Avoidance of low pH and elevated Al concentrations by Brook Charr (Salvelinus fontinalis) Alevins in laboratory tests

Laboratory studies were conducted to test the ability of brook charr (Salvelinus fontinalis) alevins, the earliest free-swimming life stage of the species, to detect and avoid toxic levels of H⁺ and inorganic Al. Alevins were tested in steep gradient choice tanks using a range of H⁺ (pH 4.0 to 5.5) and Al (0 to 500 μg L^?1) concentrations in low Ca (2.0 mg L^?1) water. The young brook charr actively avoided acidic water with a pH < 5.0. Aluminum additions of 500 μg L^?l increased the avoidance response. The observed behavioral response of alevins to low pH and elevated levels of Al, may be of significant adaptive advantage in systems undergoing acidification.     

Macroinvertebrate frequency data for the RIVPACS III sites in Northern Ireland and some comparisons with equivalent data for Great Britain

1. A total of 313 macroinvertebrate taxa were recorded from the 70 running‐water sites in the R iver I nV ertebrate P rediction A nd C lassification S ystem (RIVPACS III) dataset for Northern Ireland, after the application of a standardization procedure to ensure that all samples were identified to the same taxonomic level. The listing includes a small number of oligochaetes not previously reported from Ireland. The frequency of occurrence of the 313 taxa within the Northern Ireland dataset is also presented. 2. The taxonomic composition and frequency of occurrence of taxa in the Northern Ireland dataset were then compared with the 614 site dataset for Great Britain, which included 637 taxa, and a 75 site subset within Britain at a similar latitude to Northern Ireland with 333 taxa. 3. The macroinvertebrate fauna of Northern Ireland is dominated by taxa recorded at the highest frequencies of occurrence in Britain. Some notable absences are highlighted and, in particular, a small number of lotic mayflies and stoneflies which are common in Great Britain. There is documentary evidence of the introduction by man of a number of non‐insect taxa, either deliberately or by accident. 4. A detailed knowledge of the present composition of the macroinvertebrate fauna of running‐water sites in Northern Ireland, and an active research programme on the potential for new colonists to pose a threat to native species, are important factors in the future conservation of the freshwater fauna. Copyright © 2000 John Wiley & Sons, Ltd.     

Comparative analysis of monoclonal antibodies against pestiviruses: report of an international workshop

Thirty-three pestivirus strains were grown in cell culture and characterized by immunostaining with 19 monoclonal antibodies (MAbs) raised against hog cholera virus (HCV), with 42 MAbs against bovine viral diarrhoea virus (BVDV) and with 13 MAbs against border disease virus (BDV). Seven MAbs reacted with all pestivirus strains tested, eight MAbs detected only the seven HCV strains, three detected only the 16 BVDV strains. No MAb was found that was specific for BDV. BVDV and BDV strains were broadly cross-reactive with the MAbs, indicating a close relationship between these two species, whereas HCV strains were characterized as distinct from BVDV and BDV.     

Adaptations of skeletal muscle that favour athletic ability

The preparation and use of a blowgun apparatus is described for injection of animals which cannot readily be physically restrained. The apparatus has been in use at Taronga Zoo for some months, providing a reliable and economical alternative to commercially available systems.     

Locust Plagues and the Dieldrin Controversy

Abstract

The accepted strategy for the control of locust plagues is to check an upsurge of population before swarms break out and start a widespread plague. The organisation, men and materials necessary for this work must be established before locust plagues are imminent. Primary targets for control are the hoppers. Red locust hoppers can be efficiently controlled only by vegetation baiting with dieldrin. The ULV drift-spraying method of application is particularly successful. Objections to the use of dieldrin on environmental grounds have been put forward but are without substance when the recommended method is used. A small aircraft can blanket spray 5,000 ha/h using the ultra low dosages necessary for desert locust hoppers. Three such aircraft could cope with the area of red locust hopper outbreaks although the dosage necessary for these is likely to be higher in the denser vegetation of their habitat. Field trials to establish the lowest dosage rate for red locust hoppers are urgently required.

If the facilities and resources needed to control locust plagues are not made available, it is hoped that FAO will provide expert teams to survey the economic and social effects of a locust plague, by investigation on the spot, so that responsibility can be assigned and an accurate history can be drawn up for the guidance of future governments. At the present time, governments have the choice of providing what is needed in the confident expectation of preventing plagues, or providing too little or nothing which will, sooner or later, inevitably lay a plague on their doorsteps.     

Quantifying patch distribution at multiple spatial scales: Applications to wildlife-habitat models

Multiscale analyses are widely employed for wildlife-habitat studies. In most cases, however, each scale is considered discrete and little emphasis is placed on incorporating or measuring the responses of wildlife to resources across multiple scales. We modeled the responses of three Arctic wildlife species to vegetative resources distributed at two spatial scales: patches and collections of patches aggregated across a regional area. We defined a patch as a single or homogeneous collection of pixels representing 1 of 10 unique vegetation types. We employed a spatial pattern technique, three-term local quadrat variance, to quantify the distribution of patches at a larger regional scale. We used the distance at which the variance for each of 10 vegetation types peaked to define a moving window for calculating the density of patches. When measures of vegetation patch and density were applied to resource selection functions, the most parsimonious models for wolves and grizzly bears included covariates recorded at both scales. Seasonal resource selection by caribou was best described using a model consisting of only regional scale covariates. Our results suggest that for some species and environments simple patch-scale models may not capture the full range of spatial variation in resources to which wildlife may respond. For mobile animals that range across heterogeneous areas we recommend selection models that integrate resources occurring at a number of spatial scales. Patch density is a simple technique for representing such higher-order spatial patterns.