Vladimír Vrabec

Selection on dispersal in isolated butterfly metapopulations

In most metapopulation models dispersal is assumed to be a fixed species-specific trait, but in reality dispersal abilities are highly sensitive to various selective pressures. Strict isolation of a metapopulation, which precludes any influx of immigrants (and their genes) from outside and makes it impossible for emigrants to reach other localities with suitable habitat, thus reducing fitness benefits of long-distance dispersal to zero, may be expected to impose strong selection against dispersal. We tested the above prediction by comparing dispersal parameters derived with the Virtual Migration model for isolated and non-isolated metapopulations of two species of large blue Maculinea (= Phengaris) butterflies, surveyed with intensive mark-recapture. Mortality during dispersal was found to be twice (in M. teleius) to five times higher (in M. arion) in isolated metapopulations. Isolation also resulted in significantly reduced dispersal distances in isolated metapopulations, with the effect being particularly strong in M. arion females. Apart from its evolutionary and ecological consequences, dispersal depression in isolated butterfly metapopulations implied by our results has serious conservation implications. It provides a clear argument against using parameter values obtained in a different environmental setting in modelling applications, e.g., Population Viability Analyses or environmental impact assessment. Furthermore, it underlines the importance of establishing well-connected networks of suitable habitats prior to species release in areas where reintroductions are planned.

Land management impacts on European butterflies of conservation concern: a review

Recent land use changes, namely the intensification of agriculture and forestry as well as the abandonment of traditional grassland management methods, have resulted in the decline of butterfly diversity in Europe. Appropriate management of butterfly habitats is thus required in order to reverse this negative trend. The aim of our study was to review the available literary information concerning the effects of various types of management on European butterflies of conservation concern, and to provide practical recommendations for the management of butterfly habitats. Since vegetation succession is a major threat to butterfly populations, there is a need for activities to suppress this process. Extensive grazing and rotational mowing, which imitate the traditional way of meadow use, appear to be the most suitable management in this respect. Both grazing and mowing should optimally be of low intensity and follow a mosaic design, with different land fragments being successively used at different times. Habitat disturbance through trampling, either associated with grazing or various sporting activities (hiking, biking, horse riding), or through occasional small-area burning, also prove to be beneficial for many butterflies. In the case of woodland species, maintaining open habitats within forests (glades, clearings, wide road verges) and thinning forest stands is recommended. Among the unfavourable management activities identified, the most harmful are afforestation of open lands and drainage works. Therefore, such activities must be stopped at butterfly sites in order to ensure the effective conservation of species of conservation concern.

Adult longevity and its relationship with conservation status in European butterflies

Many European butterfly species are currently experiencing serious declines, and may be threatened with extinction. Nevertheless, due to limited knowledge on the species biology and ecology, detailed assessments of endangerment level are not possible, and instead identifying species of conservation concern has to rely on proxies. Earlier studies suggested several characteristics, including host plant specificity, overwintering stage, patch size requirements or mobility, as potentially useful indicators of butterfly species vulnerability, but the usefulness of adult longevity in this respect has not been considered so far. Based on the information gathered through an extensive literature search we investigated the relationship between adult life span, flight period length or the temporal fragmentation index calculated as the ratio of the two parameters, and conservation status of European butterflies. We found that the species classified in one of the IUCN conservation concern categories (i.e. Endangered, Near Threatened, or Vulnerable) lived shorter as adults and were characterised by higher values of the temporal fragmentation index, while there was no particular pattern concerning flight period length. We believe that the apparent effects detected reflect the fact that shorter adult life span, and thus increased temporal fragmentation, in combination with protandry, i.e. earlier emergence of males, decrease individual chances of finding mating partners. Such a situation leads to lower effective population size and reduced viability, especially in the case of small populations. All concerned, the investigated parameters reflecting adult longevity may serve as ‘early warning’ indicators, helping to flag-up butterfly species possibly at risk.

