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| Last Updated:: 23/04/2013

Ecology

 

          Ecology is the scientific study of interactions of organisms with one another and with the physical and chemical environment. "Ecology" comes from the Greek words oikos, meaning "house," and logos, meaning "logic" or "knowledge." The term was coined by German zoologist Ernst Haeckel in 1870. Although 'ecology' includes the study of environmental problems such as pollution, the science of ecology mainly involves research on the natural world from many viewpoints, using many techniques. Modern ecology relies heavily on experiments, both in laboratory and in field settings. These techniques have proved useful in testing ecological theories, and in arriving at practical decisions concerning the management of natural resources.

          An understanding of ecology is essential for the survival of the human species. Our populations are increasing rapidly, all around the world, and we are in grave danger of outstripping the earth’s ability to supply the resources that we need for our long-term survival. Furthermore, social, economic and political factors often influence the short-term distribution of resources needed by a specific human population. An understanding of ecological principles can help us understand the global and regional consequences of competition among humans for the scarce natural resources that support us. Ecology is a science that contributes considerably to our understanding of evolution, including our own evolution as a species. All evolutionary change takes place in response to ecological interactions that operate on the population, community, ecosystem, biome and biosphere levels. Studies conducted within the scientific discipline of ecology may therefore focus on one or more different levels: on populations of a single species, on an interacting community involving populations of many species, on the movement of matter and energy through a community within and ecosystem, on large scale processes within a biome, or on global patterns within the biosphere.


Wetlands of Kerala

          Wetlands are ecotones or transitional zones that occupy an intermediate position between dry land and open water. Wetland ecosystems are dominated by the influence of water, they possess characteristics of both terrestrial and aquatic ecosystems and properties that are uniquely of their own. Wetlands support a wide array of flora and fauna and deliver many ecological, climatic and societal functions. Scientists often refer to wetlands as the "kidneys" of the earth and forests as the "lungs" of the earth. India by virtue of its extensive geographical stretch and varied terrain and climate, supports a rich diversity of inland and coastal wetlands.

 

          Kerala is well known for its wetlands. These wetlands provided livelihood to the residents in the area in the forms of agricultural produce, fish, fuel, fiber, fodder, and a host of other day-to-day necessities. As long as human intervention remained minimal, the ecosystem, through its allencompassing balancing nature, was self-cleansing. But the development demands that determine the choice of the paths upset the natural harmony. Infrastructure development in the form of roads, railways, and other lines of communication fragmented the contiguity of the wetlands, and destroyed extensive tracts of coastal vegetation thereby upsetting the entire complex ecology; rapid urbanisation encroached into the rich and luxuriant mangrove forests, while industrial development not only caused pollution but prevented any regeneration possibilities as well; modern shrimp farms brought in the final onslaught - the irreversible destruction of wetlands. Coastal Kerala with its high density of population cannot bear such onslaughts any longer. The degradation of the wetlands of Kerala is not an isolated event. Worldwide, wetlands are in peril. They are either being polluted, drained or filled up to give way for development. The rate of wetland loss has accelerated in recent years. Thus the wetlands are now the most threatened ecosystems of our planet.

  

 

Agro-Ecological Zones of Kerala

          Four parameters that together evolve distinct agronomic environments wherein a distinct cropping pattern flourishes are altitude, rainfall pattern, soil type and topography. The parameters and their levels used for delineating agro-climatic zones are summarized below. The levels of each parameter are broadly determined to avoid complexity in the process of land evaluation. In reality, there can be several more levels for each parameter (For example, there are 38 soil associations identified in Kerala, at 1:250,000 scale).

 

Altitude: Altitudinal variations influence the temperature regime. High altitude generates temperate climatic conditions in a tropical area like Kerala. Sizeable areas in the high ranges of Idukki and  Wayanad districts fall under this category, even though high altitude areas are found all along the Western Ghats. The low altitude region, endowed with humid tropical climate is spread over the entire length of the state.

