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In 13 forest reserves situated in southern Poland, 68 study plots were established in two regions: the Jurrasic Upland and the Silesian Upland. In these plots, size 10 m × 10 m divided into 100 subplots 1m² each and randomly placed in various forest communities, percentage cover of all species in ground layer was recorded. Relationships between highly invasive alien plant species, Asiatic small balsam Impatiens parviflora DC., and indigenous species, was estimated using various indexes of species richness and diversity. They were: Hill’s numbers (N₀, N₁, N₂), ShannonWiener’s index at the level of a subplot, alpha diversity (species richness within sites), and beta diversity (species richness among sites) at level of a study plot. The subplots with a presence of I. parviflora were compared with those where only native resident species occurred. The study has shown that subplots with the occurrence of I. parviflora are characterized by higher species richness and diversity of native plants independently on vegetation type. The frequency of I. parviflora was negatively correlated with beta diversity of study plots but there was no association with values of alpha diversity. In oak forest, alder carrs and floodplain forests the negative correlation between percent cover of I. parviflora and species richness, as well as cover of the herb layer was observed. The percent cover of I. parviflora was positively correlated with number of native species in beech forest and with their total cover in mixed coniferous forests. However, in natural well-preserved forest phytocoenoses I. parviflora avoids patches characterized by high cover of ground layer species and colonizes empty sites as an additional element of a community.
The paper presents preliminary results of research on the influence of selected components of the dynamics of oak-forest communities (tree death and activity of animals) on changes in the density of Impatiens parviflora. The rate, intensity and duration of changes in the density of this species are analysed.
In this study, we examine the pattern of occurrence of Impatiens parviflora in Central European oak forests over time and its ecological requirements within these types of communities. Research was based on phytosociological data collected in 3776 relevés. A modified TWINSPAN algorithm were used to distinguish the groups of oak forests. The ecological preferences of the I. parviflora and studied communities as well as differences between invaded and non-invaded vegetation plots were analyzed using mean weighted Ellenberg indicator values (EIVs). Finally, both the temporal pattern of I. parviflora participation and changes in its coverage in the studied communities were analyzed. Our study confirmed a high adaptability of this species with respect to temperature, moisture, soil reaction and nutrients and determined its broad ecological optimum in oak forests. However, it also revealed both a greater sensitivity of some communities within Central European oak forests to the invasion of I. parviflora and differences in habitat conditions between invaded and non-invaded vegetation plots. This suggests that the habitat niche of I. parviflora within oak forests is not accidental. The analysis of temporal changes in the frequency of I. parviflora confirmed a 20% increase in relevés over the last 50 years. However, we did not identify any statistically significant rise in the coverage of I. parviflora in oak forests specifically during the studied period.
The aim of the present study was to determine how internal diversity of oak-hornbeam forest modifies the course and effects of infestation of small-flowered balsam (Impatiens parviflora) with rust Puccinia komarovii. The study investigated the effect of the disease on the demography of the population, and the habit and biomass allocation of the infested specimens, as well as the initiation of non-specific defense mechanisms. It was shown that: 1) the percentage of infected specimens was independent of the undergrowth-coverage rate and of the I. parviflora density; 2) infected populations differ from healthy ones in the seasonal dynamics of abundance changes; 3) high mortality is observed as early as May and the first part of June, i.e. it pertains to specimens, which did not begin reproduction; 4) the presence of infection and its intensity stimulate the growth of the stem and the hypocotyl; 5) fresh weight of infected specimens is by almost 30% lower in comparison to the weight of uninfected plants; the weight of badly infected plants decreases by 20% in comparison to the less severely infected balsam plants; the weight of generative organs drops most significantly, even by over 50%; 6) biomass allocation does not fluctuate considerably; 7) reproduction effort expressed by the ratio of the weight of fruits (or only seeds) to the total biomass shows a distinct downward trend; 8) the environmental factor does not affect the force of defense mechanisms, the strength of biochemical response of diseased plants depends on the degree of their infestation.
This study investigated the extend to which the snail Columella edentula is more strongly associated with the small balsam Impatiens parviflora than with other plants in the herb layer of an oak-hornbeam forest, and to interpret the character of the interaction Impatiens parviflora - Columella edentula. Numbers of C. edentula and rates of colonization were compared on various plant species under natural and laboratory conditions. Seasonal variation in snail abundance on I. parviflora was observed on permanent plots. The leaf injuries caused by C. edentula were localized in respect of the morphological and anatomical structure of leaves. The results show that I. parviflora is one of the plant species of the herb layer that are most abundantly colonized by this snail in oak-hornbeam forest. Snail finds a plant particularly suitable as a place for resting. The most favoured attachment site is on the underside of the leaf, along the midrib, which provides the highest and relatively stable humidity, as well as protection from direct sunlight and predators. I. parviflora is also a food for the snails, but they do not eat these fragments of leaves where calcium carbonate is accumulated.
Valleys of large rivers, like Bystrzyca which is one of the largest Odra river tributaries, are prone to invasions of alien plant species. The Bystrzyca river valley in Krasków-Jarnołtów section is a part of a protected landscape area but it is relatively modified by human activity. Reinforcement of the river bed may have caused the appearance of invasive species, while the process of their penetration to protected areas is a serious threat to natural plant cover. The article contains basic data concerning synanthropisation and distribution of five invasive species (Impatiens parviflora, Reynoutria japonica, Reynoutria sachalinensis, Solidago canadensis, Solidago gigantea) found within the investigated area.
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