Saltwater and Spruce Trees

June 17, 2016

A rumor came my way last week that is so off base I am writing about it today. 


On Highway 101 in south Pacific County, there is a straight stretch of road from Bear River to Greenhead Slough. Last year, a bridge replaced a very undersized culvert near the north end of the straights. That summer, trees began dying along the highway, upriver from the new bridge. 

June 2016:  Sitka spruce and Pacific crabapple trees are dead and dying along the road south of the new bridge; which is immediately to the left of this image. The road in the foreground is Highway 101; Bear River is to the right, looking south east along the highway.  

The rumor is that this area was sprayed with herbicide as part of industrial forest management. 

Marshes are not industrial forests; this low forest and marsh area is part of the Willapa National Wildlife Refuge. Corporate timber growers do not waste money spraying non-logging areas, especially on land they do not own. 

So if this area wasn't sprayed, what happened?

When the drainage was opened with a bridge in 2015, the upper reaches of the marsh east of the highway returned to the old hydrology pattern––fully tidal––which means that tide waters are higher at high tide than they have been for six or seven decades. Water levels are also lower at low tide. 

Fish, including salmon, can now easily enter the ditch along the highway, and from there, five or six streams that drain from the hills to the east. Floods no longer surge up to the road edge on the east side, held back by a small culvert and tide gate. Given that we have experienced more flash floods in recent years than in decades before, this is good. 

Trees, especially conifers that grew behind the tide gate, were abruptly exposed to saltwater on very high tides, and their roots began to die as soon as this salt exposure started. Sitka spruce, Picea sitchensis, is the dominant large conifer tree along the edge of Willapa Bay. A small hardwood tree, Pacific crabapple, Malus fusca, is also common in the marsh [the small gray bubbles in the background of the photo are crabapples].  Both trees grow on slightly higher ground than the main marsh level. 

Summer 2016 is the second growing season with full tidal cycling, and the trees are now dead or dying along almost a mile of road. A few spruces are still green; these are trees that are slightly higher in growing position than those that are dead. 

Both species tolerate some salt exposure. The new hydrology brought too much salt to their roots, however. Six months of dry weather last summer probably accelerated the impact. The result was that several dozen conifers and even more crabapples abruptly died. 

If you look east across the marsh into the hills, you will see that trees on the slopes and at the base or toe of slope above the marsh are alive, still green and in active growth. Only the trees that were too low have died. 

There is another place to see the same sort of response to a change in hydrology, also on Highway 101 in south Pacific County, on Chinook River. Here the tide gate is closed only on extreme high tides, and the rest of the time, the gates are open so that fish can move more easily in and out of the river. 

Just east of the highway, there was a stand of alder; now it's a stand of snags with salt marsh sedges and other species covering the ground. This transition took just a few years with new gate management methods. The spruces behind the alders were high enough in position to keep living.  

Better management of water through changes in tide gates, or replacing gates with bridges means that fish can access their natal streams more easily. It also means that during periods of high rainfall more water drains off more quickly. These are good outcomes. But for trees that began growing in locations that were not quite high enough, it means that they can no longer live in those locations, and it's that abrupt change from alive to dead that catches our eyes as we drive Highway 101. 

Fawn Lily Seeds

Every spring and summer, bulbs set seeds. This sounds utterly trivial. It's what plants do. Yet it is something more––a recurring miracle of climate, soil, and all the hazards that can befall a plant on the way from bulb to flower to seed pod. 

Fawn lilies, genus Erythronium, are a bulb group that I have admired for decades when hiking in natural areas, and for the past 15 years or so, have also grown in my own garden. I have collected wild seeds on occasion, and often buy seeds from seed collectors. These seeds start in pots, where I can keep watch on them, head off potential problems, and shepherd them towards flowering size. 

In 2010 I participated in the North America Rock Garden Society's seed sale. NARGS offers some bulbs every year. That year one offering was labeled "Erythronium x pink". The seeds that came were of two sizes, and I should have taken the time to sort them out and plant them separately. But I did not. Instead the seeds were planted in a pot, labeled, and then time passed. 

Mixed pot of Erythronium bulbs in flower

In 2014 the first bulbs flowered. By this spring, almost all flowered, which was when I found that yes, these are all pink-flowered Erythroniums. But they are not all the same. Some have the mottled leaves of E. revolutum. Others have plain green leaves, more like garden hybrids of E. revolutum and other western species. 

