Why care about native freshwater fish?

Reblogged from https://californiawaterblog.com

By Jason Baumsteiger

Even with a strong El Niño year, there are no assurances the drought is over. Clearly we need a better plan for future droughts and that plan needs to include provisions for native freshwater fish.  But why include native fish?

Source: Why care about native freshwater fish?


RiVR: Reference data for riparian forests


Since I haven’t yet published my thesis, this post is where it will live for those curious about the reference method I developed as the project for my Master of Forestry.

I’ve always been fascinated by the spatial structure of natural forests. I grew interested in reference information while at Urban Creeks Council. I wondered why the planting palette for every restoration project looked the same, and whether that was reflected out there in the undisturbed ecosystems we were attempting to emulate. Other types of reference information, particularly geomorphic data, is used in every stream restoration project, so why didn’t we have quantitative data for the ecosystems we were attempting to restore? No one had ever looked at that type of data before. As it turned out, the reference systems I studied bore very little resemblance to the restoration projects we were building.

RiVR, as I named it- the Riparian Vegetation Reference index- quantifies the species assemblages in riparian forests. It’s so specific, in fact, that it can tell us the exact number of species and individuals that we should be aiming for in restoration. While other reference programs like CRAM and SWAMP can give us (in CRAM’s case) general vegetation data and a site score, and (in SWAMP’s case) aquatic data by which the measure the effectiveness of restoration work, RiVR tells us exactly which species should be used on a restoration site and how numerous they should be.

One of the most important discoveries that came out of the project was the concept of relative species abundance- that is, how numerous the species on a given site are in relation to one another. This is a basic biological concept, but it had never been applied to riparian ecosystems before. My data indicate that there are typically three to four dominant species in a given assemblage (e.g., on a typical 100-meter site) and all other species- eighty-two percent of all the species I detected in all of my reference sites- were actually quite rare on their sites. I call these minor species. As rare as these species were on their reference sites, their universal prevalence on these sites suggest their critical importance to their ecosystems.


So, in contrast to the “plant only what survives” approach used by many restorationists, we can’t in good conscience call what we are doing restoration if we’re not restoring 82 percent of the species found in our reference system. And I only studied woody species, so imagine what the diversity would look like if

So the takeaways are, essentially:

  • Riparian forests have specific structural attributes that can be measured and replicated.
  • Relative abundance is an important component of these systems.
  • Riparian forests are highly diverse: reference sites average 15 species of trees and shrubs in the space of only about an acre.
  • Riparian forests are composed of different assemblages that shift along the elevational gradient of watersheds, depending on substrate, geomorphic conditions, and probably also simple chance.
  • These assemblages, while consisting of different species, follow predictable biological patterns.
  • Reference sites- preferably multiple ones- should be used in restoration to help us do restoration more effectively.

For the curious, here’s a short presentation on the study design, results, and potential applications. I hope to get around to actually publishing one of these days!


Sorry about the inelegant link: I promise it works. I’m always here, so if you’d like to learn more about RiVR, or use it in a project, email me at river.why.ecology -at- gmail and I’ll be happy to respond. You can also contact me through the Urban Creeks Council Facebook page.

Rivers and trees and woody debris


Rivers are dynamic and breathtaking things. The actions of physics combine with biological processes to create some of Earth’s loveliest and most important ecological systems. Rivers, their processes, and their associated vegetation directly or indirectly support a majority of the organisms on earth for all or part of their life-cycles. Riparian vegetation, including forests, is so closely integrated with the river itself that ecologically it is difficult to consider them as separate.

Rivers and streams exist because there is water on Earth, because of the force of gravity acting upon that water, and because of geomorphic conditions that cause water to accumulate and flow aboveground.

