2013. május 4., szombat

Takács A. et al. (2013) Preslia

Takács A., Schmotzer A., Jakab G., Deli T., Mesterházy A., Király G., Lukács B. A., Balázs B., Perić R., Eliáš P. jun., Sramkó G., Tökölyi J. & Molnár V. A. (2013): Key environmental variables affecting the distribution of Elatine hungarica in the Pannonian Basin. – Preslia 85: 193–207.

Elatine hungarica Moesz is a small wetland ephemerophyte that occurs and is classified as extinct, data deficient or a very rare and endangered taxon in most countries in eastern and central Europe. Based on literature and herbarium data, supplemented by 160 field records collected between 1998 and 2011, we present the currently known distribution of this species in the Pannonian Basin, which mostly but not exclusively includes Hungary. Within the Pannonian Basin this species is distributed throughout Hungary, with sporadic occurrences in Romania, Serbia and Slovakia. The temporal distribution of floristic records is very uneven. This species was recorded only in 27 years during the last 213 years (1798–2011). When examining presence/absence data for most of the 20th century, we found a significant correlation between the number of records of this species in a given year and two key, but not independent, environmental variables: rainfall and the extent of the area inundated in the same year. In the more intensively documented period between 1998 and 2010, there is only a significant correlation between the numbers of records of this species and the extent of flooding, which is because there is a delay in the effect of an increase in rainfall. The peak occurrence of records in the 1940s and 1950s is associated with extensive rice production in Hungary. Today, most records are for agricultural fields that are subject to flooding and becoming temporary wetlands. The comparison of recent and past distributions of E. hungarica reveals a consistent and marked regional difference; whereas this species is not rare along the Tisza river and its tributaries, it is markedly scattered in similar habitats near the Danube.

ephemerophyte, flooding, Hungary, inland water, Isoëto-Nanojuncetea, Elatinaceae, mapping, rainfall, rice weeds, Romania, Serbia, Slovakia, temporary ponds

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