Tag Archives: ecology

game of (bee) thrones

Queen bees demand, and receive, absolute loyalty from their hives. When they are nearing the end of their reigns, they try to arrange to keep their family in power and have one of their daughters assume the throne. But that doesn’t always work out and the struggle over succession can be pretty brutal. This might give George R.R. Martin some ideas.

As far as I can tell, my queen died sometime in the spring. Queens typically live for about four or five years, so this caught me by surprise. A new queen, however, is a regular event in the life of a hive. Beekeepers frequently replace their queens every year or two to introduce genetic variety and ensure that the hive has a strong monarch who can lay enough eggs to keep the population up. Bees can also raise their own queen, and when I did an inspection early that spring, I was pleased to see that mine had taken the initiative. Before she died, my old queen must have laid a few fertilized eggs that worker bees raised as replacements. They would have selected six or seven fertilized (female) eggs and fed them only royal jelly. When the first queen hatched, she would have immediately killed any unhatched competition and ideally flown a few mating flights, storing enough semen in her abdomen to spend the rest of her life laying eggs.

While a newborn queen may seem ruthless, the success of a beehive hinges on allegiance to its queen. Though she can mate with an average of 12 different drones, there is only one queen, which makes for a hive of closely related bees. As a new queen begins to produce her own pheromones, the hive slowly aligns with her as the old bees die and new workers hatch. In a sense, the hive is genetically wired to be loyal to the monarchy. If the hive was to raise multiple queens, or if the workers were to start laying eggs, the interests of the population would slowly fracture…

Bees have about 165 pheromone receptors on their antennae and though it’s not entirely clear how workers “decide” what to do and when (the question of agency is still very much up for debate), it is certain that the queen’s pheromones prompt them to go about their business. When the reigning monarch dies or stops laying eggs in her old age, the change in her pheromones prompts the hive to raise a replacement, as my hive had done. Similarly, if a new queen arrives and releases her pheromones before those of the old queen have dispersed, the hive will consider the new queen an invader, and kill her. Above all, they are loyal to their queen. I did not fully grasp this fact. Because I waited only six hours between queens, the worker bees probably stung my new queen to death within an hour.

a prosperous way down

This paragraph caught my eye in the blog A Prosperous Way Down:

The environment is not an element (subsystem) of the economy/finance role-playing game. The economy is actually a subsystem of society, which is embedded in the geobiosphere, its super-system. From a systems perspective, any rearrangement of the geobiosphere as a result of new driving forces, including anthropogenic emissions, affects the behavior, the stability and the sustainability of the global economy as a subsystem. Economically based choices do impact the environment, but the geobiosphere then readjusts its operation (somewhat unpredictably) and impacts the behavior of the global economy itself. Any hope to make significant changes to the global environment (the super-system) while at the same time keeping the operation of our economy fixed or expanding is inconsistent with systems thinking. But this seems to be exactly what people are trying to do, by trying to freeze the current status of the environment as a provider of raw material and ecosystem services that can guarantee economic growth.

If you think about it enough, it becomes fairly obvious that humans are not that different than other animals trying to gain an advantage by exploiting finite energy and other resources in our environment. We are such ingenious exploiters that we have been able to pretend the environment isn’t there, but it seems clear that the environment may finally be catching up with us. Reorienting the principles of economics in an ecological framework seems like an obvious and clear thing to do.

“automated curation of wild places”

This is a fascinating idea, could even be attempted on other planets, and provides limitless ideas for dystopian science fiction about what could go wrong and/or whether we could all be experiencing some form of “automated curation” right now.

Designing Autonomy: Opportunities for New Wildness in the Anthropocene
Bradley Cantrell, Laura J. Martin, and Erle C. Ellis

Maintaining wild places increasingly involves intensive human interventions. Several recent projects use semi-automated mediating technologies to enact conservation and restoration actions, including re-seeding and invasive species eradication. Could a deep-learning system sustain the autonomy of nonhuman ecological processes at designated sites without direct human interventions? We explore here the prospects for automated curation of wild places, as well as the technical and ethical questions that such co-creation poses for ecologists, conservationists, and designers. Our goal is to foster innovative approaches to creating and maintaining the autonomy of evolving ecological systems.

After rooting around just a bit I was able to find an open source proof of this paper here.

wildlife resilience and urban parks

This article suggests that urban parks are not as good as rural reserves for supporting biodiversity, but they can still play a role in improving the resilience of species. Of particular interest to me are some the measures ecologists are coming up with to try to define and measure resilience.

Urban parks can maintain minimal resilience for Neotropical bird communities

Birds may use urban parks as shelter and refuge, contributing with numerous ecosystem services upon which humans and other organisms depend on. To safeguard these services, it is important that bird communities of urban environments hold some degree of resilience, which refers to the capacity of a system to absorb disturbances and changes, while maintaining its functions and structures. Here we assessed the resilience of the bird community inhabiting an urban park in the Southeast region of Brazil. We classified birds in feeding guilds and identified discontinuities and aggregations of body masses (i.e., scales) using hierarchical cluster analysis. We then calculated five resilience indices for our urban park and for a preserved continuous forest (reference area): the average richness of functions, diversity of functions, evenness of functions, and redundancy of functions within- and cross-scale. The urban park had less species, lower feeding guild richness, and lower within-scale redundancy than the reference area. However, they had similar proportion of species in each function, diversity of functions, evenness of functions, and cross-scale redundancy. The lower species richness and, consequently, the lack of some species performing some ecological functions may be responsible for the overall lower resilience in the urban park. Our results suggest that the bird community of the urban park is in part resilient, as it maintained many biological functions, indicating some environmental quality despite the high anthropogenic impacts of this area. We believe that urban forest remnants with more complex and diverse vegetation are possibly more likely to maintain higher resilience in the landscape than open field parks or parks with suppressed or altered vegetation. We propose that raising resilience in the urban park would possibly involve increasing vegetation complexity and heterogeneity, which could increase biodiversity in a large scale.

tipping points and ecosystem collapse

This research presents seagrass meadows as an example of an ecosystem that seems to disappear suddenly, but actually reached a tipping point caused by chronic pollution.

