The effect of visitors’ pressure on the spatial variability of sandy soil in an urban parks in Tel Aviv

Abstract

The effect of visitors' pressure on the spatial variability of soil properties was investigated in three open green areas in Tel Aviv. Six types of micro-environments were chosen: under oak and pine tree canopy with low (OL and PL) and high (OH and PH) visitors' pressure; herbaceous area without visitors' pressure (HE); and resting area under high visitors' pressure (RA). For each micro-environment soil samples were collected from the upper 0-5 cm depth for organic matter content and moisture determination. Before sampling, soil surface compaction and litter biomass were measured. Soil properties were affected by visitors' pressure and by the type of micro-environment. Soil organic matter content and soil moisture proved significantly higher under oak trees at low visitors' pressure. Average litter biomass significantly decreased with increasing visitors' pressure in the tree micro-environments. Average penetration depth decreased significantly with increased visitors' pressure in all micro-environments. In all the cases where averages significantly decreased, variance significantly decreased too, but the coefficient of variations increased. This means that variances changed slower than averages. Changes in averages were accompanied by a change of data population structure, which indicated more soil spatial homogeneity under high visitors' pressure. The data from different intervals of data population of soil properties demonstrated the different sensitivity to visitors' pressure.

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

“…Previously, Gomez-Limon and de Lucio (1995), Sarah and Zhevelev (2007), Zhevelev and Sarah (2008) and Hamberg et al (2010) reported fewer species and an impoverished structure of lower percentage cover and height in areas associated with visitor pressure. Floristic impoverishment pertains mainly to the group of forest plants including ancient forest species and geophytes, which are typical elements for natural forest communities in fertile habitats of oak–lime–hornbeam forests (Matuszkiewicz 2008).…”

“…For particle size distributions between 0.01 and 2,000 μm, the laser diffraction method was applied. Selected soil properties in the upper soil layer (0–10 cm) were, according to Bhuju and Ohsawa (1998), Jim (1998), Haase et al (2000), Sarah and Zhevelev (2007) and Zhevelev and Sarah (2008), important factors affecting plant composition. The results of forest stand availability to off-trail visits are changes in the habitat and their effect on understorey vegetation.…”

“…Many studies have been undertaken to increase our understanding of factors that facilitate a high diversity of native species in urban parks (Hermy and Cornelis 2000; Nakamura et al 2005; Weifeng et al 2006; LaPaixa and Freedman 2010). Trampling (Jim 1998) and other factors associated with the presence of users, referred to as “visitor pressure” (Sarah and Zhevelev 2007; Zhevelev and Sarah 2008), are assumed to be the most important reasons for the decline in species diversity of understory vegetation in parks. Negative effects of trampling on the species diversity of understory plants have been reported for urban habitats (Bhuju and Ohsawa 1998; Sarah and Zhevelev 2007; Zhevelev and Sarah 2008).…”

“…Trampling (Jim 1998) and other factors associated with the presence of users, referred to as “visitor pressure” (Sarah and Zhevelev 2007; Zhevelev and Sarah 2008), are assumed to be the most important reasons for the decline in species diversity of understory vegetation in parks. Negative effects of trampling on the species diversity of understory plants have been reported for urban habitats (Bhuju and Ohsawa 1998; Sarah and Zhevelev 2007; Zhevelev and Sarah 2008). Urban forest stands are usually spatially isolated ecosystems, so these fragments play a key role in biodiversity conservation (Hermy 1994; Hermy et al 1999).…”

“…Understanding these factors is important for the identification and management of park types with the aim of maintaining plant diversity and for determining habitat factors responsible for homogenisation. Due to the high mobility of park users and the resulting mosaic character of understory destruction, it is important to understand this phenomenon both at the ecosystem scale and micro-environments (Sarah and Zhevelev 2007; Zhevelev and Sarah 2008). …”