JOSHI et al. 213 Tropical Ecology 43(1): 213-228, 2002 ISSN 0564-3295 © International Society for Tropical Ecology Biome level characterization (BLC) of western India – a geospatial approach P.K. JOSHI, P.S. ROY, S. SINGH, S. AGARWAL & D. YADAV Indian Institute of Remote Sensing (NRSA), Dehradun-248001, India Abstract: Environment is constantly changing as a function of climate and more recently due to human activities. Timely and accurate monitoring of these changes is a difficult task for regional planning and management. Up-to-date information on distribution and rate of changes of any ecosystem are required for a wide variety of applications viz., biome status, en- vironmental, climatic etc. Aerospace technology has been found to be a vital tool for assessment and monitoring of these natural resources. The present study focuses on the potential of IRS 1C WiFS data set for the regional level mapping. The temporal resolution along with the rec- ommended spatial and spectral resolution configures for the assessment of the phenological growth of the vegetation in the terrestrial ecosystems. The utilization of the climatic data along with the biogeographic map is proposed to delineate the biomes in the western Indian subcon- tinent. The product offers the basic input for the eco-physiological processes for studying the land surface interactions and conservation strategies of the arid regions. Resumen: El ambiente está en constante cambio en función del clima y más recientemente como consecuencia de las actividades humanas. El monitoreo preciso y oportuno de estos cam- bios es una tarea difícil para la planeación y el manejo de una región. Se requiere información actualizada sobre la distribución y las tasas de cambio de cualquier ecosistema para una am- plia variedad de aplicaciones, por ejemplo las referentes a la condición del bioma, las ambien- tales, las climáticas, etc. La tecnología aeroespacial es una herramienta vital para la evalua- ción y el seguimiento temporal de estos recursos naturales. El presente estudio se enfoca en el potencial que tienen los datos IRS 1C WiFS para la elaboración de mapas regionales. La re- solución temporal, así como las resoluciones espacial y espectral recomendadas, se configuran para evaluar el crecimiento fenológico de la vegetación en los ecosistemas terrestres. Se pro- pone el uso de datos climáticos junto con el mapa biogeográfico para delimitar los biomas de la porción occidental del subcontinente indio. El producto ofrece los insumos básicos sobre procesos ecofisiológicos para el estudio de las interacciones de la superficie terrestre y las es- trategias de conservación de las regiones áridas. Resumo: O ambiente está mudando constantemente em função do clima e, mais recente- mente, devido às actividades humanas. A monitorização tempestiva, e exacta, destas mudanças é uma tarefa difícil para o planeamento regional e a gestão. Informação actualizada quanto á distribuição e taxas de mudança de qualquer ecossistema é necessária para um conjunto variado de aplicações como sejam o status do bioma, o ambiente, clima, etc.. A tecnologia aeroespacial tem-se mostrado uma ferramenta vital para a avaliação e monitorização destes re- cursos naturais. Este estudo foca o potencial do conjunto de dados obtidos pelo IRS 1C WiFS para o mapeamento a nível regional. A resolução temporal, a par com a resolução espacial e es- pectral recomendada, mostra-se adequada para a avaliação do crescimento fenológico da vege- tação nos ecossistemas terrestres. A utilização dos dados climáticos, juntamente com o mapa biogeográfico, é proposta para o delimitar os biomas na parte ocidental do subcontinente in- Address for Correspondence: P.K. Joshi, Indian Institute of Remote Sensing, 4, Kalidas Road, P.O. Box – 135, Dehradun 248 001, India; Tel: +91-135-744583; Fax: +91-135-741987; e-mail: [email protected] 214 BIOME LEVEL CHARACTERISATION diano. O produto oferece o input básico para o estudo dos processos ecofisiológicos, das in- teracções com a supercície do solo e para as estratégias de conservação das regiões áridas. Key words: Biome level characterization, geospatial approach, green wave, land use/cover, phenology, remote sensing, western India. Introduction general temperature range and precipitation level, we can predict what kind of biological community In nature, there exists a complex of more than is likely to develop on a particular site if that site one community. Communities are never stable, but is free of disturbance for a sufficient time. Biome dynamic. Although a typical community maintains distribution also is influenced by the prevailing itself more or less in equilibrium with the prevail- landforms of an area. Mountains, in particular, ing conditions of the environment, but in nature exert major influences on biological communities. this is hardly true. They are never found perma- Furthermore, with the human population ris- nently in complete balance with their component ing by almost a billion a decade, over the next species or with the physical environment. Envi- three