Sandy Upland Research Articles

Contrasting patterns of resource limitation in tree seedlings across a gradient in soil texture

Resource competition theory for terrestrial plant communities explains gradients in species composition among various habitats as the outcome of differential supply and demand for limiting resources. To examine one group of assumptions of this theory, for forest vegetation in southeastern Texas, we grew seedlings of three broadly distributed tree species, Acerrubrum L. (red maple), Liquidambarstyraciflua L. (sweetgum), and Pinustaeda L. (loblolly pine), in intact soil cores collected from three sites located along a gradient in soil texture. We tested resource limitation in a temperature-controlled greenhouse with nutrient fertilization, light, and moisture treatments applied in a resource-minus or screening design. This design provided most resources at levels not limiting for growth while simulating (potentially limiting) field conditions for a single resource or group of related resources. Light was most limiting with clay-rich floodplain soil cores under simulated floodplain forest conditions. Soil nutrients were most limiting in sandy upland soil cores under upper slope forest conditions. Both light and soil nutrients were strongly limiting with loamy intermediate soil cores under simulated mesic forest conditions. The most limiting soil resource was phosphorus. The pattern of reciprocal limitation by aboveground or belowground resources in extreme habitats and joint limitation in intermediate habitats was consistent with requirements of the theory.

Effects of zero and conventional tillage on winter oilseed crops in West Bengal

Field experiments were conducted for 2 years on a well-drained upland sandy loam in West Bengal, India, to compare the performance of winter oilseed crops (safflower, niger, mustard cultivars Varuna and RW 351, linseed and yellow sarson) under two tillage treatments—zero and conventional tillage. With zero tillage, weeds were suppressed by the application of herbicide before sowing. Greater seed yields (27%) were achieved with conventional tillage as compared with zero tillage. However, safflower and linseed showed no significant difference in seed yields between the two tillage systems in the second year.

The Carlisle Site (41WD46), a Middle Caddoan Occupation on the Sabine River, Wood County, Texas

The Carlisle site (41WD46) is located on the Sabine River near its confluence with Lake Fork Creek in the Upper Sabine River Basin. As defined by Perttula, the Upper Sabine River Basin includes the area from the headwaters of the Sabine River to the mouths of Cherokee Bayou and Hatley Creek at the western edge of the Sabine Uplift. Lake Fork Creek is one of several large south-southeastward flowing streams within the Upper Sabine River Basin. The town of Mineola is approximately 13 kilometers (km) west of the Carlisle site. The site is situated at the tip of an upland projection overlooking the Sabine River floodplain, but extends into the floodplain to within ca 30 meters of the river bank. The Lake Fork Creek channel is approximately one km east of the site. While the site was an improved pasture for many years prior to 1975 and to the present, it had been previously cultivated. In fact, this cultivation may have contributed to its initial identification in the early 1930s, as well as its subsequent partial burial. The upland sandy soils derive from the Queen City Formation, and these are highly susceptible to erosion and colluvial downwasting. Colluvial deposition seems to have been a prominent factor in the burial of cultural materials along valley margins and lower footslopes elsewhere in the Upper Sabine Basin, and the site's topographic position suggests that both alluvial and colluvial deposition is responsible for the burial of the floodplain cultural deposits at the Carlisle site.

Calcium concentrations in wetland groundwater in relation to water sources and soil conditions in the recharge area

