Category Archives: Peer Reviewed Article Review

drought

Alarm bells are beginning to sound on drought risk in western North America and around the world, including some important and populous food growing regions.

Here’s an article in Science talking about “an emerging North American megadrought”:

Severe and persistent 21st-century drought in southwestern North America (SWNA) motivates comparisons to medieval megadroughts and questions about the role of anthropogenic climate change. We use hydrological modeling and new 1200-year tree-ring reconstructions of summer soil moisture to demonstrate that the 2000–2018 SWNA drought was the second driest 19-year period since 800 CE, exceeded only by a late-1500s megadrought. The megadrought-like trajectory of 2000–2018 soil moisture was driven by natural variability superimposed on drying due to anthropogenic warming. Anthropogenic trends in temperature, relative humidity, and precipitation estimated from 31 climate models account for 47% (model interquartiles of 35 to 105%) of the 2000–2018 drought severity, pushing an otherwise moderate drought onto a trajectory comparable to the worst SWNA megadroughts since 800 CE.

Science

Here’s an article in Earth’s Future (from the American Geophysical Union, which I consider prestigious) talking about some other regions with high drought risk.

The multi‐model ensemble shows robust drying in the mean state across many regions and metrics by the end of the 21st century, even following the more aggressive mitigation pathways (SSP1‐2.6 and SSP2‐4.5). Regional hotspots with strong drying include western North America, Central America, Europe and the Mediterranean, the Amazon, southern Africa, China, Southeast Asia, and Australia. Compared to SSP3‐7.0 and SSP5‐8.5, however, the severity of drying in the lower warming scenarios is substantially reduced and further precipitation declines in many regions are avoided. Along with drying in the mean state, the risk of the historically most extreme drought events also increases with warming, by 200–300% in some regions.

AGU

So, our species has identified the problem and identified solutions, but is continuing to fail to actually do anything. This is a little like the coronavirus, where early action could have been cheap and effective compared to the drastic action required when the problem became really obvious to even the densest politicians. It’s unlike the coronavirus in that once the problem becomes obvious to even the densest politicians, there may be no effective measures that can be taken, even maximally disruptive ones.

The mention of the Amazon and Southeast Asia are particularly concerning to me. These are both important food growing regions and biodiversity hot spots.

bye bye bumblebees

The latest charismatic species to be at risk of disappearing – bumblebees, according to Science. It’s a simple story – they just can’t handle the heat.

Climate change could increase species’ extinction risk as temperatures and precipitation begin to exceed species’ historically observed tolerances. Using long-term data for 66 bumble bee species across North America and Europe, we tested whether this mechanism altered likelihoods of bumble bee species’ extinction or colonization. Increasing frequency of hotter temperatures predicts species’ local extinction risk, chances of colonizing a new area, and changing species richness. Effects are independent of changing land uses. The method developed in this study permits spatially explicit predictions of climate change–related population extinction-colonization dynamics within species that explains observed patterns of geographical range loss and expansion across continents. Increasing frequencies of temperatures that exceed historically observed tolerances help explain widespread bumble bee species decline. This mechanism may also contribute to biodiversity loss more generally.

Science

debt as a measure of natural capital depletion?

This sprawling article in Ecological Economics talks about human civilization as a “superorganism” that exists only to dissipate energy, fouling its environment in the process. What I found somewhat interesting was the links it tries to make between natural capital depletion and financial debt.

Simultaneously, we get daily reminders the global economy isn’t working as it used to (Stokes, 2017) such as rising wealth and income inequality, heavy reliance on debt and government guarantees, populist political movements, increasing apathy, tension and violence, and ecological decay. To avoid facing the consequences of our biophysical reality, we’re now obtaining growth in increasingly unsustainable ways. The developed world is using finance to enable the extraction of things we couldn’t otherwise afford to extract to produce things we otherwise couldn’t afford to consume.

