Data are presented from ten central and western North American grasslands, covering six major grasslands types: mountain grassland, northwest bunchgrass, mixed-grass prairie, shortgrass prairie, tallgrass prairie and desert grassland. The experimental design at each location included two replications of ungrazed and grazed treatments. Measured environmental variables included precipitation, temperature and solar radiation, both as annual and growing-season values, along with annual and growing-season actual evapotranspiration. Seasonal above-ground live biomass averaged 94 g/m2 for the ten grasslands (98 g/m2 for ungrazed and 89 g/m2 for grazed treatments). Dead matter averaged about 160 g/m2 for ungrazed and 70 g/m2 for grazed treatments. Total above-ground standing crop (total clipped matter) averaged 203 g/m2 (245 g/m2 ungrazed; 161 g/m2 grazed). In general, the amount of litter corresponded to the total standing crop. The shortgrass prairie had the greatest amount of crown material, and the tallgrass prairie the least (about 275 g/m2 for short- and mixed-grass prairie, cf. 200 g/m2 for tallgrass prairie). Although grazing did not significantly influence crown material, it tended to increase under grazing in mixed and short-grass prairies. Root biomass ranged from 156 g/m2 in the desert grassland to as much as 2000 g/m2 in the mixed-grass prairie. There was an inverse relationship between root biomass dynamics and mean annual temperature; grazing generally resulted in an increase in root/shoot ratios, particularly for the cooler grassalands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. II. Intra-seasonal dynamics in primary producer compartments. Journal of Ecology 66, 547-572.

Summary

Intra-seasonal dynamics are presented for the various above-ground and below-ground primary producer compartments for ten central and western North American grassland sites. Above-ground live biomass followed either a unimodal growth pattern (for cool-season or warm-season communities, in general), or a bimodal pattern (for mixed cool- and warm-season communities). There were no significant differences between grazed and ungrazed treatments in seasonal live biomass, although there was a significant site x treatment interaction. Peak live biomass ranged from 84 to 336 g/m2, and showed a linear increase with growing-season precipitation up to 450 mm, leveling out beyond that. Maximum accumulation rates of live biomass were 0.4-6.5 g/m2/day. The recently-dead compartment showed maximum values soon after attainment of peak live biomass; old-dead, however, was maximal early in the growing season, declining thereafter as material was transferred to the litter compartment. Litter dynamics responded closely to precipitation events, and showed a rather erratic pattern. Root biomass was maximal about midway through the growing season. Grazed treatments typically had a higher peak root biomass in cooler grasslands, whereas no such response was seen in warmer grasslands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. III. Net primary production, turnover and efficiencies of energy capture and water use. Journal of Ecology 66, 573-597.

Summary

Levels of net primary production and efficiencies of energy capture and water use were investigated in six grassland types encompassing ten western North American grasslands. Above-ground net primary productivity (ANPP) ranged from 54 to 523 g/m2/yr; the average for grazed grasslands was 212 g/m2/yr compared with 236 g/m2/yr ungrazed grasslands (P<0.05). There was an apparent linear increase in ANPP with increasing precipitation up to approx. 500 mm/yr. Likewise, ANPP increased linearly with both growing-season and annual actual evapotranspiration (AET). Net root production ranged from 148 to 641 g/m2/yr, and was significantly higher on grazed compared with ungrazed grasslands. In general, root production increased with decreasing long-term mean annual temperature. Total net primary productivity (TNPP) ranged from 225 to 1425 g/m2/yr. Approx. 46% and 58% of the variablility in TNPP was explained by annual precipitation in ungrazed and grazed grasslands, respectively. Warmer grasslands had higher rates of crown turnover, corresponding to increased annual usable incident solar radiation and annual AET. Average rates of root turnover were 0.18, 0.30 and 0.49 for mixed-grass, tallgrass and shortgrass prairies, respectively, with a positive curvilinear relationship between root turnover and total annual usable incident solar radiation. Efficiency of energy capture in TNPP ranged from 0.12% to more than 1.4% for both ungrazed and grazed grasslands - communities dominated by cool-season species appeared to be comparable to or more efficient than warm-season species in terms of energy capture. Grasslands with higher water use efficiencies also had higher efficiency of energy capture - these two functional properties appeared to be positively related.

BADKHYZ

Nechaeva, N. T., S. Ya. Prikhod'ko, and K. F. Shuravin (1971). Harvest formation on the Poa-Carex pastures of the foothills of Central Asia in relation to meteorological conditions (as exemplified by Badkhyz, Turkmenian Republic). In: Biokompleksy Pustyn' i Povyshenie ikh Produktivnosti. Ylym, Ashkhabad. pp. 71-113.

BEACON HILL

Williamson, P. (1976). Above-ground primary production of chalk grassland allowing for leaf death. Journal of Ecology 64, 1059-1075.

Summary

The lifetime of leaves of five common chalkland grasses was determined: depending on species and time of year, this varied from 6 weeks to 6 months. Measurements from marked leaves could be described as a function of temperature and time to 50% death. Applying turnover time to harvest data increased estimates of ANPP to 691 g/m2/yr, more than 2 x the sum of species increments in biomass (332 g/m2/yr), but less than the maximum of biomass plus dead matter (773 g/m2/yr). Results from other studies also show that determination of biomass turnover is necessary for correct estimation of primary production by harvest methods.

CALABOZO

We studied organic matter production in the Trachypogon savanna of the Estacion Biologica de Los Llanos at Calabozo, Venezuela. Biomass was harvested within two study areas, burned and unburned. Above-ground biomass matter production was relatively low (429 g/m2/year), compared with the mean values for tropical savannas after Rodin and Bazilevich (2000 g/m2/year). There is an annual rhythm in production throughout the year, as shown by experiments carried out on irrigated plots. When the wet season was prolonged using irrigation, the maximum live biomass in the burned and irrigated plot was 50% lower, and 67% lower in the unburned and irrigated plot, compared with the maximum biomass at the end of the rainy season for the unburned, non-irrigated plot.

