Roomba vs. weeds

There’s a new robot that can weed your garden.

The Tertill was designed to survive outdoors. The latest prototype uses four-wheel drive to navigate a variety of terrains unsupervised and inward-tilting wheels so the robot can grip surfaces and extricate itself when it drives onto rocks and into holes. The Tertill also relies on capacitive sensors, which help it avoid obstructions and understand when to activate its weed-whacker.

The mechanism functions without machine-vision software, which Franklin Robotics says is not yet robust enough to distinguish weeds from plants, at least not at an affordable price. When the Tertill rolls over a plant that is shorter than its one-inch-high bumper, it assumes the plant is a weed, activates its trimmer, and cuts it. It turns away from plants that are taller than its bumper, and from metal collars that should be installed to protect seedlings.

By the time the Tertill goes on sale—likely via a crowdfunding campaign—the robot will have two more garden-related capabilities. It will wirelessly transmit data about plant and soil health to owners’ smartphones, so they can improve their gardens, and it will repel foraging animals such as rabbits and squirrels by moving and making noise when they approach.

cheetahs: going…going…gone?

In today’s depressing conservation news, cheetahs are in serious trouble.

Led by Zoological Society of London (ZSL), Panthera and Wildlife Conservation Society (WCS), the study reveals that just 7,100 cheetahs remain globally, representing the best available estimate for the species to date. Furthermore, the cheetah has been driven out of 91% of its historic range. Asiatic cheetah populations have been hit hardest, with fewer than 50 individuals remaining in one isolated pocket of Iran…

To make matters worse, as one of the world’s most wide-ranging carnivores, 77% of the cheetah’s habitat falls outside of protected areas. Unrestricted by boundaries, the species’ wide-ranging movements weaken law enforcement protection and greatly amplify its vulnerability to human pressures. Indeed, largely due to pressures on wildlife and their habitat outside of protected areas, Zimbabwe’s cheetah population has plummeted from 1,200 to a maximum of 170 animals in just 16 years – representing an astonishing loss of 85% of the country’s cheetahs.

Scientists are now calling for an urgent paradigm shift in cheetah conservation, towards landscape-level efforts that transcend national borders and are coordinated by existing regional conservation strategies for the species. A holistic conservation approach, which incentivises protection of cheetahs by local communities and trans-national governments, alongside sustainable human-wildlife coexistence is paramount to the survival of the species.

So it’s habitat loss and the relentless expansion of the human footprint, again. Are Africans just particularly callous toward the loss of the natural world? No, Africa is just one of the last places a lot of the large, charismatic animals are left. We had them elsewhere, but we have long forgotten them. Solutions exist. But I am in a pessimistic mood right now so I don’t think this time will be different, the declines and collapses will just continue to come faster and be more obvious until maybe some things will be done, but most likely they will be too little, too late. Too little, too late, but better than nothing. How is that for a silver lining?

 

Yellowstone

David Quammen (author of one of my all-time favorite nonfiction books, The Song of the Dodo: Island Biogeography in an Age of Extinction) has a long article in National Geographic about Yellowstone National Park which touches on some of the same things.

The Greater Yellowstone Ecosystem is bigger than any other park complex in the lower 48 states. And size matters. A resonant study published in the journal Nature back in 1987, by a young ecologist named William Newmark, revealed that among 12 national parks and park complexes in the western United States, all except two had lost mammal species in the years since they had been established, but that Greater Yellowstone, as the largest, had lost fewer species than almost all others. Most of those local extinctions had resulted not from direct human persecution—as the wolves of Yellowstone had been persecuted to oblivion—but from the natural processes of extinction characteristic of islands: When habitat is constrained within a limited area, animal populations remain small, and small populations tend to wink out, over time, because of accidental factors such as disease, fire, hard weather, and bad luck. Greater Yellowstone had lost less of its mammal diversity by natural attrition than had small parks such as Zion, Bryce Canyon, and Mount Rainier. Its size, evidently, had served it well.

