The degradation of the algerian environment through economic and social ‘development’ in the 1980s

Concern for the better management of environmental resources grew during the 1980s. While this concern encompassed the misuse of the Third World's resources, those nations' governments and their peoples showed less awareness of the environmental damage being done in their quest for development. Environmental degradation has reached serious proportions in Algeria where oil wealth has masked failings of agricultural production and, together with industrialization, has provided a ‘veneer’ of economic development. The vulnerability of Algeria's natural environment and the fragility of its ecosystems have been stressed by Cǒte (1983). Once cleared, Algeria's woodlands and forests are slow to re-establish and surface deposits are easily erodable. Soils were largely formed under past climatic conditions, and so cannot be restored naturally by present pedogenetic processes. Such an environment is difficult and delicate to exploit to any high degree of agricultural intensification and is under increasing demographic pressure. Culturally and organizationally the agricultural system is far from ideal if agriculture is to be sustained. Often in Algeria the highest rainfall falls on the steeper slopes while the gentler slopes receive insufficient for agriculture. Only 500 000 hectares out of Northern Algeria's 38–40 million hectares receive more than 600 mm of rainfall and have slopes of less than three per cent (Cǒte, 1983). As much as 20 million hectares of Northern Algeria were identified by Dregne (1983) as … ‘vulnerable to desertification’ with large areas falling into his ‘severe’ risk category. This study seeks to demonstrate the dimensions of environmental degradation through observations and the monitoring (during the 1980s) of Algeria's media: largely newspaper and television reports. Particular emphasis is placed on the growing environmental ‘crisis’ since 1988. It should be stressed that the Algerian Government uses a controlled media to disseminate official information. Misuse and overuse of environmental resources have combined with inadequate government economic policies and a neglect of ecological issues to cause the ‘crisis’.     

Detectability of step trends in the rate of atmospheric sulphate deposition

Step trend analyses are performed on acid deposition rates using a combination of monitored sulphate deposition data and a long-range transport of acid precipitation (LRTAP) model. The step trend analyses consider Sudbury's emissions and eastern North America's emissions to explore strategies for reducing SO₂ emissions such that a decrease in sulphate deposition is detected in a specified time period. Results indicate Sudbury's emissions could be reduced with significant detectable reductions in sulphate deposition occurring at the Muskoka region. Significant detectable reductions do not occur elsewhere due to the variability of monitoring data ‘masking’ the small change in sulphate depositions associated with abatement. Reductions in eastern North America's emissions would result in widespread evidence of significant detectable reductions.     

Nutrient Solution and Solution pH Influences on Onion Growth and Mineral Content

The effects of hydroponic nutrient solution composition and pH on growth and mineral content of green onions was evaluated. Three onion varieties [Allium cepa L. (‘Deep Purple’ and ‘Purplette’) and A. fistulosum L. (‘Kinka’)] were propagated in three nutrient solutions (Peter's Hydro-Sol, modified Hoagland's, and half-strength modified Hoagland's) at two pH levels (5.8 and 6.5) in a three-by-two factorial design applied in a randomized block with three replications. Seeds were germinated in Cropking's Oasis Horticubes under greenhouse conditions and irrigated with tap water. Once the seedlings reached the flag stage, the plants were placed into hydroponic units within the greenhouse and grown under ambient conditions. Plants were harvested 30 d after transplanting to the hydroponic units. The results indicated nutrient solution, pH, and variety significantly affected several plant physiological variables. Total biomass and edible biomass production was as high for plants grown in half-strength Hoagland's nutrient solution as for those grown in the other solutions. Total biomass was greatest for plants grown at a solution pH of 6.5. ‘Deep Purple’ produced a significantly greater overall total biomass than did ‘Purplette’ or ‘Kinka.’ Hydro-Sol tended to produce onions with highest mineral content. Due to the fact that biomass production was as great in the half-strength Hoagland's as in the more concentrated solution and that a pH of 6.5 produced greater total biomass, the half-strength Hoagland's solution at pH 6.5 was the preferred nutrient solution evaluated in this research. Selection of an appropriate nutrient solution must consider both edible biomass production and mineral content. In the research reported here, the solution that produced the greatest biomass did not produce plant material with the highest mineral content.     