We determined the exchange of atmospheric carbon dioxide and ammonia for Trachypogon savannas using an energy balance approach. Monthly dry matter and nitrogen content of plant parts were used for growth analysis of the community. Net assimilation rate was 0.102-0.127 MJ/m2/day (6.6-7.9 g dry matter/m2/day), similar to mean crop growth rate determined by growth analysis. Apparent efficiency of light energy conversion was low compared with reported values for tropical grasses. During the dry season, the community conserved 71% of the maximum N accumulated in the previous wet season, but 68% of community N content was lost as volatile NH3 during the reproductive phase. N losses were balanced by inputs from precipitation and biological fixation, resulting in a redistribution rather than a loss of nitrogen.

CAÑAS

Summary

Standing crop and above-ground net primary production (ANPP) were determined for a savanna derived by clearing of tropical semi-deciduous forest in the seasonally dry north-western part of Costa Rica. Harvests were made at 4-week intervals of live tissue and litter in vegetation dominated almost exclusively by the perennial grass Hyparrhenia rufa. ANPP was estimated by two methods: from the maximum standing crop which builds up between annual fires, and by summing monthly estimates of production.

CHARLEVILLE

Christie, E. K. (1978). Ecosystem processes in semi-arid grasslands. I. Primary production and water use of two communities possessing different photosynthetic pathways. Australian J. Agricultural Research 29, 773-787.

Summary

Above and below-ground productivity and estimated evapotranspiration rates of a C3 native grassland and a sown C4 buffell grassland community growing on sandy red earth soils were studied over a 12 month period. Resistance to water vapour transfer from leaves of both species was measured in the field and glasshouse. Bufell grass had the highest maximum above-ground growth rate in summer, but the most striking difference between the two communities was its greater root standing crop and production. Above-ground growth rates were very low in winter, with little difference between the communities. Water use efficiency of the C3 community was about 60% of that of the C4 community. Leaf resistance of the latter was greater under conditions of limiting and non-limiting water supply.

Christie, E. K. (1979). Ecosystem processes in semi-arid grasslands. II. Litter production, decomposition and nutrient dynamics. Australian J. Agricultural Research 30, 29-42.

Summary

Changes in tissue concentration and nutrient uptake were studied for a C3 native grassland and a sown C4 buffell grassland. Seasonal patterns of litter production in grazed and ungrazed grasslands are reported. The decline in above-ground biomass growth of both communities over the summer growing season corresponded with simlar trends in N and P uptake. Shoot P concentrations for all perennial grass species were always low. Total N & P absorbed by the buffell grass community was 35% greater than the native grasses. Continued overgrazing led to a reduction in litter and root yield.

COTTONWOOD, CPER

Sims, P. L., J. S. Singh, and W. K. Lauenroth (1978). The structure and function of ten western North American grasslands. I. Abiotic and vegetational characteristics. Journal of Ecology 66, 251-285.

Summary

Data are presented from ten central and western North American grasslands, covering six major grasslands types: mountain grassland, northwest bunchgrass, mixed-grass prairie, shortgrass prairie, tallgrass prairie and desert grassland. The experimental design at each location included two replications of ungrazed and grazed treatments. Measured environmental variables included precipitation, temperature and solar radiation, both as annual and growing-season values, along with annual and growing-season actual evapotranspiration. Seasonal above-ground live biomass averaged 94 g/m2 for the ten grasslands (98 g/m2 for ungrazed and 89 g/m2 for grazed treatments). Dead matter averaged about 160 g/m2 for ungrazed and 70 g/m2 for grazed treatments. Total above-ground standing crop (total clipped matter) averaged 203 g/m2 (245 g/m2 ungrazed; 161 g/m2 grazed). In general, the amount of litter corresponded to the total standing crop. The shortgrass prairie had the greatest amount of crown material, and the tallgrass prairie the least (about 275 g/m2 for short- and mixed-grass prairie, cf. 200 g/m2 for tallgrass prairie). Although grazing did not significantly influence crown material, it tended to increase under grazing in mixed and short-grass prairies. Root biomass ranged from 156 g/m2 in the desert grassland to as much as 2000 g/m2 in the mixed-grass prairie. There was an inverse relationship between root biomass dynamics and mean annual temperature; grazing generally resulted in an increase in root/shoot ratios, particularly for the cooler grassalands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. II. Intra-seasonal dynamics in primary producer compartments. Journal of Ecology 66, 547-572.

Summary

Intra-seasonal dynamics are presented for the various above-ground and below-ground primary producer compartments for ten central and western North American grassland sites. Above-ground live biomass followed either a unimodal growth pattern (for cool-season or warm-season communities, in general), or a bimodal pattern (for mixed cool- and warm-season communities). There were no significant differences between grazed and ungrazed treatments in seasonal live biomass, although there was a significant site x treatment interaction. Peak live biomass ranged from 84 to 336 g/m2, and showed a linear increase with growing-season precipitation up to 450 mm, leveling out beyond that. Maximum accumulation rates of live biomass were 0.4-6.5 g/m2/day. The recently-dead compartment showed maximum values soon after attainment of peak live biomass; old-dead, however, was maximal early in the growing season, declining thereafter as material was transferred to the litter compartment. Litter dynamics responded closely to precipitation events, and showed a rather erratic pattern. Root biomass was maximal about midway through the growing season. Grazed treatments typically had a higher peak root biomass in cooler grasslands, whereas no such response was seen in warmer grasslands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. III. Net primary production, turnover and efficiencies of energy capture and water use. Journal of Ecology 66, 573-597.

