Mountain Pine Effects on Aquatic Ecosystem By David Bob NRTC 165 Fisheries Ecology Bob Davis April 7, 2006 Abstract When we think of the mountain pine beetle and what effects it will have, we generally think of only the effects that it will have on the terrestrial ecosystem. We must broaden our thinking to understand that this insect will have a dramatic impact on our aquatic ecosystem as well. The impacts on overstory and understory coverage will have an effect on hydrological systems. Over all, the water cycle and groundwater will be impacted by disturbances in forest environments and this in turn will have an effect on our climate. We have begun to understand that we can no longer eliminate the MPB, so we are turning our focus towards recognizing what the effects may be. The way in which we manage our ecosystems must, and will change in the future if we hope to preserve the vital systems within our planet. Table of Contents Abstract……………………………………………………………………………...i Table of Contents……………………………………………………………………ii List of Illustrations………………………………………………………………….iii 1. Introduction……………………………………………………………………….1 2. Practices…………………………………………………………………………..1 3. Understanding…………………………………………………………………….2 4. Harvesting………………………………………………………………………...2 4.1 Clear Cut………………………………………………………………………...3 4.2 Natural Evolution………………………………………………………………..4 4.2 Road Construction……………………………………………………………….4 5. Fire………………………………………………………………………………...5 5.1 Wildfire…………………………………………………………………………..6 5.2 Prescribed Fire……………………………………………………………….…..7 5.3 Soil…………………………………………………………………………….…8 5.4 Riparian………………………………………………………………………..…9 6. Riparian…………………………………………………………………………....9 6.1 Riparian Plants…………………………………………………………………...10 6.2 Soil…………………………………………………………………………….....11 6.2 Stream Banks………………………………………………………………….…11 7. Wind…………………………………………………………………………….…12 8. Invasive Species…………………………………………………………………...13 9. Conclusion…………………………………………………………………….…..13 Work Cited .15 Appendix A………………………………………………………………………….17 List of Illustrations Illustration 1…………………………………………………………………………5 Road Construction (2006) Illustration 2..…..........................................................................................................6 Ecological Rationale and Implementation (2006) Illustration 3…………………………………………………………………………7 Forests and Lands (2005) Table 1……………………………………………………………………………….8 Ecological Rationale and Implementation (2006) Mountain Pine Effects on Aquatic Ecosystem 1. Introduction We have now adapted to the understanding that we can no longer combat the Mountain Pine Beetle (MPB). As the MPB spreads over vast terrestrial ecosystem and the infected stands are removed, we must try to understand what the impacts will be. To mitigate the effects, we will have to make judgment calls at an unprecedented pace. Little study has been done in Canada in understanding our ecosystems let alone the effects of the MPB. Instead, we rely on studies from the US. Though these ecosystems are similar in many aspects, they do vary in design. As our knowledge changes every year, we will have to adapt our prescriptions towards dealing with the effects and outcomes of MPB. The control of the MPB has posed a very difficult challenge. This is due in part to the human made habitat and climate. Never before have we had such an unprecedented infestation of MPB in our province. The enormity of the current infestation was created by western practices. 2. Practices If we look back to past practices of silviculture, we can acknowledge where mistakes have been made. When we harvested our forests, we understood that lodgepole pine trees have greater value after production due to the fact that they have less limbs growing on them. This value was the equation we utilized to determine how we replanted our forests with dense stands throughout the province of BC. This in turn provided a vast feeding ground for MPB as the trees matured. We failed to acknowledge what effect this may have on this tiny insect. With global warming this has also changed the habitat of the MBP. General knowledge of the MPB has changed in the past couple of years and we are now challenged with understanding the effects that they will cause. 3. Understanding Western scientists had previously understood that the MPB infected only mature pine trees; we now know MPB infects younger trees as well (Ecosystem Restoration). We had once thought that MPB infected only lodge pole pine, we now know MPB infects all pine. We had once thought the rate of infestation was only 40 km/year, we now know MPB infects at the rate of 80 km/year. We once understood that the average infestation lasted only 8 years due to climate controls. We are now entering the sixth year of infestation, and the MPB shows only signs of increased infestation. Our climate is changing, and so will the impact of the MPB infestation. We are now moving away from attempting to eliminate the MPB; we are now focusing on harvesting the economic value of these trees before the value is lost. We not only have to focus on the economic but the real possibility of vast decaying forest stands due to the inability of harvesting infected trees fast enough. It is difficult to determine the best method to utilize in fighting MPB, but we do know we are faced with many challenges. The challenges we face will evolve to affect aquatic ecosystems. Even something as distant as harvesting will affect watersheds. 