Ecosystem Project Research Articles

Temperature and its variability in oak forests in the southeastern Missouri Ozarks

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 08:209-223 (1997) - DOI: https://doi.org/10.3354/cr008209 Temperature and its variability in oak forests in the southeastern Missouri Ozarks Ming Xu1,*, Jiquan Chen1, Brian L. Brookshire2 1School of Forestry and Wood Products, Michigan Technological University, Houghton, Michigan 49931, USA2Missouri Department of Conservation, Jefferson City, Missouri 65102, USA *Present address: Department of ESPM, University of California at Berkeley, Berkeley, California 94720-3310, USA. Email: mingxu@nature.berkeley.edu This paper examines air and soil temperature, their variabilities, and their relationships with decomposition and ground flora diversity within an oak Quercus forest in the southeastern Missouri Ozarks (USA). We conducted 3 experiments with 9 mobile weather stations at Missouri Ozark Forest Ecosystem Project (MOFEP) study sites from September 1994 to August 1995. We used the cotton strip assay technique to quantify decomposition rate and Simpson's diversity index to evaluate the diversity of the ground flora. We found that air temperature at each site differed significantly from every other site (p < 0.001) based on a temporal scale of 20 min; this was also the case for soil temperature (p < 0.001). The spatial variation of soil temperature was consistently greater than that of air temperature. The spatial variation of air temperature increased with increasing spatial scale. Spatial variation of soil temperature increased rapidly from the 0 to ca 40 m scale, then decreased slowly before it began to increase again at a spatial scale of ca 700 m. Temperature was not highly correlated to decomposition rate in the study area (correlation coefficients were 0.51 and 0.64 for air and soil temperature, respectively). The spatial variation of temperature was inversely related to the species diversity of the ground flora (R2 was 0.87, 0.93, and 0.76 for air, soil surface, and soil temperature, respectively, at the 400 m scale). These results suggest that temperature variation can be quite significant, even at the stand level, and can impact some ecological patterns and processes at the same scale. Forest microclimate · Ecological Land Type (ELT) · Missouri Ozark Forest Ecosystem Project (MOFEP) · Temperature variability · Scale issues Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 08, No. 3. Publication date: October 09, 1997 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 1997 Inter-Research.

The Temporally Integrated Monitoring of Ecosystems (TIME) Project Design: 1. Classification of Northeast Lakes Using a Combination of Geographic, Hydrogeochemical, and Multivariate Techniques

This investigation is part of the Temporally Integrated Monitoring of Ecosystems ((TIME) project, an effort to meet the difficult challenge of monitoring surface water quality in the northeastern United States for signs of change in response to the Clean Air Act Amendments of 1990. The overall objective of the study was to develop a unified scheme for classifying lakes in the northeast into relatively homogeneous groups and improve the likelihood of detecting water quality trends in the region. The study approach involved combining the best elements of several procedures recently used for defining regional subpopulations of lakes; these were termed the hydrogeochemical model (HM), geographical model (GM), and multivariate statistical model (MSM). Lake and watershed data from the U.S. Environmental Protection Agency Eastern Lake Survey (ELS) were used to evaluate the classification methods and their modifications. After preliminary comparisons were made of the three classification schemes, it was concluded that the resulting subpopulations indicated that there was meaningful similarity among methods but that the significant dissimilarity reflected distinctive attributes of each classification method. These differences were deemed important; accordingly, integration of the methods entailed efforts to preserve parts of each. This was accomplished by assigning each lake of the ELS data set into a lake cluster that had been defined by jointly applying the HM and GM methods. Subsequently, the jointly classified clusters were aggregated by coupling an application of the MSM (cluster analysis) with subjective judgment regarding termination of the process of cluster formation. This integration of procedures gave rise to nine subpopulations that separated mainly on the basis of hydrogeochemical factors, though geographic influences also were evident in the results. The integrated classification procedure provided an explicit method involving the combination of several kinds of data to yield lake subpopulations. Although the process of integrating this information may stand alone as a useful exercise, the results obtained from the integrated classification model exhibited less dispersion than those formed by the parent procedures. This is an important consideration when subpopulation homogeneity is wanted as a means to improve trend detection. From the view of statistical efficiency, therefore, the integrated procedure may be considered to be more optimal than the parent schemes. When the complexity of the integrated approach is considered, however, we conclude that the next most precise classification scheme, the HM approach, may be preferred over the integrated classification for use in the design of an actual monitoring program.

