Zofia Sotek

Synanthropization of the Baltic-type raised bog "Roby" (NW Poland).

Abstract Raised and transitional peat bogs, despite their considerable resistance to synanthropization, as a result of anthropogenic transformations are exposed to the colonisation by alien species. One of them is the peatland “Roby”, where, in the years 2007-2009 and 2014, floristic, phytosociological and soil studies were carried out in order to record the signs of ongoing synanthropization. Conducted observations and analyses indicated that the expansion of willows has taken place and at present they occupy a large part of the bog, encroaching into bog birch forest and successfully competing with Myrica gale. Progressive peat mineralisation and constructed surfaced roads within the bog, contributed to the appearance and wide distribution of synanthropic species, such as: Urtica dioica, Impatiens parviflora and Spiraea salicifolia. Raised bog communities and their characteristic species occur on a few fragments of the bog, in north-western part, where water regime is shaped mainly by precipitation and peat deposit is fairly well-preserved. At the same time, in the patches of these communities, a distinct unfavourable increase in the share of Molinia caerulea is observed.

Preliminary results of studies on the distribution of invasive alien vascular plant species occurring in semi-natural and natural habitats in NW Poland

Abstract In Western Pomerania, as in other areas of Europe, alien species play an increasingly important role. In particular, invasive plants tend to spread rapidly and in large numbers which may reduce diversity of native species, leading to the phenomenon of “trivialisation of flora”, and transform ecosystems. The list of invasive species (32 taxa) includes alien species occurring throughout Western Pomerania, and penetrating natural or semi-natural habitats. The second group consists of potentially invasive species (23 taxa), i.e. those distributed across the area under study and tending to increase the number of their localities in semi-natural and natural habitats, taxa invasive only locally, as well as species with missing data, which does not currently allow including them into the first group. Invasive weeds, as well as some epecophytes and archaeophytes occurring only on anthropogenic sites and tending to spread, were not taken into account. Among hemiagriophytes, the most common and troublesome ones are: Conyza canadensis, Erigeron annuus, Lolium multiflorum, Lupinus polyphyllus, Solidago canadensis, S. gigantea. Among holoagriophytes, i.e. the taxa which received the highest naturalisation status, very expansive species, successful in land colonisation, like Acer negundo, Bidens frondosa, B. connata, Clematis vitalba, Elodea canadensis, Epilobium ciliatum, Heracleum sosnowskyi, Impatiens glandulifera, I. parviflora, Padus serotina, Quercus rubra and Robinia pseudoacacia, should be given particular attention. Among the invasive and potentially invasive species, most taxa penetrate plant communities of the Artemisietea and Molinio-Arrhenatheretea class, followed by Querco-Fagetea, Vaccinio-Piceetea, Stellarietea mediae, Salicetea purpurae and Koelerio-Corynophoretea. The number of invasive species is twice as high when compared to the situation of these species in Poland; on the contrary, the number of species inhabiting anthropogenic, semi-natural and natural habitats is two times lower, while that of holoagriophytes and hemiagriophytes is 56.3% and 43.7%, respectively. It seems that in the case of some invasive and potentially invasive species, a decrease in the number of their locations may be observed from the west to the east (e.g. for Acer negundo, Bromus carinatus, Clematis vitalba, Helianthus tuberosus, Lycium barbarum, Reynoutria japonica, Rosa rugosa, Vicia grandiflora). Distribution patterns for some species (e.g. for Parthenocytisus inserta or Xanthium albinum) are indicative of a likely major role of the Odra River valley in the spreading of invasive species. It should be kept in mind that the area of the North-West Poland is poorly examined in terms of its flora, so the results provided in this paper are tentative. Nevertheless, the maps illustrate colonisation trends and directions and, moreover, have been so far the only attempt to synthesise this problem in NW Poland.

