Impacts of Anthropogenic activities on the ecological integrity of Nairobi City Park, kenya

Abstract

The effects of human disturbance on the ecosystem processes influence the management of recreational areas and the benefits that can be obtained. Public urban parks provide environmental, economic and social benefits to the urban communities. The Nairobi City Park (NCP) located on 49 ha of land divided into a conserved area of 33 ha and 16 ha recreational area. The park has a high level of biodiversity and provides recreation to the visitors. Currently many changes have occurred within the Park, which have caused a decline in the biodiversity and hence the ecosystem services derived from the resource. This study, therefore endeavored to find out the causes and impact of these change. The study was guided by the following objectives: (i) to determine species composition of herbaceous and woody plants within the NCP, (ii) to measure vegetation cover of the conserved area of NCP, (iii) to assess plant biodiversity within the NCP, (iv) to ascertain trees physical attributes (height, diameter, number of stumps, and debarking) in NCP’s conserved area, (v) determine number of humans who traverse through NCP’s conserved area (vii) to assess the influence of intensity of human activities on the ecological integrity of the park. The study area was stratified into three strata representing different degrees of anthropogenic influences (the outer, middle and the inner core areas). Data on species composition, cover, biodiversity, and physical tree attributes were collected within each strata using ecological methods. Estimate of the number of people visiting the park was averaged from tallies collected over a period of time. The collected data was analysed using descriptive and inferential statistics. The results indicate that: there were 62 plant species divided into 33 families. Species richness varied within the strata, the outer strata had 1066, middle strata had 1195 and the inner strata had 1403. Plant species abundance ranged between 0.19 and 5.12 in the outer stratum, 0.08 to 5.44 in the middle stratum and 0.21 to 9.98 in the inner core stratum. Ground cover was highest (82.8 %) in the inner core area and lowest (51.5 %) in the outer area and medium (70.5 %) in the middle areas. Bare areas an indicator of degradation was highest (37.4 %) in the outer area, followed by (20.2 %) in the middle area and lowest (3.6 %) in the inner core area. Plant diversity (H’) increased from the outer stratum to the inner stratum respectively (H’-1.602 in outer), (H’-1.691 in the middle) and H’-1.702). Tree characteristics varied within the three strata with the outer showing more impact on debarking, cut stumps and young regenerating plants compared with the inner stratum. The number of people traversing the NCP was highest in the outer stratum followed by the middle and finally the inner core stratum, these differences were statistically (p < 0.05) significant. Negative statistical (β = -.918, t = -12.89, p < 0.001) influence of intensity human activities on the ecological integrity were realized. The anthropogenic influences negatively impacted on the ecological integrity of the park and without managerial intervention the park would eventually not be able to provide the ecological services it was meant to provide. The study ends by recommending: educating the visitors to the park on how to use the resources sustainably, park interpretation to enhance learning to visitors, planting adaptable grass and tree species in the degraded areas, sourcing funding from inteinternational organizations dealing with carbon trade to aid in rehabilitating the park.