Continent-wide loss of traditionally managed humid meadows is raising concern for associated butterfly specialists across Europe. However, not all species associated with this biotope are threatened, and the Lesser Marbled Fritillary (Brenthis ino) has even spread locally. We employed mark-recapture and transect walks to study its population structure and patterns of landscape occupancy in a hilly region of western Bohemia, Central Europe, to determine which life history or demography traits might be responsible for its success. A population studied by mark-recapture harboured more than 1000 individuals and was interconnected with other populations. This was further supported by a fit of the inverse power function to dispersal data. Observations of adult behaviour revealed a broad host plant range: at least three species of plants were used by the single population. On a landscape scale, the butterfly exhibited an aggregated distribution matching its host plants. It was associated with the distribution of characteristic plants and butterflies of semi-natural humid meadows, but its frequency exceeded those of other humid grasslands specialists. The relatively broad host range coupled with varying biotope requirements of individual host plant species results in a wide biotope range for the butterfly, explaining its persistence in fragmented Central European landscapes.
The Marsh fritillary (Euphydryas aurinia) (Lepidoptera: Nymphalidae) has declined across Europe, including the Czech Republic. Current conservation strategies rely on prevention of habitat loss and degradation, and increase in habitat quality and connectivity via promoting traditional grassland management. The population structure and adult demography parameters of a single population was investigated for eight years (single system), and of all the known Czech populations (multiple populations) for a single year, using mark-recapture. There was substantial variation in the patterns of adult demography, both among years in the single system and among the multiple populations in a single year. In the single system, the date of the first flight of an adult varied by 18 days over the 8 years and total annual numbers varied with a coefficient of variation of 0.40 (females fluctuating more than males). The average density was ca 80 adults/ha. The population size displayed density-dependence, i.e. decreased following years with high adult numbers, with an equilibrium density of 90 individuals/ha. The average density of the multiple populations was ca 120 individuals/ha. The estimated total population for the Czech Republic was 25,000 individuals (17,000 males / 8,000 females) in 2007, which does not indicate an imminent threat of extinction. The regional persistence of E. aurinia is likely to depend on re-colonisation of temporarily vacant sites by dispersing individuals, facilitated by local shifts in adult flight phenology to that better adapted to local conditions. and Kamil Zimmermann, Pavla Blazkova, Oldrich Cizek, Zdenek Fric, Vladimir Hula, Pavel Kepka, David Novotny, Irena Slamova, Martin Konvicka.
We studied a population of the regionally endangered marsh fritillary butterfly Euphydryas aurinia inhabiting a system of loosely connected dry calcareous grasslands in sub-Mediterranean Slovenia. Our goal was to set the basis for a long-term monitoring of this butterfly in four meadows using mark-release-recapture (MRR). We determined its demographic parameters, dispersal, behaviour and utilization of nectar plants in different quality patches. Total population size was estimated to be approximately 347 males (95% confidence interval: 262-432) and 326 females (95% confidence interval: 250-402), with an unbiased sex ratio. The average lifespans were 6.3 and 8.6 days, respectively. Daily population sizes followed a parabola with marked protandry. Both sexes were relatively highly mobile with both occasionally moving over half a kilometre. The spatial distribution of animals seemed to be associated with patch size, host plant densities and nectar sources, resulting in much higher population densities in the largest patch. Adult behaviour differed between the sexes, with females resting more and flying less than males. Behaviour also changed during daytime and with the progression of the season. Adults were confirmed to be opportunistic feeders, since as many as ten nectar sources were detected. We conclude that demographic parameters differ greatly among regions and habitats, thus conservation aims should be planned accordingly. Although the population studied is apparently in good condition, there are threats that may hamper the long-term persistence of the species in this area: succession, intensification of mowing and overgrazing., Jure Jugovic, Costanza Uboni, Sara Zupan, Martina Lužnik., and Obsahuje bibliografii
Which factors influence the occurrence, population size and density of species in fragmented habitat patches are key questions in population and conservation ecology. Metapopulation theory predicts that larger and less isolated habitat patches should positively influence species occurrence and population size. However, recent studies have shown that habitat quality, human activity and permeability of the landscape surrounding habitat patches may be also important. In this paper we test the relative effects of habitat patch characteristics, human settlement and landscape permeability on the occurrence, local population size and density of the Chalk-hill Blue Polyommatus coridon a charismatic butterfly inhabiting calcareous grasslands in a fragmented landscape in southern Poland. Patch occupancy rate (corrected for the butterfly detection probability) was 0.45. Habitat patch area, proximity of human settlement and cover of larval food plants positively affected occurrence of the Chalk-hill Blue. Local population size of the Chalk-hill Blue was positively affected by patch area and proximity of human settlement, and negatively by patch isolation. Local density was higher in patches located close to human settlement. Our study is one of the few showing a positive effect of human settlement on a grassland specialist butterfly although the mechanism hidden behind this phenomenon is unknown and requires further examination. In order to maintain local populations of the Chalk-hill Blue in southern Poland, conservation action should be focused on large, closely connected calcareous grasslands. Moreover, extensive management of this habitat should be maintained by local inhabitants who are better placed to undertake such work. and Zuzanna M. ROSIN, Piotr SKÓRKA, Magdalena LENDA, Dawid MORON, Tim H. SPARKS, Piotr TRYJANOWSKI.