4. Harvesting The government has now moved away from sustainable harvest levels and we are currently harvesting faster then forests can regenerate so we can reclaim as much of the economic value of the infested wood before it deteriorates, and also to limit the impact of wildfires in the future (Rationale and Implementation). By harvesting we may also be able to slow the rate of MPB spread. Harvesting will occur on a scale unseen before and we must take action to limit the impact. In harvesting we must not fail to acknowledge what the effects will be to hydrology within the terrestrial ecosystem. 4.1 Clear Cut The harvesting of trees will have a dramatic impact to the amount of water within ecosystems, water retention and method in which the water table is affected. The harvesting of timber stands will have a direct influence on how snow melts in the spring (Climate Change). Snow disappears from grasslands two weeks prior to snow melt under a canopy. This will lead to earlier run-offs. This is due to the fact that grasslands absorb less solar radiation then forest canopy. As our grasslands become more predominant in the landscape, forest temperatures will be impacted. Wind will carry the warmer temperatures of the grasslands into the forest canopy, allowing for earlier snow melt. Forests also play a major part in interception. Interception adds to humidity within our forests. Entrapment of water slows the rate of evaporation. Trees and understory also play a major part in reducing the surface flow. If we lose forest cover we will have greater surface runoff. The roots of plants loosen the soil and allow more infiltration of water. Plant species also offer a method in which to slow the rate in which water is discharged. If we lose the plant cover we will then have less water retention for the summer months. Tree stands have deeper reaching roots then that of shrubs or grasses. The deep roots of trees allow for deeper infiltration of surface run off. The deeper roots also allow for a slower rate of percolation through the soil. The forest canopy absorbs more solar radiation then grasslands permitting cooler soil temperature. With cooler soil temperatures cooler water temperatures between the soil aggregates exist. Water will eventually percolate into our streams and help cool the stream channels. We may look to a more natural method in managing the lost forest stands. 4.2 Natural Evolution The David Suzuki foundation has presented strong arguments as to why we should not clear cut out forests. If we look at forests after a MPB attack, we see numerous standing dead trees. However, if we look at what lies under these trees, there is a thriving, healthy community of understory (Forests and Lands). This understory can lead to the natural succession. Even with the dead pine it can help the environment by decaying in a natural way adding more nutrients to soil over time. The trees, even when dead, offer shade that can reduce the temperature of the forest floor. If we can not manage such a complex ecosystem as a forest, we should then preserve as much of the natural ecosystem as we can. We must be protecting these ecosystems, keeping them intact as a means to learn, a means in which to learn how theses ecosystems can be so productive. We must be careful in taking into consideration all of the effects of harvesting. We must not fail to acknowledge that the rate and direction of percolation can be altered by road construction. 4.2 Road Construction The construction of roads will also have a dramatic impact on hydrology (Road Construction). Vast amounts of our forests currently do not have road access into the timber area. Construction of new access into this area will have to be done in a very careful, methodical method. Roads can intercept surface run-off and allow a change in drainage patterns. This interception can lead to water accumulating in areas that were previously drier. Culverts also have to be carefully constructed and monitored, in time; culverts will accumulate material which can block water flow. When we want to do a prescribed burn, we must ensure we have access to the area in case we may require additional support crew (Road Construction 2006). With MPB impact in such a large, undeveloped area, this can pose some challenges. Illustration 1 Road Construction (2006) Some parts of BC have better road systems than other areas. We will have to study the topography to ensure the least amount of impact is sustained in constructing roads. With the building of roads, we will have to use the least amount of area in construction. Roads will be essential in accessing the ecosystems for harvesting and prescribed fires and unprescribed fires. 