Water Quality Team - Biodiversity for a Livable Climate

Featured Creature: Axolotl

What animal was named after an Aztec god, maintains a youthful appearance for its entire life, and can regrow limbs, organs, and even parts of its central nervous system without scarring?

A leucistic axolotl
(Image credit: John P Clare via Flickr, CC-BY-NC-SA 2.0)

Axolotls happen to be my favorite of all amphibians! Why? They’re just so darn unique (as you’ll find as you read this profile)! I recall seeing my first batch of axolotls when touring a scientific lab in Cambridge, Massachusetts, and I can say without a doubt that they are cuter in-person (especially the hatchlings) than they are through the screen of a computer or television.

But, a laboratory, you say? Today, far more axolotls exist in captivity or in lab environments than in the wild (we’ll get to their hyper-specific range later). Like much of the more-than-human world, the axolotls’ relationship with research environments has been checkered and controversial. Historically, many of the breakthroughs in axolotl regeneration came from invasive lab studies, a reflection of an older scientific mindset that prioritized discovery over care. Today, more researchers (and the rest of us) are asking: ‘how can we learn from nature without harming it?’

Water Dog? Water Monster?! Hardly!

The axolotl is named after the Aztec god of fire, lightning, monstrosities, sickness, and more… Xolotl (English pronunciation: show-LAH-tuhl), who in art was depicted as a dog-headed man, a deformed monster with reversed feet, or a skeleton. According to the creation myth recounted in the Florentine Codex, after the Fifth Sun was initially created, it did not move. Ehecatl (God of Wind, English pronunciation: e-HE-kah-tuhl), consequently began slaying all of the other gods to induce the newly-created Sun into movement. Xolotl, however, was unwilling to die, and among the creatures he transformed himself into in order to avoid capture was an axolotl. In the end, his effort was in vain.

With all of that mythological backstory out of the way, common translations from Nahuatl (the language of the Aztecs) for the axolotl include “water monster” and sometimes “water dog”. Of course, looking at an axolotl, it is obviously not a dog, and CERTAINLY not a monster.

The Peter Pan of Salamanders

No, I didn’t come up with that phrase myself. Numerous sources, including The Nature Conservancy, have compared the axolotl to “The Boy Who Never Grew Up”. Axolotls are members of the salamander family, and salamanders usually undergo a process called metamorphosis to become adults. It’s very much like how a tadpole becomes a frog, replacing their gills for lungs, and moving around on land. One unique feature of the axolotl is that they never undergo metamorphosis. Rather, they keep their frilly external gills and other juvenile features, and remain in the water for their lifetime. Even though they look like the “tadpole” form of most salamanders, they do become adults in the sense that they are able to reproduce, and grow larger compared to when they hatched (typically up to 9–12 inches (23–30 cm)). This condition or characteristic is known as neoteny.

(Image Credit: John P Clare via Flickr, CC-BY-NC-SA 2.0)

A Salamander Superpower

Axolotls are also known for a few other “salamander superpowers,” especially their remarkable ability to regenerate. If a limb, tail, or even part of an organ is lost to injury or predation in the wild, the axolotl simply grows it back, perfectly. Limbs can regenerate multiple times over the course of the axolotl’s life without scarring, and every tissue involved is rebuilt: bone, cartilage, muscle, skin, blood vessels, and nerves. And yes, I said organs too. Limited parts of the heart, lungs, spine, and brain can regenerate as well, and remain fully functional.

While going into detail about just how this regeneration is done would fill a library, from what we know this process starts with a flurry of biological coordination. After an injury, certain skin and muscle cells near the wound site essentially “reset” themselves, reverting to a stem-cell-like state. These cells gather into a small mound called a blastema, not too different from the buds that grow into limbs in a developing embryo. From there, guided by molecular cues from the surrounding tissues, that blastema begins reconstructing the missing part, layer by layer, in perfect proportion and order. Nerves and blood vessels regrow too, restoring full function.

Axolotls are able to do all this without forming scar tissue — a key difference from most other vertebrates. Non-invasive researchers studying regeneration from an ecological perspective believe this may be due in part to the axolotl’s highly tuned immune response, which seems to encourage healing rather than halt it. Perhaps owing to this physiological philosophy, axolotls also appear to be extraordinarily resistant to cancer. Their cells seem to have built-in checks that limit runaway growth even during rapid regeneration. Do the same mechanisms that allow for precise, rapid regeneration also give the axolotl greater control over proliferating cancerous cells?

A Keystone AND Indicator Species

Axolotls are classified as a keystone species–one that plays a crucial role in maintaining the health and diversity of their native ecosystem(s), as their actions significantly impact the environment and other species. What exactly do axolotls do that impacts their local ecosystem and environment? Axolotls are carnivores, by ingesting with a vacuuming-like maneuver (and thus, controlling populations) various small animals, including insects and their larvae, worms, crustaceans, mollusks, and even small fish. By doing so, they keep these populations in check and help to maintain the balance of their aquatic environment.

Axolotls are also an indicator species–one that is particularly responsive to changes in their environment, which can then be used to assess the health of an ecosystem, the quality of a particular habitat, and/or the impact of human activities. In the case of the axolotl, their sensitivity to changes in water quality, temperature, and pollution levels make them a living, breathing, warning system. A decline in populations of axolotls will often signal broader environmental degradation or changes.

Xochimilco on the outskirts of Mexico City is one of the few places axolotls can be found in the wild.
Pablo Leautaud, **CC BY-NC 2.0**

Even Superheroes Need Help

Wild axolotls are found in only two (dwindling) places: Lakes Xochimilco and Chalco in the southern reaches of Mexico City. Though they may be eaten by storks, herons, and large fish from time-to-time, their biggest threats are urbanization and pollution of the lakes in which they live.

Life in the manmade canals of Xochimilco, a once-thriving agroecological system, has put the axolotl on a daily collision course with humans and a more extractive built environment. These waterways were once part of chinampa farming, an ancient, sustainable method that supported both people and native species. But centuries of colonial disruption, urban expansion, and pollution have degraded the ecosystem. Today, most of Xochimilco’s water is too toxic to support native life, and axolotls are left struggling to survive in what was once their ecological stronghold.