Groundwater and rivers, while they influence each other, are vastly different systems. Groundwater moves slowly through the earth, while rivers are decidedly more swift. And groundwater and streams feed each other depending upon the geology of a given area. We have gaining streams and losing streams: gaining streams are fed by groundwater sources, while losing streams feed the groundwater. Gaining streams are more common, due to the accumulation of available water that occurs when a larger area of land drains to a given stream. Losing streams are most common in areas of particular geologic fingerprint, such as Karst systems, and in arid regions.

Floods, considered by humans to be some of the most despised and destructive acts of nature, are important events that can generate major changes in the earth and its ecosystems – and, despite what we think, for the better. Technically, a flood is simply the response of a stream to a larger-than-typical input of water to the system. Flood flows, or storm flows, are what shape the river and its ecosystem. Smaller, more frequent floods form the active channel, or what we recognize as the river’s bed and banks. Larger, rarer floods, while powerful, do not exert a consistently significant force on the shape of the river. Quite the opposite: the river will withstand the force of larger floods and maintain its equilibrium condition if it is in balance, similar to the way an overfilled glass will maintain its shape and shed the liquid it cannot hold.


I encountered a result of a flood that occurred recently on a tributary to the Napa River. The above alder tree was alive (and apparently in good spirits) when it was ripped from the ground and pulled downstream by the relentless force of a spring 2016 flood flow (in fact, despite its horizontal state, it was still alive when I found it). The flood was so pervasive that the original site of the tree could only be discerned from the opening it left in the canopy. The trunk is now facing downstream, where previously unreachable regions of the tree can be examined from the comfort of the ground. Different species of lichen stratify with the height of the trunk. Already the stream appears to be assimilating it, as one might arrange a rug to accomodate new furniture in a room. The rootball is perfectly positioned to create a beautiful scour-pool already forming beneath it, and another small tree has been caught crosswise in the stream, helping it adjust to the new change in bed elevation. In an equilibrium stream, such things are minor adjustments to the overall poetry of the water moving through the landscape. Downed trees are not disasters; there will always be more trees, and the fallen merely create sunny openings where new trees can sprout and grow. The water finds its way, as it always does. The geometry of the stream remains as it ever was – the channel is as broad, the thalweg as deep, the substrate as well-distributed as it should be.


And there’s this incredible step-pool that’s developed downstream of the second downed tree, with the rest of the water migrating around the down wood. Eventually, this reach will break down and envelop this wood, possibly cover it entirely – and find a new microequilibrium in this twenty linear feet of stream reach. Woody debris is as critical to the health and structure of these streams as gravels and cobbles are. More so than boulders, woody debris, usually in the form of fallen trees from the riparian forest, is responsible for the creation of pools – critical habitat for native salmonids and many other aquatic species. Pools are resting places and refuge from predators. A commonly known koan of stream geomorphologists is “Riffle, Run, Pool, Glide”, referring to the four stream features identifiable by their form within the stream channel and frequently found in equilibrium streams. Riffles are fast-flowing and shallow, a major source of oxygen in the water. Runs, originating downstream of riffles – as all fisherpeople know – are where the food is and where the fish can be found feeding. Pools are important resting habitat. And glides are a transition between pool and riffle, shallower than pools but deeper than riffles, and where the river most often looks to be moving as a single water molecule. It’s all very cool to observe in nature.

Screen Shot 2016-05-19 at 7.47.26 PM

When the forests around streams are logged, it affects the stream ecosystem in deep ways. The principal process by which woody debris becomes available to the stream is tree senescence and death. If the forest is logged improperly – if only the old-growth trees are taken – this will limit the availability and quality of woody debris in the stream spanning into decades later. This shift in the forest can actually change the relationship of the stream to its fish populations. A normal distribution of tree ages, a universal law of nature, is a gradually descending curve with high numbers of young trees and low numbers of old trees. This makes intuitive sense – an area cannot accommodate as many large trees as it can small trees. A forest, like all ecosystems, is limited by space and resource availability.  The first photo in this blog post is a very old, dead conifer (probably a Douglas-fir) that is gradually sinking into the stream channel and creating a scour-pool beaneath it. The stream absorbs the impact of this woody debris and shifts its microhabitats (the riffle-run-pool-glide sequence) to accommodate the new feature.