5. Fire No matter how it occurs, fire will have a greater impact on our forests in the future (Ecological Rationale and Implementation). If we manage to utilize fire in an appropriate manner, it can be used to our benefit. In dealing with the Mountain Pine Beetle (MPB), the utilization of fire on terrestrial ecosystems can provide a means to preserve the terrestrial life in the ecosystem. We do have knowledge regarding the effects of wildfire. But we will have to enhance our knowledge to learn how to best conduct a prescribed fire. This study will have to be performed in a short amount of time as the forests are under attack and we have little time to idly sit by. We are fighting a losing battle with the MPB, one that will leave many casualties in our forests. We must either learn to reintroduce controlled fire into ecosystems, or nature will do this for us in an uncontrolled manner. Illustration 2 Ecological Rationale and Implementation (2006) 5.1 Wildfire If we look at the Yellowstone fire that occurred in 1988, we will have a better understanding (The 1988 Forest Fires…). A MPB outbreak occurred in Yellowstone 10 years prior to the fire occurring. There was very little addition to surface loading materials, but the standing timber that had been infested created the perfect stage for a candling fire. There was very little fire fighters could do in this instance to combat the fire. If we look at the southern part of BC and how fast we are harvesting the attacked trees we may wonder how this can possibly occur here. We must understand that the attack is also occurring in central BC where there is less population, thus less infrastructure in place to deal with the harvesting and processing on pine trees. This is where our greatest challenge will lie in the future. With over 40% of pine trees dead and un-harvested; the BC government will have to find a way to combat the effects of the loss of infected pine stands. Yellowstone is a prime example of where plant species regenerated naturally after a fast, low intensity fire proceeded through the area. The dead pine stands did not completely burn and eventually fell to add to surface fuel. This is a recipe for another fire to later proceed through the area once again as a high intensity fire that can destroy plant communities and soil aggregates. We must ensure this will not happen in BC so that our water cycle is not affected even more then it already has been. This can be done through prescribed burns. 5.2 Prescribed Fire To utilize prescribed fire, we must first understand that it has to be performed in a controlled manner, and understand why we want a fire. A prescribed fire must be performed to strike a balance between protecting the environment and maintaining social and economic stability. To protect an ecosystem, we must understand the effects of the impact and the properties within the ecosystem. A terrestrial ecosystem has an abundance of dead biomass, functional sensitivity, long lived species, and pollution sinks. Illustration 3 Forests and Lands (2005) With that in mind, we will have to take a close look at various aspects before we perform a prescribed fire. These factors are: • Number and arrangement of overstory trees by species • Number and arrangement of understory trees by species • Understory plant community • Quantity, decay class and arrangement of dead surface material • Size and severity of fire • Terrestrial habitat We will need careful planning to ensure the desired effect is achieved in a prescribed fire. The season, climate, topography and intensity of dead biomass will determine the intensity of flames. If the flames become too intense they can have a negative impact. Negative impacts can adversely affect the soil. 5.3 Soil Soil elements are lost at various temperatures of a fire. Soil Heat Level Impacts Soil Constituent or Property Temperature (Celsius) Carbon 100 Water 100 Hydrophobicity 175 Nitrogen 175 Organic Phosphorus 350 Sulfur 375 Clay Aggregate 500 Potassium 550 Inorganic Phosphorus 770 Sodium, Magnesium, Calcium >800 Table 1 Ecological Rationale and Implementation 2006 A temperature on the duff layer for only 1 minute will have an adverse effect on clay aggregates. Soil is an agent that is non-renewable and we must take great care in protecting it. Soil color, if darkened by fire, will attract more solar radiation, thus increasing the rate of evaporation. Slope can also play a key part in the degradation of soil. By attempting to retain some of the understory plants or trees we may prevent erosion from happening. Erosion can also occur by hydrological effects of precipitation. If we do not have sufficient plant coverage on soil, this will lead to reduced growing habitat for future plants. Plant coverage is even more essential in the riparian zone. 5.4 Riparian Besides the terrestrial ecosystem, we also have to take into consideration the riparian zones. The vegetation here can take longer in some instances to replenish. The vegetation here is very unique and of high importance. Riparian zone systems control the quality of our watersheds and the habitat within it. Of all areas to manage, this will be the most difficult as it creates a buffer between terrestrial and aquatic ecosystems. More planning is required for prescribed burns. 