Principles for rainforest and grassland restoration in the Anamalai hills

Nature Conservation Foundation Mysore & Vattakanal Conservation Trust, Kodaikanal

November 2006

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Suggested citation:

NCF & VCT (2006). Principles for rainforest and grassland restoration in the Anamalai hills.

Nature Conservation Foundation, Mysore, and Vattakanal Conservation Trust, Kodaikanal.

Contributors:

Nature Conservation Foundation

Divya Mudappa & T. R. Shankar Raman

Vattakanal Conservation Trust

Bob Stewart & Tanya Balcar

Translation (Tamil version):

Dilip Venugopal

Acknowledgements:

We are extremely grateful to M. Ananda Kumar, Manish Chandi, and Nandini Rajamani for

comments and suggestions that helped improve this document. Theodore Baskaran considerably improved the Tamil version and helped translate specific sections, for which

we are thankful. We are also grateful to the plantation companies partnering with NCF on

the rainforest project on the Valparai plateau: Tea Estates India Ltd, Parry Agro Industries

Ltd, Tata Coffee Ltd, and BBTC Ltd. Invaluable support of the Tamil Nadu Forest Department, particularly the Wildlife Warden, Range Officers, and other staff of the Indira

Gandhi Wildlife Sanctuary is also gratefully acknowledged. Our field staff, Dinesh, Sathish, Murthy, and Krishnan, have also contributed immensely to the execution of this project. A

large number of students, volunteers, colleagues, and friends have also helped us over the

years in fieldwork and contributed to our learning from the project.

Financial support:

The rainforest restoration project in the Valparai plateau of the Anamalai hills is a long-term

field initiative of NCF’s research and conservation action currently supported by:

Conservation, Food and Health Foundation, USA

UNDP-GEF Small Grants Programme, India

Barakat, Inc., USA

Ford Foundation, India

We thank the above agencies for enabling the publication of this document and holding

the parallel workshops.

Photographs:

© Divya & Sridhar, Nature Conservation Foundation, Mysore

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CONTENTS

Page

Restoration of tropical rainforest: principles and practice 1

Tropical rainforests: an introduction 1

Restoration: principles and guidelines 3

Rainforest restoration: practical aspects 6

Restoration of shola-grassland ecosystems: Insights from the Palni hills 14

Nursery and aftercare methodology 15

Role of weeds and exotic species 16

Grassland restoration 16

Basic definitions 21

List of Tables

Tree species of mid-elevation rainforests for rainforest restoration plantings 10

Ripe fruit and seed availability of mid-elevation rainforest trees in Anamalai hills 12

Full range of woody species for shola restoration in the Palni Hills 18

Characteristic tree species in rainforests at different altitudes 22

Exotic species to note in the mid- and high-elevation areas of the Anamalai hills 23

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Restoration of tropical rainforest: principles and practice

Divya Mudappa & T. R. Shankar Raman

Nature Conservation Foundation, Mysore

TROPICAL RAINFOREST: AN INTRODUCTION

Among all forest types on Earth, the greatest diversity of living organisms is found in the tropical rainforest. Also called tropical wet evergreen forest, this forest type occurs in those parts around the equator with over 2,000 millimetres of annual rainfall distributed over most of the year. Dry periods with less than 60 millimetres rainfall occur only for a few weeks at most. As a result, there is luxuriant vegetation and most trees remain green year-round.

Trees and woody climbers called lianas dominate the vegetation of a tropical rain forest.

The canopy reaches an average height of 30 metres or more, with some emergent trees nearly 50 metres in height, towering over the others. The tree canopy is dense, allowing <10% of the sunlight from reaching the forest floor. There is a great diversity of herbs, shrubs, ferns, orchids, and plants called epiphytes that grow on top of the other plants. Even tree bark and leaf surfaces are micro-ecosystems that shelter a multitude of smaller plants, fungi, lichens, and mosses. The rich tapestry of vegetation supports a diversity of animals from minute mites and springtails in the soil to elephants and hornbills. The lives of these species are closely linked to form the complex rainforest habitat.

Complexity

The complexity of these ecosystems stems from two reasons. The first is structural complexity: the forest has many layers ranging from subsoil belowground, leaf litter, to above ground layers such as ground vegetation, understorey, mid-storey, canopy, and emergent trees. A second reason is the varied dependence and interactions among the various rainforest organisms. For example, there is competition for light and moisture among plants, mutualisms of pollination and seed dispersal between plants and animals, herbivory and predation.

Dynamics

Individual trees in tropical rainforest may live for hundreds of years and to a human observer

the forest may look the same year after year. Yet, rainforests are dynamic ecosystems. Biologists have documented intricate details of many processes such as the birth and death of rainforest plants, competition among seedlings, fluctuations within years and across years in the patterns of flowering and fruiting, and their corresponding influences on animal populations and movements. In relatively undisturbed rainforest, one major natural dynamic process is what has been called tree fall gap dynamics. Occasionally, large rainforest trees fall, bringing down other nearby vegetation and creating a gap in the dense canopy through which sunlight streams down to the floor. This triggers the germination of pioneer tree species from seeds lying in the soil and stimulates the growth of many rainforest tree seedlings as well. Rapid recovery ensues and in a matter of years, the gap closes again with the growth of evergreen vegetation in the case of undisturbed forests and deep forest interiors.