Over the past several decades, vegetation communities in lowland wetlands in Western Europe have changed. Species-rich, low-productivity (i.e. low primary biomass production) communities characteristic of rich fens (fens characterized by microphilous species) have declined and are being replaced by vegetation communities characteristic of high-productivity rich fens, poor fens (fens characterized by ombrophilous species) and bogs. High concentrations of calcium in groundwater are generally believed to be an important controlling factor on the vegetation of rich fens Management for the protection of low-productivity rich fens therefore generally aims at conservation of calcereous groundwater conditions in the root zone of lowland wetlands. This paper relates the occurrence of calcium-rich groundwater in lowland wetlands of the Central Netherlands to water sources and soil conditions in the groundwater recharge area. The chemical composition of the following groundwater types is compared: groundwater recharged at a sandy ridge adjacent to the wetland area (ridge water); groundwater recharged by precipitation within the wetland (peat water); groundwater recharged by surface water in the wetland. Objective hydrological criteria are used to classify groundwater analyses according to recharge area. Oxygen-18 proved an essential criterion for the distinction between genetic groundwater types. It is therefore recommended to make oxygen-18 analysis standard procedure in geohydrological wetland research. Calcium concentrations are generally not suitable as tracers of different types of recharge areas. All groundwater types contain calcium. In contrast to what is generally assumed, lowest concentrations are observed in ridge water. Higher calcium concentrations are found in groundwater recharged in wetlands, especially in infiltrated surface water. Nutrient concentrations in both ridge and peat water are low, while those in infiltrated surface water are significantly higher. The main conclusion for nature conservation is that calcium-rich and mesotrophic conditions in the root zone can be realised not only by the seepage of groundwater from upland sandy recharge areas, as is generally thought, but also by the seepage of peat water. This is important as a severe deterioration in the quality of ridge water seeping upward on the river plain may be anticipated in the near future, which forms a threat to low-productivity rich fens. Peat water may offer an alternative water source for the conservation or regeneration of low-productivity rich fens.

CHANGES TO INFILTRATION AND INTERRILL EROSION FROM LONG-TERM PRESCRIBED BURNING IN LOUISIANA

: Effects of long-term prescribed burning on infiltration and interrill erosion were assessed on two longleaf pine-bluestem sites in Louisiana. Treatments represented biennially-applied winter, spring, or summer burning on an upland sandy loam site for 20 years; and annual winter or spring, and biennial winter or spring burns on a bottomland silt loam site for 10 years, with unburned controls. Immediate effects of burning were a reduction in surface cover, exposing soil to raindrop impact. Burning the sandy loam site increased interrill erosion after winter and spring treatments, but produced no immediate changes in infiltration capacity or time to runoff irrespective of treatment season. Rapid recovery of under-story vegetation mitigated soil exposure. Biennial burning did not increase interrill erosion, or reduce infiltration capacity and time to runoff on the sandy loam site after 20 years. A complete herbaceous understory covered the silt loam site two years after treatment. Interrill erosion was not significantly increased, or infiltration capacity and time to runoff decreased on burning treatments than unburned controls on the silt loam site. Litter biomass was important in predicting interrill erosion. No surface cover condition could be linked to variability in infiltration capacity. This study provides evidence for the resiliency of a longleaf pine-bluestem association to prescribed burning.

Studies on Maize‐Legume Intercropping and their Residual Effects on Soil Fertility Status and Succeeding Crop in Upland Situation

AbstractTo examine the advantages of cereal‐legume intercropping system with maize as main crops, field studies conducted for two years on sandy upland loamy soils in Bihar plateau, India, indicated maize‐groundnut as the best system. Yield advantages were noticed between 22–44 % over sole maize cropping. Different production indices largely indicated the same pattern in ranking intercropping treatments. Of the other legumes used, mung also showed potential whereas cowpea and soyabean did not. Increasing cropping intensities through use of interspace by legume did not significantly reduce maize yield, particularly in combination with groundnut and mung. Soil nitrogen enrichment through legume cultivation could be noted through examination of soil test values and yield of succeeding wheat crop. Wheat, however, did not show its promise as a follow‐up crop without input of water and fertilizer.

Management of an African floodplain: a contribution to the anthropology of public policy

Several hundred thousand smallholder households in Senegal and Mauritania are at risk from a large dam built at Mantali on the Bafing, the major tributary of the Senegal River. These households practise a complex set of production strategies sustaining a dense population in a Sahelian region. Despite low rainfall, in average years the area allows for two harvests, one dependent on summer rains on sandy upland soils and the other on post-summer floods on the alluvial plain. If the dam is managed as planned, it will adversely affect downstream production, income, and employment. Designed for hydropower, large-scale irrigation, and barge transportation, the dam would restrict the natural flood, causing: • -drastic reduction of recession cultivation; • -heavy reliance on costly irrigated production; • -decline in the quality of riverine pasture and in the numbers of stock that can graze during the long dry season; • -reduction in fish capture; • -transformation of the natural floodplain, reducing its capacity to support migratory birds and other wildlife; A delayed installation of turbines and an agreed controlled release from Manantali for at least 10 years provide an opportunity to examine the impacts of that release and to measure them against a potential reduction in hydropower and irrigation water.