This week I collected seeds from both groups, and this time, I kept the seeds separate. Yes, there are two different sources, two different sizes to these seeds. These two lots will go in separate pots when I plant them. 

Erythronium revolutum type seeds on the left, Erythronium x pink on the right. The grid is 5 mm.

Columbia Plume: Biologically unique yet often out of sight

Kathleen Sayce

August 2015

Visitors to North Head Lighthouse and the Lewis & Clark Visitors Center in Cape D State Park often notice the sweep of other-colored freshwater that wraps around Cape D and north along the beaches before spreading west and merging into the waters of the Pacific Ocean. They and boaters off the Columbia Entrance see 'rip lines' in the water, along which fishing boats drive, hoping to catch salmon. There may be several species of seabirds, sealions, seals, and whales all feeding along the rips.

This is the Columbia Plume, a massive flow of freshwater that slowly merges with saltwater off our coast. It brings nutrients, sediments, and yes, garbage and pollutants, to local ocean waters. The Columbia River is so large that the mixing zone, where fresh and salt waters merge, occurs mostly offshore, not in the river itself. Mixing takes place over many days and thousands of square miles.

Columbia River water retains a distinct chemistry, and has been tracked offshore in the open ocean south to California and north off British Columbia. The productivity of the Plume results from two large nutrient sources coming together in one place. Upwelled water from the deep ocean meets Columbia water, and the result is a very large increase in productivity. 

 We take it for granted, living here, and fishing for seafood.

Where there are nutrients in salt water, there are phytoplankton, and zooplankton, and the animals that feed on them, and those that feed on those animals, all the way to humans fishing for salmon. Northern Herring spawn in the plume. Their young feed on plankton so the Plume is an optimal place for them to spawn. 

Photo by Dr. Jen Zamon, of Sooty Shearwaters in a mega-flock in the Columbia Plume.

Many fish, including salmon, seals, porpoises, and pelagic birds feed on these species. When Northern Herring school to feed, predators follow. On some days, even from shore, you can see hundreds of thousands to millions of birds feeding from the skies, often more than twenty species, swirling in huge masses above the fish schools in one great mega-flock.

Beneath the surface, and so out of sight, are fish and marine mammals, also feeding on herring. Mega-flocks form up regularly when herring group into large schools. They are common only in a few areas along the Pacific Northwest coast, and the Columbia Plume is one of the main areas where mega-flocks occur. Cormorants, loons, grebes, fulmars, gulls, murres and alcids participate in mega-flocks.

Other bait fish can also trigger mega-flock formation. These include Northern Anchovy and Pacific Sardine.

Where there are salmon, seal and porpoise, top predators show up, including sharks and Killer Whales. Killer Whales are regular visitors during early to late spring in the Columbia Plume. Gray Whales migrate north during spring; Killer Whales target the young calves. While some sharks are seasonal, many are here year round, and they also cruise the Plume for prey.

I met Dr. Jen Zamon of the NOAA Hammond Research Laboratory in winter 2015 to learn more about the Columbia Plume and mega-flocks of pelagic birds. One of my questions was where the large herring schools/mega-flocks occurred most often. Based on her research and others, mega-flocks occur anywhere over the continental shelf from the south end of the Olympic Peninsula to south of Tillamook Head. More than half the time, they are within 15 miles of shore. 

Photo by Dr. Jen Zamon of a mega-flock of pelagic birds feeding on bait fish north of North Head off Seaview, Washington. This flock was composed of several million birds of 20 species.

Occasionally they are very close in, and this is when we can view them from land. I saw a mega-flock for the first time in Spring 2014, from the South Jetty viewing platform––it had around 400,000 birds. Flocks of more than one million birds are common. Jen saw a mega-flock off Beard's Hollow, easily visible from land. They also form inside Willapa Bay and Grays Harbor when large schools of bait fish enter the estuaries.

We live in ecologically uncertain times, so every time a mega-flock forms, it's reassuring to know that something this spectacular and prolific is still able to happen. Like icebergs, we see just the above-water portion. In the water and out of sight are hundreds of thousands of other predators, feeding on herring and other bait fishes. And other predators, feeding on them. 

Stationarity Is Dead

By Kathleen Sayce

When civil engineers, architects and planners design buildings, roads, bridges, levees, dams, drainage canals and other structures, they use the principle of stationarity to decide how high, how strong, how wind resistant, this structure has to be to withstand a typical 50-year, 100-year, 500-year or 1000-year event.

