Wyniki wyszukiwania - BazTech

1

Influence of habitat structure and conditions in floodplain forests on mollusc assemblages

Kappes H., Kopeć D., Sulikowska-Drozd A.

Polish Journal of Ecology

|

2014

|

Vol. 62, nr 4

739--750

EN

Alder floodplain forests are a rare and threatened forest type in Europe. These forests can be very rich in mollusc species. The intermediate disturbance hypothesis predicts that species richness should peak at intermediate inundation frequency, that is, at intermediate elevation above the river level. We additionally hypothesized that constantly high soil moisture can distort the usually positive correlation between the amounts of downed deadwood and snail richness, and that tree stems might be more favourable than deadwood because their vertical structure provides a better refuge during inundation events. To this end, we sampled molluscs from a core area of 20 × 20 m from eight alluvial forests with black alder in the surroundings of Łódź, Central Poland. In each core area, substrate was collected from eight random plots (0.25 m2 each). We also recorded soil pH, vascular plant species and mosses diversity, along with other structural variables. Plant indicator values were calculated according to Ellenberg. Soil quality (amongst others: soil pH, reactivity value, nutrient and moisture availability) decreased with increasing elevation above the river level. In the plot samples, we found a total of 18,497 individuals from 52 species. Mollusc species richness dropped stronger than densities with an increasing elevation above the river level. Main influences on mollusc richness and abundance originated from positive correlations with soil pH and moisture. An additional hand sampling campaign on tree stems and deadwood items in the core area revealed that coarse woody debris items on average carried twice as many individuals as did tree stems. Deadwood and tree stems supported similar numbers of snail species per item, but beta-diversity was higher on deadwood. Consequently, Jackknife 2 predicted that deadwood is utilized by about 46 species, whereas tree stems only support about 39 species. Our results indicate (1) that mollusc richness peaks at low elevations above normal water level in this type of forest, (2) that intact hydrological regimes are associated with high soil quality and mollusc biodiversity, and (3) suggest that coarse woody debris adds resources, refuges and a dispersal agent for the alder forest floor fauna.

2

Analiza zmienności i korelacji wybranych cech fizycznych nasion olszy czarnej

Kaliniewicz Z., Trojanowski A.

Inżynieria Rolnicza

|

2011

|

R. 15, nr 8

167-172

PL

Dokonano pomiarów prędkości krytycznej unoszenia, grubości, szerokości, długości, kąta tarcia ślizgowego i masy oraz wyznaczono współczynniki sferyczności nasion olszy czarnej, zebranych z 3 różnowiekowych drzewostanów nasiennych. Do opisu i analizy cech wykorzystano analizę wariancji z klasyfikacją pojedynczą, korelację oraz regresję jednej zmiennej i wielu zmiennych.

EN

Measures of critical speed of lifting, thickness, width, length, sliding friction angle and mass were taken. Moreover, spherical coefficient of black alder seeds collected from three seed tree stands of different age was determined. The analysis of variance with single classification, correlation and regression of one variable and many variables was used for description and analysis.

3

Differences in defence strategies against herbivores between two pioneer tree pecies: Alnus glutinosa (L.) Gaertn. and Betula pendula Roth.

Giertych Marian J., Karolewski Piotr, Żytkowiak Roma, Oleksyn Jacek

Polish Journal of Ecology

|

2006

|

Vol. 54, nr 2

181-187

EN

The different defence strategies of trees against herbivores are very often connected with succession status, leaf life span and the level of secondary metabolites. We examined the effect of simulated leaf grazing on the differences in the leaf life span and defence chemistry of two pioneer tree species that belongs to the same family (Betulaceae), black alder (Alnus glutinosa (L.) Gaertn.) and European white birch (Betula pendula Roth.). At the beginning of the growing season, mature leaves were perforated using a paper punch. The holes removed about 10% of the leaf surface. Each species was represented by six trees - one branch was chosen for perforation and one branch as a control. All leaves were counted every week until their abscission. Additional damages caused by grazing insects were also noted.Undamaged birch leaves were held much longer than those of alder. The average difference in half leaf life span between control and perforated leaves was 28 days in birch and 6 in alder. The control unperforated alder leaves were significantly (P <0.05) more often grazed by insects than those that were perforated. Leaf perforation in alder increase phenolic concentrations in the new, young leaves. In birch we did not observe these changes.The comparison of alder and birch indicate that the species with similar successional status can have different strategies of leaf defence. The birch leaves were characterized by a longer leaf life span, constitutive defence, a lack of induced defence accumulation of phenolics and earlier shedding of damaged leaves in comparison to the control. The black alder foliage had a shorter leaf life span, induced defence reaction (producedmore phenolics after perforation), and only slightly earlier shedding of damaged leaves than the control.