Repairing Ecologies

A little blog on the big ideas behind ecological restoration

[novel-ecologist]

To the untrained eye, salt marshes don't seem like the coolest ecosystem. They smell like a hard-boiled egg that’s been in the fridge for three months, they're flat, and if you don't watch where you're walking, you could end up knee-deep in a muddy hole. Despite being somewhat unappealing to the senses, salt marshes have some incredible qualities that make them important to the climate, animals, and local communities. Since they are often unrecognized for their better qualities, between 25% and 67% of salt marshes have been altered globally. With the impending doom of sea-level rise and climate change, people are starting to realize the importance of salt marshes in fighting these risks. Fortunately, many researchers have begun to reclaim salt marshes. Aulac may be a small community in New Brunswick, but it’s making big waves in salt marsh restoration. Spencer Virgin, his research team, and other partners conducted the first managed realignments in Maritime Canada, which is reversing historical ecosystem alterations.

The origin story of salt marshes is an amazing one. Salt marshes are an ecosystem that are on the border between marine and terrestrial ecosystems and are heavily influenced by tides. A few thousand years ago, when sea levels began to rise, much of the terrestrial ecosystems on the coast were flooded with seawater, destroying all the plants that lived there. When tides flooded these coastal areas, they deposited large amounts of sediment, which created a blank slate for new species to colonize. However, the salty and waterlogged soil isn't an ideal habitat for most plants. Fortunately, Spartina alterniflora, a salt marsh grass, finds these conditions perfect for survival and stays in the marsh zone that’s flooded daily (Fig. 1). S. alterniflora is known as an ecosystem engineer because it can slow the flow of water and increase sediment deposition, which is critical for other species to establish. Think of S. alterniflora like people in a pool and the tides like a whirlpool. When the people in the pool stop moving, the water circulating in the whirlpool slows. Slow-moving water doesn't have enough strength to carry sediment, so it drops it onto the marsh. Accumulation of soil causes the salt marsh to elevate until it escapes the daily flooding in the high marsh zones (Fig.1). Other grasses, such as Spartina patens, who are less tolerant to flooding and salt, can live in the less frequently floored area that S. alterniflora creates (Fig. 1). As the sediments accumulate and increase the elevation of the marsh, it creates areas even less exposed to tides so salt and flood intolerant species can colonize (Fig. 1).

Figure 1. Salt marsh structure and tidal influence.

Hypothetically, this process of sediment deposition can go on forever. That is part of the reason why salt marshes are so important in the fight against sea-level rise. If salt marshes have space to move horizontally along the landscape, they can continue to elevate and prevent the ocean from flooding neighboring communities. Salt marshes are also one of the most productive ecosystems in the world. They produce new grass annually that can extract CO2 from the atmosphere and store it in their leaves. Finally, salt marshes host many ecologically and economically important marine species, such as striped bass, shrimp, eels, and mussels.

Unfortunately, a huge proportion of salt marshes in eastern North America have been dramatically altered to suit the needs of settlers. How do you alter a salt marsh, and what do you change it to? The sediment the tides bring in from the ocean is chalked full of nutrients and makes a perfect fertilizer. Flat ground and abundant fertilizer create the perfect conditions for growing crops. The only problem is that most agricultural species can’t tolerate salt and flooding. However, farmers found a way around this: in a Trump mentality, they built a wall to keep the ocean out and the nutrients in. These walls are called dikes. But diking causes a problem for salt marshes since tides are one of the driving forces that shape salt marshes. Eventually, salt marshes lose all their carbon sequestration and flood reduction properties.

In New Brunswick (NB), Canada, 30500 hectares (approximately the size of 57000 football fields) of salt marshes have been diked to create farmlands. The Bay of Fundy in NB is known for its nutrient-rich waters, which makes it ideal for salt marsh conversion. The Aulac salt marsh is one of many salt marshes in NB that has been diked. In 2010, sea-level rise and coastal erosion began to wear so heavily at the dike that it broke open. Researchers, local organizations, and the community saw this as an opportunity for restoration. First, they built another dike behind the old one to keep the tides away from the neighboring farms, then removed the old dikes. This process is called a managed realignment and was the first in Maritime Canada. Since the dike was removed, the tides of the Bay of Fundy could reclaim the agricultural fields and turn them back into salt marshes. Virgin et al. saw this as an opportunity to learn about the stages of salt marsh restoration.