All construction balances on a line between built 'strong enough' and 'over-built too much' to keep the cost as low as possible. The stationarity principle has historically ensured that the structure will last for its planned life, which may be anywhere from twenty years to several hundred years.

To settle on the event standards to design to, professionals refer back to applicable weather metrics and disaster occurrence histories, including high and low temperatures, rainfall, stream flows, floods, snow falls, wind storms, tornadoes, droughts, and earthquakes.

A recent rain burst in the west Willapa Hills overloaded a culvert on Peter's Creek that runs under Highway 4 near Naselle. In the background you can see flagging on the washout edges; the highway pavement is at the very top of the image. Photo by Kathleen Sayce.

One of the reasons modern cultures measure weather events is to provide metrics for infrastructure and building designers, planners and insurance agents. Building codes also emerged, to set minimum standards that ensure a building will not flood, catch fire or blow down during normal events, and will stay in good condition for its design life.

Several years ago a national science magazine ran an editorial which stated that the concept of stationarity was dead [I did not think of this title, I borrowed it from that article]. The authors are engineers, who explained that when a river community had three thousand-year flood events in five years, it was time to redefine a one-thousand-year event. That it was past time to reevaluate appropriate event standards with a new, broader measure of caution. Five percent (higher, wider, stronger) might not be enough anymore. Twenty-five percent might be better, or in some instances, fifty percent. [1 February 2008, P.D.C Milly et al, access via http://www.sciencemag.org/content/319/5863/573.short]

This washout on Peter's Creek occurred when blockage in the culvert due to debris coincided with a rain burst. Water built up behind the highway levee and pushed through, washing out the soil and road surface above the old culvert. Photo by Kathleen Sayce. 

Change goes on around us all the time, both in our culture and in the natural world. In the past three decades, local air temperature measurements changed. Plant growing zones are defined by winter low temperatures, and have been shifting steadily warmer for many locations. Fifty years ago, the South Coast of Washington was defined as a region 7 growing area, with winter low temperatures between 0 and 10° F. Today this same geographic area is considered zone 8, with lows between 10 and 20 °F. Similar changes have happened for many areas.

Along with warming winter temperatures, we’ve seen higher summer temperatures. In 2012, in just one hot spell, over one thousand high temperature records were broken in the Midwest. Many locations set new records day after day, until the heat wave finally quit. New records for consecutive days over 100 °F were also set.

If you are an engineer working on cooling systems, you have to design for increased cooling capacity. Otherwise, the cooling system will never work properly. Ditto on insulation and heating standards, stormwater, and roof snow loads.

The Astoria-Megler Bridge was designed in the 1960s. At the time, the design standards based on then-current stationarity guidelines looked pretty good. But now, knowing about local earthquakes and tsunamis, with ships four to five times larger and ten times heavier, with longer, heavier commercial trucks, and heavier passenger vehicles, the bridge is woefully under-designed. A new bridge in this location today would be designed to a new standard.

No one thinks this bridge is in eminent danger of collapse––that is not the point. The point is that data about traffic loads, weather extremes, wind loading, and seismic events has changed. The degree of uncertainty about event severity that can be expected has also changed. Stationarity has changed.

For a house, this means more insulation, stronger framing, a tougher roof, a higher foundation or a location on higher ground. For a road crossing a river, it may mean a larger culvert or stronger, higher bridge, along with higher road levels and deeper ditches to each side. For a stormwater system, it means more capacity.

Last winter, a rain burst in the west Willapa Hills flooded South Bend, overloaded culverts that drained west to the bay from there south to Naselle, and blew out a culvert on Peter's Creek in Naselle, taking out a section of Highway 4. Part of the flooding was due to blockages in culverts, and part to culverts that were faced with water flows well beyond their design capacity.

The new box culvert on Peter's Creek will look much like this one––a box culvert under Highway 101 that drains Chinook Marsh to Baker's Bay. This is a small bridge, and the new one is being designed now. Note where the dirty concrete begins; this is how high the water gets in this culvert on a regular basis. Photo by Kathleen Sayce

The culvert that formerly ran under Highway 4 will be replaced with an open box culvert, which means that there will now be a small bridge where there once was a corrugated pipe. Engineers are designing it now. In South Bend, storm drains were cleaned out, and their capacity will probably be reviewed.

