Recent trends in the European Black StorkCiconia nigra population are geographically distinct: range expansion and adaptation to human activity dominate in western and central Europe, while declines-probably induced by landscape change-are reported in the east. We studied the large Lithuanian Black Stork population in the transition zone to explore whether, and how, the detrimental influences of recent Baltic landscape changes are balanced by the West European tendency of behavioural adaptation to human activity. Based on monitoring in sample plots, the current population was estimated at 650-950 pairs, indicating a significant decrease (possibly over 20%) during the last two decades. In comparison to the Latvian and Estonian populations, however, this decline is smaller, and the reproductive success remains at a high level [66% breeding success and 2.99 ± 0.97 (SD) fledglings per successful attempt, [2000][2001][2002][2003][2004][2005][2006]; this north-south gradient suggests a climate-mediated impact of habitat degradation in the Baltic countries. The storks are also nesting closer to forest edges and in younger stands than 15-30 years ago, which has probably reduced the nest-tree limitation, as indicated by an increased use of large oaks. Thus, habitat degradation and adaptation seem to be taking place simultaneously in the Lithuanian Black Stork population, as was expected from its geographical location. In general, our study supports the view that, whenever possible, species conservation strategies and the use of indicator species should be geographically explicit.
Abstract. In the mid-20 century, Lesser Spotted Eagle (Aquila pomarina) was considered to be one of the most abundant species among the birds of prey in the forests of Lithuania. The estimates of the national population changed from 300500 to 1,5001,800 pairs in 1994 and 2005, respectively. Changes in the population estimates did not reflect the actual population trend, but rather the level of investigation of the species in the country. In reality, the current status of the species population is unknown due to the lack of regular, nationwide monitoring. The aim of this work was to estimate the status of the Lesser Spotted Eagle population in Lithuania. Field studies in 10 sample plots in various regions of Lithuania during the period 20032006 showed that the number of breeding pairs declined by 31% on average as compared to the period 19801998. We suggest that the population of Lesser Spotted Eagle decreased by 26% across the country during the period 19802006. Possible reasons of such decline are discussed in this study.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.