Wyniki wyszukiwania - BazTech

1

Migration of herb layer species into the poorest post-agricultural pine woods adjacent to ancient pine forests

Orczewska A., Fernes M.

Polish Journal of Ecology

|

2011

|

Vol. 59, nr 1

75-85

EN

The recovery of species composition typical for ancient forests in recent woods is a very slow process and may last for decades or even centuries. It is enhanced only when postagricultural woods are adjacent to ancient ones. However, even in such a situation of the spatial contact of both forest types, colonization of recent woods by true forest species is a gradual process. According to studies focusing on the behaviour of individual species and their colonization rates into recent woods, it can be concluded that in more fertile habitats the migration process proceeds faster than on poorer sites. Thus, studies were conducted on light, acidic soils both in ancient and in adjoining post-agricultural pine woods (the Dicrano-Pinion Libb. 1933 alliance) and were focused on the process of the colonization of the herbaceous layer by woodland flora in recent woods. In eight transects 80 m in length perpendicular to the ancient/recent ecotone and consisting of 10 sample plots of 16 m2 laid out at intervals of 4 m, the percentage cover of herb layer species was recorded. The migration rates (based on the occurrence of the farthest individual and on the occurrence of the maximum cover of a species) for 12 forest species were calculated. The mean migration rate for all species reached 0.54 m yr[^-1] when based on maximum cover and 0.67 m yr[^-1] when based on the farthest individual and appeared to be lower than those reported in investigations in more fertile and moister habitats. The migration rates for individual species ranged from 0 to 1.21 m yr[^-1] and were also lower than in more fertile, black alder woodlands. The migration pattern of Vaccinium myrtillus L., the most abundant species in pine woods, fits the model based on the establishment of isolated individuals. The cover of most woodland species increased with the increasing age of a recent wood. Herb layer recovery on such sites is slower than in the more productive, fertile habitats of broadleaved forests. The ancient and recent pine woods investigated here differed in herb layer species composition despite the secondary succession having lasted for over 50-60 years.

2

Effectiveness of Korean pine (Pinus koraiensis) seeds dispersing by small rodents in fragmented forests

Yang Y., Yi X.

Polish Journal of Ecology

|

2011

|

Vol. 59, nr 2

413-422

EN

The effectiveness of dispersers on seeds of Korean pine (Pinus koraiensis Siebold et Zuccarini) was investigated in three fragmented stands and one primary stand. The proportion of Korean pine trees was less than 7% in the fragmented stands but more than 90% in primary stand. Five estimates related seed dispersal (proportion of removed seeds, scatter-hoarded seeds, cache dynamics, dispersal distance and microhabitat) were assessed to see the effect of forest fragmentation on the probability of seed dispersal of Korean pine seeds. Our results indicated fast seed harvest of Korean pine by small rodents at the seed stations and no difference among the four stands. Scatter-hoarding rodents were potentially important in promoting natural regeneration of Korean pine as revealed by high proportion of seed removal (up to 50%), short seed lifetime from the seed release locations and lower proportion of seeds remained on the ground surface. Although a proportion of seeds were scatter-hoarded in fragmented stands, no seedling successfully established due to heavy predation. Dispersal distances were strongly left-skewed in fragmented stands, indicating that fragmentation is likely to be disadvantageous for longer distance dispersal. The effective dispersal was suffered from a very heavy cost as accompanied by a great portion of seed predation and lower level of scatter-hoarded seeds. Failing to see seedling establishment in fragmented stands rather than in primary stand indicated that fragmentation and deforestation have negative effects on dispersal behavior and consequently seed destination. Artificial tree plantation and pinecone protection are highly recommended for Korean pine regeneration.

3

Seed dispersal by the Rook (Corvus frugilegus L.) in agricultural landscape - mechanisms and ecological importance

Czarnecka J., Kitowski I.

Polish Journal of Ecology

|

2010

|

Vol. 58, nr 3

511-523

EN

The study aimed to evaluate the role of the Rook Corvus frugilegus in the long-distance seed dispersal in agricultural landscape. According to the literature, Rooks feed in the distance 0.3-1 km from the breeding colonies and 10-40 km from winter communal roosts, and these can be also the potential seed dispersal distances. We concentrated on the dispersal of diaspores of ornitochorous species and weeds (called non-ornitochorous) taken probably incidentally during foraging for other edible plant material. The contents of 528 pellets was analysed, 304 were collected at six sites of breeding colonies located in five rural parks and in one park on the city outskirts, and 224 under three winter roosts in the cities. Seeds representing 45 taxa were found, the most important groups among them are: ornitochorous species (10 taxa), non-ornitochorous (27 taxa, mainly weeds and ruderal species) and cereals (4 species). The mean number of seeds varied between 221 and 442 seeds per 100 pellets in the case of breeding colonies, and between 102 and 347 for wintering roosts. Fruits of ornitochorous species are an important element of the diet of the Rook: Cerasus avium and Fragaria sp. during breeding season and Vitis sp., Sorbus aucuparia and Sambucus nigra during winter. Nonornitochorous species are present in pellets in lower numbers and frequencies than ornitochorous ones and they can be divided into two groups: those transported during breeding season (mainly Stellaria media) and those during winter (Setaria sp. and Echinochloa crus-galli). We estimated that the number of non-ornitochorous seeds transported by birds from the biggest observed winter roosts can exceed 400 thousands seeds per month. The value is much lower in the case of the biggest breeding colony: approximately 16 thousands of propagules. We also checked if species found in pellets can germinate in natural conditions under the studied colonies. Viable individuals of 15 nonornitochorous and of one ornitochorous species were found there, and it was observed that disturbances of soil surface promote germination of some analysed species. @eng

4

The potential role of nests of Black-billed Magpie Pica pica L. in accumulation and dispersal of seeds in agricultural landscape

Czarnecka J., Kitowski I.

Polish Journal of Ecology

|

2008

|

Vol. 56, nr 4

673-682

EN

The study aimed to describe the seed pool accumulated in the nest material of Magpie Pica pica, and to determine the importance of this mechanism of seed dispersal for such ecological processes as colonization of new habitats and expansion of alien plants. The seedling germination and seed extraction methods were used to determine seed abundance in the soil layer, the inner layer, and in the lining of 9 nests collected in three types of agricultural landscape: the first with domination of arable fields; the second with similar shares of arable fields and other landscape elements such as meadows of different types, shrubs, tree clumps and rushes; and the third with domination of lowland hay meadows. In all the nests, considerable numbers of diaspores were found (from 26 to 371 seeds per nest, belonging to more than 80 taxa). The main plant groups found in the nests are species connected with field roads, weeds and ruderal species, but also meadow and brushwood species were found there. The soil was gathered by birds from habitats with low vegetation cover and large areas of bare soil. Although the structure of seed pool of nests suggests that soil was mainly collected in the close vicinity of the nests. future location, this mechanism of seed dispersal can probably be involved in long distance dispersal. Seeds of two rare kenophytes: Erucastrum gallicum (Willd.) O. E. Schulz and Diplotaxis tenuifolia (L.) DC were found in the material of nests localized more than 100 m away from their closest populations. It can be assumed that this mechanism of seed dispersal can play a potential role in the expansion of alien plants and colonisation of new habitats.