Ecosystem Functional Types Research Articles

Identification of current ecosystem functional types in the Iberian Peninsula

ABSTRACTAim To examine the geographical patterns of the interception of photosynthetically active radiation by vegetation and to describe its spatial heterogeneity through the definition of ecosystem functional types (EFTs) based on the annual dynamics of the Normalized Difference Vegetation Index (NDVI), a spectral index related to carbon gains.Location The Iberian Peninsula.Methods EFTs were derived from three attributes of the NDVI obtained from NOAA/AVHRR sensors: the annual integral (NDVI‐I), as a surrogate of primary production, an integrative indicator of ecosystem functioning; and the intra‐annual relative range (RREL) and month of maximum NDVI (MMAX), which represent key features of seasonality.Results NDVI‐I decreased south‐eastwards. The highest values were observed in the Eurosiberian Region and in the highest Mediterranean ranges. Low values occurred in inner plains, river basins and in the southeast. The Eurosiberian Region and Mediterranean mountains presented the lowest RREL, while Eurosiberian peaks, river basins, inner‐agricultural plains, wetlands and the southeastern part of Iberia presented the highest. Eurosiberian ecosystems showed a summer maximum of NDVI, as did high mountains, wetlands and irrigated areas in the Mediterranean Region. Mediterranean mountains had autumn–early‐winter maxima, while semi‐arid zones, river basins and continental plains had spring maxima. Based on the behaviour in the functional traits, 49 EFTs were defined.Main conclusions The classification, based on only the NDVI dynamics, represents the spatial heterogeneity in ecosystem functioning by means of the interception of radiation by vegetation in the Iberian Peninsula. The patterns of the NDVI attributes may be used as a reference in evaluating the impacts of environmental changes. Iberia had a high spatial variability: except for biophysically impossible combinations (high NDVI‐I and high seasonality), almost any pattern of seasonal dynamics of radiation interception was represented in the Peninsula. The approach used to define EFTs opens the possibility of monitoring and comparing ecosystem functioning through time.

Current Distribution of Ecosystem Functional Types in Temperate South America

We described, classified, and mapped the functional heterogeneity of temperate South America using the seasonal dynamics of the Normalized Difference Vegetation Index (NDVI) from NOAA/AVHRR satellites for a 10-year period. From the seasonal curves of NDVI, we calculated (a) the annual integral (NDVI-1), used as an estimate of the fraction of photosynthetic active radiation absorbed by the canopy and hence of primary production, (b) the relative annual range of NDVI (RREL), and (c) the date of maximum NDVI (MMAX), both of which were used to capture the seasonality of primary production. NDVI-1 decreased gradually from the northeastern part of the study region (southern Brazil and Uruguay) toward the southwest (Patagonia). High precipitation areas dominated by rangelands had higher NDVI-1 and lower RREL values than neighboring areas dominated by crops. The relative annual range of NDVI was maximum for the northern portion of the Argentine pampas (high cover of summer crops) and the subantarctic forests in southern Chile (high cover of deciduous tree species). More than 25% of the area showed an NDVI peak in November. Around 40% of the area presented the maximum NDVI during summer. The pampas showed areas with sharp differences in the timing of the NDVI peak associated with different agricultural systems. In the southern pampas, NDVI peaked early (October–November); whereas in the northeastern pampas, NDVI peaked in late summer (February). We classified temperate South America into 19 ecosystem functional types (EFT). The methodology used to define EFTs has advantages over traditional approaches for land classification that are based on structural features. First, the NDVI traits used have a clear biological meaning. Second, remote-sensing data are available worldwide. Third, the continuous record of satellite data allows for a dynamic characterization of ecosystems and land-cover changes.

Plant Functional Types: Their Relevance to Ecosystem Properties and Global Change

List of contributors Preface Part I: 1. What are functional types and how should we seek them? H. Gitay and I. R. Noble 2. Plant and ecosystem functional types H. H. Shugart Part II: 3. Plant functional types: towards a definition by environmental constraints F. I. Woodward and C. K. Kelly 4. Can we use plant functional types to describe and predict responses to environmental change? R. J. Hobbs 5. Functional types in non-equilibrium ecosystems B. H. Walker 6. Categorizing plant species into functional types M. Westoby and M. Leishman 7. Functional types: testing the concept in Northern England J. P. Grime, J. G. Hodgson, R. Hunt, K. Thopson, G. A. F. Hendry, B. D. Campbell, A. Jalili, S. H. Hillier, S. Diaz and M. J. W. Burke Part III: 8. Plant functional types and ecosystem change in arctic tundras G. R. Shaver, A. E. Giblin, K. J. Nadelhoffer and E. B. Rastetter 9. Functional types for predicting changes in biodiversity: a case study in Cape Fynbos W. J. Bond 10. Defining functional types for models of desertification J. F. Reynolds, R. A. Virginia and W. H. Schlesinger 11. Plant functional types in temperate semi-arid regions O. E. Sala, W. K. Lauenroth and R. A. Golluscio 12. Interactions between demographic and ecosystem processes in a semi-arid and an arid grassland: a challenge for plant functional types W. K. Lauenroth, D. P. Coffin, I. C. Burke and R. A. Virginia 13. Plant functional types in African savannas and grasslands R. J. Scholes, G. Pickett, W. N. Ellery and A. C. Blackmore Part IV: 14. Using plant functional types in a global vegetation model W. Cramer 15. The use of plant functional type classifications to model the global land cover and simulate the interactions between the terrestrial biosphere and the atmosphere R. Leemans Part V: 16. Examining the consequences of classifying species into functional types: a simulation model analysis T. M. Smith 17. Ecosystem function of biodiversity: the basis of the viewpoint H. A. Mooney 18. Defining plant functional types: the end view F. I. Woodward, T. M. Smith and H. H. Shugart Index.