decades at least sustained increases in food ronment always keeps on changing over a period of production is required. According to the projections time due to variations in climate and physiography from the Integrated Model for Assessment of the and the activities of the species of the communities Greenhouse Effect (IMAGE model: Alcamo 1994) themselves. These influences bring about marked and from other analysis, this will result both in changes in the dominants of the existing commu- further conversion of natural ecosystems to agri- nity, which is thus sooner or later replaced by an- culture. Both of these processes always accelerate other community at the same place. This process the release of carbon in the atmosphere. In addi- continues and successive communities develop one tion, as more land is converted to agriculture, after the other over the same area until the termi- there is less area of natural ecosystems available nal final community again becomes more or less to act as carbon-sink; thereby, reducing the poten- stable for a period of time. This occurrence of rela- tial sink strength of the terrestrial biosphere. tively definite sequence of communities over a pe- Changes in the composition and structure of eco- riod of time in the same area is known as Ecologi- systems are driven by a combination of manage- cal Succession. Thereafter, a concept of biome, de- ment practices and changes in climate and atmos- fining as ‘biotic community of geographical extent pheric composition. Hence it makes the assess- characterized by distinctiveness in the life forms of ment of natural resources, changes in the ecosys- the important climax species’ came up (Sharma tem so important to incorporate that new arriving 1997). The biome is not based on the species of policies and strategies would not hinder the bio- plants and animals present but rather on the life spheric activities rather would allow it to flow on forms of the most important plants (i.e. trees, sustainable basis. shrubs, grasses) that give to the landscape its spe- cial character. The chief character of a biome is Present knowledge on biomes depicted by climax communities with their domi- The emergence of biome or ecoregional level nant life forms. Thus a biome is viewed, as a biotic studies is an important step in dealing with diffi- community – a unit larger than a community, con- cult natural resource issues. Ecoregional studies stituting the great regions of the world distin- have distinctive emphasis on interaction between guished on an ecological basis, such as tundra bi- development and conservation, including biological omes, forest biomes, grasslands, deserts etc. and physical resources. The study requires both Temperature and precipitation are among the greater depth of understanding of interactions of most important determinants in biome distribu- humans and ecosystems and more focus on imme- tion along with the topography. If we know the diate social needs. Nevertheless this has grown in JOSHI et al. 215 part by efforts to fill a critical gap in dealing such The wide field of view of the AVHRR provides problems by scaling our understanding from local large-area coverage but involves considerable diffi- to global and how human activities interact with culty in the collection of ground data for valida- the atmosphere. tion. Results of measurement of primary produc- Last decade has been a uniquely productive tion using a harvest technique are described by era for mapping and modeling of earth’s surface Diallo et al. (1991), as the results from the applica- with roots in bioregional sciences, such as biogeog- tion of slightly different methods in Niger that raphy, regional economics of natural resources etc. were suitable for the more extensive and uniform and contemporarily having substantial improve- terrain in the study region (Wylie et al. 1991). ments in computing technologies and also in our These field methods rely maximum on the above- understanding of global and regional systems and ground standing annual vegetation as the estimate the availability of improved earth science data of seasonal production and, therefore, are subject sets. This is clearly articulated by the Interna- to some well-known sources of error (Beadle et al. tional Geosphere Biosphere Program (IGBP) core 1985). However, they are capable of estimating net projects on Biospheric Aspects of the Hydrological production in large areas (in excess of 10 km2) as Cycle (BAHC), Global Change and Terrestrial Eco- is necessary for analysis of the AVHRR data. The systems (GCTE), International Global Atmos- use of AVHRR NDVI data to model regional pri- pheric Chemistry (IGAC), Land-Use and Land mary production is discussed by Prince (1991), in Cover Change (LUCC), Global Analysis, Interpre- which the subject of scale is addressed and rele- tation and Modeling (GAIM), Land-Ocean Interac- vant variables are identified at the regional scale. tions in the Coastal Zone (LOICZ), Past Global Factors that obscure the relationship between the Changes (PAGES) etc.