Arthropod Footprints in the Sands of Time

Arthropod distribution in Florida's sandy uplands shows some obvious patterns. Arthropods endemic to Florida scrub are concentrated on the Lake Wales Ridge, apparently a long-term refuge. Scrub areas to the north apparently lost diversity, as some species that must have migrated through there from southwestern North America are now only in southern scrubs. The more recently formed Coastal Ridge was apparently colonized by the remnant fauna of north Florida, not by Lake Wales Ridge species. North Florida scrubs have few known endemics, but there are probably many endemics in sandhill habitats. Expansion and contraction of sandhill areas may explain some faunal patterns. Rapid destruction of Florida's upland habitats demands prompt research.

Rainfall irregularity and sowing strategies in Southern Mozambique

Rainfed crop production in the sandy uplands of the coastal zone of Southern Mozambique is very risky. Year-by-year fluctuations of rainfall are extremely wide and rainfall is very irregular. Precipitation is concentrated in the rainy period between October and April. People tend to spread sowing over a long period. This study aims to analyse yearly rainfall characteristics in the area in such a way that sowing strategies can be evaluated. The model SWETAM was developed to simulate yields for maize ( Zea mays) and sorghum ( Sorghum vulgare) for two stations in Southern Mozambique over a period of about 30 years. For every year, each month with sufficient rainfall was considered to be a sowing period and for the subsequent growing period the water-balance terms of crop and soil were calculated. Yield reduction as a consequence of water deficit was analysed. Results of the simulation indicate that, for rainfed agriculture, the environmental conditions are very risky. For each station, yields vary greatly from year to year. Plant density and depth of root zone seem to be important characteristics that influence water deficit and yield reduction under the prevailing meteorological conditions. From the subsistence farmer's point of view it seems rational to sow frequently over a long period. Their strategy for sowing is based upon a spreading of risks and short-term interests rather than upon maximizing production over a longer period. This may be the best way to secure the availability of a minimum of food every year, but it results in high losses of seeds.

An Example of Site Classification in the Southeastern Coastal Plain Based on Vegetation and Land Type¹

Abstract A site classification system based on vegetation and land type was developed for the Savannah River Plant (SRP) in the upper coastal plain of South Carolina. Different positions of the landscape support distinctive plant communities. Late successional plant communities and their immediate predecessors were identified on eight site types along a moisture gradient ranging from dry, sandy uplands to flooded bottoms. Late successional, near-stable plant communities, even in the highly disturbed forest ecosystems of the Southeast, act as integrators of environmental factors to reflectsite potential. Vegetation can supplement information on soils and topography in the delineation and classification of forest sites. Knowledge of site-vegetative relationships would be especially useful in making management decisions regarding wildlife habitat evaluation, hazard rating for insects, diseases, and fires, and estimating potential uses for recreation. Application of the system by practicing foresters is discussed. South. J. Appl. For. 11(1):23-28.

Multiple cropping in rainfed upland entisol under different soil management conditions in the sub-humid tropics

Field experiments were conducted for 2 years on a well drained upland sandy loam soil under rainfed conditions to study the effects of previous summer season crops of jute ( Corchorus olitorius L.) and direct seeded rice ( Oryza sativa L.) in unpuddled and unbunded soil followed by a short duration legume crop (rice bean ( Vigna umbellata (Thunb.) Ohwi and Ohashi) for forage or greengram ( Vigna radiata (L.) Wilczek) for grains) and fallow on the (i) productivity winter crops of barley ( Hordeum vulgare L.), lentil ( Lens esculenta Moench), field peas ( Pisum sativum L.), linseed ( Linum usitatissimum L.), mustard ( Brassica juncea (L.) Czern & Coss) and sunflower ( Helianthus annuus L.), (ii) soil profile moisture storage and (iii) its utilization. The winter crops were established with minimum (making sowing slots of 5 cm depth with a hand-drawn seed drill and without maintenance of mulch over surface) and conventional (four ploughings up to 15 cm depth with bullock drawn plough) methods of land preparation. The results revealed that compared to jute/fallow and jute/legume sequences, rice/fallow and rice/legume sequences resulted in higher soil moisture storage and, hence, a greater degree of seedling emergence per unit area, higher root weight and water use, and consequent higher grain yields and water use efficiency (WUE) of the subsequent winter crops. Winter crops yielded 17% more following direct seeded rice than after jute. Growing of short duration legume (rice bean or greengram) after jute or rice depleted stored moisture but increased yield and WUE of all winter crops. Grain yields of winter crops were 19% higher in tilled than in untilled soils. Under conventional tillage the soil moisture was slightly reduced at the time of sowing of winter crops but it resulted in increments in root weight, water use, grain yields and WUE of winter crops. WUE of barley was highest followed by field peas, which utilized more of soil moisture conserved at lower soil depths than other crops. Mustard gave the highest return (Rs.4663) followed by field peas (Rs.4603).

