Assessment of ornithochory in the north-western part of the Podunajská nížina Lowland (SW Slovakia)

Abstract

Plant seeds and fruits can be dispersed in several ways; diaspore dispersal by ornithochory is common to many plant species. The aim of the study was to assess the birds’ potential in dispersal of woody species which are present in the riparian vegetation of two streams with tributaries in the lowland of SW Slovakia. We examined three hypotheses related to riparian woody vegetation: (1) ornithochory plays an important role in the formation of riparian vegetation, (2) riparian vegetation serves as a food source for bird species in highly deforested lowland landscape, (3) there are differences among selected indication groups of woody plant species by types of diaspore dispersal. Four indication groups represent natural alluvial woody vegetation, adjacent forests, other autochtonous woody species and non-native species. Characteristics, such as diaspore type, weight, maturity, and dispersal patterns within four indication groups of woody species were analysed. The occurrence of bird species, feeding strategy and weight categories of birds were assessed. In addition to field research, the data were obtained from the work of Turček “Ecological relationships of birds and woody plants” and from the D3 Dispersal and Diaspore Database. The results show a high proportion (53%) of plants with fleshy fruits, consequently endozoochory (including ornithochory) appears to be the dominant pattern of diaspore dispersal of riparian woody species of the study area, and the second is anemochory. Evident differences in diaspore dispersal patterns were found within the indication groups. Five bird species participate in dispersal of more than 50% of the assessed woody plants. The analyses showed that a significant share of small-size birds (50–100 g) and large-size birds (500–1,000 g) spread riparian vegetation woody species.