Rainfall: The State is relatively rich in rainfall endowment; with an annual precipitation around 2600 mm. Ninety percent of this precipitation is during the two monsoons, June to August (southwest) and October to November (northeast). About 60% of annual rainfall is received during southwest monsoon period and about 30% during northeast monsoon. From December to March there is very little rainfall, but the occasional rainfall during this period is a very critical requirement for cultivation as we still depend upon rainfall for raising many of the crops. The spread of rainfall is relatively better with 6-7 months having rainfall above or nearly around the monthly average. The quantum of annual precipitation is concentrated around lesser periods towards the northern part of the state while it is spread over longer periods in the southern parts. The co-efficient of variation of the annual rainfall is below 20% and hence, agriculture is expected to flourish under relatively stable conditions. However coefficient of variation of monthly rainfall is high. As a result, stability in production can be ensured only with the support of irrigation at least for most of the major crops so as to increase their production and productivity. The state was divided into two halves namely the areas south and north of lION latitude (approximately south and north of Thrissur) with rainfall pattern i and II respectively. The southern region is having relatively well distributed rainfall and June maxima for SW monsoon while the northern region has relatively ill distributed rainfall and July maxima for SW monsoon.

Soil Types: Soil type is the third factor for distinguishing specific zones. The major group under the soils of Kerala is laterite and its variations. In the traditional midland region the dominant soil type is typical laterite with the B-horizon present. The areas skirting the Western Ghat and the high ranges which together form the traditional highland region has lateritic soil where the B-horizon is absent. Red loam is found in the southern most tip of the state. All these variability constitute distinct homogeneous agro-ecological zones, though the rainfall pattern is the same. Distinct zones have been identified based on special soil types such as riverbank alluvium, peaty soil (kari) as in Kuttanad and 'sandy soils, though the rainfall pattern and topographic models are the same. In the coastal area, the texture of the soil- especially of the garden lands is considered as a distinguishing feature in identifying two separate zones one with sandy loam and the other with sandy soil. The soil characteristics of the paddy land such as peaty (kari) and saline soils (pokkali) have also been associated in delineating the zones.

Topography: Areas having similar rainfall pattern and soil type are further delineated into zones based on topographical features. For instances, the midland region north of II _ latitude has a common rainfall pattern and the soil is of typical laterite with B-horizon. It is further delineated into two zones based on the differences in topography with one zone having topographic Model II-b and the other Model II-c. Similarly the midland region south of II  "N has been delineated into two zones based on the differences in topographic features as models II-a and II-b.

            Following the above approach and using a matrix built upon altitude, rainfall, soil and topography, the state has been delineated into thirteen agro-climatic zones. Block Panchayat has been taken as the unit for purposes of delineation. All the Blocks, Municipalities and Corporations have been grouped into appropriate agro-ecological zones. Whenever a Block or Municipality was found to fall in more than one agro-climatic zone, it was assigned to that zone which has the largest area. Though 13 agro-climatic zones have been identified, no Block was assigned to one zone viz. the Riverbank alluvium as it is found scattered in several blocks. This zone is found generally all along the banks of the major rivers. It is found relatively extensively in the lower basins of the Periyar and Pampa river systems. Further, such alluvium deposits are generally found in the paddy fields that form the valley portions of the undulating landscape, which is interspersed with mildly sloping hills. The principal characteristics of each zone are summarized.. Each of the zones identified is assigned a popular name. Many of them are currently in vogue and are associated with areas having singular agro-climatic features and cropping patterns.

 

Parameters for identifying agro-ecological zones

 

No.

Zones

Altitude type

Rainfall pattern

Topography model

Soil type

I

Onattukara

I

I

I

Sandy loam

II

Coastal Sandy

I

I

I

Sandy loam

III

Southern midlands

I

I

III

Laterite without B-horizon

IV

Central midlands

I

I & II

IIa

Laterite

V

Northern midlands

I

II

IIb

Laterite

VI

Malappuram type

I

II

IIc

Laterite

VI

Malayoram

I

I

IIII

Laterite without B

VIII

Palakkad plains

I

II

II

Red loam

IX

Red loam

I

I

III

Red loam

X

Chittoor black soil

I

II

IIa

Black

 

black soil

 

 

 

soil

XI

Kuttanad

I

I

I

Peat (kari)

XII

Riverbank alluvium

I

I

I

Alluvium

XIIIII

High ranges

II

I& II

III

Red loam

 

Distribution  of agro-ecological zones of Kerala

 

No.