Aquarium molluscs as a case study in risk assessment of incidental freshwater fauna

Because biological invasions may cause loss of biodiversity, accurate predictions are necessary for implementing effective restrictions aimed at specific high-risk taxa. The majority of freshwater macroinvertebrate invaders are molluscs and crustaceans. The pet trade has been considered one of the main pathways for new introductions of such species. Risk assessment is usually focused on traded ornamental species whereas, despite their potential importance, incidental “hitchhiking” molluscs are usually given only minimal consideration. We surveyed the Czech Republic, which is one of the leading markets for aquarium species in the European Union (EU), and found 41 freshwater mollusc species (25 ornamental gastropods, 6 ornamental clams, and 10 “hitchhiking” gastropods) representing 13 families. We extrapolated data from the Czech Republic and, using Climatch v. 1.0, matched the climate in each species’ native range to the entire territory of the EU. We also assessed the risk associated with each species by FI-ISK. “Hitchhiking” gastropods were found to be significantly more hazardous and with higher potential to become established within the EU than were ornamental gastropods and bivalves. Many “hitchhikers” may be easily overlooked due to their small size and cryptic coloration or shape. Thus, they easily can be accidentally imported in association with aquarium plants. Therefore, we recommend here to disinfect imported ornamental plants to eradicate these unwanted faunal assemblages.

Potential pest transfer mediated by international ornamental plant trade

In recent years, the keeping of ornamental freshwater animals and plants in garden ponds has been growing in popularity. Water hyacinth (Eichhornia crassipes) is one of the preferred macrophytes seasonally imported mainly from South-eastern Asia throughout the world. This constitutes a secondary introduction inasmuch as the species is native to South America. Although many assemblages of aquatic invertebrates have been described as associated with this plant in the wild, there has been no research focused on their potential introduction via the international plant trade. We examined 216 specimens of water hyacinths imported for ornamental purposes from Indonesia into the Czech Republic. Numerous meio- and macroinvertebrates belonging to at least 39 species were captured. On the total number of individuals, the highest prevalence was of Tubulinea and Rotifera. Most of these were still alive and vital, including a caterpillar of the Indo–Australian invasive moth Spodoptera litura. Water hyacinths are usually placed into outdoor ponds immediately after import, which facilitates the release of non-target alien species. The present paper aims to draw attention to “hitchhikers” associated with the ornamental trade.

Which Wild Aardvarks Are Most Suitable for Outdoor Enclosures in Zoological Gardens in the European Union

ABSTRACT The aardvark is popular in many zoological gardens in the European Union. These creatures are nocturnal, and aardvarks in the wild are known to walk distances of 4 km to 7 km per night. Despite what is known about their biology, most aardvarks are kept in zoological gardens in indoor enclosures with little space for movement. This lack of space leads to a tendency toward obesity and compromised welfare. With their wide distribution in Sub-Saharan Africa, aardvarks are perceived as thermophilic nonhuman animals. Nevertheless, some records suggest they may be able to adapt to colder climates and can be active outside their burrows when temperatures fall to 2°C. These findings suggest there may be a wild African population that is suitable for partial outdoor keeping under European climatic conditions. Therefore, a climate match was computed between the source area with aardvark occurrence and a target area of the European Union. Data revealed that the Free State, a South African province, was the area with the best climate similarity, and aardvarks from this area are recommended as suitable for the aforementioned purpose.

Long-term monitoring of Phengaris (Lepidoptera: Lycaenidae) butterflies in the Přelouč surroundings (Czech Republic): is the waterway construction a serious threat?