Their persistent decline has also been attributed to predation from introduced invasive fish and large birds, as well as overfishing for both food and medicinal purposes. They are currently listed as Critically Endangered by the IUCN Red List. While estimates of the number of mature wild individuals are hard to come by and not always reliable, most sources report between 50-1,000, versus at least a million in captivity.

To save wild populations of axolotls, a species recovery plan needs to involve habitat management and restoration before any other measure, such as further axolotl reintroductions. Any reintroduction efforts should take care to avoid introducing potential diseases or genetic problems from captive colonies to wild ones.

Sienna Weinstein is a wildlife photographer, zoologist, and lifelong advocate for the conservation of wildlife across the globe. She earned her B.S. in Zoology from the University of Vermont, followed by a M.S. degree in Environmental Studies with a concentration in Conservation Biology from Antioch University New England. While earning her Bachelor’s degree, Sienna participated in a study abroad program in South Africa and Eswatini (formerly Swaziland), taking part in fieldwork involving species abundance and diversity in the southern African ecosystem. She is also an official member of the Upsilon Tau chapter of the Beta Beta Beta National Biological Honor Society.

Deciding at the end of her academic career that she wanted to grow her natural creativity and hobby of photography into something more, Sienna dedicated herself to the field of wildlife conservation communication as a means to promote the conservation of wildlife. Her photography has been credited by organizations including The Nature Conservancy, Zoo New England, and the Smithsonian’s National Zoo and Conservation Biology Institute. She was also an invited reviewer of an elephant ethology lesson plan for Picture Perfect STEM Lessons (May 2017) by NSTA Press. Along with writing for Bio4Climate, she is also a volunteer writer for the New England Primate Conservancy. In her free time, she enjoys playing video games, watching wildlife documentaries, photographing nature and wildlife, and posting her work on her LinkedIn profile. She hopes to create a more professional portfolio in the near future.

Dig Deeper

Featured Creature: Rotifers

I’m smaller than dust, yet ancient and wise,
I thrive in the harshest of lows and highest of highs.
No mate, no death, no fear of the cold,
I borrow new genes when my own get too old.

Our world follows certain rules. Or at least, that’s what I was taught growing up. Falling objects accelerate at 9.8 meters per second squared in a vacuum. Warm air rises. Diagonally cut sandwiches just taste better. Living things, too, evolve a certain way, survive a certain way, die a certain way.

Or so I thought, anyway.

I was not taught that there are some creatures out there that cheat death, that rewrite their own DNA and survive in conditions that should render said survival impossible. At a moment when humans are trying to hack biology in an effort to live younger, longer, there are creatures out there that have been doing it for millions of years.

Meet the rotifer.

You’ve probably never seen one, but they’re everywhere: in puddles, moss, soil, and freshwater lakes. They look like something from Pandora, spinning through water with wheel-like cilia. Hardly larger than a speck of dust, they don’t roar, they don’t tower over landscapes, and they’re not exactly at the top of any food chain as I know them. But they’ve outlived entire species, survived mass extinctions, and continue to defy the rules of biology we thought we knew.

While rotifers may be practically invisible to our eyes, their impact is not. They play a fundamental role in freshwater ecosystems, drifting through aquatic environments and feeding on algae, bacteria, and other organic debris. Remember my little quip earlier about food chains? Well, it’s sort of a half-truth. They feed on algae, bacteria, and bits of organic debris—basically whatever’s floating around at the microbial level. In doing so, they turn microscopic life into something usable for everything else. They’re one of the first stops in the food web, sustaining creatures far bigger than themselves. Take them out, and the whole darn thing starts to wobble.

Life is full of exceptions, and even the smallest creatures can upend our understanding of what survival, and life itself, really means.

Rule #1: It Takes Two to Tango

A fundamental principle of biology I thought I understood is that species need genetic diversity to evolve and survive. Sexual reproduction is nature’s way of mixing genes, creating stronger offspring that are better adapted to changing environments. Without this reshuffling of DNA, plant and animal species alike face genetic stagnation and, over time, possibly extinction.

Rotifers see it differently.

For tens of millions of years, the bdelloid class of rotifer has lived without sex. They reproduce by cloning themselves over and over, spawning genetically identical offspring generation after generation.

By my logic, this should have led to their extinction long ago. They should have faced great difficulty adapting to changing environments, vulnerable to disease, and trapped in a state of evolutionary stasis. Instead, they’ve flourished.

But how?

By stealing DNA from other organisms. Instead of relying on traditional sexual reproduction, bdelloid rotifers are actually able to absorb genetic material from bacteria, fungi, and even some plants. This process, known as horizontal gene transfer, allows them to patch together their own genes with foreign DNA, essentially hijacking useful traits from unrelated life forms.

It’s a complicated process that, to be honest, I don’t fully understand. But that’s okay, because neither do the scientists studying this stuff. Here’s what they think is happening.

When a bdelloid rotifer dries out (usually in a harsh environment), its DNA begins to crumble and break apart into pieces. When it rehydrates, something strange happens: its cell walls become more permeable, just enough to let in snippets of DNA floating nearby, bits from bacteria, fungi, even plants. Once inside, the rotifer’s cellular machinery picks them up and patches them into its own fragmented genome. It’s like a genetic repair job using whatever foraged parts are lying around. Instead of mixing genes through sex, bdelloids build their genetic diversity by borrowing from the world around them. It’s a little messy, a little miraculous, but it works.

Rotifers can get nutrients from algae they can’t eat directly. A parasitic fungus infects algae and releases spores, which the rotifers can eat, allowing energy to pass from the algae to the rotifer through the fungus.
Image Credit: Virginia Sánchez Barranco, et al. 2020

Rule #2: Death and Taxes

I remember my parents quipping throughout my childhood that there are only two sure things in this life, death and taxes. But while I can’t speak for their fiduciary responsibilities, rotifers have been able to generally cheat the former.

When an organism is deprived of water, it usually dies. Cells shrivel, biological processes shut down, and life ends.

When conditions turn hostile for rotifers, when droughts dry up their ponds, when ice encases them, when the world around them becomes unlivable, rotifers don’t really die. They shut down, entering a sort of paused or stalled state, called cryptobiosis. Their bodies lose nearly all water content, their metabolism grinds to a halt, and for all practical purposes, they are lifeless husks of a microorganism. But give them a single drop of water, and they wake up, pretty much just as they were before.

