Rainfall In June Research Articles

Comparison of Aerially-Applied Gypchek Strains Against Gypsy Moth (Lepidoptera: Lymantriidae) in the Presence of an Entomophaga maimaiga Epizootic

The standard strain (LDP-226) of Gypchek®, a nucleopolyhedrovirus product registered by the USDA Forest Service against the gypsy moth, Lymantria dispar (L.), was compared against a strain, LdMNPV-203NL (NL = nonliquefying), that was developed for production in cell culture. Both strains were applied by air to U.S. government property in Prince Georges Co., MD, in early May 2003 at the rate of 1 × 1012 occlusion bodies per ha. The two goals of the study were (1) to compare the first and second wave effects of the two strains against gypsy moth populations; and (2) to delineate the combined effects of the applied virus and the expected epizootic of the gypsy moth specialist fungal entomopathogen Entomophaga maimaiga Humber, Shimazu, and Soper. Heavy rainfall in May and June preceded a massive epizootic of E. maimaiga, whose effects did not mask the first wave of viral mortality. When the effect of application sequence was considered, it was concluded that the two strains were equivalent in their first-wave impacts. High fungal-induced mid and late-season gypsy moth larval mortality suppressed the second wave of virus at all evaluation sites. There were no obvious differences in the second waves engendered by the two LdNPV strains in the greatly reduced late-instar larval population.

Sensitivity of the Simulated Monsoons of 1987 and 1988 to Convective Parameterization Schemes in MM5

AbstractIn this study the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) version 3.5.2 was used to simulate the Indian summer monsoon during the two contrasting years of 1987 and 1988, a dry year and a wet year, respectively. Three different convection parameterization schemes of Betts–Miller–Janjic, Kain–Fritsch, and Grell were used to study the sensitivity of monsoon to cumulus effects. The model was integrated for a period of 6 months, starting from three different initial conditions of 0000 UTC on 1, 2, and 3 May of each year using the NCEP–NCAR reanalysis data as input. The 6-hourly reanalysis data were used to provide the lateral boundary conditions, and the observed weekly Reynolds sea surface temperature, linearly interpolated to 6 h, was used as the lower boundary forcing. The results show that all three cumulus schemes were able to simulate the interannual and intraseasonal variabilities in the monsoon with reasonable accuracy. However, the spatial distribution of the rainfall and its quantity were different in all the schemes. The Grell scheme underestimated the rainfall in both the years. The Kain–Fritsch scheme simulated the observed rainfall well during July and August, the peak monsoon months, of the year 1988 but overestimated the rainfall in June and September of 1988 and throughout the monsoon season of 1987. The Betts–Miller–Janjic scheme simulated less rainfall in the drought year of 1987 and overestimated the rainfall in June and July of 1988. The circulation patterns simulated by the Betts–Miller–Janjic and Kain–Fritsch schemes are comparable to the observed patterns.

On some characteristic features of daily rainfall over Madhya Maharashtra

Information in processed form, is often needed to meet the demands in agriculture, hydrology and other water-related human activities. In this context, daily rainfall continue to be of prime importance since it is the daily rainfall which, when accumulated gives weekly, monthly or seasonal totals. This paper deals with some of the characteristic features of daily rainfall at nine selected stations in Madhya Maharashtra. The study is based on daily rainfall data of June to September months for 10 years (1991-2000).
 Depending upon rainfall amounts (or lack of it), a day has been categorized as rainy day, drizzle day or dry day. Making use of the concept of evapotranspiration, rainy day has been further divided into crop rainy day. Distribution of these various classes of days, their contribution to monthly totals and relationship among them, have been obtained and discussed. The rainy days have been used to obtain mean daily rainfall intensity and its association with monthly rainfall, examined through a series of regression equations. Frequency of heavy falls i.e., rainfall exceeding 25 mm in a day have been determined and its contribution to monthly rainfall, evaluated.
 There seems to be a tendency for the rainy days and the rainfall to be below normal in recent years. Perfectly dry weather could prevail nearly half of June and July months over the region. Heavy rainfall contributes substantially to the monthly total. During June and September mean daily rainfall intensity is perhaps weakly related with the monthly rainfall.

