Navigation Links
Invasive species alter habitat to their benefit

When scientists study habitats that alien species have invaded, they usually find predictable patterns. The diversity of native species declines, and changes occur in natural processes such as nutrient cycling, wildfire frequency and the movement of water through the system.

But simply observing such changes doesn't prove that the invaders are responsible.

University of Michigan researchers Emily Farrer and Deborah Goldberg, however, came up with a way to tease out the cause of environmental changes in northern Michigan wetlands where invasive cattails have taken hold. The cattails, they found, alter the environment in ways that hinder native species but benefit the invaders. Farrer and Goldberg will present their results Aug. 9 at a meeting of the Ecological Society of America in Memphis, Tenn.

"When you have an invasion, you typically see three things happening at once: the invasion, the change in environment and the decrease in diversity," said Farrer, a graduate student in Goldberg's laboratory group. "But they're all happening concurrently, so you can't really tell which is causing the other." Other factors may enter in. For example, human activity, such as the use of fertilizers and road salt and the suppression of natural wildfires, also may result in environmental changes that affect species diversity.

"My question was, are humans causing the changes, or are the invaders?" Farrer said. "Finding the answer has practical implications: if you're trying to restore a natural habitat, you have to know the cause of the decline in native species. Do you target the invader or try to minimize human interference?"

Farrer began by surveying marshes in northern Michigan to find out what kinds of cattails were there. The state is home to three cattail species: the native broad-leaf cattail; the invasive narrow-leaf cattail, which was introduced on the east coast in the early 19th century and eventually found its way inland; an d a hybrid of the two species that is larger than either parent and tolerates a wider range of environmental conditions.

In the marshes she studied, Farrer found that hybrids were more common than native cattails. She also noted that the areas of each marsh with lots of hybrid cattails had higher nutrient levels and heavier mats of dead cattail stems than areas with only native wetland plants. The plants growing in these invaded areas also were different, with fewer classic wetland species, such as bulrushes, rushes, and sedges, and more typical land plants like grasses, asters, and goldenrods.

Next, Farrer did transplant experiments to figure out whether the invaders were causing the changes she observed. She set up four study plots in a previously uninvaded section of marsh. In one, she transplanted live hybrid cattails; in the second she added litter---the mats of dead stems that accumulate around hybrids. A third plot received both live hybrids and litter, and the fourth was left alone.

Litter accumulation was the deciding factor, she found. "Plots with the litter treatment had higher levels of nitrogen in the soil and higher turnover rates of nitrogen, along with much lower light levels and lower soil temperatures," Farrer said. "So the litter was creating a pretty different environment."

When she tallied other plants in the experimental plots, she found that both the diversity and the density of native species were lower when litter was present. But while native plants suffered, invaders prospered. "The hybrid plants performed better with litter addition," Farrer said. "They obviously aren't hindered by the litter, and the increase in nutrients may help them grow larger."

The results suggest that invasive cattails set in motion a feedback loop that helps them gain a stronghold. "The invasive cattails change the ecosystem through litter accumulation, producing an environment in which native plants don't perform we ll but the invaders do," said Farrer. "As the environment changes, the cattails get more abundant and change the environment even more, resulting in even more cattails. It's interesting---and sobering---to think that it's not just humans that go out and mess up the habitat; invasive species can actually initiate that cycle."


'"/>

Source:University of Michigan


Related biology news :

1. Invasive parasite destroying fish species
2. Minimally Invasive Cancer Treatments Highlighted
3. Invasive species harms native hardwoods by killing soil fungus
4. Invasive exotic plants helped by natural enemies
5. Invasive ants territorial when neighbors are not kin
6. National Academies advisory: Invasive aquatic species in the Great Lakes
7. New species from old data
8. Same mutation aided evolution in many fish species, Stanford study finds
9. Fibril Shape Is The Basis Of Prion Strains And Cross-species Prion Infection
10. Reservoirs may accelerate the spread of invasive aquatic species, researchers say
11. Small species back-up giant marsupial climate change extinction claim
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/13/2017)... PUNE, India , April 13, 2017 According ... Identity Proofing, Identity Authentication, Identity Analytics, Identity Administration, and Authorization), Service, Authentication ... by MarketsandMarkets™, the IAM Market is expected to grow from USD 14.30 ... Annual Growth Rate (CAGR) of 17.3%. ... ...
(Date:4/11/2017)... 11, 2017 NXT-ID, Inc. (NASDAQ:   ... announces the appointment of independent Directors Mr. Robin D. ... Board of Directors, furthering the company,s corporate governance and expertise. ... Gino Pereira , ... forward to their guidance and benefiting from their considerable expertise ...
(Date:4/5/2017)... 4, 2017 KEY FINDINGS The ... at a CAGR of 25.76% during the forecast period ... primary factor for the growth of the stem cell ... MARKET INSIGHTS The global stem cell market ... and geography. The stem cell market of the product ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... 11, 2017  VMS BioMarketing, a leading provider of patient ... Clinical Nurse Educator (CNE) network, which will launch this week. ... among health care professionals to enhance the patient care experience ... and other health care professionals to help women who have ... ...
(Date:10/11/2017)... ... October 11, 2017 , ... ... and pregnancy rates in frozen and fresh in vitro fertilization (IVF) ... maternal age to IVF success. , After comparing the results from the fresh ...
(Date:10/10/2017)... ... October 10, 2017 , ... ... antibody-drug conjugate (ADC) therapeutics, today confirmed licensing rights that give it exclusive ... a technology developed in collaboration with Children’s Hospital Los Angeles (CHLA). ...
(Date:10/10/2017)... -- International research firm Parks Associates announced today that ... TMA 2017 Annual Meeting , October 11 in Scottsdale, Arizona ... market and how smart safety and security products impact the competitive landscape. ... Parks Associates: Smart Home Devices: Main Purchase ... "The residential security market has experienced continued growth, ...
Breaking Biology Technology: