Sorex araneus) to serve as a stable host source to immature life stages of a generalist tick Ixodes ricinus and a specialist tick I. trianguliceps, during decreasing abundances of bank voles (Myodes glareolus). We tested whether ticks would have a propensity to parasitize a certain host type dependent on host population size and composition in two high latitude locations in southern Norway, by comparing tick burdens on trapped animals. We found that I. ricinus larvae showed an equal propensity to parasitize both host types as the host population composition changed, but voles had a higher level of parasitism by nymphs (p< 0.004). An overall larger host population size favored the parasitism of voles by larvae (p= 0.027), but not by nymphs (p= 0.074). I. trianguliceps larvae showed a higher propensity to parasitize shrews, regardless of host population size or composition (p= 0.004), while nymphs parasitized shrews more as vole abundance increased (p= 0.002). The results indicate that common shrews may have the potential to act as a replacement host during periods of low rodent availability, but long-term observations encompassing complete rodent cycles may determine whether shrews are able to maintain tick range expansion despite low rodent availability.

Could Norwegian fjords serve as an analogue for the future of the Svalbard fjords? State and fate of high latitude fjords in the face of progressive “atlantification”

Benthic foraminifera are one of the most widely and abundantly distributed organisms in the fjords of Svalbard and Norway. Due to their short life span and quick reactivity to environmental changes they can be used as indicators of the “atlantification” process. Here, we compare the benthic foraminifera assemblages along the latitudinal gradient, from the fjords of northern Svalbard to southern Norway to assess whether the “atlantification” process may homogenise the foraminiferal assemblages in terms of their abundance and species composition. Furthermore, the previously published data on benthic foraminiferal faunas was updated to identify changes in distribution that have occurred over the last few decades. For this purpose, fjord mouths in western and northern Svalbard (Isfjorden, Wijdefjorden and Rijpfjorden) and northern and southern Norway (Balsfjorden, Raunefjorden and Hjeltefjorden) were resampled. The analysis revealed similarities between the Svalbard and Norwegian foraminiferal assemblages of up to 30%; however, there were essential differences in terms of abundance and biodiversity. These results suggest that Svalbard fjords will remain distinct in the future, even under conditions of further warming or “atlantification”. Svalbard fjords may be dominated by Atlantic Water- preferring species, whereas, in Norwegian fjords, pressure from human activity will probably be the main driver of environmental changes, leading to changes in the foraminiferal assemblages with the increasing dominance of opportunistic, hypoxia-tolerant species.

The Association between Dietary Habits, Substance Use and Mental Distress among Adults in Southern Norway: A Cross-Sectional Study among 28,047 Adults from the General Population

The aim of the present study was to examine associations between dietary habits, substance use, and mental distress among adults. This cross-sectional study was conducted in 2019 using an online questionnaire and included 28,047 adults (≥18 years) from Southern Norway. Multivariable logistic regression models stratified by gender were used to examine the associations between different lifestyle behaviors and mental distress. The results showed increased odds of mental distress among males and females with low consumption of vegetables (OR:1.26; 95% CI:1.08–1.47 and 1.14; 1.02–1.28) and fish (1.28; 1.12–1.46 and 1.36; 1.22–1.52), and among females, but not males, with high consumption of sugar-sweetened beverages (1.25; 1.06–1.48) compared to those with a healthier consumption of these foods and beverages. The results also showed increased odds of mental distress among male and female smokers (1.38; 1.19–1.60 and 1.44; 1.26–1.64), and among females, but not males, reporting current use of smokeless tobacco (1.20; 1.03–1.40), compared to male and female non-smokers and female non-users of smokeless tobacco. Overall, unhealthy dietary habits, smoking and the use of smokeless tobacco was associated with increased odds of mental distress, but the relationship varied according to gender. Future studies are needed to confirm any possible causal relationships.

New evidence for active talus-foot rock glaciers at Øyberget, southern Norway, and their development during the Holocene

Synthetic aperture radar interferometry (InSAR) measurements demonstrate that lobate, blocky depositional landforms, located in southern Norway at an altitude of ~530 m above sea level, with an estimated mean annual air temperature of ~1.6°C, currently exhibit deformation attributed to viscous creep. Five years of InSAR measurements for six lobes demonstrate average surface velocities of 1.2–22.0 mm/year with maximum rates of 17.5–55.6 mm/year. New Schmidt-hammer exposure-age dating (SHD) of two proximal lobes reveals mid-Holocene ages (7.6 ± 1.3 ka and 6.0 ± 1.2 ka), which contrast with the early-Holocene SHD and 10Be ages obtained previously from distal lobes, and late-Holocene SHD ages presented here from two adjacent talus slopes (2.3 ± 1.0 ka and 2.4 ± 1.0 ka). Although passive transport of boulders on the surfaces of these small, slow-moving rock glaciers affected by compressive flow means that the exposure ages are close to minimum estimates of the time elapsed since lobe inception, disturbance of boulders on rock glaciers is a source of potentially serious underestimates of rock-glacier age. Rock-glacier development at Øyberget began shortly after local deglaciation around 10 ka before present and continued throughout the Holocene in response to microclimatic undercooling within the coarse blocky surface layer of the talus and rock-glacier lobes. We suggest this enhanced cooling lowers mean annual surface-layer temperature by at least ~3.6°C, which is needed at such a low altitude to sustain sporadic permafrost and avoid fast thawing as atmospheric temperatures rise. Our results point to circumstances where inferences about rock glaciers as indicators of regional climate should be interpreted with caution, and where they may be less useful in palaeoclimatic reconstruction than previously thought.