Tag Archives: urban ecology

How an effective drought reshapes an urban bird community (a thesis seminar)

A few years ago we began what we hoped would be a long-term study of how urban water policy and water use by people affects the diversity and distribution of other species that share the city’s habitats with us. The “city” in question is the Fresno-Clovis metro area in California’s Central Valley, and the “we” in question refers to the multidisciplinary team I pulled together to successfully compete for one of the Urban Long-Term Research Area (ULTRA) – Exploratory Award grants given by National Science Foundation and US Forest Service. That grant was how my research directly benefited from President Obama’s stimulus package in his first term, and the relatively small two-year award came with a great deal of (eventually dashed) hope that there would be money to actually grow it into a real long-term research network.

We had a unique opportunity in Fresno-Clovis to study how human water use in cities influences biodiversity in a “found experiment” since the City of Fresno had just begun installing water meters in this quite large arid southwestern city. We were able to survey the city for birds, plants, and human perceptions of water before water metering went into effect in 2013, and stretch our NSF grant dollars to continue studying them in the years after. It has been fascinating to watch this urban ecosystem change over these years, and grapple with the challenge of tracking how people’s choices have changed and how biodiversity is changing in response to what people do in their yards and throughout the city. Our challenge became further complicated by another unplanned perturbation of water in this system: the onset and deepening of the drought over California in these recent years. The NSF grant funded a number of graduate thesis projects (and undergraduate students helping with the research) at Fresno State, and their work has opened up new questions for us to pursue, even as we look for other ways to fund the work for the long-term.

Today I am back in Fresno (having recently moved to North Carolina State University to join a new interdisciplinary faculty cluster for Leadership in Public Science, in case you missed that news) for the culmination of another Masters thesis from this project. My student Stephanie Slonka will defend her thesis today, where she has conducted the first detailed analysis of how bird species diversity and abundance have changed in Fresno-Clovis over recent years by comparing data from bird census (from the Fresno Bird Count) and habitat surveys from several years before water metering went into effect and more recent post-metering years. The increased cost of metered water combined with the drought (and calls from the California Governor) has caused people to reduce the amount of water they poured into their yards, creating a more “effective drought” with much less water available in the landscape. Meanwhile, the bird community in Fresno has also changed significantly, showing lower number of species and smaller overall population in recent post-meter/drought years compared to the pre-metering period. What does this mean? If you want an answer to that, you can come to the Fresno State campus today to hear Stephanie defend her thesis where she explores these dynamics.

post-metering-model

 

A thesis defense is a landmark event both for the student and the advisor, and I am proud to see another student achieve this today. Stephanie’s thesis exit seminar will happen at 4:30PM today, in Science II, room 110. Here is her seminar flyer with further details if you wish to attend.

Winter song

I love these wintry days in the Central Valley when its dirty brown air has been washed out by the infrequent (but not this winter, gracias El Niño) rain and wrung out to dry with cottonball clouds hanging as if on invisible clotheslines across an impossibly blue sky. Days like this I can even see snow on the mountains of the Sierra Nevada from my office window, pulling my gaze away from the computer screen to wander off daydreaming…

View from my office window, drawing me away from my screen to the snow-frosted mountaintops of the Sierra Nevadas in the distance. This iPhone's camera doesn't do justice to what my eye sees...you may have to squint into the middle distance to glimpse the mountains underneath the floating clouds.

View from my office window, drawing me away from my screen to the snow-frosted mountaintops of the Sierra Nevadas in the distance. This iPhone’s camera doesn’t do justice to what my eye sees…you may have to squint into the middle distance to glimpse the mountains underneath the floating clouds.

Such days I imagine were the norm in this valley a century ago, before our vehicles and agricultural industry started filling up the air with so many of our effluents as to turn this beautiful air into some of the least breathable in the nation, a murky brown veil hiding the mountains on most days of the year. Yet the people keep coming to fill up this valley, remaking it in our own industrial image, flattening the topography and bending the natural and ancient rhythms of this land and atmosphere to our will. Days like this remind me of those rhythms, of what once was, what might have been, and what could be again in this beautiful place, even as the vision of those mountains seems to melt away the grimy sealed glass pane on my office window out of which I goggle at that impossibly blue sky like a goldfish trapped in a bowl.

