Tag Archives: biodiversity

October 2025 in Review

Most frightening and/or depressing story: The evidence for an increasing worldwide collapse in insect diversity and abundance continues to mount. What’s that you say, you don’t actually like bugs? Well, they are the base of the food chain (after plants) and generally indicators of biodiversity and healthy ecosystems more broadly. That’s right, the proverbial “canary in the coal mine” may have actually been a cockroach. There was also news this month that another “planetary boundary” has been breached. The biodiversity one that would cover insect collapse was already breached a long time ago, and this new one has to do with ocean acidification. Only two more to go for a perfect score of 9/9!

Most hopeful story: The seems to be some mixed evidence, tainted with industry and government propaganda in my opinion, but overall there are some hopeful signs that the global transition to renewable energy is real. It may be too slow and too late to avoid consequences, but it may also avoid the worst possible consequences.

Most interesting story, that was not particularly frightening or hopeful, or perhaps was a mixture of both: I mused about what it was like to be a child in the distant past of novels I have read, during my own youth, for my own children today, and for young adults I have interacted recently. We hear children are “anxious” and experiencing various crises, and I am not denying there is hard evidence of this, but with my own eyes I also see kids being somewhat safer, kinder, and gentler to each other than in the past. I hope it is possible to mitigate some of the negative effects of technology and other negative influences on kids today while also building on the positive trends.

https://www.goodreads.com/book/show/830502.It

biodiversity decline

Out of many doom and gloom topics, biodiversity decline may be the gloomiest, or at least the gloomiest that the global political system and public by and large are not thinking about. With climate change, at least we all know something is going on even if we are bickering about it and not doing enough 50 years after we needed to start acting in a concerted way. Anyway, global insect decline is just beyond shocking. Here is just one article hot off the presses:

Long-term decline in montane insects under warming summers

Widespread declines in the abundance of insects portend ill-fated futures for their host ecosystems, all of which require their services to function. For many such reports, human activities have directly altered the land or water of these ecosystems, raising questions about how insects in less impacted environments are faring. I quantified the abundance of flying insects during 15 seasons spanning 2004–2024 on a relatively unscathed, subalpine meadow in Colorado, where weather data have been recorded for 38 years. I discovered that insect abundance declined an average of 6.6% annually, yielding a 72.4% decline over this 20-year period. According to model selection following information theoretic analysis of 59 combinations of weather-related factors, a seasonal increase in insect abundance changed to a seasonal decline as the previous summer’s temperatures increased. This resulted in a long-term decline associated with increasing summer temperatures, particularly daily lows, which have increased 0.8°C per decade. However, other factors, such as ecological succession and atmospheric elevation in nitrogen and carbon, are also plausible drivers. In a relatively pristine ecosystem, insects are declining precipitously, auguring poorly for this and other such ecosystems that depend on insects in food webs and for pollination, pest control, and nutrient cycling.

For a more general overview of the insect decline issue, I suggest this paper: Insect decline in the Anthropocene: Death by a thousand cuts.

There is some debate about which causes are more important than others, but like climate change, the causes are pretty much known (and one of them is climate change). Destruction of natural ecosystems to clear land for urban areas and agriculture is the biggest and most obvious. Massive use of pesticides and other agricultural chemicals. Heat and drought. The spread of invasive species.

The destruction of nature is just sad for everyone who values nature for its own sake. For those who don’t, it’s a little harder to come up with the elevator pitch for why this matters. Pollination has huge and obvious economic value, but maybe we can replace natural pollinators with domesticated bees for the most critical crops.

Beyond pollination, insects are the base of the food chain. Their disappearance is actually a symptom of loss of plant life, since many of them are herbivores and depend on plants. We should be able to help a little bit just by conserving or replanting some of the native trees and other plants we know they depend on in our urban areas and on farms. A guy I know wrote a paper about this.

Insects, in their function as herbivores, are also critical in transferring energy, biomass (i.e. carbon), and nutrients up the food chain to everything from birds to amphibians to fish. So their loss is a direct cause of the loss of a lot of these other animals. But in terms of the food supply, we can probably produce chickens and pigs and cows without them I suppose. So it’s a little hard to tell that “conservative” uncle at the Thanksgiving table that there is some imminent tipping point where the bugs dwindle to a certain level and then we all starve to death. (“Conservative” is in quotes because a true conservative would be interested in, well, conserving things not destroying them.)

unifying “Green Area Factor” and “No Net Loss of Biodiversity” measures

Here in the US, implementing these types of policies seems mostly like a political pipedream at the moment. I could imagine a really smart developer doing this as a marketing scheme, maybe. maybe. But this is a great article that gives us a window into some things that are being tried in Europe (although, I also hear voices in Europe speaking longingly of the perceived lack of regulation in the US). I don’t know – our regulations may be equally strong or stronger in some areas like hydrology and water quality (which is missing from the framework discussed here btw) wetland and floodplain protection, and endangered species (although these are under constant political threat). Ideally in my view, species would not have to get endangered first before we will do anything for them.

