Mechatronics meets biology: Experiences and first results with a multipurpose small mammal monitoring unit used in red squirrel habitats

Monitoring is a fundamental aspect of species conservation and research. Technological advances, especially with respect to camera trap technologies, have allowed glimpses into unknown aspects of species behaviour and have the potential to greatly assist species distribution monitoring. Here we present the findings of a pilot study combining existing biological monitoring techniques with mechatronics to advance monitoring technologies and develop a multi-purpose, species specific, automated monitoring system. We developed a Small Mammal Monitoring Unit (SMMU) that integrates automated video, and sound recording, carries out body weight measurements and takes hairs samples with a bait station in a portable perspex box. The unit has the potential for use with a range of small mammal species, but has been field-tested here on red squirrels, Sciurus vulgaris, in Germany, Scotland and Switzerland. We successfully collected hair-samples, body mass data as well as video and sound recordings. Preliminary data analyses also revealed behavioural information. Heavier individuals first gained access to the feeder in the morning and have longer feeding bouts. Our prototype demonstrated that the collaboration between mechatronic and biology offers novel, integrated monitoring techniques for a range of research application. The development of units for other mammal species is planned. Future developments will explore the possibilities for wireless data transmission, built-in collection of weather data and collection of images from inside the unit for the recognition of individuals

Wildlife conservation in a fragmented landscape: the Eurasian red squirrel on the Isle of Wight

Island populations may have a higher extinction risk due to reduced genetic diversity and need to be managed effectively in order to reduce the risk of biodiversity loss. The Eurasian red squirrels (Sciurus vulgaris) in the south of England only survive on three islands (the Isle of Wight, Brownsea and Furzey islands), with the Isle of Wight harbouring the largest population in the region. Fourteen microsatellites were used to determine the genetic structure of red squirrel populations on the Isle of Wight, as well as their relatedness to other populations of the species. Our results demonstrated that squirrels on these islands were less genetically diverse than those in Continental mainland populations, as would be expected. It also confirmed previous results from mitochondrial DNA which indicated that the squirrels on the Isle of Wight were relatively closely related to Brownsea island squirrels in the south of England. Importantly, our findings showed that genetic mixing between squirrels in the east and west of the Isle of Wight was very limited. Given the potential deleterious effects of small population size on genetic health, landscape management to encourage dispersal of squirrels between these populations should be a priorit

Body weights in grey and red squirrels: do seasonal weight increases occur in conifer woodland?

Seasonal body weight changes were investigated in red and grey squirrels in spruce-dominated conifer plantations in the north of England. Annual seed food availability, particularly in the spruce plantations, varies markedly and is characterized by years with large cone crops (‘mast crops’) followed by several years of intermediate or low crops. The last mast crop in Kielder Forest District occurred in 1991 and we studied the two squirrel species when food availability was intermediate and low between 1992 and 1999. Neither red nor grey squirrels in the conifer plantations significantly increased their body weight for the autumn or winter. The responses of red and grey squirrels to the different foraging conditions in deciduous and conifer woodlands and the accumulation of seasonal fat stores may have to be seen in the context of habitat type and the pattern and predictability of seed availability. Our findings suggest that fat accumulation is likely to be less pronounced in conifer habitats where autumn and winter food supplies are more predictable, and manoeuvrability to feed on cones in the canopy is importan

Alien species and interspecific competition: effects of introduced eastern grey squirrels on red squirrel population dynamics

1. Throughout much of Britain, Ireland and north Italy, red squirrels ( Sciurus vulgaris L.) have been replaced by alien grey squirrels ( S. carolinensis Gmelin) introduced from North America. We have studied squirrels in two mixed woodlands in north Italy and two conifer forests in north England. In each country, one site was occupied by red squirrels and one site by both species. 2. We have previously considered interference competition and exploitation competition for food and space between red and grey squirrels and have showed that grey squirrels caused reduced body growth in juvenile and subadult red squirrels, and compete for tree seeds cached by adult red squirrels in spring. Here we report on the effects of grey squirrels on three fitness components in red squirrels that have consequence at the population level: fecundity, residency and recruitment. 3. Litter production peaked in the spring and summer, but fewer females bred in the summer with grey squirrels present. In addition, fewer individual red squirrel females produced two litters per year in the sites with grey squirrels. Moreover, red squirrel recruitment rate and, in the mixed broadleaf sites, red squirrel juvenile residency, decreased with increasing grey squirrel density. 4. Fecundity of individual female red squirrels was lower in red\u2013grey than in red-only sites because they had a lower body mass in sites with grey squirrels. 5. Overall, there was no significant effect of grey squirrels on residency of adult red squirrels or on population turnover rate. However, the presence of grey squirrels resulted in a reduction in red squirrel fitness which was evident by lower population summer breeding and a lower recruitment. Over time, this will result in a decline in population size and eventually population extinction.1. Throughout much of Britain, Ireland and north Italy, red squirrels (Sciurus vulgaris L.) have been replaced by alien grey squirrels (S. carolinensis Gmelin) introduced from North America. We have studied squirrels in two mixed woodlands in north Italy and two conifer forests in north England. In each country, one site was occupied by red squirrels and one site by both species.2. We have previously considered interference competition and exploitation competition for food and space between red and grey squirrels and have showed that grey squirrels caused reduced body growth in juvenile and subadult red squirrels, and compete for tree seeds cached by adult red squirrels in spring. Here we report on the effects of grey squirrels on three fitness components in red squirrels that have consequence at the population level: fecundity, residency and recruitment.3. Litter production peaked in the spring and summer, but fewer females bred in the summer with grey squirrels present. In addition, fewer individual red squirrel females produced two litters per year in the sites with grey squirrels. Moreover, red squirrel recruitment rate and, in the mixed broadleaf sites, red squirrel juvenile residency, decreased with increasing grey squirrel density.4. Fecundity of individual female red squirrels was lower in red-grey than in red-only sites because they had a lower body mass in sites with grey squirrels.5. Overall, there was no significant effect of grey squirrels on residency of adult red squirrels or on population turnover rate. However, the presence of grey squirrels resulted in a reduction in red squirrel fitness which was evident by lower population summer breeding and a lower recruitment. Over time, this will result in a decline in population size and eventually population extinction

