Survey of Ecology and Plantation strategy for conservation of White Bellied Sea Eagle

Survey of Ecology and Plantation strategy for conservation of White Bellied Sea Eagle (Haliaeetus leucogaster)

Presentation by Mr.Premsagar Mestri, SEESCAP ,Mahad.

Under the guidance of Dr.Madhuri Pejaver and Rupa Dawane.

Photos by : Ankit Kerkal , Manashree Bapat.

Introduction

The White bellied sea eagle (Haliaeetus leucogaster) are recognised as an indicator species by which to measure biodiversity, environmental integrity and the general health of the ecosystem in a rapidly changing world (Newton 1979).

The selections of favoured habitat and nesting locations of White bellied sea eagle have been recorded.

A decline in the number of sea eagle nests was noticed in the northern part of Raigad.

Surveys have been carried out from 2006 to 2016 along the 106 Km costal stretch of Raigad district in the state of Maharashtra.

Two prominent estuaries located in the northern part of Raigad which acted as attractive nesting locations for the White bellied sea eagle.

These sites were severely affected by the recent industrialization and ship building projects.

Also, new investors increased the productivity of their land by coconut plantation.

This involved cutting down of trees like Tamarind, Banyan, Wild Almond, Mango, Sativa Terminalia, Arjuna, Beheda, Kalam, etc. which had been growing in these locations for many years.

These trees provide ideal locations for nesting since they provided an easy to access area between the coconut trees and were also close to the much needed hunting ground provided by the estuaries.

The Forest department has also been following a program of removing the natural habitat of mangroves and its accompanying undergrowth.

They are replacing it with Casuarina equisetifolia trees which are foreign to the ecosystem.

In the absence of its favoured nesting sites (indigenous tree species like Wild Almond, Palm, Mango, Banyan) ,the White bellied sea eagle has shifted nesting on these exotic trees.

The WBSE nesting requirements are not entirely compatible with this exotic tree.

The naturally occurring slow change that is observed in the habitat as we move from inland towards the coast (tall trees>shorter trees> shrubs and trees>Mangroves>undergrowth with creepers)

Study Area Raigad Coastal Area Coast line distance : 106km Average width of district : 60km We surveyed 5km wide coastal area Temperature range : 22oC to 30oC Mean relative humidity : 80% Geography: Uniformly rocky and shallow beaches Small sandy beaches Estuaries of the more important rivers The mouths of numerous minor streams

Aims and Objectives

To identify the trees on which nesting is preferred by the White bellied sea eagle in Raigad District in the state of Maharashtra.

To study the population status of the White bellied sea eagle To collect data on the nesting site parameters on the basis of: Distance from sea shore Height of nest from ground level To identify threats to the White bellied sea eagle To use the collected data for the repair and restoration of the surrounding ecosystem.

Methodology

We collected information from available literature and other sources

We located nesting sites of the white bellied sea eagle by walking along coastal line of the district during the breeding season (October to January)

We also collected information from local people by showing photographs.

Materials

Camera (Nikon P510)

Binocular (Olympus 10*50)

GPS for location of nesting sites

Google Earth for mapping and measuring distance

Pole method for measuring height

Observation Table Place

Active/Inactive

Distance from Sea Coast (m)

Age (years)

Underi

Active

0

N.A.

Alibag

Active

200

1

Revdanda Sarve ( Old)

Active Inactive

250 5

100 22

Sarve (new)

Active

150

3

Murud (Old)

Inactive

100

N.A.

Murud (Incomplete)

Inactive

50

1

Velas

Active

300

6

Bharadkhol (Old N.L.)

Inactive

2

N.A.

Aaravi

Active

5

22

Valvati

Active

5

25

Shrivardhan (Koliwada) Shrivardhan (Vetal Pakhadi )

Active

5

N.A.

220

15

Harihareshwar

Active

5

N.A.