Atmospheric water vapor transport associated with typical anomalous summer rainfall patterns in China

This paper attempts to reveal the atmospheric water vapor transports associated with typical anomalous summer rainfall patterns in China. The results show that origins of water vapor supply related to anomalous rainfall patterns are different from those related to the normal monsoon rainfall. Anomalous pattern 1, with a heavier rainbelt along the middle and lower reaches of the Yangtze River valley, follows from a convergence of the tropical southwest water vapor transport with the midlatitude northeast water vapor transport; the tropical water vapor transport comes directly from the Bay of Bengal and the South China Sea but originally from the Philippine Sea. The anomalous water vapor transport is associated with a southwestward extension of the western Pacific subtropical high and a southward shift of the upper East Asian jet stream. Anomalous pattern 2, with a main rainbelt along the Huaihe River valley, is supported by the convergence of the subtropical southwest water vapor with the midlatitude water vapor transport. The subtropical branch comes directly from the South China Sea but originally from the East China Sea and the adjacent subtropical Pacific to the further east along 20–25°N. The background large‐scale circulation change includes a northwestward extension of the western Pacific subtropical high and an eastward shift of the upper jet stream. Although the cross‐equator flows including the Somali jet supply abundant water vapor for the normal condition of June, July, and August rainfall over China, the tropical water vapor transports related to typical anomalous rainfall anomalies originate from the tropical western Pacific Ocean. The northward transport of anomalous warm water vapor occurs mainly in the lower troposphere, while the transport of midlatitude cold water vapor occurs briefly in the upper troposphere.

Taking a (mosquito) bite out of malaria

Early in the last decade, great strides were made toward eliminating malaria through the use of pest control and extermination of mosquitoes, which are responsible for transmitting the infectious Plasmodium parasites that cause the disease. Malaria was once prevalent in the US and Europe, but the draining of wetlands and improved sanitation eliminated the scourge from these affluent regions. Today, most deaths from the disease occur in poor, rural areas of Africa, where malaria incidence is on the rise, killing more than one million people each year, most of whom are young children. This statistic seems shocking considering the disease’s preventability by relatively simple means, such as mosquito netting and prophylactic drugs such as quinine and its derivatives. Unfortunately, pharmaceutical treatment is costly, in short supply, and rendered ineffective as more virile strains of the disease become resistant to the medication, so malaria prevention is widely considered a top priority. As a first line of defense, the United Nations Children’s Fund recommends the wide distribution of mosquito nets impregnated with insect repellents as the most cost-effective disease prevention method. Many international health organizations have now donated millions of dollars for the production and allocation of insecticide-treated nets. The United Kingdom’s Department for International Development’s $3 million donation will provide 400,000 of these nets to pregnant women and children less than 5 years of age in Zimbabwe, where malaria is the second-highest killer of young children. Japan, in an unprecedented contribution, has promised 10 million bed nets to Africa by 2007. The Global Fund, through US sponsorship, began a $22 million, 5-year plan to fight malaria in 2003 at the urging of Swaziland, Mozambique, and South Africa. According to the Global Fund, the efforts have “tripled the area of operations in Mozambique.” The US pledges at least $2 billion more through 2008. The WHO’s Roll Back Malaria Department has attempted to strike preemptively by initiating the Malaria Early Warning System, which began monitoring rainfall in June 2002. Rainfall in warm, semi-arid and desert-fringe regions can trigger explosive epidemics by providing fertile breeding grounds for mosquitoes. By studying rainfall data, the organization is able to identify regions at risk for a future epidemic, and assistance can arrive before the outbreak occurs. On the clinical front, technological advances have paved the way for new means of malaria prevention. Using the recently decoded genomes of both the carrier mosquito and the dangerous parasite it spreads, scientists hope to exploit sequences that might belie weaknesses in the genetic makeup of the organisms in order to disrupt the life cycle of the deadly protozoan. Researchers have already found genes that can be manipulated to help produce more effective repellents and insecticides. Theoretically, the pests themselves can be genetically altered to resist malaria, but that idea invites controversy, with the possibility of genetic mixing among mosquito species perhaps creating an even stronger malaria carrier. Controversy aside, the world is witnessing an increasing effort to eradicate the disease by boosting prevention measures and identifying new treatment options. The alarming number of child-related deaths from this wholly treatable illness has signaled the urgency to treat malaria on a global scale. The donations by world bodies, innovative research by both public and private organizations, and new advancement in technology represent fresh hope.