Modelling the effects of bioturbation on the re-distribution of 137Cs in an undisturbed grassland soil

Under favourable conditions, soil ingestion by earthworm populations can be equivalent to approximately 5–10% of the topsoil mass per year. This suggests that for contaminants that are strongly bound to soil, earthworm ‘bioturbation’ may be a more important transport mechanism than water‐borne advection dispersion. It is therefore quite surprising that few modelling studies to date have explicitly considered the effects of biological processes on contaminant transport in soil. In this study, we present a general model that incorporates the effects of both ‘local’ and ‘non‐local’ biological mixing into the framework of the standard physical (advective‐dispersive) transport model. The model is tested against measurements of the redistribution of caesium‐137 (¹³⁷Cs) derived from the Chernobyl accident, in a grassland soil during 21 years after fallout. Three model parameters related to biological transport were calibrated within ranges defined by measured data and literature information on earthworm biomasses and feeding rates. Other parameters such as decay half‐life and sorption constant were set to known or measured values. A physical advective‐dispersive transport model based on measured sorption strongly underestimated the downward displacement of ¹³⁷Cs. A dye‐tracing experiment suggested the occurrence of physical non‐equilibrium transport in soil macropores, but this was inadequate to explain the extent of the deep penetration of ¹³⁷Cs observed at the site. A simple bio‐diffusion model representing ‘local’ mixing worked reasonably well, but failed to reproduce the deep penetration of Cs as well as a dilution observed close to the soil surface. A comprehensive model including physical advective‐dispersive transport, and both ‘local’ and ‘non‐local’ mixing caused by the activities of both endogeic and anecic earthworms, gave an excellent match to the measured depth profiles of ¹³⁷Cs, with predictions mostly lying within confidence intervals for the means of measured data and model efficiencies exceeding 0.9 on all sampling occasions but the first.     

Compost Practices for Improving Soil Properties and Turfgrass Establishment and Quality on a Disturbed Urban Soil

Urban land disturbance degrades physical, chemical, and biological soil properties by removing topsoil and compacting the remaining subsoil. Such practices create a soil environment that is unfavorable for vegetation establishment. A 3-year field study was conducted to compare the effects of various one-time compost application treatments on soil properties and re-vegetation of a disturbed soil. A disturbed urban soil received the following treatments: (1) inorganic fertilizer; (2) 2.5-cm-depth surface-applied compost; (3) 2.5-cm-depth incorporated compost; (4) 5.0-cm-depth incorporated compost; (5) inorganic fertilizer plus 0.6-cm compost blanket; and (6) inorganic fertilizer plus straw mat cover. The plots were seeded with a mixture of tall fescue Festuca arundinacea Shreb.: ‘Magellan,’ ‘Coronado Gold,’ ‘Regiment,’ and ‘Tomcat,’ perennial ryegrass Lolium perenne L. ‘Linn’, and Kentucky bluegrass Poa pratenis L. ‘Baron.’ Soil chemical and physical attributes and plant growth and quality parameters were measured during 840 days following study establishment. Soil C, N, P, K, Ca, and Mg, and turfgrass growth and quality were increased and soil bulk density was reduced by amending with composts. Incorporation of compost into soil improved soil and plant attributes more than unincorporated surface application, but the differences diminished with time. Compost benefits increased with time. One-time applications of compost can provide immediate and long-term benefits to soil and plant attributes, but there may be no need to incorporate the compost into soil, particularly if the soil has recently been loosened by tillage.     

THE COVARIANCE OF PHOSPHATE SORPTION WITH OTHER SOIL PROPERTIES IN SOME BRITISH AND TROPICAL SOILS

Phosphate sorption capacity estimated by Piper's (1942) ‘anion exchange capacity’ and Bache and Williams's (1971) phosphate sorption index were correlated with soil pH, clay, organic matter, ‘free iron oxides’ and ‘extractable aluminium’ (McLean et al., 1958) for topsoil and subsoil samples from twenty tropical and twenty British acidic soil profiles. These two groups of soils did not differ significantly in phosphate sorption. Extractable aluminium and free iron oxide were well correlated with phosphate sorption, free iron oxide being superior to aluminium in freely drained British soils but not in poorly drained ones. Organic matter content correlated well with phosphate sorption for the poorly drained British soils, and for the tropical soils when sorption capacitywas measured using a high phosphate concentration.     

