5.Biodiversity Issues in the Thompson-Okanagan

5.1 Introduction

British Columbia is the most biologically diverse province or territory in Canada. British Columbia is home to 143 mammal species, 454 birds, 20 amphibians, 19 reptiles and 450 species of fish. There are approximately 2,850 vascular plants, 1,600 lichens, 522 species of attached algae, and over 10,000 fungi species. It is believed that number of insect species range from 50,000 to 70,000. Some of these species are not found anywhere else in Canada. Of all species native to the country, 9 % of the birds, 12 % of the reptiles, 17 % of the mammals, 27 % of the amphibians and 25 % of the freshwater fish are exclusive to British Columbia. The biodiversity of British Columbia is not only significant to Canada, but it is also significant on a global scale. British Columbia is home to a significant portion of global populations of mountain goats, blue grouse, trumpeter swans and grizzly bears.

The diversity of British Columbia varies across the province. The Okanagan Valley is a part of the Southern Interior Ecoprovince . In this region, low levels of precipitation, hot summers and mild winters provide a habitat for species that are unique both to British Columbia and Canada. For example, of the 20 species of bats found in Canada, fifteen are present in the south Okanagan and two are exclusive to this area. Like the rest of the world, however, the diversity of this area is threatened by human population growth and the following specific problems:

• Growing populations have threatened and endangered many species and habitats in the Okanagan. Only 9 % of the natural grasslands native to the Okanagan remain, due to roads, malls, orchards and housing developments expanding into undisturbed land.

• Fire suppression is changing the biodiversity of the Okanagan. Many of the low elevation areas are believed to be fire-induced ecosystems. In other words, in a natural setting, periodic fires maintain the proper species composition. With controlled fires, higher plants, such as trees, succeed the native vegetation and cause their competitive exclusion.

• The introduction of new species threatens many species in the Valley. Over the past few decades several species have been introduced, mainly accidentally, which are causing havoc for native species. Eurasian Milfoil , Purple Loosestrife and Knapweed are three foreign species that have become well established in the area during last 30 years. In Okanagan Lake, the introduction of Mysis shrimp by the Ministry of the Environment may be partially responsible for population declines of Kokanee . Exotic species that are relatively new to the area include Leafy Spurge , Rush Skeleton Weed , Yellow Starthistle , Dalmatian Toadflax and Sulphur Cinquefoil . The provincial government is attempting to control these species and prevent their establishment like Eurasian Milfoil and Knapweed.

• Livestock grazing has also had a major impact on the biodiversity in the Okanagan. Overgrazing can disturb the soil and natural vegetation and allow perfect conditions for the invasion of like Knapweed . Livestock can also affect the water supply in temporary pools that supports a variety of small species.

• Recreation and Traveling. There are a high number of wildlife killed each year on Okanagan roads reducing populations. It is estimated that 3,000 deer are hit and killed each year in the Valley. Off-road vehicles disturb sensitive wildlife and soils and allow for the invasion of weeds. Although sport hunting is controlled with licenses and regulations, there is still a problem with poaching in the area. Deer, moose, elk and bear are several species that are illegally killed in the Okanagan for sale on the black market.

5.2 Reduction in the Kokanee Fishery

5.2.1 Introduction

Kokanee (species - Oncorhynchus nerka ) are a unique form of sockeye salmon that were landlocked following the last ice age. In North America, natural populations occur in Alaska, Yukon Territory, British Columbia, Washington, Idaho, and Oregon. In the past, Kokanee have been a traditional food for native Indians of these regions. More recently, Kokanee have become a popular sport fish.

Kokanee typically complete their life cycle, which varies from three to five years, in the lakes and tributaries in which they were born. Mature adult Kokanee spawn either in streams and rivers or near the shores of lakes during the late summer to early fall.

5.2.2 Okanagan Lake Kohanee

Kokanee populations is some Thompson-Okanagan lakes have undergone dramatic losses in numbers. One such lake showing a decline in kokanee nimbers is Okanagan Lake. Declining numbers are most often noted in the number of Kokanee that spawn each year. In the 1970s, estimates suggest that about one million Kokanee spawned in Okanagan creeks each year. By 1994, this number declined 10 % of this value.

