Circadian Activity Patterns of Canada Lynx in Western Montana

Abstract: We recorded activity data for 6 male and 5 female lynx in winter and 3 male and 6 female lynx during summer in western Montana, USA, using motion-sensitive radiocollars. Lynx diel activity appeared to vary by sex, season, and reproductive status. During summer, male lynx exhibited a crepuscular activity pattern, whereas females with kittens remained active throughout the photoperiod. During winter, lynx of both sexes were most active during the afternoon and early evening. Although we observed no evidence that predation risk drove lynx activity patterns, such patterns may be a function of kitten-rearing activity, thermoregulatory strategies, and foraging behavior.     

A systematic review into the suitability of urban refugia for the Eurasian red squirrel Sciurus vulgaris

1. Urban growth and intensification are projected to increase as the global human population increases. Historically, urban areas have been disregarded as suitable wildlife habitat, but it is now known that these areas can be biodiverse and that wildlife species can adapt to the environmental conditions. One such urban-dwelling species is the Eurasian red squirrel Sciurus vulgaris, which has suffered population declines in several countries throughout its range in recent decades.
2. The current published literature was systematically reviewed to determine whether or not urban habitats are suitable refugia for red squirrels, through identifying and discussing key topics regarding the urban ecology of red squirrels.
3. Urban environments can support higher population densities of red squirrels than rural areas, probably due to the widespread and reliable provision of anthropogenic supplemental food alongside natural food sources. The availability and quality of urban greenspaces are important determinants of the suitability of urban habitats for red squirrels, as they provide natural food sources and nesting sites. Despite the barriers present in urban landscapes (e.g. roads), red squirrels can still disperse and maintain gene flow at the population level.
4. Road traffic accidents appear to be a significant cause of mortality in some urban red squirrel populations, and seasonal peaks of mortality occur during the autumn months. Diseases (e.g. squirrelpox virus) can also be a significant cause of mortality, although effects differ between populations and depend on whether grey squirrels Sciurus carolinensis are present. Many of the predation events that affect red squirrels appear to be due to free-ranging domestic and feral cats Felis catus, although there is currently little evidence to suggest that predation is a limiting factor for urban red squirrel populations.
5. We conclude that urban areas can be suitable refugia for red squirrels, provided that high-quality greenspaces are maintained. Mitigation measures may also be necessary to reduce population mortality and to prevent disease outbreaks.

     

Seasonal climatic niches diverge in migratory birds

Migratory birds occupy different geographical areas during breeding and non-breeding periods, and thus different factors may determine their range limits depending on each season. One such factor is the spatial climatic component of the niche, which is widely used to model species distributions, yet the temporal component is often neglected and is generally assumed to be constant. We tested the hypothesis that the climatic niche is conserved between breeding and non-breeding areas in 355 bird species migrating through Eurasian–African flyways. For this, we performed niche overlap analyses and compared niche differences between sister or phylogenetically closely related species, as well as linking the differences to migratory distances. For more than 80% of the species, there was no or very little overlap between their breeding and non-breeding climatic niches. For most closely related species, the degree of overlap of their breeding climatic niches was larger than the overlap observed within each species, but not for their wintering climatic niches, suggesting a phylogenetic conservation of breeding climatic niches. Finally, there was a clear negative relationship between migratory distances and climatic niche overlap within each species. Our results confirmed that the climatic niche of most Eurasian–African migratory species differs between both breeding and non-breeding ranges, suggesting distinctive seasonal climatic requirements. Given these results and the geographically uneven effects of climate change, the impact of global change is likely to have different effects in each seasonal range. Hence, both breeding and non-breeding climatic data need to be considered when using species distribution models.     

Locomotion of the Eurasian nuthatch on vertical and horizontal substrates

Legged locomotion of the Eurasian nuthatch Sitta europaea on horizontal and vertical substrates was examined using field observations and experiments. Although previous studies have reported that nuthatches use 'walking' on vertical substrates, we found that they usually used 'hopping' on both vertical and horizontal substrates. When climbing up a vertical substrate, the feet were staggered in position and small phase differences were observed between the left and right leg movements in the gait. In upward climbing, the body was inclined towards the substrate during the first stance phase similar to other tree-trunk climbers, but the tail was not used for helping body rotation unlike most tree-trunk climbers. The staggered position of the feet may allow the legs to play different roles in pulling towards and pushing away from the substrate. In downward climbing, the feet were staggered in position, but the phase difference was quite small. In field observations, the Eurasian nuthatch preferred to move vertically, rather than in an inclined direction.     

Effects of Species Behavior on Global Positioning System Collar Fix Rates

ABSTRACT Use of Global Positioning System (GPS) telemetry is increasing in wildlife studies and has provided researchers and managers with new insight into animal behavior. However, performance of GPS collars varies and a major concern is the cause of unsuccessful fixes. We examined possible factors causing missed fixes in GPS collars on sympatric free-ranging Eurasian lynx (Lynx lynx) and wolverines (Gulo gulo) in northern Sweden. We tested for effects of species, activity, habitat, individual, and collar on fix rate. Species was the most important factor affecting fix rate. Fix rate of GPS collars on lynx (80%) was almost twice as high as on wolverines (46%). Fix rate decreased during periods of low activity (day beds) for both species. Fix rate also decreased for females (both lynx and wolverine) for a period after they gave birth. We found no effect of proportion of forest within individual home range on fix rate. We conclude that species behavior, characteristics, and activity pattern are important factors affecting fix rate that we recommend be taken into consideration prior to analyzing GPS location data.     

Sampling characteristics of two methods for capturing age-0 fish in pelagic lake habitats

For the capture of rapidly developing and fast growing age-0 Perca fluviatilis , a sampling precision of <0·2 could be achieved with both push-netting and purse seining. Night catches obtained from purse seining showed predominantly and sometimes significantly higher densities. The push-net system was appropriate for capturing newly hatched larvae and juveniles up to c. 30 mm L_T. The small purse seine was appropriate for fish of 14–30 mm. For perch >30 mm, a 120×5 m purse seine was most suitable.     

Poor fossil record and major changes around 1 MaBP

The abundance of early fossil humans in African sites ceases at dates around 1.3MaBP; there is almost none until nearly 0.8MaBP. Again these are scarce until less than 0.5 Ma. Most of Homo erectus fossils in Java are dated between c.1.3 and 0.70Ma; just a few fossil humans are known in Eurasia for this time span. Questions arise on eventual environmental constraints, that may have influenced evolutionary crises of human populations, but also on geographic conditions adverse to fossilization processes and/or site formation. Records on climate variables, vegetation, sea level, sedimentary conditions and tectonic behavior in regions of the Old World are collected, and correlation traced back in time slices. Continental accretion is related to end of sedimentation in African basins; repeated compressive tectonic activity negatively affected preservation of both fossils and occupation sites widely, before and immediately after the M/B reversal. Lithic artefact assemblages, although derived, are understood as evidence of human occupation in the studied interval. Human populations are exspected to be affected by environmental changes, small, and scattered. Origin of Homo sapeins and divergence of preneandertalians are driven back to those times. Ancestorship to the latter is found probably in African fossils of that time span. Modern traits found in the Atapuerca-TD6 sample and the preceeding considerations urge research on humans and their movements intra- and intercontinental around 1 MaBP.