Science

Many environmentalists and conservation biologists enjoy riding mountain bikes. Mountain biking is often perceived as a low-impact pursuit, more like hiking, backpacking, and paddling than motorized four-wheeling or dirt biking. However, there actually isn't much evidence to support this intuition.

Deep in the oak and birch forests of the Sikhote-Alin State Biosphere Zapovednik, a Siberian tiger quietly stalks a herd of sika deer. She is one of the fewer than 400 remaining members of this wild subspecies, Panthera tigris altaica, and is lucky to live in pristine, unfragmented habitat in the Russian Far East where she finds lots of prey and few humans. Habitat loss, fragmentation, and poaching have already led to the extinction of three out of eight tiger subspecies worldwide.

Remember the days of sweating and climbing up steep slopes to gain spectacular views and relish the sounds of silence? Silence is not so easily won these days, even in remote wilderness.With the aging and relatively affluent baby-boomer market, helicopter recreation is one of the fastest growing types of wilderness adventure. Heliskiing, heli-hiking, heli-site seeing, and heli-fishing are all forms of helicopter recreation and along with the increase in human activity in wilderness, they raise concerns about impacts to wildlife populations.

A Varied Response

The number of seismic tests for oil and gas conducted on public lands in the United States is increasing, and this should concern anybody interested in conserving wildlife, plants and vegetation, soil, and the very character of these lands. As domestic oil and natural gas exploration increases, geophysicists seek to map and understand underground deposits that may hold valuable hydrocarbon resources.

The study of road impacts upon wildlife has ignited in the last decade, but only in the past few years have efforts begun to mitigate these impacts. Engineers and biologists are now working jointly to design operative wildlife underpasses and overpasses that will temper the effect roads have upon wildlife. Effective crossing structures will help to reconnect areas of viable habitat that have become isolated due to road construction. This is an arduous task if you consider the wide-ranging species in the world, their diverse biological needs and habitat requirements.

The impacts of railroads on wildlife and wildlife habitats are not much different from those caused by roads. Loss of habitat, mortality due to collisions, barrier effect and reduction in habitat quality are the main impacts of habitat fragmentation by railroads. This may cause reduced population viability or threaten a speciesø survival. On a local scale, trains affect wildlife habitats through the introduction of exotic plant species (e.g. seeds), emission of toxic contaminants like heavy metals, or management (e.g. herbicides).

Death between the tracks

Sand dunes are a biologically unique fraction of arid land ecosystems (Bury & Luckenbach 1983). They serve as îhabitat islands" for numerous species of vegetation and wildlife. The Oregon Dunes National Recreation Area, for example, teems with life, encompassing 42 different ecotones. The same is true of the dunes of Back Bay, Virginia where yellow sand is crowned with sea oats and nesting birds. Compared to those, the dunes of California seem devoid of life.

Arthropods make up a significant part of the biodiversity on this planet, and are important in many ways to the overall health of ecosystems and to our understanding of natural biotic systems. At the base of many food chains, arthropods are important components of the diets of invertebrates and birds, and are also an integral part of the nutrient- and energy-processing abilities of the soil (Coleman & Crossley 1996). Arthropods also tend to demonstrate opportunism and rapid response to change.

Wildfire is an essential ecological process. Yet when fundamental components of an ecosystem are out of balance, the occurrence of wildfire may fall out of balance as well (though large, stand-replacing fires have always occurred). The summer of 2000 demonstrated this, as millions of acres of public and private land in the western United States burned. Many are naturally concerned with the ecological, economic and social impacts of these fires. Few question, however, the ecological consequences of the aggressive tactics fire suppression agencies use to control them.