Structure and dynamics of jack pine stands near Elk Lake, Ontario: a multivariate approach

Multivariate techniques were utilized to examine even-aged jack pine stands on upland sandy sites at the southern edge of the boreal forest near Elk Lake, Ontario. Cluster analysis of 180 stands led to the recognition of 10 vegetation types, each showing a unique combination of floristics, physiognomy, and environmental components. Classification of common species led to the recognition of five ecological groupings, which show varying degrees of association with the vegetation types. Nonmetric multidimensional scaling of the stands suggested a vegetational continuum in response to overall moisture availability. A corresponding ordination of common species indicated the development of interspecific associations related to soil moisture conditions. It is suggested that the vegetational composition of upland jack pine forests is determined by both probabilistic and deterministic effects, and this is discussed in the context of vegetation structure and dynamics.

Dränwassergüte und Nährstoffaustrag im nordwestdeutschen Raum auf Marsch, Moor und Geest

Dränwassergüte und Nährstoffaustrag im nordwestdeutschen Raum auf Marsch, Moor und Geest

Litter-Fall Patterns within a Floodplain Forest

Litter-fall patterns were examined for 3 years within a floodplain forest on the upper coastal plain of South Carolina. Average annual leaf fall and total litter fall ranged from 415-538 g-m-2.year-1 and 570-667 g-m-2-year-1, respectively, across the floodplain habitat. These values were similar to those of other alluvial habitats and exceeded the litter-fall totals reported for nonwetland, warm-temperate, deciduous forests. Leaf fall increased across the floodplain from stream bank to upland forest. Leaf fall varied from 73-84%o of total litter fall which exceeds the worldwide average of 70%o. Woody litter fall decreased across the floodplain whereas reproductive inputs remained similar. Nutrient return (Ca> N > K> Mg) in leaf fall was relatively high, particularly for the less mobile elements (Ca, Mg). Calcium and Mg inputs in leaf fall increased from bank to upland terrace. Leaf fall inputs of N and K were reduced on the sandy upland where soil leaching potential is greatest. Translocation may minimize nutrient return of N and K on the upland, whereas fluvial subsidies of these nutrients would compensate for potential losses within the alluvial floodplain habitat. Our results support the contention that leaf fall and nutrient return in litter are higher in forested wetlands receiving fluvial subsidies than in most nonwetland, deciduous forests. INTRODUCTION The available information on litter-fall inputs to terrestrial ecosystems indicates geographic patterns which are correlated with particular environmental factors (Bray and Gorham, 1964; Jordan, 1971; Jordan and Murphy, 1978; Meentemeyer et al., 1982). Litter production rates generally increase latitudinally from Arctic to tropics in conjunction with total light availability during the growing season (Jordan and Murphy, 1978) and total actual evapotranspiration (Meentemeyer et al., 1982). Leaf fall accounts for approximately 70% of total litter fall in different ecosystems worldwide (Meentemeyer et al., 1982). These overall patterns have usually been derived from a single year's estimates and therefore preclude considerations of annual variations in litter-fall rates and composition (Sykes and Bunce, 1970). Litter-fall patterns in wetland forests are usually not included in geographical determinations. However, recent evidence indicates that litter production in forested wetlands often exceeds corresponding values for nonwetland habitats (Bell et al., 1978; Brinson et al., 1980; Gomez and Day, 1982). Many wetlands receive fluvial inputs of water, oxygen and nutrients which can increase nutrient cycling and productivity (Brinson et al., 1980). Primary productivity and litter production are often higher in flowingwater than still-water wetlands which lack these fluvial inputs (Schlesinger, 1978; Brinson et al., 1980; Gomez and Day, 1982; but see Brown and Peterson, 1983). The extent and timing of flooding may thus affect wetland litter production and the import-export dynamics (Post and de la Cruz, 1977) of allochthonous litter sources within watershed units. The present study was conducted to determine litter-fall patterns in a floodplain forest surrounding a blackwater stream on the coastal plain of South Carolina. We were interested in assessing spatial and temporal changes in litter-fall components across the floodplain from stream bank to adjacent upland terrace forest. The study was continued for several years to determine the annual variations in litter-fall production at different points along the flood frequency gradient. METHODS The study was conducted in a floodplain along Lower Three Runs Creek (LTRC)

