Series Of Dry Years Research Articles

N equals two (times five). Exploring the effects of horse rewilding on five congeneric adult butterflies

Rewilding incomplete ecosystems by using ungulate megaherbivores represents a significant potential for sustainable management of habitats of declining species. Two xeric grasslands patches in the Podyjí National Park, Czech Republic, were rewilded by a feral horse breed, the Exmoor pony, in 2018. Before this in 2017, demography, mobility, and adult habitat use of five congeneric Melitaea butterflies co-occurring at the grasslands were investigated (Vodickova et al., J. Nature Conserv. 2019). In 2021, four seasons after the rewilding, we replicated the survey to assess the effects of the horse on the butterflies. Here, we compare the results of the two surveys and investigate changes in spatial patterns of adult distribution using Ripley’s K-functions.Total numbers of captures, and estimated population sizes, were consistently lower in 2021, with the largest drop for spring-flying M. cinxia. We cannot discern whether this was due to the cold 2021 spring, or due to reduction of grasses by the horse, possibly contributing to desiccation of M. cinxia host plants. Demographic parameters such as residency/longevity and capture probability changed only little. Mobility ranking among species remained identical, but within species, some mobility characteristics changed among years. Among early summer species, M. britomartis, second most abundant in 2017, switched to the first position with M. aurelia, and these two species displayed the most notable shift in adult habitat use between the two seasons. Short thorny shrubs avoided by the horse protect M. britomartis host plants; this threatened butterfly thus did not suffer from horse presence. M. athalia, a species of woodland edges, profited from decay of conifers caused by a series of dry years; and M. didyma, forming multiple generations, from increase of its host plant. Contrary to expectations, spatial distribution of most butterflies became more aggregated within rewilded pastures, probably due to regularities in home ranges use by the horses, which restructured the vegetation in a zonal, rather than patchy, way. A considerably larger areas should be rewilded by the herbivores to fully achieve the desired beneficial effects.

The benefits of publishing in society‐owned scientific journals

The benefits of publishing in society‐owned scientific journals

Simulating Variations in Reservoir Eutrophication Level by Reproducing Biogeochemical Cycles

The prediction of qualitative effects of long-term succession of aquatic organism communities with possible responses of the ecosystem to disturbances of the natural homeostasis becomes possible with the structure of the ecosystem taken into account. Among the possible lines of its development, analyzed is the one that maximizes a thermodynamic characteristic—exergy, which reflects how far the ecosystem stands from the state of “dead” matter. The results of calculations by a modified model of biogeochemical cycles in a series of dry years are in agreement with the expert estimates for the development of eutrophication process in the Novosibirsk reservoir in the recent years. A nonmodified model fails to provide such agreement.

Biomass removal by clipping and raking vs burning for the restoration of abandoned Stipa‐dominated European steppe‐like grassland

AbstractQuestionDo restoration measures involving yearly biomass removal over 9 yr have a beneficial effect on the structure and composition of long‐term abandoned European steppe‐like grassland? What is the effect of a single accidental fire event on this grassland community?LocationContinental dry steppe‐like grassland, Suatu and Puini, Transylvania, Romania.MethodsIn two long‐term abandoned grassland sites, we experimentally carried out annual biomass removal by clipping and raking, and by raking alone over a period of 9 yr. We analysed the effect of the two planned treatments in both sites and that of an accidental fire in one of the sites on the structure and composition of vegetation. We applied a predominantly functional trait‐based analysis, but the dominant species Stipa pulcherrima and Carex humilis were treated separately.ResultsAnnual biomass removal applied for 9 yr at one site favoured sub‐dominant grasses and short‐lived forbs over long‐lived forbs and the two dominant species, and generated a successional shift to more open grassland. The clipping and raking treatment promoted plot‐scale species richness when the grassland species pool was large enough. The number and abundance of Red‐Listed species were not influenced by our treatments. The single accidental fire event at one of the sites negatively affected the two dominant species and promoted one of the sub‐dominant grasses. In addition, burning in combination with abandonment and presence of stoloniferous grass species benefiting from fire decreased species richness. Variation in weather conditions, in particular the series of dry years during our experiment, caused significant changes in vegetation cover and the quantity of litter, and decreased the abundance of S. pulcherrima in both sites and that of long‐lived forbs in one site.ConclusionsAccording to our results, biomass removal had a beneficial effect on vegetation structure and composition in long‐term abandoned steppe‐like grassland. Until further experimental data on the effect of burning on temperate dry grassland are available, traditional management practices should be favoured over alternative methods.