The understanding of the relationship between forests and rivers by humans has, luckily, led to a dramatic change in the way riparian forests are managed. In California, most plantations now treat riparian areas as completely off-limits to logging. This is in response to regulatory directives from the Department of Fish and Wildlife regarding fish habitat and endangered species protection, which in the northern part of the state includes Northern Spotted Owl habitat (these owls nest exclusively in old-growth forest, and are an indicator species for the old-growth status of the forest). It’s easy for a trained forester to tell if a forest has been improperly logged, but most members of the general public think of forests as densely vegetated places with many small, closely clustered trees. Unfortunately, the forest creatures we still have with us co-evolved with a very different structure of forest habitat, and the decline of many of our native species is associated with our own ignorance of what forests should be – as is the increasingly common occurrence of hugely destructive, unstoppable wildfires. Vast swaths of forest with tons of small trees and very few or no large old trees are not natural and are not beneficial for many species of wildlife – or, as it turns out, for the humans living near them. More in a future post- we’re getting into fire season here in California and it’s likely to be a hot one.

Repairing trailside erosion

The winter soil-bioengineering season has come to an end, and spring is everywhere. The landscape displays every imaginable shade of green. This is when we start to see the benefits of our winter work pay off. The living structures we built are leafing out, which means their roots are already deeply rooted in the soil. This is good news for this old trail, and the creek that flows beside it. I walked it today; there are newts in the pools and the air is filled with the sound of birds and falling water.

IMG_8067 (1)

Trail cutting imposes particular stressors on a landscape. It alters the grade on both the upslope and downslope sides, changes hydrology patterns and soil stratification, and disturbs soil microorganisms, affecting soil cohesiveness. Old trails, particularly those cut prior to the advent of park master planning and mandated environmental assessment, will show their age in the form of damaging erosion patterns, aged fencing, and deferred maintenance of all sorts.

What’s the deal with this particular trail? First of all, it’s one of the oldest in the Bay Area. Second, it’s situated directly adjacent to a creek; urban stream drainages are notoriously erosive and unstable environments and generally not good places to site trails. Third, this is an off-leash trail. As evidenced by the lack of vegetation on the trailside streambank, trampling is constant and damaging, resulting in a stream bank almost totally devoid of living plant matter. Hundreds of dogs per day leap through the fence slats and down into the creek, then back up again. All of these factors spell trouble for a creek and the critters that live there.

What is to be done? There will be no decommissioning of the trail at this point in its life; it is well established and loved by the large community living in nearby cities. It’s a cornerstone of the park system here, connecting dozens of trailheads and recreational features. And most of the trail is in fine shape.

So, we compromise. By combining the efforts of local youth with the knowledge and tools of park staff, we can accomplish a great amount of work to remediate damage. In 2015 hundreds of feet of fencing were replaced and several dozen square feet of living willow structures built to take the pressure off the riparian ecosystem and help it begin to recover. We successfully decommissioned at least five bootleg trails (non-sanctioned trails caused by users ignoring park rules and going wherever they please).

Here are six willow wattle structures installed parallel to the slope to capture sediment from a new trail dip we built to channel water:


Here’s our structure today, at about 2 months old:


These leaves are all from individual willow whips sprouting even on this dry slope. The structure has already captured a large enough amount of sediment that it’s partially buried. That’s all sediment that isn’t going into the creek!

Just up the trail, behind the new fencing and slash we piled to discourage off-trail activity, the native vegetation is beginning to recover. This area was bare and compacted before we started work. It’s amazing how much nature can recover simply by removing a stressor.


To users of the the bootleg trail, it doesn’t look like your steps are doing any damage; but that’s because your steps are merely perpetuating the damage done by others before you. As long as the steps continue, the native vegetation can’t establish, and soil quality degrades. There is a purpose for all that trail planning! Part of the job of maintaining public parks is to ensure that the park benefits wildlife as well as people-and that means limiting human use.