Economics for the future – Beyond the superorganism

I’m not sure this article has a coherent story to tell, but I find it interesting to think what kind of indicators we might be able to look at to tell if an ecological reckoning might be around the corner. The prices of food and energy certainly come to mind. Financial debt, if it is indeed a measure of how much our expectations of the future are out of line with our capacity to innovate and to produce the energy and other materials and find the waste sinks we need to keep going. But there is clearly a lot of noise and short-term fluctuations in all these signals that might make it difficult or impossible to come up with any kind of useful predictive index.

bacteria, viruses, and fungi, oh my!

In the category of new diseases to worry about, and just in case you have not yet perused the latest issue of the Journal of Fungi, Candida auris is a really dangerous yeast fungus making the rounds in hospitals.

On the Origins of a Species: What Might Explain the Rise of Candida auris?

Candida auris is an emerging multidrug-resistant yeast first described in 2009 that has since caused healthcare-associated outbreaks of severe human infections around the world. In some hospitals, it has become a leading cause of invasive candidiasis. C. auris is markedly different from most other pathogenic Candida species in its genetics, antifungal resistance, and ability to spread between patients. The reasons why this fungus began spreading widely in the last decade remain a mystery. We examine available data on C. auris and related species, including genomic epidemiology, phenotypic characteristics, and sites of detection, to put forth hypotheses on its possible origins. C. auris has not been detected in the natural environment; related species have been detected in in plants, insects, and aquatic environments, as well as from human body sites. It can tolerate hypersaline environments and higher temperatures than most Candida species. We explore hypotheses about the pre-emergence niche of C. auris, whether in the environmental or human microbiome, and speculate on factors that might have led to its spread, including the possible roles of healthcare, antifungal use, and environmental changes, including human activities that might have expanded its presence in the environment or caused increased human contact.

beware the powerful house cat lobby

House cats have hired a major lobbying firm to promote their interests, as the song bird special interest attacks continue to escalate.

Okay, that’s my onion-like joke headline. But apparently, there is a vicious academic debate about just how much of a risk domestic cats pose to biodiversity when they are allowed to range outdoors. There is also a values conflict between people who feel very strongly about the welfare of individual animals, both wild and domestic, and people who feel very strongly about ecosystem functions and services. And obviously, there are lots of people who have strong feelings about all these things, and may have some internal conflicts to resolve.

There was one turn of phrase in this article I particularly liked: describing cats as “sentient, sapient, and social individuals”. I looked up sapient in the Websters 1913 dictionary:

Sapient
Sa”pi*ent
 (?), a.
 [L. sapiens, -entis, p. pr. of sapere to taste, to have sense, to know. See Sage
, a.
] Wise; sage; discerning; — often in irony or contempt.

Where the sapient king
Held dalliance with his fair Egyptian spouse.
Milton.
Syn. — Sage; sagacious; knowing; wise; discerning.

the emerging science of aquatic system connectivity

JAWRA has a nice literature review on this topic, particularly the science of how wetlands function hydrologically based on their placement in the watershed. I can see a lot of useful applications in both urban and rural hydrology. In my experience, and particularly on the urban end, there is very little hard science built into our legal and policy frameworks on this topic, for example in municipal drainage codes and stormwater management requirements.

species persistence and ecosystem fragmentation

Here’s a new paper on relationships between biodiversity and ecosystem fragmentation/connectivity. If I could go back to school and just study whatever I wanted for fun and without economic constraints, maybe this would be it. My basic question would be how much you can really expect to optimize patches and corridors within urban and suburban areas, agricultural areas, and protected natural lands to preserve as much ecosystem function as possible while still supporting a human population.

