Collectively, all human beings, including Americans, are playing a crucial role in the sixth major extinction event to occur in the course of more than three billion years of life on Earth, and the first in the past 65 million years. Species are being driven to extinction thousands of times faster than new ones can evolve. During the history of the United States, more than 500 of its known species have been eliminated (half of these since 1980) by various causes, including destruction of habitat by human activities or invasive species. Each of these species was associated with dozens of additional, mostly unnamed and unstudied, species that were wholly or partially dependent on it, so that the actual number of life forms lost is much greater.

Invertebrates are a part of nearly every food chain, either directly, as food for fishes, amphibians, reptiles, birds, mammals, or indirectly, as agents in the endless recycling of nutrients in the soil. Food webs are often dependent on invertebrate species performing essential services such as pollination or seed dispersal. Simply put, a world without invertebrates would be impoverished, and ecosystems would collapse.

Over the last few decades, a new paradigm has emerged: Improving and protecting our environment is compatible with growing the Nation’s economy. As part of this paradigm, we have come to recognize the essential linkage between the economy and the environment. We now understand that the sustained bounty of our Nation’s lands and waters and of its native plant and animal communities is the natural capital on which our economy is founded. We also realize that a sound forward-looking economic strategy requires that we protect this natural capital, rather than damage it and then spend millions or billions of dollars attempting to recreate what Nature has already given us. To protect our natural capital, our Nation’s biodiversity and the ecosystems within which it thrives, we need to have an extensive and frequently updated environmental knowledge base. This knowledge base is required to evaluate alternative plans for managing biodiversity and ecosystems as we work to optimize the union between the environment and the economy.

Table of Contents
Bryophytes
Lichen
Epiphytes
Fungi
Vascular Plants
Arthropods
Mollusks
Amphibians
Mammals

See also:

• Teaming with Life: Investing in Science to Understand and Use America’s Living Capital, PRESIDENT’S COMMITTEE OF ADVISERS ON SCIENCE AND TECHNOLOGY (PCAST) Panel on Biodiversity and Ecosystems, March 1998
• Xerces Society "Why are invertebrates important?"
• The All Species Foundation
• Invertebrates of the Columbia River Assessment Area, PNW-GTR-512 by Christine G. Niwa, Roger E. Sandquist, Rod Crawford
• Marcot, Bruce, Classification of Key Ecological Functions (KEFs) as used to describe ecological roles of fungi, lichens, bryophytes, nonvascular plants, vascular plants, invertebrates, and vertebrates, in the inland West U.S.
  

Bryophytes are the rich green plants that we see painting our trees here in the Pacific Northwest and making them so unique.  There is a definite dearth of information about these plants.  Research is currently underway to see if the aquatic bryophytes could be used as biological indicators of river water pollution, and it looks as if they will prove useful in this respect.  (Lopez, J., Reteurt, R., Carbelleira, A. ‘Aquatic Bryophytes May Be of Value as an Indicator of River Water Pollution’. Ecology, Jan.1997, vol 78, num 1, p.261)

"Loss of bryophyte species could influence the function of ecosystems in a variety of ways. For example, Antitrichia curtipendula plays a 'keystone' role in mineral cycling and regulation of microclimate in the canopy. It also provides nesting sites for marbled murrelet and red tree vole. Loss of this species or other key species of bryophytes could disrupt ecosystem function." J2-12

"Mosses, liverworts, and hornworts (collectively referred to as bryophytes) are small, green, nonvascular, spore-bearing plants that have evolved a wide array of species well adapted to nearly every habitat on earth. About 170 species of liverworts and 450 species of mosses occur within the range of the northern spotted owl. About 20 percent of these species are endemic to western North America or to the Pacific Northwest (Lawton 1971).

"Old-growth forests may be essential to the continued existence of some bryophytes. Most species of bryophytes don't become established in stands before these stands attain 100 years of age, and they are best developed in stands 400 years or older. Epiphytic mosses and lichens can total up to 2.6 metric tons per hectare in old-growth Douglas-fir forests of western Oregon (McCune 1993). In the understory, mosses often comprise 20 percent of the biomass and 95 percent of the photosynthetic tissue biomass (Binkley and Graham 1981).