The organization of macroinvertebrate communities in the major tributaries of the LaTrobe River, Victoria, Australia

SUMMARY. Seventeen sites were each sampled six times over 2 years for macroinvertebrates. A range of physicochemical variables was also measured to determine which factors were related to the distribution of species. Numerical classification of the faunal data indicated that four groups of sites or communities were distinguishable: lowland sites; sandy upland sites; cobble upland sites from the northern catchment; cobble upland sites from the southern catchment. Multiple discriminant analysis and multiple regression analysis demonstrated that particle size of the sediment, concentration of dissolved ions and altitude were the physicochemical features that were most strongly associated with changes in the faunal distribution. Abundances of shredders and predators did not vary between the site groups while those of scrapers, gatherers and filterers did: scrapers were most abundant at cobble sites while gatherers and filterers were least abundant on sand and increased in abundance downstream. The distribution of the feeding groups showed some similarity with that predicted by the River Continuum Concept, but the fact that the shredders did not decrease in abundance downstream was a notable difference. Abundance of the total fauna at a site was inversely related to the amount of benthic organic matter. This feature is contrary to the pattern usually reported from rivers in the northern hemisphere.

Asymbiotic N2-fixing bacteria associated with three boreal conifers

Azotobacter spp., Azospirillum spp., and Desulfovibrio spp., were identified as the predominant nitrogen-fixing bacteria associated with seedling root sections collected from natural stands of Pinusbanksiana Lamb., Piceamariana (Mill.) B.S.P., and Larixlaricina (Du Roi) K. Koch growing in Alberta. Samples from the sandy upland habitat of P. banksiana exhibited lower average rates of nitrogen fixation relative to the wet lowland occupied by P. mariana and L. laricina. Average nitrogen-fixing capacity (by acetylene reduction) was greater among bacteria isolates from L. laricina than those from P. mariana. Azospirillum spp. were strongly associated with P. mariana, while Azotobacter spp. were isolated more frequently from L. laricina.

Goshen Springs: Late Quaternary Vegetation Record for Southern Alabama

The sediments of Goshen Springs, Pike County, Alabama, USA, provide a late Quaternary biostratigraphic record that extends from the Altonial Substage of the Wisconsinan Glacial Stage to the present. Diagrams showing percentages of palynomorphs and concentrations of plant macrofossils permit the reconstruction of both local and regional vegetation. At Goshen Springs, a drying trend during the Altonian Substage (>28 000 yr BP) resulted in the replacement of mesic—temperate forests by southern pines, oaks, and hickories. Climatic conditions of warmth and summer drought favored oak—hickory—southern pine forests from 26 000 yr BP in the mid—Farmdalian substage, through the full glacial and late glacial, until the mid—Holocene (5000 yr BP). During the full glacial, a strong climatic gradient and major vegetation ecotone extended across central Alabama and Georgia, separating northern boreal—like forests of spruce and jack pine from warm—temperate oak—hickory—southern pine forest on the Gulf Coastal Plain. The Goshen Springs record documents the persistence of many warm—temperate deciduous and broadleaf evergreen tree taxa in southern Alabama through the full and late glacial. The early Holocene forests, dominated by oak and hickory, were replaced by widespread southern pine forest on the sandy uplands of the Gulf Coastal Plain about 5000 yr ago. During the mid—Holocene, the attainment of the present climatic regime, characterized by abundant precipitation throughout the growing season, and the return of sea level to near—modern position resulted in the establishment of the southern pine forests and of widespread swamps and marshes in the Gulf and Southern Atlantic Coastal Plains.