Corn Production on a Subsurface‐Drained Mollisol as Affected by Fall versus Spring Application of Nitrogen and Nitrapyrin

Nitrogen management strategies that affect corn (Zea mays L.) production and loss of NO3–N to subsurface, tile drainage often include decisions of when to apply N (fall or spring) and whether to use a nitrification inhibitor. A field study was conducted from the fall of 1993 through 2000 on a tile‐drained Canisteo clay loam [fine‐loamy, mixed (calcareous), mesic Typic Endoaquolls] to determine the influence of fall vs. spring application of N and nitrapyrin [2‐chloro‐6‐(trichloromethyl) pyridine] on yield of corn and soybean [Glycine max (L.) Merr.] in rotation. Four anhydrous ammonia treatments [fall without nitrapyrin (NP), fall with NP, spring preplant without NP, and spring with NP] were replicated four times and applied at 134 kg N ha−1 (120 lb acre−1) for corn each year. Fall applications occurred between 20 October and 1 November when soil temperatures generally were ≤10°C. Six‐year average corn grain yields were least for fall N without NP [10.10 Mg ha−1 (161 bu acre−1)] and greatest for fall N with NP [10.72 Mg ha−1 (171 bu acre−1)], spring N without NP [10.82 Mg ha−1 (172 bu acre−1)], and spring N with NP treatment [11.03 Mg ha−1 (176 bu acre−1)]. Year‐to‐year variation in yield response to the treatments was great and was characterized by above‐normal May rainfall affecting the performance of the fall treatments while above‐normal June rainfall affected both fall and spring treatments. Apparent N recovery ranged from 47% for fall N without NP to 61% for spring N with NP. Annual economic return to fertilizer was greatest for spring N with or without NP. Based on the dominating effect of spring rainfall, this study suggests growers consider a spring preplant N strategy either with or without NP as an alternative to fall N for greatest economic return and least N loss to the environment on these Mollisols.

Atmospheric circulation characteristics during some El-Nino years in relation to Indian summer monsoon rainfall

Based on observed rainfall data of India Meteorological Department (IMD), correlation coefficients (CCs) have been computed between Indian summer monsoon rainfall (ISMR) and sea surface temperature (SST) anomalies over different Nino regions and standardised pressure difference between Tahiti and Darwin. Significant positive CCs are found between the Southern Oscillation Index (SOI) in winter and subsequent June rainfall over India. Concurrent with and subsequent to Indian summer monsoon, SOI shows significant positive CC with the mean rainfall of July to September (JAS). Significant negative CCs are found between JAS mean rain and the concurrent and following SST anomalies over Nino-3.4 region. On the basis of these correlations, it is proposed that the entire period of summer monsoon from June to September could be divided into two sub-periods such as: early summer (June) and mid-late summer (July to September) monsoon for prediction of ISMR in the extended range. In order to examine the characteristics of atmospheric circulation during some El-Nino years, divergent flow at 200 hPa and omega field at 500 hPa based on NCEP/NCAR reanalysis have been studied in detail. Major significant southward shift of upper level divergent field from India are related to El-Nino and this shift may be responsible for causing droughts during several El-Nino years over India. Also vertical wind fields at 500 hPa show sinking motion over large parts of India and west Pacific and ascending motion over southern Indian Ocean, central and eastern Pacific during major drought years.