After the dike was breached, they did not intervene with any other aspects of the marsh and let the restoration process occur naturally. However, Virgin et al. did conduct an extensive monitoring program to see what steps occurred as the marsh restored itself. Aulac has four salt marshes that are divided from one another, but only two were diked. The remaining two healthy salt marshes are adjacent to the restored ones and were used as a reference for what the final product of the salt marsh restoration should be. Over eight consecutive years, the team monitored changes in plant species, fish and invertebrate communities, and sediment deposition in all four salt marshes. From 2010 to 2018, they noticed a change in the restoration sites from the freshwater grass Spartina pectinata to the salt marsh engineer Spartina alterniflora as sediment increased on the marsh platform. In general, the plant and animal communities became more and more analogous to the reference marshes over time. Although the salt marsh has not yet seen the establishment of Spartina patens and other salt/flood intolerant species, it is firmly in the third stage of salt marsh restoration, where S. alterniflora is abundant and can create the conditions for those species to establish and thrive.

Managed realignment is the perfect compromise to maintain active farmlands while restoring salt marshes that will help combat climate change. For communities like NB, which are at risk for sea-level rise and have lost salt marshes, this research will be an important guideline for future restoration projects.

Cheers,

The Novel Ecologist

Click this link to read the paper

[novel-ecologist]

Fast-forwarding Evolution in the Name of Coral Restoration

We're all familiar with the tale of evolution by natural selection: traits are passed down through generations when they're advantageous to the survival and reproduction of an organism. But evolution can take a long time since beneficial traits need to be continuously selected for and hopefully passed down to future generations until most of the population has those traits. What if we sped up that process to help a threatened ecosystem?

Coral reefs are critically important ecosystems since they provide income to local communities, offer habitat to many marine species, and help prevent the effects of climate change by reducing the carbon concentration in the water. Unfortunately, as climate change has caused ocean temperatures to rise, it's also causing the mutualistic symbiotic relationships between corals and other microbial organisms to be broken. When corals lose their microbial symbionts, they lose their main food provider and die. This coral-microbe breakup is also known as coral bleaching.

Madeleine van Oppen and their team proposed a solution to the coral bleaching problem: assisted evolution. Because ocean temperatures are increasing faster than anticipated, corals can't evolve traits to overcome the loss of their symbionts quickly enough. Assisted evolution works a lot like regular evolution, but instead of letting nature select for traits over a long period, it's done relatively quickly in a lab. Evolution of heat tolerance could be achieved by changing the microbial community in a coral to those that are more heat tolerant, exposing adult corals to high heat so offspring inherit more heat-tolerant genes, or exposing corals and/or their symbionts to heat and selectively breeding for the healthiest individuals. Many fields have successfully used genetic restoration techniques, but they have never been done with corals. However, there is a lot of evidence that corals have stress response genes that would allow these techniques to be implemented.

Assisted evolution is suggested as a restoration technique that would work in unison with traditional coral replanting techniques to help not only re-populate reefs but also help them overcome future effects of ocean warming. It is important to note that this field needs a lot more research before it can be used, but it is a big step forward to restoring corals and the ecosystem services they provide.

Cheers, 

The Novel Ecologist

Read the Article:

van Oppen, M. J. H., Gates, R. D., Blackall, L. L., Cantin, N., Chakravarti, L. J., Chan, W. Y., Cormick, C., Crean, A., Damjanovic, K., Epstein, H., Harrison, P. L., Jones, T. A., Miller, M., Pears, R. J., Peplow, L. M., Raftos, D. A., Schaffelke, B., Stewart, K., Torda, G., … Putnam, H. M. (2017). Shifting paradigms in restoration of the world's coral reefs. Global Change Biology, 23(9), 3437–3448. https://publ.cc/ylMmt

[novel-ecologist]

[novel-ecologist]

For centuries, indigenous communities across North America had maintained a healthy relationship with their local ecosystems and fire by performing cultural burns. The small, controlled fires would create new habitats for game species, promote the growth of medicinal plants, and create travel routes. Following European colonization, cultural burns were criminalized, fire was suppressed, and the battle against fire began. Between the mid-1800s and 1900s, North America experienced some of the most tragic wildfires in history. In the U.S, the final straw was the Big Burn of 1910. The combination of drought, excessive dry wood on forest floors, and human-caused accidental fires produced hundreds of fires to be ignited from the western United States into southern Canada, destroying over a million hectares of forests. Following the fire, regulations were implemented to ensure these tragedies never happened again, much of which we still see today. Governments have continuously tried to suppress fire throughout history, but they keep getting worse. In the past few years, fires have been breaking out in increasing severity across the west coast of Canada, including some of the most precious protected areas like Jasper National Park (JNP). Unfortunately, changes in fire patterns are not the only changes being seen in JNP.