"Bryophytes provide food and habitat for a host of invertebrates (Russell 1979, Gerson 1982, Varga 1992) and vertebrates. They are a perennial source of organic material and function as efficient filters for trapping sediments. Marbled murrelet nest in moss mats in old-growth trees. Flying squirrels, birds, and mammals commonly use mosses to build their nests. Bryophytes also intercept, absorb, and buffer nutrients and water in the canopy and understory (Brown and Bates 1990). They play an important role in the dynamics of understory vegetation, as well as soil structure, soil stability, and interception and retention of water. Bryophytes are also a major component of the forest stream ecosystem, providing year-round habitat for a wide array of algal species, aquatic invertebrates, and amphibians."

Moss also holds about 10 times its weight in water, ... and acts as a natural sponge, a hydrologic buffer to help control the flow of water in forests. Some threatened species such as the marbled murrelet build their nests in moss mats. And the moss is habitat for hundreds of insect species. Moss may play an important role in nutrient cycling that is not yet fully understood.

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Lichen

Lichens are the plant-like life from - sometimes leafy, sometimes stringy - that we see littering the forest floor and hanging from trees in late-successional and old-growth forest of the Pacific Northwest.  Each side of a lichen is a different color.  One side is green and the other varies, but is usually white or black.  The lichen itself is a symbiosis of a photosynthetic algae, corresponding to the green side, and a fungus, the white or black side.  This is a very unique structure and helps the lichen to serve many purposes.  Several species fix atmospheric nitrogen, an element that is necessary for plant development.  When they fall to the ground and decompose, lichens act like fertilizer, making their nitrogen available for uptake by other plants.  This litter fall also servers to add organic material to soil, increasing its water holding abilities.  Lichens of all kinds are important members of the forest canopy system.  They help to capture fog and rain, retaining this moisture in the canopy for other plants to use.

Lichens are important to the animals of the forest as well.  They provide a major food source for flying squirrels and red tree voles year round, in addition to being the winter forage for deer, elk and mountain goats.  Lichens are used by forest birds and animals as nesting material.  They also contribute to the overall diversity of bird species by adding to the structural complexity of the forest canopy.  Aquatic lichens, which are found on rocks and in streams, create conditions suitable for aquatic invertebrate habitat. (Nadcarni, NM. ‘Diversity of Species and Interactions in the Upper Tree Canopy of Forest Ecosystems’. American Zoologist, Feb. 1994, vol 35, num 1, p.70)

Lichens act as "bioindicators."  Changes in lichen populations may help us monitor air quality and even global climate change.  Aquatic lichens are sensitive to acid rain, so they can be used as biological indicators of pollution.  Other lichens are effected by gasses such as sulfur dioxide, making them useful in judging air quality.

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Epiphytes

"Epiphytic lichens and bryophytes are a conspicuous and ecologically significant component of westside forest in the Pacific northwest, where their biomass can exceed three tons per hectare (McCune 1993, Neitlich 1993). These epiphytes can be divided into four groups based on their ecological roles: cyanolichens, 'alecteroid' or forage lichens, 'other' lichens, and bryophytes (McCune 1993). Cyanolichens, or nitrogen-fixing lichens, are the dominant epiphytes of old-growth forests where they constitute over half the total epiphyte biomass (pike et al. 1977, Rhoades 1981, McCune 1993, Neitlich 1993). They fix large quantities of atmospheric nitrogen (Pike 1978), making it available for plant uptake. Nitrogen-rich leachates from these lichens also serve as a base for complex food webs in the forest canopy (Carroll 1979). Epiphytes have other important functions in forest ecosystems, such a providing critical winter forage for mammals, serving as food and habitat for invertebrates, and providing nesting material for birds (Slack 1988, Rhoades 1994).

. . . the extent to which late-successional epiphyte species can withstand the microclimatic changes following logging is currently unknown . . .  We recommend an epiphyte litterfall survey of unmanaged stands throughout the Pacific northwest."

