Petroleum and Individual Polycyclic Aromatic Hydrocarbons

European pseudo-steppes have suffered from extensive changes in agricultural practices during the past decades with the disappearance of field margins and fallow systems and the increase of biocide treat- ments. The negative effect on wildlife has led to the adoption by the European Union of policies more compat- ible with environmental conservation, but decisions about optimal land use are difficult to make because of lack of information. We studied habitat use by the Lesser Kestrel ( Falco naumanni ), a globally vulnerable spe- cies, in a Spanish pseudo-steppe (Los Monegros) where traditional agro-grazing systems are still being prac- ticed, and we compared the results with those of another Spanish pseudo-steppe where modern and intensive agriculture has been implemented. We focused on the use by Lesser Kestrels of habitats subject to changes pro- voked by recent agricultural policies. Habitat availability was determined in a 3-km radius around 11 colo- nies, where 23 Lesser Kestrels were radio-tracked during the chick-rearing stage. Habitat selection was deter- mined through compositional analysis. The rank of selected habitats was similar for all kestrels, considering both habitats surveyed and habitats where kestrels hunted. Kestrels selected field margins and cereal fields and rejected abandoned crops and scrubland. This selectivity seemed to be due to prey availability. In the in- tensively cultivated areas the kestrels selected similar habitats but used only small foraging patches and ob- tained smaller prey than in the traditional agro-grazing systems, probably because of the irregular distribu- tion of prey resources as a result of the intensive biocide treatments. Consequently, in intensively cultivated habitats Lesser Kestrels had larger home ranges (63.65 km 2 ) than in those with traditional systems (12.36 km 2 ). These differences are reflected in the productivity and population trends of both populations. Thus, the best strategy for conserving the Lesser Kestrel seems to be the maintainance of traditional cereal cultures with low biocide treatments and numerous field margins. Both agricultural intensification and marginal land abandonment (with subsequent scrubland invasion) have detrimental consequences for this and probably for other pseudo-steppe species. Positive management steps can be encouraged by recent agro-environmental regulations such as the 2078/92 European Union Reglament, which favors the creation of programs in which agricultural practices accord with wildlife conservation.

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Conflicts between Lesser Kestrel Conservation and European Agricultural Policies as Identified by Habitat Use Analyses

Predictive models for Lesser Kestrel (Falco naumanni) distribution, abundance and extinction in southern Spain

https://digital.csic.es/bitstream/10261/57749/1/abd.pdf

Does land irrigation actually reduce foraging habitat for breeding lesser kestrels? The role of crop types

This book is the most recently published in a series entitled ‘Adaptations of desert organisms’. Previous volumes have dealt with the ecophysiology of fauna and flora groups in arid and desert environments either generically or focusing on specific geographic localities. While many plants and animals adapt to extreme conditions by using various behavioural or physiological tactics, an alternative strategy is to move opportunistically or seasonally to find resources to survive. In this volume Richard Dean examines how birds, as part of their survival strategies, move nomadically within or between arid and semi-arid regions to find resource-rich patches. In the first chapter the main, large, arid and semi-arid areas on every continent are defined, with an overview of bird species restricted to these regions. It is interesting to note that although the review specifically excludes waterbirds in arid regions, the Grey Gull (Larus modestus) and Cream-coloured Courser and Somali Courser have been included in this list. The utilisation of man-induced habitat modification, such as roads, is observed to be a successful survival strategy for some species, whereas rainfall is the strongest factor influencing overall species richness in these regions. Chapter 2 focuses on migration and movement of desert birds with a discussion of the categories of movement in relation to the characteristics of resident, migrant and nomadic species. The author’s overall conclusion is that there is a correlation between winter temperatures and the proportions of species categories and that even resident species are not sedentary. The third chapter delves into more detail on nomadic birds on different continents, in particular examining how rainfall influences their movements. This chapter also presents a list of families in which nomadic species occur, with sandgrouse (Pteroclidae) and larks (Alaudidae) being strongly represented. Diet is considered to be the determining factor in nomadic species, and species dominance differs considerably between the arid ecosystems of the Old World, the New World and the Australian desert. Chapter 4 investigates habitats used by nomadic birds and how their densities vary. Rainfall stimulated events play a lead role in bird density in arid environments, enabling large numbers of birds to move into areas when resources are sufficiently abundant. Chapter 5 takes the topic further, providing an in-depth account of types of food, foraging techniques and how nomadic birds track resources that vary dramatically in time and space. A high proportion of nomadic dryland birds are either granivorous or insectivorous species, whereas frugivores and nectarivores are not wellrepresented. The effect of nomadism on breeding and moult is the topic of the penultimate chapter. Nest sites and materials, breeding seasonality, clutch size and nestling periods, breeding success and moult are dealt with under separate headings. The ephemeral nature of resource abundance plays a key role in the breeding strategies of nomadic birds. The breeding season is longer than that of resident birds and success rates are lower and more variable. The concluding chapter discusses the conservation of nomadic birds. While no nomadic species are listed as threatened in Red Data books, very little is known about their life-history parameters and equally little is known about ecosystem processes at the landscape level in arid areas. Changes in land use have adverse as well as beneficial effects on nomadic birds particularly in semi-arid areas where artificial water points increase densities of other animal species and consequently increase the competition for scarce resources. Comprehensive lists of bird families occurring in the arid zones of the world and of nomadic bird species which breed in arid zones, are included as appendices to the book. A 17page reference list provides the reader with more than enough scope to read further about this fascinating topic and a subject index, including common and scientific names of birds, provides quick access to species discussed in the text. The book is illustrated with numerous black-and-white photographs and figures from published and unpublished sources. The style of writing is factual and the book is based largely on published literature but supplemented with Richard Dean’s extensive experience in the Karoo. This book is a very useful review of an apparently poorlyresearched topic.

Nomadic Desert Birds

A baseline survey of lesser kestrels Falco naumanni in central Turkey

Habitat and potential prey surrounding lesser kestrel Falco naumanni colonies in central Turkey

Much of the Pembrokeshire coast and islands, together with its inshore waters, are of international importance for their breeding seabirds and wintering seaduck. Although the Sea Empress oil spill occurred before the breeding season, some 7000 oiled birds were recovered dead or alive. The impact of the oil spill on birds can be classified as follows: immediate mortality especially of more than 4500 wintering common scoter in Carmarthen Bay; sublethal effects on productivity of colonies and reduced adult survival from oil or dispersant ingestion; and chronic effects on bird populations from long-term pollution, particularly of prey. A range of monitoring and research projects are under way to investigate the impact, but it is premature to provide many results. The oil spill probably caused significant local declines in seabird colony sizes, especially of guillemot. The impact on common scoter will prove difficult to determine because of the poor quality and high variability of preincident data. La...

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Stephen J. Parr

Papers

A baseline survey of lesser kestrels Falco naumanni in central Turkey

Habitat and potential prey surrounding lesser kestrel Falco naumanni colonies in central Turkey

The impact of the sea empress oil spill on birds of the pembrokeshire coast and islands