Agricultural impacts of large-scale variability of the West African monsoon

Agriculture in the Sudano-Sahelian zone is heavily dependent on the seasonal characteristics of rainfall. This study seeks to characterise components of regional climatic variability and their impact on simulated, attainable, plot level yields of millet. First we describe at a regional scale two main events in the seasonal pattern of the monsoon over West Africa by using a daily rainfall dataset over the 1968–1990 period, that is, (i) the onset of the summer monsoon characterised by an abrupt northward shift of the ITCZ from 5°N to 10°N around 24 June, and (ii) large and coherent intra-seasonal rainfall fluctuations at two different time scales, around 15 and 40 days. Second, we investigate the impact of these regional phenomena on local crop yields using SARRAH, a crop model simulating attainable yield, i.e. water and climate limited but not nutrient limited yield, by means of sensitivity analyses. The response of attainable yield to sowing date is studied for 19 years of the 1968–1990 period for a 90-day millet crop at Niamey. The results indicate that information on regional climate dynamics might help improve crop production locally. It is shown that the regional onset of the monsoon is very close to the ideal sowing date, derived from simulations, at Niamey and that simulated yields are much higher for these dates than for those identified with the traditional rule based on local rainfall. Taking into account the regional onset of monsoon thus seems to improve the relationship between water available and water used by the plant, and thus seems to potentially increase crop water use. Where attainable, simulated yields using the monsoon onset criterion are low, they are generally caused by intra-seasonal dry spells that have differential impact depending on phenological stage of the crop.

On Climate Variations and Changes Observed in South Korea

This study describes observations on possible climate changes occurring on the Korean Peninsula. We found that in large urban and industrial areas in Korea, there has been a significant increase in the annual mean temperatures according to data of the past 29 years. The increase in January temperatures was in the order of 0.8 ∼ 2.4 ° C. However, in rural and marine stations, the increase in annual mean temperature was 0.6 ° C; the level of the global average. There was also an increase in precipitation: 259 mm over the recent 97 years. Observation has revealed that a month-long steady rainfall in late June and July with a quasi-stationary polar front has not occurred in recent years and has been replaced with scattered convective heavy-showers on a local scale in July and August. It is observed that the behaviour of this rainy front, `the Changma front' has brought changes to rainfall characteristics. Our results highlight the importance of the shortened rainy season. However, the amount of rainfall and the number of heavy rainfall days have increased.

Linkages between coastal runoff and the Florida Keys ecosystem: A study of a dark plume event

Using data collected by satellite sensors, rain and river gauges, and ship surveys, we studied the development and wind‐driven transport of a dark water plume from near Charlotte Harbor, Florida, to the Dry Tortugas in the Florida Keys in mid‐October 2003. MODIS and SeaWiFS imagery showed that the patch contained an extensive (∼5,500 km2) phytoplankton bloom that formed originally near the central coast of Florida. The data linked the bloom to high nutrient coastal runoff caused by heavy rainfall in June and August. Total N and P required for the bloom, which may contain some Karenia brevis cells, was estimated to be 2.3 × 107 and 1.5 × 106 moles, respectively. The dark color became increasingly dominated by colored dissolved organic matter, toward the Dry Tortugas, where CDOM absorption coefficients (0.08–0.12 m−1 at 400 nm) were 2–3 times higher than the surrounding shelf waters, while chlorophyll and inorganic nutrients decreased to negligible levels.

Climate Prediction for Brazil's Nordeste: Performance of Empirical and Numerical Modeling Methods

Abstract Comparisons of performance of climate forecast methods require consistency in the predictand and a long common reference period. For Brazil's Nordeste, empirical methods developed at the University of Wisconsin use preseason (October–January) rainfall and January indices of the fields of meridional wind component and sea surface temperature (SST) in the tropical Atlantic and the equatorial Pacific as input to stepwise multiple regression and neural networking. These are used to predict the March–June rainfall at a network of 27 stations. An experiment at the International Research Institute for Climate Prediction, Columbia University, with a numerical model (ECHAM4.5) used global SST information through February to predict the March–June rainfall at three grid points in the Nordeste. The predictands for the empirical and numerical model forecasts are correlated at +0.96, and the period common to the independent portion of record of the empirical prediction and the numerical modeling is 1968–99. O...