Forms and extractability of manganese in potting media

Abstract

Sequential extraction of pine bark medium alone and after amendment with either manganese sulfate (MnSO₄), composted rice hulls, or soil showed that at pH 5.5–7.0 most of the manganese (Mn) exists in a form that is extracted by acidic hydroxylamine hydrochloride, and which could therefore be in oxide or strongly‐bound forms. Acidification to pH 4.5–5.0 transferred large amounts of this ‘oxide’ Mn into ‘readily available’ and ‘weakly adsorbed’ fractions. Similar extractions of Sitka spruce bark showed that most of its Mn was extracted by weak cationic reagents ('readily available’ and ‘weakly adsorbed’ fractions). Growth of oats in pine bark, peat, and eucalypt sawdust media, with and without MnSO₄ amendment, lowered the amounts of Mn in ‘readily soluble’ and ‘weakly adsorbed’ fractions and caused some loss of ‘oxide’ Mn. Comparison of data for Mn extracted by 2 mM DTPA (1:1.5 v/v) with Mn in sequential fractions showed that DTPA dissolves some ‘oxide’ Mn. The data further suggest that up to about 36 mg/L DTPA‐extractable Mn would not be toxic to most plants growing in media of pH 6.0, but 60 mg/L DTPA‐extractable Mn may be if the medium pH falls below 5.5.     

The soil-protective role of specially-shaped plant roots

Some trees and shrubs which grow on steep slopes, abrupt banks alongside watercourses, or the sides of sunken roads, shape their secondary roots of the first order, and sometimes even the main root, in such a way as to develop in them a knee-like curvature, turning back into the more compact soil. This feature, here referred to as ‘edaphoecotropism’, is considered to be the results of a number of interacting physical of this phenomenon may be cited the response by roots to undesirable extreme topographic conditions of the site—some kind of ‘escape’ by the root into a more favourable environment—and a one-sided provocation of the root's growing portion, which produces variations in the distribution of auxin and thus the peculiar curvature of the root. This ‘edaphoecotropic’ orientation of the main root-branches in trees and shrubs is of importance in the safe anchoring of plants in the soil and, hence, increasing the stability of the earth or other slope or ‘cliff’.     

Seasonal Changes of Mineral Nutrients in Fruit and Leaves of ‘Newhall’ and ‘Skagg's Bonanza’ Navel Oranges

In southern Jiangxi province of China, ‘Newhall’(Citrus sinensis Osbeck) navel orange presented a conspicuous symptom of boron (B) deficiency in mature leaves, whereas B deficiency symptoms were not manifested on ‘Skagg's Bonanza’(C. sinensis Osbeck) navel orange. In this study, changes in concentrations of B, calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn), and zinc (Zn) were comparatively investigated in the structural parts of the fruit (rind and pulp) and leaves (old leaves from last season and spring-flush leaves from current year) of ‘Newhall’ and ‘Skagg's Bonanza’ navel orange during the growing season. Two peaks of B concentrations were observed in the rind of the two cultivars during fruitlet growth and fruit enlargement, respectively. Boron concentrations were relatively high in the rind during fruitlet growth, and then decreased in both rind and pulp, whereas, during middle and late fruit enlargement significant increases were found for B in both rind and pulp of the two cultivars. Boron concentrations in old leaves of ‘Newhall’ decreased progressively and remained relatively low, whereas that of ‘Skagg's Bonanza’ was relatively high and changed slightly as the season progresses. Both Ca and K concentrations were above the critical threshold values, while their dynamics were reverse to that of B in fruit and leaves during certain times. Old leaf Mg concentrations of samples at 140 days after full bloom from the two cultivars and spring-flush leaves from ‘Newhall’ were below the threshold limit for sufficiency. In addition, Mg in old leaves was much lower from ‘Newhall’ than from ‘Skagg's Bonanza’. Spring-flush leaf concentrations of Mn and Zn and Mn concentrations in old leaves from ‘Newhall’ were relatively lacking during middle and late season, which accelerated the occurrence of B deficiency symptoms on mature leaves of ‘Newhall.’     

Bacterial air pollution from an activated sludge tank

Concentrations of air-borne coliforms and ‘other’ bacteria (defined as total bacteria minus coliforms) were measured. downwind of a sewage treatment plant activated sludge tank. The Gaussian plume diffusion equation adequately predicts concentrations of the ‘other’ bacteria; the diffusion equation must be modified by an extinction coefficient, equivalent to a half-life of about 7.4 s, to predict coliform concentrations. Coliform concentrations downwind of this tank did not present a significant health hazard, but the method is applicable to treatment plants of higher capacity and possibly greater emissions.     