Zones

Distribution

I

Onattukara

Quilon ©, Chavara, Karunagappally, Ochira, Kayamkulam (M), Mavelikkara, Mavelikkara (M), Muthukulam1, Haripad2

II

Coastal Sandy

Ambalapuzha2, Alleppey (M)2, Aryad3, Kanjikuzhy3, Cherthalai(M), Pattanakad3, Thykkattussery3, Vaikom (M), Vaikom3, Vyttila4, Edappally4, Palluruthy4, Kochi ©4, Vypeen4, Parur4, Parur (M), Kodungallur, Thalikkulam, Mathilakom, Chavakkad, Andathode5, Ponnani5

III

Southern midlands

Trivandrum ©, Trivandrum Rural, Kazhakkuttam, Chirayinkeezh, Attingal (M), Varkala, Kilimannoor, Ethikkara, Mukhathala, Anchalummude, Chadayamangalam, Kottarakkara, Vettikkavala, Chittumala, Sasthamkotta, Elanthur, Pandalam, Kulanada, Bharanikkavu, Chengannur7, Koippuram7, Thiruvalla (M)7, Mallappilly7, Changanacherry (M), Madappally2, Pallom, Kottayam (M), Ettumannur2, Kaduthurithy

IV

Central midlands

Pampakuda, Vadavucode, Koovappady, Perumbavoor (M), Vazhakkulam, Aluva (M), Alangad7, Parakadavu7, Angamaly, Mulanthuruthy, Mala, Vellangallur5, Irinjalakkuda (M), Irinjalakkuda5, Cherpu5, Anthikkad5, Thrissur ©, Puzhakkal5, Mullassery, Kunnamkulam (M), Chowannur, Trithala, Pattambi, Ottappalam.

V

Northern midlands

Pandalayani8, Balusseri, Perambra, Meladi, Vadakara (M), Thodannur, Kunnummel, Tuneri, Badagara, Thalassery6, Thalassery(M), Kuthuparamba, Edakkad, Cannanore (M), Irikkur, Cannanore6, Taliparamba, Payyannur

VI

Malappuram type

Tirur, Kuttipuram, Tanur, Tirurangadi, Vengara, Malappuram, Manjeri, Kondotty, Kozhikode8, Kozhikode ©, Chevayur, Kunnamangalam, Koduvally, Nileshwar8, Kanhangad9, Kasargod9, Manjeshwar9

VI

Malayoram

Perumkadavila, Vellanad, Nedumangad, Vamanapuram, Anchal, Pathanapuram, Parakode, Konni, Ranni, Vazhoor, Kanjirappally, Pampady, Erattupetta, Lalam, Pala (M), Uzhavoor, Thodupuzha, Elamdesam, Muvattupuzha, Muvattupuzha(M), Kothamangalam, Chalakudy7, Kodakara7, Ollukkara, Pazhayannur, Mannarkkad, Sreekrishnapuram, Perinthalmanna, Mankada, Vandur

VIII

Palakkad plains

Alathur, Palakkad, Palakkad (M), Kuzhalmannam, Nemmara10

IX

Red loam

Nemom, Neyyattinkara (M), Athiyannur, Parassala

X

Chittoor black soil

Chittur, Kollengode

XI

Kuttanad

Chambakulam, Veliyanad, Pulikeezhu7

XII

Riverbank alluvium

Distributed as narrow stretches in the river banks all over Kerala

XIIIII

High ranges

Arudai, Devikulam, Attapadi, Kalpetta, Sultan Battery, Mananthavady

M-Municipality; ©-Corporation; 1-Kayal land; 2-Kuttanad; 3-Kariland; 4-Pokkali land; 5-Kole land; 6-Kaippad lands; 7-River bank alluvium; 8-Brown sands; 9-Sandy; 10-High ranges

 

The Economics of Ecosystems and Biodiversity

 

Source: KISSAN KERALA