SPECIES RESPONSE TO A MOISTURE GRADIENT IN CENTRAL ILLINOIS FORESTS

Polar and Gaussian ordination applied to data collected from 37 forest sites in central Illinois resulted in a continuous and gradual change in species composition along a moisture gradient. A series of overlapping species success curves formed by plotting Importance Values over stands ordered along the gradient varied continuously in modal location and habitat width. Blackjack oak and black oak dominated upland sandy sites. Black oak, white oak, and shagbark hickory were the most important species on exposed, upper slope positions or ridge tops with silt‐loam soils. Red oak, sugar maple, American elm, and bur oak dominated sheltered locations on lower slope positions and stream terraces. Sycamore, silver maple, and cottonwood were leading tree species in floodplain forests. Conversion of black, white, and red oak forests on silt‐loam sites to sugar maple, white ash, and red elm dominance is evident by high densities of these shade tolerant species in the understory. Composition of forests at the extreme ends of the moisture gradient is more stable than the mesic sites. Maximum tree diversity occurred on mesic sites and decreased toward the extreme ends of the moisture gradient. However, competitive exclusion of shade intolerant species by sugar maple and other species has caused a decrease in understory diversity on mesic sites. Diversity decreased from canopy to understory strata in lowland forests and increased on xeric sites.

Species Response to a Moisture Gradient in Central Illinois Forests

Polar and Gaussian ordination applied to data collected from 37 forest sites in central Illinois resulted in a continuous and gradual change in species composition along a moisture gradient. A series of overlapping species success curves formed by plotting Importance Values over stands ordered along the gradient varied continuously in modal location and habitat width. Blackjack oak and black oak dominated upland sandy sites. Black oak, white oak, and shagbark hickory were the most important species on exposed, upper slope positions or ridge tops with silt-loam soils. Red oak, sugar maple, American elm, and bur oak dominated sheltered locations on lower slope positions and stream terraces. Sycamore, silver maple, and cottonwood were leading tree species in floodplain forests. Conversion of black, white, and red oak forests on silt-loam sites to sugar maple, white ash, and red elm dominance is evident by high densities of these shade tolerant species in the understory. Composition of forests at the extreme ends of the moisture gradient is more stable than the mesic sites. Maximum tree diversity occurred on mesic sites and decreased toward the extreme ends of the moisture gradient. However, competitive exclusion of shade intolerant species by sugar maple and other species has caused a decrease in understory diversity on mesic sites. Diversity decreased from canopy to understory strata in lowland forests and increased on xeric sites.

Presettlement Magnolia‐Beech Climax of the Gulf Coastal Plain: Quantitative Evidence From the Apalachicola River Bluffs, North‐Central Florida

The presettlement vegetation mosaic bordering the Apalachicola River in the Panhandle of Florida, reconstructed from General Land Office Survey records of 1824—1825, consisted of upland pine—oak forest, open pine flatwoods, mesic hardwood hammock, tributary stream hardwoods, and Apalachicola floodplain swamp. Longleaf pine forest interspersed with blackjack, red, and post oaks occupied the sandy uplands east of the Apalachicola River. Alluvial terraces west of the river supported pine stands probably dominated by longleaf and slash pines. The mesic hammock forest of the river bluffs was comprised of an admixture of hardwood species, dominated by magnolia and beech. The tributary bottomlands community consisted primarily of bay, holly, and beech; the Apalachicola floodplain forest was dominated by bay, gum, and oak. The magnolia—beech forest of the Apalachicola River bluffs represents the second mesic upland magnolia—beech forest quantitatively documented for the original vegetational of the Gulf Coastal Plain and is the first such record for Florida. The concept of the magnolia—beech climax forest is reinstated here for the original vegetation of the southern Gulf and Atlantic coastal plains (the region of overlap in distributions of Magnolia grandiflora and Fagus grandifolia). Modern forest—management practices that include fire suppression and selective lumbering are causing both a shift from pine to hardwood dominance on sandy upland sited and a change from magnolia—beech to mixed hardwood dominance on mesic sites throughout the southern coastal plains. The "southern mixed hardwood forest climax" (sensu Quarterman and Keever 1962) thus represents a converging trend of modern and future vegetation of the South toward a new climax different from that existing in the presettlement vegetation.