Newmark’s original work has been challenged in some particulars during the decades since, but its basic conclusion remains sound: Size matters. The size of the Yellowstone complex helped preserve big, fearsome, wide-ranging, combative animals such as the grizzly, each one of which demands a large territory. No other park in the lower 48, apart from Glacier National Park along Montana’s Canadian border, now supports robust populations of the three greatest living North American carnivores—the grizzly, the wolf, the mountain lion—as well as such other predaceous animals as the wolverine, the coyote, the bobcat, and the red fox. Yellowstone is our wildest park south of the border complex that includes Glacier, in part because it’s our biggest.

The other good thing about geographical bigness is that, besides giving space to large predators with broad territorial needs, it usually encompasses habitat diversity as well as sheer space, thereby sheltering a greater variety of creatures at all levels of size, living all modes of life.

Because I am interested in island biogeography and I like the idea of having seminal papers at my fingertips, I looked up the Newmark article mentioned above.

A land-bridge island perspective on mammalian extinctions in western North American parks
WILLIAM D. NEWMARK
Nature 325, 430 – 432 (29 January 1987); doi:10.1038/325430a0

In recent years, a number of authors have suggested several geometric principles for the design of nature reserves based upon the hypothesis that nature reserves are analogous to land-bridge islands. Land-bridge islands are islands that were formerly connected to the mainland and were created by a rise in the level of the ocean. Land-bridge islands are considered supersaturated with species in that the ratio of island to mainland species numbers is higher than expected from the area of the island. As a result, the rate of extinction should exceed the rate of colonization on a land-bridge island, resulting in a loss of species that is suggested to be related to the size and degree of isolation of the island. If nature reserves are considered to be similar to land-bridge islands, because most are slowly becoming isolated from their surroundings by habitat disturbance outside the reserves, several predictions follow. First, the total number of extinctions should exceed the total number of colonizations within a reserve; second, the number of extinctions should be inversely related to reserve size; and third, the number of extinctions should be directly related to reserve age. I report here that the natural post-establishment loss of mammalian species in 14 western North American national parks is consistent with these predictions of the land-bridge island hypothesis and that all but the largest western North American national parks are too small to retain an intact mammalian fauna.

It’s easy to get depressed. Even if we preserved a lot of big open spaces, left them completely alone, and there were no such thing as pollution or climate change, a smaller nature would still be a less healthy nature. The only silver lining is that if we had a really thorough knowledge of how the shapes of preserved lands and the connections between determine their ecosystem health, we could theoretically come up with land use policies and practices to produce the best possible ecosystem health in the remaining space available.

There is research going on in this area:

A simplified econet model for mapping and evaluating structural connectivity with particular attention of ecotones, small habitats, and barriers
Wei Houa, Marco Neubertb, Ulrich Walzc
Landscape and Urban Planning
Volume 160, April 2017, Pages 28–37

Small habitats and ecotones are recognized as key structures in preserving biodiversity and maintaining landscape connectivity. However, most analyses of landscape pattern have not fully accounted for these elements. This leads to an underestimation of the landscape heterogeneity, especially at the local scale. This research aims to evaluate the structural connectivity for a source habitat (i.e., forest) with particular consideration of the roles of ecotones, small habitats, and barriers. A multi-buffer mapping procedure based on vector data is applied on two comparative test sites for mapping ecological networks (econets) which are composed of forest patches, ecotones, corridors, small habitats, and barriers. On this basis, several indices are proposed for quantitative evaluation of structural connectivity of econets. The application of the indices show that our approach can be useful for analyzing econet connectivity and identifying the roles of critical landscape elements, for example the barriers’ effect on overall forest connectivity. Within an econet, ecotones function as extension of forest edges which can increase the intrapatch connectivity; small habitats play the role of stepping stones which can enhance interpatch connections among forest habitats. The proposed econet model provides a generalized illustration of landscape connectivity and can be used to compare and monitor forest pattern.

December 2016 in Review

3 most frightening stories

  • The climate situation is not good. Concerns about food continue to surface, including from Bjorn Lomborg.
  • The water resources situation is not good. Asia may be headed for serious water shortages. 100 million trees have died in California during the current drought there. Drought and fire in the U.S. Southeast are an increasing problem and the region is unprepared.
  • The geopolitical situation is not good. If Russia did hack the U.S. election, it wouldn’t be the first election they have hacked. The wars in Afghanistan and Iraq are not over, and the rest of the greater Middle East is increasingly a mess.

