Environmental factors and intrinsic processes affecting habitat use of European ground squirrels (Spermophilus citellus): putting science into conservation practice

Disszertációmban megismertetek néhány fontos külső (környezeti) vagy belső folyamatot, amelyek meghatározóak a közönséges ürge (Spermophilus citellus; továbbiakban ürge) vagy Gunnison préri kutya (Cynomys gunnisoni; továbbiakban préri kutya) élőhelyhasználatában. Az ürge előnyben részesíti a friss sovány csenkeszt (Festuca pseudovina) a fészeképítésben, a magasabb mértékű szigetelőképessége miatt. Eredményeim azt mutatják, hogy az ürgék nem nélkülözhetik a rövid füves pusztákon karakterisztikus szárazságtűrő csenkeszt, mint fészek alapanyagot. Feltételezhető, hogy a populációk térbeli kiterjedése akkor növekszik, illetve azok hosszú távú fennmaradása akkor biztosított, amennyiben az élőhely karakterisztikus faja a csenkesz. A préri kutyák a kupacokat használják ragadozó elkerülő megfigyelésre, és a megfigyelés napi aránya a növényzet magasságának növekedésével emelkedik. A kolónia peremén élő egyedek megfigyelés mértéke magasabb, és az a kolóniához képest kifelé irányuló. A kupacok térfogatának mérésére kidolgozott számítási eljárásunkkal jól becsülhető a járatok térfogata. Segítségével a mesterséges vagy új járatok méretének változása jobban nyomon követhető. A préri kutyák által “megművelt” talajmennyiség (min. 6,5 – 16,6 m3) összhangban van az ökoszisztéma mérnök fajokról alkotott meghatározással. Az ürge áttelepítések során azt tapasztaltuk, hogy az új élőhelyen való megtelepedést elősegíti, ha az elengedési időpontja a reggeli aktivitási csúcshoz illeszkedik, továbbá a mesterséges járatok elzárása megakadályozza az áttelepített állatok pánikszerű menekülését, így hozzásegít a terület kolonizációjához. A ferde mesterséges lyukak közepesen magas füves élőhellyel párosítva (18 cm ± 12 SD) kedvezően hatnak az áttelepítési sikerre. A magyarországi, ausztriai, és romániai ürgepopulációk genetikai diverzitása viszonylag magasnak mondható, mint a genetikailag elszegényedett cseh ürge populációké. Azonban a Sciuridae családba tartozó más fajok magasabb genetikai változatosságot mutatnak, mint akár a hazaiak akár az ausztriaiak. Az eredményeink alapján elmondható, hogy az ürgék érzékenyek a környezeti tényezőkben bekövetkező változásokra, ezért a populációk mérete erőteljesebben ingadozik térben és időben egyaránt. Ez az ökológiai érzékenység a „scramble competition polygyny” szaporodási rendszerrel párosulva sokkal nagyobb veszélyt rejtenek magukban a faj fennmaradása szempontjából, mint az áttelepítésekben rejlő genetikai kockázatok. Ezt támasztja alá az ürge populációk eltűnése, elszigetelődése az ürge elterjedési területén

IMPORTANCE OF BURROW-ENTRANCE MOUNDS OF GUNNISON'S PRAIRIE DOGS (CYNOMYS GUNNISONI) FOR VIGILANCE AND MIXING OF SOIL

Aboveground mounds and underground burrows are multifunctional and influence behavior and habitat of Gunnison's 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 m(3) of air in the burrow make the geomorphic effect of prairie dogs potentially significant

The role of landscape history in determining allelic richness of European ground squirrels (Spermophilus citellus) in Central Europe

Genetic diversity is of paramount importance for individual fitness and evolutionary potential of populations. For conservation planning it is crucial to know how genetically diverse a species is and what factors may explain variation of genetic diversity among populations. Our aim was to evaluate the effects of landscape history, ecological isolation, and local population size on allelic richness of local populations in European ground squirrels (Spermophiluscitellus). We genotyped 144 individuals from nine local populations collected in two neighbouring regions with decades of different landscape history. We assessed allelic richness, ecological isolation and local population size by eleven polymorphic microsatellites, the isolation index of Rodríguez and Delibes,and standardised counts of burrows openings, respectively. Statistical models indicated a strong effect of landscape history on allelic richness of local populations. Ecological isolation of local populations apparently played only a marginal role, and local population size was an unimportant factor. Our modelling results highlight the dominant role of landscape history for the genetic diversity of S. citellus. The strong landscape history effect encountered presently includes a different region-specific socio-economic development due to distinct agricultural systems in the two regions, especially after World War II. Levels of ecological isolation of local populations have diverged in an extent too small to explain variation of local allelic richness. The lack of significant effect of local population size suggests that census sizes of the populations studied are all not critically low. Moreover,census and estimated effective population sizes were not closely related. Establishing corridors or translocating S. citellus in the species’ historical range should be encouraged to promote gene flow between local populations and counteract the loss of genetic diversity by drift, provided that no conflicting factors (ecological, epidemiological, etc.) exist

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 Budaörs was B. crepitans, the most abbundant carabid beetle at Hidegkút 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

Morning release into artificial burrows with retention caps facilitates success of European ground squirrel (Spermophilus citellus) translocations

Relocating ground squirrels within their natural distribution range is a popular tool in wildlife management in Central– Eastern Europe. Nevertheless, wildlife management lacks both a carefully developed and tested translocation guide and methods. We evaluated conditions of release method (time of release and retention of animals) that affect short-term settlement of translocated ground squirrels in the central region of Hungary. In a field experiment, we translocated 117 individuals from an international airport to a protected site in 2000. We found that release time should precede the animals' natural, daily activity peak. The use of retention caps combined with artificial burrows instead of complex acclimation cages works successfully to prevent animals from dispersing from the release site