Summary

Levels of net primary production and efficiencies of energy capture and water use were investigated in six grassland types encompassing ten western North American grasslands. Above-ground net primary productivity (ANPP) ranged from 54 to 523 g/m2/yr; the average for grazed grasslands was 212 g/m2/yr compared with 236 g/m2/yr ungrazed grasslands (P<0.05). There was an apparent linear increase in ANPP with increasing precipitation up to approx. 500 mm/yr. Likewise, ANPP increased linearly with both growing-season and annual actual evapotranspiration (AET). Net root production ranged from 148 to 641 g/m2/yr, and was significantly higher on grazed compared with ungrazed grasslands. In general, root production increased with decreasing long-term mean annual temperature. Total net primary productivity (TNPP) ranged from 225 to 1425 g/m2/yr. Approx. 46% and 58% of the variablility in TNPP was explained by annual precipitation in ungrazed and grazed grasslands, respectively. Warmer grasslands had higher rates of crown turnover, corresponding to increased annual usable incident solar radiation and annual AET. Average rates of root turnover were 0.18, 0.30 and 0.49 for mixed-grass, tallgrass and shortgrass prairies, respectively, with a positive curvilinear relationship between root turnover and total annual usable incident solar radiation. Efficiency of energy capture in TNPP ranged from 0.12% to more than 1.4% for both ungrazed and grazed grasslands - communities dominated by cool-season species appeared to be comparable to or more efficient than warm-season species in terms of energy capture. Grasslands with higher water use efficiencies also had higher efficiency of energy capture - these two functional properties appeared to be positively related.

CPER

Dodd, J. L., and W. K. Lauenroth (1979). Analysis of the reponse of a grassland ecosystem to stress. IN: Perspectives in Grassland Ecology (N.R. French, ed.). Ecological Studies 32. Springer-Verlag, New York. pp. 43-58.

Lauenroth, W. K., and O. E. Sala (1992). Long-term forage production of North American shortgrass steppe. Ecological Applications 2, 397-403.

Summary

The relationship between annual forage grass production, and annual and seasonal precipitation and temperature, was evaluated for a shortgrass steppe site in north-central Colorado using a long-term data set (52 years). Forage production is related to above-ground net primary production (ANPP). Precipitation fluctuated randomly, but temperature had clear warming and cooling trends, including a 17-year warming trend from 1974 to 1990.

Forage production was significantly related to both annual and seasonal precipitation but not to temperature. Precipitation events of 15-30 mm accounted for most of the variability in production, because they contributed much of the variability in precipitation, and because they wetted those soil layers which have the largest effect on production. Forage production amplified variability in annual precipitation.

Production showed time lags of several years in responding to increases in precipitation. Change in vegetation structure has a characteristic response time, which constrains production responses in wet years. Regional ANPP-precipitation models have a steeper slope than long-term models due to this constraint caused by vegetation structure, and this highlights a weakness of exchanging space for time in predicting plant production patterns.

DZHANYBEK

Gilmanov, T. G., and A. I. Ivaschenko (1990). Primary biological productivity of ecosystems of the alkali complex of the clay semidesert of the North Transkaspian area. Izvestia Akademii Nauk SSSR. Ser. Biol. No. 4. pp. 600-611. (In Russian).

DICKINSON, HAYS, JORNADA

Sims, P. L., J. S. Singh, and W. K. Lauenroth (1978). The structure and function of ten western North American grasslands. I. Abiotic and vegetational characteristics. Journal of Ecology 66, 251-285.

Summary

Data are presented from ten central and western North American grasslands, covering six major grasslands types: mountain grassland, northwest bunchgrass, mixed-grass prairie, shortgrass prairie, tallgrass prairie and desert grassland. The experimental design at each location included two replications of ungrazed and grazed treatments. Measured environmental variables included precipitation, temperature and solar radiation, both as annual and growing-season values, along with annual and growing-season actual evapotranspiration. Seasonal above-ground live biomass averaged 94 g/m2 for the ten grasslands (98 g/m2 for ungrazed and 89 g/m2 for grazed treatments). Dead matter averaged about 160 g/m2 for ungrazed and 70 g/m2 for grazed treatments. Total above-ground standing crop (total clipped matter) averaged 203 g/m2 (245 g/m2 ungrazed; 161 g/m2 grazed). In general, the amount of litter corresponded to the total standing crop. The shortgrass prairie had the greatest amount of crown material, and the tallgrass prairie the least (about 275 g/m2 for short- and mixed-grass prairie, cf. 200 g/m2 for tallgrass prairie). Although grazing did not significantly influence crown material, it tended to increase under grazing in mixed and short-grass prairies. Root biomass ranged from 156 g/m2 in the desert grassland to as much as 2000 g/m2 in the mixed-grass prairie. There was an inverse relationship between root biomass dynamics and mean annual temperature; grazing generally resulted in an increase in root/shoot ratios, particularly for the cooler grassalands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. II. Intra-seasonal dynamics in primary producer compartments. Journal of Ecology 66, 547-572.

Summary

Intra-seasonal dynamics are presented for the various above-ground and below-ground primary producer compartments for ten central and western North American grassland sites. Above-ground live biomass followed either a unimodal growth pattern (for cool-season or warm-season communities, in general), or a bimodal pattern (for mixed cool- and warm-season communities). There were no significant differences between grazed and ungrazed treatments in seasonal live biomass, although there was a significant site x treatment interaction. Peak live biomass ranged from 84 to 336 g/m2, and showed a linear increase with growing-season precipitation up to 450 mm, leveling out beyond that. Maximum accumulation rates of live biomass were 0.4-6.5 g/m2/day. The recently-dead compartment showed maximum values soon after attainment of peak live biomass; old-dead, however, was maximal early in the growing season, declining thereafter as material was transferred to the litter compartment. Litter dynamics responded closely to precipitation events, and showed a rather erratic pattern. Root biomass was maximal about midway through the growing season. Grazed treatments typically had a higher peak root biomass in cooler grasslands, whereas no such response was seen in warmer grasslands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. III. Net primary production, turnover and efficiencies of energy capture and water use. Journal of Ecology 66, 573-597.