Some rotifers can survive in this suspended animation for decades. Others have gone far longer. In one of the most staggering discoveries, scientists revived a 24,000-year-old rotifer from Siberian permafrost, and it immediately resumed life, eating, cloning itself, and otherwise carrying on as if it had just taken a nap. I’m not too well-versed on Marvel films, but I’m 99% sure this was basically the plot of a Captain America movie.

Most creatures don’t get a second chance at life, and this individual superpower bodes well for the species as a whole. Limited though it may be, fossil evidence suggests they’ve been around for tens of millions of years, enduring planetary shifts, ice ages, and environmental catastrophes that wiped out far larger and more powerful creatures. I think it’s safe to say they’re well positioned for another few dozen million years, come what may.

notholca rotifer
image credit: Wiedehopf20

The Things We Think We Know

Rotifers challenge what I thought I knew about survival itself. They don’t evolve the way they should, they don’t die when they should, and they have little regard for the biological limits we assume all creatures must adhere to.

Despite their microscopic size, rotifers keep ecosystems running, breaking down organic material, cycling nutrients, and supporting food webs that stretch far beyond their little dominion.

Science is full of rules. They help us understand how the world works. But rotifers are proof that rules aren’t always as rigid as we think. They remind me that life’s possibilities are bigger, weirder, and more resilient than we might imagine.

Brendan Kelly began his career teaching conservation education programs at the Columbus Zoo and Aquarium. He is interested in how the intersection of informal education, mass communications and marketing can be retooled to drive relatable, accessible climate action. While he loves all ecosystems equally, he is admittedly partial to those in the alpine.

Dive Deeper

Featured Creature: ‘Ōhi’a Lehua

What tree has adapted to grow directly in lava rock and is a keystone species of the Hawaiian watershed?

‘Ōhi’a Lehua (Metrosideros polymorpha)!

Image Credit: Kevin Faccenda via iNaturalist

The first time I saw the vibrant blossoms of the ‘ōhi’a lehua tree, I was walking on a dirt path in Kauai’s Waimea Canyon State Park, gaping down at the most colorful red and green gorges I had ever seen. Needing a breather from the steep visual plunge, I looked up from the canyon and noticed bright red flowers on the side of the path. As I got closer and could see the plant more clearly, the first thought that popped into my head was how similar the flowers looked to those fiber optic light toys I had played with as a kid. (If you don’t know what fiber optic light toys look like, look them up. You’ll see exactly what I mean.)

After my trip to Waimea Canyon, I saw ‘ōhi’a lehua everywhere. When I drove along the coast between the beach and the sloping mountains, when I hiked the volcanic craters of Haleakala, and when I visited parks and gardens across the islands that protect native plants and animals. ‘Ōhi’a lehua is the most common native tree in Hawaii, so seeing its fiery red, orange, or yellow blossoms every day felt so very ordinary. But ‘ōhi’a lehua is far from ordinary.

Image Credit: Ed Sharron via iNaturalist

Let Me Introduce You to My New Friend, ‘Ōhia Lehua

Endemic to the six largest islands of Hawaii, ‘ōhi’a lehua is the dominant tree species in native forests, present in approximately 80% of the total area of these ecosystems and covering close to one million acres of land across the state. Depending on where exactly it grows, its size can vary widely, from a small shrub to a large tree. Found only in the Hawaiian archipelago, ‘ōhi’a lehua grows at elevations from sea level to higher than 9000 feet, and in a variety of habitats like shrublands, mesic forests (forests that receive a moderate amount of moisture throughout the year), and more wet, or hydric, forests.

You can easily identify the ‘ōhi’a lehua blossoms by their mass of stamens – the part of the flower that produces pollen – which are slender stalks with pollen-bearing anthers on the end. It’s what made me think the ‘ōhi’a lehua looked exactly like those fiber optic light toys. These powder puff-like flowers are most often brilliant shades of red and orange, but yellow, pink, and sometimes even white ones can be found.

‘Ōhi’a lehua grows slowly, reaching up to 20-25 meters (66-82 feet) in certain conditions.

With a little help from the wind, the seeds of ‘ōhi’a lehua travel from the tree and settle in cracks in the ground of young lava rock. It is, in every sense, a true pioneer plant. As one of the earliest plants to colonize and grow in fresh lava fields, ‘ōhi’a lehua stabilizes the soil and makes it more habitable for other species.

Even though ‘ōhi’a lehua can blanket Hawaii’s native forests, this flowering tree also grows alone, as you can see in the photograph below. Plants like ‘ōhi’a lehua fill me with happiness because they are able to grow in the most harsh, barren, and disrupted places, and they make it possible for other species to do the same. Plants like ‘ōhi’a lehua fill me with surety that even though sometimes poorly treated, the natural world will continue to be strong. Plants like ‘ōhi’a lehua make me believe in the resilience of nature.

Arid, rocky, Mediterranean coast. (Via Pexels)

How ‘Ōhi’a Lehua Cares for the Hawaiian People

Biodiversity forms the web of life we depend on for so many things – food, water, medicine, a stable climate, and more. But this connection between human beings and natural life is not always clear, understood, or appreciated. But there is a concept in Hawaiian culture called aloha ‘āina, or love of the land, which teaches that if you take care of the land, it will take care of you. The ‘ōhi’a lehua in particular takes care of the Hawaiian people in a pretty special way.

One of the most important characteristics of this flowering evergreen tree is that it’s a keystone species, protecting the Hawaiian watershed and conserving a great amount of water. The way I see it, ‘Ōhi’a lehua is an essential glue that holds Hawaii’s native ecosystems together. The leaves of ‘ōhi’a lehua are excellent at catching fog, mist, and rain, replenishing the islands’ aquifers and providing drinking and irrigation water for Hawaiian communities. ‘Ōhi’a lehua’s ability to retain water, particularly after storms, not only makes that water accessible for other plants, but it helps mitigate erosion and flooding. The tree provides food and shelter for native insects, rare native tree snails (kāhuli), and native and endangered birds like the Hawaiian honeycreepers (‘i’iwi, ‘apapane, and ‘ākepa). ‘Ōhi’a lehua trunks protect native seedlings and act as nurse logs, providing new plants with nutrients and a growing environment.