The Temporally Integrated Monitoring of Ecosystems (TIME) Project Design: 2. Detection of Regional Acidification Trends

The Temporally Integrated Monitoring of Ecosystems (TIME) project utilizes a hybrid sampling approach to achieve its goal of assessing whether emissions controls, mandated by the Clean Air Act Amendments of 1990, have had their intended effect on lakes and streams. A randomly placed triangular grid is used to select, with known probability, lakes and streams for sampling on either an annual basis (in the case of acid‐sensitive sites) or on a 4‐year rotation. Data from these sites will be used to detect trends in regional characteristics of the target populations. The ability of TIME to detect trends in acid‐neutralizing capacity (ANC) and SO42− is dependent on the amount of variability (year‐to‐year, site‐to‐site, within‐season, and site‐by‐year interaction) exhibited by the sites. In particular, high levels of year‐to‐year variability lead to very low power to detect trends. One method to minimize year‐to‐year variability is to group together sites with similar characteristics. By performing trends tests on seven separate subpopulations the TIME design for northeastern U.S. lakes is predicted to be able to detect trends of the expected magnitudes in ANC (0.5 μeq L−1 yr−1) and SO42− (1.2 μeq L−1 yr−1 with power at or above the 0.90 level and α=0.10.

In vivo metabolism of benzo(a)pyrene in the mussel Mytilus galloprovincialis

The use of cytochrome P4501A (CYP1A) and other measurements as biomarkers was investigated in liver of goby (Z. ophiocephalus) and digestive gland of mussel (M. galloprovincialis) from several sites in the Venice lagoon as part of the UNESCO-MURST Venice Lagoon Ecosystem Project. Most tissue contaminants (PAHs, PCBs, DDTs) and biochemical measurements varied seasonally. Elevated 7-ethoxyresorufin O-deethylase activity and CYP1A-protein levels in goby were correlated with high tissue contaminant levels at the industrial Porto Marghera site. On occasions, activities of the antioxidant enzymes catalase and putative DT-diaphorase (resorufin reductase activity) in male but not female goby were also higher at Porto Marghera than other sites, but no differences were seen in Superoxide dismutase (SOD) activity. A range of measurements (SOD, catalase, NADPH-cytochrome c reductase and glutathione S-transferase activities, P450 and ‘418-peak’ contents) in mussel showed little difference between sites. However, indications were obtained of elevated levels of CYP1A1-like mRNA, CYP1A-like protein and metabolism of benzo[a]pyrene to free metabolites in mussels from the Venice lagoon compared to a site in the Adriatic Sea. The studies demonstrate the usefulness of CYP1A as a biomarker for organic pollution in fish and indicate some potential for its application in molluscs.

Indicator Species and Scale of Observation

Arthropods, because of their small size, diversity, and sensitivity to environmental variability, can be good indicators of habitat heterogeneity, ecosystem biodiversity, and environmental stress (Brown 1991; Hafernik 1992; Pearson & Cassola 1992; Kremen et al. 1993; Oliver 1993; Kremen 1994). Species richness among arthropod taxa can predict the richness of other taxa from an indicator (Pearson 1992), priority (Oliver 1993), or target (Kremen 1994) taxon. Erwin (1982) hypothesized that there were 30 million tropical arthropods, an estimate based partly on beetles comprising 40% of described taxa. May (1992) cited a lower estimate of six million, based on the percentage of British insects that were butterflies (0.3%). He pointed out, however, that relationships among taxa could vary from place to place, leading to great uncertainty in estimates of total richness. One factor in that uncertainty is that estimates of richness are invariably tied to areas of a particular size. Consequently, richness depends on scale of observation. If different taxa accumulate species at different rates as area increases, then correlations among taxa, or taxon percentages of total species richness, will vary with area size. Because a useful indicator has to be independent of sample size (Noss 1990), it is critical to measure the influence of sample size on indicator taxa. One way to test the influence of scale of observation is to collect samples in a hierarchical fashion so that smallscale samples can be aggregated into samples representing areas of increasing size. I sampled leaf litter invertebrates as part of the Missouri Ozark Forest Ecosystem Project (MOFEP), a large-scale, long-term study intended to examine the effects of timber harvesting on forest species. Litter samples were nested within plots nested within stands. By aggregating samples into plot data sets and plot data sets into stand data sets, the richness of eight arthropod taxa could be correlated across three scales of observation. By aggregating the stand data sets