There are a number of factors responsible for the decline in Okanagan Lake Kokanee numbers. Many of these factors destroy Kokanee spawning habitat. Scientists believe that of all Okanagan spawning habitat that existed 100 years ago, only 10 to 20 % remains today. Declining Kokanee populations are thought to be due to:

Over-fishing. It has been suggested that Okanagan Lake has been over-fished to a point where the Kokanee population has dropped, although this is not well documented. Over-fishing has likely played a part in the Kokanee fishery collapse, but it has probably been minimal. In 1988, biologists estimated that over 200,000 Kokanee were caught from Okanagan Lake. Normally this number would be acceptable for a lake the size of Okanagan, but with such limited spawning habitat, this count is considered very high. A similar situation occurred in the west arm of Kootenay Lake during the mid-to-late 1970s. The fishery there was many times larger than that of Okanagan Lake. In a study of the fishery collapse, over-fishing did appear to have a major effect, but several other factors contributed to the decline.

Logging Activities. Logging mainly affects Kokanee populations by impacting their spawning grounds. A number of stream characteristics, important to Kokanee, may be altered due to logging practices.

a) Logging alters stream flow hydrology. Logged areas tend to have decreased fall and winter flows and sudden rapid spring freshets (runoff), when compared to undisturbed areas. This means that fish eggs can dry out, be exposed to freezing, or be flushed out prior to hatching.

b) Logging and its' associated activities, such as road building, can cause increases in stream sediment loads. Clear-cuts can cause increases in sediment loads due to mudslides and debris flows. Increased sediments may ruin spawning grounds by "choking" them out with fine particulate matter.

c) Logging practices can affect water quality, including temperature, water chemistry and dissolved oxygen concentration. Salmonid fishes, such as Kokanee, require pristine spawning conditions which include cold, clean, well-oxygenated water. Lethal temperatures are often achieved in streams that have had their riparian (streamside) vegetation removed. This has been observed in Mission Creek, one of Okanagan Lake's major spawning channels. Improper logging techniques may result in increased nutrient loading in streams and decreased oxygen availability for Kokanee eggs.

Stream Modification. Many tributaries (streams) of Okanagan Lake have undergone some form of stream modification in recent decades. For example, the Okanagan River was diked and channeled during the late 1950s in an effort to reduce flooding in the Penticton area. Mission Creek in Kelowna was also channeled for a major portion of its lower reach. This resulted in effective flood control. Stream modification destroys Kokanee spawning habitat in several ways.

a) Channeling results in the scouring away of the spawning substrates. Good spawning substrates, consisting of small, unconsolidated rock and gravel, are replaced with larger rocks and boulders, which are useless to Kokanee.

b) Streamflow is altered so that suitable spawning areas are dry by the time spawning takes place, or shortly afterwards, resulting in high Kokanee egg mortalities. In other areas, stream flow is concentrated so it is too fast for the Kokanee to efficiently spawn. During spring freshets (runoff), boulders can crash over the spawning grounds due to increased stream velocities in the channels.

c) Channeling results in the destruction of riparian vegetation along modified streams. This decreases stream shading, resulting in higher temperatures in the fall, and much lower temperatures in the winter. These temperatures may be lethal to delicate Kokanee eggs.

Lakeshore Development. Although shore spawning Kokanee are not well documented, lakeshore modification has likely affected their numbers. The development of lakeshore has resulted in the destruction of spawning beds along it. Man-made beaches and road-building alongside the lake have probably destroyed much of the habitat for shore-spawning Kokanee.

Water Use. The Okanagan Valley relies heavily on water for agricultural and domestic uses. Several streams have significant amounts of water removed for these purposes. In addition, many streams travel through residential areas where storm sewers empty into them. These uses have negatively affected Kokanee spawning habitat.

a) It is not uncommon to see streams that contain prime spawning habitat become reduced to a trickle by the end of the summer (when the Kokanee spawn). The lack of water leads to higher temperatures in the fall, which are also detrimental to Kokanee and their eggs. This situation has repeatedly occurred at Trout Creek, Summerland, for several years.

b) Other streams are frozen during the winter months because water flow is minimal, killing Kokanee eggs.

c) Low flows promote the settling of fine particulate matter (sedimentation) which results in the smothering and death of Kokanee eggs.

d) Lake drawdown has not been much of a problem, but whenever it does occur, the consequences to the entire shore-spawning population are severe.