Decommissioning a trail is an art, and not always simple to do. Many users believe they have a right to use the park in whatever way they choose. Unfortunately this attitude harms both nature and other users.

This bootleg was a veritable staircase leading right up to another bootleg trail, and so worn that it looked like it was supposed to be a trail. It was so heavily used that oak roots that used to be underground were now exposed:


And here’s the trail after our work:


The critical trick is to make the trail disappear. This discourages most users simply because the trail no longer looks like a trail. At first, people tried to continue climbing the trail, throwing brush aside and blazing a trail. But we persisted in replacing it. Four months after the work was performed, the native ferns and snowberry are coming back. Decommissioning of this sort is really an ideal approach, because it doesn’t involve changing policy or policing users. The trick is to change the trail from an inviting place to a place one wouldn’t think of going. I love low-tech solutions like this.

Despite the fencing and the signs advising owners to keep their dogs out of the creek, of course, I watched dogs romping through the creek on at least five different occasions today. This work that we do is largely to protect the ecosystem from those who don’t care or know any better, because the data indicate that around half of the trail users fall into one of those two categories. It’s unfortunate, but that’s the reality of maintaining a public park: undoing the damage caused by the public. Along with removing litter and clearing downed trees, repairing physical damage is a main mission of rangers. They, of course, are thrilled to have a crew helping them to get done all this work that they need to do, and the crew gains training in natural resource management. I hope that some of them will be rangers here someday.

These results are very encouraging for the first year of this project and I’m looking forward to spreading word of the positive results and getting more work done! I’ll post more before and after results soon.


Conservation vs. Recreation: When We Abuse Nature By Enjoying It

For those of us who love the peace and inspiration of a long walk in the wild, it’s hard to imagine that our very presence could be actively harming the ecosystems we’re supposedly communing with. It’s anathema to our entire philosophy as lovers of the outdoors. But it is increasingly being shown that our presence-each footfall, each brushing of a branch, each stream crossing-actively harms the organisms around us and reduces ecological function. That damage exists on a continuum, of course, but we all need to come to terms with our impact, and the responsibility we have to compensate for it.

On a trail near where I live, a trail where I have helped restore habitat, a rogue hiker- or hikers- have been maintaining a bootleg trail (a trail not planned or sanctioned by the park district) by breaking tree branches, moving natural debris, and trampling vegetation. When rangers tried to discourage use by posting advisory signage and blocking the trail with large branches, the hiker(s) responded by destroying the signs and pushing the blockages out of the way. Someone even sawed down a young redwood tree. These are people who have gone out of their way to enjoy their local regional park. What could possibly motivate them to destroy it?


Fencing is a message to stay on trail, not an invitation to go beyond it.

In a recent article in Outside Online, author Christopher Solomon describes the palpable conflict between recreational uses and conservation mandates in public wild areas. Our ethic of conservation is built largely around the creation and maintenance of natural areas for public use; it’s built into the funding structures that support parks and the missions of the agencies that set aside and maintain them. This may foster the belief that these public lands are all ours, and therefore we can go wherever, and do whatever, we please within their borders.

But that approach doesn’t work as a conservation ethic. Solomon writes,

“When we play in the mountains and forests, we think we’re simply having fun. (Leaving no trace! Communing with nature!) But whether we’re in closed or open areas, studies show that even Sierra Club-approved activities like hiking, cross-country skiing, and bird watching can negatively affect the environment more than you’d think. Take research in Boulder that discovered a roughly 100-yard “death zone” for songbirds on both sides of a trail, as one scientist put it, pointing to low nesting success and lower populations. Moose increased their movement by 33 percent, burning more energy, after encountering skiers, a study in Scandinavia found. In one not-yet-published survey of 218 studies that looked at the effects of recreation on wildlife, researchers found more evidence for impacts by non-motorized activities than by motorized ones.”