Studies on isoenzymes of glutathione S-transferase in the digestive gland of Mytilus galloprovincialis with exposure to pollution

The possible utility of glutathione S-transferase isoenzymes in affinity purified extracts of digestive gland from Mytilus galloprovincialis as indicators of exposure to organic pollution has been assessed by fast protein liquid chromatography (FPLC) using a Mono-Q ion exchange column. Four main peaks of protein (isoenzymes 1–4) were detected in these chromatographic studies all of which displayed detectable catalytic activity with 1-chloro-2,4-dinitrobenzene and glutathione as substrates. The bulk of the activity with these substrates was associated with isoenzyme 1. The specific activity of cytosolic extracts from six sites in Venice Lagoon and the Adriatic Sea (UNESCO-MURST Venice Lagoon Ecosystem Project) decreased slightly with increasing tissue levels of chemical contaminants (hydrocarbons, PCBs and organochlorines). FPLC of affinity purified extracts from three of these sites was used to assess the possible variation in the levels of individual isoenzymes relative to pollution status. No difference was observed in the levels of these isoenzymes.

Assessment of the impact of organic pollutants on goby ( Zosterisessor ophiocephalus) and mussel ( Mytilus galloprovincialis) from the Venice Lagoon, Italy: Biochemical studies

The use of cytochrome P4501A (CYP1A) and other measurements as biomarkers was investigated in liver of goby ( Z. ophiocephalus) and digestive gland of mussel ( M. galloprovincialis) from several sites in the Venice lagoon as part of the UNESCO-MURST Venice Lagoon Ecosystem Project. Most tissue contaminants (PAHs, PCBs, DDTs) and biochemical measurements varied seasonally. Elevated 7-ethoxyresorufin O-deethylase activity and CYP1A-protein levels in goby were correlated with high tissue contaminant levels at the industrial Porto Marghera site. On occasions, activities of the antioxidant enzymes catalase and putative DT-diaphorase (resorufin reductase activity) in male but not female goby were also higher at Porto Marghera than other sites, but no differences were seen in Superoxide dismutase (SOD) activity. A range of measurements (SOD, catalase, NADPH-cytochrome c reductase and glutathione S-transferase activities, P450 and ‘418-peak’ contents) in mussel showed little difference between sites. However, indications were obtained of elevated levels of CYP1A1-like mRNA, CYP1A-like protein and metabolism of benzo[a]pyrene to free metabolites in mussels from the Venice lagoon compared to a site in the Adriatic Sea. The studies demonstrate the usefulness of CYP1A as a biomarker for organic pollution in fish and indicate some potential for its application in molluscs.

The Morrison Formation Extinct Ecosystems Project

The Morrison Extinct Ecosystem project is generating interesting results that, although preliminary in nature, are starting to converge on an integrated reconstruction of the Late Jurassic habitat in the Western Interior of the United States. A workshop in April, 1996, helped the participants learn where their data are in agreement and where remaining inconsistencies in the data exist. The workshop thus helped focus collective and individual efforts for the remaining field season so that additional field research and sample collection could be directed toward addressing the unresolved questions. A much more complete picture of the Morrison ecosystem is emerging, with such lines of evidence as the isotopic data confirming regional tectonic interpretations, and trace fossils adding subtle but significant clues to the interpretations of the ancient climate and water-table position and fluctuations. A mesic climate interpretation with a moderate amount of available moisture is derived from some of the plant fossils and, at first glance, contrasts with evidence of an arid to semi-arid climate based on the presence of saline, alkaline lake deposits; eolian strata; and evaporite deposits. Thus, the climate may have changed periodically or episodically, leaving evidence in the geologic record of the contrasting climate regimes-not all of which existed at the same time. A possible resolution of these discrepancies is that there was marked seasonality in which part of the year was relatively dry, as reflected by the arid to semiarid environmental indicators, whereas there may have been more precipitation during other parts of the year, as reflected by the more mesic environmental indicators. An additional factor that will need to be evaluated further is the role of the water table. The trace fossils suggest a fairly shallow water table that many of the plants, especially the larger ones, could tap throughout the year and therefore not be unduly affected by seasonal dryness. Also to be evaluated is the possibility that plants grew near stream courses or in overbank ponds in areas having a high water table, and that areas away from the streams were drier. These issues will be the focus of the remaining work, as outlined at the conclusion of the workshop.