A change in stationarity means, when constructing anything––a road, a culvert or bridge, a home, or other structures––it's time to let go of thinking that we know what might happen based on the past, and design instead for the next increment stronger, windier, colder, hotter, wetter, to be appropriate for that structure and location. The problem with our time is that the weather is not what it used to be, and our old stationarity standards need to be reset.

Ocean Acidification on the South Coast: Nature at Bat

March 23, 2015, ran in early April, 2015

Understanding ocean acidification is not simple, because the process of acidification is not simple. Neither is the rest of nature simple. Nature is more complex that we can imagine. We can over-harvest, mine, bomb, poison, pave and otherwise mess up this great world, do our very best to destroy the ecology that supports our lives, and yet, nature bats last.

There’s some predictability: If we pump greenhouse-warming gases into the atmosphere, the atmosphere will warm up. We are doing this. It is warming. Those gases are absorbed by water all over the world, because the balance of gases in the atmosphere is reflected by the balance of absorbed gases in the water. It’s a slow process, because there is a lot of water, which can hold a lot of carbonic acid and heat. That slow time lag between absorption and response has tricked many into thinking that what we do doesn’t matter to the global ecology.

Then there are down-welling and up-welling areas. There are areas of the oceans where cold salty water accumulates and drops down into the depths. Called ‘down-welling’ areas, these occur in the north Pacific, north Atlantic, south Indian Ocean and around Antarctica. Bottom flowing currents move the cold, salty water across the seafloor towards continents, where this water rises to the surface, called ‘upwellings’. There are upwelling areas all around the world. Some run all the time, others only with winds from certain directions. In the Pacific Northwest, upwelling usually occurs when winds are from the northwest in sunny, dry weather.

Upwelling in action:  Fog forms over cold water, comes ashore over the beaches, and dissipates over warmer land. On the horizon, blue water indicates the water there is warmer, not upwelled. This aerial is looking north over Ft Stevens across the Columbia Entrance to Cape Disappointment.  Photo by Kathleen Sayce

A summer day with active upwelling here on the South Coast is foggy with northwest winds. It’s sunny inland, it might even be sunny on Willapa Bay, but on the ocean beach it’s foggy. The fog is created when cold, old, very salty ocean water comes to the surface and cools the air. Onshore winds push the cold air onshore one, two, five, ten or twenty miles.

In the water, something more complex is going on when the acidic upwelled water reaches the surface. This water is typically thirty to fifty years old, and can be much older. It’s very salty. It’s high in some nutrients, and low in oxygen. As upwelled water rises to the surface, nutrients are taken up by phytoplankton that live only as deep as sunlight can penetrate into the water––usually less than fifty feet. Phytoplankton grow quickly in summer, tiny single-celled plants that can divide several times a day under good conditions. Those old nutrients are food for the phytoplankton.

Zooplankton can’t keep pace with the growth of plants. Not all phytoplankton cells are eaten, and when the excess cells die, they fall to the seafloor and decompose. This strips oxygen from the water column and seafloor, killing those animals that need oxygen to survive. Their bodies also decompose. More oxygen is tied up in each new wave of decomposition, forming a dead zone of low to no oxygen that expands as summer progresses.

A large dead zones appears each summer along the Pacific Northwest Coast; this year it persisted through winter. It typically extends from south Vancouver Island to northern California. Affected animals include crab, clams, fish, zooplankton, and more. Some fungi and bacteria thrive in low oxygen conditions, and they flourish in this dead zone, growing into huge carpets of mixed species––all thriving on no oxygen and high nutrients.

The second complexity is that this water is more acidic than it was a few hundred or even a few thousand years ago. Remember, what goes into the atmosphere is absorbed into water. With increasing amounts of carbon dioxide in the atmosphere, then in the water there is more and more carbonic acid, increasing the acidity of seawater.

The third complexity is that this cold, old upwelled water is low in calcium, and the local rivers are also low in calcium. For mollusks, calcium is essential to form shells. It also goes into solution (dissolves) easily in more acidic water, and as we have learned in the past ten years, more acidic water is not good for oysters and other bivalve larvae.

There’s always a weak point, a stage in a life cycle when each organism is most vulnerable to what appear to be tiny insignificant changes. For shellfish, this is as larvae, as they undertake the change from the free-swimming form to the shelled form, prior to settling down to become adults. At this stage, oysters and other bivalves grow their proto-shells. But in more and more acidic water, larvae can’t maintain shells, because the calcium dissolves out as fast as shell forms. The larvae linger for days to weeks, trying to make the change. Eventually they die.

