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This chapter discusses the montane and subalpine coniferous forests and other vegetation of the Sierra Nevada and Cascade Ranges in California, vegetation patterns and environmental factors that affect distribution, and the role fire in spatial pattern and landscape. It also discusses some of the factors affecting vegetation, such as insects and pathogens, wind and avalanches, invasive species, air pollution, and logging.

The structure of a community is an important factor in the stabilization of food web composition and the regulation of ecosystem processes. Nevertheless, surprisingly little is known about temporal and spatial variability in community and food web composition, and the underlying mechanisms that cause this variability. Moreover, the question remains of how important spatio-temporal variability in community structure is for the regulation of soil processes, and whether we need this kind of detail to understand underlying mechanisms. In an attempt to answer this question, a terrestrial example, the organic horizon of a coniferous forest soil, will be used (1) to quantify community variability in time and across space and (2) to assess possible consequences of community variability for an important soil process, the degradation of organic matter and the subsequent flow of energy and nutrient through soil.

This chapter considers the mammals and birds in coniferous forests, including shrews, mice squirrels, rodents, moose, elks, deers, foxes, bears, and crossbills. All warm-blooded animals need food and shelter, and some find what they need, in whole or in part, in coniferous forest. The most dependable food supplies are seeds and browse for the herbivores. For the carnivores, there are worms, sowbugs, insects, spiders, any vertebrate animals that they can catch and kill, and accessible birds' eggs. Shelter is needed for four purposes: for breeding, for sleeping and resting, for shelter from bad weather, and for concealment. Evergreen trees, both live and dead, provide for these needs. The animals considered in this chapter are not in a conifer forest by chance but because it supplies their needs.

This chapter maps the geographic extent of the ecosystems created by conifers, and coincidentally the areas of dominance of one or more identifying conifer species. The result is a mosaic of “regions.” In all the regions except the Great Lakes, the St. Lawrence, and the Acadian, conifers dominate. The forests of the latter two regions vary between coniferous and mixed (that is, with various broadleafs as well as conifers). The trees that are found at any one site depend mainly on the climate, the terrain and soil, the location from which their ancestors immigrated, and the number of years since the site was last burned. In mountainous country, elevation is another important factor.

This chapter looks at the ecosystem of the forest floor. The forest floor consists chiefly of soil. One of the most distinctive soils is podsol, the typical soil in conifer forests. This soil is easily recognizable if you expose it by digging a hole, or even more easily by seeing it exposed in an eroding stream bank. It has a thin, dark top layer of packed needle-leaf litter gradually decaying into humus (newly decomposed material with organic ingredients only). Immediately below that is a layer, often thick, of almost pure white sand. The soil is cold, acidic, and sometimes wet. The most common flowers on the coniferous forest floor belong to three families: one, of plants that prefer acid soil; a second, of epiparasitic plants; and a third, of ancestors of the epiparasites. The remainder of the chapter discusses the floor of the boreal forest; the value of dead wood and debris; and animals found in the evergreen forest—beavers, birds, and ducks.

This chapter focuses on the interactions between coniferous trees and nonliving things: fires, snow and wind, air pollution and acid rain, and logging. Fire is essential to forest renewal. Like decay, fire disposes of dead vegetation. Without fires the forest floor would become an impenetrable tangle of fallen trees, broken branches, and withered and rotting vegetation of all kinds. While ordinary snow is no threat to an evergreen, an avalanche in the mountains can take out hundreds of trees in seconds. Toxic gases are released into the atmosphere by industries burning fossil fuel. These affect forests by dissolving in falling rain and acidifying it. This kills much of the aquatic life in lakes and ponds and affects the water from which the trees obtain mineral nutrients. Conifers are more vulnerable than broadleafs. Their growth is slowed, their reproduction reduced, and their death rate rises. Affected trees are also thought to become more susceptible to pests and diseases.

This chapter focuses on broadleafs that can be found in northern forests. It considers the trees and shrubs that live in the harsh climate of the true north, not those in the mixed forests of the St. Lawrence valley and southern Great Lakes where climate and soils are hospitable to many broadleafs. The broadleafs play an important part in the coniferous forests. They belong to four genera: the willows (Salix), the poplars (Populus), the birches (Betula), and the alders (Alnus). Shrubs as well as trees of these genera are common in the evergreen forests. All have catkins, which consist of densely packed rows of flowers growing along a short stalk that may be upright or dangling. The individual flowers are tiny and devoid of petals.

The aim of this chapter is to provide an account of the complex history of Mediterranean faunas as they evolved from the end of the Pliocene about 1.8 million years ago until the present day. Reconstructing this history is difficult because the Mediterranean basin is one of the most complex regions in the world and is characterized by significant geographical and topographical variation. The Mediterranean basin was formed during the Tertiary by the convergence of the African and Eurasian tectonic plates, in combination with several African microplates, Iberia, and two main African promontories: Apulia in the west and Arabia in the east (Chapter 1 and Dercourt et al. 1986). Where the African and Eurasian plates meet, seismic and volcanic activity have combined with other processes to form a very heterogeneous region. High mountains and deeply dissected topography form the main part of a coastline some 46,000 km in length, 18,000 of which are island shores (Chapter 13). A dominant feature of the region, which has had many consequences for species diversity and the process of differentiation, is the striking contrast between the northern half of the basin with its many large peninsulas—Iberian, Apennine, Balkan, and Anatolian—and the southern half with its more or less rectilinear shorelines. In addition, there is a marked biogeographical contrast between the western and the eastern halves of the Mediterranean, the former having shifted somewhat to the north with respect to the latter. The line separating the two north–south ranges in each half of the basin runs approximately along the 36th parallel in the western half and the 33rd in the eastern half. In the western half, west of the Sicily–Cap Bon line, biota are more boreal in character and overlap to a large degree with those of central Europe. To the east, biota have more affinities with central Asia (Blondel and Aronson 1999). Modern patterns of regional floral and faunal diversity mostly result from differential speciation and extinction rates during the Quaternary (Chapter 4).