Based on what I’ve seen on my local trail, I believe it. People who use this trail believe that they- and their off-leash dogs- have the right to use the trail and any area around it however they please. They blatantly ignore signage asking them to keep their animals out of the stream to protect native fish, frogs, and newts. They believe they are entitled to create trails wherever they wish, no matter what those who are tasked with maintaining the park say. How is this responsible appreciation of our natural resources?

If we are to approach a sustainable balance with our rapidly deteriorating ecosystems, we must give up the misguided belief that our presence does no harm, and that we are entitled to use natural areas however we please. Especially in massively overpopulated areas like California, there is just not enough habitat left to sustain healthy wildlife populations. Solomon concludes: “As a recreation community, we should not only be prepared to accept… restrictions—we should also embrace and support them, if science tells us they work.”

Regional, state and federal land management districts go to enormous effort to study, understand and plan for the proper management of ecosystems in public areas. The very least that park users can do to honor that effort, and the wild places that we enjoy so much, is to respect boundaries and give nature some space.

Read The New Golden Rule of Playing Outside: Place First.

Wondering where the lions are

I had another dream about lions at the door;
They weren’t half as frightening as they were before. -Bruce Cockburn

The American lion was twice as large as the modern-day African lion.

The American lion was twice as large as the modern-day African lion. From tumblr @owoodsga.

I’m working on a presentation about restoration for a guest lecture at UC Berkeley. I’m trying to put the vast trajectory of restoration science into some kind of narrative that this class of students can meaningfully internalize. My main focus so far is the fact that our ecosystems are in the middle of a massive trophic cascade, and that this must be considered in restoration. (More on that later.) Essentially, our ecosystems, on account of a series of human and non-human stressors, have lost an astonishing amount of function and diversity over the past several thousand years, and been massively restructured. We no longer have mammoths, giant ground sloths, or North American lions. The only place we see mammals of even near comparable size is in the oceans, and these are very rare. Most people probably feel relief that there are no longer huge browsers and mesopredators wandering around our landscapes, but for myself, this knowledge triggers nothing but unease. And sadness.

This exercise has got me thinking about what we really mean when we intend to do restoration; what, when, are we restoring to? how do we compensate for the huge loss of ecosystem function since the extinction of the North American megafauna? really, how do we compensate for our societal incompatibility with large apex predators? Typically, when a mountain lion enters an urban area here in California, the reaction is one of semi-organized panic. Police officers mount watches; it’s all over the evening news; parents and pet-owners go stone-cold nuts on social media. Most of the time the cat has either been spooked and wants to hide or is looking for a place to sleep. The frantic vigil continues until, usually, the cat stalks off into the semi-wilderness from whence it came. We hardly ever hear about attacks, let alone fatalities attributable to these animals. Yet we are absolutely terrified of them. For a people who claim to be fascinated by nature, we sure have a lot of problems accepting it into our lives.

I remember watching the first season of Weeds and getting so angry about the scene where the child shoots the mountain lion in the face with a BB gun and it is seen prowling about their yard with blood streaming down its face. As if it was stalking the house, waiting for the children to come out in order to strike with tooth and claw. I believe that is how most people think of our lions, and it’s a shame.

When a mountain lion wandered into the moderately wooded city of Berkeley from nearby parklands in the middle of the night, it was promptly shot and killed by police officers who deemed it too dangerous to wait for a trained wildlife officer to arrive from Sacramento to tranquilize and relocate her. None of the officers present were trained in wildlife management measures. In all probability, the cat would have sniffed around a few yards, searching for the deer it had tracked down the quiet streets from the hills, and silently gone on its way, causing no harm. The chances of that lion harming a human were so minuscule as to be meaningless. Luckier cats likely make this short round-trip (1-2 miles from the parklands to the city) several dozen a times a year without anyone noticing.

I wonder what we’re so afraid of. An average of 1200 American children are killed in car crashes per year. How many children are killed by mountain lions per year?

Want to guess?