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Fungi

Recent research has shown that the Pacific Northwest old-growth forests hold the highest diversity of fungi species of any ecosystem on earth. Over 100 species of fungi are both associated with old-growth and endemic to the Pacific northwest.  Fungi, and the mushrooms associated with them, are integral parts of the forest ecosystem. Conifers may associate with thousands of mychorrizal fungi. The roots of the plant are tapped by the fungus and form a symbiotic relationship.  The fungus receives sugars that the plant manufactures, and in return, the mycorrhizal fungus allows the plant to receive needed nutrients and water by extending the surface area of the plant’s roots.

Page 168-9 of DSEIS for Survey and Manage Amendment to NWFP:

"Fungi are neither plants nor animals but are recognized as a separate kingdom of organisms, both in structure and function. The large number of macrofungi (a fungi with sporocarps large enough to be seen without a hand lens) in late-successional and old-growth forests, especially in uneven-age stand structure, reflects the complexity of the late-successional and old-growth ecosystems as well as, or better than, many other groups of organisms. Estimates indicate there are at least six species of fungi for every vascular plant species in a given temperate ecosystem (Hawksworth 1991).

"The fungal flora of the Pacific Northwest is extremely diverse. Of the 527 species of fungi that were evaluated as being closely associated with late-successional f rests, 109 (21 percent) are known to be endemic to the Pacific Northwest. This list of species represents only a small percentage of the macrofungi that occur in late-successional forests. If microfungi (fungi with small sporocarps that are seen only with a hand lens) were included, the list would be greatly expanded. For every group of fungi, there are many species, perhaps hundreds, in addition to those on the original list (see Table IV-A- 1, p. IV-213, in USDA et al. 1993).

"Fungi are essential to the functioning of forest ecosystems. Many of the forest fungi that produce large fruiting bodies (such as mushrooms, boletes, and coral fungi) have symbiotic relationships with vascular plants. The survival of most conifers and many flowering plants depends on associations with these mycorrhizal fungi for the uptake of nutrients and water (Trappe and Luoma 1992). Hypogeous fungi (fungi that fruit below ground) and certain mushrooms are important food for small mammals that, in turn, aid in spore dispersal. Saprobic fungi (fungi that live on dead or decaying organic matter) are a major component of all forest ecosystems, growing on recently fallen trees, well-decayed logs, litter, dung, etc. They play an important role in decomposition and nutrient recycling.

"Most macrofungi (mushrooms, truffles and allies) produce fruiting structures or sporocarps that are short-lived and ephemeral, seasonal in occurrence, and annually variable. Sporocarps for many species are produced only during a brief portion of the season, and may not be present at all in any given year….

"Another poorly understood facet of fungi is their population biology. Connectivity of populations is key to species persistence across a landscape because this allows for the exchange of genetic material between subpopulations, reduces inbreeding and prevents the accumulation of deleterious alleles in isolated subpopulations…. It is often assumed that spores are the main unit of dispersal and reproduction in macrofungi, however, vegetative reproduction is probably an alternative for many species (Peterson and Hughes 1999). Spores can be aerial dispersed or moved by animals, with obvious differences in implications for population connectivity. If spores are moved by air currents over large distances, then isolation of subpopulations is less likely than if an animal vector is required. Unfortunately, there is little specific data on dispersal mechanisms for macrofungi, although it is generally assumed that truffle fungi are dispersed by animals. Because of these factors, population isolation and connectivity cannot be specifically addressed in this analysis."

Hypogeous fungi, provide a food source for a host of small mammals, such as the Northern flying squirrel and the endangered red tree vole -- primary prey species of the northern spotted owl.

Saprobic fungi soften the interiors of snags and logs making them hospitable to many other forest dwellers, like birds, martens, and reptiles.

"Many late-successional and old-growth associated fungi benefit (if not require) the biological legacies that persist from old-growth stands, including coarse woody debris, habitat structures, and host species. Mycorrhizal require live hosts, including conifers and many species of vascular plants, which in turn depend on the fungi for uptake of nutrients and water." J2-14

“Many [microfungi] have potential for future use as medicinals and biological control agents.” FEMAT IV-78.

“The survival of most conifers and many flowering plants depends on their association with these mycorrhizal fungi for the uptake of nutrients and water.” FEMAT IV-78.

Fungi also harbor many worms and flies which provide food for birds and other animals.

