Exploring the effects of habitat management on grassland biodiversity: A case study from northern Serbia

abandonment of grassland, afforestation, or conversion into arable land. Consequently, in the late 20th century, grassland ecosystems became habitats of high conservation value [5, 6]. Given the recent focus on biodiversity changes, grassland conservation offers a great oppor- tunity to introduce innovative biodiversity management measures that can be implemented in the timeframe and conditions under which native species have evolved a mechanism to survive [7]. However, their design and implementation requires a comprehensive knowledge of the history of grasslands and their management, as well as its impact on the community composi- tion of different taxa. For example, it has been established that preserved ancient grasslands are highly organised in terms of species composition and show a high degree of stability in relation to small-scale species fluctuations, while secondary grasslands are less resilient and their species pool is thus vulnerable to disturbances and immigration of other species [8–10]. Therefore, the species composition of these habitats is expected to respond differently to affor- estation, and understanding this causality is crucial for the conservation and restoration of grassland biodiversity. Recent studies further highlight the importance of studying and moni- toring different trophic groups, rather than basing management decisions on individual taxa [11–13]. Yet, despite the growing popularity and complexity of biodiversity research, most conservation efforts tend to neglect the role of different land uses in the biodiversity within

these habitats. In recognition of this shortcoming, several authors have proposed development of conservation strategies for grassland working landscapes, i.e., ecosystems that are specifi- cally managed with biological objectives [14, 15]. This proposal is justified, as grasslands play a vital role in providing a diverse range of eco- system services essential for strengthening conservation efforts, actively involving local com- munities. These conservation initiatives encompass various ecosystem services, including biomass production and the provision of food for grazing animals and other herbivores, car- bon storage and sequestration, as well as the creation of habitats for pollinators, migratory and breeding birds, among others [16]. They also highlight the importance of grasslands as a nest- ing and foraging habitat for solitary bees. Since numerous solitary bee species are currently fac- ing threats, existing evidence suggests that generalist and highly mobile species may adapt to habitat loss by expanding their foraging ranges and utilizing alternative habitats and resources within the agricultural landscape [2, 17]. When developing these strategies, however, it is essential to recognise the role of controlled human activities—especially grazing and mowing [18–22] in maintaining the species richness and abundance of many taxa in grasslands [11, 23–25]. Still, extant management policies and conservation measures give precedence to the identification and analysis of rare or threatened

species in protected areas, thus overlooking the fact that, in any process of natural habitat res- toration through succession, it is the species with a broad ecological response that first conquer the habitat and form communities that create the micro-conditions for the specialists to enter. Consequently, their importance as precursors in natural succession processes is rarely exam- ined in scientific studies. This perspective adopted in both research and practice has created the need for decision makers to be actively involved from the beginning of the restoration process and to prioritise the habitat types to be restored and the species that should be returned to their original habitat. To exemplify how this strategy is adopted in practice, we have conducted our investigation in the Pannonian biogeographical region. This region has a complex, long, and documented his- tory of landscape changes and thus provides a suitable site for biodiversity analyses guided by the following aims: (i) to investigate how management measures and habitat heterogeneity impact on grassland biodiversity; (ii) to evaluate the role of grazing and mowing in the restora- tion, development, and heterogeneity of semi-natural grasslands; and (iii) to assess the suitabil- ity of machine learning models for decision-making processes and management programs. PLOS ONE Effects of habitat management on biodiversity PLOS ONE | https://doi.org/10.1371/journal.pone.0301391 March 28, 2024 2 / 19 Funding: This work was supported by the Ministry of Science, Technological Development and

Innovation of the Republic of Serbia [grant number 451-03-66/2024-03/ 200125 & 451-03-65/2024- 03/200125]; Provincial Secretariat for Higher Education and Scientific Research,Autonomous Province of Vojvodina [grant number 142-451- 3485/2023-01]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.