Publication details
Plant invasions in floodplain habitats of lowland rivers: a case study from the south-eastern Czech Republic
| Authors | |
|---|---|
| Year of publication | 2008 |
| Type | Article in Proceedings |
| Conference | Towards a synthesis: Neobiota book of abstracts. |
| MU Faculty or unit | |
| Citation | |
| Field | Botany |
| Keywords | river floodplain; biological invasion; habitat preference; exotic plant; archaeophyte; neophyte; level of invasion, Morava River |
| Description | Riparian systems show one of the highest proportions of non-native species in the current landscape. Common explanation is that vegetation along watercourses is affected by specific processes, e.g. frequent disturbances, high propagule pressure and a long history of human impact. However, very few attempts were made to to compare the occurrence of invasive species in different vegetation types in river floodplains, although this is important for understanding of the invasion process in riparian vegetation and also has implications for invasive plant management. This study provides such comparison and determines the relationship between non-native species and selected landscape characteristics. Two segments of the floodplains of the Dyje and Morava rivers (about 90 km of river courses) were sampled in the south-eastern part of the Czech Republic. Stratified random sampling design was used to avoid subjective choice of sites with invaded vegetation. Thus, the results are supposed to show undistorted pattern of plant invasion among plant communities. The sampling plots (in total 135) were stratified according to the habitats types of the Natura 2000 habitat mapping and inundation maps (floods occurring once in 20 and 100 years). Main types of vegetation and presence of invasive species were estimated in the circles with 100 m diameter around each plot. Specific features of adjacent landscape (roads or watercourses) were also recorded. Habitats with the highest proportion of invasive species, neophytes and archaeophytes, were ruderal sites and forests clearings, i.e. those with the most distinctive disturbance regime. Neophytes had stronger affinity to woodlands and associated habitats like tree plantations or forest clearings, whereas archaeophytes occupied semi-natural vegetation like mesic and alluvial meadows. The most successful species were: Aster lanceolatus s. lat., preferring forest clearings; Acer negundo, dominating the non-native tree plantations; and Solidago gigantea in ruderal vegetation. Significant positive correlation between the numbers of archaeophytes and neophytes was found across all habitats, which suggests that habitat types prone to invasion of one species group are also suitable for another one. The number of invasive species increased in plots with more invasive plants in their surroundings. Regression trees revealed that habitat type was the most important factor separating plots with high and low numbers of archaeophytes, neophytes and invasive species. For the subset of invasive species, the second most important factor was flood frequency; significantly higher proportion of invasive species was found in plots from areas, which are frequently flooded. Archaeophytes were more abundant in plots located closer to roads and the proportion of neophytes increased with frequent inundations. These results indicate that certain floodplain habitat types are at a higher risk of plant invasion; especially when exposed to repeated inundation in a short time period. |
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