Residue management for reducing evaporation in relation to soil type and evaporativity1

Abstract. Usual residue-management options are to remove the residue, use it as mulch with or without undercutting or to incorporate it into the soil. While the role of surface mulch in evaporation has been widely studied, the information on the effect on evaporation of mulch with undercutting or residue incorporated into soil, particularly in relation to soil type and evaporativity (E_o) is lacking. We studied the effect of wheat straw used in various ways on the course of evaporation loss from soil columns with three soils at Ludhiana, India and one soil at Bushland, Texas, USA, under two E_o's Energy-limited evaporation rates under mulch (E_om) followed the soil-specific relation E_om/E_o= a e^(bRes+cEo), where Res is residue rate t/ha and a, b and c are constants; E_o, is expressed in mm/d. In an effort to model the total evaporation (CE) during the energy-limited stage ‘U’ was obtained from appropriate CE versus time curves and (CE-U) was regressed over (t - ti)^0.5 to obtain the slope ‘α’ (Ritchie 1972) for the soil-limited evaporation stage. The observed ‘U’ was independent of mulch rate and E_o but was strongly affected by soil type, Values of ‘α’ decreased with increase in mulch rate and decrease in E_o and coarseness of soil. The otherwise short lived benefit of evaporation reduction with mulch per se, which peaked after a few days was maintained when residue was mixed with soil at the stage when evaporation reduction reached a maximum; this benefit continued for several weeks. Cumulative evaporation values computed from ‘U’ and ‘α’ agreed closely with the observed values under straw mulch for loamy sand and clay loam soils and for ‘undercut’ and ‘residue mixed’ treatments on all soils regardless of E_o, and for all situations under small E_o. However, for sandy loam and silt loam soils under E_o of 10 mm/d, the modified square root of the time function of Jalota et al. (1988) gave a better fit.     

Preparations of plant origin enhance carbohydrate content in plant tissues of rooted cuttings of rambler roses: Rosa beggeriana ‘Polstjärnan’ and Rosa helenae ‘Semiplena’

During rhizogenesis, carbohydrates are an important source of energy for the plant tissues. It has been hypothesised that phenological phase of the shoot plays a major role in plant's response to rooting stimulants and affects the cuttings’ carbohydrate content. Therefore, the purpose of this study was to evaluate the impact of phenological phase of the shoots and the use of rooting stimulants of plant origin on the relationship between rooting abilities and the carbohydrate content in leaves and stems of cuttings. Single-node stem cuttings of Rosa beggeriana ‘Polstjärnan’ and Rosa helenae ‘Semiplena’ were harvested from shoots in four phenological stages: flower buds closed (P1), flowers open (P2), immediately after petal shedding (P3), and 7–14 days after petal fall (P4). The following rooting enhancers were used: 0.4% indole butyric acid (IBA) (Ukorzeniacz Aaqua); 0.2% naphthalene acetic acid (NAA) (Ukorzeniacz Baqua); Bio Rhizotonic; and Root Juice?; Bio Roots. Controls included untreated cuttings. The contents of reducing and total soluble carbohydrates in leaves and shoots were estimated before and after rooting. The rooting percentage and rooting degree were determined. A relatively high or moderate natural rooting ability without any treatment were shown by R. beggeriana ‘Polstjärnan’ in 63.8%–87.5% and by R. helenae ‘Semiplena’ in 41.3%–72.5% cuttings. IBA and NAA decreased the mean rooting percentage in ‘Polstjärnan’, but increased it for P4 cuttings in ‘Semiplena’. None of the preparations had any impact on the degree of rooting. The mean level of total soluble and reducing sugars in leaves and stems of cuttings before rooting was lower than that of after root formation. The preparations of plant origin positively affected rhizogenesis and sugar contents in plant tissues, but their effect depended on shoot's phenological phase and cultivar. Plant origin preparations may successfully replace those containing IBA or NAA.     

