Green treasures: Investigating the biodiversity potential of equine yards through the presence and quality of landscape features in the Netherlands

continue to be appropriate ecosystem services to horse owners in their efforts to provide horses with management systems that safeguard their health and welfare [24, 26–28]. The Netherlands is considered one of the most prolific equestrian nations worldwide. With approximately 450,000 riders and 500,000 horses, equestrianism is considered one of the most popular sports [29]. Previous research suggested that these horses are kept at approximately 81,000 locations [30], of which 10,000 are businesses such as livery yards, riding schools, as well as breeding and training stables. The rest are likely to be private locations where horses are kept either at home, or on privately rented land. Considering that the Netherlands is con- fronted with a combination of spatial restrictions, a prominent agricultural sector and strin- gent EU requirements regarding the protection and restoration of biodiversity resources [31, 32], the equine sector may likely play an important role in the preservation and improvement of land-based biodiversity levels through the integration of LFs. In order to determine the biodiversity potential of equine land use it is important to gain an overview of the prevalence, types and area coverage of LFs across different types of equine yards. Increasingly, studies aimed at collecting environmental data with extensive geographical coverage rely on the involvement of volunteers to gather data [33–35]. Considering the logisti- cal, organisational, and financial challenges in conducting a traditional data collection study

across the different types of equine yards, such a citizen science approach was considered an effective way of gathering data. Therefore, the aim of the current study was to gauge the pres- ence, frequency and geometric properties of LFs on private and commercial equine yards, including in relation to property size, across the Netherlands, drawing on the active participa- tion of yard owners. Method Survey design In order to engage as many yard owners as possible across the Netherlands, a cross-sectional study design was used, targeting Dutch private horse owners who kept their horses at home, as well as commercial equine yard owners who managed their own land. The survey included a total of 152 questions in Dutch and was designed in the online survey tool Survey Monkey. In the first part, participants were asked to provide information on whether the yard was privately or commercially owned, the general geographic location (i.e. region), size of the property, designation (i.e. type of agricultural activities allowed); soil type and number of horses kept on the property. For the second part, participants were asked to provide informa- tion on the presence and, where applicable, size of landscape features (LFs) present, as well as other biodiversity enhancing attributes (Table 1). The LFs included in the survey were deter- mined according to guidelines from Stichting Part-Ner, Nature Certification, and cross- checked with the EU Functional Landscape Feature classes according to Czu´cz, Baruth, Terres, et al. [10] (Table 1). Participants

Participants were recruited via social media by posting the link to the survey on social media channels from Van Hall Larenstein (VHL), relevant equestrian partners and researchers’ per- sonal accounts. Further distribution relied on a snowball effect for maximum impact. Partici- pation was voluntary and participants were asked to actively consent to take part in the study. No personal information was included as part of the data collection, but participants could leave their email address if they were interested in participating in future research relating to biodiversity in equine yards. The study was conducted in line with the Dutch Code of Conduct for Research Integrity. PLOS ONE Biodiversity potential of equine yards through landscape features PLOS ONE | https://doi.org/10.1371/journal.pone.0301168 April 11, 2024 3 / 16