There are at least six fungi species for every vascular plant species in temperate ecosystems. (Hawksworth 1991).

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Vascular Plants

The sheer size of some astounds and dwarfs us, and others cover the forest floor.  Vascular plants include seed-bearing plants (flowering plants and conifers), and spore-bearing forms such as ferns, horsetails, and clubmosses.  Our old-growth forests hold the most biomass of any system in the world , due in a large part to the bulk these plants add to the system.  (Fotheringham, Alan. ‘A Final Warning About the last Frontier”. McLeans, May 28, 1990, vol 103, num 22, p.64)

When the leaves fall to the forest floor as litter, they aid in soil development.  These plants create the structure of the forest , shaping both the forest canopy and the understory.  The animals use this diverse forest structure to find their niches and homes, the birds nesting in the branches while small mammals burrow in their trunks.  In the winter the plants of the forest provide thermal cover and forage to these same animals.  Humans, too, take advantage of the many uses of vascular plants.  They are collected for their uses medicinally, horticulturally, and as edibles.

The species found in this region are as varied as they are spectacular.  One of the more interesting vascular plants is the candy stick (Allotropa virgata).  This species is known as an epiparasitic mycotrophe.  This means that the candy stick is a non-green, non-photosynthetic plant that is, basically, a parasite of a parasite.  It receives nutrients by tapping the mycorrhizal fungi that, in turn, are using an associated vascular plant for uptake of their nutrients.  Not only is its life strategy unique, but the aptly named candy stick is visually impressive as well.  Its’  pink and white striped stems can grow over a meter in height.

Page 211 of DSEIS for Survey and Manage Amendment to NWFP:

"The largest and most dominant organisms of the late-successional old-growth forest ecosystem are the vascular plants, some of which grow taller than 300 feet and have lifespans greater than 1,000 years. Vascular plants create the structure of the forest and function as the primary producers, capturing sunlight through photosynthesis and converting their energy to foods consumed by animals and fungi. Ranging from the dominant conifers to the delicate ferns, vascular plants are defined as those that contain conducting or vascular tissue. They include seed-bearing plants (flowering plants and conifers), and spore-bearing forms such as ferns, horsetails, and clubmosses."

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Arthropods

"Habitat management mitigation measures would increase the likelihood of maintaining and improving current levels of biodiversity and function across the federal landscape. Because arthropods were rated by functional group, [the risk of extirpation] has significantly more serious consequences for arthropods than for those taxa that were rated as individual species. Loss of arthropod ecological function on federal lands would likely result in diminished productivity, and jeopardize sustainability of the system." J2-39.

"Arthropods are invertebrates with jointed legs, a segmented body, and an exoskeleton (an external supporting covering). They include insects, crustaceans, arachnids, and myriapods. Collectively, arthropods constitute over 85 percent of the biological diversity in late-successional and old-growth forests in the Pacific Northwest (Asquith et al. 1990). Arthropods assume numerous ecological roles that are crucial to ecosystem function. Lattin (pers. com.) estimates that there are between 20,000 and 25,000 described species of arthropods within the range of the northern spotted owl, and as many more yet to be described.

"Arthropods inhabit virtually every part of the coniferous forest ecosystem, including coarse woody debris, litter and soil layers, understory vegetation, canopy foliage, tree trunks, snags, and the aquatic system. The litter and soil of the forest floor are the site of some of the greatest biological diversity fond anywhere. The soil under a square yard of forest may hold as many as 250 species and 2 million individual mites from a single taxonomic group, as well as thousands of other mites, beetles, centipedes, pseudo scorpions, springtails, and spiders. Many of these species have not been described and most are poorly understood.

"The structure and function of temperate forest soils is largely determined by the dietary habits of soil arthropods. They are the basic consumers of the forest floor where they ingest and process massive quantities of organic litter and debris, from large logs to bits of moss (Lattin and Moldenke 1992). While the richness of arthropod species in late-successional and old-growth forests suggests a great number of different processes and functions, relatively little is known about how arthropods interact, survive, and contribute to ecosystem function.