Agromorphological genetic diversity of Spanish traditional melons

The variability of 62 Spanish landraces (and two hybrids used as reference) was described by analysing 39 morphological traits and eight SSR makers. Results showed that 81% of the examined genetic pool belonged to the inodorus type. Spanish traditional melons presented fruits from flattened and globular shapes to elliptical. Rind colour varied from pale green, almost white and yellow to dark green and almost black. Rind texture varied from smooth to intensely wrinkled. Spanish landraces also had larger fruits (average fruit weight ~2.6 kg) and longer vegetative cycles (117 days to maturity) compared to landraces from other geographical origins. Farmers seem to have focused on selection towards large fruits, which usually requires the longest production cycles. Fruit colour, size and shape seemed to have been determinant in varietal selection. Hierarchical clustering resulted in two main groups (climacteric and non-climacteric). The largest group was composed of 60 accessions of non-climacteric types, which includes the most demanded by national markets, ‘Piel de Sapo’, which fruits were characterized by an ovate or elliptical shape, a green rind, big spots and stains distributed over the whole fruit, a rounded blossom end shape and a very pointed stem end shape. The study demonstrates that the Spanish genetic pool is much more diverse. Wide variability was found in a geographical area with vast historical importance in melon farming. These evaluations has allowed the identification of several uniform groups of non-climacteric cultivars (‘Piel de Sapo’, ‘Mochuelo’, ‘Tendral’, Yellow/White, Winter and Black groups) and a set of highly variable climacteric ones. However, many accessions with singular properties remain unclassified, demonstrating the morphological variability of the studied collection. Melons in Spain have wide variability together with a vast historical importance on farms. Some fruit types, or at least some morphological characters reflected by painters during centuries, have reached the present. The present study confirmed the need to preserve these irreplaceable genetic resources and continue their study and evaluation for valuable traits which could enhance farmer’s opportunities for entering new markets.     

A participatory evaluation of improved cowpea cultivars in the Guinea and Sudan savanna zones of north east Nigeria

A number of improved varieties have been developed by the International Institute of Tropical Agriculture (IITA), combining diverse plant type with resistance or tolerance to several diseases, insect pests, and parasitic weeds and possessing other good agronomic traits. Trials were established with farmers to evaluate several new IITA-bred cowpea varieties on-farm in a process of participatory varietal selection. Central to this has been a ‘mother-daughter’ approach with researcher-managed ‘mother’ trials and farmer-managed ‘daughter’ trials in order to combine researchers' and farmers' criteria in evaluation of new varieties. In both set of trials, new varieties IT89KD-391, IT97K-499-35, and IT89KD-288 were favoured by farmers because of their high grain and fodder yields. Farmers have also shown interest in the continuous use of a local variety Kanannado Brown. It is suitable for relay intercropping; having a creeping habit, and the ability to smother weeds. The brown seeds fetch higher market prices. The implications are that improved cowpea varieties should be suitable for relay-intercropping and controlling weeds, be brown in colour, have large grain size, be pest resistant as well as give high yields of grain and fodder. At the same time, it is important that the farmer's criteria should be considered in breeding and varietal selection programmes.     

Local perceptions and regional climate trends on the Central Plateau of Burkina Faso

Due to devastating droughts in the 1970s and 1980s, climatic and environmental change in the West African Sahel has attracted a great deal of scientific research. While many of these studies documented a long‐term trend of declining rainfall, analyses conducted in the last few years suggest that a ‘recovery’ is underway. Drawing on ethnographic interviews, focus groups, and participant observation in two Provinces of the Central Plateau of Burkina Faso, we elicited local perspectives on these rainfall trends from the people who are most directly affected, namely local farmers. Fieldwork revealed that farmers in the research sites perceive that both overall seasonal rainfall and the number of ‘big rains’ during the rainy season have decreased over the last 30 years. We then tested these perceptions against rainfall records from nearby meteorological stations and found them to be corroborated. This paper illustrates how farmers of the Central Plateau now view drought as ‘normal’, having incorporated drought‐mitigation adaptations into their agricultural systems. Our case study highlights the need for ground truthing scientific analyses and assessing livelihood implications at the local level. It also advocates for sustained institutional support for rural communities, to increase their ability to adapt to climate change. Copyright © 2008 John Wiley & Sons, Ltd.     

Amending a loamy sand with three compost types: impact on soil quality

The objective of this study was to investigate the effects of the long‐term addition of three compost types (vegetable, fruit and yard waste compost – VFYW, garden waste compost – GW and spent mushroom compost – SM) on the physical properties of a sandy soil and to quantify any such effects using indicators of soil physical quality. Soil samples were taken from a field with annual compost applications of 30 m³/ha for 10 yr and various physico‐chemical analyses were undertaken. Results show a significant increase in soil organic carbon (21%) with the VFYW and GW compost types. With SM, soil organic carbon increased by 16%. Increased soil macroporosity and water content at saturation with a corresponding decrease in bulk density were observed for all compost types. However, quantification of these improvements using existing soil physical quality indicators such as the ‘S‐index’, soil air capacity and matrix porosity gave mixed results showing that these indices perform poorly when applied to sandy soils. It is concluded that the long‐term application of compost does not significantly improve the physical properties of sandy soils, but the absence of adverse effects suggests that these soils are a viable disposal option for these composts, but new indices of quality are needed for the proper characterization of sandy soils.     

