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We investigated the response mechanisms of plant functional traits to environmental factors at the community level in order to elucidate the adaptive and survival strategies of plants in different environmental gradients. 184 vegetation sampling plots were laid by stratified random sampling in the Saihanba region of Hebei, China. Three functional traits (leaf nitrogen content, LNC; specific leaf area, SLA; leaf dry matter content, LDMC) were measured and the community-level weighted means of the trait values were calculated by the species coverage values. Climate and terrain data were generated from the climate model ClimateAP and using ArcGIS. Finally, eight environmental factors, including climate, topographical, and soil factor, were recorded and the association with functional traits was analysed using a generalized additive model. Model testing indicated a good predictability for the SLA and LDMC while a relatively poor predictability was seen with LNC. Environmental factors that significantly impacted SLA included elevation, degree-days above 0°C, mean annual precipitation and total soil nitrogen content. In contrast, LDMC was significantly influenced by elevation, total soil nitrogen and phosphorous content while LNC was affected by elevation and degree-days above 0°C. High values of SLA and LNC were found in areas at lower elevations. The distribution of high LDMC values indicated that plant leaves have a relatively high tolerance and resistance to stress, which was better for plant to grow in the adverse environment. At the community level, clarifying plant functional traits distribution and their changes with environmental gradients is useful for the potential vegetation restoration.
Silver fir Abies alba was once an abundant tree species in the Karkonosze Mts. in Poland but its population has decreased. The aim of our study was to assess 1) the impact of canopy trees on the growth dynamics of silver fir saplings and 2) the relationship between the growth rate of silver fir saplings and the soil properties, with special regard to the soil enzyme activity. The study was conducted in the Karkonoski National Park on five experimental plots. Silver fir seedlings were planted in Scots pine, European larch, Norway spruce, silver birch and European beech stands in 1999. In 2016, we measured the diameter at breast height (DBH) and height of the canopy trees and the height, DBH, height increments, needle width and length of 100 silver fir saplings. The dehydrogenase, urease, phosphatase and asparaginase activity was analysed in organic and humus soil horizons. The height, diameter and needle dimensions of young silver fir trees were significantly different under different canopies. The urease and asparaginase activity was the highest under the larch and spruce canopy in both soil horizons. Phosphatase activity was also the highest under larch canopy but only in organic soil horizon. Young silver fir (thicket) has grown under the canopy of all tested tree species but found best growth conditions under larch and pine canopies. The relative growth of silver fir is therefore a function of both stand canopy and soil properties.
Compared to chewing lice, symbiotic and studies on their biology, ecology and survival strategies are still rare. To describe the ecology and morphology of the mite species Proctophyllodes megaphyllus, a symbiont of the alpine accentor Prunella collaris, 150 accentors were captured in the West Carpathian Mountains of Slovakia. The mites extracted from the birds were sexed and their specific body structures were measured. In total 2144 individuals of P. megaphyllus were collected from 100 accentors. Male mites collected in autumn, after the bird's postnuptial moult, reached the largest size. At the same time, mite prevalence reached maximum while the mean intensity of infestation was at its lowest. Our results suggest that mites preferred newly coated feathers after a moult and radiated horizontally, infesting birds at shared roosting sites where alpine accentors tend to reoccur. This study is one of the few evaluations of seasonal variation in ecology and morphology of feather mites in alpine conditions.
We investigated morphological variation and sexual dimorphism in two species of syntopic cave crickets (Troglophilus neglectus and T. cavicola) from Northern Balkans. T. cavicola is able to penetrate deeper in caves and stays there for longer periods than T. neglectus. Yet, it has not exhibited clearly stronger constructive (body size, elongation of appendages, increased spinulation) or reductive (eye reduction) traits than T. neglectus. Moreover, contrary to expectation, there is no clear association between more prolonged staying in a stable cave environment and overall lower morphological variability in T. cavicola. Only some of its morphological traits actually showed less while other showed more variation than in T. neglectus. While T. cavicola males are larger than females, there is no such difference in T. neglectus. This may help males of T. cavicola being more competitive towards overall larger T. neglectus. With the exception of the body size, overall sexual dimorphism was better expressed in larger T. neglectus. The morphospaces occupied by males and females overlap more strongly in T. cavicola than in T. neglectus, indicating that ecological niches of both sexes are better separated in the latter species.
Till now, the breeding biology of several North African bird populations has been little studied, particularly that of the southern populations of Iberian chiffchaff Phylloscopus ibericus. In the present study, total of 31 nests of Iberian chiffchaff were monitored in the northeastern Algeria during 2013–2017. The nesting period, clutch and brood sizes, and reproductive success of the species were determined. The first egg-laying dates of the first broods were spread over the first twenty days of April. There were significant among-year variations in nesting seasons. The Iberian chiffchaff clutch sizes averaged 4.51 eggs. The number of hatchlings and fledglings averaged 4.09 and 3.54 nestlings, respectively. There is no correlation between the nest height above the ground and the hatching and the breeding success of the species. Predation and nest abandonment were the main causes of the breeding failure of the Iberian chiffchaff in studied population, however, in general the breeding success was high – 80.7%. Breeding data for the Iberian chiffchaff at the southern edge of its breeding range in North Africa show smaller clutches and production of fewer young compared to the common chiffchaff Phylloscopus collybita in Europe.
The aim of the current study was to survey the species diversity and Leishmania infection of rodents in the Gonbad -e- Kavoos City and County, northeastern Iran, during 2018–2019. Totally, 20 rural and four urban areas endemic for leishmaniasis were selected and visited monthly. Rodent species diversity indices were calculated in different spatial and temporal scales. Species richness was also calculated using rarefaction curves to estimate the number of species in unequal sample sizes. A total of 167 rodents belonging to 7 species, 6 genera, and 2 families were collected. Rattus rattus (34.7%) and Rattus norvegicus (18.6%) were identified as dominant species. The largest Margalef and Menhinick species richness (DMg = 1.55; DMn = 1.01) and the highest value of the Shannon index (H′ = 1.71) were observed in rural areas. Seasonal abundance of the rodents varied among species and showed that the highest richness (DMg = 1.27; DMn = 0.65) occurred in spring and the highest value of Shannon index (H′ = 1.72) was noted in summer. Rarefaction curves confirmed that the highest species richness occurred in summer and spring in the rural area. Seasonal fluctuations of R. rattus and R. norvegicus have a significant impact on the changes in rodent species diversity. Investigations of Leishmania infection showed that amastigote forms of Leishmania were observed in 15.4% of smears taken from Rhombomys opimus and Meriones libycus and examined under the light microscope. The highest rate of Leishmania infection was observed during the summer.
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