How did we go from having controlled fires that helped the landscape to ones that caused mass destruction? To answer that question, we must first understand why fire is an important natural disturbance. Many ecosystems require fire cycles to keep them healthy. The cycle starts with a mature forest that has a diverse community of trees and plants that live under the canopy (Fig. 1-1). They often have fuel on the forest floor, such as dried wood and leaves. When the conditions are dry and a spark is lit, by humans or lightning, a fire will break out in the forest (fig. 1-2). A system with a healthy fire cycle and minimal fuel due to a recent burn will only burn a controlled area, cleaning the forest floor. Once the fire has opened the habitat, surviving plants and seeds in the soil colonize the landscape. The species that colonize first are called pioneer species and can make the post-burn conditions more hospitable for other plants (fig. 1-3). Once the pioneer species have regenerated soil conditions, shrub species can colonize (fig. 1-4). As the shrubs continue to create a more suitable habitat with abundant nutrients and shade, tree species can colonize (fig. 1-5). As more species arrive and others die, a greater diversity of species can join the community and restore the area to a mature forest. The different habitats also provide resources to animals, which allows them to join the community too. As many small fires burn over space and time, more than one stage in the fire cycle can exist, creating a healthier and more diverse landscape.

JNP’s mountain ecosystems are one of many ecosystems that needs fire to stay healthy. But over the past few years, JNP has been struggling with continuous high wildfire risks across the park that threaten its survival. But that's not the only issue they're facing. Forests are also struggling to cope with mountain pine beetle (MPB). The MPB beetle is an insect that infests mature trees and can kill them. Although they are naturally occurring in some areas of the Rocky Mountains, MPB are infesting new areas and getting out of control. Finally, much of the landscapes are changing and look almost unrecognizable from their historic states.

In 2002, Jeanie Rhemtulla and their team conducted a study to look at how the mountain ecosystems in JNP were changing over time. Although many studies looking at ecosystem changes use vegetation sampling, Rhemtulla et al. took a different approach. The researchers acquired over 700 photos taken in 1915 by M.P. Bridgland. These photos captured details of the habitat and vegetation types of the mountain ecosystems in the Athabasca River Valley. Eighty-two years later, the Rhemtulla et al. took identical photos to those from 1915. They were also able to get their hands on aerial photos from the same region from 1949, which Rhemtulla et al. replicated in 1991. Using electronic classification programs, the photos were analyzed for different types of vegetation, land cover, and habitat types. By comparing the data from the two periods, the researchers were able to determine how the ecosystem had changed over time. They found that in less than 100 years, there were drastic changes in the mountain ecosystem. There was an overall change from young and diverse habitats like grasslands (fig. 1.3) and open forests (fig. 1.5) to mature forests (fig. 1.1). The diversity in species, habitat, and vegetation types in 1915 and 1949 had decreased dramatically over time. Although this type of succession is natural in an ecosystem’s fire cycle, there is a key element missing: fire. The researchers explained that the last huge fire events that occurred in the park were in 1889. Like the rest of Canada, JNP was subject to fire suppression following the expropriation of indigenous communities and the establishment of the park. But the decrease in fire events, such as cultural burns, and increase in mature forests has caused undesirable changes. Since there are decades worth of accumulated fuel in the mature forest, accidental fire events (like a gender reveal gone wrong) could have catastrophic impacts on the protected area and the adjacent communities. The researchers also outline how fire suppression is causing the MPB outbreaks. Because the grasslands and young forests are starting to turn into dense forests with mature trees, there are more hosts available for MPB to invade. When MPB kills the trees it invades, they provide even more fuel for fires, creating a positive feedback loop.

Studies that use repeat imagery, such as the one conducted by Rhemtulla et al., show exactly how ecosystems have changed over time and are a very useful tool in restoration ecology. They tell us if the ecosystems are changing outside their natural state and provide a blueprint of what the ecosystem should look like based on healthy historical conditions. One of the biggest challenges in ecological restoration is deciding what historical state to restore an ecosystem to. You could restore a forest into a wetland if you wanted to, but it might not be what's best for the area. Studies like these can provide specific project goals. The team who conducted the research work closely with Parks Canada and hopes to use these studies to help restore the ecosystems. Thankfully, Parks Canada is starting to restore ecosystems health by fighting fire with prescribed fire. Prescribed fires are small, controlled fires that create new habitats for different animals, burn built-up fuel, and help restore the historical fire conditions to the park (sound familiar?). At the same time, park managers are restoring the ecosystems, they are restoring the practices of land stewardship and controlled burns that indigenous communities pioneered long ago. After centuries of damage, the government has finally understood the traditional ecological knowledge and importance of fire.

