Current Status and Sustainable Management of Bio-diversity in Nilmini Estate Private Ltd., Ihala Millawa, Morawaka
1. Introduction
This report presents an evaluation of the status of bio-diversity in the Nilmini Estate Private Ltd, Ihala Millawa, Morawaka, which is currently under the process of conversion into an organic tea production system. The estate management has applied for the organic certification from SGS Lanka (Pvt) Ltd in 2003. Accordingly, the facility has been placed under 3-year conversion audit by the SGS Lanka (Pvt) Ltd. and this report is aimed at fulfilling a Minor Corrective Action Requests (CAR) suggested in the 12-month conversion audit in 30 July 2004, wherein auditors specifically pointed out the ‘lack of records on bio-diversity with respect to tree species in the organic estate’.
2. Method of Bio-Diversity Assessment
The method used in the bio-diversity assessment included the following steps.
1) All floral species were identified and recorded by a Research Assistant (RA) through a field survey in the estate, particularly in cropped areas
2) Expert advice was sought whenever it found difficult to establish the correct identity of certain species
3) During the same period, all species of fauna observed were recorded
4) Information was collected from the estate staff about the faunal species they have encountered in the premises
5) Historical information of the estate was collected from past documents and residents in the area
It should be noted here that wild patches and uncultivated areas have not been fully explored in the survey and RA has not visually observed all the fauna species reported here. Records on certain wildlife species were based on evidence such as footmarks, reporting of villagers, etc.
3. The Location and Macro Habitat
The Nilmini Estate Private Ltd. is located in Ihala Millawa village of Morawaka, Galle District in the Southern Province of Sri Lanka. The total extent of the Nilmini Estate is 38.8 ha (95.8 Ac). It lines the Dellawa Forest Reserve in its northern boundary and is bordered by two perennial streams in western and eastern boundaries known as ‘Pelwadiya Dola’ and “Horiya Dola’, respectively. The southern boundary of the estate is located at the Ihala Millawa village. The topography of the land rises from the flat terrain in the southern part to a relatively steep area in the northern border.
Morawaka area belongs to the south-western quarter of the wet zone of the country. Sri Lanka is a world biodiversity hot spot and the South-western quarter is the most species-rich area in the country. Besides, the specific location of the estate is in the neighborhood of the Dellawa Forest Reserve, one of the few remaining patches of tropical humid wet evergreen forest (tropical rain forests) in the country. The Dellawa forest is connected to the world-famous Sinharaja World Heritage site and is considered a part of the ‘Sinharaja Adaviya (Range)’ before it was fragmented in too few patches due to human intervention. Hence, the Nilmini Estate is located in an ecological zone that is endowed with one of the richest bio-diversity regimes not only in Sri Lanka but in the world as well.
4. Present Land Use and Evolution of the Current Bio-diversity Regime
The present land use of the estate is consisted of about 16 ha (40 acres) of vegetative tea cultivation which led to the fragmentation of natural forest vegetation in the land into few patches of natural vegetation. These forest patches cover a total area of about …. ha. In addition, a small part (…. ha) of the land is covered with open wetland too. These are the main components of present land use in the estate and the rest of the land is allocated for buildings (bungalows, organic tea factories, labor quarters, etc.), roads and other infrastructure needs.
Evidence indicates that the estate had undergone various changes in land use during the recent history which gave rise to the present bio-diversity regime in the land. Historically, this land was covered with rich natural vegetation in the area that had scarcely been disturbed by human interventions. Villagers from the surrounding areas later disturbed the natural vegetation for ‘chena’ cultivation. According to the documentary evidence, the land was first surveyed in 1935. The first major commercial land use in the estate was a rubber plantation that started in 1930. Around 1968, rubber was replaced with a ‘vegetative’ tea cultivation which has been expanded in to around 16 ha (40 acs) of land. Despite these commercial involvements, a significant area that had earlier been disturbed for chena cultivation has grown into forest vegetation with large tree species, again, thus helping to conserve and maintain a substantial bio-diversity regime inside the estate premises. In addition, some disturbed patches contain secondary vegetation that consists of a number of shrub species with high diversity.
5. Species Composition of Bio-diversity Regime in the Estate
The survey has recorded the 120 flora species belonged to the following categories.