An experimental study of the effects of predation on the breeding productivity of capercaillie and black grouse

Summary The capercaillie Tetrao urogallus and black grouse Tetrao tetrix are declining in the UK, and low breeding success has been identified as the key factor in the decline of the former. To investigate possible causes, breeding productivity was studied in relation to predation, weather, vegetation changes and deer numbers over an 11‐year period (1989–99) within native pinewood at Abernethy Forest, Scotland. The abundance of predators (crows Corvus corone and red foxes Vulpes vulpes) was experimentally manipulated in 1992–96 by culling. Productivity (chicks reared per female) was compared between forests with and without experimental predator management. During predator control, the number of breeding crows was reduced from 10 pairs to one. The attempted reduction in red fox abundance was unsuccessful; only small numbers of adults were killed, and neither scat nor den counts declined significantly. Predation on artificial nests containing six hen eggs and a hen egg filled with wax was measured as an index of predator activity from 1991 to 1999. Predation was lowest during the last three years of predator control, 1994–96. Predators could sometimes be distinguished by signs on depredated eggs. Predation on artificial nests by crows was highest during 1991–93. However, after predator removal stopped in 1997 few crows returned, and increased predation on artificial nests did not involve increased signs of crow predation. Pine marten Martes martes numbers increased during the study period and became significant predators of artificial nests. The total number of capercaillie eggs and nests depredated by crows was estimated from the number of depredated capercaillie eggs found and the proportion of crow‐predated hen eggs in artificial nests. The values ranged from 18 to 158 eggs over 3 years, equivalent to 3–23 capercaillie nests year−1. Capercaillie productivity was low (< 1 chick per female) during 1989–93 and 1997–99 but higher during 1994–96. Compared with nine other forests in Scotland, changes in capercaillie productivity at Abernethy were different. Productivity at Abernethy was negatively related to June rainfall, and to the minimum daily predation rate on artificial nests by crows. There was also a significant interaction in that capercaillie were most productive when low rainfall coincided with low predation by crows on artificial nests. The productivities of black grouse and capercaillie were positively correlated, but greater in the former. As in capercaillie, black grouse productivity was negatively related both to June rainfall and the minimum daily predation rate on artificial nests by crows, and there was an interaction. Synthesis and applications. The long‐term increase in crows and red foxes and the predicted increase in rainfall in Scotland may have negative effects on capercaillie and black grouse. In the short term, control of crows is likely to improve productivity. In the long term, increased woodland size and some reversal of fragmentation might decrease the access to woodland of predators associated with the interface between farmland and woodland.

Design of a Regional Climate Model for the Simulation of South China Summer Monsoon Rainfall

The objective of this study is to modify a regional climate model (RCM)—the Regional Climate Model of the National Climate Center of China—to simulate the summer monsoon rainfall over South China and the South China Sea. Such a modification is necessary because this RCM was designed for studying the climate over central and north China where precipitation processes are very different from those occurring further south so that simulations using the basic parameters of the original model give precipitation amounts much less than those observed.Using the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data, many sensitivity experiments have been carried out for the months of April to June 1998, which include modifying the cumulus parameterization scheme, the large-scale precipitation scheme, the radiation scheme, the surface exchange processes, and the size of the buffer zone. The design of all the experiments is either to enhance the moisture provision to the atmosphere over South China and the South China Sea, or to help the model atmosphere realize the moisture to form precipitation. It is found that indeed modifications to the various parameters can produce rainfall amounts much closer to those observed.Based on the results of these experiments, an “optimal” design of the RCM is reached and tested for its effectiveness using the NCEP reanalyses for two wet years (1994 and 1997) and two dry years (1996 and 1999) during which rainfall in May and June over South China were above/below normal respectively. The physical processes in this design include the Kuo scheme for convective precipitation, the Pal scheme for large-scale precipitation, the Holtslag scheme for the planetary boundary layer, the radiation transfer scheme of the NCAR Community Climate Model Version 3, and the Biosphere-Atmosphere Transfer Scheme for the land surface process. The width of the buffer zone is reduced and the effective cloud droplet radius is fixed at different values over land and ocean. The neutral drag coefficient is prescribed as a function of surface wind speed, and the heat and moisture exchange coefficients are set at values larger than that of momentum. The simulations based on this design for all the five years are found to be much closer to observations than those from the control.

