Variation in intrinsic (body mass, reproductive condition) and extrinsic factors (habitat quality, spatiotemporal variation in food availability) can affect the costs and benefits of personality traits. Relationships between personality and fitness components can vary with changes in population density and/or habitat quality. Here, using capture-mark-recapture data of individually marked Eurasian red squirrels (Sciurus vulgaris), we explored whether indices of boldness and exploration are correlated with local survival in either of the sexes and with a measure of reproductive success in females, under different conditions of food availability. PCA scores derived from the number of captures (trappability) and number of different traps where an individual was captured (trap diversity), in the first one or two years of presence, were used as indices of personality (boldness and pure exploration). The relationships between boldness and local survival differed between habitats in both sexes. Bold squirrels survived better than shy ones in Norway spruce forest, while in the other two study areas (Scots pine, or mixed spruce-fir forest) survival was lower for bolder squirrels. Pure exploration behavior was negatively correlated with local survival in all habitats and in both sexes. Female reproductive success increased with body mass and decreased with the tendency to explore, a relationship consistent across habitat types. Bolder females did not have a reproductive advantage in years of poor food availability. We suggest that costs and benefits of boldness vary with spatio-temporal differences in availability of high-quality food resources which may help to maintain variation in personality in red squirrels in heterogeneous landscapes.
Temporal patterns of masting in conifer species are intriguing phenomena that have cascading effects on different trophic levels in ecosystems. Many studies suggest that meteorological cues (changes in temperature and precipitation) affect variation in seed-crop size over years. We monitored cone crops of six conifer species in the Italian Alps (1999–2013) and analysed which seasonal weather factors affected annual variation in cone production at forest community level. Larch, Norway spruce and silver fir showed masting while temporal patterns in Pinus\ud sp. were less pronounced. We found limited support for the temperature difference model proposed by Kelly et al. Both seasonal (mainly spring and summer) temperatures and precipitations of 1 and 2 years prior to seed maturation affected cone-crop size, with no significant effect of\ud previous year’s cone crop. Next, we estimated future forest cone production until 2100, applying climate projection (using RCP 8.5 scenario) to the weather model that best predicted variation in measured cone crops. We found no evidence of long-term changes in average cone production\ud over the twenty-first century, despite increase in average temperature and decrease in precipitation. The amplitude of predicted annual fluctuations in cone production varies over time, depending on study area. The opposite signs of temperature effects 1 and 2 years prior to seed set show that temperature differences are indeed a relevant cue. Hence, predicted patterns of masting followed by 1 or more\ud years of poor-medium cone production suggest a high degree of resilience of alpine conifer forests under global warming scenario
Populations on the limits of species' distribution can show different behavioral adaptations to strong ecological pressure than in the central part of the range. We investigated space use patterns of alpine mountain hare (Lepus timidus) at two areas on the southern edge of the species' range. We monitored 34 hares between 2005 and 2008, estimating home range size, overlap, and site fidelity, and compared our results with space use in Scottish and North-European populations. Home ranges of mountain hares did not differ between two study areas with different habitat types. Subadult animals used larger ranges than adults and both age groups reduced home range size in autumn, a period that might be critical for hares due to changes in diet and/or high energy expenditure during the previous breeding season. Home ranges in these alpine populations were smaller than in Scandinavian populations but within the range of populations in different habitat types in Scotland. Seasonal home ranges overlapped considerably, but differed among the sexes: male-female overlap was higher than same sex (male-male and female-female) spatial overlap. Seasonal shifts of home ranges were small, and site fidelity remained high over the seasons, suggesting that resource distribution remained constant throughout the year and that the knowledge of an intensively frequented area is an important element of habitat quality. We concluded that habitat structure and availability of mates interact in affecting mountain hare space use in alpine habitats.
Estimating density, age and sex structure of wild populations is a key objective in wildlife management. Live trapping is frequently used to collect data on populations of small and medium-sized mammals. Ideally, sampling mammal populations by live capturing of individuals provides a random and representative sample of the target population. Trapping data may, however, be biased. We used live-capture data from mountain hares Lepus timidus in Scotland to assess sampling bias between two different capture methods. We captured hares using baited cage traps and long nets on five study areas in the Scottish Highlands. After controlling for the effects of body size, individuals caught in traps were lighter than individuals caught using long nets, suggesting that the body condition of hares differed between the capture methods. This tendency may reflect an increased risk-taking of individuals in poorer body condition and less aversion to entering traps in order to benefit from eating bait. Overall, we caught more adult hares than juveniles and more female hares than males. Our results show that estimates of density and population structure of mountain hares using livecapture data could be affected by the capture method used. We suggest that live-capture studies employ more than one capture method and test for heterogeneity in capture probability to minimise potential bias and achieve reliable estimates of population parameters.