Summary

Levels of net primary production and efficiencies of energy capture and water use were investigated in six grassland types encompassing ten western North American grasslands. Above-ground net primary productivity (ANPP) ranged from 54 to 523 g/m2/yr; the average for grazed grasslands was 212 g/m2/yr compared with 236 g/m2/yr ungrazed grasslands (P<0.05). There was an apparent linear increase in ANPP with increasing precipitation up to approx. 500 mm/yr. Likewise, ANPP increased linearly with both growing-season and annual actual evapotranspiration (AET). Net root production ranged from 148 to 641 g/m2/yr, and was significantly higher on grazed compared with ungrazed grasslands. In general, root production increased with decreasing long-term mean annual temperature. Total net primary productivity (TNPP) ranged from 225 to 1425 g/m2/yr. Approx. 46% and 58% of the variablility in TNPP was explained by annual precipitation in ungrazed and grazed grasslands, respectively. Warmer grasslands had higher rates of crown turnover, corresponding to increased annual usable incident solar radiation and annual AET. Average rates of root turnover were 0.18, 0.30 and 0.49 for mixed-grass, tallgrass and shortgrass prairies, respectively, with a positive curvilinear relationship between root turnover and total annual usable incident solar radiation. Efficiency of energy capture in TNPP ranged from 0.12% to more than 1.4% for both ungrazed and grazed grasslands - communities dominated by cool-season species appeared to be comparable to or more efficient than warm-season species in terms of energy capture. Grasslands with higher water use efficiencies also had higher efficiency of energy capture - these two functional properties appeared to be positively related.

KHOMUTOV

Bystrickaya, T. L., and V. V. Osychnyuk (1975). Soils and primary biological productivity of steppes of Pryazovye (as exemplified by the "Khomutovskaya Steppe" reserve). Nauka, Moscow. 112 pp.

KLONG HOI KLONG

Kamnalrut, A., and J. P. Evenson (1992). Monsoon grassland in Thailand. In: Primary Productivity of Grass Ecosystems of the Tropics and Sub-tropics. (Long, S.P., M.B. Jones and M.J. Roberts, eds.). Chapman and Hall, London. pp. 100-126.

KONZA

Abrams, M. D., A. K. Knapp, and L. C. Hulbert (1986). A ten year record of above-ground biomass in a Kansas tallgrass prairie: effects of fire and topographic position. American J. Botany 73, 1509-1515.

Summary

Mid-season above-ground live biomass and dead matter were measured over a 10-year period (1975-84) in a northeast Kansas tallgrass prairie. Study sites included shallow, rocky upland and deep, non-rocky lowland soils for both unburned and burned watersheds, with burning annually in April. Over the 10-year period, lowland sites had significantly greater live biomass than upland sites for both burned and unburned prairie. Live biomass was greater on burned than unburned lowland sites, but was not significantly increased by fire on the upland sites. Averaged across upland and lowland sites, mid-season live biomass was 422 g/m2 on annually burned and 364 g/m2 on unburned sites for the 10-year period. During the severe drought year of 1980, all sites recorded their lowest live biomass for the study period (ranging from 185 to 299 g/m2). Live biomass was most strongly correlated with seasonal pan evaporation (r = -0.45 to -0.82), whereas dead biomass was correlated with the previous year's precipitation (r = 0.61 and 0.90 for upland and lowland sites, respectively). When above-ground biomass was sampled throughout the 1984 season and separated into several components, biomass of the graminoids was 40% lower. However, that of forbs and woody plants was 200-300% greater in the unburned than in the annually burned sites.

KONZA

Briggs, J. M., T. R. Seastedt, and D. J. Gibson (1989). Comparative analysis of temporal and spatial variability in above-ground production in a deciduous forest and prairie. Holarctic Ecology 12, 130-136.

Summary

Patterns of production in American tallgrass prairie and the adjacent Eastern deciduous forest were summarised over a 5-7 year period. Each ecosystem responded differentially to annual or growing season rainfall and solar energy (measured by pan water evaporation). Overall, forest productivity was negatively correlated with annual precipitation, whereas the prairie exhibited no relationship with precipitation. These differences probably reflect the lack of water limitation of the forest and the "downstream" position of the forest.....

KONZA

Knapp, A. K., J. M. Briggs, D. C. Hartnett, and S. L. Collins, eds. (1998). Grassland Dynamics: long-term ecological research in tallgrass prairie. Oxford University Press, New York. 386 pp.

KURSK

Bazilevich, N. I., and T. G. Gilmanov (1984). Conceptual balance models of natural and seminatural ecosystems of the Central Chernozem Biosphere Reserve. In: Conservation, Science and Society (Natural Resources Research XXI, Vol.2) UNESCO-UNEP. pp. 347-350.

KURUKSHETRA

Rajvanshi, R., and S. R. Gupta (1985). Biomass, productivity and litterfall in a tropical Dalbergia sissoo forest. J. Tree Science 4, 73-78.

Singh and Yadava (1974) Seasonal variation in composition, plant biomass and net primary productivity of a tropical grassland at Kurukshetra, India. Ecological Monographs 44, 351-376.

Summary

Variation in composition, plant biomass and net primary production (NPP) was analyzed for a tropical grassland within the campus of Kurukshetra University. At monthly intervals from May 1970 to May 1971, tillers were analyzed and harvests made for above-ground biomass, standing dead matter, litter and total below-ground biomass. Maximum above-ground biomass occurred in September (1974 g/m2) and maximum below-ground biomass in November (1167 g/m2 to 30 cm).

Examination of vertical distribution of above-ground biomass showed that different layers of vegetation are dominated by different species in different months. Above-ground NPP was maximum during the rainy season (1706 g/m2) and below-ground NPP was maximal during the dry winter season (785 g/m2). Total NPP was estimated at 3538 g/m2/yr. System transfer functions revealed that production was more directed above ground during the rainy season and below-ground during the dry season. Apparent efficiency of energy conversion was calculated at 1.66% on the basis of 50% total solar radiation.

