Agricultural impacts on ecosystem functioning in temperate areas of North and South America

Abstract Land use has a large impact on ecosystem functioning, though evidences of these impacts at the regional scale are scarce. The objective of this paper was to analyze the impacts of agricultural land use on ecosystem functioning (radiation interception and carbon uptake) in temperate areas of North and South America. From land cover maps generated using high-resolution satellite images we selected sites dominated by row crops (RC), small grain crops (SG), pastures (PA), and rangelands (RA) in the Central Plains of USA and the Pampas of Argentina. These two regions share climatic characteristics and the agricultural conditions (crop types) are also very similar. Both areas were originally dominated by temperate grasslands. In these sites we extracted the temporal series of the normalized difference vegetation index (NDVI) from the NOAA satellites for the period 1989–1998 and calculated the mean seasonal NDVI curve for each site. Additionally, we calculated the mean annual NDVI, the maximum NDVI, the date of the year when the max NDVI was recorded and the interannual variability of these three attributes. We compared the mean values of each NDVI-derived attribute between land cover types and between continents. The NDVI seasonal patterns for each land cover type were roughly similar between the Central Plains and the Pampas during the growing season. The largest differences were observed during the winter and spring, when the NDVI of all land cover types in the Central Plains remained at lower values than in the Pampas. This was probably caused by the high annual thermal amplitude in the Central Plains that results in a much more restricted growing season. As a result of these differences in the shape of the NDVI curve, the mean annual NDVI in the Central Plains was lower than in the Pampas for all land cover types but the maximum NDVI did not differ importantly. In both regions, row crops delayed the date of the NDVI peak, small grain crops advanced it and pastures did not change it importantly, compared with rangelands. The interannual variability of the NDVI attributes was higher for small grains than for row crops in both regions. However, small grains crops were consistently more variable between years in the Central Plains than in the Pampas. The opposite occurred with pastures and rangelands, which were more variable in the Pampas than in the Central Plains. This paper confirms and generalizes previous findings that showed important imprints of land use on ecosystem functioning in temperate ecosystems. Our results support the idea that the changes in land cover that have occurred in the Central Plains and the Pampas leaded to similar changes in the way that ecosystems absorb solar radiation and in the patterns of carbon uptake.

[1]  O. Sala,et al.  Regional climatic similarities in the temperate zones of North and South America , 1995 .

[2]  M. Vavra,et al.  Summary: Ecological implications of livestock herbivory in the West. , 1994 .

[3]  Limin Yang,et al.  COMPLETION OF THE 1990S NATIONAL LAND COVER DATA SET FOR THE CONTERMINOUS UNITED STATES FROM LANDSAT THEMATIC MAPPER DATA AND ANCILLARY DATA SOURCES , 2001 .

[4]  José M. Paruelo,et al.  Two decades of Normalized Difference Vegetation Index changes in South America: identifying the imprint of global change , 2004 .

[5]  Joint Agricultural Weather Facility.  Major world crop areas and climatic profiles , 1987 .

[6]  Land‐use impact on ecosystem functioning in eastern Colorado, USA , 2001 .

[7]  H. Mooney,et al.  Human Domination of Earth’s Ecosystems , 1997, Renewable Energy.

[8]  R. Pielke,et al.  Evidence that local land use practices influence regional climate, vegetation, and stream flow patterns in adjacent natural areas , 1998 .

[9]  R. Pielke.  Influence of the spatial distribution of vegetation and soils on the prediction of cumulus Convective rainfall , 2001 .

[10]  N. Ramankutty,et al.  Estimating historical changes in global land cover: Croplands from 1700 to 1992 , 1999 .

[11]  L. Walker,et al.  Ecosystems of Disturbed Ground , 1999 .

[12]  R. O'Neill,et al.  Landscape Ecology Explained@@@Landscape Ecology in Theory and Practice: Pattern and Process , 2001 .

[13]  J. Paruelo,et al.  ANPP ESTIMATES FROM NDVI FOR THE CENTRAL GRASSLAND REGION OF THE UNITED STATES , 1997 .

[14]  José M. Paruelo,et al.  Remote sensing of protected areas to derive baseline vegetation functioning characteristics , 2004 .

[15]  T. Wells,et al.  Natural Grasslands: Introduction and Western Hemisphere. Ecosystems of the Natural World, Vol. 8A. , 1994 .

[16]  R. Myneni,et al.  On the relationship between FAPAR and NDVI , 1994 .

[17]  William K. Lauenroth,et al.  Patterns of Production and Precipitation-Use Efficiency of Winter Wheat and Native Grasslands in the Central Great Plains of the United States , 2000, Ecosystems.

[18]  Roger A. Pielke,et al.  Evidence that local land use practices influence regional climate, vegetation, and stream flow patterns in adjacent natural areas , 1998 .

[19]  S. Verón,et al.  Environmental Controls of Primary Production in Agricultural Systems of the Argentine Pampas , 2002, Ecosystems.

[20]  C. Kucera.  Tall-grass prairie , 1992 .

[21]  C. Tucker,et al.  Satellite estimates of productivity and light use efficiency in United States agriculture, 1982–98 , 2002 .

[22]  J. Wickham,et al.  Thematic accuracy of the 1992 National Land-Cover Data for the western United States , 2004 .

[23]  R. B. Jackson,et al.  Global biodiversity scenarios for the year 2100. , 2000, Science.

[24]  C. Tucker,et al.  Climate-Driven Increases in Global Terrestrial Net Primary Production from 1982 to 1999 , 2003, Science.

[25]  Navin Ramankutty,et al.  Geographic distribution of major crops across the world , 2004 .

[26]  J. Randerson,et al.  Trends in North American net primary productivity derived from satellite observations, 1982–1998 , 2002 .

[27]  José M. Paruelo,et al.  REGIONAL PATTERNS OF NORMALIZED DIFFERENCE VEGETATION INDEX IN NORTH AMERICAN SHRUBLANDS AND GRASSLANDS , 1995 .

[28]  V. Sadras,et al.  Development, growth and yield of late-sown soybean in the southern Pampas , 2003 .

[29]  G.,et al.  Estimation of Total Above-Ground Phytomass Production Using Remotely Sensed Data * , 2002 .

[30]  S. Kalluri,et al.  The Pathfinder AVHRR land data set: An improved coarse resolution data set for terrestrial monitoring , 1994 .

[31]  J. Paruelo,et al.  Land cover classification in the Argentine Pampas using multi-temporal Landsat TM data , 2003 .

[32]  W. Cramer,et al.  The IIASA database for mean monthly values of temperature , 1991 .

[33]  O. Sala,et al.  FUNCTIONAL AND STRUCTURAL CONVERGENCE OF TEMPERATE GRASSLAND AND SHRUBLAND ECOSYSTEMS , 1998 .

[34]  Navin Ramankutty,et al.  Estimating historical changes in land cover:North American croplands from 1850 to 1992 , 1999 .

[35]  José M. Paruelo,et al.  LAND USE IMPACTS ON THE NORMALIZED DIFFERENCE VEGETATION INDEX IN TEMPERATE ARGENTINA , 2003 .

[36]  Gene E. Likens,et al.  Integrated Regional Models , 1993, Springer US.

[37]  Myron P. Gutmann,et al.  The Structure and Function of Ecosystems in the Central North American Grassland Region , 1999 .

[38]  A. Soriano.  Rio de la Plata grasslands , 1992 .