- Trees
- Shrubs
- Wines
- Grasses
- Aquatic plants
In addition, observed groups of species of fauna, namely; birds, mammals, and amphibians also were recorded in the survey. The total number of fauna species recorded under the above categories is 23. While these records are not exhaustive, they reflect the richness of the species diversity in the estate to a certain extent. Complete lists of flora and fauna species recorded in the survey are presented in the appendix tables 01 and 02 respectively. Summary descriptions of species groups recorded under each category are given below. A more in-depth investigation covering year-round observation to identify migratory species also will be undertaken in the future.
5. 1 Trees
A total of 51 tree species were reported. A majority of these species are located in non-plantation areas with primary and secondary patches of natural vegetation. A few of them belong to dominant genera (e.g. Dipterocarpus, Shorea) found in tropical rain forests in the surrounding area. In addition, a number of domesticated multi-purpose tree crops also are available. The other important category of tree species is introduced exotic species which are serving as windbreaks and shade trees. Unlike other tree species, these species are mainly located in cropped areas (tea). Some of the species belonged to natural, domesticated and exotic species are high valued timber (see appendix table 01 for their uses).
5. 2 Shrubs
Forty-three shrub species were recorded in the estate. While some of them are economically useful species cultivated by owners of the estate such as tea, coffee, minor export crops and fruit species, there are a significant number of naturally grown species too, which are found mostly in secondary vegetation grown in disturbed patches of lands. Though many of them are considered agricultural weeds some are having medicinal values. Some are used as vegetables while fruits of certain species are edible.
5. 3 Wines
There are 09 species recorded in the survey, which can be categorized as wines. A majority of them are useful species as fruits, vegetables, green leaves, medicinal plants, yams or fruits. Some of them are used for roping purposes also. These species are found in all types of microhabitats in the estate premises.
5. 4 Grasses and herbs
The survey has identified 14 species of grasses and herbs. While a few of them are true grasses, a majority consists of broad leave herbs. Although, many of them are considered as agricultural weeds, some are having medicinal values. Few of them are useful as edible green leaves too. As a category species, it helps to achieve certain ecological services such as providing ground cover to minimize erosion, being useful in the food chain for herbivorous species, etc. Like wine species, grasses and herbs also are found throughout the estate premises, covering all types of microhabitats.
5. 5 Aquatic Plants
This is the type of species least covered in the survey. Only three species have been recorded. The major aquatic habitats in the estate are represented by two streams flowing along the western and eastern borders of the estate. As aquatic habitats these are lotic in nature (flowing water) and some of the trees, shrubs, wines etc. recorded in the survey are found in banks of the streams. Given the relatively sloppy terrain in the estate, very limited space of lentic water (standing water) is available in the estate, naturally. However, the estate management has already taken steps to construct 5-6 pond of standing water and the number of such areas will be increased in the future.
5. 6 Species of Fauna
Observations have spotted 9 mammal species, 9 bird species, 1 amphibian species, and 4 reptile species. These observations represent only a snapshot view of the existing situation and therefore provide a very conservative assessment of the diversity of fauna in the estate.
6. Future Plans to Enhance the Bio-diversity
The master plan of the estate envisages undertaking following activities that can enhance the bio-diversity in the estate.
- Minimizing and complete phasing-out of the application of chemicals that can affect the bio-diversity in a harmful manner
- Intercropping of the main crop tea with coconut and pepper
- Introduction of cover crops and live mulches such as Rotararia, Puraria, Vetivaria (Sevendara), Cymbopogon and Gothamala among tea plants and tea bushes and in open bare land patches
- Cultivation of ¼ acre forest patches consisted of timber species Mahogany, Alastonia, Teak and Sapu
- Establishment windbreaks and shade trees of Accasia, Albesia, and Gliricidia in tea blocks
- Cultivation of Banana in bare land patches
- Growing of Khomba in open places and roadsides and Bamboo along the stream edges
- Establishment of a 1-acre plot of medicinal plants
- Increasing of the grass cover in areas with high soil erosion potential
- Utilization of soil fertility through the addition of compost, green manure, and biogas manure
These activities can be expected to enhance and maintain the bio-diversity resources in the estate in a sustainable manner while helping organic production activities also by providing plant nutrients and organic pesticides, reducing soil erosion and by managing pests and pathogens through natural enemies.