LAMTO

Menaut, J-C., and J. Cesar (1979). Structure and primary productivity of Lamto savannas, Ivory Coast. Ecology 60, 1197-1210.

Summary

The savannas of Lamto (Ivory Coast) are characterised by their structural heterogeneity and by their dynamic evolution towards forest. The life-forms and phenological cycles of herbs, shrubs and trees reflect the constraining factors of the environment. Plant biomass and productivity are largely dependent upon soil type and climate. The dynamics of above-ground and below-ground biomass may be used to estimate net primary productivity. We compared the production of shrubs and trees, obtained from size-biomass correlations and growth measures, with herb production to provide an insight into the ecological balance of the savanna communities.

Bourliere, F., and M. Hadley (1970). The ecology of tropical savannas. Ann. Rev. Ecology and Systematics 1, 125-152.

MEDIA LUNA

Defosse, G. E., M. B. Bertiller, and J. O. Ares (1990). Above-ground phytomass dynamics in a grassland steppe of Patagonia, Argentina. J. Range Management 43, 157-160.

Summary

Above-ground biomass and litter dynamics of a grassland steppe in Patagonia, Argentina, were studied at monthly/bimonthly intervals for two years. Festuca pallescens (St. Yves) Parodi produced about 95% of the total annual biomass. Peaks of live biomass were recorded in spring-summer of the first growing season (33.6 g/m2) and in early spring (35 g/m2) and fall (32.7 g/m2) of the second growing season. Less abundant forage grasses included Poa ligularis, Bromus setifolius, Hordeum comosum and Rytidosperma virescens. Shrubs and forbs represented less than 2% of the total annual biomass. The relationships between biomass production of the main species and some environmental variables are discussed. These results will contribute to the knowledge of biomass dynamics and forage availability, and permit the designing of appropriate grazing schedules and range management planning.

MONTECILLO

Garcia-Moya, E., and P. Montanez Castro (1992). Saline grassland near Mexico City. In: Primary Productivity of Grass Ecosystems of the Tropics and Sub-tropics. (Long, S.P., M.B. Jones and M.J. Roberts, eds.). Chapman and Hall, London. pp. 70-99.

NAIROBI

Kinyamario, J. I., and S. K. Imbamba (1992). Savanna at Nairobi National Park, Nairobi. In: Primary Productivity of Grass Ecosystems of the Tropics and Sub-tropics. (Long, S.P., M.B. Jones and M.J. Roberts, eds.). Chapman and Hall, London. pp. 25-69.

NAIROBI / MONTECILLO / KLONG HOI KLONG

Long, S. P., E. Garcia Moya, S. K. Imbamba, A. Kamnalrut, M. T. F. Piedade, J. M. O. Scurlock, Y. K. Shen, and D. O. Hall (1989). Primary productivity of natural grass ecosystems of the tropics: a reappraisal. Plant and Soil 115, 155-166.

Summary

We studied net primary productivity of four contrasting tropical grasslands, and show that these ecosystems are far more productive than earlier suggested, when full account is taken of losses of plant organs above and below-ground. Earlier estimates were provided mainly by the International Biological Programme (IBP), where production was determined on the basis of changes in vegetation mass alone, and would not necessarily have taken full account of organ losses and turnover. Calculations at three of our sites based on established methodology using changes in plant mass alone (i.e. that used by the IBP) proved to be serious underestimates when account was taken of losses simultaneously with measurements of change in plant mass. Accounting for turnover of material at these three sites resulted in productivities up to five times higher than were obtained using the standard IBP procedure. An emergent C4 grass stand at a fourth site in the Amazon attained a productivity which approaches the maximum recorded for agricultural crops. However, estimated productivity at this site, taking into account organ losses, only slightly exceeded that obtained with IBP methods. These conclusions have wider implications in prediction of global carbon cycling by grassland ecosystems, remote sensing of plant productivity and impact assessment of conversion to arable crops.

NYLSVLEY

Grunow, J. O., H. T. Groeneveld, and S. H. C. du Toit (1980). Above-ground dry matter dynamics of the grass layer of a South African tree savanna. J. Ecology 68, 877-879.

Summary

The annual dynamics of various components and species of the herb layer in broad-leaved deciduous savanna were determined by harvest techniques. Difference methods were used to determine the mean flow rate between components such as above-ground grazeable live biomass, standing dead biomass and litter. Above-ground net primary productivity (ANPP) was calculated by integration of a "growth rate" curve, derived from a curve of live biomass during the year which was fitted to field harvest results using two opposing Gompertz functions representing "growth" and "death". "Growth rate" and "death rate" were derived from these, and their difference gave the "rate of change of biomass". These curves also give functions for instantaneous rates, and are useful for computer simulations.

In the open ground between trees, ANPP of the herb layer was 76 g/m2/year (60 g/m2/year for grasses alone; both figures including 10 g/m2/year eaten by insects). Averaged over 3 years, the peak rate of biomass accumulation for the grass layer in the open was 5.2 g/m2/week in early December (in the austral summer); however, in one year this was as high as 9.3 g/m2/week. These figures correspond to 0.1 and 0.14 g/g live biomass per day on a dry matter basis.

Peak grazeable above-ground live biomass was attained between December and mid-February; for the grass layer, this amounted to 88 g/m2 in the open, 54 g/m2 beneath the trees, and 78 g/m2 overall. Peak current-year live biomass of the tree and shrub layer was 134 g/m2. Excluding twigs, 188 g/m2 was potentially edible by large herbivores, but species selectivity and restricted browsing height result in incomplete use of this potential. Mean total live plus dead root matter for the grass and tree layers was 3700 g/m2 beneath the trees and 864 g/m2 between them. Mean live plus dead matter of the herb layer was 301 g/m2.

Scholes, R. J., and B. H. Walker (1993). An African Savanna: synthesis of the Nylsvley study. Cambridge University Press. 306 pp.

OLOKEMEJI

Hopkins, B. (1962). Vegetation of the Olokemeji Forest Reserve, Nigeria. I. General features of the reserve and the research sites. J. Ecology 50, 559-598.

