Gap analysis revealed a moderate efficiency of protected areas for the conservation of the endangered noble crayfish in Croatia

The noble crayfish is a native European freshwater species, endangered due to the strong anthropogenic influence on its habitats, climate change, and invasive crayfish species. In the present study, we aimed to assess the effectiveness of nationally designated protected areas and the pan-European Natura 2000 network in representing and maintaining over time the noble crayfish diversity using a comprehensive species occurrence dataset. Overall, our gap analysis indicated moderate efficiency of the existing protected areas in covering the noble crayfish diversity. Overlapping the distribution map of the noble crayfish with the map of protected areas revealed that protected areas encompass 50% of recorded populations. This study can serve as an evaluation of the protected areas in conservation of this key freshwater crayfish species

Značajke morfoloških obilježja biljaka i njihova uloga u postavljanju gnijezda trstenjaka mlakara (Acrocephalus palustris)

The Marsh Warbler (Acrocephalus palustris) nests in the plant communities of indigenous European species such as: Urtica dioica, Filipendula ulmaria, F. vulgaris and Phragmites communis. The biotopes that are colonized in Central Europe by the nettle (Urtica dioica) are covered with neophytes in Croatia (Solidago gigantea, S. canadensis, Helianthus tuberosus, Artemisia verlotiorum, etc.). The aim of this study was to establish to what extent these new plant species are appropriate for the settlement of the Acrocephalus palustris. The importance and role of plant species and the way the Marsh Warbler constructs its nest in vegetation structures with different shares of neophyta were studied. In the laboratory, the morphological features of plants relevant to nest building were measured.Trstenjak mlakar (Acrocephalus palustris) je u Europi tipična gnjezdarica autohtonih biljnih sastojina koju čine vrste Urtica dioica, Filipendula ulmaria, F. vulgaris, Phragmites communis i dr. U vegetaciji europskih riječnih obalnih staništa dominira kopriva, Urtica dioica, dok u Hrvatskoj iste tipove staništa nastanjuju uglavnom neofiti Solidago gigantea, S. canadensis, Helianthus tuberosus, Artemisia verlotiorum i dr. Cilj ovog priloga je prikazati kako neofitske sastojine i odabrana morfološka obilježja pojedinih biljnih vrsta utječu na odabir gnijezdilišta i postavljanje gnijezda trstenjaka mlakara u četiri kontinentalna područja Hrvatske

Money Kills Native Ecosystems: European Crayfish as an Example

Native European crayfish conservation was triggered by invasion of crayfish plague disease agent, Aphanomyces astaci, starting 1860s in Northern Italy. Resulting crayfish plague epidemics quickly spread over Continental Europe, then to Finland, Sweden and finally, after running amok around Europe, A. astaci was discovered also in Iberian Peninsula, Norway, Ireland, and United Kingdom in 1970s and 1980s. By that time significant proportion of native crayfish stocks had been lost, and while crayfish plague epidemics were still recorded, also industrialization and waterways construction were causing damage to remaining native crayfish stocks. While alien crayfish introductions, at least Faxonius limosus, already gave rise to first wave of crayfish plague epidemics in late 19th century, later in 1960s it was decided that introductions of alien Pacifastacus leniusculus should be initiated to replace native European crayfish populations. Decisions were based on presumed advantages for fishery, suitable habitat requirements and supposed immunity against A. astaci. Furthermore, conservation of native European crayfish species was sidelined and focus shifted toward alien crayfish stocking routine and consumption. Alien crayfish species introductions resulted in repeated waves of crayfish plague epidemics among remaining native crayfish stocks. It was soon discovered that alien crayfish of North American origin were, as suspected, permanent reservoirs for A. astaci, that some of those alien species were losing their resistance against selected strains of A. astaci and struggled in European aquatic ecosystems. In this article, we introduce numerous motives behind grand mistake of introducing alien crayfish species to Europe and then promoting their stocks instead of focusing on conservation of native crayfish species. We outline how false economical, biological and ecologic assumptions were used to justify a hasty introduction of alien crayfish, which has further devastated native crayfish and also permanently changed European aquatic ecosystems, both with disastrous consequences. Lesson to be learnt is that science-based warnings about alien species damage to native ecosystems and native crayfish must be taken with utmost caution. Protection of native European crayfish should be core issue, not commercial activities. Finally, we summarize main threats and actions needed to protect remaining native freshwater crayfish fauna in Europe

Koliko dobro postojeća Natura 2000 mreža štiti ugroženog potočnog raka u Hrvatskoj?