Water profiles,isohydral fronts and evaporation from a sandy loam soil dried under three levels of evaporativity

Abstract

A Typic Ustochrept sandy loam was dried under constant evaporation (Eo) of 4, 8, and 16 mm/day. The soil dried more uniformly with depth under lower than under higher Eo. Downward movement of isohydral fronts could be adequately described by equations of the type, D = a + b t^0.5 (where ‘D’ is the depth of isohydral front in cm, Y is the drying time in days and ‘a’ and ‘b’ are constants). Rates of their advance were influenced by the Eo and water content of the front. Higher Eo caused earlier deviation of the cumulative evaporation (CE) from the cumulative Eo. Equations of the type, CE = m tⁿ (where ‘t’ is the drying time in days and ‘m’ and ‘n’ are constants), gave an excellent fit for all the three Eo's. Falling‐rate stage evaporation rates were sensitive to Eo during its earlier stages.     

Manganese extracted from different chemical fractions of bulk and rhizosphere soil as affected by method of sample preparation

Abstract

Rhizosphere soils had higher amounts of ‘readily soluble’, ‘weakly adsorbed’, ‘carbonate bound’ and ‘specifically adsorbed’ Mn, but had lower amounts of ‘oxide‐Mn’, than did bulk soils. This observation was true regardless of whether the comparison was based on values within moist or air‐dried treatments. Observed trends in Mn distribution between different soil fractions were qualitatively similar regardless of method of sample preparation. However, there were substantial quantitative differences depending on the method of sample preparation. Air‐dried samples increased significantly in the ‘oxide‐Mn’ fraction and decreased in its soluble and adsorbed fractions relative to moist soil samples. There was a significant effect of method of air‐drying on the distribution of Mn in rhizosphere samples. Samples that were extracted moist at first and then air‐dried accumulated more adsorbed Mn and were depleted in ‘oxide‐Mn’ relative to samples that were air‐dried initially. There was a significant rhizosphere x air‐drying interaction. Air‐drying of some rhizosphere samples resulted in a significant underestimation of the ‘readily soluble’, ‘specifically adsorbed’, and ‘oxide‐Mn’ fractions beyond the overall effect of air‐drying. The results of this study suggested that soil samples used for Mn analyses be extracted immediately in a moist condition rather than air‐dried, particularly for analyses of rhizosphere soil samples.     

Is Direct Seeding a Biologically Viable Strategy for Restoring Forest Ecosystems? Evidences from a Meta‐analysis

Ecological restoration has become an important technique for mitigating the human impacts on natural vegetation. Planting seedlings is the most common approach to regain lost forest cover. However, these activities require a large economic investment. Direct seeding is considered a cheaper and easier alternative technique, in which tree seeds are introduced directly on the site rather than transplanting seedlings from nurseries. To evaluate the effectiveness of direct seeding, we conducted a comprehensive search of the literature using ‘restoration’, ‘direct seeding’ and ‘sowing’ as keywords, and we performed a meta‐analysis using 30 papers and 89 species. We used two different measures of restoration success: seed germination probability and success probability (the chance that a seed germinates and survives until the end of the experiment). In general, restoration attempts using direct‐seeding techniques were relatively unsuccessful. On average, seed germination and success probability were 0·239 and 0·114, respectively, and were not affected by climate, species successional group or the application of pre‐germinative treatments. Germination and success probability increased with seed size, and the use of physical protections resulted in a nearly twofold increase in germination probability, but this effect faded by the end of the experiments. Because of the low rate of seedling success, we suggest the use of direct seeding as a complementary technique to reduce restoration costs, particularly for species with large seeds and known high germination rates, but our results do not support direct seeding as a substitute for seedling planting. Copyright © 2015 John Wiley & Sons, Ltd.     

Pronghorn foraging economy and predator avoidance in a desert ecosystem: Implications for the convertion of large mammalian herbivores

‘Performance standards’ regulate land development by measuring the outcome or value of a proposed development, unlike ‘design standards’ which regulate the physical form. A recent municipal planning study in the Pittsburgh, PA, area has proposed the measurement of a development site's ecological performance in terms of its composite existing and potential productivity, maturity and uniqueness. A table was made showing estimated values of these performance measures for each of the ecological community types and ‘site index’ levels in the municipality. Equations were proposed for comparing a development site's ecological performance before and after development, as a way of testing the development's impact. The allowable extents to which the site's performance could be reduced by a development were suggested. Alternative development plans for a sample site showed that a developer can comply with the proposed standards by making construction areas as small as possible and locating them on the pre-existing community types with relatively low performance levels.