Active

Distance between two nests Place Underi to Alibag

Distance between 2 nest location(Aerial distance) 7kms

Alibag to Revdanda

13km

Revdanda to Sarve

14km

Sarve to Murud

9km

Murud to Velas

14km

Velas to Bharadkhol

6km

Bharadkhol to Aaravi

4km

Aaravi to Valavti

1km

Valvati to Shrivardhan (koliwada)

2.8km

Shrivardhan (koliwada) to Vetal Pakhadi

723m

Vetal Pakhadi to Harihareshwar

6.51km

Number of nests on tree species

Height of nest from ground level

Observations Mostly the nests along the sea coats Recorded nests: 13 Active nests: 10 Inactive nests: 3 Tree Species Preference: Casuarina (Casurina equistifolia) : 7 Wild almond tree (Sterculia foetida) :3 Mango tree (Mangifera indica) :1 Banyan tree ( Ficus bengalensis) :1 Asian Palm (Borassus flabellifer) : 1

Distance between two consecutive nest: Alibag & Murud Taluka : 10km Shrivardhan Taluka : 5km

Average territory area: 7km Minimum distance observed: 700m Maximum distance observed: 14km

Frequently preferred height for Nesting 40-60ft Minimum Height at Underi: 10ft Maximum Height at Valvati :100ft approximate

Branch preferred for nesting is facing opposite from sea shore

Nests

libag, Asian Palm tree (Borassus flabellifer)

Revdanda, Wild almond Tree (Sterculia foetida)

rve, Casuarina tree (Casuarina equisetifolia)

Sarve, Casuarina tree (Casuarina equisetifolia

Alternate Nesting site

urud(incomplete nest),Casuarina tree (Casuarina equisetifolia)

Velas, Wild Almond Tree (Sterculia foe

aravi, Casuarina tree (Casuarina quisetifolia)

Valvati, Casuarina tree (Casuarina equisetif

Shrivardhan,Wild almond tree (Sterculia foetida)

Result and Discussion Issues facing WBSE: The Northern stretch of the study area i.e. from Alibag to Murud is under the most stress with both the foraging grounds, Dighi and Salavi Creek, experiencing a lot of problems.

Salavi Creek:- The creek sees by-products from a wide variety of processing and manufacturing plants being poured into it.

Boats carrying chemicals are often seen over the creek which leave a lot of turbidity.

Dighi Creek:- Construction of a port which started in 1999 has been extremely detrimental to the health of the ecosystem in and around the creek.

The port building process involved mining and levelling the hills on both sides of the creek and building structures jutting out into the creek.

The effects that these have had on the ecosystem are clearly seen through the Nest distribution in these areas with the average distance between nests in sub-section one (Alibag to Murud) being 12.5Km with the rest of the study area having an average distance between nests of 3.5Km.

the resorts cropping up all along the sea coast, with resorts located in Alibag, Salav, Murud, Diveagar, Shrivardhan and Harihareshwar.

Casurina Estifolia trees were often the alternative that the WBSE selected simply because of the lack of other suitable nesting trees.

The WBSE is often seen taking a longer time to settle down when roosting on a Casurina tree and often change their nest when possible.

Conclusion

The data collected shows that habitat reduction is the most significant threat to the WBSE,this includes a sizable reduction in the number of indigenous tree species which were suitable for its nesting.

The WBSEs shy away from the first sub-section of the study area because of the heavy industrialization and pollution of its feeding grounds.

The palm plantations can reintroduce indigenous trees along the fence lines which wouldn’t affect the palm plantations productivity while also allowing eco-friendlier fences. Trees like Saliva Terminalia would be ideal as they grow vertically upwards. Also they don’t have a large canopy so it won’t affect the sunlight reaching the palm trees. Others that would be useful include wild almond and mango trees.

Absence of proper knowledge of trees and their effects on the habitat around them have led to a steady decline in the quality of nesting habitat.

The forest department should start planting indigenous trees instead of Casurina equistifolia WBSE feels uneasy adopting the Casurina equistifolia trees for nesting purposes because the tree is flimsier and shakes a lot more when the bird lands on it or it experiences gales of wind.

WBSEs are observed to prefer palm plantations for nesting purposes and use the nests for many years so the owners could be trained to protect the nest and keep tourists/workers away from it.

Thank you!

Thank You …!!