Summary

The physical features, climate, history and vegetation of the reserve are described. Both of the main vegetation types in south-western Nigeria are present; moist semi-deciduous forest which is the climatic climax, and derived savanna woodland which is a biotic fire climax. The secondary nature of both are due to previous cultivation.

Hopkins, B. (1966). Vegetation of the Olokemeji Forest Reserve, Nigeria. IV. The litter and soil with special reference to their seasonal changes. J. Ecology 54, 687-707.

Hopkins, B. (1968). Vegetation of the Olokemeji Forest Reserve, Nigeria. V. The vegetation on the savanna site with special reference to its seasonal changes. J. Ecology 56, 97-115.

Summary

In terms of both dry weight and height, most grass production appears to take place during the wet season, and may also be stimulated by fire. Maximum dry weight of the herb stratum is 6.8 t/ha and maximum LAI is about 6.0. Four monthly photographs are presented to illustrate the seasonal changes. Quadrat data were subjected to ordination by principal component analysis and association analysis.

Hopkins, B. (1965). Observations on savanna burning in the Olokemeji Forest Reserve, Nigeria. J. Applied Ecology 2, 367-381.

Summary

Tree cover was not significantly related to dry weight of the herb layer before or after burning. The proportion of the herb layer burned was 25% early in the dry season, but averaged 84% from January onwards. Fire temperatures were measured with heat-sensitve paints, and were generally over 540 C at ground level, decreasing with height. Three-quarters of annual above-ground production of herbs is lost when the savanna is burned in December. Late burning for five consecutive years reduced the tree population by 32%.

OTRADNOE

Guricheva, N. P., O. M. Demina, G. I. Kozlova, et al. (1975). Productivity of meadow communities. In: Resources of the Biosphere (Results of Soviet IBP studies) Vol.1. Nauka, Leningrad. pp. 96-127.

OSAGE

Risser, P. G., E. C. Birney, H. D. Blocker, S. W. May, W. J. Parton, and J. A. Wiens (1981). The True Prairie Ecosystem. US/IBP Synthesis 16. Hutchinson Ross, Stroudsberg. 557 pp.

OSAGE, PANTEX

Sims, P.L., J.S. Singh and W.K. Lauenroth (1978) The structure and function of ten western North American grasslands. I. Abiotic and vegetational characteristics. Journal of Ecology 66, 251-285.

Summary

Data are presented from ten central and western North American grasslands, covering six major grasslands types: mountain grassland, northwest bunchgrass, mixed-grass prairie, shortgrass prairie, tallgrass prairie and desert grassland. The experimental design at each location included two replications of ungrazed and grazed treatments. Measured environmental variables included precipitation, temperature and solar radiation, both as annual and growing-season values, along with annual and growing-season actual evapotranspiration. Seasonal above-ground live biomass averaged 94 g/m2 for the ten grasslands (98 g/m2 for ungrazed and 89 g/m2 for grazed treatments). Dead matter averaged about 160 g/m2 for ungrazed and 70 g/m2 for grazed treatments. Total above-ground standing crop (total clipped matter) averaged 203 g/m2 (245 g/m2 ungrazed; 161 g/m2 grazed). In general, the amount of litter corresponded to the total standing crop. The shortgrass prairie had the greatest amount of crown material, and the tallgrass prairie the least (about 275 g/m2 for short- and mixed-grass prairie, cf. 200 g/m2 for tallgrass prairie). Although grazing did not significantly influence crown material, it tended to increase under grazing in mixed and short-grass prairies. Root biomass ranged from 156 g/m2 in the desert grassland to as much as 2000 g/m2 in the mixed-grass prairie. There was an inverse relationship between root biomass dynamics and mean annual temperature; grazing generally resulted in an increase in root/shoot ratios, particularly for the cooler grassalands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. II. Intra-seasonal dynamics in primary producer compartments. Journal of Ecology 66, 547-572.

Summary

Intra-seasonal dynamics are presented for the various above-ground and below-ground primary producer compartments for ten central and western North American grassland sites. Above-ground live biomass followed either a unimodal growth pattern (for cool-season or warm-season communities, in general), or a bimodal pattern (for mixed cool- and warm-season communities). There were no significant differences between grazed and ungrazed treatments in seasonal live biomass, although there was a significant site x treatment interaction. Peak live biomass ranged from 84 to 336 g/m2, and showed a linear increase with growing-season precipitation up to 450 mm, leveling out beyond that. Maximum accumulation rates of live biomass were 0.4-6.5 g/m2/day. The recently-dead compartment showed maximum values soon after attainment of peak live biomass; old-dead, however, was maximal early in the growing season, declining thereafter as material was transferred to the litter compartment. Litter dynamics responded closely to precipitation events, and showed a rather erratic pattern. Root biomass was maximal about midway through the growing season. Grazed treatments typically had a higher peak root biomass in cooler grasslands, whereas no such response was seen in warmer grasslands.

Sims, P. L., and J. S. Singh (1978). The structure and function of ten western North American grasslands. III. Net primary production, turnover and efficiencies of energy capture and water use. Journal of Ecology 66, 573-597.

