Abstract

Urban areas, contrary to popular belief, can serve as significant wildlife refugia, a value that needs to be understood and maximised amidst the rampant urbanisation. Indian case studies show that rational biodiversity assessments through amateur naturalists can serve as an efficient tool to monitor and plan for sustainability of urbanisation. Cities harbour between a quarter to half the total biodiversity in their biogeographic region. However, over half the total urban biodiversity is lost in the city core- the most human impacted zone. Further, up to half the total organisms are confined to a few patches of remnant forests, grasslands or wetlands. Such refugia often occur as the university or defense premises, which must be recognised and willfully protected against any landuse changes, so that biodiversity from these source populations can continue to emigrate to other urban sinks such as public parks or home gardens. Complementary bidoversity friendly strategies include plantation of native plants that provide pollen and fruits to birds, insects and mammals, besides serving as larval food of several butterfly species. Native fish may be reintroduced in ponds and rivers, after removing the weeds such as water hyacinth.  

Urbanising Wildlife?

Straying of a leopard (Panthera pardus) or a gaur (Bos gauras) or slender loris (Loris tardigadrus) in cities along the Western Ghats mountains such as Pune or Bangalore makes news. Such straying is commonly blamed on the loss of their natural habitat and consequent flushing out to surrounding areas due to overpopulation. However, it is often ignored that these cities are still surrounded by habitat corridors that facilitate the dispersal of these creatures in and around the city. Such straying of wildlife in urban areas is thought accidental and unwelcome, but it never prompts retrospection as to how much of urban biodiversity is indeed `wild' and how can urban habitats become wildlife-friendly.

Such re-thinking is essential, given the rampant urbanisation, The world will soon be left with an impoverished biota that is able to tolerate direct (e.g. pollution) & indirect (e.g. habitat fragmentation) impacts of urbanisation worldwide- from Amazonia to Australia. What management strategies might maximise the biodiversity in these impacted, fragmented landscapes is the latest & premier research concern globally (Szaro and Johnston, 1996).

Belief goes that that the urban areas are choicest roosts of most well known naturalists but poor habitat for wilderness. But the ushering of the new millennium reveals otherwise, as recent studies at Delhi, Mumbai, Bangalore and Pune show (Ghate et al, 2001). This wisdom has dawned only when urban naturalists chasing wilderness in remote forests and oceans opened their eyes to homestead natural bounty (Dixit et al, 2001, Website: http://www.ranwa.org/punealive).

Delhi, the Indian capital hosts over four hundreds i.e. every one of the three bird species in the subcontinent. Pune urban area shelter between over half the species of higher animals recorded from the whole of Deccan plateau. In part, such high diversity levels can be attributed to location of such cities in transitional biogeographic zones. However, high urban biodiversity is also largely due to the unnaturally high diversity of natural and moreover, artificial habitats (e.g. garbage dumps that attract scavangers) and year-round supply of water (Burton, 1977). Waterbodies are perhaps the most favourite haunts of naturalists in most cities, especially during winter, when alien, migratory birds flock these wetlands.

Observations of soil fauna during dry season along lake periphery

Urban planner's dilemma

Living world has strange combination of discipline and its absence. Various organismic groups differ considerably with respect to their diversity distribution across habitat types and human impact levels. Natualists from Pune tried to unravel this pattern (Table 1). While there is a general decline of diversity along increasing human impact gradient like at the city centres, it is not uniform with all forms of life. Sensitive organisms like the fish or birds lose over two thirds of their species in high human impact zones, while in contrast, stress tolerant groups like ants or butterflies retain two thirds (Utkarsh et al, 2001).

Although urban areas maintain considerable biodiversity, unique or rare species such as eagles and hornbills are often replaced by more stress tolerant species such as crows (Corvus corvus) and mynas (Acridotheres tristis). The conversion of old houses into skyscrapers has often triggered loss of populations of squirrel or snakes or civets. Conversion of old growth wilderness areas for conversion to manicured parks may result in many bush-dwelling or tree-nesting species disappearing, which often goes unnoticed. 

The higher diversity recorded in some moderately or even considerably human impacted zones such as the city heart or home gardens must not mislead one to undervalue the less impacted zones like the hill forests surrounding the city. For, these continue to be the biodiversity source while most urban habitats serve merely as sinks, unable to sustain the diversity on their own. 

For instance, nearly a fifth of the butterfly species at Pune emerge from their food plants confined to the hill forests which also exclusively host over a sixth of the bird species, seldom seen elsewhere in the city campus. Thus, bird or butterfly richness in the city gardens is  difficult without the hill forests. Thus, while development would always demand fresh sacrifices of natural areas, urban planners can involve rational naturalists in evaluating the ecological values of various optional sites as demonstrated above and sacrifice the one with lowest ecological value. 

Insitutionalising wildlife parks

While most cities incidentally and inadvertently shelter wildlife all around, a few Indian cities, such as Mumbai, Chennai, Chandigarh, and Bhopal, even host formal wildlife reserves, cheek by jowl alongside skyscrapers. Cities like Chennai and Mumbai contain important coastal habitats, with mangroves, sea turtle nesting sites, and other interesting flora and fauna. Most cities host regionally important educational institutions, such as universities, that often constitute the largest and/or the last green patches amidst urbanisation. Besides cultivations, such establishments also harbour derelict areas, with remnant natural vegetation such as grassland or thorny bushlands. These vestigeal green patches may lock up to half the total urban organismic species. Such refugia, particularly the the university premises, must be recognised by conservationsts and environment departments; for willful protection against any landuse changes. Conservation of these refugia would ensure that biodiversity from these source populations can continue to diffuse in to other urban sinks such as public parks or home gardens.