When alien species introduced into a new environment have a strong niche overlap with ecologically similar native species, interspecific competition can cause a decrease in abundance and distribution of native species. Pallas’s squirrel (Callosciurus erythraeus) was introduced in Northern Italy where it currently co-occurs with native Eurasian red squirrels (Sciurus vulgaris). The alien species is known for its invasiveness but so far negative effects of Pallas’s squirrels on native tree squirrels have not been demonstrated. Here, we compare demographic parameters of red squirrel populations between sites without (red-only sites) and with (red-Pallas’s sites) C. erythraeus and present results of trapping and removal of Pallas’s squirrel and its effects on red squirrel population dynamics. The native species was patchily distributed and absent in many trapping sites occupied by the Pallas’s squirrel. Red squirrels occurred at much lower densities and showed reduced adult survival in areas of co-occurrence than in red-only sites, but there were no differences in reproductive rate. Removing invasive squirrels throughout the study period resulted in re-colonisation by the native species only in some trapping sites, and several alternatives to explain the lack of a marked increase in population size are discussed. This study is the first to provide evidence that presence of Pallas’s squirrel reduces viability of local red squirrel populations
The EU Regulation no.1143/2014 on invasive species requires the EU Member States to respond promptly and efficiently in eradicating the invasive alien species listed as species of Union concern. The Northern raccoon (Procyon lotor) was introduced in Northern Italy along the river Adda and we carried out its eradication campaign between 2016 and 2019. We used an integrated approach of camera traps and live traps. A standardized approach to the camera trap survey (2904 camera trap-nights) revealed that the detectability of raccoons (0.27 ± 0.07 SD) increased in the proximity of the river and their occupancy (0.15 ± 0.09 SD) was higher in urban areas. These results allowed us to increase the trapping success whilst reducing the effort. During the captures, systematic collection of catch and effort data allowed to estimate population size (65 ± 7.8 raccoons) and thus to have a continuous update on how far the campaign was from the complete eradication of the species, allowing to adjust the trapping effort accordingly. We captured 69 raccoons (7279 cage trap nights) thanks to both systematic trapping and opportunistic activation of traps following stakeholders' reports. Stakeholders supported the campaign and some of them played an important role in reporting sightings, signs, and allowing access to their private land. Camera trap data also allowed us to make a Rapid Eradication Assessment that estimated an eradication probability of 99% after 6 months without detections. We finally give indications for future control campaigns on the species to increase removal success, reducing the effort.
& Key message Climate factors affect seed biomass production which in turn influences autumn wild boar spatial behaviour. Adaptive management strategies require an understanding of both masting and its influence on the behaviour of pulsed resource consumers like wild boar. & Context Pulsed resources ecosystem could be strongly affected by climate. Disantangling the role of climate on mast seeding allow to understand a seed consumer spatial behaviour to design proper wildlife and forest management strategies. & Aims We investigated the relationship between mast seeding and climatic variables and we evaluated the influence of mast seeding on wild boar home range dynamics. & Methods We analysed mast seeding as seed biomass production of three broadleaf tree species (Fagus sylvatica L., Quercus cerris L., Castanea sativa Mill.) in the northern Apennines. Next, we explored which climatic variables affected tree masting patterns and finally we tested the effect of both climate and seed biomass production on wild boar home range size. & Results Seed biomass production is partially regulated by climate; high precipitation in spring of the current year positively affects seed biomass production while summer precipitation of previous year has an opposite effect. Wild boar home range size is negatively correlated to seed biomass production, and the climate only partially contributes to determine wild boar spatial behaviour. & Conclusion Climate factors influence mast seeding, and the negative correlation between wild boar home range and mast seeding should be taken into account for designing integrated, proactive hunting management.
The effects of human disturbance represent one of the major threats for wildlife conservation. Many studies have shown that wildlife avoids or reduces direct contact with human activities through changes in activity patterns, and by minimizing spatiotemporal overlap. In this study, we investigated the possible effects of human presence on the temporal activity of medium-to-large mammals using two areas in Myanmar that differ in the intensity of human disturbance. We monitored temporal segregation mechanisms using camera trapping data and with two statistical approaches: daily activity overlaps between humans and wildlife and circular statistics. We did not find a significant difference in overlapping activity between areas but, thanks to circular statistics, we found that some species show changes in activity patterns, suggesting temporal avoidance. We observed that the daily activity of five species differed between areas of Myanmar, likely adopting mechanisms to reduce overlap in areas highly frequented by humans. Interestingly, these species are all threatened by hunting or poaching activities, four of which have been described in literature as “cathemeral”, or species that are active through day and night. This study suggests that some species adapt their behavior, at least partially, to avoid human presence in habitats with higher anthropic occurrence and increase our knowledge on the status of medium–large mammals in a poorly studied country as Myanmar.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.