Bodenversauerung in den Flächen des Interkantonalen Walddauerbeobachtungsprogramms

Soil acidification in permanent observation plots Soil acidification is followed in Swiss forest observation plots differing in soil chemistry. Soil solution samples from suction cups show clearly increasing soil acidification between 1998 and 2011, although the rate has declined in many cases during the last five years. The most rapid decline is currently observed in plots with medium to high base saturation. Nitrogen addition experiments and time series after thinning out forests confirm the important role of nitrogen input and nitrate leaching for the acidification process. It is suggested that the slowdown of acidification since 2003 has several reasons: reaching of the aluminium buffer range in the very acidic plots, decreased nitrate leaching in a series of dry years, reduction of acid deposition.

The influence of agronomic advice upon soil water thresholds used for planting decisions in Southern Queensland’s grains region

At least two decades of sustained research, development and extension (RD&E) effort was undertaken in Southern Queensland’s broad acre cropping zone regarding the role of stored soil water in crop performance. Grain industry concern that the resulting insights into stored soil water were not being integrated into the planting decisions of grain producers was raised when a series of dry years culminated in widespread wheat crop failure across Southern Queensland’s Darling Downs in the winter of 2007. This paper reports on a resulting qualitative investigation into the use of stored soil water research in planting decisions in this cropping region of Australia. A dual sample of grain producer and agronomic RD&E advisors were interviewed in-depth in order to establish what planting strategies were used by grain producers, explore the relationship between these strategies and agronomic advice, as well as the relationship between grain grower’s planting decisions and their short and long term economic objectives. We found that all of the interviewees understood the role of stored soil water in crop performance. However, this understanding supported three distinct planting decision strategies: plant only when a stored soil water threshold has been reached; take the opportunity to plant at least some crop each season; and plant at the appropriate time to maximise crop yield and consider stored soil water a bonus. These planting strategies were perceived by the interviewees to be aligned to agronomic advice differentiated by its commercial terms. Private agronomists, hired via an annual retainer, tended to be associated with the first planting strategy while retail agronomists, hired through the purchase of chemicals, were perceived as associated with the second strategy. These results indicate that an industry wide comparison of planting strategies in terms of yield outcomes and economic performance over multiple years is warranted in order to facilitate industry wide discussion of the trade-offs between long term enterprise profitability and short term economic pressures.

Les conditions climatiques de la torrentialité au cours du Petit Age Glaciaire en Provence

The aim of this article is to characterize the climatic conditions of torrentiality in Provence during the Little Ice Age. The study is based on chronicles of floods and overflowings of the sub-alpine torrents (the Ubaye valley in particular) and on instrumental measures of rainfalls in Marseilles. Several periods marked by frequent floods in the Durancian hydrosystem follow periods of relative tranquillity. This study shows that streams, according to their rank, do not have the same regimes of floods, so testifying of different meteorological forcing, that the frequent occurrence of floods during the Little Ice Age is not linked to a global increase of pluviometrical but to an increased variability of interannual rains, periods of more frequent floods corresponding to series of rainy years (1750-1800, 1830-1860) and periods of rarefaction of floods corresponding to series of dry years (1800-1830). The crossing of these data with other paleoclimatic indicators such as the series of growth rings of mountain larches offers perspectives to characterize the regional nuances of the Provençal climate on the historical time scale.

