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21.
Maxime Taverne Anne‐Claire Fabre Nina King‐Gillies Maria Krajnovi Duje Lisi
i Louise Martin Leslie Michal Donat Petricioli Anamaria tambuk Zoran Tadi Chlo Vigliotti Beck A. Wehrle Anthony Herrel 《Ecology and evolution》2019,9(22):12408-12420
Access to resources is a dynamic and multicausal process that determines the success and survival of a population. It is therefore often challenging to disentangle the factors affecting ecological traits like diet. Insular habitats provide a good opportunity to study how variation in diet originates, in particular in populations of mesopredators such as lizards. Indeed, high levels of population density associated with low food abundance and low predation are selection pressures typically observed on islands. In the present study, the diet of eighteen insular populations of two closely related species of lacertid lizards (Podarcis sicula and Podarcis melisellensis) was assessed. Our results reveal that despite dietary variability among populations, diet taxonomic diversity is not impacted by island area. In contrast, however, diet disparity metrics, based on the variability in the physical (hardness) and behavioral (evasiveness) properties of ingested food items, are correlated with island size. These findings suggest that an increase in intraspecific competition for access to resources may induce shifts in functional components of the diet. Additionally, the two species differed in the relation between diet disparity and island area suggesting that different strategies exist to deal with low food abundance in these two species. Finally, sexual dimorphism in diet and head dimensions is not greater on smaller islands, in contrast to our predictions. 相似文献
22.
Ranka Rajković-Janje Sanja Bosnić Damir Rimac Tihomira Gojmerac 《European Journal of Wildlife Research》2008,54(3):525-528
From October 2002 till April 2003, 194 feces samples and 28 liver samples of red deer shot in the Republic of Croatia territory
were examined to determine the prevalence of Fascioloides magna in this game population. The majority of study samples were obtained from animals originating from the east part of Croatia,
and only a minor proportion from animals originating from the central and west parts and littoral of Croatia. F. magna eggs were detected in 67/194 (34.53%) feces samples and F. magna adults in 8/28 (28.57%) liver samples. The majority of invaded red deer originated from the east part of Croatia, Baranya
region, where F. magna eggs were found in 64/120 (53.33%) and F. magna adults in 8/15 (53.33%) animals. F. magna eggs were detected in only 3/74 (4.05%) animals originating from the other parts of Croatia. 相似文献
23.
The golden jackal (Canis aureus) is one of the less studied carnivores and research on its major histocompatibility complex (MHC) variability is just at its early stages. MHC genes encode cell-surface receptors that serve to bind and present antigens to T cells, which is essential to initiating specific immunological responses in vertebrates. In this paper we present for the first time patterns of genetic diversity and natural selection on MHC class II DLA-DRB1, DQA1 and DQB1 loci in the golden jackal using samples from two geographically distinct regions in Croatia and further compare them to the values found in its congener grey wolf (Canis lupus). Diversity of golden jackals at all three loci was markedly lower than that of grey wolves (allelic richness values were 4, 2 and 3 in jackal versus 11.9, 6.6 and 10.2 in wolves for DRB1, DQA1 and DQB1, respectively) and can be attributed to a genetic drift rather than to the lack of historical positive selection. The finding of high evolutionary distances (16.3% for DRB1 and 8.5% for DQB1) and a substantial number of codons predicted to be under the influence of positive selection (11 for DRB1 and 9 for DQB1) suggests that the investigated golden jackal population still contains considerable functional diversity necessary for the presentation of varied foreign peptides. In contrast to neutral genetic variation, our results suggest that the Dalmatian population has a higher MHC diversity than the Slavonian population, casting doubt on its supposed isolation and calling for a more extensive investigation of the MHC variability of southern Balkan jackal populations. 相似文献
24.
Scinderella scopuliformis nov. gen., nov. sp. is identified in the Anisian (Middle Triassic) reef limestones from the Belski dol quarry (Ivanš?ica Mt., NW Croatia). The new alga is characterised by claviform thallus, curved in the basal part, and very narrow central cavity. Thallus is often disintegrated into fragments. Laterals swell from a thin basal part, and have uniform (rarely slightly increasing) diameter along most of their length. Distally, they are flattened and probably touch each other, forming an irregular cortex. Laterals are arranged densely in close whorls and oblique to the longitudinal axis. Euspondyl arrangement is readily visible in the proximal part of the laterals, but distally, the arrangement seems more or less irregular, i.e. ruffled (Lat. scindere = ruffle, dishevel) and resembling a broom (Lat. scopulae = small broom; forma = form, shape). 相似文献
25.
In this paper we analyzed nutrient concentration in the channels of eastern Croatia and investigated whether certain plant
species and associations can be used as direct estimators of water quality. One hundred and twenty-two channel sites were
visited and water samples taken for laboratory analysis (pH and concentrations of sulfate, chloride, ammonium, nitrate, and
total phosphorus). At each site, macrophyte vegetation was recognized and its occurrence recorded. Three groups of analyses
were performed: (a) principal component analysis to describe habitat characteristics of the investigated channels, (b) stepwise
regression analysis to build estimation models for nutrient concentrations, and (c) geostatistical analysis including fitting
of variograms and interpolation of values over the whole area of interest. High values of water nutrients in the eastern Croatian
channels were reported (90% intervals): 5.3–29.4 for nitrates, 27.8–54.2 for sulfates, 0.1–0.4 for total P, and 0.18–0.34 mg l−1 for ammonium. Water nutrient concentrations can be successfully mapped over the channel network in eastern Croatia using
geostatistics (regression kriging). The nutrient concentration variables required log transformation prior to regression or
variogram analysis because their distributions were distinctly skewed towards lower values. Species were found to be a more
successful estimator of nutrient concentrations than plant associations. In all cases, species had a higher adjusted R-square value, ranging from 0.302 (ammonium) to 0.485 (sulfates). Additional load of nutrients in water could lead to the
disappearance of the more-sensitive species Lemna trisulca, Riccia fluitans, and Ricciocarpus natans and the spread of Potamogeton pectinatus, Glyceria maxima, and Glyceria fluitans. Further studies are needed to develop strategies for incorporating permanent monitoring networks to observe environmental
changes and succession of vegetation. 相似文献
26.