‘I’iwi, the Scarlet Hawaiian Honeycreeper, perched on an ‘ohi’a tree (Image Credit: Nick Volpe)

The Myth of ‘Ōhi’a Lehua

‘Ōhi’a lehua may have a disproportionately large effect on Hawaii’s ecosystems as a keystone species, but its presence as a meaningful part of Hawaiian culture could be even larger. There are many versions of mo’olelo (story) about the origin of the ‘ōhi’a lehua tree, but the most common one is about young lovers named Ōhi’a and Lehua. Pele, the goddess of the volcano, changed herself into a human woman and tried to entice ‘Ōhi’a. When he denied her, Pele became enraged and transformed ‘Ōhi’a into a tree. When Lehua found out, she was so heartbroken that she prayed to the gods to somehow help her reunite with him. Answering her prayers, the gods transformed Lehua into a flower and placed her on the ‘ōhi’a tree’s limbs. To this day, it’s believed that whenever a lehua flower is picked, the skies will open up and rain will fall, because the lovers have been separated.

‘Ōhi’a Lehua as a Cultural Symbol

In Hawaiian culture, the ‘ōhi’a lehua is a symbol of love, resilience, and ecological harmony. The transformation of Ohia and Lehua into tree and flower represents the inseparable bond between two people who love each other, and between the tree and its flowers. The term pua lehua, or lehua flowers, is often used to describe people who express the same grace, strength, and resilience of the ‘ōhi’a lehua. Pilina, a Hawaiian word that means “connection” or “relationship,” is an important value in Hawaiian culture because it is a critical way for people to connect with and understand the world around them. The ‘ōhi’a lehua tree is a symbol of pilina, and embodies this relationship between the Hawaiian landscape and its people.

Hula dancers performing at the Merrie Monarch Festival
Thomas Tunsch (**CC BY-SA** )

The ‘ōhi’a lehua is also incredibly important to hula. Hula is the narrative dance of the Hawaiian Islands, and it is an embodiment of one’s surroundings. Dancers use fluid and graceful movements to manifest what they see around them and tell stories about the plants, animals, elements, and stars. ‘Ōhi’a lehua trees and forests are considered sacred to both Pele, the goddess of the volcano as you may recall, and Laka, goddess of hula. To enhance their storytelling and evoke the gods, dancers traditionally wear lehua blossoms or buds in lei, headbands, and around their wrists and ankles.

The Dependability of ‘Ōhi’a Lehua

‘Ōhi’a lehua has long been a part of daily life. Historically, the hardwood of the tree was used for kapa (cloth) beaters, papa ku’i ‘ai (poi pounding boards), dancing sticks and ki’i (statues), weapons, canoes, and in the construction of houses and temples. Today, the tree’s wood is used for flooring, furniture, fencing, decoration, carving, and firewood. ‘Ōhi’a lehua blossoms decorate altars for cultural ceremonies and practices. Flowers, buds, seeds, and leaves form the base of medicinal teas that can stimulate appetite and treat childbirth pain.

Threats to ‘Ōhi’a Lehua

As a native tree, ‘ōhi’a lehua competes with invasive species for moisture, nutrients, light, and space. Plants like the strawberry guava plant (Psidium cattleyanum) grow in dense thickets and block the growth of ‘ōhi’a seedlings. The invasive fountain grass (Pennisetum setaceum) can dominate barren lava flows, making it difficult for ‘ōhi’a to compete. ‘Ōhi’a lehua is also threatened by non-native animals. Hooved animals like pigs, cattle, goats, and deer disturb the soil, eat sensitive native plants, and trample the roots of ‘ōhi’a lehua trees.

The most dangerous threat to ‘ōhi’a lehua is a virulent fungus called Ceratocystis fimbriate, which attacks the tree’s sapwood, preventing it from uptaking water and nutrients, and killing the tree within weeks. It’s been given the name Rapid Ohia Death (ROD) because of how quickly it suffocates the tree, turning the leaves yellow and brown and the sapwood black with fungus. Infections spread through a wound in the bark, which can be caused by animals trampling roots, lawn mowing, or even pruning, and can be present in the tree for up to a year before showing symptoms. ROD is spread by an invasive species of wood boring Ambrosia beetle that infests the tree and feeds off the fungus. When colonizing trees, the beetle produces a sawdust-like substance made of excrement and wood particles called frass, which can contain living fungal spores that get carried in wind currents and spread by sticking to animals and human clothes, tools, and vehicles.

Since its discovery in 2014, ROD has killed more than one million ‘ōhi’a lehua trees across 270,000 acres of land, making it a significant threat to biodiversity and cultural heritage. The International Union for Conservation of Nature (IUCN) classifies ‘ōhi’a lehua’s conservation status as vulnerable, and has recorded a decline in mature trees since 2020. Because ROD can spread long distances, it has the potential to wipe out ‘ōhi’a lehua across the entire state. If ‘ōhi’a lehua disappears, it will lead to a collapse of the Hawaiian watershed and radically change the ecosystem.

How the Hawaiian People Care for ‘Ōhi’a Lehua

Scientists, researchers, and native Hawaiians are working together to ensure the long-term health and resilience of ‘ōhi’a and Hawaii’s native forests by mitigating the spread of Rapid Ohia Death. Hawaii’s Forest Service monitors the land to track the spread of ROD and mortality of trees, has developed sanitation and wound-sealing treatments, and collaborates with hunters and game managers to reduce disease transmission. Scientists rigorously test ‘ōhi’a trees to understand the disease cycle, find out how it can be broken, and to identify trees resistant to the infection that could be used in potential reforestation efforts.

To prevent the spread, Hawaii has announced quarantine restrictions, travel alerts, and sanitation rules. If you are shipping vehicles between islands, you should clean the entire understory with strong soap to remove all mud and dirt from the tires and wheel wells. People who go into ‘ōhi’a forests are advised to avoid breaking branches or moving wood around, to clean their shoes and clothes, and to decontaminate any tools used with alcohol or bleach to kill the fungus. Even hula practitioners are forgoing the use of ‘ōhi’a lehua.

Orange ‘ōhi’a lehua blossom (Image Credit: Joan Wasser via National Park Service)

Mālama the ‘āina

Mālama the ‘āina is a phrase that means to care for and honor the land. ‘Ōhi’a lehua is a wonderful representation of the interconnection between people and nature and I hope learning about this beautiful tree has encouraged you to appreciate the relationship we have with the Earth and what the natural world does for us.