Morrison Ecosystem Project

The Late Jurassic Morrison Formation is one of science's best windows into the world of dinosaurs and Mesozoic ecosystems. The Morrison Formation has significant exposures in many units within the Rocky Mountain Region of the National Park Service. These include Arches National Park (ARCH), Bighorn National Recreation Area (BIRO), Black Canyon of the Gunnison National Monument (BLCA), Capitol Reef National Park (CARE), Colorado National Monument (COLO), Curecanti National Recreation Area (CURE), Dinosaur National Monument (DINO), Glacier National Park (GLAC), Glen Canyon National Recreation Area (GLCA), Hovenweep National Monument (HOVE), and Yellowstone National Park (YELL). The Morrison Formation Extinct Ecosystems Project, hereafter called the Morrison Project, began on June 1 of 1994. The project is a multidisciplinary endeavor to determine the nature, distribution, and evolution of the ancient ecosystems that existed in the Western Interior of the United States during the Late Jurassic Epoch when the Morrison Formation and related rocks were deposited. The information obtained from the research can be used to suggest appropriate resource management actions and the project will also provide an improved understanding of the geological and paleontological history of these NPS units and better information for interpretive programs and publications.

Growth of nomadic and settled Turkana infants of northwest Kenya.

Turkana tribespeople reside in a semi-arid savanna ecosystem in northwest Kenya. For over a decade, Ngisonyoka Turkana nomads have been studied within a multidisciplinary framework that embraces ecology, anthropology, and human population biology. Original research objectives of the South Turkana Ecosystem Project were to study nomads longitudinally and within the context of the dry savanna ecosystem. These objectives have been expanded to incorporate settled Turkana who were nomads in the recent past, but who, for a variety of reasons, have taken up a life of sedentary cultivation. The research described here focused on comparisons of growth patterns of nomadic and settled infants from birth to 24 months of age. Infants were measured (recumbent length, weight, head circumference, arm and calf circumference, and selected skinfolds) in 1989 and 1990. Settled infants were slightly longer, but nomadic infants were heavier and fatter. Head circumferences were the same. Some variation was observed by season and year of measurement (from comparative surveys). Both groups showed pronounced weight faltering after 6 months of age when compared with U.S. NCHS reference values. Head circumference faltering was moderate and recumbent length faltering was only slight after 12 months of age. Comparisons of Turkana infant growth in the two populations can contribute indirectly to a better understanding of infant nutritional status, probable morbidity, and other factors, some of which may be linked to female reproduction.

Aspectos da biologia reprodutiva de fêmeas de Etropus longimanus Norman, 1933 (Bothidae) da região de Cabo Frio, Rio de Janeiro: 1. tamanho da primeira maturação, tipo e época de desova

Durante o período de novembro de 1986 a outubro de 1988 foram realizados estudos sobre a ictiofauna demersal na região de ocorrência do fenômeno da ressurgência em Cabo Frio, pelo Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM). A partir de coletas mensais da ictiofauna, efetuadas com arrasto de porta, e da água, para a obtenção dos valores da temperatura, constatou-se a abundância de Etropus longimanus na região. Foram obtidas 653 fêmeas, em diferentes tamanhos e fases de desenvolvimento gonadal, o que nos permitiu a realização de um estudo sobre alguns aspectos da biologia reprodutiva desta espécie, como o tamanho da primeira maturação, o tipo de desova e a época de reprodução na região. Estimou-se um comprimento padrão médio em que a população das fêmeas apresentam 50% de probabilidade de estarem sexualmente maduras, de 75 mm; e o comprimento padrão médio em que todas estão aptas à reprodução, de 95 mm. Verificou-se que E. longimanus apresenta um desenvolvimento ovacitório sincrónico em mais de dois grupos, sugerindo a ocorrência de desova múltipla. Os resultados obtidos indicaram que a desova ocorreu desde o final da primavera, até o início do outono, com picos máximos no verão, quando registrou-se os valores da temperatura da água entre 13,3ºC a 18.7ºC, época predominante de ressurgência na região.