A Study on Relationship Between the Seed Crop in the Chinese Fir Orchards and Meteorological Factors

Chinese fir (Cunninghamia lanceolata) is recognized as a highly produc tive, valuable tree species in the sub_tropical region of China. Chinese fir is monoecious, and self_fertilization is possible because time of pollen dispersal and seed cone receptivity overlap on the same tree. Since 1980s, 3 500 hm 2 s eed orchards of Chinese fir have been established, in order to provide lots of super ior seeds for the plantations. However, it takes about two_years from flower di fferentiation (from axillary buds of current_year lateral shoots) to seed matur ity. Many factors affect the seed crops during the flower differentiating, polli nation and seed development phases. As a result, master years vary from region t o region, and a good seed crop generally occurs every 2_3 years. In this case, t he managers of the seed orchard meet a lot of challenges to manage the seed orch ard of Chinese fir well. Based on the data of annual seeds crop of Chinese fir o rchards and corresponding meteorological factors collected from four forestry fa rms of Xitian, Anhui province; Yangkou and Guanzhuang, Fujian province; Xiaokeng, G u angdong province respectively, the Step Regression Analysis between seeds crops and 20 meteorological factors during anthesis, pollination and pubera was conduc ted so that the key factors to affect the seed crop would be detected. Furthermo re, the phenomena and meteorological reasons for the cycle of good and poor seed s year in Chinese fir orchards were also discussed. The results showed that ther e existed the phenomena of the fruiting cycle in the orchards of Chinese fir for different ages and various growth zones, and the cycle is 2_3 years rather than 4_5 years. Rainfall and sunlight during pollination and pubera affected the fru iting cycles significantly. When these two factors are abnormal, the pollination in the Chinese fir orchard was hindered. Although it changes with environment o f orchards, clones and density of orchards, the cycle is closely related with me teorological factors especially in March (pollination period). The changes of th e cycle will be more dramatic when rainfall and sunlight in June and July are un favourable for young cone development. It would be a good seed year if the weath er conditions are favourable both for pollination and pubera phrase, otherwise i t would be a poor seed year. At the same time, the suggestions to solve the pro blem of the fruiting cycle in Chinese fir orchards were discussed in the paper.

Simulated weather variables effects on millet fertilized with phosphate rock in the Sahel

The Sudano–Sahelian agroecological zone is characterized by low and variable rainfall regimes and P deficiency. The present study complements previous research efforts and the objective was (i) to use the Newhall Simulation Model (NSM) to characterize three ICRISAT research sites, and (ii) to use output of NSM to develop an empirical model to guide efficient use of rainfall and fertilizers. The results show that length of the periods that rainfall exceeded evapotranspiration was larger in Bengou than in Gobery and Sadore. Total positive moisture balance during the three growing seasons was 85.7 mm at Bengou and 19.7 mm at Sadore. The model explained 52% of the variability in millet yields based on curvilinear response to P fertilizer, standardized May–June (Rmj) rainfall, and the number of wet days in the year (BW3). Yields appear more sensitive to BW3 than to Rmj. Their respective elasticity coefficients (Ec) were 0.62 and 0.09. Assessment of the model using R2=0.76 and the D-index = 0.85 showed reasonable agreement between model estimation and actual field yields. The study demonstrates the application of simulation models as a cost-effective means in terms of time and funds to agronomic research.