Simple yet effective: Historical proximity variables improve the species distribution models for invasive giant hogweed (Heracleum mantegazzianum s.l.) in Poland

Species distribution models are scarcely applicable to invasive species because of their breaking of the models’ assumptions. So far, few mechanistic, semi-mechanistic or statistical solutions like dispersal constraints or propagule limitation have been applied. We evaluated a novel quasi-semi-mechanistic approach for regional scale models, using historical proximity variables (HPV) representing a state of the population in a given moment in the past. Our aim was to test the effects of addition of HPV sets of different minimal recentness, information capacity and the total number of variables on the quality of the species distribution model for Heracleum mantegazzianum on 116000 km2 in Poland. As environmental predictors, we used fragments of 103 1×1 km, world- wide, free-access rasters from WorldGrids.org. Single and ensemble models were computed using BIOMOD2 package 3.1.47 working in R environment 3.1.0. The addition of HPV improved the quality of single and ensemble models from poor to good and excellent. The quality was the highest for the variants with HPVs based on the distance from the most recent past occurrences. It was mostly affected by the algorithm type, but all HPV traits (minimal recentness, information capacity, model type or the number of the time periods) were significantly important determinants. The addition of HPVs improved the quality of current projections, raising the occurrence probability in regions where the species had occurred before. We conclude that HPV addition enables semi-realistic estimation of the rate of spread and can be applied to the short-term forecasting of invasive or declining species, which also break equal-dispersal probability assumptions.

Natural conditions for the reconstruction of fish ponds and possibilities of their use in ecotourism.

Natural conditions for the reconstruction of fish ponds and possibilities of their use in ecotourism The paper comprises an analysis of the environmental impact of restoring small water retention in the Świergotka River. Hampering water flow due to river damming by 0.5 m and reconstruction of ponds will have a favourable effect on the valleys nature but may result in excessive water eutrophication in case of using these reservoirs for fish-farming. Mała retencja - analiza wpływu na środowisko i możliwości wykorzystania w ekoturystyce Rzeka Świergotka, o długości ok. 5,6 km, uchodzi do kanału ulgi, na krawędzi Polderu Cedyńskiego. W okresie przed II wojną światową została spiętrzona na 9 odcinkach, na których powstały stawy. Na skutek zniszczenia urządzeń piętrzących tylko 3 z nich wypełnione były wodą. W 2007 r. powstał projekt odtworzenia dawnego systemu retencyjnego. Stworzyło to konieczność wykonania badań szaty roślinnej i prognoz jej dynamiki w zmienionych warunkach hydrologicznych. Badania prowadzono od czerwca do października 2007 r. Zlokalizowano zbiorowiska roślinne oraz wykonano spisy florystyczne. Określono także tendencje sukcesyjne roślinności na obszarach dawnych stawów oraz ewentualne zagrożenia dla środowiska przyrodniczego. Ogółem na badanym terenie stwierdzono występowanie 109 gatunków roślin naczyniowych, dwa gatunki mchów torfowców i jeden gatunek wątrobowca. Nie odnotowano taksonów zagrożonych ani podlegających całkowitej ochronie, a jedynie cztery chronione częściowo. Na dnach dawnych stawów wykształciły się głównie olszyny bagienne lub zdegradowane zbiorowiska torfowisk eutroficznych, w których dominują pospolite gatunki wilgotnych łąk. Odtworzone stawy, ze względu na ryzyko znacznej eutrofizacji wód Świergotki w jej dolnym biegu nie mogą być wykorzystane jako hodowlane. Zlokalizowane na obszarze Natura 2000 - Ostoja Cedyńska PLB 320017, w obrębie rozległego kompleksu leśnego, są miejscem bytowania wielu gatunków ptaków. Przywrócony układ hydrologiczny pozytywnie wpłynie na różnorodność fauny, przyczyni się do zwiększenia areałów zbiorowisk związanych ze zbiornikami eutroficznymi oraz do poprawy warunków wilgotnościowych lasów doliny. Obszar ten może być wykorzystany do stosunkowo bezinwazyjnego dla środowiska kontaktu ludzi z przyrodą. Wpływa to na kształtowanie postaw proekologicznych i jest jedną z ważnych metod ochrony przyrody.