With due respect, I would hereby request the scientific brethren to provide me a formula with examples to calculate the "impact" or "degree of impact" of alien invasive plant species in the introduced ecosystem.
I, would, hereby like to re-state that I am in need of a formula. Although, I have found certain formulae, but the variables are not clearly defined.
For example, Parker et al. (1999) suggested I (overall Impact)= R (range) × A (abundance) × E (per capita impact). Now, how to calculate R & E, is not clear!
Again, Lockwood et al. (2007) states I = Ft × Fe × Fs × E; how to calculate Ft, Fe, Fs & E is not stated!
Ricciardi (2003) opines Impact = A × F (ecological function per capita effect) × C (composition of recepient community); but no clarity with respect to calcuation of F!
I am at a loss!!!
Thanking you.
In my opinion, an important factor is the type and the structure of the plant community invaded. Moreover, another aspect to be considered is the scale of the study. I think you can find out many issues about this question on internet. I'll give you some suggestions:
Article Impact of invasive plants on the species richness, diversity...
Chapter Impact of Heracleum mantegazzianum on invaded vegetation and...
Best regards
You need to determine biodiversity in ecosystems with and without the alien species and compare them using glm :)
Dear Ankur,
Please have a look at these useful links.
Article Ecological Impacts of Alien Species: Quantification, Scope, ...
Conference Paper Impacts of alien invasive plants on resident species, commun...
Chapter Impacts of invasive plants on ecosystem functioning and biod...
Article Impact of Invasive Plants on the Structure and Composition o...
https://vtechworks.lib.vt.edu/bitstream/handle/10919/24362/120120.pdf;sequence=1
http://www.belspo.be/belspo/SSD/science/Reports/ALIEN%20IMPACT%20-%20FINAL%20REPORT%20ML.pdf
http://www.scielo.org.za/pdf/babc/v47n2/02.pdf
https://lib.ugent.be/fulltxt/RUG01/002/217/316/RUG01-002217316_2015_0001_AC.pdf
Good luck!
Dr. Bellver, Dr. Pegman & Dr. Singh,
I thank your kind selves for your pain in giving me a reply.
I, would, hereby like to re-state that I am in need of a formula. Although, I have found certain formulae, but the variables are not clearly defined.
For example, Parker et al. (1999) suggested I (overall Impact)= R (range) × A (abundance) × E (per capita impact). Now, how to calculate R & E, is not clear!
Again, Lockwood et al. (2007) states I = Ft × Fe × Fs × E; how to calculate Ft, Fe, Fs & E is not stated!
Ricciardi (2003) opines Impact = A × F (ecological function per capita effect) × C (composition of recepient community); but no clarity with respect to calcuation of F!
I am at a loss!!!
Thanks!
With regards
Ankur J. Saikia, RFRI
Dear Ankur,
An old paper for your files in case you did not read it.
Best,
Guy
You might be interested in the concept of coefficient of conservatism which are being employed in some states. The rating for field sites indicates the degree of infestation relative to native plant composition. https://www.pca.state.mn.us/sites/default/files/wq-bwm2-01.pdf
Dr. Wieland,
Is coefficient of conservatism employed in assessing the invasiveness of an invasive plant species with respect to the ecosystem of occurrence?
Although, as stated in my question, Parker et al. (1999), Ricciardi (2003) and Lockwood et al. (2007), have devised formulae; they are not clear about the variables, e.g. R (range) & E (per capita impact); Ft, Fe, Fs & E and F (ecological function per capita effect); respectively.
I seek your help!
No, the Coefficient of Conservatism (C) value is simply a numerical rating of an individuals specie's conservatism and habitat fidelity in relation to disturbance. C values range from 0-10 and are assigned by a panel of botanists. Non-native species are not assigned C-values as they were not present during the evolution of local plant communities though they may be assigned a C-value of 0. C-values are used in the Floristic Quality Index (FQI) formula which is considered a dispassionate and repeatable measure of ecological condition. FQI = the mean C value multiplied by the square root of the number of species identified in the community, or species richness, occurring in the area that is being evaluated. The greater the mean C and FQI values, the greateris the codition of the evaluated area. FQI in this case is essentially a weighted species richness index. The link provided previously was used to build this response. So as the composition of a community becomes occupied with invasive species, the FQI score is lowered.
The FQI could be useful, especially if you have pre-infestation or reference data for comparison. Coefficient of Conservatism lists now exists for many area/regions. If a list for your region does not exist then you can create one (usually compiled with insight of local vegetation experts/botanists).
These document contain FQI info, eqs, and might be useful:
http://www.dtic.mil/dtic/tr/fulltext/u2/1039133.pdf
https://pubs.usgs.gov/of/2011/1097/
Article Development and use of a Floristic Quality Index for coastal...
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