Guided nature walk to expose citizens to their natural bounty

Urban avenues and home gardens can act as significant sinks of biodiversity such as butterflies or birds provided suitable trees and even shrubs or climbers an annuals are intentionally and carefully planted, instead of exotic flowers. 

Nature trails to nearby hills during morning can be educative besides healthy

Living barometers

Citizens can do a lot towards the protection of their immediate environment. Delhi's wonderful Ridge forest today survives because of citizen protests and vigilance (see box). Citizens can put pressure on the administration to plant appropriate tree species, or to ensure that biodiversity conservation is an important consideration in urban development plans. An innovative exercise carried out in a number of cities is a tree census, which gives a very good idea of the diversity and number of trees, and changes in these parameters over a period of time. Chennai's turtle nesting sites have long been protected by the famous "turtle walk" initiated by students and young professionals. Calcutta's wetlands at least partially survive because of a number of NGOs, and resistance against concretisation by traditional fisherfolk who depend on them for livelihood. Many small groups have triggered locality specific data literacy. Prakriti Samsad, a birdwatcher's group in Kolkata has been monitoring the bird population in the city and publishing the ongoing changes. Similarly, the NGO Kalpavriksh has carried out monthly bird counts across Delhi for over a decade. Students from Pune University have initiated monthly monitoring of the living wealth of their campus, and the nearby wetland at Pashan. 

Ecorestoration

Many urban administrations have responded positively to citizen's environmental concerns, by declaring protected areas, enacting legislation like Urban Tree Acts, and integrating some biodiversity concerns while making their master plans.In many cities, protection by local authorities, coupled with the vigil by nearby residents, has facilitated regeneration of natural plants and revival of native fauna such as birds and butterflies. Even seasonal puddles formed in these areas, harbour moults of dragonfly nymphs, indicating ongoing colonisation and establishment of even organisms that are highly susceptible to seasonality. Increasing tree cover of suitable species in the Rajnish Park at Pune, may have helped predominantly Western Ghats butterflies such as the Blue Mormon (Papilo polymenstor) seldom seen in the city earlier. 

An understanding of eco-restoration process can help its manipulation and replication in neighbouring areas and even other cities. Besides, such ongoing monitoring can easily detect notable declines in certain species like the sparrows and vultures, being noticed and debated currently. If such sudden population fluctuations are any signal of impending calamity, the purpose of monitoring is served much beyond academic interests.  Such monitoring can even become quite popular, yet cost effective through Internet publicity such as the electronic discussion group of Asian naturalists having thousands of members worldwide nathistory-india@lists.Princeton.EDU

Pre-emptive Environmental Assessments

Notably, such publications based on long term observations might pre-empt the facile environmental impact assessments (EIAs) that are currently mushrooming like a fashion. Unfortunately, environmentalists are not geared with much concrete, scientific data. That scientific data can at time  lead to stringent legal action against environmental hazards is proven in case of pollution at Delhi and Agra. If the recent legal activism takes note of such serious publications, environmental care cannot be easily wished away by the shroudy EIAs. 

These efforts would hopefully generate broader consciousness and social pressure to serve as living indicators of the human habitat. Notable decline in certain species like the sparrows and vultures, being noticed and debated currently, may prove to be a signal of impending calamity. The purpose of monitoring would then be served much beyond academic interests. 

Urban wilderness management is globally relevant as being gradually recognised by the Millennium Ecosystem Assessment project (Ayunse, 1999) launched by the United Nations Development through the World Resources Institute. Living organisms certainly serve as efficient indicators i.e. barometers to scale the human pressure (Patwardhan et al, 2001). Love for nature resides amongst all of us and surfaces often a curiosity and observations about nature, goes the biophilia hypothesis (Wilson, 1984). If these nature observations are maintained as systematic records in an analytical framework for town planning, the ethereal love for nature can be transformed into rational marriage with urban sustainability.

References

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Ayensu et al, 1999. International Ecosystem Assessment. Science. 286: 685-6.

Burton J. A. 1977. Worlds Apart Vol. 1- Nature in the city. Double Day and Co. New York. 

Ghate U., Nalavade S., Bhatt S. 2001 Urban heavans: Nero's fiddle? The Hindu Folio, May 6: 26-29. 

Dixit. A., Nalavade, S. and Utkarsh, G. 2001 Pune urban wilderness: A case of Millennium Ecosystem Assessment in Gole, P. (ed.). Biodiversity profile of an Urban Area. Ecological Society and RANWA, Pune: 8-13.

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Utkarsh, G. Nalavade, S. Patwardhan, A. 2001 Urban wilderness: The case of Pune city, Western India. In Ganeshaiah, K. N., Uma Shanker. R. and Bawa, K. S. (eds.) Tropical Ecosystems: Structure, Diversity and Human Welfare. Oxford & IBH, New Delhi, Calcutta. 689-92. 

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Table 1 Distribution of diversity of organismic groups across urban habitats at Pune.

Note: The land habitat types roughly in the decreasing order of relative human influence include: forest (F), scrub (S), grasslands (G), plantations (P), agriculture (A), habitations (H). The first three habitat types constitute the wilderness (W) zone while the latter three types constitute the impacted (I) zone. The aquatic ecosystem classification remained at a broad level- low (W) and high (I) impact zones. While sensitive groups such as birds lose two-thirds of their taxa in high impact zones, stress tolerant groups such as ants or butterflies retain two-thirds the total diversity even in heavily human impacted zones.