Remember, if you take care of the land, it will take care of you.

Abigail

Abigail Gipson is an environmental advocate with a bachelor’s degree in humanitarian studies from Fordham University. Working to protect the natural world and its inhabitants, Abigail is specifically interested in environmental protection, ecosystem-based adaptation, and the intersection of climate change with human rights and animal welfare. She loves autumn, reading, and gardening.

Sources and Further Reading:

Featured Creature: Sphagnum moss

What bog-builder can hold 15-20 times its dry weight in water?
Sphagnum moss!

by David McNicholas

The distinctive brown color of Sphagnum beothuk forming a large hummock on a raised bog. (Photo courtesy David McNicholas)

As an ecologist working on Ireland’s peatland restoration, I’ve seen firsthand the profound transformation of re-wetting former industrial peatlands, and its capacity to enhance biodiversity and carbon storage. Working as a member of the Bord na Móna Ecology Team with funding provided by the EU’s Recovery and Resilience Facility as part of Ireland’s National Recovery and Resilience Plan, I’ve have seen more than 60 peatland sites undergo this incredible transformation. Following extensive ecological, hydrological and engineering studies to create the optimal conditions for Sphagnum moss establishment, it is exciting to now move towards the active planting of Sphagnum moss back onto these peatlands. This will accelerate the establishment of Sphagnum-rich bog vegetation that will have greater biodiversity and climate benefits at scale.

Raised bog formation

Sphagnum moss species are key plants in the development and existence of bog habitats. Some species can hold 15 to 20 times their dry weight in absorbed water and tolerate very harsh conditions such as nutrient deficiency, high acidity and waterlogged environments. This ability of Sphagnum to hold water creates the quaky surface conditions that are characteristic of raised bogs in good condition. Bogs simply would not exist as we know them without Sphagnum.

Raised bogs begin to develop in wet shallow depressions, often shallow lakes. Over time, wetland vegetation such as reeds, rushes and other plants leave dead matter behind in the substrate. As the amount of dead vegetation accumulates, the layer of growing vegetation on top is eventually lifted above the influence of the local groundwater. At this point, this layer has become ombrotrophic (exclusively rain fed). The result, in wetter climates, is the development of a wet, nutrient poor and acidic environment in which Sphagnum species thrive. Sphagnum is known as an “ecosystem engineer”. This moss can change its environment, making it wetter and more acidic, suiting these mosses and creating perfect peat-forming raised bog. As the living plants grow upward, the Sphagnum tissue beneath the living surface of the bog is submerged beneath the weight of the growing layer above. This dead material does not completely decay in the anoxic, waterlogged conditions. Instead, it will become peat over time, while the living material will continue to grow, driving the formation of a raised bog dome.

*Sphagnum cuspidatum* occurring within a bog pool. This species occurs in pools and the wettest parts of peatlands. (Photo courtesy David McNicholas)

Sphagnum’s role in carbon sequestration

The growth habit of Sphagnum is directly responsible for the development of one of nature’s most efficient carbon traps. A metre squared of intact, good quality raised bog sequesters a small amount of carbon annually, but over time these peatlands can accumulate and store much more carbon than the same area of other ecosystems like tropical rainforest. As such, Sphagnum moss is very important to help tackle climate change by taking in carbon and by creating peat-forming conditions to secure this carbon in the ground within healthy peatlands.

The ability of Sphagnum to store water also plays an important role in regulating heavy rainfall events within a catchment. Healthy peatlands can store water in Sphagnum moss, then slowly release this water over time, thereby helping to mitigate potential downstream impacts associated with sudden heavy rainfall.

*Sphagnum* papillosum, with round leaved sundew growing on top. (Photo courtesy David McNicholas)

Sphagnum as an indicator species

Different Sphagnum species can be used as valuable indicators of peatland type and their overall condition. However, Sphagnum mosses are widely believed to be tricky to identify and so many ecologists simply aggregate them, classifying them as “Sphagnum species”. In doing so, ecologists are forfeiting valuable information on nutrient availability, hydrology and habitat condition that these species provide. Like any other plant group, there are generalist and specialist Sphagnum species. For example, Sphagnum rubellum can be found on nearly any bog habitat in Ireland. Small red cushions and hummocks can be found from relatively dry cutover bog to the wettest parts of an active raised bog.

Sphagnum beothuk has a very characteristic chocolate brown colouring and is one of the prettiest raised bog species. While S. austinii has a range of colours, the large size of the individual capitulums (the top of the plant) and the relative compactness of the hummocks as a whole can be used to reliably identify the species. Both species generally inhabit the wetter parts of a bog and if abundant and healthy, can be used as an indicator of raised bogs in good condition. Sphagnum cuspidatum is one of the most aquatic species and is generally found in the acidic bog pools in the wettest parts of the bog. Interestingly, it can be found within the drainage ditches of industrially harvested bogs where no other Sphagnum species may be present. There are some Sphagnum mosses that are found in less acidic and more nutrient rich, fen conditions. To get to know Sphagnum species is to open a large encyclopaedia on the various natural history processes and conditions of our peatlands. However, don’t be put off getting to know the more readily identifiable species and build on this. Knowing just a few species can really add to the satisfaction of exploring our unique peatlands.

**Use of Sphagnum moss in peatland restoration**

Planting Sphagnum moss across re-wetted cutaway bog as a rehabilitation technique is a key objective of the Peatlands and People LIFE Integrated Project (IP). We’re on track to plant one million Sphagnum plugs across over 270 hectares of rehabilitated peatland by November 2024, with ambitious plans for further planting in 2025 and beyond.

Revegetating these areas provides new and more resilient habitat over the longer term. Sphagnum moss will recolonise these sites naturally in time; however, the work we’re doing aims to speed up this trajectory, and we’re establishing a network of peatland sites to develop best practices in restoration and rehabilitation. This involves the design of robust methodologies to monitor and analyse Sphagnum and carbon storage.

While monitoring is ongoing and we have a lot of research ahead of us, initial evaluations of the planted Sphagnum material is already showing positive survival and growth rates.

As I continue my work with Bord na Móna, we’re grateful for the support provided by the European Union’s Recovery and Resilience Facility as part of Ireland’s National Recovery and Resilience Plan, a key instrument at the heart of NextGenerationEU. The primary aim of this scheme is to optimize climate action benefits of rewetting the former industrial peat production areas by creating soggy peatland conditions that will allow compatible peatland habitats to redevelop.