Groundwater resources in the Kouris catchment (Cyprus): data analysis and numerical modelling

The Kouris catchment in Cyprus is currently experiencing a scarcity of water resources due to the semi-arid climate across the southern part of the region, a series of dry years, and recent surface/subsurface water over-extraction. The catchment consists of the upper part of an ophiolitic complex in the North, which is considered a very significant aquifer for Cyprus, and an overlying sedimentary complex in the South, which has low water storage capacity. Water balance calculations are conducted using a steady state groundwater model. The recharge rate was calculated to be between 12 and 16% of the total annual rainfall. This agrees, with an estimate based on the mass balance of chloride. When the rate of extraction was increased to a value close to the present water demand, river baseflow was reduced from 25 to 18 Mm3 per year. Other negative impacts were extreme drawdowns and drying up of springs.

Groundwater resources in the Kouris catchment (Cyprus): data analysis and numerical modelling

The Kouris catchment in Cyprus is currently experiencing a scarcity of water resources due to the semi-arid climate across the southern part of the region, a series of dry years, and recent surface/subsurface water over-extraction. The catchment consists of the upper part of an ophiolitic complex in the North, which is considered a very significant aquifer for Cyprus, and an overlying sedimentary complex in the South, which has low water storage capacity. Water balance calculations are conducted using a steady state groundwater model. The recharge rate was calculated to be between 12 and 16% of the total annual rainfall. This agrees, with an estimate based on the mass balance of chloride. When the rate of extraction was increased to a value close to the present water demand, river baseflow was reduced from 25 to 18 Mm 3 per year. Other negative impacts were extreme drawdowns and drying up of springs.

Burning of Northern Mixed Prairie during Drought

Burning of Northern Mixed Prairie during Drought

THE DRYING OUT OF THE ARAL SEA AND ITS CONSEQUENCES

The author examines the problem of the present state of the environment in the desert irrigation districts of southern Kazakhstan and Central Asia. A drop of the level of the Aral Sea and the formation of new land on the exposed seabed, the desiccation and desertification of the Amudarya and Syrdarya deltas caused by an intensification of agriculture have been proceeding against the background of a series of dry years. Irreversible environmental changes are having a negative impact on the socioeconomic conditions of the Aral region. The author, basing himself on the results of scientific investigations related to the Aral Sea problem, proposes a number of measures designed to moderate this negative impact.

Experience of operating the Kairakkum Hydroelectric Station in Tadzhikistan in dry years

1. The experience with operating the units of the Kairakkum hydrostation in dry 1974 at a head considerably below that allowed by the manufacturer showed that they have a certain margin of safety, which made it possible to operate the units under such conditions during a series of dry years. 2. The possibility of protracted trouble-free operation of the Kairakkum hydrostation units at low heads permitted the decision to dispense with their labor-intensive dismantling, which was done in 1974, in view of the absence of appropriate operating experience, as a result of which during the next three dry years at least 900,000 rubles were saved. 3. The experience of operating the Kairakkum hydrostation showed that the delivery of a 500–600 m3/sec discharge required for irrigation is feasible through turbines operating at low heads with a reservoir water level far below the dead storage level. 4. In the structures of hydrostations operating on irrigation schedules it is desirable to have bottom outlets which permit the release of water under conditions of deep drawdown of the reservoir.

Land for the Fellahin, II

The great desert of Syria is not an absolute void. The steppes on its flanks enjoy a little rainfall, basins of interior drainage accumulate in their lowest parts enough moisture to produce a fast-growing grain or fodder crop, and the dry beds of wadis (arroyos) support a certain minimum of pasture. The subsurface water below them can often be reached by dug wells which the Bedouin uses as a basis of operations. But there is no fixed boundary line between the Desert and the Sown throughout the great belt that extends from the Red Sea to the Persian Gulf. After a series of dry years the desert is wont to reclaim its own, spilling its people, the nomads, over into the area occupied by sedentary agriculturalists. Bedouins are a prolific people; the desire for the continuity of the family is very strong. Further, to keep up the fighting strength of the tribe is a sine qua non if it is to continue to survive. To have children is the summum bonum in the eyes of man and of Allah. Living conditions on the desert are harsh, and Bedouin children are born under conditions which would seem to most Westerners little short of infanticide. Midwifery is of the most primitive order, and the infants who survive must be fit and hardy indeed. The miserable goat-hair tent, some ten feet long, seven feet wide and five feet high, is neither wind-proof, sand-proof, nor water-proof; yet it is the only shelter against the sun and sandstorms of summer and the cold, howling winds of winter. Sheep, goats and members of the family live together in the most intimate and friendly symbiosis, sharing their warmth, their filth and their fleas. Under such conditions children are born, and they pass their months of immobility on the floor of the tent, covered with dirty, vermin-infested rags, while their mothers milk the sheep, make the bread, carry water from the spring, and perform their other household tasks. But living conditions are basically wholesome, much more so than in most city slums. The nomad does not stay long enough in one place for slops and garbage to accumulate. The desert air is singularly free from noxious bacteria, and the continuous sunshine is most salubrious. Hence, in spite of a high rate of infant mortality, many children survive the rigors of desert

