Conservation of Biodiversity

Highlights

Over 400 species of plants and animals rely on BC’s old growth forests for at least part of their life cycle. As of February 18, 2022, 326 species (plants, animals, birds, etc.) have been sighted and recorded in the Fairy Creek watershed, including 17 species that are at risk.
Few vascular plantA vascular plant has specialized vascular tissue. There are two types of vascular tissue: xylem and phloem, which move water, nutrients, and the products of photosynthesis throughout the plant. Vascular plants include trees, seed plants and ferns. species are confined to old growth forests, but old forests are optimum habitat for many species including several saprophytic plantsUnlike typical green plants saprophytic plants lack chlorophyll in their leaves and so are unable to produce food from the process of photosynthesis. Instead, they feed on the decay of dead plants and animals. and lower plant species including mosses, lichens, liverworts, algae, and bacteria, and some probably require such habitat for survival. The rich communities of epiphytesEpiphytes are plants, including lichens, which rely on other plants for support, growing on trunks and branches rather than rooting themselves to the ground. They are not parasitic on the supporting plants but rather derive nutrients from the air and small pools of water that collect on the host. Epiphytes are also referred to as epiphytic plants. found in old growth canopies include some lichens seldom found elsewhere.
Clearcuts often support more plant species than old forests but many species in clearcuts are common, invasive, shade-intolerant herbs. Old growth forests may support species that are uncommon or absent in regenerating and immature forests.

Number of species in old forests

More than 400 species of plants and animals rely on BC’s old growth forests for at least part of their life cycle (). As of February 18, 2022, 326 species (plants, animals, birds, etc.) have been sighted in the Fairy Creek watershed and recorded on the Fairy Creek Research page in the iNaturalist website. Given that observations are concentrated in the accessible lower part of the watershed, these numbers are likely very conservative estimates of the total number of species there. A systematic survey of the species found at Fairy Creek has not been done by government or indus

Plant species unique to old growth

Few species are found only in old growth forests. For example, none of the plant species in Douglas fir-western hemlock stands at the H.J. Andrews Experimental Forest in the United States are confined to old-growth forests (Dyrness et al., 1974, cited by ). However, old forests are optimum habitat for many species including several and lower plant species including mosses, lichens, liverworts, algae, and bacteria, and some probably require such habitat for survival (). The rich communities of found in old growth canopies include some lichens seldom found elsewhere.

There are substantial differences in composition and relative abundance of plant species between young and old growth forests. Young regenerating stands (3-9 years old) sampled in a chronosequence studyA chronosequence study in forest sciences is a study that takes place on a set of forested sites that share similar attributes (e.g., climate and topography) but are of different ages in the CWHvmCWHvm is the abbreviation for the very wet maritime Coastal Western Hemlock biogeoclimatic subzone. The province of British Columbia is divided into 16 zones, including the Coastal Western Hemlock (CWH). A zone is a large geographic area with a relatively uniform regional climate. The CWH zone is subdivided into climatically distinct subzones, including the vm, or very wet maritime subzone. The CWHvm has a wet, humid, mild, oceanic climate and has an extensive distribution on the BC coast including western Vancouver Island. subzone on western Vancouver Island supported far more plant species (152) than later stages (about 80 species for old growth) (Ryan et al., 2009Ryan, M.W., Fraser, D.F., Marshall, V.G., He, F. 2009. Successional changes in plant species diversity in forest chonosequences on southern Vancouver Island. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Information Report BC-X-421. 13 p.). They found 63, 17, 4 and 9 plant species unique to 3–9-year-old, immature, mature, and old growth stands, respectively. Much of the decline in total and unique species with stand age arose from the high number of common, invasive, shade-intolerant herbs that colonized regenerating clearcuts but cannot exist under a canopy. In contrast to the herb-dominated clearcuts, bryophytesBryophytes are non-vascular seedless land plants (mosses, liverworts, and hornworts). Although they exhibit specialized structures for water transportation, they have no vascular tissue or true roots. and lichens made up about half of the species in the older forests, and most occurred on coarse woody debris and rock substrates. The plants unique to old growth were all cryptogamsCryptogams are plants that have no true flowers or seeds and reproduce by spores. They include mosses, liverworts, and lichens. Ferns are considered advanced cryptogams because they reproduce by spores but are differentiated into roots, stems and leaves. Read more about cryptograms., namely, the liverworts Bazzania tricrenata, Herbertus aduncus, Kurzia sylvatica, Odontoschisma denudatum, Porella cordeaena, and Radula bolanderi, and the mosses Buxbaumia piperi, Hypnum dieckii, and Plagiothecium laetum.

noted that while old growth forests do not necessarily maintain larger number of plant species than young successional stages, they may support species that are uncommon or absent in regenerating and immature forests. They suggest that using species richness or other quantitative measurements of species diversity as the sole basis by which to direct conservation efforts is misguided, because they fail to distinguish between widespread or introduced species and uncommon or rare species.

Vertebrate animals unique to old growth

More is known about the relationship of vertebrate animals to old growth than other group of organisms. The degree to which vertebrate species require old growth varies, but many find optimum breeding or foraging habitat there. Some species may be found in younger age classes as well as old growth, but it is not known whether they will survive if the major reservoir of optimum habitat is gone.

Maintenance of biodiversity

Risk to biodiversity is high for most high ecosystems across BC (). International targets call for countries to protect a minimum of 17% of “ecologically representative” terrestrial areas “of particular importance for biodiversity and ecosystem services” by 2020 (; Watson et al., 2016). While this applies to countries rather than provinces, BC is Canada’s most biodiverse province and so bears a large obligation to meet Canada’s target. Highly productive ecosystems have particular importance for both biodiversity and various ecosystem services (; ), thus they should be at least as well represented as other ecosystems. Price et al.’s (2020) analyses suggested that for BC to meet the target it would need to designate much more high-productivity land for conservation. Currently only 10% of the area of forest with the potential to grow large trees is protected, and only a fifth of that area is old. Protecting an additional 355,000 ha of high-productivity forest would meet the 17% target. All the remaining highly productive unprotected old growth would have to be protected to meet this goal.