David McNicholas is an Ecologist at Bord na Móna where he works with a multidisciplinary team to deliver an ambitious peatland restoration programme, post-industrial peat production. As a member of the Bord na Móna Ecology Team, David is involved in rehabilitation planning and implementation, while also planning and undertaking monitoring and protected species surveys.

Sources and Further Reading:

Featured Creature: Beaver

Photo by Derek Otway on Unsplash

Which creature fights fires, creates wetlands, recharges groundwater, alters landscapes, and is a climate hero?

Beavers!

At Bio4Climate, we LOVE beavers. We’re borderline obsessed with them (or maybe not so borderline) because they do SO much for Earth’s ecosystems, natural cycles, and biodiversity. These furry, water-loving creatures are finally beginning to receive the recognition they deserve in mainstream media now that more people see how their existence and behaviors lead to numerous benefits for everyone’s climate resilience.

We are one of the many organizations advocating for their reintroduction across North America and some places in Europe. For this reason, when I spotted one on a hike during my time in Tennessee, I did what any Bio4Climate team member would do: jump in excitement, yell out “Oh my gosh it’s a BEAVER!” and take a picture that I’ll treasure forever.

The rockin’ rodent

Beavers live in family groups of up to eight members. Offspring stay with their parents for up to two years, meanwhile helping with newborns, food gathering, and dam building. To create dams, beavers use their large teeth to cut down trees and lug over branches, rocks, and mud until they successfully slow down the flow of water. These dams include lodges that beavers use as bedrooms and to escape from predators. Dams are designed according to the water’s speed: in steady water, the dam is built straight across, and in rushing water the dam is built with a curve. These engineers build their dams in a way that makes them nearly indestructible against storms, fires, and floods.

Look at those bright orange teeth! The color is thanks to an iron-rich protective coating. Beaver teeth grow continuously, and require gnawing on trees for trimming.

Furry firefighters

Beaver dams are what make these rodents, the largest ones in North America, so special. When dams alter the flow of water, they create ponds that stretch out a river into a wide wetland. These ponds filter pollutants and store nutrients that then attract a variety of wildlife including fish seeking nurseries, amphibians looking for shelter, and mammals and birds searching for food and water sources.

The abundance of wildlife and the storage of necessary nutrients in beaver ponds classifies these places as biodiversity hotspots, meaning they are “biogeographic regions with significant levels of biodiversity that are threatened by human habitation” (Wikipedia). Beaver ponds also store sediment, and this helps recharge groundwater. Due to the sheer wetness of these ponds, and how deep the water filters into the soil, fires are often extinguished as soon as they reach a beaver pond. In this way, beavers are nature’s firefighters, of which we need many more in areas where extreme heat is increasing.

“There’s a beaver for that”
— Ben Goldfarb

Wetland Creation
Biodiversity Support
Water Filtration
Erosion Control
Wildlife Habitat

Flood Management
Drought Resilience
Forest Fire Prevention
Carbon Sequestration
They’re Cool (pun intended)

Beavers are considered ‘ecosystem engineers’ because they actively shift the landscape by fluctuating the flow of water and the placement of plants and trees. Muskrats, minks, and river otters also find refuge in beaver lodges. When beavers take down trees, they create pockets of refuge for insects. Using their constructive talents, beavers significantly modify the region and, in turn, create much-needed habitat for many. Numerous creatures rely on beaver dams for survival, and the local ecosystem dramatically changes when a beaver family is exterminated; for these reasons, we also consider them ‘keystone species.’

Disliked dam builders

Despite the positive impact beavers have on biodiversity and ecosystems, we humans have viewed them as fur, pests, and perfume. By 1900, beavers went nearly extinct across Europe and North America. We hunted them for their fur in response to fashion trends, and trapped them for their anal musk glands, or castors, which produce castoreum, a secretion that beavers use to mark their homes and that humans use to make perfume. When beaver populations plummeted, so did the number of dams and ponds, meaning vast swaths of land were drastically altered during this time – and not for the better. To this day, we kill beavers when they wander into military bases or near urban areas since we see their dam-building behaviors as potentially damaging to man-made properties.

Thankfully, as more ‘Beaver Believers’ speak out against these practices and more authorities recognize the importance of beaver benefits, these rodents are beginning to return to their original homes. California recently passed a program specifically for beaver reintroduction efforts across the state. Washington, Utah, and Massachusetts are other states witnessing the return of beavers. People like Skip Lisle of Beaver Deceivers are designing culverts that prevent beaver dams from damaging infrastructure, but allow the beavers to create their biodiverse-filled ponds. These are just a few examples of the ways we can coexist with beavers, and in turn heal our communities.

Beaver Dam on Gurnsey Creek commons.wikimedia.org

Climate heroes

There are places in North America where water sources are decreasing for all living things, and in other regions the amount of rainfall is increasing while the amount of snow is decreasing. These weather conditions are detrimental to all of our health, unless we welcome back beavers.

As the effects of climate change and biodiversity loss increase, storing water, preventing runoff and erosion, and protecting biodiverse hotspots become more important by the hour. By restoring local water cycles, beaver ponds provide a source of life. By spreading water channels and creating new ones, beaver dams prevent flooding and stave off wildfires. By encouraging the cycling and storage of nutrients, beaver ponds nurture soil health and that leads to carbon sequestration. We all have something to gain from beavers as long as we allow them to do what they do best: build those dams.

To learn more about beavers, watch the video below and the two in the ‘Sources’ section. We also highly recommend Ben Goldfarb’s Eager: The Surprising Secret Life of Beavers and Why They Matter for further reading.

For all creatures that deserve a feature,

By Tania Roa

Sources:
Why BEAVERS Are The Smartest Thing In Fur Pants
Why beavers matter as the planet heats up
9 Amazing Beaver Facts
Environmental Benefits of Beavers – King County
8 Facts to Celebrate International Beaver Day | Smithsonian’s National Zoo

Featured Creature: Giant Barrel Sponge

What creature grows tall and sturdy, cleans up its neighborhood, and defends itself from predators – all without moving a muscle?

The Giant Barrel Sponge, or Xestospongia muta!