Introduction of Mysis relicta. Mysis relicta, commonly referred to as opossum or mysis shrimp, was introduced into Okanagan Lake in 1966. These organisms were introduced in hopes of boosting the productivity of the lake, providing extra forage for game fish and enhancing the fisheries industry. Decisions for the introduction were based on several other North American and northern European lakes that observed increased productivity within a few years after the introduction of Mysis relicta. In the beginning , fish populations rose variably for the lakes, but then began to collapse. Scientists discovered that Mysis relicta is a good prey item for large Kokanee, but not for Kokanee aged less than one year. The shrimps are too large for small Kokanee to handle. The major food source for young Kokanee in Okanagan Lake is a small zoo plankton species called Daphnia, otherwise termed the "water flea." Unfortunately, Daphnia is also the preferred food item for Mysis relicta. This lead to competition for the same food source, but the shrimps are more efficient predators than the Kokanee. They feed during the night, whereas the Kokanee do not, and they have a rapid generation time. Mysis shrimps have few predators and normally inhabit different zones of the lake than the Kokanee. It is unknown if Mysis relicta populations have stabilized in Okanagan Lake. If they continue to rise, the Kokanee population will continue to drop.

5.2.3 Saving the Kokanee

One of the major projects in the Okanagan to help restore Kokanee populations is the Mission Creek Spawning Channel. The channel was developed to restore favorable conditions for Kokanee spawners. Clean gravel and special fencing was installed to direct Kokanee into the best spawning areas. It was hoped that these efforts would increase egg and fry survival rates from 5 % in the wild to 80 % in the channel. To date, the channel has not been as successful as hoped. In 1992, 36,000 Kokanee used the spawning channel, but by 1995 this number dropped to 5,000.

In addition to costly enhancement projects such as the one at Mission Creek, the Province of British Columbia imposed a ban on Kokanee fishing in Okanagan Lake in 1995. Scientists believe that this ban will be in effect to at least the year 2001. To avoid Kokanee over-fishing in nearby lakes, the province also reduced catch limits from 5 to 2 Kokanee per day on Wood and Kalamalka Lake.

5.3 Introduction of Knapweed

Two types of Knapweed, diffuse and spotted, are common throughout the Thompson-Okanagan.

5.3.1 Diffuse Knapweed ( Centaurea diffusa Lam)

Distribution. Diffuse Knapweed occurs over a wide range of ecological habitat types. It tends to dominate in dry valley bottoms in the Bunchgrass zone, in the transition areas of Ponderosa Pine zone and in the interior of the Douglas Fir biogeographic zone. It therefore occurs primarily in the Kootenays, Thompson-Nicola and Okanagan regions, the Kettle River Valley and the Fraser Canyon. Diffuse Knapweed is also present at a lower abundance in the Cariboo-Chilcotin. In the Okanagan, diffuse Knapweed is more dominant in the drier regions south of Kelowna.

Description. Diffuse Knapweed has a single upright stem 20-100 centimeters. (8-40 inches) tall and numerous spreading branches. Plants bolt in early May, usually producing one stem with numerous flower buds which bloom in July and August. It has white, sometimes pink or purple, urn shaped flowers surrounded by yellowish green bracts with narrow to short distinct, stiff spines. It is a biennial to short-lived perennial weed. Diffuse Knapweed spreads by seed dispersed with the movement of plant material. Under rangeland conditions, over 900 seeds per plant are formed while over 18,000 seeds may be produced under irrigation. This plant is contains volatile oils and is extremely bitter tasting but non-poisonous.

(A compound has been isolated in Russian knapweed that is cancer causing. This compound may also occur in spotted and diffuse knapweed. Please be careful not to injest knapweed or have its sap enter open cuts on the skin.)