Net Primary Production of a Perennial Grass Ley (Festuca pratensis) Assessed with Different Methods and Compared with a Lucerne Ley (Medicago sativa)

(1) The above-ground production of an established perennial grass (meadow fescue) ley in central Sweden was analysed by repeated clipping during 1982 and 1983. Standing vegetation was separated into living and dead material and surface litter was collected. Three methods were used to calculate net above-ground primary production (NAPP). Two of them accounted for death and shedding between samplings. (2) Depending on the calculation method, annual NAPP of ash-free dry mass varied between 903-985 and 810-1039 g m-2 in 1982 and 1983, respectively. The two methods which included biomass turnover gave the highest production values. (3) The underestimation in NAPP due to decomposition of litter between samplings was evaluated by applying a decomposition constant, estimated in a separate litter-bag experiment, to the mean amount of litter present during a sampling period. It was found to be <10%. (4) The mean daily growth rates of above-ground crop were 4 7 and 6 0 g m-2 in 1982 and 1983, respectively. The maximum recorded daily crop growth (22 0 g m2) occurred in early June 1983. (5) The study was part of a multi-disciplinary ecosystem project, and estimates of below-ground production and herbivore consumption were available, allowing total net primary production (NPP) to be estimated. Mean annual NPP was 1468 g m-2. (6) NPP was underestimated as rhizodeposition was not measured. Its underestimation from neglecting death and decomposition was less severe above than below ground. The amount of organic matter input to the soil system via litterfall was a minor part of the NPP but a significant part of the total organic matter supplied to the soil organic matter pool during a year. (7) Growth pattern and total NPP were compared with those of a lucerne ley grown in parallel with the meadow fescue ley. A severe drought in 1983 affected the grass ley more than the lucerne ley. Average annual NPP was similar in both crops, but the amount of standing dead was higher in the grass ley than in the lucerne ley. The allocation below ground was similar, about 30%, but root death was higher in the grass ley.

Habitat selection by the queens of the leaf-cutting ant Atta sexdens L. in Brazil

The founding of a new nest is the most crucial period in the life of an ant colony (Wilson 1971). Mechanisms that enhance colony survivorship during this phase are thus of great value. Of special importance is the search for a suitable habitat by the foundress queen, since established colonies of most ant species are unable to migrate over long distances (Wilson & Hunt 1966). That ant queens select the habitat in which they will found a new colony has been demonstrated for several temperate zone species (Brian 1952, Brian et al. 1966, Pontin 1960, Wilson & Hunt 1966) and for the Neotropical leaf-cutting ants Atta cephalotes L. and Acromyrmex octospinosus Reich (Cherrett 1968). In this paper, evidence that such a mechanism is operating among the foundress queens of another leaf-cutting ant species, Atta sexdens L., is presented. Furthermore, it is shown that, once in the preferred habitat, they search for the best microhabitat. Field work was done at 'Fazenda Dimona', a ranch located about 70 km north of Manaus, Brazil (600 4' W, 20 19 S). In this ranch two forest fragments of 1 ha, one of 10 ha and one of 100 ha were created during late 1984 to meet the requirements of the Minimum Critical Size of Ecosystem Project (a collaborative binational research project between the Instituto Nacional de Pesquisas da Amazonia and the World Wildlife Fund-US). A fifth fragment about 100 m wide and bordering a local stream, but not related to the MCSE Project, was created at the same time. Brachiaria grass was planted in the cleared area, but no efforts were made to maintain the pasture free of weed species. One year later, at the beginning of the study, stands of secondary vegetation 1-2 m tall, mainly Laetia procera (Poepp.) Eichl., Solanum rugosum Dun. and species of Cecropia, were present throughout the pasture. The vegetation of the fragments was a primary, terra-firme forest (as defined by Guillaumet 1987).

Tree densities and sex ratios in breeding populations of dioecious Central Amazonian Myristicaceae

ABSTRACTThe densities of the breeding populations and the sex of all flowering individuals were recorded for five dioecious canopy tree species of Central Amazonian Myristicaceae, in 11 study areas of the Minimum Critical size of Ecosystems Project totalling 22.5 ha. Adult population densities were extremely low, ranging from 0.38 to 1.61 ha–1 for the five species studied. In a 10 ha study plot the mean distance to the nearest flowering conspecific ranged from 48 to 100 m, while the mean distance to the nearest opposite sex conspecific was 147 m. The two most abundant species, Iryanthera macrophylla and Virola calophylla, both showed male-biased sex ratios, of 23:9 and 20:6, respectively. The size class distribution of males, females and non-flowering individuals in V. calophylla suggests that earlier reproductive maturation of male plants may provide a partial explanation for this bias. In I. macrophylla, since 95% of the individuals were observed flowering, the observed ratio is representative of the population, and may be caused by sex shifts from male to female. The low reproductive densities, combined with the skewed sex ratios and overlapping generations of these species, create very small effective breeding populations, placing species such as these at great risk in the face of deforestation and habitat fragmentation.

