Csongor I. Gedeon

Nest material selection affects nest insulation quality for the European ground squirrel (Spermophilus citellus)

Abstract Natural nests of the European ground squirrel (Spermophilus citellus) are constructed almost exclusively of fresh fescue (Festuca pseudovina: Poaceae). We performed laboratory experiments to understand the functional significance of preference of wild squirrels for nest material. We examined the factors contributing to nest quality by monitoring the construction and analyzing the composition of squirrel nests. As in the wild, squirrels showed strong preference for fescue during the laboratory tests and preferred fresh material to dry material. Because preference for fresh material was not expected, because high water content reduces insulation, we manipulated the moisture content of nests made from either fresh or dry fescue to determine how nest quality and moisture level contribute to insulation. We found that the insulation property of fresh grass nests was superior to nests constructed from dry grass only. Intracellular water in the nest material did not affect thermal conductance and insulation significantly. We concluded that fresh fescue provided a more flexible material that allows squirrels to construct nests with better insulation under both field and laboratory conditions.

Morphology and function of communal mounds of overwintering mound-building mice (Mus spicilegus)

Mound-building mice (Mus spicilegus) construct large mounds of soil and plant material in autumn, where juvenile animals overwinter in groups without reproducing. The mounds have several functions, including food storage, thermoregulation, and protection from predators. We examined whether these mounds have food storage or thermoregulatory function. Mice used mainly seeds and ears of certain plants (Echinochloa sp., Chenopodium spp., and Setaria spp., depending on availability) as building materials, but microhistological analysis of mice feces revealed that the cached plants are not represented in their actual diet. By comparing the features of soil under the mound to neighboring random points we found that the mounds have water-insulating and thermoregulatory properties. We also found a positive correlation between the size of the mound, its vegetal content, and its effectiveness to lessen the impact of the harsh conditions of the outside environment. Mound size was dependent on the number of inhabitants, indicating that larger mounds are constructed by and shelter bigger groups. The existence of communal mound building thus can contribute greatly to successful overwintering and the relatively low fluctuation in population size in this species.

Release site manipulation to favour European ground squirrel Spermophilus citellus translocations: translocation and habitat manipulation

Translocating European ground squirrels Spermophilus citellus has become a popular conservation tool. However, few release techniques have been carefully evaluated. To contribute to an evidence-based ground squirrel translocation guide for wildlife managers, we evaluated conditions of habitat manipulation (grass height and artificial burrow entrance angle) which we expected to affect settlement of translocated ground squirrels during the critical period after release. In a field experiment, we translocated 173 individuals in southeastern Hungary in 2007. We released the animals into angled or vertical artificial burrows and manipulated grass height. We found that animals preferred angled (∼ 30°) artificial burrows, which facilitate digging, and medium-height grass (18 cm ± 1.5). Moreover, although ground squirrels generally are associated with short grass habitats, overhead protection by grasses is valuable after a translocation. This result implies that in order to accomplish a translocation, it is not sufficient to only know the habitat preference of a species in undisturbed situations, but also how and to what extent habitat characteristics should be manipulated to increase the chances of success.

Importance of Burrow-Entrance Mounds of Gunnison's Prairie Dogs (Cynomys gunnisoni) for Vigilance and Mixing of Soil

Abstract Aboveground mounds and underground burrows are multifunctional and influence behavior and habitat of Gunnisons prairie dogs (Cynomys gunnisoni). Four colonies were studied June–September 2004 to examine function of mounds with respect to vigilance for predators, and to estimate magnitude of soil mixed by these prairie dogs. Frequency of vigilance atop mounds increased in taller vegetation and individuals at perimeters of colonies oriented toward the outside more frequently than to the interior of colonies. Mounds accounted for an average of 10,374 kg of soil/ha that was excavated from the burrow. This mass of subsoil moved to the surface and the 7–17 m3 of air in the burrow make the geomorphic effect of prairie dogs potentially significant.

EDAPHOLOG monitoring system: automatic, real-time detection of soil microarthropods

