Tag Archives: ecology

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.

Pennsylvania’s Integrated List

Pennsylvania has released its DRAFT 2018 PENNSYLVANIA INTEGRATED WATER QUALITY MONITORING AND ASSESSMENT REPORT. This might seem esoteric and of interest to just a few, but it’s worthwhile to think about what U.S. water quality regulations are supposed to accomplish and how much they are actually accomplishing.

  • The authority to regulate the water quality of “navigable waters” rests with Congress, under the concept that water quality is important to interstate waters. In practice, most rivers, streams, and lakes that do not dry up at any point during a typical year are covered. There is an enormous, long-running legal fight over water bodies at the margins of this definition, such as wetlands that are connected to larger bodies of water sometimes but not all the time.
  • Congress makes the law, the EPA is required to implement them, and the EPA in most cases delegates this to state-level agencies, although it can supervise them and, in theory at least, take over at any time. This very occasionally happens.
  • State level agencies are required to map all the water bodies in the state that come under these regulations, break them up into segements, and specify the “uses”, such as type of aquatic ecosystem and type of recreation, to be protected for each and every one.
  • Then they are supposed to collect data and determine whether each and every segment is “attaining” each and every use.
  • If any segment is not attaining its use, the state is supposed to determine an exact cause.
  • If the cause is a specific pollutant, it is supposed to identify all the sources of that pollutant, how much it needs to be reduced for the use to attain, and how much each source of the pollutant is required to reduce their discharges.
  • The results of this process, called “total maximum daily load”, are not immediately enforceable. Now the numbers have to flow down into enforceable permits and other programs.

It’s all very logical and straightforward. Now here are some of the problems.

  • The federal and state agencies don’t have the funding, personnel, and expertise to do the data collection right. This means that the determinations are often done on very little data, by people of questionable expertise, and the conclusions are easy to challenge by permitted polluters with some means. “Polluters” as I use the term here are not necessarily bad actors – they are cities, towns, businesses and farmers. In short, civilization causes pollution and the idea is to control the amount and type to what the environment can assimilate.
  • When a reasonable amount of data is collected, it is usually paid for by the polluters themselves. Again, they are not necessarily bad actors. They may be perfectly ethical people who want to be regulated based on accurate information. But sometimes not, and either way there is a conflict of interest involved. Data collection is also an effective delay tactic – when data is inadequate, the problems are not well understood and the most appropriate solutions are not easy to identify, a data collection effort can be a good compromise among all parties involved and an alternative to endless legal action.
  • Even when there is a lot of data, the science is complicated, there is a lot of uncertainty, and this makes any required reductions fairly easy to challenge by those with financial means.
  • Cities and towns are required to limit stormwater pollution, but in practice stormwater pollution is generated by thousands or millions or individual property owners. Fixing this would require changing the way we build and use land. Technological solutions exist, and are not even necessarily high-tech or expensive, but there is enormous uncertainty built into current political and institutional arrangements.
  • Agriculture is almost entirely unregulated, and is an enormous source of pollution. It is controlled only through a patchwork of voluntary and incentive programs funded mostly at the state level. Some states do this better than others, but it is never adequate.
  • The concept of chemical “water quality” as we tend to think of it does not really guarantee the restoration of functioning ecosystems. The legal framework probably could be implemented in a way that would do this, but there is a critical lack of system understanding even among educated professionals, and even if a critical mass of people had that understanding, there is enormous resistance to change built into our institutions.
  • The regulatory agencies tend to go after a few big polluters, because that is how they get the most bang for their buck. Numerous small polluters, who collectively add up to most of the pollution, don’t get addressed. The big polluters are able to delay enforcement, sometimes indefinitely, through a variety of legal tactics. Third party advocacy groups get involved in lawsuits and add to the fray.

Bringing Nature Home

I’m reading Bringing Nature Home: How You Can Sustain Wildlife with Native Plants by Douglas Tallamy. It’s a pretty interesting book because he is an entomologist and writes from that perspective. His message is pretty straightforward: most plants have compounds that help them defend against insects, and native plants have evolved for millions of years with insects that specialize in eating them. These insects are overwhelmingly the base of the food chain that supports everything else up to birds and larger animals. Replace the natives with ornamentals from elsewhere, often specifically bred to be unattractive to insects, and there are a lot fewer insects. The ecosystem doesn’t function any more, even if the plants kind of look similar to the way the functioning ecosystem used to look. Add to this the long list of devastating pests and diseases that have been imported along with alien ornamental plants, and ornamental plants that have escaped into the wild to further devastate ecosystem function, and the case is pretty strong.

Trends in Ecology and Evolution 2018 Horizon Scan

Trends in Ecology and Evolution does an annual “horizon scan” of hot topics for the coming year. Below is their list for this year. The article is open access.