Cheers,

The Novel Ecologist

Want to know more? Check out these links:

Post-Disturbance Succession: https://www.adfg.alaska.gov/static-sf/statewide/aquatic_ed/AWC%20ACTIVITIES/FORESTS%20&%20WILDLIFE/BACKGROUND%20INFORMATION/Forests%20IV_Succession%20Facts.pdf

Parks Canadas’s Prescribed Fire Program: https://www.pc.gc.ca/en/nature/science/conservation/feu-fire/feuveg-fireveg/dirige-prescribed

Repeat Imagery in JNP: https://www.researchgate.net/publication/236952649_Eighty_years_of_change_Vegetation_in_the_montane_ecoregion_of_Jasper_National_Park_Alberta_Canada

Historical Fires: https://www.firescience.gov/projects/09-2-01-9/supdocs/09-2-01-9_Chapter_6_Fire_History_The_View_from_Ecosystems.pdf

Wildfire Ecology: https://www.alieward.com/ologies/fireecology?rq=wildfires

[novel-ecologist]

Restoring Chernobyl: How Nature Made a Comeback

In 1986, a devastating explosion at the Chernobyl Nuclear Power Plant destroyed the site and its surroundings. Following the tragedy, the Chernobyl Exclusion Zone (CEZ) was established as a restricted area completely shut off from the public. However, unlike the power plant, much of the CEZ had been agricultural land. If you’re anything like me, you may be wondering what happened to the ecosystems within the CEZ. Did they come back, or were they destroyed forever?

Luckily, I stumbled upon a scientific paper that answered that exact question. In 1998, a team of ecologists flocked to the site to see if nature would reclaim the site. Active restoration is a type of restoration that requires human intervention. But it is not the only type of restoration that exists. The restoration project in the CEZ uses passive restoration, where human interactions are limited so nature can reclaim the area on its own terms. Although the team didn’t actively restore the CEZ, they did check in on species in the ecosystem. Specifically, they surveyed raptors, also known as birds of prey. Since raptors are highly specialized to certain conditions and sit on top of the food chain, these bird species are a good indicator of the health of the ecosystem they live in. Over the 22 years the project ran, the research team found incredible changes in not only the raptor species but also the ecosystem itself. As the agricultural area turned into a wetland, many species, including endangered and previously locally extinct raptors, repopulated the site.

This study illustrates that nature can heal itself from human inflicted damage when given the chance, even if that damage seems irreparable. If you want to hear more about this restoration success story, then give the paper a read!

Cheers,

The Novel Ecologist

Read the Paper:

Dombrovski, V. C., Zhurauliou, D. V., & Ashton-Butt, A. (2022). Long-term effects of rewilding on species composition: 22-years of raptor monitoring in the chernobyl exclusion zone. Restoration Ecology, (20220113). https://doi.org/10.1111/rec.13633

[novel-ecologist]

Welcome to Repairing Ecologies

Hello there. Welcome to Repairing Ecologies!

Do you love getting out into nature? Do you hate seeing forests being torn down to make another strip mall in your hometown? Have you ever lied awake at night wondering how we (we, being the human race) have gotten here (here, being a catastrophic climate crisis)? Have you thought about what can be done to address the changing planet? If you answered yes to any of these questions, then you are not alone.

My name is Jenna, and I'm a student of Science and Biology at the University of New Brunswick. Since I could remember, I wanted to be a dentist. But this changed during my first year of university, where I was introduced to environmental biology. I fell in love with the idea of working as an ecologist and having nature as my office, wearing a uniform of sunscreen and Tilley hats, and never having clean fingernails. In a matter of months, I changed my life goal from becoming a healthcare professional to someone who gets paid to play outside (sorry, Dad). Once I realized my passion for ecology, I engulfed myself in the world of science and tried to satisfy my thirst for knowledge within this field. 

During some of my summer jobs doing ecological monitoring research, I had the opportunity to work on many incredible projects, but three really captured my interest. The first project was using salmon breeding programs to increase the wild population size of the endangered species. The second was promoting the regrowth of forests in unused trails. The third project monitored the return of animal and plant species to a system that had been converted from a salt marsh to an agricultural field and back into a salt marsh. There is a common thread among these three projects: a part of nature was being returned to its former state through human intervention. In other words, each aspect of the environment was being ecologically restored. Restoration ecology is a growing field and has a lot of potential to help address many of the changes we are seeing in nature through climate change, urbanization, or other anthropogenic causes. When I learned about restoration, I fell in love as it is one of the best tools we can use to help repair damaged ecosystems. This blog will explore the benefits, challenges, and stories surrounding ecological restoration and its potential to impact our changing world.

If you're interested in science, the environment, and alleviating some climate anxiety, then I welcome you to this blog.

Cheers,

The Novel Ecologist