Urban conifers against that impossibly blue winter sky. There be Great Horned Owls in some of these trees...

Urban conifers against that impossibly blue winter sky. There be Great Horned Owls in some of these trees…

That window glass is not thick enough to keep out the occasional soft hooting of the young Great Horned Owls hidden in the branches of those conifers, where they were raised a summer ago. And this morning, as I stepped out onto the external staircase, I was startled by the liquid burbling notes of a song that is common throughout the spring and summer around here, but shouldn’t be so loud so early in the year. A House Finch was sitting high up in one of the trees singing his heart out against a background humming with the urban noises of building atmospheric devices and traffic in the distance, and roaring with an occasional airplane flying over.

Looking out east from his high perch, I wonder if the House Finch noticed the snow on the mountains, or heard the chirping of the winter migrants in the trees nearby, but even if he did, these weren’t enough to dissuade him from following whatever internal hormonal clock was telling him it was time to start singing to attract a mate. Already, and it isn’t even the middle of January yet. Global warming, is it, or just the local warming effect from the urban heat island? No matter, this boy is already serenading the ladies about the bountiful spring to come.

Meanwhile, the chipping sounds you hear at the end of the sound clip above might well be the mild panic setting into the heart of the migrant Yellow-Rumped Warbler foraging in the branches nearby, perhaps wondering if it was time to leave its winter ground already even though the air felt cold and the clouds spoke of more rain to come.

Its been a topsy turvy winter (or a few) in California, and living in these disconnected urban landscapes beneath the gaze of those parched snow-covered mountains must be discombobulating even to the wild creatures trying to make this ever stranger land their home. I know the feeling well.

What do we do with the aliens among us?

Over at the excellent The Nature of Cities blog, editor David Maddox is hosting the site’s 8th Global Roundtable, this time focusing on the challenge of invasive and exotic species in cities. David recently invited me (as one of the regular contributors to the blog) to take part in this roundtable with a brief essay stating my perspective. My essay was posted to the roundtable earlier this week, along with about a dozen other perspectives from urban ecology practitioners around the world. Please visit the forum site to read all the different views, and share your own by commenting in the discussion – I really hope you will do so. All of the authors are reading comments and participating in the discussion actively over the next few weeks. So I hope to see you there. Meanwhile, as promised, here is a somewhat expanded (or more rambling) version of my essay:

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Aliens! Invasives! Species that don’t belong here and are taking over the ecological roles of native species. Those weeds choking the understory of native forests. The Starlings and House Sparrows pulled out of Shakespeare’s England that now so tragically dispossess native birds of their nest holes!

How can we tolerate these aliens among us? How fast can we get rid of them? Exterminate the aliens!

Pretty exotic flowers that make our suburban gardens so lovely. Grasses from halfway around the world that knit the dense mats of our lush lawns. Lovely succulent plants and delicately spined cactuses that dot our newly water-wise xeric landscapes and window ledges. Plants that flower and fruit out of their time and place, maybe year round.

Where can we get more of them so our gardens in Arizona look just like the ones in England or Singapore or Australia? So the corporate landscapes in Bangalore make the techs returning home from Silicon Valley feel like they never left California? Like the peacocks whose plaintive calls and stunning displays might make California feel more like Gujarat!

A Peacock in California

We humans sure do have a passionately ambivalent relationship with nature. Never more so than when it comes to the plants and animals we move around among our global habitats. The very words we use to describe them are so heavily laden with value judgment: invasive, alien, exotic. We move them around with us so we can evoke the landscapes of our childhoods halfway around the world, or recreate imagined ones from somewhere else entirely. We wage war on them when they refuse to stay in the gardens and pens where we put them, and start exploring new worlds on their own.