Photo By Twilight Zone Expedition Team 2007, NOAA-OE – NOAA Photo Library (Public Domain, via Wikimedia Commons)

A Giant Barrel by any other name…

Giant barrel sponges are aptly named for their shape and great size. They grow over 1 m tall, but only grow an average of about 1.5 cm a year. After all, good things take time!

Giant barrel sponges come in a range of colors, depending on the presence of the cyanobacteria that they work with in symbiosis. They can be pink, purple, brown, reddish brown, and gray, and tend to be different colors at different depths.

You may be wondering why this “giant barrel” doesn’t look very much like Spongebob Squarepants, or the sponge you use to clean up in the kitchen. Well sponges, or animals of the phylum Porifera, come in all shapes and sizes, and there is great diversity among the 8,550 species of them. Sponges are quite ancient, with their oldest fossil records dating back 600 million years, so they’ve had time to differentiate and find their own ecological niches.

The giant barrel sponge is known as the “Redwood of the Sea.” The phrase comes from the fact that giant barrel sponges share the tendency for individuals to live long lives, from a few hundred to thousands of years old. In fact, the oldest known giant barrel sponge is over 2000 years old.

Old age isn’t the only thing they have in common with their counterparts on land. Like the magnificent redwoods, they do wonders to clean up and support the environment around them. Giant barrel sponges can filter up to 50,000 times their own volume in water in a single day. They also provide habitat to several small fish and other invertebrates that can be found living inside or on the surface of the sponge.

Photo by Andre Oortgijs (CC BY-SA 3.0 via Wikimedia Commons)

How does such a giant creature sustain itself?

Although giant barrel sponges are, well, giant, their diet is anything but. These creatures, like many species of whales, sustain their size not by eating very large sources of food, but by eating large volumes of it. Giant barrel sponges are filter feeders, and consume microorganisms from the water around them that they pump through their bodies. The sponges have special cells along their inner cavities called choanocytes, which work to facilitate the movement of water and the capture of food from it.

In their ocean food chain, giant barrel sponges take their place above their symbiotic partners cyanobacteria, and are consumed in turn by macroorganisms like fishes, turtles, and sea urchin. They try to defend themselves by releasing chemicals to repel their predators, but there’s only so much they can do when stuck in one place, waiting to be ingested by so many types of marine life. Like other filter feeders, giant barrel sponges ultimately form an important branch in the transfer of nutrients from very small to much larger life forms.

They don’t even have tissues, let alone organs, but their simple structure is more than enough to ensure their survival and proliferation. Giant barrel sponges reproduce by spawning, and are one of the few species of sponge that undertake sexual reproduction. Males and females release sperm and egg cells into the ocean synchronously, so that when the time comes, they have a chance of contributing to a fertilized egg that grows into a larva and, after being carried by currents to a new spot of the ocean floor, establishes itself as an independent sponge.

Check out this short video of the spawning phenomenon:

A valued community member

Giant barrel sponges are native to the oceans of the Americas, found primarily in the Caribbean Sea, and observed as far south as the coasts of Venezuela.

Due to their filtration capabilities, giant barrel sponges are real assets to the ecosystems they are a part of, but boosting water quality is not the only ecological role they play. As mentioned, many other creatures live in and around the cavernous sponges, and giant barrel sponges are one of the largest organisms in the coral reef environments where they are found. They are thought to help coral anchor to substrate (the mix of mineral, rock, and skeleton that binds reefs together), and themselves make up about 9% of coral reef substrate in certain areas where they are found. By helping in this binding process, giant barrel sponges can play an important role in reef regeneration.

Though the giant barrel sponge is not currently classified as threatened, like all of us, it is living in vulnerable times, as reef habitats are weakened in warming, acidifying waters. It is susceptible to a disease called Sponge Orange Band disease that afflicts all kinds of sponges. They can also be damaged or killed by human activities that disturb reefs and break sponges off from their surroundings.

On the flip side, when these great creatures are doing well, they enable the thriving of life all around them. May all of us aspire to say the same.

With one giant smile,
Maya

Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

Sources and Further Reading:
https://animaldiversity.org/accounts/Xestospongia_muta
https://oceana.org/marine-life/corals-and-other-invertebrates/giant-barrel-sponge
https://en.wikipedia.org/wiki/Giant_barrel_sponge
https://www.americanoceans.org/species/giant-barrel-sponge
https://oceanservice.noaa.gov/facts/sponge.html

Featured Creature: Dragonfly

Which creature existed before the dinosaurs, is an aerial genius, and can detect things we can only witness through slow-motion cameras?

The dragonfly!

Eugene Zelenko (CC BY-SA 4.0 via Wikimedia Commons)

Predecessors to the Dinosaurs

Dragonflies were some of the first winged insects to evolve, about 300 million years ago. When they first evolved, their wingspans measured up to two feet! In contrast, today’s dragonflies have wingspans of about two to five inches.

Although in this feature we speak of dragonflies in a general sense, there are more than 5,000 known species of them, each with its own characteristics.

Joi Ito (CC BY 2.0 via Wikimedia Commons)

The Dramatic Entrance

Dragonflies begin as larvae. During this almost 2-year stage, they live in wetlands such as lakes or ponds across every continent except Antarctica. Despite their small size, their appetite is huge, and they are not picky eaters. In their larval to nymph stages, they will eat anything they can grasp including tadpoles, other insect larvae, small fish, mosquitos, and even other dragonfly larvae.

After their nymph stage, dragonflies emerge as if they were reviving from the dead. They crawl out of the water, split open their body along their abdomen, and reveal their four wings- along with their new identity. Then, they spend hours to days drying themselves before they can take to the skies as the insects we know and love.

Once a dragonfly is dry and ready to fly, their voracious appetite continues. As usual, they’ll eat almost anything, but now they will only eat what they catch mid-flight. These feasts consist of butterflies, moths, bees, mosquitoes, midges, and, yet again, even other dragonflies. They seem to embrace the motto “every fly for themself.”

Check out their dramatic transformation:

Engineered for Optimal Flight

Dragonflies emerge after their larval stage as masters of the air. Their four independently moving wings and their long, thin bodies help them maneuver the skies. They hunt and mate in mid-air and they can fly up to 60 miles per hour. They are also able to fly backwards, sideways, and every which way in a matter of seconds or less.