But wait, you say, isn’t there deep, cold, low acid water off Hawaii? Hasn’t at least one oyster grower got a hatchery there, safe from the upwelled water? Yes. But oysters are not dominant species of food webs in the oceans of the world. Coccolithophores are a key animal, tiny calcium-shelled zooplankton that eat phytoplankton, and in turn are eaten by larger zooplankton and fish, which are eaten by larger fish, and on up the food web. Take coccolithophores out, and oceanic food webs aren’t just on a diet, they collapse. Fish populations go down; larger fish, birds and mammals that live on them are impacted too. Fishing fleets. Tribes. Food processors. Sport fishers. Oceanside restaurants selling fish and chips. Anyone who eats, catches, processes, and sells saltwater fish is affected.

So there you have it, a quick look at the complexity of ocean water chemistry, and the complexity of the ocean food web, and a hint at the coming changes in ocean ecology. There’s nature, standing near the plate, swinging the bat to warm up. She’s thinking about what she’ll do this time. She might bunt, and take out some nearshore ecosystems in a few key areas. Leave some other spots alone. Or swing for the fence, and crash major cocolith’ populations, along with sardines, anchovy and herring. If that happens, tuna, salmon, and other major fish populations go too, as these fishes are their key food sources. We simply don’t know what nature’s going to do in response to our plays, this time, or next time. We will have all the innings we can manage to stay in the game, but nature bats last. 

Considering Mosquitos

February 22, 2015                                                                                                           Kathleen Sayce

Insects are by far the largest of animal groups on the planet, with a staggering diversity of life forms and life styles. We tend to reserve a special loathing for insects that feed on blood, and mosquitos are probably at the top of that list, perhaps because they descend on their prey in clouds, or bite sleeping bodies, making a distinctive high-pitched sound that involuntarily triggers a faster heart beat and higher blood pressure.

That feeding cloud of mosquitos is composed of females, sometimes with males hanging around the edges. Successful feeders will depart with a full stomach of blood, take a day to digest it, then within a few more days lay eggs in suitable wet habitats. A week later, they repeat the cycle. The blood provides proteins to make the eggs, which mosquitoes cannot get from their other food source, flower nectar. In many species, females live five or six months, and overwinter in a sort of dormancy. The blood-borne diseases are picked up by females as they feed on infected hosts, and then spread to those hosts that they later feed on. The most dangerous mosquito, most likely to carry a disease, is the older female who has lived a few months and fed many times on a variety of animals and humans in areas where suitable diseases are found.

When not foraging for a meal of blood, both males and females behave more like flies––which mosquitos are close relatives to, the word 'mosquito' means “little fly”––congregating in their preferred habitats, drinking nectar for food, and hanging out. Where do they hang? It depends on the species. We have more than forty species of mosquitos in the state, and fourteen species in Pacific County. Some like salt marshes, and others freshwater marshes. Some like ponds with dense vegetation on the edges, others seek clean open water. Some like water-filled holes in trees. Others prefer manure-rich standing water, including sewage ponds and cattle yards. Still others seek out tiny containers, gutters, water in tires, or water-filled hoofprints in mud. Some look for sunny water sources, others for shade. Many live in lowland areas, but some prefer higher elevations, living in snowmelt ponds. As for time of day, that also varies. Some fly at dawn and dusk, others after dark, others in full daylight, some only in shade.

As for blood sources, all mosquitos do not prefer the same choices. Some only feed on amphibian or reptile blood––in our area, this includes salamanders and frogs, garter snakes and the occasional lizard. Others prefer bird blood. Many prefer large mammals, and those are the ones that we interact with most often. Some are generalists, mixing up meals between elk, deer, horses, cattle and people. Those that feed most often on large mammals and move between species are more likely to carry diseases.

In the 19^th century, malaria was endemic in the Pacific Northwest. Anopheles mosquitoes carry malaria, and were already here, disease-free, when humans carrying malaria arrived as settlers; and so for some decades, malaria was a chronic disease east of the Coast Range from Olympia south to the bottom of the Willamette Valley. This shows a typical pattern of disease transmission: Infected animals or humans enter a previously disease-free area, and mosquitos that carry that disease are already present, and begin moving the disease to new hosts.