Summary

Levels of net primary production and efficiencies of energy capture and water use were investigated in six grassland types encompassing ten western North American grasslands. Above-ground net primary productivity (ANPP) ranged from 54 to 523 g/m2/yr; the average for grazed grasslands was 212 g/m2/yr compared with 236 g/m2/yr ungrazed grasslands (P<0.05). There was an apparent linear increase in ANPP with increasing precipitation up to approx. 500 mm/yr. Likewise, ANPP increased linearly with both growing-season and annual actual evapotranspiration (AET). Net root production ranged from 148 to 641 g/m2/yr, and was significantly higher on grazed compared with ungrazed grasslands. In general, root production increased with decreasing long-term mean annual temperature. Total net primary productivity (TNPP) ranged from 225 to 1425 g/m2/yr. Approx. 46% and 58% of the variablility in TNPP was explained by annual precipitation in ungrazed and grazed grasslands, respectively. Warmer grasslands had higher rates of crown turnover, corresponding to increased annual usable incident solar radiation and annual AET. Average rates of root turnover were 0.18, 0.30 and 0.49 for mixed-grass, tallgrass and shortgrass prairies, respectively, with a positive curvilinear relationship between root turnover and total annual usable incident solar radiation. Efficiency of energy capture in TNPP ranged from 0.12% to more than 1.4% for both ungrazed and grazed grasslands - communities dominated by cool-season species appeared to be comparable to or more efficient than warm-season species in terms of energy capture. Grasslands with higher water use efficiencies also had higher efficiency of energy capture - these two functional properties appeared to be positively related.

PAMPA DE LEMAN

Bertiller, M. B. (1984). Specific primary productivity dynamics on arid ecosystems: a case study in Patagonia, Argentina. Acta Oecologica: Oecologia Generalis 5, 365-381.

Summary

A model has been fitted to field data describing the dynamics of above-ground compartments of dominant plant species in a desert dwarf shrub steppe in southern Chubut (Argentina). Nassauvia glomerulata (Compositae) is a relatively ungrazed shrub which taps water from deep soil layers and shows scarcely developed periodicity of green tissue activity. Poa dusenii and Hordeum comosum are the dominant palatable grasses, which vary in degree of opportunism for the successful use of water after rains. Quantification of a number of plant ecophysiological characteristics like productivity, senescence, etc. and their relation with key environmental factors, was achieved by exploring a number of ad hoc regression models, in order to improve strategies for herbivore management.

RIO MAYO - PATAGONIA

Soriano, A. (1983). Deserts and semideserts of Patagonia. In: Temperate Deserts and Semi-deserts (N.E. West, ed.) Elsevier, Amsterdam. pp. 423-460.

Fernandez, R. J., O. E. Sala, and R. A. Gulluscio (1991). Woody and herbaceous above-ground production of a Patagonian steppe. J. Range Management 44, 434-437.

Summary

Above-ground net primary production (ANPP) of the Patagonian steppe in south-western Chubut (Argentina) was estimated using a harvest technique to assess the herbaceous (mainly grass) component and a double sampling technique to evaluate shrub production. The latter technique involves the measurement of plant dimensions and the harvest of shrub biomass in small plots. By virtue of having an explicit biological model which considers both shrub size and production per unit surface of plant, this technique allows comparisons between years, sites and treatments. Detailed estimates of ANPP gave a value of 79 g dry matter (DM)/m2/year (S.E. = 19 g DM/m2/year) for an annual rainfall of 191 mm. This estimate of ANPP fits (±17%) the predictions of four models relating primary production to annual precipitation. Two thirds of production was accounted for by perennial grasses and one third by shrubs. A less detailed method, which uses only peak biomass, gave ANPP estimates for four additional years ranging from 21 to 75 g DM/m2/year, whilst annual precipitation over this period amounted to 55-167 mm. During a year of extreme drought, there was a large reduction in ANPP; however, there were no increases in ANPP during years with above-average precipitation. This suggests that the relationship between carrying capacity and precipitation for the Patagonian steppe may be non-linear.

SHORTANDY

Titlyanova, A. A., V. I. Kiryushin, I. P. Okhin'ko, et al. (1984). Agrocoenoses of the Steppe Zone. Nauka, Novosibirsk (in Russian). 247 pp.

TOWOOMBA

Donaldson, C. H., G. Rootman, and D. Grossman (1984). Long-term nitrogen and phosphorus application to veld. Journal of the Grassland Society of Southern Africa 1(2), 27-32.

Summary

Long-term effects are reported for a 5N x 3P factorial fertiliser application trial on the hay yields, botanical composition and soil properties of veld (savanna grassland). Significant increases in hay yields were recorded during most years, with a strong correlation (r=0.757) between mean annual hay yields and annual rainfall, over all 15 treatment combinations.

N and N+P fertiliser lowered the percentage basal cover of the grass tribe Andropogoneae, with the exception of Heteropogon contortus, which increased significantly at the lower fertiliser levels. The basal cover of the Paniceae generally increased with N and P fertiliser application, but the Eragrosteae showed little in the way of definite trends.

Increased N and P levels generally resulted in decreased soil pH, Ca, Mg and K, and increased compaction of the soil surface layer. However, higher levels of N x P resulted in greater rates of water infiltration than in the control plots, although initial infiltration rates were greatest in the control plots. Despite some undesirable effects of fertilisers on basal cover and certain chemical and physical properties of the soil, the fertilised plots maintained a high level of production.

TULLGARNSNASET

Wallentinus, H.-G. (1973). Above-ground primary production of a Juncetum gerardi on a Baltic sea-shore meadow. Oikos 24, 200-219.

Summary

Above-ground NPP of a Juncetum gerardi was analyzed by repeated clipping during the growing season, and rate of disappearance of dead matter was determined. Annual ANPP was calculated according to various methods: peak biomass plus dead matter gave 324 g/m2, sum of species maxima gave 363 g/m2, and increments of biomass plus dead matter gave about 400 g/m2. The mean estimate of several methods which accounted for disappearance of dead matter was 430 g/m2. Disappearance of dead matter reached a peak in July-August of 0.016 g/g/day.

TUMENTSOGT

Chuluun, Togtohyn, D. S. Ojima, Jargalsaihan Luvsandorjiin, J. Dodd, and S. Williams (1995). Simulation studies of grazing on the Mongolian steppe, pp. 561-562, in: Proceedings of the 5th International Rangeland Congress, Salt Lake City, Utah, U.S.A., July 1995 (N.E. West, ed.). Society of Range Management, Denver, Colorado, U.S.A.