"Arthropods in late-successional and old-growth forests are of concern for several reasons. First, many of the species are flightless, which means their dispersal capabilities are limited. In fact, little is known about the dispersal capabilities of these invertebrates. Second, their flightless condition is believed to reflect habitat stability and permanence of a long period and therefore they are susceptible to changes or disturbances to their habitat. Third, many of the old-growth forest associated species have disjunct distributions and are found only in undisturbed forests. They are often found only within the range of coniferous forests within the Pacific Northwest and are therefore endemic to this area. Fourth, arthropods are key to ecosystem function and may serve as indicators of ecosystem health. They are (1) a key element in the nutrient cycling of down logs, (2) major components in the litter and soil, (3) herbivores of the forest canopy, (4) pollinators of flowering plants, and (5) play important roles in aquatic systems. Lastly, many of the species native to this region have not been described or named, and the number of known species probably represents less than half of the number of species estimated to exist (Lattin and Moldenke 1992)."

The soil structure, in turn, is a basic determinant as to what sort of forest will grow in that location.  Arthropods also help the system by serving as check on each others populations through predation. (Lattin, J.D. Arthropod Diversity and Parasites of other Arthropod Species”. American Zoologist, Dec. 1993, vol 33, num 6, p.576)   Although there is still much to be learnt about these insects, it is obvious that a healthy ecosystem is dependent upon their existence.

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Mollusks

We have all seen these critters in the woods and in our backyards, but most of us have never stopped to contemplate the function that they might serve in the ecosystems we share.  Scientists are just beginning to realize the significance of this group.   They are a major source of biodiversity in the late-succsessional forests of the Pacific Northwest. Many of these animals make huge contributions to the decomposition of leaves into soil.  This aids in nutrient recycling as well. Eight of these mollusks that are associated with late-successional and old-growth forests are identified as candidates for listing on the Endangered Species List. The banana slug (Ariolimax columbianus), so common in this area, is one of the largest species in the world.

Page 216 of DSEIS for Survey and Manage Amendment to NWFP:

"Mollusks represent a major part of the biological diversity in late-successional forests of the Pacific Northwest. Mollusk species associated with Northwest coniferous forests include land snails, slugs, aquatic snails and clams. Mollusks may be found in a variety of habitat types. Land mollusks generally inhabit the forest litter and duff or low vegetation layers during suitably moist seasonal conditions. Many species require refugia such as large down wood, rocky outcrops, and moss-covered substrates that maintain relatively constant environmental conditions during cold or dry seasons. Some species (such as Vertigo) are primarily arboreal, while others (Monadenia) are partially arboreal and climb trees to forage, find suitable temporary cover, or escape from flooding. Local populations of slugs or snails are called colonies. Colonies vary from hundreds to tens of thousands of individuals, with colonies occupying areas ranging in size from tens to hundreds of square feet.

"As a group, mollusks are diverse in both the number of species and the roles they play in ecosystem functions. Some have very restricted geographic ranges and narrow ecological requirements. Scientists are still discovering new species in coniferous forests of the Pacific Northwest and estimate that the known fauna may eventually double (Taylor 1981, Frest and Johannes 1993). Currently, approximately 350 species of mollusks are known to occur in forests within the range of the northern spotted owl (Frest and Johannes 1993).

"Land snails and slugs account for more than 150 of the currently known fauna of 350 species of mollusks. Most are found in moist forest environments and riparian areas near streams, springs and seeps. Basalt and limestone talus outcrops are also important habitats for many species. Their present distribution has been influenced by a combination of geologic, hydrologic, climatic, and biotic history in the region. More than 100 mollusk species were identified as being associated with late-successional forests (USDA et al. 1993). Within the range of the northern spotted owl, particularly in the Columbia Gorge, southwestern Oregon and northwestern California, there are groups of mollusks that are endemic (found nowhere else). There are concentrations of endemic species in the land snail genus Monadenia, the slug genus Hemphillia, and the aquatic snail genera Fluminicola, Juga and Lyogyrus.