6. Riparian The riparian area will be the most difficult area to manage in a MPB attack. We have left a 50 meter buffer between the aquatic and terrestrial ecosystems, as this zone is very difficult to manage and regenerate. We could harvest this area, but harvesting creates vast amounts of devastation to understory vegetation. We could leave this area to regenerate naturally, but as seen in Colorado where the riparian area was left alone, fire eventually destroyed the dead overstory and thriving understory. This will be a challenging aspect to determine the best course of action. Perhaps the best method is a system of selective logging in riparian areas as well as a carefully monitored prescribed burn. The problem then falls into who will be responsible for the funding of such a program. The riparian does not fall into Department of Fisheries or Ministry of Forests mandate. The loss of the riparian zone, if unmanaged, will lead to redirection of rivers and streams. The overstory is essential for regulating water temperature and adding material into the water which permits greater insect life to form. Increased siltation of the water will also occur. This can then lead to greater water turbidity and loss of gravel beds for fish bearing streams. The degradation of riparian areas will affect plant life within this system. 6.1 Riparian Plants The riparian plants are essential for providing leaf mater which will fall and provide food for aquatic insects. This in turn provides food for fish that rely upon these insects for substance. In many situations, returning salmon then spawn and die. The decaying salmon carcasses along our stream banks will then provide food for the riparian plants. This exchange of food in the detritus chain is essential for maintaining a healthy ecosystem. Plants not only provide food for various species, but also allow for shade for the water ways. This shade is imperative to reducing water temperature. The shade of the overstory provides an area in which the fish may seek shelter from hot sunny afternoons. Many species of fish rely upon water temperatures to remain within a certain boundary. Even a couple of degrees in water temperature can have an ill effect on returning salmon spawning populations. Plants along our riparian area provide a means in which to stabilize the banks along river systems. The roots prevent erosion of the stream banks. If the banks were to erode, this would only lead to additional soil being added to the water. The erosion of river banks would only widen the course in which the river flows. A river that is not as deep will have a warmer temperature then that of a deeper river system. If water temperatures rise even along the small streams only one degree, this will increase the temperature of larger streams as it interfaces with the smaller steams along the way. This can then lead to a rise of a few degrees in water temperatures as we have seen in the Fraser River over the past few years. The constant rise of temperature along water ways will only place increased stress on returning salmon as they migrate to spawn. Soil is very important to maintaining a healthy plant community. 6.2 Soil Soil plays a vital part in the health of river systems. If we have too much loss of plant life along riparian area, we can then expect more soil to be added into the river. This addition of soil can lead to degradation of gravel beds that are vital for spawning beds of fish. If the returning salmon have less gravel beds in which to deposit their eggs, they will destroy the redds of other salmon. They will not try to find unused areas, only concentrating on ensuring they deposit the eggs in which they carry. Soil can also decrease the content of oxygen in water. With more siltation occurring, the fish species within the system will then have a difficult time in breathing. This can then lead to more mortality within the stream. This effect can be best noticed when there is degradation of stream banks. 6.3 Stream Banks The loss of banks along the riparian area will eventually lead to shallower, wider streams. A shallower stream will mean higher water temperatures. The deeper a water system is, the cooler the water. If the water system rises too high it will then have less oxygen particles. Less oxygen will lead to higher mortality of fish. It takes decades or even centuries to form the channels that streams follow now. These can slowly erode and instead of a slow winding stream we could end up with straight streams which produce faster flowing systems. The erosion rate of the stream banks will depend on the composition of the parent material, volume of water and turbidity of the system. In some instances we may have time to deal with the loss of plant life along the riparian area, but we must not forget it will also take time for plants to re-establish themselves once again. We may have to intervene with rehabitation or revitalization within this area. Wind can also play a part in the erosion factor of the riparian zone as well the temperature of our aquatic ecosystems. 