Humans are the most invasive species on Earth. Our cities, ecosystems we build and replicate around the world, are also focal points from which other species have invaded native habitats. Just as wanderlust defines our species, so does the biophilia which makes us take living elements of our habitats with us wherever we go. Carrying a suite of species as sources of food, comfort, companionship, and beauty, has always been part of our cultural and evolutionary baggage. Invasiveness is something evolution tends to reward, and our own evolutionary success springs from a certain restless invasiveness.

Ever since our ancestors realized they could control the lives of other plants and animals, so they could rely on them to feed the body and nurture the mind during lean times, humans have been moving species around the world. In scattering across the planet, we deliberately carried many such species to help fill our bellies, beautify our homes, and stave off homesickness in strange new lands. Meanwhile, other species latched on to our coattails, hitching rides around the world with this walking ape, this most efficient global form of transport and dispersal they had ever encountered! Wittingly and unwittingly, we set off evolutionary changes in species we want, species we tolerate, and species we hate, as they all became part of a human-ecosystem-complex we have set about replicating across the world. These places we call cities often serve as outposts from which many other species launch their invasions into surrounding native habitats. And so we end up with the dilemma of wanting to move some species with us to our new homes, but struggling to keep some of them from spreading out of our gardens and farms and taking over entire native ecosystems.

It is in the very nature of life to try to take control of its immediate environment, to transform resources to nurture itself, and to expand outwards to occupy and transform new places. Invasiveness, the ability to “invade” new habitats, is always favored by evolution. Natural selection rewards traits that allow species to grow rapidly, to outcompete other species vying for the same resources, or simply eat them as food. Moving to a completely new habitat, while quite risky, can also bring the benefits of escaping the co-evolved competitors and predators and parasites that might hold a species back in their native range.

So most species are always sending out their seeds and young ones into new habitats by whatever means available. Most often, these dispersals end in tragedy, but every once in a while, they open up vast unimagined new territory for the species, and new evolutionary opportunities to express and expand the range of their genetic potential. Humans, increasingly, provide some of the most perilous, exciting, and potentially high-risk/high-reward challenges to other species: if you can attach yourself to a human, and figure out how to survive in the strange new urban world, you stand a good chance of surviving in this Anthropocene, sometimes in places far from your evolutionary home.

We have spent millennia figuring out how to make some species grow where and when we want them. Meanwhile, other species have latched on to our coattails making the most of this new mode of hyper-efficient long-range dispersal: the hairless ape that travels the world, with baggage. Only recently have we realized the often devastating consequences of bringing exotic species into native habitats. Invasive species fuel some of the most intense debates among conservationists, often laden with hysterical rhetoric about alien, exotic, invaders who must be exterminated.

Invasiveness is in the nature of the most successful species. To know the truth of this, one need but look in the mirror. We are, after all, the most successful invasive species now occupying the planet! But our success has been the downfall of many other species, and we are only just now grappling with the consequences of our invasiveness. Yet the most passionate debates about what to do with invasive species, heavy with the metaphor of war and genocide and extermination, tends to somehow tiptoe around this elephant in the room: the fact that we humans are the ultimate invasive species on Earth, and are responsible for most other invasions that are destabilizing native ecosystems worldwide. Indeed, displaced species often form a big part of our own preferred global habitats.

Cities are where most humans now live, where we often first introduce new species, and whence some of these species launch invasions into new habitats. Indeed, cities themselves seem like invasive habitats proliferating in and destabilizing ecosystems around the world. Cities must therefore be central to our efforts to address the challenge of invasive species. Cities embody the contradiction between our desire to control nature, shaping entire ecosystems to suit our purposes, and our growing desire to conserve nature and biodiversity.

Urban gardens

How do we reconcile our innate desire to build habitats for our own biological and cultural needs with a growing awareness that perhaps we should leave nature alone? It must start with owning our central role in this ecological conundrum. It is time we accepted our responsibility, as the ultimate invasive species that has moved entire ecosystems around and built new ones. It requires us to transform our role beyond the dichotomy of active perpetrator / passive bystander in the drama of invasive species. We must embrace the role of more deliberate stewards of the lands we now dominate.