"Most mollusks are herbivores, detritivores and/or fungivores (Frest and Johannes 1993, Roth 1993). By consuming leaf litter, terrestrial snails and slugs contribute to nutrient cycling and soil productivity. Two slug species (Prophysaon coeruleu and P. dubiu ) consume the fruiting bodies and hyphae of forest floor fungi, and disperse viable spores and hyphal fragments in their feces (Duncan 1999). A few terrestrial mollusk species consume animal matter and fecal material, and several species (Ancotre a, for example) feed on other invertebrate species, including other mollusks. Many small mammals, and some birds and ground beetles consume land snails and slugs. Aquatic snails are herbivores and/or detritivores feeding on algae, bacteria and fungi growing on rocks, wood or submerged leaves (Brown 1991, pp. 293-295; Frest and Johannes 1993)."

Amphibians

Page 225 of DSEIS for Survey and Manage Amendment to NWFP:

"Approximately 32 species of amphibians are found in the Pacific Northwest, but fewer are found in coniferous forests. The amphibian fauna of the Pacific Northwest includes 20 species that are endemic to, or have a majority of their ranges within, the Northwest Forest Plan area. The Pacific Northwest supports the second highest number of amphibian species in the United States, second only to the southeast.

"Amphibians are functionally important components of coniferous forests in the Pacific Northwest. Amphibians, particularly salamanders, can reach high densities in forest ecosystems. Larvae, juveniles, and adults may function as predators or as a major food source for other vertebrate species and invertebrates.

"Amphibians are particularly sensitive to environmental change because their complex life cycle exposes them to hazards in both aquatic and terrestrial environments. Most of the species require cool, moist conditions to maintain respiratory function. Stream dwelling species generally require cool water, and are sensitive to sedimentation that can inhibit reproduction and foraging. Within locales in the Pacific Northwest, populations of several species of amphibian have been extirpated, and the ranges of numerous species have been drastically reduced. Most declines have occurred in forest-dwelling species."

Abstract  Salamanders are cryptic and, though largely unrecognized as such, extremely abundant vertebrates in a variety of primarily forest and grassland environments, where they regulate food webs and contribute to ecosystem resilience-resistance (= stability) in several ways: (a) As mid-level vertebrate predators, they provide direct and indirect biotic control of species diversity and ecosystem processes along grazer and detritus pathways; (b) via their migrations, they connect energy and matter between aquatic and terrestrial landscapes; (c) through association with underground burrow systems, they contribute to soil dynamics; and (d) they supply high quality and slowly available stores of energy and nutrients for tertiary consumers throughout ecological succession. Salamanders also can provide an important service to humans through their use as cost-effective and readily quantifiable metrics of ecosystem health and integrity. The diverse ecological roles of salamanders in natural areas underscore the importance of their conservation.

Robert D. Davic, Hartwell H. Welsh, Jr. 2004 (in press). On the Ecological Roles of Salamanders. Annual Review of Ecology, Evolution, and Systematics. First posted online on July 26, 2004. Expected online publication date for the Annual Review of Ecology, Evolution, and Systematics Volume 35 is November 9, 2004. See http://www.annualreviews.org/

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Mammals

"The presence of arboreal rodents, keystone species, provide a prey base for many vertebrate predators and enhance ecosystem function through fungal spore and seed dissemination (Carey 1991)."

Small mammals aid in the workings of the ecosystem in a myriad of ways, but they seem to specialize in the aiding of dispersal of otherwise less mobile wildlife.  Hypogeous fungi rely on these animals to eat them and then deposit their spores throughout the forest in their fecal pellets.  Seeds of many berries and other plants are aided in the same way.  The animal waste also adds nitrogen and active yeast to the forest soil, both fertilizing and aiding in nutrient cycling.  Small mammals carry lichens and physically distribute them over the entire forest.  These animals also make up the main source of prey for the northern spotted owl.

The red tree vole, a major prey species for the Northern spotted owl, (Phenacomys longicaudus) of the Pacific Northwest is a great example of the variety of mammal species offered in this region.  It is unique among mammals in that it spends most of its life in the canopy of coniferous trees.  The red tree vole relies on the fresh green foliage and moisture it is assured in this environment.  It’s also the decreased temperature range in this part of the forest that attracts this small mammal. The red tree vole is a major prey species for the Threatened Northern spotted owl.  Their nests are used for several generations, eventually getting as big as 1 meter by 1meter.

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