Altogether 701 adult barbel, Barbus barbus were captured by electrofishing and individually tagged to study their local displacement and movements in a stretch of the River Jihlava (Czech Republic). A total of 149 fish were recaptured and 105 of them (70.47 %) were considered as ”resident” because they were always recaptured in the same, relatively restricted (250 - 780 m) stream section, which always contained a pool and was demarcated naturally by riffles on both edges. The remaining 44 recaptured specimens (29.53 %) belonged to the “mobile” part of population, their movements encompassing two (or exceptionally more) adjacent stream sections and at maximum a distance of 1680 m downstream or 2020 m upstream. The proportion of mobile barbel, relatively low in smaller and middle size classes, increased in the largest size classes (451–550 mm of SL). A rather limited extent of movements also suggests a relatively small area of home range in the studied stretch, which nevertheless provides satisfactory resources and favourable conditions required by barbel over their entire life cycle. The extent of movements and corresponding proportion of mobile fish appear to be increasing with diminishing habitat patchiness. In the stretch of River Jihlava studied, with a rich patchy heterogenous habitat and well developed riffle-pool-raceway structure, each section (pool) can be considered as a more or less isolated spatial unit containing its own, and in a certain degree, isolated component of a metapopulation.
Chequered blue butterfly, Scolitantides orion (Lepidoptera: Lycaenidae) has severely declined in many parts of Europe and is currently red-listed in many countries. We studied the population structure and turnover of the species in a lake-island system in a National Park in eastern Finland over a three-year period. The incidence of the chequered blue on the suitable islands (n = 41) and habitat patches (n = 123) was high: an average of 82% of the islands and patches were occupied over the three year period. At the island scale, the annual population turnover rate was 17%, with an extinction and colonization rate of 7% and 10%, respectively. At the patch scale, the annual population turnover was 16%, with 7% extinction and 9% colonization rate. Islands that were occupied over the three year period had a larger area of suitable habitat than islands in which turnover events were observed. At the patch scale, turnover events were observed in small and poorly connected patches. Patchy occurrence of the host plant and observed extinction-colonization dynamics suggest that the chequered blue population confirms a metapopulation structure. Although the local populations are small, the observed high patch occupancy and balanced population turnover indicates that the metapopulation is not in immediate risk of extinction.
Many species of chironomids undergo their immature development in habitats that rapidly change in suitability, such as rain pools, phytotelmata, freshly filled ponds or soil layers that seasonally dry out. Strategies for the utilization of these habitats can be divided into two groups: i) physiological or behavioral adaptations of larvae, which enable them to survive unsuitable conditions (in situ resistance) or ii) repeated recolonization of temporarily suitable habitats. In situ resistance, includes desiccation or frost resistance, often in combination with cocoon building and migration of larvae into the sediment. Generally, the species that use the recolonization strategy tend to be better at migration and have a higher fertility and shorter development. Recolonization may include only temporary habitats or temporary habitats and some more stable habitats as well.
In 1995-1997, we studied the factors which may influence the ground "activity density" of Carabidae using pitfall traps placed in winter wheat, winter rape and pea stands (1995 only) grown within a 1 km2 area with uniform physical conditions. The traps were placed in plots of bare ground established within the crops and under surrounding intact plant stands. The communities were similar between crops within years (Pearson's correlation coefficient r = 0.60 - 0.81), and between years within crops (r = 0.89 - 0.91), except for the poor winter rape stand in 1997. Factors influencing carabid "activity density" were: (i) Density of crop stand. The carabids preferred crop-shaded ground as long as crop density was low or medium but moved to bare ground plots when crop density became high. Under moderate crop density the preference differed between beetle species, most of which preferred crop-shaded ground while a few ones preferred bare ground. Carabid preferences were probably determined by microclimatic differences caused by presence and density of crop cover. (ii) Presence of seeds dropped on the ground. In rape stands, presence of crop and weed seeds increased the "activity density" of seed predators (species of genera Amara, Harpalus, Ophonus and Pseudoophonus). Scattering of rape seeds significantly increased local activity density of Harpalus affinis and H. distinguendus in the wheat stand. (iii) Presence of aphids. Activity density of Bembidion lampros and Trechus quadristriatus and between-year variation in pooled abundance of the five species recognised as aphid predators was associated with variation in aphid abundance.