Comparative analysis shows that the concentration of biodiversity richness in the former Yugoslav Republic of Macedonia ranges from 54 times (in fishes) up to 246 times (in birds) higher than the mean European Species Diversity Richness. In this context, the most significant changes are occurring in aquatic habitats - natural lakes, wetlands, and in specific sections of major rivers. Grassland ecosystems have also changed significantly, with large areas having been turned into arable land. Threats to forest ecosystems are varied and include desiccation, die-back processes, forest fires, illegal logging, and various diseases.