The stone crayfish Austropotamobius torrentium (Schrank, 1803) is a threatened native European freshwater crayfish species for which Natura 2000 network represents the most important conservation effort at the European level. In Croatia, there are altogether 25 Natura 2000 sites defined specifically for this species. In the present study, we aimed to assess the effectiveness of Natura 2000 sites in preserving stone crayfish diversity through gap analysis, a GIS-based approach that overlays species distribution data on a map of designated Natura 2000 sites. Our results showed that the existing Natura 2000 network in Croatia encompasses most of the areas with a high diversity of A. torrentium; currently designated sites harbour 73.3% of recorded A. torrentium populations. Future conservation planning efforts, and possible expansion of Natura 2000, should be focused on newly discovered A. torrentium populations that present divergent evolutionary lineages.Potočni rak Austropotamobius torrentium (Schrank, 1803) je ugrožena autohtona europska vrsta slatkovodnog raka porodice Astacidae za kojeg mreža Natura 2000 predstavlja najvažniju inicijativu u konzervaciji na europskoj razini. U Hrvatskoj uključuje 25 područja određenih posebno za ovu vrstu. Cilj ovog istraživanja je bio procijeniti učinkovitost Natura 2000 područja u očuvanju raznolikosti potočnog raka kroz gap analizu koja se temelji na preklapanju karata rasprostranjenosti ove vrste i Natura 2000 određenih područja korištenjem GIS programskog paketa. Rezultati su pokazali da postojeća mreža Natura 2000 u Hrvatskoj obuhvaća 73,3% populacija potočnog raka te uključuje i područja njegove najveće raznolikosti. Pri izradi budućih planova konzervacije ove vrste i mogućih proširenja Natura 2000 područja posebnu pažnju treba obratiti na novootkrivene populacije koje ujedno predstavljaju evolucijski divergentne linije

The value of protected areas ranger service personnel for biodiversity monitoring: case study in Paklenica National Park (Croatia)

To preserve the long-term survival of habitats and wildlife, it is necessary to monitor their status. In protected areas, that is, biodiversity centres, rangers have excellent knowledge of specific locations and they spend a large amount of time in the field. But since rangers are not required to have a university degree, the question is whether they can be an added value in baseline survey monitoring. To investigate this issue, a case study was conducted in the Paklenica National Park (Paklenica NP), Croatia, using camera trapping survey between 2011 and 2016 at 22 camera sites. The aims of this survey were (1) to collect baseline data of mammalian diversity, (2) to analyse the regulatory effect of top predators on the trophic pyramid through top–down effects and (3) to estimate the data gathered by ranger service from the Paklenica NP. Data gathered through this study represents the first peer-reviewed list of medium- to large-sized mammals for Paklenica NP, as up till now, there is no peer-reviewed published paper of Paklenica NP mammalian diversity. Results showed that the recorded top predator–mesopredator–prey ratios were concordant with the trophic pyramid hypothesis. Also, as it was expected according to the literature, species richness indices were higher when top predators were present. On analysing the costs for conducting camera trapping survey by external and internal services, a significant difference was observed. Internal rangers’ cost was nine times lower than the external service cost. Future research run by rangers needs to be conducted in way to capture all mammalian biodiversity. Therefore, we propose camera trapping methodology for rangers in the protected areas since this may be an invaluable tool for biodiversity monitoring

Application of the geometric morphometrics approach in the discrimination of morphological traits between brown trout lineages in the Danube Basin of Croatia

Brown trout is a salmonid fish with a natural range extending throughout western Eurasia and North Africa. Due to its commercial value, it has also been introduced worldwide. In continental Croatia, introduced trout of the Atlantic lineage hybridizes with native trout of the Danubian lineage, threatening the native genetic diversity. The geometric morphometrics approach was used in this study to analyse changes in shape between native trout, introduced trout and their hybrids, classified a priori by molecular phylogenetic analyses. A total of 19 landmarks and semi-landmarks were used to capture the shape of 92 trout individuals belonging to two lineages and their hybrids. Canonical variate analysis and discriminant function analysis were used to analyse and describe shape variation. A significant difference was found between the shape of the Atlantic lineage trout and both Danubian lineage trout and hybrids, with the most prominent differences in body depth, head length and eye size. No statistically significant shape differences were observed between Danubian lineage trout and the hybrids. The observed significant differences in shape could be the result of genetic diversity or trout phenotypic plasticity. Further studies are needed to clarify the origin of this variation in shape

Invasion biology in non-free-living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in crayfish commensals (Ostracoda, Entocytheridae)

In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum-Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum-Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This approach can also be implemented in other systems where the target species is closely interacting with other taxa