Testing for thresholds of ecosystem collapse in seagrass meadows?

Ecological systems can be dynamic and unpredictable, with shifts from one ecosystem state to another often considered ‘surprising’. This unpredictability is often thought to be due to ecological thresholds, where small cumulative increases in an environmental stressor drives a much greater consequence than would be predicted from linear effects, suggesting an unforeseen tipping point is crossed. In coastal waters, broad-scale seagrass loss often occurs as a sudden event which is associated with human-driven nutrient enrichment (eutrophication). We tested whether the response of seagrass ecosystems to coastal nutrient enrichment represents a threshold effect. Seagrass response did follow a threshold pattern when nutrient enrichment (dissolved inorganic nitrogen) exceeded moderate levels, with a switch from positive to negative net leaf production. Epiphyte load also increased with nutrient enrichment, potentially driving this shift. Inadvertently crossing such thresholds, as can occur through ineffective management of land-derived inputs such as wastewater and stormwater on urbanised coasts, may help account for the widely observed ‘sudden’ loss of seagrass meadows. By identifying tipping points we may not only improve monitoring for adaptive management that seeks to avoid threshold effects, but also the restoration of systems that have crossed them.

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.

What a Fish Knows

What a Fish Knows is what it sounds like – a book about what fish are thinking. From the publisher:

Do fishes think? Do they really have three-second memories? And can they recognize the humans who peer back at them from above the surface of the water? In What a Fish Knows, the myth-busting ethologist Jonathan Balcombe addresses these questions and more, taking us under the sea, through streams and estuaries, and to the other side of the aquarium glass to reveal the surprising capabilities of fishes. Although there are more than thirty thousand species of fish—more than all mammals, birds, reptiles, and amphibians combined—we rarely consider how individual fishes think, feel, and behave. Balcombe upends our assumptions about fishes, portraying them not as unfeeling, dead-eyed feeding machines but as sentient, aware, social, and even Machiavellian—in other words, much like us.

What a Fish Knows draws on the latest science to present a fresh look at these remarkable creatures in all their breathtaking diversity and beauty. Fishes conduct elaborate courtship rituals and develop lifelong bonds with shoalmates. They also plan, hunt cooperatively, use tools, curry favor, deceive one another, and punish wrongdoers. We may imagine that fishes lead simple, fleeting lives—a mode of existence that boils down to a place on the food chain, rote spawning, and lots of aimless swimming. But, as Balcombe demonstrates, the truth is far richer and more complex, worthy of the grandest social novel.

Highlighting breakthrough discoveries from fish enthusiasts and scientists around the world and pondering his own encounters with fishes, Balcombe examines the fascinating means by which fishes gain knowledge of the places they inhabit, from shallow tide pools to the deepest reaches of the ocean.

Teeming with insights and exciting discoveries, What a Fish Knows offers a thoughtful appraisal of our relationships with fishes and inspires us to take a more enlightened view of the planet’s increasingly imperiled marine life. What a Fish Knows will forever change how we see our aquatic cousins—the pet goldfish included.

forests as a carbon source?

This journal article talks about the possibility of a disturbing situation where climate change starts to kill trees, which are then no longer able to absorb carbon dioxide, which causes more climate change, and so on in an accelerating feedback loop.

Trees Can Limit Climate Change—Unless It Kills Them First

Scientists have considered forests a potential barrier to climate change, since plants on land take up about 25 percent of our carbon dioxide emissions. As trees in colder areas are exposed to warmer temperatures and more CO2 emissions, they will grow faster and absorb more emissions, helping to mitigate the effects of a primary greenhouse gas, the theory goes.
But, in an alarming twist, global warming is likelier to limit forests’ capacity for absorbing emissions in many parts of the continent, a study released today in the journal Ecology Letters finds. After combining climate projections with the tree records, researchers found no evidence for the boreal greening hypothesis. In fact, they found a risk of a negative feedback loop, as trees in their model reacted poorly to warmer temperatures due to drought and other disturbances.
That means as trees die faster than they can take up CO2 emissions, releasing trapped carbon, forests could become a net source of carbon, accelerating climate change. The study found that we could reach such a tipping point as early as 2050.

new book on soil

Here’s a review on a new book on soil.

Soils had not excited many ecologists until, two decades ago, soil ecologists started emphasizing that many aboveground phenomena are under belowground control. Richard Bardgett is one of the most eloquent and knowledgeable of the soil scientists who have contributed to the current enthusiasm about soils. In his recent book Earth Matters: How Soil Underlies Civilization he explains how much human societies depend on soil. He writes about how soils are formed, how they influence biodiversity and food quality, and what role they play in cities and in war, and introduces us to the interplay of soils and climate change.