Targeted support for endangered butterfly species based on a combination of flexible habitat management and evaluation of detailed biological data

Description

The aim of the project is to use a flexible management practice to expand the suitable area for 4 target butterfly species surviving for a long time in the nearby complex of Prokop valley to allow their future population growth and expansion

Summary of project results

In this project, we aimed to highlight the crucial role that nature-like habitats play in preserving biodiversity within urban environments. Cities often hide valuable protected areas that serve as sanctuaries for various plant and animal species. However, many other important sites lack proper protection, leading to their destruction—either through conversion to agricultural land and development or due to overgrowth from lack of management. These sites are often vital for the survival of endangered species, even if only as temporary refuges or sources of food. Moreover, managing these areas outside officially protected zones allows for more flexible and rapid interventions.

In Prague, near the Prokop Valley, we focused on four selected sites, two of which were newly established on former arable land. Our goal was to improve the condition of local habitats for model groups of organisms, including a repatriated population of a butterfly species that had previously disappeared from Prague.

The main objectives of the project were:

1. To expand the habitat for four endangered butterfly species (the dusky large blue, the scarce large blue, the southern festoon, and the six-spot burnet) through flexible management outside protected areas, enabling them to extend their range beyond the Prokop Valley.
2. To support the reintroduced population of the vulnerable eastern baton blue, which had previously disappeared from Prague, and ensure its further spread within the city.
3. To monitor and evaluate the impact of management interventions on target and non-target species, and optimize site management based on the collected data.
4. To actively share the findings with both the expert community and the general public, raising awareness about the importance of managing non-forest habitats and the species that depend on them.

To improve the potential of local habitats, we implemented several types of management activities at the targeted sites, including their flexible forms. The diversity of activities is very valuable for maintaining the mosaic character of the habitats, which ultimately leads to an increase in their conservational and natural potential. The flexible form of the individual types of care involved the rapid application of small-scale interventions, which could quickly resolve emerging problems – such as the rapid removal of expansive plant stands, overly regenerating tree shoots, or the removal of desiccated nectar plants, leading to their quick rejuvenation and reblooming. Specifically, we worked with types of management activities such as cutting down overgrowing trees and shrubs, grazing understory with a herd of goats, a herd of sheeps and goats,  grassland mowing either conventionally using machinery or more heterogeneously with hand mowing, disturbance of the turf by mechanization and seeding and partially mowing patches with nectar-producing plant species.

We carefully monitored the impact of these interventions on model groups of organisms, including a detailed study of the repatriated population of the Polyommatus thersites.

Many activities related to habitat management actively involved representatives from the public – whether they were students from local schools or members of the general public with a positive attitude toward nature. Thanks to these activities, we created a system of sites with a relatively high variability of habitats, from forest-steppe fragments to dry meadow ecosystems (including the newly established habitats). We also received numerous positive responses from local residents who use these areas for recreation. A significant result is the creation of a system of sites outside protected areas, which can significantly benefit both endangered species of organisms and local residents.

The main outputs of the project are primarily map-based resources with the localization of individual management activities at the localities and their detailed descriptions. Thanks to these resources, the end user (the Prague City Hall) can quickly get an idea of the implemented interventions, which can be seamlessly followed up with further planned or ongoing management efforts. Other results include detailed datasets and documents from monitoring, demonstrating the development of model groups of organisms during the project implementation period.

The positive impact of the applied management on local communities of organisms is evidenced by detailed monitoring results. Over three years of habitat management, the total number of butterfly species, including conservation-significant species, increased. Populations of all selected model butterfly species showed stable or increasing trends, with most of them successfully reproducing at the sites. The repatriated population of the Polyommatus thersites even had the highest abundance in the second year of the project since its establishment. Other model groups of organisms also responded positively to the management applications. Notably, the newly established nectar-rich patches had a significant positive impact on many pollinators, and the thinning of dense stands of trees and shrubs improved plant diversity.

The obtained results are very valuable for capturing changes in communities of organisms associated with changes in habitat management. In the long term, they can be used for continued monitoring both from the perspective of habitat development and local communities. The insights gained can also be applied to other localities of a similar biotopes, which can aid local governments in decision-making for planning applied management and associated biomonitoring efforts.