27.
Prof. Achille Forti 《Plant biosystems》2013,147(4):747-755
Abstract Phytosociology, ecology and chorology of snowbed vegetation in Croatia were researched. Snowbed stands, found only in freezing ravines and dolines of the Liburnian karst and Velebit Mountains (NW Dinaric Alps, NW Croatia), were classified into the association Drepanoclado-Heliospermetum (Salicion retusae, Arabidetalia caeruleae, Thlaspietea rotundifolii). Those stands, exposed mostly to the north and shaded for the majority of the growing season, were developed on more or less settled periglaciar screes and boulders in the coldest parts (bottoms, smaller ditches) of the dolines with long-lasting snow cover. Due to lower altitude of Croatian mountains, snowbed vegetation could be found only azonally, in freezing ravines surrounded by altimontane and subalpine (fir-)beech and spruce forests, where these stands manage to thrive due to specific microclimatic conditions. Snowbeds host some rare, endangered and/or protected plant species in Croatia. Vulnerability of the flora and vegetation of snowbeds in Croatia is briefly discussed. 相似文献
28.
Of the six species of sturgeons native to the Danube basin, five occurred in the upper and middle Danube. Among anadromous sturgeons were the large winter races of beluga, Huso huso, Russian sturgeon, Acipenser gueldenstaedtii, and stellate sturgeon, A. stellatus, which ascended the middle, and sometimes also the upper Danube, to spawn. Due to overfishing, followed by severe habitat alteration including damming and pollution, these anadromous sturgeons are critically endangered or extirpated from the upper and middle Danube. Acipenser gueldenstaedtii and A. nudiventris are represented only as resident non-migratory races with very small populations. The most abundant and widely distributed species is the sterlet, A. ruthenus, although it is presently limited to the middle Danube. Its population increased in some sections of the middle Danube during the past 15 years, presumably because of improving water quality, but this species remains at risk because of continuing habitat degradation. 相似文献
29.
Marko Miliša Ivan Habdija Biserka Primc-Habdija Ines Radanović Renata Matoničkin Kepčija 《Hydrobiologia》2006,553(1):231-243
We investigated the distribution patterns of particulate organic matter (POM) on travertine barriers in respect to flow velocity.
Research was conducted on the barrage-lake system of the Plitvice Lakes, Croatia. Four layers were distinguished within the
substrate (moss mat + three travertine layers) in three hydraulic habitats at three sites. Substrate samples were collected
monthly with a core sampler. The aim of the study was to explore the ability of moss mats and travertine substrate to accumulate
POM; to ascertain the role of flow velocity and to produce a model of POM distribution pattern. The average of POM deposited
in the 10 cm deep zone decreased significantly in the three sites along longitudinal profile of the system. Most POM was deposited
in the moss mats, and the amounts decreased exponentially with depth. This was observed for coarse particulate organic matter
(CPOM), ultra-fine particulate organic matter (UPOM) and total organic matter (TPOM) while fine organic matter (FPOM) deposition
appeared unaffected by depth. More POM was accumulated in hydraulic habitats of low flow velocity. Correlation between flow
velocity and POM accumulation was generally negative. Positive correlations between flow velocity and deposition rates were
noted for CPOM in moss mats and top travertine layers; the deposition of other POM fractions was negatively influenced by
the flow velocity. The influence of flow velocity decreased with increasing depth. In the deepest layers (7–10 cm) flow velocity
influenced only the deposition of the smallest particles (UPOM). 相似文献
30.
The algal growth potential (AGP) in water samples of the Danube wetland waters (1388–1426 r. km) as well as the effect of
nitrogen (in final concentration of 0.16 g l−1) and phosphorus enrichment (in final concentration of 0.02 g l−1) on the AGP was investigated by miniaturized bioassay method. Values of the total biomass of Chlorella kessleri up to the 14th day of incubation were suitable for the evaluation of trophic conditions according to the classification of
AGP. On the basis of the AGP results, trophic conditions in 55% of the samples were oligo-mesotrophic and in 46% of the samples
meso-eutrophic. A statistically significant correlation (r = 0.34) was established between the AGP of C. kessleri in original water samples and NO3 concentrations in situ. The TN/TP ratio in the wetland waters indicated a greater limitation due to nitrogen than phosphorous. Significantly lower
TSITN than TSISD, TSIChla and TSITP indicated nitrogen limited conditions. In order to quantify established nutrient limitation by the bioassay method, the effect
of added N and P concentrations on the growth rate of C. kessleri was expressed as the degree of nutrient limitation (Δr d−1) during 7 days of incubation. In the Danube wetland waters only N limitation was established in June and July; N and P limitation
in May and September while in August and October 2003 neither of the tested nutrients were limiting. From May to October 2003
the significantly highest degree of nitrogen (Δr = 0.736 d−1) and phosphorus limitation (Δr = 0.474 d−1) was determined in Lake Sakadaš. 相似文献