Effects of visitor pressure on understory vegetation in Warsaw forested parks (Poland)

Abstract

Visitor’s access to understorey vegetation in park forest stands results in the impoverishment of plant species composition and a reduction in habitat quality. The phenomenon of biotic homogenisation is typical in urban landscapes, but it can proceed differently depending on the scale, a detail that has not been observed in previous studies. This research was carried out in seven Warsaw parks (both public and restricted access). Thirty-four forested areas were randomly selected, some subjected to strong visitors’ pressure and some within restricted access areas, free of such impacts. The latter category included woodlands growing in old forest and secondary habitats. Public access to the study areas contributed to the disappearance of some forest species and their replacement by cosmopolitan non-forest species, leading to loss of floristic biodiversity in areas of high ecological importance at the city scale. Some human-induced factors, including soil compaction and changes in soil pH, moisture and capillary volume, were found to cause habitat changes that favoured native non-forest plants. Despite changes in species composition, the taxonomic similarity of understorey vegetation in both categories—public access and restricted access—was comparable. In a distance gradient of measurements taken around selected individual trees, there was found to be significant variation (in light, soil pH and compaction) affecting the quality and quantity of understorey vegetation (including rare species). In conclusion, the protection of rare forest species could be achieved by limiting access to forested areas, particularly in old forest fragments, and we highly recommend its consideration in the proposal of future park restoration plans.

Impact of recreation and tourism on selected soil characteristics in the Lisia Góra Nature Reserve area (south-east Poland)

“…The research sites in the Wi-s³ok Valley were characterised by significantly higher pH values from in the Lisia Góra reserve sites (Table 1). Similarly, as shown by Sikorski et al (2013), soil reaction changed significantly in the objects with pedestrian access. It was found in the research conducted by Zdanowicz and Sk³odowski (2013) that the pH values changed with the distance from the trail as well.…”

“…There were no statistically significant differences between the distances and sites, but the sites in the Wis³ok Valley had higher values of EC (Table 1, 2). As shown by Sikorski et al (2013), salinity changed significantly with a significant impact of tourist pressure in forest park areas, leading to changes in vegetation caused by elimination of some species.…”

“…Ewertowski and Tomczyk, 2007). However, areas that are the most threatened by tourism and recreation are situated within urban borders (Sikorski et al 2013). In each valuable natural area, hiking trails have an important role, especially in protected areas, where the aim is protection of nature, development of tourism, and adaptation to exploration by visitors.…”

What is the role of trees and remnant vegetation in attracting people to urban parks?

“…For example, greater numbers of visitors can introduce weeds, create disturbance, damage vegetation and lead to soil compaction (Bigirimana et al 2011;Hauru et al 2012;Zhou and Chu 2012;Sikorski et al 2013). However, given that urban habitats are highly threatened by degradation and loss, in many instances they may arguably be more valuable for the educational and experiential opportunities they offer than for their contribution to biodiversity conservation.…”

Recreation and terrain effect on the spatial variation of the apparent soil electrical conductivity in an urban park

“…The variability of soil properties of urban parks affects the growth and development of plants (Pregitzer et al, 2016). Significant variation of the soil properties was found in a distance gradient of measurements taken around selected individual trees affecting the quality and quantity of understorey vegetation in park forest stands (Sikorski et al, 2013). The variability of soil properties promotes the maintenance of biodiversity in urban areas (McKinney, 2006).…”