7. Wind Wind already plays a role in the patterns of precipitation within our province. But if we look at the effects of wind on grasslands and forest canopy, we can better understand how this can influence water systems. It is known that a forest canopy absorbs more solar radiation then grasslands. This means that it is hotter in grasslands as the soil absorbs more heat from solar radiation than the plants. Since the composition of covering foliage determines the average heat within an ecosystem, this will have a dramatic impact as we move from what are now dense forest canopies into more open grasslands. The average temperature within BC will increase and these temperatures will be carried into forest and riparian ecosystems. Even though these areas can be distantly apart, this will mean increased soil temperatures within the soil. Once again the temperature of soil will increase, thus increasing the temperature of water within the soil. Once we consider all of the mentioned aspects we have yet one other point to factor in, invasive plant species. 8. Invasive species Combating invasive species is a challenging issue. Even without the future issues in dealing with MPB, we already have a problem in fighting invasive plants in our ecosystems (Invasive Species). Invasive plant species grow at an alarming rate and density. These species grow best on disturbed sites. With the vast wilderness impacted by MPB we must start to understand how to best limit their encroachment into ecosystems. Invasive plants, if left uncontrolled, will dramatically affect the ability of native plant species to thrive in their natural environment. The long roots of invasive plants and rate of reproduction will inhibit native plant regeneration. These plants also have deep long roots to gather water. This can lead to less plant foliage and regeneration of plants within ecosystems. This will only mean that we will face more challenges for aquatic ecosystems. 9. Conclusion No matter how we look at the MPB, we must change the way we think and start to plan for the future. We face numerous challenges ahead in dealing with the current and future impacts of this insect. Everyone will feel these impacts in the future, as the loss of our pine forests will have a dramatic effect on everything from terrestrial ecosystems to aquatic ecosystems. We must now understand where we went wrong and how we can best plan for the future. We must learn to adapt to the rate of spread and the impacts that the MPB is imposing upon us. With the reports coming out that this has been the warmest winter on record in BC; we will undoubtedly see the greatest rate of MPB infestation on record so far. There is so little we yet understand about or ecosystem. By working in conjunction with other communities and organizations we may gain a better insight that will allow us to adapt our practices to a means of better sustainability. We must work together, all agencies; to derive better practices for our ecosystem if we wish do maintain the diversity we have today. Work Cited Davis, Bob. (Classroom notes) 2005-2006. Dobson, Don (Engineer) Road Construction. (Power Point Presentation). Presented February 28, 2006, from FORREX Workshop, Thompson Rivers University. February 28, 2006. Environment Canada. Climate Change. Retrieved March 11, 2006, from: ec.gc.ca/climate/overview_canada-e.html. 2005. FORREX Workshop, (Open Dialogue). Thompson Rivers University. February 28, 2006. Gayton, Don (Ecologist) Ecosystem Restoration. (Power point presentation). Handouts from FORREX Workshop, Thompson Rivers University. February 28, 2006. Gray, Robert (Ecological Consultant) Ecological Rationale and Implementation (Power Point Presentation).Presented February 28, 2006, from FORREX Workshop, Thompson Rivers University. February 28, 2006. Jeffries, Liis. (classroom notes) 2005-2006 Polster, Dave (Environmentalist) Invasive Species. (Power Point Presentation). Presented February 28, 2006, from FORREX Workshop, Thompson Rivers University. February 28, 2006. Ruhf, Robert. The 1988 Forest Fires of Yellowstone National Park. Retrieved March 18, 2006 , from x98ruhf.net/yellowstone/fire.htm. 2006 Suzuki, David. Climate Change. Retrieved March 11, 2006, from: davidsuzuki.org/Climate_Change/. 2006 Suzuki, David. Forests and Lands. Retrieved March 11, 2006, from: davidsuzuki.org/Forests/Biodiversity/Climate_and_Biodiversity.asp. 2005. Wood, Christine (MOE) Ecosystem Restoration Strategy. (Power Point Presentation). Presented February 28, 2006, from Thompson Rivers University. February 28, 2006. Appendix A Bob, David. Edge Effect, (Field Lab) March 23, 2006.
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