The list of mosquito-carried diseases that have been found in North America is impressive: Western and Eastern Equine Encephalitis (WEE, EEE), St Louis Encephalitis (SLE), Japanese B Encephalitis (JBE), California Encephalitis (CE), Venezuelan Encephalitis (VE), West Nile Virus (WNV), Dengue virus, Malaria, Avian Malaria, Yellow Fever. There are also several localized diseases of specific areas. The actual disease organism may be a virus or protozoan; Plasmodium species, which are protozoans, are often disease-causing organisms, including multiple forms of malaria.

While many have railed that mosquitos fill no useful purpose, the fact is, they are here. Widespread use of DDT in the 20^th century demonstrated that attempting to wipe out mosquito populations with chemicals has disastrous unintended consequences on local ecosystems. Reducing their numbers, rather than waging all out war, is a better strategy.

First, know which species live in your community. It's very likely that there are several species, not one. Know the species, and you will know the larval habitat that species prefers. This is very important––without knowing what species you have, you may well spend your time and money in the wrong activities in the wrong places. Communities with mosquito control programs have staff that spend their time collecting larval and adult mosquitos and identifying which species live where; once they know the species, then they can work on the next step, below.

Second, reduce available larval habitat, or improve predation on larvae in those habitats. This is a good strategy for salt and freshwater pond and marsh mosquitos. Reduce and eliminate small sources of water too. These include old tires, bird baths, buckets and toys filled with water, gutters with standing water. Mosquitos can go from freshly laid eggs to adults in less than a week, so if you have bird baths, change the water at least twice a week. In ponds and ditches, Bti, a bacterial disease that kills larvae, helps with some species. Gambusia, a tiny guppy, eats mosquito larvae in freshwater ponds and lakes. There are other strategies too, these are just starting points to reduce larvae numbers.

Third, protect your home so that mosquitoes do not live indoors with you. Screened doors and windows are the first line of defense. Some species like to live around and in buildings. Keep your screens in good shape, and they will help keep mosquitos out of homes. Bed nets are also good, especially where night flying, malaria-carrying species are common. Currently this is not a local problem, but is very important where Anopheles mosquitoes and Plasmodium malarial species both live.

Fourth, cover your skin when outside. Mosquito hats (hats with fine netting from the brim to the shoulders), long sleeves, long pants, and good repellants all help. One summer Frank and I measured shore pine trees at Leadbetter Point in late June. Local populations of a native freshwater marsh mosquito were at their annual peak. We wore mesh hats, long sleeves and pants, used DEET repellant. Frank cored trees; I counted cores. The mosquito clouds were so dense that it was difficult to see the growth rings to count them, or my notes as I wrote down figures. We had to reapply DEET every 30 minutes to our hands, because after 25 minutes, the mosquitoes stopped hovering an inch or two above the skin, and started landing to feed. About day three, preparing for that day's work took sheer nerve!

As the weather warms up, after this unseasonably warm winter, expect hungry female mosquitoes to fly soon, and be ready for a long mosquito season.

Considering mosquitos

February 22, 2015

Insects are by far the largest of animal groups on the planet, with a staggering diversity of life forms and life styles. We tend to reserve a special loathing for insects that feed on blood, and mosquitos are probably at the top of that list, perhaps because they descend on their prey in clouds, or bite sleeping bodies, making a distinctive high-pitched sound that involuntarily triggers a faster heart beat and higher blood pressure.

That feeding cloud of mosquitos is composed of females, sometimes with males hanging around the edges. Successful feeders will depart with a full stomach of blood, take a day to digest it, then within a few more days lay eggs in suitable wet habitats. A week later, they repeat the cycle. The blood provides proteins to make the eggs, which mosquitoes cannot get from their other food source, flower nectar. In many species, females live five or six months, and overwinter in a sort of dormancy. The blood-borne diseases are picked up by females as they feed on infected hosts, and then spread to those hosts that they later feed on. The most dangerous mosquito, most likely to carry a disease, is the older female who has lived a few months and fed many times on a variety of animals and humans in areas where suitable diseases are found.

