Surveys were conducted in public parks in Berlin, Germany, and Salzburg, Austria. These two cities vary greatly in size and population as well as in surrounding landscape and therefore provide different conditions to test the method.
Berlin is the largest German city (89 174 ha) with more than 3.5 million inhabitants. About 14 % of the city area is public green, 18 % forest, and 7 % water bodies (Senatsverwaltung für Stadtentwicklung und Umwelt 2012). We survey four small parks situated in central dense built-up districts. The Köllnischer Park (KP) is the smallest green space (about 1 ha) in our analysis. It is located near the Spree River and contains some historical buildings. The Engelbecken (EB) is part of the green corridor Luisenstädtischer Kanal, a former canal, and therefore is lower than the surrounding area. Its main feature is a large rectangular water basin. It is protected under historic preservation laws. The Mariannenplatz with its adjacent green space (MP, ca. 8 ha) is part of an intra-urban green corridor. The Carl-Herz-Ufer (CHU, 1.8 ha) is a narrow park accompanying an urban canal.
Salzburg, the fourth-largest city in Austria (150 000 inhabitants) is located at the Alps’ northern fringe. Its administrative area covers 6567 ha, about 58 % is green and blue (Magistrat der Stadt Salzburg 2012). Green areas (including agricultural land and forests) are legally protected. The two parks selected, Lehner Park (LP) and Hans-Donnenberg-Park (DP), differ in size, structural diversity, and the built-up density of the surrounding urban landscape. The DP (7 ha) is located within a less densely built-up residential area. It was built around 1965 as the extension of an old garden and a tree nursery and is partially surrounded by areas used for urban agriculture and recreational purposes. The LP (3 ha) is located within Salzburg’s most densely built-up district, next to the Salzach River and its accompanying walk- and bikeway.
The parks in the two cities are differently sized. While the selected parks in Berlin are rather small (1–2 ha except the Mariannenplatz with its adjacent green space), the two parks in Salzburg are comparatively large (3–7 ha). The selection of differently sized parks is based on the assumption that larger parks may be more used by residents than smaller parks (Schipperijn et al. 2010) because of the higher structural diversity commonly found in larger parks. We will also refer to the issue of park size in the discussion of the results.
Mapping Tool for Urban Parks’ Multi-dimensional Structural Diversity
For urban parks, instruments to audit recreational facilities for physical activities have been developed. Some instruments focus on condition and maintenance (e.g., Cavnar et al. 2004); others on the multitude (e.g., Giles-Corti et al. 2005). Saelens et al. (2006) developed a comprehensive instrument (EAPRS) for the assessment of public recreation spaces with an emphasis on the functionality of physical elements for active use that was also used repeatedly (e.g., Kaczynski et al. 2008; Van Dyck et al. 2013). However, most instruments regard the facilities for physical activities only, thus overlooking biotic and abiotic conditions, aspects that may promote other recreation forms. In contrast, the assessment of landscape’s nature-related diversity for its adequacy for recreation (e.g., V-value-method by Kiemstedt 1967; Zube et al. 1975) is not adaptable to urban parks because it does not incorporate man-made infrastructure.
In contrast to these instruments, we developed a mapping tool referring to urban parks’ multi-dimensional structural diversity defined as diversity which includes biotic features, abiotic site conditions, and infrastructure facilities. We assumed that each of these three dimensions affects park visitors’ evaluation and activities. Instead of focusing on single element such as species, we used a structural level regarding visually dominant features such as meadows, lawns, and groups and rows of trees. There are two reasons for choosing this structural level: it is easy to apply and enables the comparison of different parks in different ecological zones. In addition, people generally have poor species identification skills (Dallimer et al. 2012), and we assumed that they perceive biotic features on a more structural level.