It’s fewer than one per year. In fact, only fifteen child fatalities have been attributed to mountain lion predation in the entire 20th century. Yet, we center our lives around our cars and we banish lions from our cities on pain of death.

I believe this dissonance comes from a place of imagined control; we believe we have enough control over our vehicles, and over the behavior of the other vehicles on the road, that it is safe enough to subject our children to the perils of passenger cars. Predators aren’t predictable. And they’re alien forms of life most
people haven’t been taught to understand. So we fear them. And we kill them.


Mountain lion cubs “treed” on a fence. A pack of coyotes is nearby. (c) Lori Iverson/USFWS Creative Commons.

I urge everyone who has any sort of admiration for lions- for nature in general- not to increase their fear of car trips- fear does nothing but harm- but to work on decreasing their fear of the things that are so unlikely to harm them. Lions, for instance, want nothing more than to avoid people. We frighten them, which is why hardly anyone ever sees one, even those of us who work in semiwild parks nearly every day. In my entire 35 years in the Bay Area, I’ve never seen one alive.

Human populations continue to increase, and increasingly there is nowhere for our native lions to go. They require vast amounts of open space that is swiftly vanishing, especially in California. Most importantly, we can’t pick and choose our palette of wildlife. When large predators are removed from an ecosystem, their loss triggers a cascade that is staggering to contemplate. To think that when wolves were extirpated from Yosemite, a process was triggered that resulted in destruction of the rivers. We cannot love rivers yet not love wolves. They are connected.

Let’s not destroy everything we love about nature out of fear.

Up among the firs where it smells so sweet, or down in the valley where the river used to be, I’ve got my mind on eternity. And I’m wondering where the lions are.

The Odd and Magnificent Prickly Sculpin

Cottus asper. (c)RiverWhy

Cottus asper. (c)RiverWhy

I stopped today at my favorite local reptile store to pick up various forms of live food for my ever growing zoo of fish and amphibians. I was asking for feeder fish, which are used to feed animals that refuse pellets or flakes. The man who was helping me asked what I was feeding. I replied “sculpins” — I have four of them living more or less peacefully in a community tank with two non-native green sunfish and some platys. At my reply, the man uttered, “hm”, and turned away to fetch my order. I figured he was not very interested in my fish, and somewhat gruff, like many of the folks who work there. Reptile people can be a lot like bartenders; the surliest ones are often those who tend to make the best drinks. I appreciate both reptile people and bartenders for this.

When the man brought my feeders back, he placed the bag on the counter and said something utterly unexpected. “When I was a boy in the UK”, he said with a big smile, “my favorite book was about a lobster whose only goal in life was to walk on land. His best friend was a grumpy sculpin. I’ve never forgotten that book, and every time I think of sculpins, it makes me a little choked up.” His gruffness was not gruffness at all. I told him I would bring a picture of my kids (the sculpins) back to show him, and he said that was all right, as long as I didn’t mind him getting teary-eyed if I did.

What is it about that love for something so common, yet so extraordinary, that stays with a man for his entire lifetime?

A great many people will never know what a sculpin is. My variety are called prickly sculpin, Cottus asper, and they are native to streams and lakes throughout the Pacific slope watersheds. They belong to the superfamily Cottoidea, encompassing over 750 distinct species all over the world. They are called prickly sculpin because of the rough texture of their skin when felt with a finger moving toward the head, similar to a cat’s tongue. Benthic fishes, they are skilled predators, striking lightning-fast after bugs and small fish on the stream bottom. And they stick to the bottom like glue; you’ll hardly ever see them in the mid to upper water columns. They are weird-looking, maybe even ugly; their faces make me think of a fat man behind the counter of a gas station in South Dakota with a stained T-shirt and a cigarette hanging out of his mouth, leaned back in his chair and leering at you, trying to decide whether you’re going to try and steal that bag of Funyuns. They’re gruff and grumpy as the best San Francisco bartenders. But as odd-looking as they are, there’s something alluring about them.

