You have heard many eloquent arguments in favour of disarmament, but the deliberations of this Assembly have served to show the watching world that in 1982 we are still where we were in 1978—facing the same stark choice of survival or annihilation.

Modern weapons have the deadly capacity not merely to wipe out cities, industries, and even entire populations, but also to destroy the life-giving systems on which we all depend. I am convinced that the need to preserve our shared environment provides the most persuasive argument for nations to stop this dangerously escalating spiral of the arms race.

The dynamics of desert ecosystems control levels of resources that are essential to the survival of desert biotas. Because precipitation is both low and relatively unpredictable in arid regions, the climates, topographies, and soils, of these areas present formidable constraints to resource availability in space and time. And for the same reason, the processes of production, consumption, decomposition, and nutrient-cycling in deserts are also highly irregular and difficult to predict with accuracy. For example, global models relating actual evapotranspiration to primary production and decomposition apply poorly in arid regions.

Surprisingly great amounts of carbon are stored in desert soils, particularly in caliche deposits which represent a major ‘sink’ of carbon from the atmosphere. In Arizona desert soils, inorganic carbon exceeds organic carbon by a factor of > 10. Direct use of organic carbon is made principally by organisms that break down desert litter and simultaneously cause relatively high rates of nitrogen mineralization. While nitrogen is traditionally considered deficient in arid environments, its flux is considerable because of high rates of gain by fixation and loss by denitrification and volatilization. Nitrogen accumulates in ‘islands of fertility’ beneath desert shrubs where it becomes relatively available because of (i) its high concentration in plant litter, and (ii) reduced activity of any aromatic modifiers that retard decomposition.

It is misleading in deserts to relate nutrient availability to yearly averages, as nutrients may become highly available following pulses of ‘effective’ precipitation. Moreover, mineralization and subsequent availability to plants of phosphorous, the ‘master element’ in nutrient cycling, are moderately independent of nitrogen mineralization and can proceed rapidly. Clearly, the case for nutrient deficiency in deserts may be overstated.

Consumption of primary production has varying effects on rates of resource availability in desert ecosystems. Generally weak regulation of primary production is predicted for consumers of green vegetation, except occasionally during early drought. Carnivores should exert variable controls over their prey, while pollinators, seed-eaters, and detritivores—most of which are strongly soil-associated—should have the greatest impacts on primary production and nutrient cycling.

Conservation policies adopted in the Provinces of Tirol (Austria), Salzburg (Austria), Bavaria (West Germany), and Südtirol–Alto Adige (Italy), reflect the specific constitutional settings, management fields, and regional planning strategies, of these four regions in the eastern European Alps. Despite differences in historical–political heritage, their conservation programmes exhibit a number of similarities:

1. Early conservation efforts by local communities were justified on the basis of perceived economic benefits, while those of organized conservation groups were directed towards establishing reserves with the objective of strict preservation.

2. Government involvement in conservation increased in the 1970s, when comprehensive legislation covering Nature protection and regional planning was enacted by provincial authorithies.

3. Much of the land in projected and existing parks or reserves remains in private ownership, and long-held traditional land-use rights are upheld.

4. Reserves are established under individual legal ordinances which specify prohibited practices, allowable uses, and permit approval procedures. A land-use zoning approach is used only in the management of National Parks.

5. Provincial legislation requires the integration of Nature protection into regional planning policies and programmes (e.g. the Bavarian Recreational Landscape Plan). Efforts to integrate government programmes on an international level have been limited to discussion and consultation.

The controversy surrounding the proposed Hohe Tauern National Park (Austria) illustrates that, within a setting of long-established vested interests, it is difficult to reach agreement between provincial governments (with their power-utility corporations), local communities (with their economic self-interest), and environmental groups (with their often strict preservation philosophy).

The effects of controlled motorcycle traffic on a Mojave Desert soil in California were studied in order to describe soil compaction quantitatively. Four experimental trails, representing 1, 10, 100, and 200, passes each with an off-road motorcycle were established in a loamy sand at 6.2% by weight moisture content. Penetration resistance, density, infiltration rate, and response to rainfall, were measured for the undisturbed soil and for the experimental trails immediately after the conclusion of the impact, and soil cores were measured in the laboratory to determine pore-size distributions. The soil density was remeasured again one year after the impact, to determine the amount of recovery.

Immediately after motorcycle use, the average density of the soil in the 0 to 60 mm depth increased from an average of 1.53 metric tons/cubic metre in the undisturbed soil to 1.77 t/m3 in the 200 pass trail, and the average density in all the trails could be expressed empirically as a logarithmic function of the number of motorcycle passes. The soil penetration resistance profile for the 200-passes-trail showed that the maximum compaction occurred between 30 and 60 mm depth, and that changes in penetration resistance could be measured to a depth of 0.21 to 0.25 m. The infiltration rate after 2 hours decreased from an average of 98 mm/hr in the undisturbed soil to 29 mm/hr in the 200 pass trail.