As more people recognize the problems of invasive species, many now seek ways to build native species friendly urban landscapes. Ecologists are good at understanding the effects of non-native species in native habitats, and in raising the alarm about invasive species. We haven’t done enough to actually transform the practices that contribute to the invasive species problem. Urban ecologists have been lax in engaging with one group who arguably wield the greatest influence on this challenge: gardeners, nurseries, and landscapers. The growing desire to make urban gardens native-friendly is constrained by lack of available species options in local nurseries, and of expertise in nurturing native species. Ecologists must fill this knowledge gap by developing better ways to support native species in urban habitats in partnership with the people who actively transform the landscape.

Forget “leave nature alone”; in cities we must become better ecosystem engineers, designing habitats more consciously to enhance native biodiversity while limiting opportunities for non-native species. We must also recognize that some non-native species have become naturalized to play important roles in their adoptive ecosystems, so simply eradicating them is not the ideal solution. People move and grow plants and animals to fulfill complex social, cultural, aesthetic, and emotional needs. We must develop a broader vision of biodiversity that includes both the ecological roles of species and their cultural resonance for people. Balancing these will be key to managing invasive species in and around urban landscapes.

Humans will continue to move species around, despite conservationists’ (and agriculturalists’) best efforts to limit the movement of exotic species into regions outside their native range. Some of these species can and do become invasive in their new habitats. As good gardeners in the city, we will therefore also have to keep a close eye on all the species in urban ecosystems to make sure they don’t escape and start threatening native habitats nearby. At the same time, it is also worth remembering the plight of the House Sparrow, that ultimate city slicker introduced around the world as part and parcel of the global urban template. Alarmingly, it has recently disappeared quite mysteriously from many of its native cities in Europe and Asia. If the species were to somehow go extinct in its native range, at least its emigre populations, like the House Sparrow diaspora in the Americas, may remain the only living populations of a threatened species! We therefore have to be careful even in our efforts to eradicate non-native species lest we destabilize ecosystems, or drive species to extinction in unexpected ways.

Leaving nature alone is not really a viable option in the social-ecological systems we call cities. Instead, our respect for nature, and our growing enthusiasm for enhancing native species diversity, must be tempered by Constant Vigilance (if I may borrow the wise Mad-Eye Moody’s words) when it comes to the interlopers from elsewhere.

How the White-Crowned Sparrow changes its tune to be heard through the urban din

Last October, I was invited by Laurel Serieys (a graduate student at UCLA)  to present a paper at The Wildlife Society’s 20th Annual Conference in a symposium on how urbanization can cause wildlife populations to diverge by altering behavioral, physiological, and genetic aspects of populations occurring in cities compared to non-urban areas. This is an emerging field of research as we are beginning to build a better understanding of how different cities are as habitats for many species, and the different ways by which they may adapt to city life – or not. This approach is part of the research strategy which should help explain some of the broader patterns we are observing in the distribution of biodiversity in the world’s cities.

I spoke about the effects of urban noise on bird song, based on the excellent Masters thesis project by my (now former) graduate student Jenny Phillips, who studied migratory White-Crowned Sparrows spending the winter in California’s Central Valley. Jenny has since gone on to a Ph.D. program at Tulane University, working in the lab of Elizabeth Derryberry, who was on her MS thesis committee (and with whom I intend to continue collaborating to extend this research).

Photo of White-Crowned Sparrow sitting in a fence

A white crowned sparrow framed in the demarcated landscapes of California’s Central Valley. Photo by Madhusudan Katti, 2008.

I just remembered that TWS was recording talks and sessions throughout the conference, and went looking to see if my talk was recorded. Indeed it was! So if you are interested in hearing about some of Jenny’s and my work on urban bird song, have a listen to my talk on this page, which shows you my slides coupled with my ghati-accented voice:

Singing in the urban din: the effects of anthropogenic noise on song structure in urban birds

Note: the audio had glitches when I tried listening through Safari, but worked fine on Google Chrome; YMMV.