Prickly sculpins, and their cousins riffle sculpins, are not tolerant of poor water quality, so they’re one of the fishes we lose in urbanized watersheds with high pollutant load, artificial stream features or poor aquatic habitat. As predators, they demand a fairly high level of habitat intactness that will produce enough smaller critters for them to consume. I never remember seeing them as a kid, though I spent a lot of time in the streams of the Bay Area. I first handled one only a few years ago, doing stream surveys in East Alameda County, and recall distinctly how magical it felt to meet this new creature.

Most people revere trout as the ultimate stream fish; the vision of a leaping steelhead, shining in the light before splashing down into a rocky stream, is their aesthetic ideal. But prickly sculpins are my favorite stream fish. I think they’re perfect; the combination of their beautiful mottled coloration and their grumpy faces is just right. I love that they are neither perfectly beautiful nor perfectly ugly, but an intriguing balance of the two. It’s nice to know the sculpin man at the reptile store loves them, too.

Streams, snorkels, and golf courses

image1Today we were out testing a new survey method on a reach of a stream that we typically survey via electrofishing. Snorkel surveys basically consist of putting on a wetsuit (16 degree Celsius water is cold for us warm blooded critters), grabbing a snorkel and an underwater flashlight and poking into the pools to identify and count the inhabitants. It is a much less invasive survey method than electrofishing, in which an electrified probe is stuck into the water that shocks the fish so that they can be netted, measured and weighed. The fish are returned to the water afterward, but when we’re working with already stressed populations we like to use a less invasive alternative. This particular stream has totally dried up in sections for several years in a row due to the drought, so the fish have no choice but to oversummer in the remaining pools. So far, the pools have been expansive enough and the water cool enough that we have not lost our populations of native trout (Oncorhyncus mykiss) and California newt (Taricha torosa). But there is great concern for the viability of the populations.

A popular hiking trail runs right alongside this creek, and despite signage asking folks to keep their pets out of the water, dogs are constantly jumping in and disturbing the critical oversummering pools. These fish are evolved to endure prolonged drought, hunkered down in the oversummering pools. What they are not evolved to endure is dozens of dogs invading and disrupting their pools day after day throughout the dry season and causing water turbidity to go through the roof. Turbidity lowers dissolved oxygen (DO) content, making it more difficult for critters with gills to breathe. So, when we started our annual population surveys, we decided not to electrofish to avoid adding another stressor to these already stressed populations.

The survey was hearteningly successful, and the pools fairly ample and deep throughout the reach. But this is due to a surprising cause. There is a golf course upstream of this reach that, due to the watering of the turf, creates an additional groundwater input that augments the streamflow. Who would have thought that golf courses could be beneficial to fish? It’s a fascinating example of reconciliation ecology – anthropogenic (human) activity actually benefiting wildlife instead of harming it. We don’t know for sure, but there is a chance that if this golf course did not exist, we would not have found any viable pools at all. While more a happy accident than a purposeful act of conservation, it is certainly an important factor to be considered when planning species conservation efforts in a watershed heavily impacted by other human activities. In areas where humans have altered natural dynamics so drastically, nature needs all the help it can get.

River Physics

river.0Rivers meander in much the same way that snakes slither—their forward movement is not only lateral but also longitudinal. A time-lapse map of a river’s channel is like the revealing of some great, ancient secret. The simple movement of water through the landscape is one of the most powerful forces on Earth.

Rivers and streams are fascinating, deeply complex creatures. They are hugely influential ecological pathways, contributing to essential ecosystem processes both above and below the surface. The critical watershed-scale work of the river is to transport a balance of water and sediment downstream to the receiving water source (ocean, lake, bay, et cetera). The ecosystem processes that spring from that single task are enormous in scope and are critical to a large majority of California’s wildlife.

