Perry, J.M. & A.M. Perry (2014): A new locality for Cypripedium calceolus from the Rodopi Mountains, Bulgaria.- J. Eur. Orch. 46 (1): 31-40.
An important new locality for Lady's Slipper orchid (Cypripedium calceolus) is reported from the Rodopi Mountains, Bulgaria. Up to now, the species has only been found in two localities in Bulgaria, and at one of these sites it has not been recorded for many years. The Authors discuss the current distribution of Cypripedium calceolus on the Balkan Peninsula, and highlight the fact that these isolated populations from the Rodopi Mountains are of great conservation significance as they represent the most south-eastern outpost for Lady's Slipper Orchid (Cypripedium calceolus) in Europe.
Yordanova, M. (2016): Orchids of the Rodopi Mountains. Sofia: Wild Rodopi. pp.130
This book aims to arouse the interest of amateur naturalists and orchid lovers about the diversity, beauty, ecology and conservation status of wild orchids in the Rodopi (Rhodope) Mountains, and to encourage a positive and responsible attitude towards their fragile and vulnerable beauty. The book comprises informative texts about 60 species of orchids occurring within the Rodopi (Rhodope) Mountains. The book is illustrated with 163 colour photographs, 6 black-and-white photographs and 12 black and white illustrations.
Muijen, T. (2014): Trigrad - Yagodina Herpetofauna Survey. Wild Rodopi & HAS Hogeschool. pp.42
Because of the lack of detailed herpetofauna surveys focusing on the distribution of species in the Western Rodopi (Rhodope) Mountains, the local distribution of many species of herpetofauna in this mountain range is still poorly known. This herpetofauna survey investigated which species of reptiles and amphibians are present within the Trigrad-Yagodina Karst Region, a part of the Western Rodopi (Rhodope) Mountains famous for its deep gorges and caves, and which is covered by extensive forest, scattered by meadows, stony pastures and river valleys. By means of active field surveys (area search) and oral communication with local people, this research studied which species of reptiles and amphibians are present in all different habitats of the study region, and identified their local distribution patterns within the Trigrad-Yagodina Karst Region. Within the study region, 16 species of herpetofauna were found including 4 species of lizard, 5 species of snake, 6 species of frogs and toads and 1 salamander. This low number of species, especially of reptiles, in comparison to the species richness of the whole of Bulgaria is probably due to the high altitude and location of the study region within the approximate centre of the Western Rodopi (Rhodope) Mountains. Most species were found in the lower parts (river valleys) of the region and only one species was restricted to the higher mountain parts. The most abundant species were Common Wall Lizard (Podarcis muralis), Eastern Green Lizard (Lacerta viridis), Common Toad (Bufo bufo), Marsh Frog (Pelophalyx ridibunda) and Yellow-bellied Toad (Bombina variegata).
Cardinaals, J. (2015): Red-backed Shrike Survey Yagodina-Trigrad Karst Region: Habitat preference related to (nest) predation. Wild Rodopi & HAS Hogeschool. pp.53
Global extinction of species increased the need for nature conservation. One of the species that is prone to this extinction is the Red-backed Shrike (Lanius collurio), which showed a significant population decline in western and northern Europe. The disappearance of traditional pastoral activities from these areas appears to be the main cause of this decline. However, the factors behind this remain unclear. These agricultural changes not only make the area less suitable for Red-backed Shrikes, but also increase the suitability for Corvids, which are the main nest predators of Red-backed Shrikes. As nest predation is the most limiting factor to reproductive success, it might play an important role in the decrease of Red-baked Shrike in several countries. In order to place nest predation in these areas in perspective, it is necessary to have an impression of the role of nest predation in a stable population first. In this study Red-backed Shrikes and their potential predators are surveyed in the Western Rodopi Mountains (Bulgaria), along with behavioural observations aimed at capturing prey-predator interaction. In total 125 Red-backed Shrike observations were made, comprising 73 males, 9 females, 38 pairs and 5 unknown individuals. During the survey, 10 potential predators were recorded in the study area. Of these predators, 6 were recorded within direct area of a Red-backed Shrike, during the behaviour observations. Of those, the European Jay (Garrulus glandarius), the Hooded Crow (Corvus cornix), and the Peregrine Falcon (Falco peregrinus) showed direct interaction with the Red-backed Shrike.