Avian diversity and density estimation of birds of the Indian Institute of Forest Management Campus, Bhopal, India

1 Consultant, Gujarat Tourism Opportunity Limited, Haveli Arcade, Sector 11, Gandhinagar, Gujarat 382011, India Present address: Aasha Villa, Gayatri Park, Kalawad Road, Rajkot, Gujarat 360001, India 2 Project Officer, Foundation for Ecological Security, A-1 Madhuram Park, Near Srinathji Society, Ganesh Crossing, Anand, Gujarat 388001, India Present address: 2548 ‘Om Bhavan’, 4th Crossing, Chandpole Bazaar, Jaipur, Rajasthan 302001, India 3 Senior Project Officer, WWF-India, House No. 30, Datt Garden View, Near Tilhari Sports Club, Jabalpur, Madhya Pradesh 482021, India 1 anjali.aggarwal191989@gmail.com, 2 govindtiwari007@yahoo.co.in, 3 sprih.harsh@gmail.com (corresponding author)


INTRODUCTION
Birds are some of the most prominent species of the Earth's biodiversity and being sensitive to environmental changes they act as key indicators for assessing the status of ecosystem health (Taper et al. 1995;Olechnowski 2009). Assessing the bird diversity of a habitat over time and space is one of the key issues for avian community ecologists. Richness, abundance and community composition are often used by ecologists to understand the diversity of species in their natural occurrence (Magurran 2004).
The bird community structure is affected by changes in vegetation structure either due to natural or any human induced disturbances (Maurer 1981;Wiens 1989;Rahayuninagsih et al. 2007). Talking about disturbances when two such disturbances occur simultaneously or in quick succession they might lead to a compound disturbance that by impacting ecological resilience and recovery (Buna & Wessman 2011;Harvey et al. 2014) may result in ecological surprises (Paine et al. 1998). Wild fire and simultaneous outbreak in insects like bark beetle can be categorized as one such disturbance. Contrary to general belief of this disturbance having a negative impact on the abundance of bird species, many studies have found that bird species were more abundant post fire when compared with burn free areas (Hutt 1999;Kotliar et al. 2002). This also leads to a change in composition of bird species by addition of certain sallying, canopy and bark insectivorous species.
The change in vegetation composition could impact the quality and quantity of habitat for birds in terms of food, water and cover which can further affect the diversity, abundance and distribution of birds (Western & Grimsdell 1979).
In order to prioritize the future conservation of species, understanding the effect of habitat on bird community structure is important (Zakaria et al. 2011). In the long run, the relative value of different habitats and conservation importance of sites can be assessed by investigating the diversity of birds present at those sites (Bensizerara et al. 2013).
Many researchers have already documented the response that avian diversity shows to different vegetation composition structure (MacArthur & MacArthur 1961), and have also demonstrated that avian diversity increases with an enhanced level of vegetation (Wiens 1969).
This study aims to investigate the bird community structure, bird diversity and density at the IIFM campus. An effort has also been made to prepare a checklist of its bird species. In this paper the bird community structure and composition in different habitats of the campus has been documented. The study also demonstrates the change in density and composition of bird species after an outbreak of fire. There are areas in the campus where human disturbances like logging, grazing are being practiced. The study will assess the differences in avian community among these areas and how are they being impacted by them.

Study area
The study was done in the Indian Institute of Forest Management, Bhopal (23.208371 0 N & 77.384417 0 E), from July 2012 to March 2013. The location of the campus, built on a hill surrounded by water on three sides, along with a wide range of climatic conditions that it passes through brings in diverse structure of habitats. The major types of vegetation include grasslands, open scrub forest, dry deciduous forest and bamboo groves. The study was conducted in 12 transects covering an area of 93 hectare campus (Image 1).
For our study, transects were divided into three habitats according to general landscape attributes and vegetation present there. The chief habitat types were: (i) Open scrub comprising mainly grasslands and scarce vegetation of Leucaena leucocephala.
(iii) Urbanized human inhabited areas like the faculty block, academic block and so on.
The details about transects and habitats into which the campus was divided is given in Table 1. These habitats are also structured by different levels of human disturbance varying from activities like logging, cattle grazing, human settlements and presence of domestic dogs.

Bird survey
The bird population was recorded using the belt transect method (Cunningham et al. 2006). During a transect walk, the observer recorded data on the sightings of bird species, number of individuals sighted and perpendicular distance from the line at which the species was sighted. Only those observations lying within 20m of either side of the transect line were recorded. The survey was conducted either during the morning time zone (between 07:00-09:00 hr) or during the evening time zone (between 16:00-18:00 hr) when the dry deciduous was populated with more species

Density estimate during an outbreak of fire in the open scrub habitat
Before the fire took place, the density of birds was found to be 1.35 birds per hectare while after this event the density increased to 8.80 birds per hectare (Table 6). Table 7 shows the density of birds in the fire affected area and in the area unaffected by fire one month after the outbreak of fire. Fire affected area had density of 13.65 birds per hectare while fire unaffected area had density of 6.47 birds per hectare (Table 7).

DISCUSSION
The present study produced a reliable estimate of birds through direct observations on line transects that were repeatedly walked for over a considerable period of time (Anderson 1983;Kumara 2012;Laure 2007).
The campus has a rich variety of strata and guilds owing to its topography and different habitats like water bodies, open scrub area, dry deciduous area and areas of human settlement, which enhanced the diversity of birds.
In terms of bird community structure, it was largely similar in the open scrub and the dry deciduous habitats as compared to that of the urbanized habitat. The open scrub and the dry deciduous shared 38 common species. There were more numbers of ground insectivore in the open scrub than in the dry deciduous. This high number of species was attributed to the forest fire (Raphael et al. 1987;Adeney et al. 2006;Martin et. al 2006) that took place in October, 2012 in the open scrub. It also affected the diversity of the grassland in terms of a reduction in sightings of nightjars and the addition of a whole new feeding guild of ground insectivores. This was the direct result of an increase in the number of insects after the fire (Russell et al. 2009) which led to the arrival of birds like larks-Ashy Crowned Sparrow Lark Eremopterix griseus, Rufous-tailed Lark Ammomanes phoenicura, Oriental Sylark Alauda gulgula, Skykes's Lark Galerida deva, Indian Bushlark Mirafra erythroptera in groups of 10-20, Common Hoopoe Upupa epops, and Pipits-Paddyfield Pipit Anthus rufulus, Tree Pipit Anthus trivialis. The analysis of the data of one month before and one month after the fire showed an increase in density by 6.51 times after the fire took place.
To account for changes in the density due to seasonal variations, the after fire density of two adjacent transects, i.e., one affected by the fire and one not affected by the fire was carried out. Both of these transects were in the grassland area. The data taken into consideration was for the duration of one month after the fire.
The bird density in the fire affected area was 2.11 times greater than the unaffected area for the same duration for the same habitat.
Habitat to a large extent determined the species composition (Fig. 5). Out of the three studied habitats,

CONCLUSION
In the present study we have showed that seasonality along with change in the habitat structure may influence bird assemblage organization over time. The abundant populations of the Jungle Babbler, the Black Drongo and the Red-vented Bulbul shows an increasing urbanization in the vicinity and even inside the campus. An increase in human settlements will cause more danger to avian species. A more eco-friendly urbanization is essential to curb any more negative human interferences in the areas. Further research on appropriate conservation mechanisms and management techniques with the ultimate conservation goal of changing urban environments into species rich ecosystems are required.