3 most hopeful stories

3 most interesting stories

  • Scientists can synthesize proteins that could be incorporated in silicon-based life.
  • According to Bill Gates, “new genome technologies are at the cusp of affecting us all in profound ways”. But an article in Nature says we should not be too hopeful about living much past 100.
  • Maybe fish are not as stupid as we thought.

Katharine Hayhoe

Texas Monthly has an interesting profile of Katharine Hayhoe.

co-author of the last two National Climate Assessments and a reviewer on the Nobel Prize–winning Intergovernmental Panel on Climate Change, Hayhoe—the daughter of missionaries and the wife of a pastor—is herself an evangelical Christian. In her talks, she uses the Bible to explain to Christians why they should care about climate change and how it affects other people, from a poor family on the island nation of Kiribati who will be displaced by rising sea levels to an elderly couple in Beaumont who can’t afford to pay for air-conditioning in Texas’s increasingly sweltering summers. As she puts it, “The poor, the disenfranchised, those already living on the edge, and those who contributed least to this problem are also those at greatest risk to be harmed by it. That’s not a scientific issue; that’s a moral issue…”

If she was going to leave astronomy behind, Hayhoe wanted to do policy-relevant climate science. When she was considering graduate programs, she was thrilled to learn that Don Wuebbles, who had been instrumental in addressing the chlorofluorocarbon problem in the eighties, was the new head of the department of atmospheric science at the University of Illinois Urbana-Champaign. He would serve as her adviser for both her master’s degree and her doctorate. Under Wuebbles’s guidance, Hayhoe eventually began focusing on statistical downscaling, which was still a relatively new field when she started graduate school, in 1995. “There was very little of this being done at the time,” Wuebbles recalled recently, “and the methods were not capturing the full extent of the science, so she set about to develop a new technique and very successfully did so. She’s brilliant…”

Hayhoe’s first step is always to “genuinely bond over a shared value,” with an emphasis on that shared value’s being genuine. “The key is not to pretend; we can all smell someone who is not genuine a mile away,” she said. “If I’m talking to farmers or ranchers or water managers, I start off by talking about what we all care about, which is making sure we have water. And that, for many Texans, is almost as strong of a value as whatever it says in the Bible.” Her next step is to connect that issue to climate change. So when talking about water, she describes how climate change is changing rainfall patterns. “We’re getting these heavy downpours, and then we’re getting longer dry periods in between, and our droughts are getting stronger because the warmer it is, the more water evaporates out of our lakes and rivers and our soil,” she said. She tries to end her talks with solutions that inspire people, ranging from the personal (measuring your carbon footprint and installing energy-efficient light bulbs) to the large-scale (putting a tax on carbon). Hayhoe herself is most excited by the efforts of Elon Musk, the CEO of Tesla Motors and founder of SpaceX. “If I had to pick one person to save the world—and I don’t think any one person will but if I had to pick one—it would be him.” She is excited about the battery packs that Tesla is developing, declaring energy storage the “single technology that will make the most difference.”

clean water is not enough

This article presents evidence for the expected trend in biodiversity of riparian areas (whether lake, river, stream, etc. I can’t tell from the abstract) in response to urbanization. Large water features might be the one piece of the landscape that urban development has trouble erasing. But by changing the nature of the shoreline and adjacent habitat, you would expect a degradation in ecosystem quality, even if the water quality itself is perfectly fine (which it often is not, of course). The question is, could you design a shoreline and adjacent city that would support a significant fraction of the biodiversity and ecosystem function that was once there? In other words, a smaller nature that is still healthy? Or should we write off the idea of a high-functioning urban ecosystem and focus on protecting more wild areas? Well, I don’t know but I can guarantee that not making a serious attempt at either one will not lead to a good outcome.