The undisturbed soil infiltrated artificial rainfall up to an intensity of 46 mm/hr before surface ponding occurred in the 100- and 200-passes-trails at intensities greater than 25 mm/hr. Decreases in the soil-pore volume were greatest in pores with effective radii greater than 150 μm, with incremental decreases occurring in pores with radii between 150 and 4.5 μm; the total volumes of smaller pores were similar in the compacted and undisturbed soils. One year after the impact, the density of the soil at a depth of 0–30 mm had decreased significantly in the 10-, 100-, and 200-passes-trails but the densities at 30–60 mm depth remained unchanged.

The Author's method of evaluating a natural park system is based on that devised and used some 10 years ago by the National Park Service of the USA (i.e. exactly a century after the institution of the first national park of that country and of the world, Yellowstone). In the American evaluation of 1972, serious gaps and inadequacies were identified in the national park system of the USA, which until then did not grow as a ‘system’ but rather as an aggregation. However, that system and its features are not described or commented on, but only the method itself is described.

Then the method is applied to a much smaller (Italian) region—Piedmont—in which the ‘natural parks and reserves system’ has only recently been planned and is beginning to be set up—generally with good individual choices, but apparently without any other sound criterion. The Author finds that the method is still meaningful and useful and, after a brief description of Piedmont in so far as the method requires it, he expounds his main conclusions about the inadequacies of the system and the possible remedies.

Finally, the method is briefly examined in a general way and some remarks are made about it, in order to point out its main merits, which are its synthesizing capacity and its simplicity: so appealing are they, that it is felt necessary to give some warnings about its limitations, which include lack of consideration of sizes of areas, their number, and their distribution.

The utilization of tussock grasslands in the semi-arid and sub-humid tussock grasslands of Central Otago, South Island, New Zealand, by European sheep farmers, began during the 1850s. Many of the sheep farmers and their hired shepherds migrated from the Scottish Highlands, and brought with them the management practices with which they were familiar. The extensive sheep farms or ‘runs’ were rented on government-owned land, and the graziers did not enjoy long-term security of tenure; nor did they receive compensation for any improvements which they might have undertaken during their occupancy.

The combination of frequent burning of the vegetation and overgrazing soon resulted in a perceptible decrease in vegetation cover, such that land deterioration accelerated in the 1870s and 1880s when a rabbit pest irrupted. No effective action was taken to deal with the problem of land deterioration, and by the early part of the twentieth century parts of Central Otago were described as man-made desert. The tussock grassland had given way to almost bare soil interspersed with patches of Scabweed (Raoulia lutescens), and accelerated soil erosion resulted in slope-wash and gullying. Remedial action was delayed by the outbreak of the First World War, but a major Commission of Inquiry at the end of the war concluded that unsuitable forms of land tenure had contributed significantly to the desertification and land deterioration.

Eventually, changes in land tenure were introduced, providing for security of tenure, entitlement to compensation for land improvements, and controls on husbandry and stocking levels.

Implementation of a conservation policy of preserving representative samples of all the natural ecosystems in the country has led to the establishment, from 1974, of two high-foresi national parks, namely the Bia and the Nini-Suhien, of an area now totalling 252 square kilometres or 0.3% of the original high-forests of Ghana. Continuing pressures to permit logging and other forms of exploitation for short-term cash benefits suggest that, unlike the national parks in the savanna zone, the need for high-forest national parks is yet to be fully appreciated.

High-forest national parks are vital as:

– A reference-base for scientific studies and for comparison with forests that have been modified through logging, sylviculture, and farming; they may thus provide data for decisions on the most desirable future management of high-forest areas;

– A genetic bank for the most important timber trees and for rare and endangered species and other taxa of fauna and flora;

– A focal point for the breeding and spreading of wild animals which are widely exploited for meat throughout Ghana;

– As a tourist and recreational asset; the high-forest itself is the chief tourist resource within the high-forest zone, providing a unique atmosphere for relaxation and outdoor recreation; and

– As an educational, cultural, ecological, and scientific, heritage of the greatest importance.

Internally, therefore, the policy of creating and maintaining high-forest national parks needs to be strengthened against political and economic pressures, with pursuit of a vigorous effort at educating decision-makers and the general public to an understanding of the many intangible values of natural forests. Externally, a common habitat-conservation policy for the West African subregion is urged—not only to prevent smuggling of protected, rare, and endangered, species across national borders, but also because the environmental consequences of the abuse of Nature recognize no such national frontiers.