More than the sum of its parts – Integrating the use of green area factor tool and biodiversity offsetting for no net loss urban planning

As part of the actions to fight biodiversity loss, the European Union is working on a restoration regulation demanding the principle of no net loss (NNL) state of biodiversity of urban green space. Applying this principle in urban planning may raise conflicts between biodiversity conservation and ecosystem services provision. Furthermore, integrating the NNL of biodiversity principle into urban planning cannot be isolated from existing planning tools or processes. Here we present a novel approach where the green area factor tool and biodiversity offsetting are integrated to achieve NNL of biodiversity in urban planning, while maintaining the necessary ecosystem services and avoiding the negative, unintended tradeoffs that may occur if only one of these tools is used in the planning process. We provide a model which combines the two approaches to create a holistic method to understand and govern both biodiversity and ecosystem services of urban greenery. The model is intended to be used as part of urban planning processes.

beech leaf disease

A new disease is threatening beech trees (Philadelphia Inquirer, paywalled) in the U.S. We don’t want to lose our beeches like we did our chestnuts. Beeches have some similar features in that they make up a significant amount of our eastern forest canopy (like chestnuts used to), produce fatty nuts that feed birds and other species, and their leaves serve as host plants for insects that feed birds and other species. It is not clear yet what is causing this disease, but hopefully we can learn from the cautionary tale of the chestnut and try to get out in front of it.

Living Planet Report 2022

WWF’s Living Planet Report is out. They mean this at least in part as a report card on the UN’s “Decade on Biodiversity”, and the grade is a failing one. A few things caught my eye:

  • They have a discussion of “connectivity conservation”, which is intended to reduce fragmentation by connecting protected areas.
  • They determined there is an average 69% global decline in abundance of monitored vertebrate populations between 1970 and 2018. The situation in the tropics is much worse than this average.
  • Populations of corals and sharks in particular are crashing.
  • The “Amazon as we know it” may cease to exist in less than a decade.
  • They give an update on the global ecological footprint from the “National Footprint and Biocapacity Accounts, 2022 edition”. Maybe I’ll have a more detailed look at this another day. The value they give is in hectares per person and I find it hard to interpret given that the population is not constant. They seem most interested in showing that people in more developed countries are using more than their fair share of the planet’s “biocapacity”. Previously, I understood the unit to be the number of planet Earths needed to sustain humanity’s current level of consumption and waste production long-term. A value less than 1 would be sustainable long term, while a value greater than 1 indicates a drawdown of natural capital, creating a debt that will eventually come due.

city biodiversity

This paper in Urban Forestry and Urban Greening suggests three ways to increase biodiversity in cities.

Consideration of the three key factors influencing biodiversity identified here (grassland extent, land-use in the surroundings, and management intensity) would provide the optimal options for maintaining city biodiversity. Protecting current urban grasslands from development and restricting construction in their surroundings, restoring city wilderness areas using urban spatial planning, and setting up butterfly-friendly management regimes (e.g., mowing in mosaic) could all be future options to help enhance biodiversity in cities.

Urban Forestry and Urban Greening

These sound like measures the average U.S. homeowner’s association will gleefully embrace (#irony).

How much ecological function can urban green space provide?

This is an important research question, I think, as the world becomes even more urbanized. Here’s a new study:

Vegetation Type and Age Matter: How to Optimize the Provision of Ecosystem Services in Urban Parks

As cities grow, urban greenspace assumes a more central role in the provision of ecosystem services (ESS). Many ecosystem services depend on the interactions of soil-plant systems, with the quantity and quality of services affected by plant type and age. The question, however, remains whether urban greenspace can be included in the same ecological framework as non-urban greenspace. Our previous studies have contributed towards filling this knowledge gap by investigating the effects of plant functional type (evergreen trees, deciduous trees and lawn) and plant age on soil characteristics and functionality in urban greenspace, offering also a comparison with non-urban greenspace. A total of 41 urban parks and five non-urban forest sites within and adjacent to the cities of Helsinki and Lahti (Finland) were included in this project. Path analyses presented in this contribution, combined with a synthesis of previous findings, offer strong evidence that urban greenspace functions similarly to non-urban greenspace. In particular, plant functional types lead to soil environmental modifications similar to those in non-urban ecosystems. Therefore, vegetation choice upon park construction/implementation can improve the quality and quantity of ESS provided by urban greenspace. However, although vegetation modifies urban greenspace soils with time in a fashion similar to non-urban greenspace, the vegetation type effect is greater in non-urban greenspaces. To conclude, our synthesis of previous studies provides science-based guidance for urban planners who aim to optimize ESS in urban greenspaces.