When not foraging for a meal of blood, both males and females behave more like flies––which mosquitos are close relatives to, the word 'mosquito' means “little fly”––congregating in their preferred habitats, drinking nectar for food, and hanging out. Where do they hang? It depends on the species. We have more than forty species of mosquitos in the state, and fourteen species in Pacific County. Some like salt marshes, and others freshwater marshes. Some like ponds with dense vegetation on the edges, others seek clean open water. Some like water-filled holes in trees. Others prefer manure-rich standing water, including sewage ponds and cattle yards. Still others seek out tiny containers, gutters, water in tires, or water-filled hoofprints in mud. Some look for sunny water sources, others for shade. Many live in lowland areas, but some prefer higher elevations, living in snowmelt ponds. As for time of day, that also varies. Some fly at dawn and dusk, others after dark, others in full daylight, some only in shade.

As for blood sources, all mosquitos do not prefer the same choices. Some only feed on amphibian or reptile blood––in our area, this includes salamanders and frogs, garter snakes and the occasional lizard. Others prefer bird blood. Many prefer large mammals, and those are the ones that we interact with most often. Some are generalists, mixing up meals between elk, deer, horses, cattle and people. Those that feed most often on large mammals and move between species are more likely to carry diseases.

In the 19^th century, malaria was endemic in the Pacific Northwest. Anopheles mosquitoes carry malaria, and were already here, disease-free, when humans carrying malaria arrived as settlers; and so for some decades, malaria was a chronic disease east of the Coast Range from Olympia south to the bottom of the Willamette Valley. This shows a typical pattern of disease transmission: Infected animals or humans enter a previously disease-free area, and mosquitos that carry that disease are already present, and begin moving the disease to new hosts.

The list of mosquito-carried diseases that have been found in North America is impressive: Western and Eastern Equine Encephalitis (WEE, EEE), St Louis Encephalitis (SLE), Japanese B Encephalitis (JBE), California Encephalitis (CE), Venezuelan Encephalitis (VE), West Nile Virus (WNV), Dengue virus, Malaria, Avian Malaria, Yellow Fever. There are also several localized diseases of specific areas. The actual disease organism may be a virus or protozoan; Plasmodium species, which are protozoans, are often disease-causing organisms, including multiple forms of malaria.

While many have railed that mosquitos fill no useful purpose, the fact is, they are here. Widespread use of DDT in the 20^th century demonstrated that attempting to wipe out mosquito populations with chemicals has disastrous unintended consequences on local ecosystems. Reducing their numbers, rather than waging all out war, is a better strategy.

First, know which species live in your community. It's very likely that there are several species, not one. Know the species, and you will know the larval habitat that species prefers. This is very important––without knowing what species you have, you may well spend your time and money in the wrong activities in the wrong places. Communities with mosquito control programs have staff that spend their time collecting larval and adult mosquitos and identifying which species live where; once they know the species, then they can work on the next step, below.

Second, reduce available larval habitat, or improve predation on larvae in those habitats. This is a good strategy for salt and freshwater pond and marsh mosquitos. Reduce and eliminate small sources of water too. These include old tires, bird baths, buckets and toys filled with water, gutters with standing water. Mosquitos can go from freshly laid eggs to adults in less than a week, so if you have bird baths, change the water at least twice a week. In ponds and ditches, Bti, a bacterial disease that kills larvae, helps with some species. Gambusia, a tiny guppy, eats mosquito larvae in freshwater ponds and lakes. There are other strategies too, these are just starting points to reduce larvae numbers.

Third, protect your home so that mosquitoes do not live indoors with you. Screened doors and windows are the first line of defense. Some species like to live around and in buildings. Keep your screens in good shape, and they will help keep mosquitos out of homes. Bed nets are also good, especially where night flying, malaria-carrying species are common. Currently this is not a local problem, but is very important where Anopheles mosquitoes and Plasmodium malarial species both live.

Fourth, cover your skin when outside. Mosquito hats (hats with fine netting from the brim to the shoulders), long sleeves, long pants, and good repellants all help. One summer Frank and I measured shore pine trees at Leadbetter Point in late June. Local populations of a native freshwater marsh mosquito were at their annual peak. We wore mesh hats, long sleeves and pants, used DEET repellant. Frank cored trees; I counted cores. The mosquito clouds were so dense that it was difficult to see the growth rings to count them, or my notes as I wrote down figures. We had to reapply DEET every 30 minutes to our hands, because after 25 minutes, the mosquitoes stopped hovering an inch or two above the skin, and started landing to feed. About day three, preparing for that day's work took sheer nerve!

As the weather warms up, after this unseasonably warm winter, expect hungry female mosquitoes to fly soon, and be ready for a long mosquito season.