Integrated population monitoring of sandmartin Riparia riparia-an opportunity tomonitor the effects of environmental disastersalong the river Tisza

From January to March 2000, the entire length of the River Tisza suffered an appallingly seriousenvironmental disaster when the collapse of tailings dams belonging to upriver Romaniangold mines caused severe pollution by cyanide and heavy metals. This pollution was the directcause the death of flora and fauna in the Tisza along its length and threatened the entireecosystem of the river, one of the last remaining natural major rivers in Central Europe almostfree of large-scale man-made developments. The river Tisza is such an important breeding androosting area for large populations of several insectivorous and piscivorous bird species thatseveral Important Bird Areas (IBAs) have been established along its course. Most of thesespecies are migrants that fortuitously happened to be elsewhere in their travels when the pollutionoccurred, but the scale of the problem was such that delayed impacts can be expected.As it happens, long-term integrated monitoring work on the Sand Martin Riparia ripariabreeding population along the river Tisza in Hungary has been running since 1986 under the gis of MME and BirdLife Hungary. This project also happens to monitor the population sizeand distribution of Kingfisher Alcedo atthis and so was well placed to begin comprehensivemonitoring of the short-, mid- and long-term effects of this disaster. The breeding populationsof these two species along the river Tisza depend predominantly on the supply of their food,the fauna of the river and its flood zone. The two species, by macabre good fortune, happen tobe the ideal models for studying the effects of the disaster on insectivorous and piscivorousbirds. Detailed studies in 2000 following proven protocols, such as fieldwork and chemicalanalysis of the feathers, revealed that the pollution has had no measurable effects on populationsizes, distribution and reproductive success, and that the level of heavy metals in the foodchain of insectivorous birds did not increase. However, precedent and the scale of the disastersuggest that the lack of immediate effects means that there may well be secondary effects inthe longer term from subsequent events, such as floods and droughts. The disaster has broughtgreater international awareness, which may help to reduce pollution or make such incidentsless likely. Our investigation underlined the importance of monitoring in these kinds of habitats,because it showed that some assumptions about the consequences of the accident werewrong; in the absence of data, there is a risk in such circumstances of misinterpreting the outcome.

T. Szep, Z. Szabo D. and J. Vallner, Ornis Hungarica 12-13: 169-182. 2003