The monitoring of sympatrically occurring Phengaris teleius and P. nausithous metapopulations in the surroundings of Přelouč, Czech Republic, was launched over a decade ago in connection with the planned waterway construction on the Elbe river. The mark-recapture surveys were initially restricted to 10 habitat patches on the right river bank, but in 2010 three new patches were discovered on the opposite bank. We use the monitoring results for 2011–2015 to assess how the discovery of additional populations alters the impact evaluation of the prospective construction. The overall abundance of P. teleius in the recently discovered populations was about twice as high as on the right bank (ca. 2,800 vs. 1,400 adults on average), while the numbers of P. nausithous on both banks proved to be balanced (at ca. 600 adults on average). Furthermore, we confirmed a substantial exchange of butterflies between population representing both banks, which indicates a well-integrated metapopulation in both species. Since the waterway would partly destroy the two largest populations on the right bank, the potential loss due to its construction is estimated at 40.1–64.3% P. teleius individuals and 20.2–47.4% P. nausithous individuals occurring there. Nevertheless, concerning the entire metapopulation, the predicted decline is considerably smaller, reaching 13.9–25.7% in P. teleius and 8.5–20.0% in P. nausithous. Consequently, a long-term survival of the species is likely even in the case of the waterway construction, as long as appropriate management is applied on the unaffected habitat patches.

Effect of sex on the nutritional value of house cricket, Acheta domestica L.

Since January 2018, insects have been recognised as novel foods in the EU, but their nutritional value varies, and factors affecting their nutritional composition have been debated. We investigated the effect of sex on the nutritional value and chemical composition of the house cricket (Acheta domestica L.). Both sexes were rich in protein and lipids. The proximate composition was partly influenced by sex; females contained a significantly higher amount of lipids (18.3-21.7 vs 12.9-16.1 g/100 g dry matter, p = 0.0001) and fewer proteins than males (61.2-64.9 vs 66.3-69.6 g/100 g dry matter, p = 0.0001). Males contained more chitin (p = 0.0015) and nitrogen chains (p = 0.0003) than females. Only the ash (p = 0.4314) and nitrogen-free extract (p = 0.4871) were uninfluenced by sex. Furthermore, nutrient quality expressed as essential amino acid (72.3-77.1), thrombogenicity (1.22-1.45), and atherogenicity indices (0.53-0.58) did not differ between sexes (p > 0.05).

Intensive Mowing Effect of One Patch on the Metapopulations of Two Phengaris Species

Abstract In the second half of the 20th century, change of land use in the name of intensive agriculture was one of the most important factors caused significant loss of butterfly diversity in Europe. Phengaris nausithous and Phengaris teleius belong among the flagship species associated with wet meadows and are directly threatened by the intensive agriculture practises or management abandonment. Due to their very specific lifecycle, they are closely linked to their habitats and appropriate mowing management on their patches is thus crucial for their survival. Our research took place in Dolní Labe, Děčín, Czech Republic, on 16 patches and has been performed using Mark-Release-Recapture since 2009. This paper will illustrate how intensive mowing management, applied on only one of the patches, which forms only 9.4% of total locality size, can influence the entire local Phengaris metapopulation. The selected patch was intentionally mowed in the middle of flight season annually for four years. Even though, no significant effect was identified after the first year of study, after the second and third seasons, there was evidence of population decline of both studied species.

Evaluation of Active Management Applied to Meadows with Phengaris Butterflies Occurrence

Abstract In recent decades, changes in meadows maintenance have reduced the populations of endangered butterfly species Phengaris nausithous (Bergsträsser, 1779) and P. teleius (Bergsträsser, 1779). Currently, meadows are either abandoned or intensively used. Unfortunately, both these managements are considered unfavourable for grassland butterfly species. In this study, the effect of suitable meadow management on population sizes of both the above mentioned Phengaris species was investigated. The experiment was performed at the locality Dolní Labe (Děčín, Czech Republic). The most suitable models, based on the lowest values of Akaike’s information criterion corrected for small sample sizes, were selected using MARK statistical software. The results were subsequently compared with data obtained from this locality prior to the management application. Unexpectedly, no significant positive effects were found. To reach the desirable status, suitable management practices should be applied for long-term. To verify the management effect on the population size, the meadows were divided into three groups: (i) application of favourable management, (ii) mowing in inappropriate term, (iii) without management. Based on the statistical evaluation, the management application proved to be the most favourable option for both studied butterflies species.