The geomorphic characteristics of watersheds change dramatically from their headwaters to the river mouth (geo = earth, morph = shape, form). The word “geomorphology” describes the behavior of the physical structure of rivers and the study of that structure. The upper reaches of streams are composed of large boulders and very steep slopes, and are tightly confined within their valleys. The action of water on this rock, the river’s substrate, is partially responsible for the creation of the sediment-water balance. Because of the steepness of these mountain streams, their channels are typified by a step-pool structure with very little meandering. This is the reason that mountain streams are clear, clean, and unusually musical.

Where these steep valleys open up, a new source of sediment joins the river—bank sediments created by the natural erosive process of meandering. Rivers that are allowed to move freely within their meander belts are continuously eroding and rebuilding their meanders. A river can meander while still remaining confined to its valley because, in its snakey movement, erosive energy is transferred downstream as well as laterally.

flickr_looping_amazon_river_2These middle areas of the watershed both collect and deposit sediments; they are deposited in the form of point bars, which form the inside of a meander. A well-sorted point bar, with fine sediments higher on the bar and progressively coarser sediments toward the active channel, is one sign of a healthy river. This process occurs because the slower water is moving, the more sediment it will drop out of suspension. When water slows down on the high edge of a point bar, the sands and silts drop out; in the thalweg (deepest point of the channel) fast water will roll larger bed material downstream while maintaining its suspended sediment load. Rivers in equilibrium will not excessively erode nor aggrade their sediment. Rivers out of equilibrium—well, we will hear much more about those later.

Finally, in the lower reaches, rivers begin to branch out into tidal marsh complexes typified by very fine, rich sediments and braided channels. Nearly the entire San Francisco Bay was once bordered by vast expanses of tidal marsh. Tidal marshes provide both critical ecosystem processes and benefits to human communities, including nutrient and pollutant filtration, carbon sequestration, and flood mitigation. Intact marsh complexes actually protect coastal communities from storm surges—a fact powerfully demonstrated by Hurricane Katrina.

This incredible process creates beaches and nourishes tidal marshes and the biotic community that relies on riparian corridors—not only in California, but in watersheds around the world. There is something about the universality of river physics that is both electrifying and oddly comforting—that even if the river is damaged, the stream channelized, the energy is still out there somewhere, waiting for its time to go to work once again.


Credit to Flickr: leoffritas (Creative Commons 2.0) and @josephstromberg at Vox for the super cool imagery.

What is nature for?

11225072_10207160433190570_7063498719917835900_nAn apprentice of mine, in his entry interview, upon being asked why anyone should care about nature, replied after only the slightest hesitation, “Well – because it’s the most beautiful thing there is.” This has gone down in history as possibly the best interview answer ever uttered.

Beginning this tiny insignificant dot of a blog, at the beginning of my thirteenth year as a restoration ecologist, I wonder, near-constantly, what nature should mean to a person. To a people. To all people. Increasingly, it seems that we’re no longer a part of it. That we’re drifted off into a universe entirely of our own making – a universe essentially devoid of the wonderful chaos of a system governed by the laws of nature rather than the laws of man.

Yet wonderful things happen when those who have been disconnected from the natural universe check back in. Despite the fact that I’m an insufferable curmudgeon, some of my greatest satisfaction has come from sharing my love of the natural world with others. The young people I work with are among my greatest inspirations. I can’t say there’s hope, exactly; often there isn’t. Often there is the exact opposite of hope. But I think a life lived in awe of the natural world, in constant curiosity, in the pursuit of both understanding and beauty, cannot be a life wasted.

I would want everyone to care about our natural world enough to wonder how it works, why it is there, and what it means to them personally and to us, the human race. To wonder, and then to discover.

I suppose this blog, then, is to speak to anyone willing – anyone wondering – what nature is for, what it means, what it can give – anyone questioning the relationship of humankind to nature — to wade through the muck at the edge of the floodplain – to take in the sounds of the wind in the trees, the insects moving, the splash of water – to move toward the water’s edge.

To part the reeds, and to prepare to be quietly amazed.