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Tropical Rainforests of the Western Ghats

Tropical wet evergreen forests in the Western Ghats occur all along the Western parts from

Maharashtra to Kerala. The best rainforests, however, are found in the southern half of the

Ghats. The region south of the Palghat gap (a 30 km-wide break in the mountain range), known as the southern Western Ghats, contains some of the highest peaks and vast stretches of climax evergreen forest types. It also contains much of the plant and animal diversity, particularly endemic species (species not found anywhere else in the world). The Anamalai hills region is particularly special as it contains the entire range of evergreen forest types and its representative species of plants and animals.

Threats

Around the world, tropical rainforests are among the most threatened ecosystems today. Over 100 million hectares are lost or severely degraded every decade due to human-caused

destruction. Clearing for agriculture, plantations, roads, reservoirs, logging for timber, extraction of minor forest produce, invasions by weedy species, grazing, unplanned development and urbanisation are some of the major threats to tropical rainforests today. Besides direct loss of forest cover (deforestation), these have resulted in fragmentation (leaving remnants of forest surrounded by non-forest habitats), and created large areas of secondary forest (second growth or regenerating vegetation in degraded or disturbed areas).

Major rainforest types in the southern Western Ghats

At least five major types of wet evergreen forest or rainforest are found in the Anamalai hills

region depending on elevation above sea level and aspect (eastern versus western slopes of

the main hill range):

1. Plains and low elevation wet evergreen forest

This type is found at elevations below 700 m, particularly on the western side of the Ghats. It

is characterized by tall dipterocarp trees including many endemics: Dipterocarpus indicus and Dipterocarpus bourdilloni, Vateria indica, Hopea ponga. Historically, much of this type has been lost, especially in the plains. Examples exist in areas near Manamboli and Vazhachal.

2. Medium elevation wet evergreen forest

This is the most extensive wet evergreen type in the Anamalai hills today, found at elevations

between 700 m and 1,400 m. It is characterized by tree species such as Cullenia exarillata,

Mesua ferrea, Palaquium ellipticum, and Myristica dactyloides. Much of this rainforest type

occurs as fragments, including on private lands in the Valparai plateau and Nelliampathy hills. Examples of this type can be found at Iyerpadi near Valparai, near Uralikkal-Surulimalai and in near Malakkiparai.

3. Transitional forests with Lauraceae

As we move higher, between 1,400 m and 1,700 m, the above forest type changes to

montane forest through this transitional forest type. This type has many Lauraceae species

such as Persea macrantha, Neolitsea sp. and Litsea sp. An example is Akkamalai forest.

4. Shola forest

The typical shola forest, a kind of stunted montane wet evergreen forest, is found at

elevations above 1,800 m. This type is found only in the hills of the Nilgiris, Anamalais, and

Palnis in the Western Ghats. Characteristic trees include Schefflera racemosa, Michelia

nilagirica, and Prunus ceylanica. Examples are seen in Konalar-Grass Hills and in Eravikulam.

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3

RESTORATION: PRINCIPLES AND GUIDELINES

What is restoration?

Restoration is the process of returning an ecosystem to its original state prior to disturbance or human impact. Ecological restoration is defined as the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed (Society for Ecological Restoration International Science and Policy Working Group 2004).

What is recovery?

In the context of restoration, recovery means the process of returning to similar conditions

as reference sites:

1) The natural structural characteristics of the ecosystem such as multi-layer vegetation, tree

canopy cover, etc.

2) The natural functional attributes and dynamics of the ecosystem such as pollination,

dispersal, decomposition, etc., and

3) The characteristic indigenous species assemblages of the ecosystem, such as the plants,

animals, fungi, etc. found in reference sites.

What are reference sites?

Restoration should always be towards a goal. Reference sites help determine that goal.

Reference sites are sites containing representative examples of the area under restoration as it was prior to human disturbance. They may also be relatively undisturbed sites located in the same environmental setting (e.g., same elevation, rainfall zone, and soil type), which have been subjected to little or no human impacts.

When is restoration necessary?

It is a common misconception that if we strictly protect an area, it will naturally recover because ‘Nature knows best’. This may be true for large areas of little disturbed forests, but we now know that many areas will not recover even after decades of protection. In such areas carefully planned intervention in the form of restoration becomes necessary because:

1) natural recovery of the original vegetation and associated animal communities will not

occur even under strict protection following the removal or curtailment of disturbance

factors,

2) natural recovery may take an enormous amount of time (decades to centuries) unless we

intervene to ‘assist the recovery’ of the degraded site, and

3) meeting specific conservation goals requires the revival of specific sites within a specific

time period.

What kinds of sites need restoration?

Restoration may be necessary in a wide variety of sites such as areas where:

1) there is heavy infestation of weeds, grasses, and vines, choking natural vegetation,

2) the soil seed bank is depleted or lost due to historical disturbance such as fire and grazing,

3) parent trees that can produce seeds are locally extinct, as in isolated fragments,

4) natural forests have been replaced by monoculture timber plantations or cash crops,

5) settlements, plantations, or other land-use existed earlier but are now abandoned,

6) soil nutrient status and symbiotic mycorrhizal fungal populations are lost or reduced,

7) large areas have been cleared or mined with top soil lost, eroded, or depleted, or

8) open areas have been created due to clear-felling, fires, or landslides.