Ecology and Calls of Four Species of Amazonian Forest Frogs

First data on breeding biology and vocalization by the primary forest dwelling frog species Osteocephalus buckleyi, Chiasmocleis shudikarensis, Bufo dapsilis, and Leptodactylus rhodomystax, was obtained in the Central Amazon of Brazil in 1980, 1983, 1984, and 1985. Breeding habitat requirements of these species are quite specialized and emphasize the need for more ecological information on Amazonian forest frog species if efforts to preserve them in forest reserves are to be effective. Calling by Osteocephalus buckleyi and Chiasmocleis shudikarensis and Bufo dapsilis demonstrates certain vocal behaviors exhibited extensively by Amazonian forest frog species which may reflect predator avoidance strategies. A field survey of the frogs in the Insti- tuto Nacional de Pesquisas de Amazonica- World Wildlife Fund (U.S.) (I.N.P.A.- W.W.F.) primary forest reserves near Ma- naus in the Central Amazon of Brazil is part of I.N.P.A.-W.W.F.'s Minimum Crit- ical Size of Ecosystems (M.C.S.E.) project. The objectives and methods of the M.C.S.E. project are outlined in Lovejoy et al. (1984) and Lewin (1984) but basically, the project is an attempt to understand the ecology of primary Amazonian rainforest. Informa- tion on how plants and animals respond to restriction within forest fragments of different size will be used as the basis for conservation planning and design of na- ture reserves and national parks. The main goals of M.C.S.E.'s frog sub- project are to identify all species of primary forest frogs present in the I.N.P.A.-W.W.F. area, their habitat requirements for breed- ing, and their normal distributions and abundances within undisturbed primary forest. These data are needed to discern the effects of isolation within forest islands on breeding populations of frogs. An impor- tant tool used in the survey is knowledge of species vocalizations because most species of Amazonian forest frogs are dif- ficult to locate visually. An acoustic species list greatly extends the range of a survey and aids immeasurably in identification of habitat preferences and learning about the general ecology of the animal. Therefore all types of vocalization by a species are recorded and vocal patterns observed. First results of the anuran survey are presented in Zimmerman and Hodl (1983), Zimmer- man (1983), Zimmerman and Bogart (1984), and Zimmerman and Bierregaard (1986). The present study considers the identi- fication, ecology, and acoustics of four species of Amazonian forest frogs about which little or nothing was previously known: Osteocephalus buckleyi, Chiasmocleis shudikarensis, Bufo dapsilis, and Leptodactylus rhodomystax. Breeding biology and vocal behavior of these species illustrate certain characteristic features of the forest anuran community such as specificity of breeding habitat, infrequency of breeding, and in- frequent calling. The requirement of spe- cialized breeding habitat by many species and opportunistic breeding observed in some species has important implications for conservation. The widespread use of vocal patterns such as synchronized cho- rusing and low calling rates among forest frogs is interpreted as a predator avoidance strategy.

Ecology of Tropical Savannas.

The Ecological Studies series presents a symposium and workshop convened by the South African savanna ecosystem project. The 28 papers are divided into six sections: structure, determinants, function, dynamics and management. The contributing scientists were mostly from South Africa itself, with others from other African nations, Australia, Brazil, Venezuela, Israel and Europe. The opening section is mostly descriptive of savanna vegetation in several parts of the world, and is followed by papers on obvious ecological linkages, such as soils, soil nutrients and fire. Modern work on ecosystem metabolism considers processes such as water relations, herbivory, and nitrogen partition and near the end, dynamics and management are dealt with, mainly in the context of the concepts of stability and resilience.

Synthesis and Modelling of Intermittent Estuaries

Port Hacking is a small subtropical estuary, relatively unpolluted despite its location only 30 km south of Sydney on Australia's Pacific coast. It was the site of a 5‐year (1973–1978) multidisciplinary ecosystem project, focusing on the flow of carbon into, within, and out of the estuarine system. The ultimate goal of the project was the formulation and implementation of a predictive model of the carbon dynamics. However, this book, which summarizes the project, reports that the scientific team failed in its effort to reach the goal of a predictive model.