Here’s my abstract for that talk:

Female birds often use male song as an indicator of mate quality; thus the study of song provides insights into reproductive success. Song structure is constrained by the acoustic environment with selection favoring songs that transmit best through available channels given ambient noise and atmospheric conditions. Ecology_specifically those components of the environment that influence sound transmission_thus influences the cultural evolution of songs. One relatively new selection pressure on many birds’ song, is anthropogenic noise, from car traffic as well as industrial machinery and other urban sources. Urban noise resonates at low frequencies and has been shown to influence song frequencies in sedentary populations of song sparrows, great tits, and blackbirds. Increase in ambient noise has also been shown to diminish discriminatory ability in female zebra finches. I first present a brief conceptual overview of the potential and documented effects of urban noise on bird song and behavior. I then share results from ongoing studies of the effects of noise on song in White-crowned Sparrow, Zonotrichia leucophrys gambelii, a long distance migrant wintering in urbanizing areas of central California. Songs and noise were recorded across the urban-rural noise gradient in Fresno-Clovis Metropolitan Area and compared for acoustic differences in frequency and duration. Modulated note components of the song, the buzz and trill, decreased in bandwidth with increasing noise. The duration of the buzz portion can also be predicted by noise and habitat type. This trend towards short, pure tones in noisy areas is likely an adaptation to be better heard through the roar of the city. Playback experiments also found increased latency to respond to territorial simulations under high ambient noise levels. This may contribute to a breakdown of territoriality in urban habitats. Anthropogenic noise is likely to be an important driver of population divergence due to urbanization.

More birds and plants in the world’s cities than expected – a new paper from my NCEAS team

Tea with sparrows

A special present to celebrate this Darwin Day: the publication of the first paper from my global collaboration to study patterns and processes in biodiversity among the world’s cities. This first fruit of a collaboration that started 3 years ago under the aegis of the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara has just been published in the Proceedings of the Royal Society B:

M. F. J. Aronson, F. A. La Sorte, C. H. Nilon, M. Katti, M. A. Goddard, C. A. Lepczyk, P. S. Warren, N. S. G. Williams, S. Cilliers, B. Clarkson, C. Dobbs, R. Dolan, M. Hedblom, S. Klotz, J. L. Kooijmans, I. Kuhn, I. MacGregor-Fors, M. McDonnell, U. Mortberg, P. Pysek, S. Siebert, J. Sushinsky, P. Werner, and M. Winter 

A global analysis of the impacts of urbanization on bird and plant diversity reveals key anthropogenic drivers

Proc R Soc B 2014 281: 20133330-20133330 doi: 10.1098/rspb.2013.3330

The paper has 24 co-authors, from 10 countries, and involved a number of other collaborators who contributed data in some way. It is easily the biggest scale project I’ve ever been involved with, and one that promises to be very productive over the next few years. We started in 2011 by building perhaps the largest database of bird and plant diversity in cities, with 147 cities analyzed in this paper, and have continued to work on analyzing the data and expanding the database. This paper is the first in what we plan to be a series of articles analyzing the distribution of bird and plant species in urban areas worldwide to develop a deeper understanding of how cities interact with biodiversity. As such, this overview article has been a big first step in getting our work through peer review and into publication so the rest of the world—you—can read and see what we have discovered.

It is gratifying to see that there is broad interest in our results. The BBC News posted a report covering our paper even before the paper was available online, and the BBC World Service will shortly be interviewing Mark Goddard, one of the coauthors. Meanwhile, the Australian Broadcasting Corporation’s program The World Today spoke to coauthor Nick Williams earlier today, and you can hear his interview online in the show’s podcast. US media hasn’t quite woken up yet, so let’s see how much interest there is on these shores.

I will be writing more about this research, and explaining our findings in greater detail in a blog post or two over the coming few days (as and when I find time to finish writing the posts in between classes and committee meetings). For now, let me share this press release I helped put together for NCEAS:

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Julie Cohen
(805) 893-7220
julie.cohen@ucsb.edu
Pat Leonard
(607) 254-2137
pel27@cornell.edu

February 12, 2014

Cities Support More Native Biodiversity Than Previously Thought
Researchers at UCSB’s NCEAS compile the largest global dataset of urban birds and plants, which shows world’s cities retain a unique natural palette.

