Biotic Interactions in Arid Lands

The exigencies of life in the desert environment have resulted in the se lection of a diversity of adaptations, both morphological and physiologi cal, in the flora and fauna. At the same time, many plants and most small animals are able not merely to exist but even to thrive under desert conditions - mainly by avoiding thermal extremes and by the refine ment of pre-existing abilities to economise in water. In the same way, the biotic interactions of the flora and fauna of the desert do not involve many new principles. Nevertheless, conditions in arid regions frequently do invoke refinements of the complex interrelations between predators and their prey, parasites and their hosts, as well as between herbivores and the plants upon which they feed. In this book, I shall discuss not only such interactions and their feedback effects, but also community processes and population dynamics in the desert. The physical conditions of the desert that principally affect predators and their prey are its openness and the paucity of cover. This is re stricted to scattered plants, occasional rocks, holes, and crevices in the ground. Furthermore, nightfall does not confer relative invisibility, as it does in many other ecobiomes, because of the clarity of the atmosphere. The bright starlight of the desert renders nearby objects visible even to the human eye, while an incandescent moon bathes the empty landscape with a flood of silver light. Consequently, adaptive coloration is func tional at all hours of the day and night.

Klappentext

This book is a basic account of the synecology of deserts. It covers a wide range of topics that have been studied extensively in other biomes, but not yet in arid lands. These include predation and anti-predatory strategies, parasitic and allied interactions, herbivory and plant defences. Finally, community processes such as communal and social behaviour among animals, aggression, population effects, pollination, seed dispersal, competition, and food webs, are discussed. By drawing attention to both what is and what is not known with regard to desert ecology, a basis for future research is provided.

Inhalt
1 Introduction.- 1.1 Evolutionary Parallels.- 1.2 Ecological Analogues.- 2 Predatory Techniques.- 2.1 Active Searching for and Stalking Prey.- 2.2 Ambushing and Disguise.- 2.3 Scavenging.- 2.4 Synchronization of Activities.- 3 Primary Anti-Predator Devices.- 3.1 Anachoresis.- 3.2 Burrows and Retreats.- 3.3 Rhythmic Activity and Phenology.- 3.4 Crypsis.- 3.5 Protective Resemblance and Disguise.- 3.6 Mimicry.- 3.7 Integument, Scales and Armour.- 3.8 Aposematic Coloration.- 3.9 Communal Behaviour.- 3.10 Vigilance.- 4 Secondary Anti-Predator Devices.- 4.1 Flight and Escape.- 4.2 Thanatosis.- 4.3 Deflection of Attack.- 4.4 Autotomy.- 4.5 Spines, Urticating Hairs and Gin Traps.- 4.6 Venoms, Defensive Fluids and Toxins.- 4.7 Warning Smells, Sounds and Deimatic Display.- 4.8 Retaliation.- 5 Parasitic and Allied Interactions.- 5.1 The Parasites of Plants.- 5.2 Ectoparasites.- 5.3 Endoparasites and their Transmission.- 5.4 Parasitoids.- 5.5 Kleptoparasitism and Slavery.- 5.6 Social Parasitism, Commensalism and Mutualism.- 5.7 Evolutionary Trends in Parasitic Relationships.- 6 Plants and Herbivorous Animals.- 6.1 Vegetative Crypsis, Mimicry and Deception.- 6.2 Chemical Deterrence.- 6.3 Toughness and Spines.- 6.4 Responses to Seed-Eating.- 6.5 Thermal Protection.- 6.6 Symbiotic Protective Relationships with Stinging Insects.- 6.7 Phenology.- 7 Community Processes.- 7.1 Protection of Young and Social Behaviour.- 7.2 Effects on Animal Populations of Parasites and Predators.- 7.3 Sequestration of Plant Metabolites.- 7.4 Pollination of Plants by Animals.- 7.5 Seed Dispersal by Animals.- 7.6 Cooperation Between Plants.- 7.7 Competitive Interactions.- 7.8 Food Webs.- 8 Discussion and Conclusions.- 8.1 Emerging Principles.- 8.2 Desert Ecosystems.- References.