The Rehabilitation of the Prairie Wheat Economy

The prairies and the country north of them are in truth a diversified country about which accurate generalizations are not easily made. A series of good crop years tempts both settlers and writers to predict cultivation in the most distant situations. A series of dry years invites equally extreme predictions of restriction of settlement…. In Canada … it is refinement of observation on critical elements and seasons of precipitation that we need rather than figures of annual rainfall, which are often almost meaningless. An old plains farmer once remarked to me “Annual rainfall? We have no such thing as an annual rainfall here! Once in a long while it rains.”—[Isaiah Bowman]Standards of living in the prairie wheat economy have been depressed by overhead costs, recurring cycles of drought, specialization in wheat, and dependence on prices determined in world markets. The record of the last eight or nine years has brought suggestions that the greater part of the area should be abandoned or allowed to revert to range use, although a more general assumption has been that drought would give way to years of greater precipitation and that wheat prices would show a measure of recovery. Drought and depression have indicated that throughout the region emphasis has shifted from problems of exploitation to problems of conservation and that, accordingly, an attempt must be made to re-establish the economy on a basis which will reduce the waste of human and economic resources in the future. Individual initiative and local group action will undoubtedly continue to play an important part in the adaptation of agricultural techniques to climatic and soil conditions, but correction of the most glaring mistakes in settlement and land utilization policies demands careful planning and constructive action on a fairly large scale by federal and provincial governments. From the national or social point of view, more is at stake than relief budgets and rehabilitation expenditures, onerous as the financial burden of these charges may be. Successive years of extreme poverty in a depressing environment have begun to sap the morale of all but the most fortunate or the most determined members of the prairie community, and continuance or recurrence of such conditions must ultimately produce a demoralized agricultural population.

Hydrographic and Meteorological Surveys for Water Supply

The water works engineer is faced with the necessity of having an assured supply of water for the community that he serves. Some cities have at their very doors a supply whose quantity is so great that potability is the only serious question ; others must study methods to obtain volume, potability, accessibility and dependableness. Western cities to a large number have limited water supplies, the limit being usually found in the lack of dependence that can be placed upon the supply during the periods of drought. The growth of Southern California has taken place to a large extent, during a series of dry years and to obtain a knowledge of the local sources of water supply stream flow records were started about thirty-five years ago. As the surface supply became less available for expansion recourse to underground sources became necessary; conservation of supply made a knowledge of what could be expected from precipitation a prerequisite to an intelligent estimate of future supply, when coupled with an understanding of the nature and extent of the operating losses in collection and distribution. Records of precipitation at stations located at fairly regular distance intervals from Mono Lake to Los Angeles, also of temperatures, wind velocities and evaporation constitute the meteorological data regularly obtained by the Hydrographie Section of the Department of Water and Power of the City of Los Angeles. The rainfall records are the more frequent in spacing, due to the 594

Water Supply 1

ONE of the difficulties besetting the agriculturist in the vast area known as the Great Plains and constituting the central region of the United States is the irregular rainfall. The land is fertile enough, but a recurring series of dry years militates greatly against its effective development. Attempts have been made to remedy the evil by means of artificial irrigation, but so far these efforts have been sporadic and local, and, consequently, they have not produced the completely beneficial results which might be obtained if all the ground water were systematically conserved and utilised.