(Santa Barbara, Calif.) — The rapid conversion of natural lands to cement-dominated urban centers is causing great losses in biodiversity. Yet, according to a new study involving 147 cities worldwide, surprisingly high numbers of plant and animal species persist and even flourish in urban environments — to the tune of hundreds of bird species and thousands of plant species in a single city.

Contrary to conventional wisdom that cities are a wasteland for biodiversity, the study found that while a few species — such as pigeons and annual meadow grass — are shared across cities, overall the mix of species in cities reflects the unique biotic heritage of their geographic location. The findings of the study conducted by a working group at UC Santa Barbara’s National Center for Ecological Analysis and Synthesis (NCEAS) and funded by the National Science Foundation were published today in the Proceedings B, a journal of the Royal Society of Biological Sciences.

“While urbanization has caused cities to lose large numbers of plants and animals, the good news is that cities still retain endemic native species, which opens the door for new policies on regional and global biodiversity conservation,” said lead author and NCEAS working group member Myla F. J. Aronson, a research scientist in the Department of Ecology, Evolution and Natural Resources at Rutgers, The State University of New Jersey.

The study highlights the value of green space in cities, which have become important refuges for native species and migrating wildlife. This phenomenon has been named the Central Park Effect because of the surprisingly large number of species found in New York’s Central Park, a relatively small island of green within a metropolis.

Unlike previous urban biodiversity research, this study looks beyond the local impacts of urbanization and considers overall impacts on global biodiversity. The research team created the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities).

Findings show that many plant and animal species, including threatened and endangered species, can flourish in cities, even as others decline or disappear entirely. Cities with more natural habitats support more bird and plant species and experience less loss in species as the city grows. Overall, cities supported far fewer species (about 92 percent less for birds and 75 percent less for native plants) than expected for similar areas of undeveloped land.

“We do pay a steep price in biodiversity as urbanization expands,” said coauthor Frank La Sorte, a research associate at the Cornell Lab of Ornithology. “But even though areas that have been urbanized have far fewer species, we found that those areas retain a unique regional flavor. That uniqueness is something that people can take pride in retaining and rebuilding.”

Conserving green spaces, restoring native plant species and adding biodiversity-friendly habitats within urban landscapes could, in turn, support more bird and plant species. “It is true that cities have already lost a substantial proportion of their region’s biodiversity,” said Madhusudan Katti, a faculty member in the Department of Biology at California State University, Fresno. “This can be a cup half-full or half-empty scenario. If we act now and rethink the design of our urban landscapes, cities can play a major role in conserving the remaining native plant and animal species and help bring back more of them.”

The human experience is increasingly defined within an urban context, the authors noted. They maintain it is still possible for a connection to the natural world to persist in an urban setting, but it will require planning, conservation and education.

“Given that the majority of people now live in cities, this group’s synthesis of data on plant and urban plant and animal diversity should be of broad interest to ecologists as well as urban and landscape planners,” said Frank Davis, NCEAS director.

# # #

Note to editors: Frank Davis is available at frank.davis@nceas.ucsb.edu or at (805) 892-2502. Downloadable images are available at http://www.news.ucsb.edu/node/013947/cities-support-more-native-biodiversity-previously-thought.

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Of course, feel free to also contact me if you have questions about the paper or our ongoing research into global urban biodiversity patterns, and if you need a reprint pdf of the paper. I would love to hear your thoughts on this work.

Urban gardens

 

Is drought a natural disaster in a desert? Only if you’ve buried your head in the sands of the Cadillac Desert

Just saw this post by Tom Yulsman on Discover blogs:

The U.S. Bureau of Reclamation made an historic announcement today: It is cutting its water releases from Lake Powell to their lowest levels since the giant reservoir on the Colorado River began to fill in the 1960s.