This incredible ability requires excellent vision. (Or else we would likely see them crash much more often!) Thankfully, dragonflies have just the answer. Their head mostly consists of their eyes. Their multiple lenses allow them to see nearly everything around them, covering every angle except one: right behind them. The insect’s vision not only reaches far and wide, but allows them to see the world at faster speeds than we can.

How are human activities impacting dragonflies?

Since dragonflies consume a variety of organisms, and rely on healthy bodies of water to grow, they are considered important environmental indicators. In other words, when dragonfly populations plummet, conservationists have something to worry about. Nymphs and dragonflies will eat just about anything, so they will only go hungry if there is no available food. Looks like those big appetites came in handy after all.

Declines in dragonfly populations also indicate water pollution and habitat loss. These are consequences of agricultural methods that favor chemicals and synthetic fertilizers, and forest management that disregards the importance of maintaining balance within an ecosystem. One solution is regenerative agriculture which ensures fewer toxins in our environment.

Overall, the more green (and blue) space for wildlife, the more likely these iconic insects will thrive.

Tania graduated from Tufts University with a Master of Science in Animals and Public Policy. Her academic research projects focused on wildlife conservation efforts, and the impacts that human activities have on wild habitats. As a writer and activist, Tania emphasizes the connections between planet, human, and animal health. She is a co-founder of the podcast Closing the Gap, and works on outreach and communications for Sustainable Harvest International. She loves hiking, snorkeling, and advocating for social justice.

Featured Creature: Pacific Salmon

This week we ask,

What creatures navigate oceans, climb mountains, feed forests, and motivate us to destroy renewable energy infrastructure?

The Pacific Salmon!

USEPA Environmental Protection Agency (Public Domain via Wikimedia Commons)

How do salmon find their way home?

Pacific salmon are famous for their migrations from the saltwater habitats they live in as mature adults to the freshwater rivers and streams where they were born and return to spawn. Salmon have two means of finding their way back to where they first hatched, often to the very same patch of gravel.

In the open ocean, they have a GPS system based on the earth’s magnetic fields sensed through their lateral line (a highly-sensitive line of nerves running down each side of their bodies). When they get near shore, they then follow smells that they imprinted from their natal river up to where they originally hatched, to spawn again and continue this cycle.

How do salmon manage to get back upstream?

Salmon make their way back home against the current of streams and rivers, even climbing mountains in the process. As they go, they feed upland forests by transporting ocean nutrients into the headwaters of their natal streams, supporting all kinds of life in the process (and not just hungry bears)!

Istvan Banyai (CC BY-SA 3.0 via Wikimedia Commons)

What happens to Pacific salmon after they successfully spawn?

Spawned-out Pacific salmon all die after completing their journey. In late fall, on a salmon river, rotting corpses and dying fish appear everywhere, white with mold and stinking with decay. In doing so, they feed forests and the aquatic life that sustains the next generation of fish when they hatch in the spring. We don’t really know why they all die after spawning, unlike the Atlantic salmon, which live after the process is complete.

Bears also increase the ecological reach of these salmon by catching them in rivers and streams and carrying them deep into the forest to feast. This brings their helpful nutrients, particularly nitrogen, into dense stretches of forest where they can fertilize the ecosystem and help trees grow. In fact, it is estimated that eighty percent of the nitrogen in the trees of the Great Bear Forest in Canada comes from salmon. Learn about the interdependent links of salmon, bears, and forest health here.

Where do we find Pacific salmon?

Pacific salmon are an anadromous species, which means they live in seawater but spawn in freshwater. They hatch from eggs in gravel and spend their early years in freshwater rivers up high in the mountains and forests along the Pacific coast. Then, once they reach about 6-8 inches in length, they move down through the estuarial waters to spend several years in the open ocean, feeding and growing large, before they journey upstream to spawn and die.

What is the cultural significance of these fish?

Pacific salmon are part of a religious cycle of life for Indigenous peoples on the American and Canadian West coasts as well as across the planet. Their annual return is celebrated as part of a natural process in which Autumn brings a bountiful harvest of fish to add to other stores of food to last through a long cold winter. Salmon are objects of worship by coastal native inhabitants, human and nonhuman alike, who depend on the annual return of these salmon in the fall to help them get through a long cold winter.

A Shoshone-Paiute tribal member during the reintroduction of the Chinook Salmon
into the East Fork Owyhee River by the Shosone-Paiute Tribe (May 28, 2015)
(Photo by Jeff Allen, Northwest Power and Conservation Council)

We want renewable energy sources! So why are we destroying them for these salmon?

From the 18th into the 20th centuries, our human thirst for factory power had us constructing many dams on our rivers, with little attention to their harmful ecological impact. Many of our anadromous fish species – adapted to the specific conditions of their river watersheds – were lost forever when dams left them unable to complete their journeys upstream.

It is only in recent decades that a powerful movement for dam removal and habitat restoration has been gaining momentum as a means of saving these precious species. The beneficial effects of removing these barriers have been spectacular, as rivers – freed from their shackles – blossom with new life. Along with the salmon have come a revival of other runs, including steelhead, herring, eels, shad and other diadromous fish (ones that transition between freshwater and saltwater environments), as well as birds and wildlife previously not seen in these areas. Our rivers are showing us all that we had lost and all the flourishing that is possible once we get out of their way.

How are human activities impacting these salmon?

Pacific salmon are in serious trouble. A thirst for hydropower has placed them at dire risk of extinction. We are removing dams, building fish ladders on existing dams (since their proper design is crucial), making sure culverts and other means of fish passage stay open and unhindered. But salmon are cold water species, so a warming planet puts them in peril.

However, there is much we can do to protect them, and restore them once they are threatened or lost. Several short but informative videos on salmon restoration efforts can be found here and here.

May we keep supporting the Pacific Salmon,

Fred

Fred is from Ipswich, MA, where he has spent most of his life. He is an ecological economist with a B.A. from Harvard and a Ph.D. from Stanford, both in economics. Fred is also an avid conservationist and fly fisherman. He enjoys the outdoors, and has written about natural processes and about economic theory. He has 40 years of teaching and research experience, first in academics and then in economic litigation. He also enjoys his seasonal practice as a saltwater fly fishing guide in Ipswich, MA. Fred joined Biodiversity for a Livable Climate in 2016.

Creature: Water Quality Team