Long-term effect of nutrient management and rainfall on pod yield of groundnut (Arachis hypogaea) in groundnutbased cropping systems

A field experiment was conducted from 1999 to 2008 on fixed site at the research farm of Directorate of Groundnut Research, Junagadh (Gujarat) to develop a sustainable nutrient management schedule for groundnut ( Arachis hypogaea L.)based cropping systems, and to find out the influence of seasonal rainfall on pod yield of groundnut. Combination of 14 treatments of inorganic nutrients (100% RDF and 50% RDF) and farmyard manure (5 t/ha) were applied to groundnut and the component crops of groundnut-wheat and groundnut-wheat [ Triticum aestivum (L.) emend. Fiori & Paol]-greengram [ Vigna radiata (L.) Wilczek] cropping systems. Integrated use of or- ganic and inorganic nutrients (FYM 5 t/ha+50% RDF) to kharif groundnut recorded significantly higher pod yield (1,037 kg/ha) and the total system productivity in terms of groundnut equivalent yield (2,187 kg/ha) over the use of inorganic nutrients. This combination also recorded higher sustainable yield index and predictability over the use of inorganic nutrients across the experimental period. Among cropping systems, the total system productivity was significantly higher in groundnut-wheat-green gram cropping systems 2.34 + GPEY/ha with the integrated use of organic and inorganic nutrients. The rainfall in June had a significant effect on pod yield of groundnut when sup- plied with both organic and inorganic nutrients (FYM 5 t/ha+50% RDF). Depending upon the amount and period, rainfall received in the months of June and July had a positive effect on pod yield of groundnut, however, August and September rainfall showed negative effect.

Autumn and Spring Drought Periods Affect Vegetation on High Elevation Rangelands of Turkey

The amount and temporal distribution of precipitation received is of critical importance for regrowth and plant production on rangelands. The effects of drought in the autumn, and spring/summer, as they affected sheep fescue (Festuca ovina L.) dominated vegetation in Eastern Anatolia, Turkey, were examined between 1996 and 1998. Artificial drought was created using polyethylene rain-out shelters. The experiment was a randomized complete block design with 3 replications with a split-plot arrangement of treatments. Main plots included 2 autumn treatments: imposed artificial autumn-drought or a 40 mm of additional water plus rain. Sub-plots contained 4 treatments: artificial drought in May, June, July, or full spring rainfall. The number of reproductive shoots, aboveground biomass production, protein content, protein yield, canopy coverage and botanical composition were determined. Reproductive shoot numbers were reduced from 617 to 31 m(-2) when plants entered winter without autumn regrowth as a result of autumn-drought. Plots subjected to drought in the autumn had aboveground biomass of 424 kg ha(-1). Protein content of forage, crude protein yield and water use efficiency (WUE) were 11.6%, 49 kg ha(-1) and 1.5, respectively. These were compared with 1,038 kg ha(-1), 9.6%, 99 kg ha(-1), and 2.4, respectively, for plots received normal autumn precipitation in addition to 40 mm of additional water. Aboveground biomass production increased as short-term drought in spring was delayed but WUE was decreased. Autumn-drought had no effect on the proportion of grasses, but reduced legumes and resulted in an increase in other species. Spring/summer-drought had no effect on legumes but, as the onset of drought was delayed, grasses decreased and other species increased in composition. Autumn-drought reduced canopy coverage from 34.7% to 23.8% but spring drought had a negligible effect. Results indicated that autumn precipitation was crucial for productivity of these high elevation rangelands. DOI:10.2458/azu_jrm_v54i5_koc

Semi-volatile organic compounds in the campaspe river system (Victoria, Australia)

