These resources are brought to you by the Cooperative Extension System and your Local Institution

Welcome

eXtension is an interactive learning environment delivering the best, most researched knowledge from the smartest land-grant university minds across America.

Find a U.S. Institution

eXtension: more mind reach

Have a question? Try asking one of our Experts

Riparian Health - Understanding Plant Vigor

Last Updated: August 16, 2011

View as web page

The Role of Vigor in Riparian Health

Riparian species that are healthy and displaying good vigor may indicate a healthy riparian area.

Looking at the vigor of riparian plant species will help to ascertain if plants are healthy and robust or are weakened or stressed and leaving the area. What is happening aboveground is a reflection of the condition belowground and the ability for riparian-wetland species to hold an area together. As riparian vegetation weakens or leaves an area, the area is subject to degradation.

Determining Vigor, or the Lack of Vigor

Vigor is difficult to quantify, possibly because the relative health of plants within a community is expressed in many morphological and physiological forms. It is helpful when evaluating vigor to separate woody plants and herbaceous plants. The reproductive indicators explained in Riparian Health - Understanding Riparian Vegetation Age-Class and its Role in Health, as well as plant size, leaf area and size, seed production, and root growth are all associated with relative plant health or vigor. Reduced height or reduced leaf area (production) and signs of stress, such as chlorosis, have traditionally been used as indicators of reduced vigor in herbaceous species. Growth form, leader length, and the amount of dead or dying limbs are indicators of vigor for shrubs and trees.

Warning Signs

Riparian species that are dying off are a sign of low vigor.

Some warning signs that plant vigor is low or in decline, which may indicate declining health or “unraveling” of riparian areas include:

High amounts of dead limbs in woody species – A loss of vigor and the subsequent loss of a plant altogether, is a sign that vigor in the plant is declining. This could be a sign of old age.

Willow leaves turning yellow during the growing season – This decrease in vigor usually occurs as a result of water being removed or added to a system, which stresses the plants. This can also indicate a disease or soil nutrient problem or climate factors.

Herbaceous species such as sedges occurring as isolated plants or broken clumps – Sedges exhibiting high vigor in their systems usually form dense communities which form mats along riparian areas. Low vigor may be exhibited by an inability to form these communities.

Narrow leaves of sedges - Some sedges, such as Nebraska sedge tend to have wide leaves (~ thumb width) just up from the base when vigorous. Narrow leaves (~ pencil width) indicate stress from lack of moisture, excess grazing pressure or some other cause.

References

Surber, G., B. Ehrhart. 1998. Stream and Riparian Areas Management: A Home Study Course for Managers. Montana State Extension Service. Information also available at http://www.animalrangeextension.montana.edu/riparianmgt/index.htm

USDI Bureau of Land Management. 1998. Riparian Area Management: A User Guide to Assessing Proper Functioning Condition and the Supporting Science for Lotic Areas. Technical Reference TR 1737-15. 124 pp. More Information available at: http://www.blm.gov/or/programs/nrst/index.php

Browse related Articles by tag: rangelands, rangeland plants, rangeland water

Have a specific question? Try asking one of our Experts

Unlike most other resources on the web, we have experts from Universities around the country ready to answer your questions.

These resources are brought to you by the Cooperative Extension System and your Local Institution. eXtension provides objective and research-based information and learning opportunities that help people improve their lives. eXtension is an educational partnership of 74 universities in the United States.