The distribution of macronutrients in a broad leaf woody savanna

Early work at Nylsvley, the study site of the South African Savanna Ecosystem Project, showed a low soil nutrient status. On the basis of this and in view of the low vegetation biomass compared to other similar ecosystems, it was suggested that nutrients may be limiting productivity in this Burkea africana dominated savanna. This study examined concentrations of total, ammonium and nitrate nitrogen in Burkea savanna (Hutton form, Chester series) soils with respect to depth and time of year. It further examined the concentrations of total Mg, K and P in the soil with respect to depth. The three major tree species, B. africana, Ochna pulchra and Terminalia sericea and the two dominant grasses, Digitaria eriantha and Eragrostis pallens were examined and N, Mg, K, P and S concentrations were determined in various components of each of these species. Results obtained for the three nitrogen forms in the soil showed spatial and a considerable temporal variation. The spatial variation can partly be ascribed to tree canopies and faunal disturbance. The considerable temporal variation can not be accounted for. From the low amount of Mg and K in vegetation relative to that in the soil, it was concluded that these nutrients are unlikely to be limiting. The data for P and S are insufficient to assess their possible limitation to productivity. The possibility that nitrogen may be a factor limiting productivity is discussed. Vroeë werk op die Nylsvley studieterrein van die Suid-Afrikaanse Savanne Ekosisteemprojek, het ’n lae grondvoedingstofkonsentrasie ge-toon. Met die oog hierop en die lae plantbiomassa van die gebied relatief tot ander soortgelyke ekosisteme, is voorgestel dat die produktiwiteit van hierdie savanne wat deur Burkea africana oorheers word, deur die voedingstofstatus van die grond beperk word. In hierdie studie is die totale-, ammoniak- en nitraatstikstofkonsen-trasie van Burkea savanne grond (Hutton Chester) ten opsigte van diepte sowel as die tyd van jaar ondersoek. Die totale Mg-, K- en P- konsentrasies in die grond ten opsigte van diepte is ook bepaal. N-, Mg-, K-, P- en S-konsentrasies is ook in die verskillende onderdele van die drie hoof boomsoorte, naamlik B. africana, Ochna pulchra en Terminalia sericea sowel as die twee hoof grassoorte, Digitaria eriantha en Eragrostis pallens ondersoek. Resultate vir die drie stikstofvorms in die grond het ’n ruimtelike variasie sowel as ’n aansienlike variasie met tyd getoon. Die ruimtelike variasie kan gedeeltelik deur kroonbedekking sowel as deur dierversteuring verklaar word. Die tydsgebonde variasie is onverklaarbaar. Die verhouding van die Mg- en K-inhoud van die plante tot dié van die grond is laag. Hieruit word afgelei dat dit onwaarskynlik is dat hierdie voedingstowwe beperkend is. Die gegewens vir P en S is onvoldoende om hulle moontlike beperkende invloed op produktiwiteit vas te stel. Die moontlikheid dat stikstof produktiwiteit beperk, word bespreek.

Diversity, structure and pattern in Nylsvley vegetation

After a brief description of the study area, Nylsvley — site of the South African Savanna Ecosystem Project — and a summary of a recent phytosociological survey, an account is given of the following aspects of the vegetation of the area: species diversity; woody plant structure; herbaceous layer cover and relative occurrence; ordination and pattern of the herbaceous layer; ordination and pattern of woody and herbaceous plants; and aboveground plant standing crop from two surveys. Results are based on both published and unpublished studies. Methods, which are described briefly, included entire stand mensuration for structure and standing crop, narrow transects for pattern studies and the wheelpoint apparatus for cover and relative occurrence. Throughout the paper the great diversity in structure, pattern, species composition and aboveground plant standing crop found at the within-site scale and previously referred to as a ‘more than Daedalian maze’ is highlighted.

Termites of a South African savanna : I. List of species and subhabitat preferences.

This study describes the termite fauna of the South African Savanna Ecosystem Project study area at Nylsvley Reserve, Naboomspruit, northern Transvaal. Twenty species of fifteen genera and two families are recorded, and biological notes are given. The faunal composition is broadly similar to that of West African savannas, but a little impoverished. Main deficiencies are in variety of Macrotermitinae and Trinervitermes; Termitinae are broadly comparable.Most of the species occur in the flatter areas of broad-leaved savanna; three are restricted to open land bordering a marsh. Steeply rocky broad-leaved savanna lacks two species but has two others restricted to it; Acacia patches (including sites of former human settlement) have a much reduced variety of species.