Urban wilderness : The case of Pune city, Western India

Ghate Utkarsh, Sanjeev Nalavade, Ankur Patwardhan *

* Research And Action in Natural Wealth Administration (RANWA), C - 26/1, Ketan Heights, Kothrud, Pune - 411029, Maharashtra, India.
 e-Mail : ranwa@pn3.vsnl.net.in
Corresponding author - ankurpatwardhan@hotmail.com

Key words - habitat diversity, landuse changes, human impact

Over two dozen naturalists, largely college students, from Pune city have published millennial biodiversity assessment (Nalavade, Dixit and Utkarsh, 2000-1). The study area is termed as `Pune Urban Area' measuring about 700 sq and has radius of about 25 km from the city post office. The studied land habitat types roughly in the decreasing orded 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.

Comparison of Pune biota with records of Bangalore and Delhi highlights that Indian cities also host phenomenal levels of biodiversity and few such as Mumbai or Chennai host even wildlife reserves alongside skyscrapers. Table 1 indicates that various organismic groups differ considerably with respect to their diversity distribution across habitat types and human impact levels. Some groups such as butterflies, reptiles and mammals have over almost all their species recorded from wilderness zone while nearly two third of them occur in forests. In contrast, diversity of fungi, herbs and trees seems to be as much or more in impacted habitats than low impact zone. However, notwithstanding the maintenance of considerable species richness amidst the urban habitats, the unique species are even wiped out under human impact, only to be replaced by more tolerant species owing to suitable life attributes like dispersal abilities. 

Table - I

The results confirm the widely known trends of increase in species diversity with moderate disturbance, though severe human influence tends to erode the diversity, except a few stress tolerant species, often having cosmopolitan distribution and wide habitat choice. Further, rather than the total species diversity, human impact critically affects the diversity of unique species like habitat specialists. Another notable trend is lack of tight correlation across organismic groups, in response to similar human influence as reported in the literature (Kunte et al, 1999). For instance, fish species seem to be sensitive to impact levels such as pollution, besides harvest or introduction of exotic species. 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 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. 

Table 2 presents the past and present landscape composition and ongoing changes, based on perceptions, besides records. The most suffered habitat type has perhaps been riverine vegetation especially babul (Acacia nilotica) tree groves along the rivers of Mula and Pawana. Grassland and scrub in the eastern outskirts has also been severely destroyed. Pune city hosts more than one million vehicles, over three-fourth being two-wheelers. The Mumbai-Bangalore bypass constructed recently skirts the city along the western and south-western margin and virtually cut through the Parvati-Panchgaon forest park is now turned in to island. This study brings out its impacts in terms of loss of amphibian or mammal populations.

Table 2 : Habitat Dynamics of Pune urban Area

Our efforts were inspired by a pioneering, amateur effort to compile checklists urban fauna at Bangalore (Karthikeyan, 1999). Later, we chanced upon a more professional endeavour (Anon, 1997). The college/NGO network initiated by IISc along the Western Ghats (Gadgil, 1996 a, Kunte et al, 1999) has also begun emphasising importance of building local assessments and awareness, besides developing the training material. Such monitoring can help better understanding of the ongoing process of ecorestoration around the city. The revival of natural trees or herbs amidst plantations, has triggered colonisation of these new habitats by birds, butterflies etc. Notably, even seasonal puddles, formed in these areas now harbour moults of dragonfly nymphs etc. indicating ongoing colonisation and establishment of even organisms that are highly susceptible to seasonality. Recently increasing tree cover of suitable species in some parks has probably similarly helped predominantly Western Ghats dweller butterflies. 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. 

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 times 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. 

Acknowledgement :- 

Dr. Prakash Gole of Ecological Society greatly encouraged us. Prof. M. Gadgil and the IISc team, including WGBN members who have variously motivated and buttressed these efforts. World wide Fund for Nature- India (WWF-I) had earlier sponsored RANWA ultimately triggering this endeavour. We remain obliged to them all, besides our friends and families that gracefully bore the brunt of our ecological obsession! 

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