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

species), while grassland birds were significantly less abundant (six species). Twelve species were present at most study sites, while 13 species were recorded at only one site. The Shannon-Weaver index for plants was significantly higher at mowed sites than at grazed and unmanaged sites (Table 3). Its values also varied among sites, whereby the lowest value was recorded at the G1 site and the C site (0.96 and 0.97, respectively), while the highest value was associated with the G3 site (1.28). In general, no significant differences in the Shan- non-Weaver index for plants were noted between mowed and grazed sites, or for pollinators and birds across any sites, suggesting that there are no consistent differences in diversity within taxa that could potentially be attributed to the adopted management measures. Our investigation based on the total species diversity findings and the analysis of recorded species by site according to management type revealed that the community similarity among G, M, and C sites is small. Among the investigated groups, birds were found to be the least het- erogeneous (with the highest index of community similarity, i.e., above 0.5), while for plants and pollinators this index ranged from 0.25 to 0.5 (Table 4). When similarities at the group level were examined, a clear pattern was established for each group. Specifically, the greatest similarity among plants was noted between G and M, while pollinators were most similar at G and C sites, and M and C emerged as most similar in terms of bird populations. Plant analyses

further revealed that at the G and M sites grassland was the predominant floristic structure, while the C site was characterised by forest degradation. According to the findings related to pollinators, community similarity index is uniform across the entire study area. According to the GLMs, no significant trends can be established for pollinator diversity and habitat parameters. On the other hand, GLM findings related to bird species revealed that their diversity was primarily affected by diversity of plants within the sites and the percentage of trees outside the site boundaries (Table 5). Table 2. Relative cover (%) of each social behaviour type (SBT) for plants found within management practices (G–grazed, M–mowed, and C–control). S–specialists; G–generalists; DT–disturbance-tolerant species; NP–natural pioneers; IAS–invasive alien species. SBT G M C S 7.06 7.82 3.39 G 14.12 25.22 27.12 DT 25.88 24.35 32.20 NP 12.94 10.43 8.47 IAS 5.88 5.22 1.69 https://doi.org/10.1371/journal.pone.0301391.t002 Table 3. Mean values of the Shannon-Weaver index for plants, pollinators, and birds at study sites (G–grazed, M–mowed, and C–control). Site Plants Pollinators Birds G1 0.96 b 0.94 a 0.85 a A G2 1.09 ab AB 0.44 a A 1.91 a G3 1.28 a 0.93 a 1.76 a M1 1.19 ab 0.92 a A 1.75 a M2 1.06 ab A 0.52 a 1.68 a A M3 1.30 a 1.36 a 1.65 a C 0.97 b B 0.70 a A 2.00 a A * Different lowercase letters indicate significant differences between sites (one-way ANOVA; p < 0.05); Different uppercase letters indicate significant differences

between management practices (one-way ANOVA; p < 0.05) https://doi.org/10.1371/journal.pone.0301391.t003 PLOS ONE Effects of habitat management on biodiversity PLOS ONE | https://doi.org/10.1371/journal.pone.0301391 March 28, 2024 9 / 19