Thanks to increasing demand for Colorado River water, and decreasing supply resulting from profound drought, Lake Powell has dropped to less than half full. To help slow the decline,  the Bureau of Reclamation will reduce the amount of water Lake Powell releases downstream toward Lake Mead in 2014 by almost 1 million acre-feet. (An acre-foot is roughly the amount of water a U.S. household uses in a year.

But that means Lake Mead, the other giant hydrological savings bank on the river — and the supplier of 90 percent of the water used by Las Vegas — could be headed for even more serious trouble in coming years.

That prospect has prompted the water czar for southern Nevada to float the idea of asking for federal disaster assistance to cope with dwindling water supplies. Quoted in the Las Vegas Review-Journal, Pat Mulroy, head of the Southern Nevada Water Authority, compared the drought and its effects to Hurricane Sandy, which inundated large parts of the Northeast in fall of 2012:

“This is as much an extreme weather event as Sandy was on the East Coast. Does a drought not rise to the same level as a storm? The potential damage is just as bad.”

I started to write a comment there, found it turning rather long, so figured I might as well share my thoughts here.

This news should make it clearer that our mortgage payment on all the thoughtless and heedless development in the Cadillac Desert (Marc Reisner’s evocative phrase) which is based on borrowing resources from nature without finding ways to replenish them, is now due (or overdue). And so we have to figure out a way to back out of the ongoing unsustainable development of cities and farms throughout the US southwest.

It is interesting to think of Vegas seeking federal disaster relief assistance to deal with this water crisis, although I’m not sure what federal dollars can do if the natural water supply itself is dwindling. What do those seeking federal assistance have in mind for the money they may get from taxpayers elsewhere? Is it for changing the landscape and nature of development to reduce water use, or to put in more/longer straws deeper down into the reservoir so we can suck it dry faster? Does this request for federal disaster relief funds also mean that we are acknowledging that Vegas itself (and other cities like it) is a man-made disaster, not this decade-long drought which is part of what happens in desert regions?

Yulsman also links to this time-lapse animation of satellite images from Google’s Earth Engine to show the dramatic growth of Las Vegas over the past 3 decades, mirrored (in a manner of speaking) in the shrinking waters of Lake Mead over the same time period. Here’s the last frame of this animation, from 2012:

Vegas Landsat timelapse 1024x558

Does that look like a natural disaster to you? Or more like the not-so-gradual unfolding of a man-made disaster? One that anyone with even a passing acquaintance with the ecology of the region should have anticipated, but no one in any position of power thought to stop or even slow down. And now, after a decade-long drought (which, in a desert, is a surprise to whom, exactly?), we are being asked to treat the completely foreseeable (Cadillac Desert was published in 1993!) water shortage as a natural disaster on par with Hurricane Sandy, and therefore deserving of federal assistance?

While some of the socioeconomic effects of droughts may be similar to those of storms, in as much as they inconvenience the conduct of business as usual, our response to drought cannot be the same because there are fundamental ecological differences between these natural phenomena. It is possible (if ill advised) to recover from storms and hurricanes by rebuilding infrastructure and houses, and to pick up the pieces. It is also possible to redesign those cities with architectural and engineering solutions that might increase resilience to future storms. Many civilizations/nations have managed to survive / thrive in hurricane-prone areas for long periods of time throughout history, because those disasters, while causing damage, do not fundamentally reduce the amount of natural resources available for our use; if anything the heavy rainfalls can actually enhance the fertility of the regions for agriculture. Prolonged droughts, which are characteristic of desert regions, on the other hand, have a tendency to wipe out civilizations that build up beyond their natural resource means. The very name of Phoenix, Vegas’ big brother to the east and rival to the affections of Colorado river water, is testimony to cities past that have crumbled in the desert.

Phoenix, Las Vegas, Los Angeles, many smaller cities, as well as major farm areas like Imperial Valley, have all flourished over the past half a century owing largely to dams and canals and pipes that have allowed us to harness and redistribute water across the entire region in defiance of natural hydrological cycles. Did we really think we could get away with this forever without paying some cost? If we build cities and farms that consume more water than is naturally available (remember why these parts are called deserts!), it is inevitable that we will face such “disasters”, and once the rivers and aquifers are sucked dry, we won’t really have anywhere else to turn. The American Southwest is littered with archaeological sites that are testimony to such overreach by past civilizations which eventually bit the proverbial dust in these deserts.