5.3.2 Spotted Knapweed (Centaurea maculosa Lam)

Distribution. Spotted Knapweed is found throughout British Columbia. It is found primarily at lower to mid-elevations of the southern interior from the Nelson area through the Kootenay, Okanagan, Thompson-Nicola, and Cariboo- Chilcotin regions. It also occurs in isolated pockets elsewhere in the province. In the Okanagan, spotted Knapweed essentially grows in the moister areas of Vernon and Armstrong.

Description.Spotted Knapweed is a short-lived perennial weed that disperses mainly by seeds. Mature plants are 20-120 centimeters (8-48 inches) tall, with long fibrous tap roots. Overwintering rosettes bolt in early May to produce one to fifteen stems that are somewhat hairy when young (likewise are its young leaves) and highly branched. Thistle-like pink to purple flowers, 1-1.5 centimeters long bloom from July through to October. Bracts of the flower head are easily recognised having a black-tipped fringe, giving the flower head a spotted appearance. Each flower is capable of producing 400 seeds under rangeland conditions and over 25,000 seeds when irrigated. The plant contains volatile oils with a distinctive smell and has an extremely bitter, non-poisonous taste.

(A compound has been isolated in Russian knapweed that is cancer causing.This compound may also occur in spotted and diffuse knapweed. Please be careful not to injest knapweed or have its sap enter open cuts on the skin.)

5.3.3 Origin and Dispersal Mechanisms

Knapweed was introduced from Eurasia in the early 1900s. Since Knapweed has no naturally indigenous enemies or parasites in North America, it rapidly spread across the province. The Okanagan grasslands became infested with Knapweed during the 1940s and 1950s, and it has become well established during the last three decades.

Knapweed is easily distributed great distances by being caught up and transported in the under carriage or doors of recreational vehicles, trains, light air craft landing at infested airstrips, logging trucks, and heavy machinery. It is also spread by florists, who use Knapweed in dried floral arrangements. Hay-farmers moving from infested to non-infested sites can transport the weed along with them. Animals and birds may pick up the weed and disperse it. Some birds and small rodent species that eat Knapweed seed and then disperse it in their faeces. Wind can also disperse seeds and sever diffuse Knapweed at ground level when mature, to blow it around in a tumbleweed fashion.

5.3.4 Problems

Both Knapweed species are highly competitive and are capable of invading grassland sites and out competing all native vegetation. In addition, these sites supply domesticated animals with 80 % of their diet as grasses and herbs. Knapweed encroachment can also destroy the forage base resulting in significant declines in deer and elk populations.

Over 40,000 hectares (100,000 acres) in British Columbia are infested with Knapweed, reducing forage potential by up to 90 % in some areas. There is approximately 1 million hectares (2.7 million acres) of grassland range and undetermined areas of fringe forest in British Columbia which Knapweed can potentially infest. If spread to its ecological limit, Knapweed could infest up to 8-10 million hectares (20-26 million acres) in Western Canada. To date Knapweed has resulted in an economic loss of over $400,000 annually in equivalent hay production in British Columbia. If Knapweed spread to its limits, that figure could climb to over $13 million annually.

5.3.5 Control Methods

.Successful long-term control requires the combination of proper grazing management, judicious herbicide use, the development of effective biological control and a high level of public awareness and responsibility..Containment programs in British Columbia using herbicides are currently underway to protect non-infested grassland. In the Okanagan, Knapweed has been established for at least 30 years and cannot be eliminated using chemical herbicides. Biological controls include seed reducing flies ( Urophora affinis and Urophora quadrifasciata ) from Eurasia that are now well established throughout infested areas. These flies can reduce Knapweed seed production by 95 %. Further reduction in seed production has resulted from release of a moth ( Metznera paucipunctella ) against spotted Knapweed and a root feeding beetle ( Sphenoptera jugosslavica ) against diffuse Knapweed. In 1976, root feeding beetles were released near White Lake (just outside of Penticton) to control diffuse Knapweed. The populations etablished themselves and these beetles are now collected and transported to other Knapweed infested sites in British Columbia. There are several other insects, including other moths and beetles that can be used successfully to control Knapweed infestations. Research shows that insects used in combination is the best defence for controlling the spread of Knapweed.

