Changed avian assemblage of Savitribai Phule Pune University campus in last four decades

Savitribai Phule Pune University is known for its biodiversity in Pune. In the present study, we have analyzed changes which have occurred on the campus and surrounding area over the last 40 years. Of the 90 bird species reported in the campus and Khadki pond in 1976, we failed to notice 34 species in 2018. A major reason for the decline in bird diversity could be changes in the campus habitat from low scrub jungle, fallow lands and grassland to buildings, roads, and exotic plantations. Increase in human settlement surrounding the campus may also be a contributing factor. Replacing exotic plants by indigenous plant species and control of land use can prevent further loss of biodiversity.


PLATINUM OPEN ACCESS
Cities are under the pressure of anthropogenic activities such as the construction of roads, buildings, industries, increased human settlement, and pollution. Most of the cities in the world are established in biodiversity rich regions. As anthropogenic pressure increases in the cities, people start intruding into naturally balanced ecosystems surrounding them. Increase in the human population and anthropogenic activities affect the diversity and structure of biological communities (Vitousek 1994;Maurer 1996). Urbanization causes long term loss of native habitats (Simberloff 1986) and creates human-specific environments (McKinney 2002). Though anthropogenic disturbance is great within in cities, some places such as campuses of educational institutes are comparatively less disturbed and more rich in biodiversity. The biodiversity of many educational institutes is well documented, making them good places to study changes in biodiversity over time. We noticed an increase in anthropogenic activities in the campus of Savitribai Phule Pune University (SPPU) when consultation of previous floral literature for Ganeshkhind (the surrounding region; Varadpande 1973) indicated drastic changes in vegetation. Grasslandscrub vegetation and fallow land in the campus was diminished, replaced with buildings, roads and exotic plantations. Birds are good indicators of biodiversity change due to their sensitivity to environmental changes (Gregory 2006). In this study, we analyzed the impact of vegetation change and anthropogenic activities on avian diversity of Savitribai Phule Pune University campus and Khadki pond.

Data collection
We surveyed the complete area previously sampled by Goel (1976). Bird survey was carried for one and a Image 1. Savitribai Phule Pune University campus and Khadki pond, Pune. half years, from November 2014 to April 2015 and July 2017 to June 2018. Bird survey was carried out in all three seasons (Monsoon, winter, and summer) and the complete study area was surveyed at least once per season. Other than regular surveys, opportunistic birds seen were also considered for preparing a checklist. Bird surveys were carried out by a single observer in the between 07.00h and 11.00h. Birds were observed using binoculars (Olympus 10 × 50X magnification). Audiovisual cues were used for bird identification. For identification of birds, feeding guild and residential status we used field guides of Grimmett et al. (1999), Ali (2002), and Kazmierczak & Perlo (2000). For bird taxonomy and nomenclature, we followed Praveen et al. (2016).

Results
In 1976, Goel listed 91 bird species for the university campus and nearby area of Khadki pond. From this checklist we observed only 56 species in the current survey. Gallus gallus domesticus (Linnaeus, 1758), a domestic fowl, is not listed in the checklist of birds of India prepared by Praveen et al. (2016), thus we considered only 90 bird species from the previous checklist when preparing a new one. In addition to the previous checklist, we found 16 new bird species in the campus, making a total of 106 bird species listed from Savitribai Phule Pune University campus and Khadki J TT pond. All the birds observed are classified into 17 orders and 53 families, of which 56% birds belonged to order Passeriformes (Table 1 & 2). The richness of insectivore, carnivore and omnivore birds has declined more compared to frugivore and granivore birds ( Figure  1, Table 1). The richness of both resident and migratory birds has decreased compared to 1976 ( Figure 2, Table  1).

Discussion
In 1976, 17% of the entire area of university campus was occupied by buildings, roads, and gardens, the major part of rest of the area was thinly wooded low scrub jungle interspersed with various trees (Goel 1976). There were also fallow lands, three patches of trees, flower nursery and citrus garden. But thinly wooded low scrub jungle, fallow lands, flower nursery, citrus garden are no longer found on the campus, where a majority of the total area is covered with buildings, sports complexes, roads and exotic plantations (Image 2). Currently it is noted that there has been increase in buildings, sports complexes, concrete fence and  I-Insectivore | G-Granivore | F-Frugivore | C-Carnivore | O-Omnivore | R-Resident | WM-Winter migratory | SM-Summer migratory | _-Recorded at the study site in 2018 | ×-Not recorded at the study site in 2018. Note: Birds those feed exclusively on insects are classified into insectivore; birds those feed on insects, invertebrates and vertebrates are classified as carnivore. World biodiversity is facing the threat of exotic plants due to increased trade and transport. Exotic plantations in natural habitats gradually displace birds typical to that habitat (Daniels et al. 1990) and support generalist bird species (Zurita et al. 2006). Significantly less arthropod mass is supported by exotic plants compared to a native plantation, and fewer birds prefer exotic plants (Herrera & Dudley 2003;Flanders et al. 2006;Hickman et al. 2006;Ortega et al. 2006). Natural vegetation in the campus is replaced by exotic plants; Dalbergia melanoxylon and Gliricidia sepium are dominant exotic plants in the campus. Gliricidia sepium is known herbicidal plant; it has nematicidal and insecticidal activity (Nazali et al. 2008). Gliricidia sepium could have reduced herb, shrub and grass cover, reduced invertebrate and vertebrate fauna depending on it, and ultimately it might have affected the bird species diversity. Khadki pond was a perennial pond (Goel 1976), now transformed into seasonal pond (Image 3) that has been overtaken by natural vegetation due to blockage of water channels. The pond is surrounded by a plantation of exotic plant species Acacia mearnsii (Australian acacia) and Euclyptus globulus, and because of these changes the number of aquatic bird species has declined in Khadki pond. In addition to the above mentioned disturbances, there has also been a tremendous increase in human settlements in the area surrounding the campus, which might act as a barrier between campus and surrounding hilly regions. Pune is the eighth largest and fastest growing metropolis in India. From 1967 to 1998, area under human settlements in Pune city increased by 2.4 times, while area under agriculture and grasslandscrub decreased by 31% and 39% respectively (Nalavade 2000(Nalavade -2001. In 2000, 40% (60% in 1950) of total Pune urban area was under agriculture, 40% (15% in 1950) under human habitation, 6% (7% in 1950) under forest, 3% (0% in 1950) under plantations (Dixit et al. 2000(Dixit et al. -2001. We also noticed that richness of both resident and migratory birds declined and it is because of the unsuitability of the habitat. Urbanization was the main cause for encroachment of all the natural habitats in Pune urban area and thus bird diversity has declined in all habitat types (Ingalhalikar et al. 2000(Ingalhalikar et al. -2001.
It is, thus, concluded that increased anthropogenic activities in the university campus and surroundings has led to a decrease in bird diversity. Replacing exotic plantation with indigenous plants and restricting anthropogenic activities could prevent further biodiversity loss in the campus. Further studies are needed to check the impact of Gliricidia sepium the most planted exotic plant species on the plateaus in the Pune urban area through urban joint forest management programme, on the native biodiversity on a larger scale.