//
you're reading...

Climate Change

Agricultural Stewardship Could Prevent Invasive Species Takeover Downstream

 

Phragmites australis, or Common Reed, is a marine grass likely introduced to North America from Eurasia in the late 1800s through the garden trade. It has since become one of the most aggressive invaders in history, replacing native grasses in wetlands and disrupting native ecosystem function.

A saltmarsh in Georgia (Trish Hartmann, Wikimedia Commons)

Wetlands are interesting study systems for invasive plants. Waterlogged and acidic, there are only so many plants that can live in these habitats. In the plant world, competition between species is almost always over space – and where in the wetland any individual species ends up depends on both the species’ tolerance for the local conditions and who is already occupying the area.

Like other invasive species, Common Reed grows fast, reproduces via several strategies, and has a broad range of tolerances to different stressors. Together, these traits make it good at both colonizing new space in a wetland and pushing other species out of their way.

It is considerably easier for a new species to take hold in an ecosystem when space is freed up by some disturbance, and coastal wetlands along the eastern seaboard have been dramatically altered by human activities since European settlement; some deliberately drained for farmland, some polluted by nutrients from farm runoff (manure and other fertilizers), and all of them exposed to the effects of global climate change. Common Reed takes advantage of its competitive traits to spread and thrive in these wetlands, colonizing disturbed patches and then kicking out neighbouring vegetation.

Invasive Phragmites australis, Common Reed (c1.staticflickr.com)

The native Spartina alterniflora, or Smooth Cordgrass, is particularly threatened by the spread of the Common Reed. Common Reed can form root beds twice the depth of Smooth Cordgrass, is tolerant of saltier conditions, and spreads quickly underneath the mud into new areas. How the invader and its native competitor react to local stressors (predominantly agricultural runoff and the effects of climate change) are important processes to understand if scientists hope to effectively manage the invading Common Reed.

Legault et al. from the University of New England investigated the dual effects of nutrient pollution and increased temperature on the competition between Common Reed and Smooth Cordgrass by monitoring their productivity (how well or fast they use their resources) in simulated laboratory environments. They exposed an equal number of Common Reed and Smooth Cordgrass plants in laboratory tubs to increased nutrients and temperature, with and without competition from the other species, and looked for differences in how the plants fared through time.

Plants like extra nutrients, as they live in nutrient-limited environments, so the addition of Nitrogen and Phosphorus can be expected to increase plant productivity. That’s why you see algae blooms when nutrient pollution is really bad. Common Reed is particularly nutrient-hungry and is known to increase productivity when its habitat is nutrient saturated. Plants generally do not like competition, so one would expect both of the grasses to be less productive in a competitive environment where they have to share their limited resources. Most of Legault’s findings are consistent with this – more nutrients means more growth, more competition means less. Interestingly, the team found that higher temperatures seemed to change the way the plants act in response to nutrient load and competition.

At normal temperatures, increasing nutrient levels resulted in greater productivity (size, number of new shoots) in both the invasive Common Reed and native Smooth Cordgrass. But at high temperatures, the beneficial effect of extra nutrients levels off and there is less of an increase in productivity, even though nutrient levels are high. This effect was particularly evident in the invasive Common Reed. In fact, Smooth Cordgrass was better able to maintain its productivity in the higher temperature system and was more productive even without the nutrient addition.

Runoff of nutrients from farm fields can harm coastal wetlands. (Lynn Betts/USDA)

Legault et. al.s’ results suggest that the native Smooth Cordgrass could have an advantage if temperatures continue to rise due to climate change and future nutrient pollution from land-based sources can be minimized. Because so much of the nutrient pollution along the east coast originates from farms, the widespread adoption of on-farm best practices for reducing runoff could go a long way towards preventing future invasion of the Common Reed. Considering the high cost of invasive species removals once they become established, preventative strategies like reducing runoff are likely to be the most cost effective way of saving our native wetlands.

 

Article: Legault R II, Zogg GP, Travis SE (2018) Competitive interactions between native Spartina alterniflora and non-native Phragmites australis depend on nutrient loading and temperature. PLoS ONE 13(2): e0192234. https://doi.org/10.1371/journal.pone.0192234

 

 

 

 

 

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 2 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 3 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 3 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 5 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 7 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 8 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 8 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 9 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 9 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 10 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 11 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 11 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com