Urban Forestry and Urban Greening

Ecosystem services and ecological function are not exactly the same thing. Ecological function just is. Ecosystem services are what ecological functions do for people, and fit into the mainstream economic analysis framework. Part of the issue in studying this, I think, is scale. If you look only at one site, block, or park in a city, you might conclude that ecosystems services are negligible or un-measurable. If you look at the entire network and how it is connected, you might conclude that the effects are measurable and that there are policy and design choices that could make them better.

Biodiversity is something else again. More biodiversity is not always better, if it consists of more species of rats or coronaviruses, for example. But biodiversity may be a reasonable proxy measure for how the structure of a designed urban ecosystem translates to ecological function. This is useful if ecological function itself turns out to be difficult to measure. And I think the most useful measures might be biodiversity of animals such as insects (bees, butterflies) and birds. Because the plants in urban areas are mostly the ones that people put there. Biodiversity of plants can be improved through design choices, which is a good thing but in measuring that you are largely measuring inputs to the system rather than the resulting state of the system. Measure the animals, and you are measuring the resulting state of the system.

Measuring things that flit and flutter around might seem daunting. Well, you could try to do it with cameras and image processing of some sort. Or if you are interested in insects you can focus on larva, aka caterpillars. Tracking down bee and wasp nests seems a bit more risky, and you might also have a public relations problem trying to explain why more bee and wasp nests would be a good thing. But caterpillars don’t move fast, so trained people should be able to cordon off an area and find and identify them periodically. Let’s say you did this once a week for a year at several defined points in an urban area, especially if land use changes are occurring (or maybe some places they are occurring and some places they are not occurring.) Doing the same thing in nearby forests and/or farm fields might also add worthwhile data. Now you can do some data analysis and modeling, and maybe figure out design or policy choices that would help the little critters while also benefiting or at least not pissing off people or costing them any money. If you want to fund my half-baked research proposal, let me know.

John Philip Grime

Trends in Ecology and Evolution has an obituary on John Philip Grime, a giant in plant ecology. Not being well educated in plant ecology, I had not heard of him, but I like to learn.

Two seminal publications of the early 1970s would come to define Phil’s approach to finding universal patterns in the structure of vegetation. ‘Competitive exclusion in herbaceous vegetation’ [1.] introduced the ‘hump-backed’ model, which predicted that plant species richness peaks in communities that produce an aboveground biomass of about 600 g m–2 year–1. The model was one of the first to make specific recommendations about the management of local biodiversity. ‘Vegetation classification by reference to strategies’ [2.] introduced ‘competition-stress-disturbance’ (CSR) theory. CSR would become synonymous with Phil’s approach to studying vegetation; because he chose to present the concept as a triangle of three opposing selection pressures, many would come to refer to CSR theory as Grime’s triangle. Although not obvious from these papers, each was based on extensive vegetation datasets of the Sheffield region compiled by the UCPE team (particularly longtime associate John Hodgson). Although many would come to know Phil as a theorist and provocateur (a role he would assume often in the 1980s and 1990s), Phil would always argue that his insights were born of detailed field observations and a UCPE research team with expertise in both field botany and physiology.

Trends in Ecology and Evolution

Biden’s “30 by 30”

According to Yale Climate Connections, “30 by 30” is an ambitious plan to protect 30% of the USA’s land in a natural state by 2030. There is also a less ambitious part of the plan to protect 30% of the USA’s ocean area. I say the ocean part is less ambitious because, according to this article, 26% is already protected. And all you really have to do to protect the ocean (on paper) is draw a box on a map and pass a law saying that box is now protected.

The article refers to E.O. Wilson’s book Half Earth, which argues for protecting…I forget how much of the Earth, I am not good at math. But you get the idea. The moral and rhetorical case here is biodiversity-based, but it’s pretty clear that the practical case is carbon sequestration. There must be a cost-benefit calculation somewhere in there that this is the cheap way to make some progress on blunting the droughts, fires, floods, famines and abandoned coastal cities that are headed our way if we do nothing, and maybe even if we do something but not enough.

Land is different. This article says about 12% is now protected. So how would we actually get to 30? There must be 30% of land out there that is just not legally protected yet.

Achieving 30 by 30 will require action on numerous fronts. “A national program to enact 30 by 30 won’t just be a series of new national parks declared by the President, but will include things like national wildlife refuges, national monuments, state-level protected areas, conservation easements on private land, and co-management with tribal leadership,” wrote marine conservation biologist David Shiffman in Scientific American last October. “Local consultation and support will have to be part of it from the beginning, but it won’t be successful without support and leadership from the federal government.”