Summary Soil microarthropods as organic matter decomposers play an important role in soil functioning thus providing ecosystem services. However, ecosystem scale investigations on their abundance and dynamics are scarce because their high spatio-temporal heterogeneity requires huge sample size. Processing and identifying large number of individuals is extremely labour intensive. We prototyped a device called EDAPHOLOG monitoring system that consists of (1) a probe that catches and detects microarthropods and estimates their body size; (2) a data logger transmitting data to a central database, and (3) a Java application for retrieving data. We tested the device in three ways. First, we tested the precision and accuracy of detection and body size estimation of the device in the laboratory using microarthropods of five morphotypes: euedaphic Collembola, haired Collembola, scaled Collembola, Acari and Oribatida. Second, we compared the number of individuals collected by EDAPHOLOG traps, pitfall traps and soil extraction method in an alfalfa field. Third, we deployed a total of 100 EDAPHOLOG probes in nine different habitats for over three months to demonstrate the applicability of the monitoring system. In the laboratory, EDAPHOLOG detected 95.6% of individuals; even the smallest morphotype (Oribatida, body size (mean±SE): 0.58±0.04 mm) were detected in 87.5% of cases. For body length estimation we established a quadratic relationship between the estimated and measured body lengths, however, the R2 of the quadratic model was only 0.32. By comparing the three different sampling methods (EDAPHOLOG, pitfall traps and soil extraction), we concluded that EDAPHOLOG traps better select for soil microarthropods compared to classical pitfall traps, since the latter ones caught also many other arthropod species. Furthermore, the EDAPHOLOG traps caught more epigeic microarthropods and almost the same number of soil-dwelling euedaphic microarthropods as the numbers collected by soil extraction. During the three month-long field test the total numbers of detected and captured individuals agreed very well, although the device tended to overestimate the number probably due to counting also some soil particles falling into the probe. This trend was the same regardless of the total number caught. Surface-dwelling epigeic and litter-dwelling hemiedaphic microarthropods dominated the samples although soil-dwelling euedaphic microarthropods were also caught. EDAPHOLOG is a novel device that consumes little power, rugged enough to operate in the field for extended periods of time, and can be remotely controlled. It detects surface- and soil-dwelling microarthropods real-time, and with high accuracy, however, it is less accurate to estimate body size. The system is especially suitable in field research focusing on temporal activity of microarthropods. Because it is non-invasive, studies requiring long term monitoring, such as soil remediation or ecosystem restoration projects, will also find EDAPHOLOG useful. This article is protected by copyright. All rights reserved.

Shelter, clothing, and fuel: Often overlooked links between soils, ecosystem services, and human health

There are clear connections between ecosystem services (ES) and human health, as well as between soils and human health. However, studies to date have not investigated links between soil ES and human health. Viewing the relationship between soils and human health through the ES lens reveals that soil ES such as the provisioning of shelter, clothing, and fuel have been overlooked in the soil and human health literature. Shelter is important to human health because it provides protection against inclement weather, temperature extremes, and other potential threats. Clothing provides a more consistent micro-environment around the skin and also provides protection from ultraviolet radiation and some parasites. Fuel allows us to warm shelters, providing refuge from cold temperatures, and cook food, which reduces disease. The materials supplied by soils in support of these functions are often done so in a more environmentally responsible way than is the case with many modern building and clothing materials or with fossil fuels. However, it is important to realize that sustainable management practices are critical in order to achieve environmentally responsible production of these products. Future studies need to investigate the links between these overlooked soil ES and human health.

An Opto-Electronic Sensor for Detecting Soil Microarthropods and Estimating Their Size in Field Conditions

Methods to estimate density of soil-dwelling arthropods efficiently, accurately and continuously are critical for investigating soil biological activity and evaluating soil management practices. Soil-dwelling arthropods are currently monitored manually. This method is invasive, and time- and labor-consuming. Here we describe an infrared opto-electronic sensor for detection of soil microarthropods in the size range of 0.4–10 mm. The sensor is built in a novel microarthropod trap designed for field conditions. It allows automated, on-line, in situ detection and body length estimation of soil microarthropods. In the opto-electronic sensor the light source is an infrared LED. Two plano-convex optical lenses are placed along the virtual optical axis. One lens on the receiver side is placed between the observation space at 0.5–1 times its focal length from the sensor, and another emitter side lens is placed between the observation space and the light source in the same way. This paper describes the setup and operating mechanism of the sensor and the control unit, and through basic tests it demonstrates its potential in automated detection of soil microarthropods. The sensor may be used for monitoring activities, especially for remote observation activities in soil and insect ecology or pest control.

THE EFFECT OF MULCHING ON THE ABUNDANCE AND DIVERSITY OF GROUND BEETLE ASSEMBLAGES IN TWO HUNGARIAN POTATO FIELDS

The benefits of mulching in potato ( Solanum tuberosum L.) production are manifold, such as it provides shelters for natural enemies of pests. The aim of our study was to detect the effect of two organic mulch types on the abundance, diversity and species composition of carabid beetles. Our potato plots were located in two sites with similar habitats including similar soil characteristics. Each plot was treated with hay and leaf litter mulch (hay, leaf, control) with 4 replications at each site. It resulted in 24 samples in each study site annually. Carabid beetles were collected by using pitfall traps in between 2011-2013. We found that due to mulching a larger and more diverse carabid population occurred on potato plots. Both mulching types increased the total number of carabids captured having a 17% higher abundance on hay mulched plots and 14% higher abundance on leaf litter mulched plots. According to the results 28 % of the collected species was found only on mulched plots, whereas only 13 % of the captured species were found only on unmulched areas. For some of the species, especially for Brachinus crepitans (L.), the number of individuals was significantly higher on mulched plots. The two different mulching materials had very similar effects on assemblages of carabid species. The species composition of ground beetles was considerably affected by the two locations, and to a lesser extent by the different time periods. While the dominant species of Budaors was B. crepitans, the most abbundant carabid beetle at Hidegkut belonged to genus Harpalus. Neither hay nor leaf litter were able to constantly increase the biodiversity of the carabid assemblages on potato plots, because the effect of the two years overwrote the between-treatment effects on carabid diversity. The positive effect of organic mulching on carabid diversity however, was found significant in both years of 2011 and 2012.