Summary

Environmental and management factors affecting the Mongolian Steppe production were studied. A combination of field observation and model simulation was used to determine the linkage between environmental and management factors on long-term and short-term sustainability of the Mongolian Steppe. Early growing seasonal precipitation is one of the major driving factors for plant productivity in this ecosystem. The sandy soils of the Mongolian Steppe contribute to plant productivity, and are more susceptible to soil carbon losses under increased grazing intensity. Over most of their area, Mongolian grasslands are in good condition in terms of soil organic matter content. However, these grassland ecosystems are susceptible to changes in grazing management. Land use policies in the Mongolian Steppe should incorporate traditional approaches in developing a sustainable grazing system.

Dashnyam, B. (1974). Flora and Vegetation of the Eastern Mongolian Steppe. Mongolian Academy of Sciences Publ., Ulaanbaatar (in Mongolian).

TUMUGI

Xiao, X. M., D. Chen, Y. M. Peng, X. Y. Cui, and D. S. Ojima (1996). Observation and modeling of plant biomass of meadow steppe in Tumugi, Xingan league, Inner Mongolia, China. Vegetatio 127, 191-201.

Summary

Long-term dynamics of plant biomass of Filifolium sibiricum steppe, Stipa baicalensis steppe and Leymus chinense (syn. Aneurolepidium chinense) steppe were examined, relative to interannual variation of precipitation and temperature during 1981-1990 in the Tumugi, Xingan League, eastern Inner Mongolia, China. Average annual precipitation was 411 mm. Peak live aboveground biomass (PLAB) was 152 g/m2 for F. sibiricum and S. baicalensis steppe and 162 g/m2 for L. chinense steppe. Peak live belowground biomass (PLBB) varied between 968 g/m2 for F. sibiricum steppe and 1022 g m/2 for L. chinense steppe. The coefficient of variation (CV) in annual precipitation (25%) was lower than the CV in PLAB (35% to 37%) but larger than the CV in PLBB (10%) of the three meadow steppe sites. Rain use efficiency was 3.6 gDM/m2/cm/yr for F. sibiricum steppe and S. baicalensis steppe, and 3.9 gDM/m2/cm/yr for L. chinense steppe, respectively. Simulation results with the CENTURY ecosystem model agreed reasonably well with the observed soil organic matter, seasonal dynamics and interannual variation of plant biomass of these three steppe sites during 1981-1990. The CENTURY model is slightly more successful than the empirical regression models that use annual precipitation to estimate PLAB of these meadow steppe over time. The seasonal distribution as well as the interannual variation in precipitation and temperature are important controls of temporal dynamics of plant biomass, rain use efficiency, carbon flux and carbon storage of these meadow steppe ecosystems.

TUVA

Gorshkova, A. A. (1986). In: Titlyanova, A. A. (ed.) Productivity of Haymows and Pastures. Nauka, Novosibirsk. pp. 123-129 (in Russian)

VINDHYAN

Pandey, C. B., and J. S. Singh (1992). Rainfall and grazing effects on net primary production in a tropical savanna, India. Ecology 73, 2007-2021.

Summary

We examined the effects of rainfall amount, rainfall distribution and grazing intensity on net primary production (NPP) and herbivory for a dry tropical savanna. In a permanently protected savanna, above-ground and below-ground NPP ranged from 329 to 741 g/m2/yr, and from 404 to 838 g/m2/yr, respectively. Both were positively correlated to annual rainfall, and were more sensitive to late rainy season rainfall than early rains. Total herbaceous NPP ranged from 836 to 1579 g/m2/yr, and total herbaceous + woody NPP ranged from 1190 to 1910 g/m2/yr. This is similar to the NPP of native tropical dry deciduous forest, except that the production of herbaceous species is 61% lower in the forest. Including below-ground NPP in the 0-50 cm soil layer, total NPP was higher than that of native forest.

Grazing stimulated 4-45% increase in above-ground NPP, with greater effect in light or moderately grazed sites; however, it reduced below-ground NPP by 25-65%, with the greatest effect in heavily grazed sites. Below-ground NPP in grazed sites was inversely related to rainfall. By comparing NPP within and without temporarily fenced plots, herbivore consumption was estimated at 476-734 g/m2/yr; this was correlated to NPP and rainfall. Live green biomass, being a function of soil moisture, was highest in a high rainfall year.

XILINGOL

Xiao Xiangming, Jiang Shu, Wang Yifeng, D. S. Ojima, and C. D. Bonham (1995). Temporal variation in aboveground biomass of Leymus chinense steppe from species to community levels in the Xilin River Basin, Inner Mongolia, China. Vegetatio 123, 1-12.

Summary

Long-term dynamics of above-ground biomass, net primary production and efficiencies of water use are reported for 1980-1989 in the Leymus chinense (syn. Aneurolepidium chinense) steppe of the Xilin river basin, within the Unesco/MAB Xilingol Steppe Biosphere Reserve, Inner Mongolia. The response of above-ground biomass to interannual fluctuations in precipitation and temperature was examined at the levels of community, growth form and species. Annual above-ground net primary production (ANPP) varied from 154 g/m2/year in 1980 to 319 g/m2/year in 1988, with a mean of 249 g/m2/year and a coefficient of variation of 25%. ANPP was not significantly correlated to annual precipitation and total precipitation during April-September (p<0.05 level), but precipitation in May and August accounted for 69% of interannual variation of ANPP. Mean values for rain use efficiency and water use efficiency were 8.1 kg (DM) ha/mm/year and 0.89 g/mm, respectively.

The above-ground biomass of various growth forms and species showed different response patterns to interannual variation of precipitation and temperature. Monthly and seasonal distributions of precipitation and temperature were the key controls for above-ground biomass of individual species.

Zhao, X., Y. Yao, and R. Yang (1988). Ecological geographical characteristics and outlook of natural grasslands resources in Xilin river basin. In: Inner Mongolia Grassland Ecosystem Research Station (ed.). Research on Grassland Ecosystem 3, 184-226. Science Press, Beijing (Chinese with English abstract).