We really have to face up to that long-term history and the ecological reality of living in and building a civilization in a desert region. There is no way to sustain any city in the long run if its water footprint exceeds the natural supply, however many straws we stick into the aquifers. Any long-term solution has to incorporate serious changes to the nature of development in the region, which must reduce water use and incorporate better ways to conserve water and try to replenish the aquifer instead of continuing to grow as these cities have been doing for some decades now.

I rather doubt that’s what they have in mind for the federal disaster relief dollars: a rethink and reorientation of the entire pattern of development in the region, with the goal of actually halting further growth and bringing our use of natural resources back in line with the natural rate of replenishment of those resources. If society intends federal disaster relief funds to mitigate the effects of such disasters and to try to prevent their recurrence, I have a humble suggestion for Las Vegas: use the funds to shut down or move the casinos and golf courses and other excessively thirsty unsustainable businesses (and the people working in those sectors) out of the area. That would be a good start towards avoiding future disasters, no?

On food, pollinators and what makes me scared (guest post by Maria Schewenius)

A long year ago and a few thousand miles away, I enjoyed my first lovely home-cooked Swedish meal in my then new friend Maria Schewenius’ flat, barely a week after I had flown there to start my sabbatical. Along with the moose patties and potatoes,

A traditional Swedish meal on Maria's balcony

A traditional Swedish meal on Maria’s balcony

the delicious meal Maria whipped up also included a salad featuring the freshest of tomatoes,

Tomatoes

Fresh tomatoes growing on an urban balcony

basil,

Basil, fresh as it gets

Basil, fresh as it gets

and other herbs

Herb garden in the balcony

Container garden full of herbs

Herbs in the balcony

Herbs and flowers

grown organically right there on the relatively small balcony of her (4th floor, if I remember correctly) flat!

Maria is a young urban ecologist working with the Stockholm Resilience Center on a number of projects of global import, including the Cities and Biodiversity Outlook (in which I played a small part) and URBES, among other things. As evident from the above photos, she is also an avid gardener, creatively making the most of the little open space and the few long days of summer sunshine available to her in the suburbs of Stockholm. Lovely flowers brighten up the containers which provide both beauty and food to this small scale urban farmer.

Edible blue flowers

Edible blue flowers

Flowerbed in the balcony

Flowers brighten up the balcony

Recently, though, she has had a personal realization of how much her little urban garden depends upon a larger network of species supported by the ecosystem of Stockholm, what we call ecosystem services in the jargon. Earlier today, she posted the following observation/lament on the apparent loss of an ecosystem service crucial to that supply of tomatoes which we enjoyed so heartily last summer.

My gracious hostess

My gracious hostess

On food, pollinators and what makes me scared:

A discovery and sudden realization yesterday made me terrified. My tomato plants, cocktail type according to the package, beef type according to the size the plants have actually grown to, have not only grown remarkably well since March but also been covered in pretty little yellow flowers for weeks. Now the flowers are falling off, and… nothing. Where little round tomatoes in abundance should now be emerging, weighing down the strong branches of the giant little plant, nothing appears.

Although the theoretical knowledge has been with me for years, it is the real experience, seeing with my own eyes, that truly makes me realize how fragile one of the most basic and vital of ecosystem functions is: pollination. Without honeybees, bumblebees and butterflies, which have been few and far between on my little balcony garden, my tiny scale food production system has crashed in the span of one single season. Suddenly I can start to imagine the potential effects of the global honeybee population decline, although it would be impossible to imagine the full effects if the pollinator system crashed – and I’m quite happy that it is.

As I am writing this, I glance at the gladiator of cocktail tomato plants next to me that with leisure nod along with the wind. One of the branches catches my eye: at its very end, well hidden beneath a labyrinth of leaves, three tiny pea-sized green tomatoes are emerging. There is hope.

Floral closeup

An urban floral closeup