Figure 1 visualizes the conceptual approach of multi-dimensional structural diversity. Each of the dimensions is separated into two main categories; for example, for the dimension biotic features the categories are “tree/forest aspects” and “ground vegetation”, each including various elements (see also Table 1). In the subdivisions, we tried to reach the corresponding level of detail for all three dimensions. The selection of elements was based on a comprehensive literature review on park research and mapping instruments (e.g., Hemphill et al. 2004; Cavnar et al. 2004; Giles-Corti et al. 2005; Saelens et al. 2006), on guidelines for urban biotope mapping used in Germany (e.g., Senckenberg 2007) as well as on our former experiences in park analysis and mapping (Rall and Haase 2011). “Biotic features” contain tree/forest aspects and ground vegetation in respect to both (semi-)natural as well as ornamental vegetation. The first category includes solitary trees as well as group/row of trees taking into account the age/size. We considered also whether the average of the tree species diversity is more than five species on half a hectare. Other elements are hedge, bush, and natural-like, dense wooded area with underbrush. In the category “ground vegetation”, one can note whether there is diverse spontaneous ground vegetation such as herbs or tree seedlings as well as diversity at the water’s edge regarding wetland plants. Further elements are grassed areas of extensive use and management (meadow), lawns with intensive management and use (e.g., for ball games or sunbathing), and flowerbeds.
The second dimension—abiotic site conditions—refers to the category of natural or man-made water elements such as water basin, fountain, natural or near-natural lake or pond, and flowing watercourse. In addition, we regarded whether there is a visually dominant water element in the park neighborhood and whether the given water elements are directly accessible. The category “topography” includes the elements hill or knoll, slope, artificial surface lowering or elevation (“stairs”), and dominant stone or rock formation. Here, the quality of view from the park onto the surroundings is also included. Finally, the third dimension is infrastructure, which defines park facilities for physical active recreation, as well as amenities and facilities for physical passive relaxation. Elements for exercise are distinct bicycle paths within the park, designated athletic field (e.g., with goals), street-/basketball court, and ping-pong table. We also include playground and dog park. Mapped amenities and facilities for passive relaxation include anything constructed for sitting; table, shelter, and pavilion for picnics; historic, artistic, or educational landmark; animal enclosure or petting zoo; any kind of gastronomy; drinking fountain; public restroom. We also consider whether the main paths are lighted.
Mapping and Evaluation of Structural Diversity
Two skilled collaborators mapped the parks in September 2013. They recorded only the presence of the particular property or component, not the number or quality. Therefore, a park with several football fields does not differ from a park with only one. In addition, they recorded components according to their visual dominance. That means that, for example, one young solitary tree standing somewhere off site has not been counted as it has no influence on the visual ensemble or characteristic of the park.
We calculated a coefficient using a simple additive procedure of all assessed characteristics and components. Values were then normalized by the total number of possible elements of each sub-category to make the results comparable. Finally, the mean value of the two sub-categories is shown as the value for total structural diversity in the biotic elements, abiotic site conditions, and infrastructure elements. A calculation example is given in Table 1.
Questionnaire Surveys Assessing Visitors’ Activities and Demands
To identify visitors’ demands, we conducted face-to-face interviews. The interviews were set up after smaller pre-test studies with randomly selected visitors on site as well as with students who we debriefed, that is we posed structured follow-up questions to elicit qualitative information about their interpretations of questions. This helped us to improve the wording for making sure that the questions were eliciting the kinds of responses intended. For example, we selected neutral terms for describing park characteristics (such as “lively going on” instead of “rather crowded situation”). Finally, questionnaires were distributed on both weekends and weekdays during different hours of the day to randomly selected respondents at different park stations. Approached people were first informed about the survey’s objective and answering procedure. Those willing to participate were invited to fill in the questionnaire together with the interviewer (students trained in the procedures and etiquette of conducting the survey). In the parks, the refusal rate varied (20–35 %).
The questionnaire addressed a broad range of issues, but for the purpose of this paper, the analysis is limited to two questions. First, we asked, “What activities are you undertaking in this green space today?” and allow the respondent 3 replies. The second question aimed at the importance of park characteristics for the well-being of visitors. We asked, “How important are the following park characteristics for your well-being today: accessibility, attractive plants and wildlife (biotic features), facilities for relaxation (passive recreation), and facilities for sport and play (active recreation)?” In Salzburg, we also asked about landscape beauty, view, naturalness, and tranquility or lively going on. In Berlin, we additionally asked about shaded areas and proximity to water because of the dominant water elements in some of the parks. We request that interviewees rate the importance they place on these features on a Likert-scale ranging from 1 (not important) to 5 (very important).
Some people refused to participate in the survey due to participation in sports, group activities, or playing with children or because of deficient language skills (immigrants or tourists), so these groups are under-represented in the findings. Therefore, we made additional observation protocols on users’ activities. For this, a quantitative count of the number of different activities was carried out using a standardized observation protocol. To perform the counting, trained observers walked a fixed route (40 min) through the study areas and counted all observed activities.