And it won’t be enough just to protect any land; it will matter significantly which 30 percent is protected. “Conserving a giant, undeveloped stretch of land where little lives and that no one wanted to develop anyway is not especially helpful to biodiversity conservation or climate resilience,” Shiffman wrote. At least some part of every major ecosystem needs to be protected, he wrote…

More than half of the country’s forests – critical carbon sinks, places that absorb more carbon dioxide than they release – are privately owned. U.C. Berkeley environmental science professors Arthur Middleton and Justin Brashares in the New York Times in December 2020 wrote that “private lands also connect our public lands, providing seasonal habitat for wide-ranging wildlife and clean drinking water, crop pollination, and flood control.” With about 12 percent of the privately land now meeting the 30 by 30 goals, they wrote, protecting the remaining 18 percent “means protecting an area more than twice the size of Texas.”

Yale Climate Connections

For this to be viable, it almost has to be easier than it sounds. I know large private forests are owned by university endowments and other wealthy institutional investors. They can either log them, or they can leave the trees in the ground to get more valuable until they log them later. Or they can sell them, or for all I know buy and sell complicated derivatives based on them. These investors are probably open to the idea of conservation easements which give them an additional payoff in return for agreeing not to develop (i.e. pave or build buildings) the land, which they are probably not interested in doing anyway. This is all speculation on my part.

There’s a lot of farmland out there that farmers would probably be happy to sell for reforestation (or restoration of grassland or wetland habitats) if the government were willing to pay. But I assume we need most of our cropland for growing crops, and taking cropland out of production doesn’t seem like a politically likely solution. Soil conservation is always good, but counting farms engaging in soil conservation practices as “protected natural land” would seem a bit sneaky. If that is what they are thinking, the 30% wouldn’t sound ambitious at all, it would just be a practical common-sense soil conservation program. Again, all speculation on my part. It will be interesting to hear more about this, and interesting to see if the administration can communicate it in a way that avoids conspiracy theories about the government coming for our sacrosanct private property.

diversity and resilience

Here is an example from economics and urban planning of how a diverse system can be a resilient system.

At its peak in 1950, the Coca-Cola bottling plant in Indianapolis employed 250 workers and turned out two million fizz-filled bottles of Coke a week. Now, it is home to the Bottleworks Hotel, the center of a mixed-use development that opened in late 2020 with the hopes of rejuvenating a neighborhood.

The developer of the site, Hendricks Commercial Properties, said the pandemic had shown the value of diversification as a bulwark against shorter building life spans. No one could have predicted that a havoc-wreaking pandemic would make gathering places so unappealing, at least in the short term. But by having a mix of offices, retail, hotel and other uses, the risk for Hendricks is spread out. The Bottleworks development has an eight-screen movie theater, for instance, but also a tech incubator.

New York Times

This is not really the main point of the article, but I think a useful lesson to learn from the pandemic is that mixed-use neighborhoods where people can live, work, shop, study, and recreate seem to have been more resilient. I don’t have data to back this up, and it should be studied, but it is pretty obvious that the central business district in my city has been hard hit. Very few people live there. The office towers normally fill up each morning with thousands (tens or hundreds of thousands?) of suburban train and car commuters. Restaurants and other services are full of these people on weekdays and often close early on weekday evenings and sometimes are closed on the weekend. Hotels and other businesses that are open in the evening serve business travelers, convention goers, and tourists. There is some shopping, but more luxury goods aimed at these tourists and convention goers rather than basic grocery and household goods. So take away the office workers, business travelers, convention goers, and tourists, and the place is empty. Businesses are devastated. Financially, the city depends on wage, sales, and business tax revenues from the central business district to fund its services throughout the rest of the city. So getting more people to live within walking distance of downtown, and having more “normal” businesses that serve normal people there, could make it more resilient.

The same principle applies to natural ecosystems and agricultural systems too. Diversity might make a system a bit less efficient in terms of production, but you have a variety of organisms waiting in the wings to step in and fill functions if a dominant species that used to fill those functions is lost due to disease, disaster or environmental change (or combinations of these.)

I am thinking about this as I read a book called What’s So Good About Biodiversity by Donald Maier. The author has some reasonable points about biologists using the term biodiversity as a sort of lazy shorthand for ecosystem function or specific benefits. But overall, I find the author to someone without an ounce of understanding of how systems function. He literally can’t see the forest for the trees. He also seems to be a person with zero emotional connection to nature, which I find sad and abnormal. I’m going to call him a biopath – like a psychopath, a person who does not have normal emotions toward other people and is not really aware of what those emotions would feel like. I think there is a normal range of strength of emotion people feel about nature, and I accept that for some people the feelings are not all that strong compared to their feelings about, say, constructed environments or manufactured goods. But to feel nothing is not normal, and the 500 pages of verbal diarrhea in Mr. Maier’s book do not make it any more normal. (I haven’t finished the book – perhaps it will get better towards the end, when Mr. Maier promises to explain what “better reasoning about nature’s value” would look like. If the book has a fantastic ending, I promise to come back and sing its praises in this blog.)