Planning a red squirrel conservation area: using a spatially explicit population dynamics model to predict the impact of felling and forest design plans

This paper describes the use of a spatially explicit population model (SEPM) to investigate the effects of different forest management strategies on a red squirrel conservation area. The study was based in woodland managed by Forest Enterprise, which manages 75 000 ha of woodlands in Northumberland, Co. Durham, Tyne and Wear, and east Cumbria. The forests contain the largest remaining red squirrel populations in northern England and the area of the study, Kidland Forest, is one of five key areas or refuges where red squirrel conservation is a priority. The SEPM integrates expert knowledge on red and grey squirrels, based on 10 years of fieldwork in the area and information from the scientific literature. We investigated the current tree species composition, distribution and proposed felling plans as well as the future restocking for Kidland Forest, an area of 2050 ha of predominantly conifer species. The assessment also included a proposed planting of 15 ha of oak and its likely consequences on grey squirrel population viability. These results were then applied to develop a forest design plan to ensure red squirrel persistence over the next rotation. Results indicated that red squirrels were at risk of extinction due to a drastic reduction in the availability of suitable habitats through clear-felling. Furthermore the proposed planting of 15 ha of oak could lead to a substantial grey squirrel population at Kidland once the trees matured and assuming that grey squirrels colonize the area. The felling profile was therefore revised, allocating a proportion of the tree crop on more wind-firm sites to long-term retentions. The approach adopted at Kidland illustrates how geographical information systems, expert knowledge on the threatened species and spatially explicit models can be integrated to assist forest managers in assessing the suitability of a site for red squirrel conservation

CLINICAL PROGRESSION OF LEPROSY IN EURASIAN RED SQUIRRELS (SCIURUS VULGARIS) IN A NATURALLY INFECTED WILD POPULATION

Leprosy has been described in Eurasian red squirrel (Sciurus vulgaris; ERS) carcasses since 2014. Studies of ERS carcasses have not provided information about incubation or disease progression in this host but have provided important insights into pathogen presence and distribution throughout the United Kingdom. Here we present field study data on 31 live ERS from an island population naturally infected with Mycobacterium leprae that were assessed longitudinally over a 2-yr time period. Clinical assessment, serologic (anti-phenolic glycolipid-I antibody [alpha PGL-I] detection) and molecular methods (polymerase chain reaction) were used to diagnose and categorize ERS at each assessment as a leprosy case, a leprosy suspect, colonized by M. leprae, or a contact ERS. Eight ERS (25.8%) were identified as leprosy cases: four at initial assessment, two at 6 mon and two at 24 mon after initial assessment. One ERS was categorized a leprosy suspect when it developed typical lesions 12 mon after initial assessment, despite negative serologic and molecular test results at this time, though M. leprae DNA had been isolated during the initial assessment. Seven ERS (22.6%) were categorized as colonized and of these, six were reassessed but did not develop clinical signs of leprosy within 6 (n = 2), 12 (n = 3), and 18 (n = 1) mon. Most (48.4%, n = 15) were categorized as contact ERS. Progression of leprosy lesions varied between ERS, but always increased in severity over time and was paralleled with increased antibody response. Based on our dataset, we propose the hypotheses: 1) leprosy in ERS is a chronic, slowly progressing disease in this species, similar to that described for other hosts; 2) lesions can undergo repeated ulceration-healing cycles; and 3) in some instances M. leprae DNA and alpha PGL-I antibodies are detectable before the onset of clinical signs of disease. Future studies addressing the progression of leprosy in ERS should follow affected animals over a longer time period and include tissue samples to pair molecular diagnostics with serologic results.Immunogenetics and cellular immunology of bacterial infectious disease