The levels of semi-volatile organic compounds (SVOCs) in the Campaspe River system, North Central Victoria, Australia, were monitored from January to September 1995, and the environmental trends and sources of these compounds were determined. The land use within particular catchments dictated the complexity of the SVOCs in run-off water. Run-off from native forest contained the greatest number of SVOCs. Soil and ground litter were shown to contain the greatest complexity of SVOCs, mostly terpenes. However, only a small proportion were leached by run-off with the remainder being tightly bound to the soil or volatilizing to the atmosphere. Under the prevailing drought of early 1995, the rivers contained no detectable SVOCs until the first catchment run-off after significant rainfall in May. The maximum complexity and concentration of the SVOCs coincided with extensive run-off after heavy rainfall in June, effecting a surge of SVOCs with the flood peak. Fatty acids, their amides and hydrocarbons made up the majority of the compounds identified and were in the 1-39μg/l concentration range. The levels then diminished as the catchment was flushed by continual run-off. These results support Lake's 1967 hypothesis that natural floodwaters contain a signature of SVOCs entering from the catchment. The downstream passage of these compounds was obstructed by a man–made storage, Lake Eppalock, with only low concentrations of SVOCs (1–3μg/l) in the outflow, displaying no correlation to run-off.

Autumn and spring drought periods affect vegetation on high elevation rangelands of Turkey

The amount and temporal distribution of precipitation received is of critical importance for regrowth and plant production on rangelands. The effects of drought in the autumn, and spring/summer, as they affected sheep fescue (Festuca ovina L.) dominated vegetation in Eastern Anatolia, Turkey, were examined between 1996 and 1998. Artificial drought was created using polyethylene rain-out shelters. The experiment was a randomized complete block design with 3 replications with a split-plot arrangement of treatments. Main plots included 2 autumn treatments: imposed artificial autumn-drought or a 40 mm of additional water plus rain. Sub-plots contained 4 treatments: artificial drought in May, June, July, or full spring rainfall. The number of reproductive shoots, aboveground biomass production, protein content, protein yield, canopy coverage and botanical composition were determined. Reproductive shoot numbers were reduced from 617 to 31 m(-2) when plants entered winter without autumn regrowth as a result of autumn-drought. Plots subjected to drought in the autumn had aboveground biomass of 424 kg ha(-1). Protein content of forage, crude protein yield and water use efficiency (WUE) were 11.6%, 49 kg ha(-1) and 1.5, respectively. These were compared with 1,038 kg ha(-1), 9.6%, 99 kg ha(-1), and 2.4, respectively, for plots received normal autumn precipitation in addition to 40 mm of additional water. Aboveground biomass production increased as short-term drought in spring was delayed but WUE was decreased. Autumn-drought had no effect on the proportion of grasses, but reduced legumes and resulted in an increase in other species. Spring/summer-drought had no effect on legumes but, as the onset of drought was delayed, grasses decreased and other species increased in composition. Autumn-drought reduced canopy coverage from 34.7% to 23.8% but spring drought had a negligible effect. Results indicated that autumn precipitation was crucial for productivity of these high elevation rangelands.

Minimum viable population size of capercaillie Tetrao urogallus: results from a stochastic model

In order to estimate minimum area requirements for viable isolated populations of capercaillie Tetrao urogallus in Central Europe, we developed a stochastic population model. Model parameters were largely based on the results of a field study in the Bavarian Alps. Environmental fluctuations (amount of rainfall in June and July) are taken into account in the early survival of chicks. For the default parameter set, the model predicts a minimum capacity needed for viability, i.e. for the extinction risk not to exceed 1% in 100 years, of about 470 individuals. In the Bavarian Alps, this corresponds to area requirements of an isolated viable population in an order of magnitude of 250 km2. These results are, however, sensitive to small changes in model parameters such as female survival, clutch survival and chick survival. We conclude that minimum viable population size and minimum area requirements may vary considerably across the range of the capercaillie. Therefore, we plan to apply our model to different parameter sets from different regions in order to explore the range of conditions under which capercaillie populations may be viable.