  • “Thiamine Deficiency as a Possible Driver of Wildlife Population Declines” – Thiamine is a form of vitamin B. Pollution and subtle changes in algae eaten by fish and birds may be causing its depletion. This is not fatal in and of itself but may be weakening animals so that they succumb to other things.
  • “Thiamine Deficiency as a Possible Driver of Wildlife Population Declines” – It’s affecting deer, moose, and elk in North America, and now reindeer in northern Europe.
  • “Breaks in the Dormancy of Pathogenic Bacteria and Viruses in Thawing Permafrost” – Some viruses and bacteria may be able to lie dormant in permafrost for thousands of years, long enough for populations of animals and humans to lose their immunity. Permafrost is melting.
  • “RNA-Based, Gene-Silencing Pesticides” – Messing with RNA can control pests such as the mites affecting honey bee colonies. The good thing about this form of genetic engineering is that it is not passed down from one generation to the next.
  • “Genetic Control of Mammal Populations” – Islands such as New Zealand are trying to use gene drives to wipe out pests such as rats. Not control them, but completely eliminate them once and for all. There are some obvious benefits, but this is also a little terrifying when you think that we now have the ability to engineer the complete extermination of a particular species in short order.
  • “Use of Lasers in Commercial Deep Water Fishing” – Sounds a little scary, but it’s an alternative to dragging heavy nets that destroy the bottom. 
  • “Use of Metal–Organic Frameworks (MOFs) for Harvesting Atmospheric Water” – This is literally sucking humidity out of the air. Of course, we can all do this with our air conditioners and dehumidifiers, but that takes a lot of energy and this process apparently does not.
  • “Aquaporins Engineered to Increase Plant Salt Tolerance” – This is messing with plants so they can grow in saltier soil. Seems like a good idea, except there is potentially moral hazard here because good farming practices should stop good soil from becoming salty in the first place.
  • “Effect of Culturomics on Conservation Science, Policy, and Action” – This is just processing and analyzing large amounts of text.
  • “Changes in the Global Iron Cycle” – Iron can actually be a limiting nutrient in some ecosystems, particularly in the oceans. Melting glaciers and ice bergs have an effect on this – I won’t pretend to fully understand it.
  • “Underestimation of Soil Carbon Emissions” – Soils contain a lot of carbon, the decay of organic soils may give off more carbon than thought, and there could be an accelerating feedback loop as warmer temperatures accelerate the decay, which in turn cause warmer temperatures.
  • “Rapid Climatic Changes on the Qinghai–Tibet Plateau” – This affects the Southeast Asian and Indian monsoons, among other things.
  • “International Collaborations to Encourage Marine Protected Area Expansion in the High Seas” – Okay, I guess they had to throw in something positive.
  • “Belt and Road Initiative in China” – Basically, China talks a good game on sustainability and the potential is there, but the on-the-ground reality is not very sustainable so far.
  • “Potential Effects on Wildlife of Increases in Electromagnetic Radiation” – This is about cell signals causing cancer. In wildlife, because this journal is about wildlife. But it’s a little concerning for us humans too.

the trial of the century

Peter Singer is arguing for the importance of the lawsuit brought by children against the United States government for failing to address climate change.

The plaintiffs claim that their government’s active contribution to climate change has violated their constitutional rights to life, liberty, and property. When the government sought to prevent the case from being heard, the federal district court of Oregon issued a historic ruling that “the right to a climate system capable of sustaining human life is fundamental to a free and ordered society.”

When Juliana v. United States is appealed to the US Supreme Court, as seems inevitable, the question may no longer be whether the preservation of the plaintiffs’ constitutional rights requires “a climate system capable of sustaining human life”; it undeniably does. Instead, the Court will have to decide whether it is willing to heed the scientific evidence that the actions of the US government are indeed jeopardizing the survival of human life on our planet. If it is, even the most conservative justices will find it difficult to escape the conclusion that the government is in violation of the US Constitution.

Vertical Farms

I’m listening to Dixon Despommier’s 2010 book Vertical Farming. I was expecting an architect-y, design-y kind of book, but it turns out Despommier is an ecologist and his main message is ecological. He believes the current system of farming has been a disaster for the planet’s ecosystems and that it is also headed for a catastrophic collapse with current and increased demands for food. His argument is to bring most agriculture into high rises in urban areas where it can be very carefully controlled. This would also allow the re-wilding of most land currently devoted to agriculture worldwide.

He argues that this an economical choice when the value of ecosystem services is considered (although he simultaneously makes this argument and rails against the idea of monetizing ecosystems at all). I’m a little more than halfway through the book and I haven’t gotten to the part where he argues that the cost of using artificial light rather than taking advantage of free and abundant sunlight is offset by other costs. I assume he is going to get to that. I also wonder if he is going to address the idea that removing one limit (in this case, the amount of food that can be produced with the planet’s available land and sunlight) in the long term could allow us to continue growing the population until we hit another limit. These are a couple questions I am curious how we will address, but overall I am enjoying the book. He does briefly bring up the idea that this could be a step toward moving into space or colonizing other planets.

May 2018 in Review

Most frightening stories:

Most hopeful stories:

  • There are some new ideas for detecting the potential for rapid ecological change or collapse of ecosystems.
  • Psychedelics might produce similar benefits to meditation.
  • Microgrids, renewables combined with the latest generation of batteries, are being tested in Puerto Rico.

Most interesting stories, that were not particularly frightening or hopeful, or perhaps were a mixture of both:

abrupt ecological change

Being able to forecast abrupt ecological change might be a good idea.

Abrupt Change in Ecological Systems: Inference and Diagnosis

Abrupt ecological changes are, by definition, those that occur over short periods of time relative to typical rates of change for a given ecosystem. The potential for such changes is growing due to anthropogenic pressures, which challenges the resilience of societies and ecosystems. Abrupt ecological changes are difficult to diagnose because they can arise from a variety of circumstances, including rapid changes in external drivers (e.g., climate, or resource extraction), nonlinear responses to gradual changes in drivers, and interactions among multiple drivers and disturbances. We synthesize strategies for identifying causes of abrupt ecological change and highlight instances where abrupt changes are likely. Diagnosing abrupt changes and inferring causation are increasingly important as society seek to adapt to rapid, multifaceted environmental changes.