How the Number of Orchid Populations Quickly Declined in the Czech Republic During the Last 150 Years? The Case of Less Threatened Species
Abstrakt
In the contemporary period of massive extinction of species it is especially important to understand the way in which species distribution patterns and abundances change over time. This may be affected by the political regime.
In Czechoslovakia, before 1948, the traditional management practice was fields and meadows that were mown or grazed, with low intensity of agriculture based on small fields and low application of fertilizers. After 1948, the practices in Czechoslovakia changed dramatically, with small fields being merged into huge fields and subsidies provided for fertilizers, so that the amount of nutrients in the soil increased rapidly and negatively affected many rare species.
After the change in the regime in 1989, subsidies for fertilizers stopped, which caused a great decline in their use and subsequent increase in the distribution of many rare species. In a previous study, Štípková and Kindlmann (2021b) analysed, for different species of orchids, the temporal trends in the numbers of sites, where living populations of the species studied were reported at the time considered.
They used a dataset of orchid records of the Nature Conservation Agency of the Czech Republic, which covers a period of about 150 years and includes more than 115 000 records. Contrary to these analyses, which were done for rare species of Czech orchids, i.e., for threat categories A1 and C1, based on the Red List classification for the Czech Republic, here we present results for the less endangered species: for threat categories C2-C4.
We conclude that the numbers of sites, where living populations were reported, declined less in species with many historically recorded sites, maybe because these species are widely distributed and not very demanding in terms of site quality. This decline was largest during the communist era (1948-1989), compared with other periods.
In the case of species with few historically recorded sites this decline was much greater, maybe because of their special requirements on site quality, but not dependent on the time period. This indicates that quality of the sites of extinction-prone species should be maintained, which is not so important in the case of the more abundant species, as their extinction is less likely.
The fact that these losses occurred mainly during the communist era may indicate that the large disturbances occurring then (conversion into building sites, large inputs of pesticides or artificial fertilizers applied to adjacent fields, etc.) were the cause.