5.4 Threatened and Endangered Species of the Thompson-Okanagan

5.4.1 Mammals

There are numerous mammal species in the Okanagan either classified as threatened or endangered. Some of these species cannot be found anywhere else in British Columbia and some cannot be found anywhere else in Canada.

a) Pallid Bat (Antrozous pallidus)

b) Spotted Bat (Euderma maculatum)

c) Badgers (Taxidia taxus)

d) Nuttail's Cottontail (Sylviagus nuttalli)

e) Western Harvest Mouse (Reithrodontonys megalotis)

f) White Tailed Jackrabbits (Lepus townsedii)

5.4.2 Birds

Bird populations in the Okanagan region are primarily effected by urbanization and agricultural practices. The riparian habitat, especially that along creeks that drain into the lakes or Okanagan River is a popular farming area and development site that affects the breeding habitat for many birds. Birds in the Thompson Okanagan region that are presently classified as threatened or endangered include:

a) Western Screech Owl (Otus kennicotti)

b) Lewis' Woodpeckers (Melanerpes lewis)

c) Burrowing Owl (Athene cunicularia)

d) Flammulated Owl (Otus flmmeolus)

e) Peregrine Falcons (Falco peregrinus anatum)

f) Grasshopper Sparrow (Ammodramus savannarum)

g) Prairie Falcon (Falco mexicanus)

h) Sage Thrasher (Oreoscoptes montanus)

i) Yellow Breasted Chat (Icteria virens)

5.4.3 Reptiles

The Thompson Okanagan area has the highest reptilian species density for British Columbia. Some biologists believe that the region south of Penticton is the most likely place for the discovery of a reptile species new to the province. Reptiles at risk in the Okanagan include:

a) Short-horned Lizard (Phrymosoma douglasii) :

b) Nightsnake (Hypsiglena torquata)

c) Short-Horned Lizard (Phrynosoma douglasii)

d) Western Rattlesnake (Crotalus viridis)

5.4.4 Amphibians

While amphibians are generally associated with damp, aquatic ecosystems there are some species that survive in the dry valley of the province's southern interior. Amphibian species suited to drier climates are known as habitat generalists (that is they have a substantial range in which they can move to and from a water source). Amphibians at risk in the Okanagan Valley are mainly of this type:

a) Great Basin Spadefoot Toad (Scaphiopus intermontanus)

b) Tiger Salamander (Ambystoma tigrinum)

5.4.5 Plants

The diversity of vegetation is reduced by the introduction of species, overgrazing and development. Grasslands provide habitat for a large number of species, many of which are now considered threatened or endangered. It is difficult to find any natural grasslands left in the Valley. Areas that are inaccessible to humans and livestock are the only ones that remain. Ponderosa pine and bunchgrass are also considered threatened while riparian areas and lakeshore forests are believed to be very threatened. In the South Okanagan alone, 67 plant species are considered rare, threatened or endangered.

5.4.6 Invertebrates

The invertebrates comprise of the largest component of British Columbia's biodiversity, but the least amount of information is known on this major biological group. It is virtually impossible to apply an actual status to the species due to a lack of information. Scientists believe that in British Columbia there are approximately 35,000 species of insects, but only about 15,000 have been discovered to date. This biological group is important in that their diversity is a good indicator of small, unique habitats. The problem for most of the threatened and endangered invertebrates is habitat destruction. Within the province there are roughly fifty species of insects that are on the endangered or threatened lists. It is important to note that invertebrates are not considered wildlife in the province of British Columbia and are consequently not included in the Wildlife Act's endangered species list. Some endangered or threatened insect species in the Thompson-Okanagan include:

a) Back Swimmer (Notonecta spinosa)

b) Ground Mantis (Litaneutria manor)

c) Tiger Beetle (Cicindela parowana)

d) Vivid Dancer (Argia vivida)

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