Important colonies of seabirds occur on all eight islands comprising the Line group of the Republic of Kiribati, the former Gilbert Islands. The greatest density and diversity is reached on Christmas Island, the principal island of the group, with 18 regularly nesting species. Climatic factors and the extent of human activities in the past, however, have led to widely differing conditions prevailing on the different islands. Christmas (which came to prominence as a post-war atomic testing-base), Fanning, and Washington, Islands have permanent settlements; the five southern Line Islands are totally uninhabited.

Wildlife generally is threatened by introduced animals, especially cats, and additionally on inhabited islands by environmental changes and the direct impact of human disturbance. A Wildlife Conservation Unit, set up in 1977, administers five reserves on Christmas Island and is responsible for the islands of Malden, Starbuck, and Vostok, which are wildlife sanctuaries. Wildlife laws give protection to the Green Turtle and to 31 resident and regularly-occurring migratory species of birds. Naturalist-orientated tours to the Line Islands constitute a key development project which provides some optimism for the future.

The wastewater of Firdaus Tanneries, Muridke, Pakistan, was very highly saline and very highly sodic (water-quality class: C4-S4). It was being used for irrigating fields near the Tanneries but there was a piece of wasteland which, because of its elevation, could not receive this water. The vegetation of this wasteland and that of the irrigated field was studied.

The effects of wastewater application on characteristics of the soil were studied in the irrigation field and, for comparison, also in the wasteland soil. The soil samples were taken from the surface and from 5, 10, and 20 cm depths. Moisture content, water-stable aggregates, water-holding and cation-exchange capacities, amounts of organic matter, and exchangeable sodium, were greater in the irrigated field as compared with wasteland soil at each corresponding soil-depth. Electrical conductivity, pH, and the amounts of calcium, magnesium, soluble sodium, chlorides, sulphates, and the values of Sodium Adsorption Ratio and Exchangeable Sodium Percentage, were significantly higher in wasteland as compared with those in the irrigated field at each corresponding soil-depth. These values tended to decrease from the surface to 20 cm soil depth in each site.

Since 1970 a large number of environmental problems have been identified as resulting from the long-term effects of human impacts. Consideration of human activity within the environment as three orders of impact, provides a basic framework for the appreciation and evaluation of long-term problems. Consequent upon dam construction, major changes of flood magnitude and frequency and of the quantity and calibre of sediment loads (first-order impacts), will induce the readjustment of channel morphology and ecology (second-order impacts). However, the macrophytic and macro-invertebrate population, for example, are also adjusted to channel morphology—particularly channel shape and substrate composition—so that further readjustments of the macrophyte and macro-invertebrate populations may be effected by changes of channel form (third-order impacts).