Decadal declines in bird abundance and diversity in urban riparian zones, Landscape and Urban Planning, Volume 159, March 2017, Pages 48–61

Urbanization is frequently cited as a major driver of species losses worldwide; however, most studies in urban areas use a space-for-time substitution approach to document effects of urbanization through time. Ultimately, understanding the effects of urbanization on biodiversity requires long-term datasets. We examined long-term changes in bird assemblages at 12 riparian sites in the greater Phoenix metropolitan area and nearby Sonoran Desert region, featuring a range of human modifications and levels of water flow. Riparian areas in arid cities represent a key habitat type that is sensitive to human modification and supports high levels of species diversity. We used long-term data to: (1) explore variation in bird communities as a function of water permanence and degree of human-modification; (2) identify which environmental variables best describe differences found across riparian site types; and (3) assess how riparian bird communities, abundance, and species richness have changed through time. Engineered riparian sites supported more broadly distributed generalists; whereas, natural riparian sites supported more specialists. Sites with perennial flows had more vegetation and water compared to ephemeral sites and engineered sites had more impervious surface compared to natural sites. In nearly all comparisons, bird species richness, diversity, and abundance declined across riparian types during the period of study, even for common species. Bird communities in natural settings have changed more than communities at engineered sites. Overall, the riparian bird community is shifting toward urban dwelling, resident species that are characteristic of riparian sites with less water and more impervious surface.

more on Irving Fisher’s hydraulic machine

I’ve talked before about Irving Fisher’s hydraulic model of the economy. Here is a 2005 article that appears to discuss all its pieces and parts in detail.

How to Compute Equilibrium Prices in 1891

William C. Brainard and Herbert E. Scarf
The American Journal of Economics and Sociology
Vol. 64, No. 1, Special Invited Issue: Celebrating Irving Fisher: The Legacy of a Great Economist (Jan., 2005), pp. 57-83
Published by: American Journal of Economics and Sociology, Inc.
Stable URL: http://www.jstor.org/stable/3488117
Page Count: 27

 

more on the hollowing out of the middle class

This article from the Federal Reserve Bank of San Francisco talks about how the “wage premium” (how much educated workers make compared to less educated ones) seems to have stopped growing recently, although it is still large.

Recent Flattening in the Higher Education Wage Premium: Polarization, Skill Downgrading, or Both?

Wage gaps between workers with a college or graduate degree and those with only a high school degree rose rapidly in the United States during the 1980s. Since then, the rate of growth in these wage gaps has progressively slowed, and though the gaps remain large, they were essentially unchanged between 2010 and 2015. I assess this flattening over time in higher education wage premiums with reference to two related explanations for changing U.S. employment patterns: (i) a shift away from middle-skilled occupations driven largely by technological change (“polarization”); and (ii) a general weakening in the demand for advanced cognitive skills (“skill downgrading”). Analyses of wage and employment data from the U.S. Current Population Survey suggest that both factors have contributed to the flattening of higher education wage premiums.

Bradford Delong on…I’m not sure what

I have a sense that this long blog post by Bradford Delong contains some key insights or kernels of wisdom, but I just don’t quite have the language skills to translate from econospeak to English. I’ll give it a shot:

  • The human economy consists of two layers – the supply-and-demand market system governed by prices as envisioned in economics 101 textbooks, built on top of something more biological, our “propensity to be gift-exchange animals”.
  • Gift-exchange animals want to form relationships. We want wealth, but we want to feel like we have earned that wealth. We want to give, but we don’t want to feel like we are being taken advantage of.
  • What we are paid actually has a lot to do with what country, city and family we were born into, and all the knowledge and groundwork that was laid by the people who came before us in that location, and in the world/economy more generally.
  • Based on the above, he claims to be for some system of fair income or wealth allocation – “we need to do this via clever redistribution rather than via explicit wage supplements or basic incomes or social insurance that robs people of the illusion that what they receive is what they have earned and what they are worth through their work.”
  • He never quite explains what this would look like. He quotes another blogger, who suggests infrastructure, education, entrepreneurship, and something about removal of urban land use regulation that doesn’t quite make sense.

So I don’t quite know what my personal take-away from all this is but I feel like there is something there and if I ruminate on it for awhile it might come to me.