Species persistence in spatially regular networks

Over the past decades, numerous studies have provided new insights into the importance of spatial network structure for metapopulation persistence. However, systematic work on how variation in patch degree (i.e., the number of neighbors of a patch) in spatial networks modifies metapopulation dynamics is still lacking. Using both pair approximation (PA) and cellular automaton (CA) models, we investigate how different patch network structures affect species persistence while considering both local and global dispersal. Generally, the PA model displays similar metapopulation patterns compared to the CA simulations. Using both models, we find that an increase of relative extinction rate decreases global patch occupancy (GPO) and thereby increases the extinction risk for local dispersers, while increasing patch degree promotes species persistence through increasing dispersal pathways. Interestingly, patch degree does not affect local species clumping in spatially regular patch networks. Relative to local dispersers, species with global dispersal can maintain the highest GPO, and their metapopulation dynamics are not influenced by spatial network structure, as they can establish in any patch randomly without dispersal limitation. Concerning species conservation, we theoretically demonstrate that increasing patch connectivity (e.g., constructing ecological corridors) in spatial patch networks would be an effective strategy for the survival of species with distance-limited dispersal.

bike lanes need to be protected

I’ve always felt that drivers are more reckless on streets with bike lanes. A new study confirms this. So bike lanes need to be separated and protected to be safe. This is especially acute where I live in Philadelphia, where we have faded, poorly marked bike lanes and vehicles constantly blocking the bike lanes causing bikers to merge in and out of sometimes fast moving, often angry traffic including trucks. Still, if I have to get hit by a car on a relatively slow residential street, I think I would rather be side-swiped rather than run over from behind. Riding with the flow of traffic scares me because if an inattentive driver hits you from behind while you are making a legal stop at a stop light or stop sign, you could very well die, whereas if you are sideswiped, you have a reasonable change to crash land on the curb or run into a parked car, pedestrian, or something else to absorb some energy and slow you down hopefully without killing you. None of these things should ever happen of course, it is just cowardly and ignorant politicians and bureaucrats who are putting their citizens and children at risk when solutions are available.

rain measurement using cameras

This article is about estimating rainfall using ordinary surveillance camera footage and computer algorithms to process the videos. Measuring rainfall with physical rain gauges is subject to a lot of error, and so far the only real way to reduce the uncertainty is to add more gauges, which of course costs money. Radar can be used to improve our knowledge of what is going on in the spaces between rain gauges, but ultimately the radar-based estimates still end up being calibrated to the gauges. New methods to improve accuracy for a given gauge coverage, and/or reduce cost and gauge coverage while maintaining accuracy, would be welcome.

Advancing opportunistic sensing in hydrology: a novel approach to measuring rainfall with ordinary surveillance cameras

“Opportunistic sensing” represents an appealing idea for collecting unconventional data with broad spatial coverage and high resolution, but few studies have explored its feasibility in hydrology. This study develops a novel approach to measuring rainfall intensity in real‐world conditions based on videos acquired by ordinary surveillance cameras. The proposed approach employs a convex optimization algorithm to effectively decompose a rainy image into two layers: a pure rain‐streak layer and a rain‐free background layer, where the rain streaks represent the motion blur of falling raindrops. Then, it estimates the instantaneous rainfall intensity via geometrical optics and photographic analyses. We investigated the effectiveness and robustness of our approach through synthetic numerical experiments and field tests. The major findings are as follows. First, the decomposition‐based identification algorithm can effectively recognize rain streaks from complex backgrounds with many disturbances. Compared to existing algorithms that consider only the temporal changes in grayscale between frames, the new algorithm successfully prevents false identifications by considering the intrinsic visual properties of rain streaks. Second, the proposed approach demonstrates satisfactory estimation accuracy and is robust across a wide range of rainfall intensities. The proposed approach has a mean absolute percentage error of 21.8%, which is significantly lower than those of existing approaches reported in the literature even though our approach was applied to a more complicated scene acquired using a lower‐quality device. Overall, the proposed low‐cost, high‐accuracy approach to vision‐based rain gauging significantly enhances the possibility of using existing surveillance camera networks to perform opportunistic hydrology sensing.