Urban realities: the contribution of residential gardens to the conservation of urban forest remnants

Abstract

Urbanization has destroyed and fragmented previously large areas of habitat. Small remnants that still exist in numerous cities will be unable to sustain many viable wild plant populations if they do not expand into the surrounding urban matrix. Residential gardens form a significant component of urban green space in many cities and therefore could play a role in redressing this problem. Our ecological and social scientific study examined factors influencing the dispersal and regeneration of 12 bird-dispersed native woody species from Riccarton Bush, a 7.8 ha urban forest remnant, into surrounding residential properties in Christchurch, New Zealand. Over 125 years, the reported number of native vascular plant species in the Bush has declined by a third. Some species, particularly Dacrycarpus dacrydioides, the dominant woody species in the Bush, are being dispersed by birds and establishing in residential gardens predominantly within 250 m of the forest margin. These juveniles are not reaching maturity as most gardeners tend to remove all non-planted woody species. This suggests natural potential for regeneration exists but is insufficient without active human intervention. Our survey results show people are supportive of native plants in general but lack knowledge of the species. They are willing to plant locally appropriate woody species if provided with plants, information, and, most importantly, control over the location of plantings. Residential gardens consequently have the potential to play a major role in the conservation of urban biodiversity especially for species suited to the functions and size of gardens.

Managing Tree Diversity: A Comparison of Suburban Development in Two Canadian Cities

“…One study found that residential neighbourhoods developed from forested areas had higher tree species richness and a greater proportion of native species compared to regions developed from prairie land [33]. Researchers have also suggested that the presence of remnant woodland located within or adjacent to residential areas can promote native species establishment and representation within the urban landscape [34,35].…”

“…Home owner attitudes and preferences likely explain the diverse range of planting decisions; many social and economic factors taking place at the property-and neighbourhood-level can influence residential species diversity, such as income [38], education [39], ethnicity and nationality [40], and planting fads [41]. These patterns emphasize the potential for private yards and gardens to contribute to urban forest biodiversity [34,42]. It is thus important to consider how landscape conversion and development history could influence private property trees, particularly in the context of biodiversity management and enhancement.…”

Conservation and Management of the National Bird, Indian Peafowl Pavo cristatus, in Urban Green Areas of Delhi, India

“…Being the largest pheasant, reluctant to fly long distances, averse to humans and fragmentation of habitat is likely to have a detrimental effect on its survival. The selected parks of Delhi are very much disturbed in terms of human presence (Doody, 2010). The early morning and late evening hours should bedisturbance free in the parks so that the peafowl can roam and feed freely.…”

Quantifying the Impact of Different Ways to Delimit Study Areas on the Assessment of Species Diversity of an Urban Forest

“…The urbanization process facilitates the establishment of exotic species through several mechanisms [40]. It reduces the diversity of native species by destroying and fragmenting large areas of habitat [41]. Secondly, exotic species are more likely to adapt to a variety of habitats in the city [42,43].…”