Question

Use the data to answer the following questions.

Data	Treatment	DOC-MAY	DOC-JUNE	TDN-MAY	TDN-JUNE
MEAN	Native	4.58	17.99	15.76	59.17
MEAN	Mosquitofish	3.65	18.91	16.30	69.28
MEAN	Bullfrog	4.23	15.77	19.19	58.00
MEAN	B/F	3.79	17.49	16.67	77.85
S.E	Native	0.79961588	0.90930712	0.8280686	2.81815478
S.E	Mosquitofish	0.28862665	1.2675817	1.2261739	2.03797266
S.E	Bullfrog	0.24207797	0.76273318	1.70102558	1.57886451

How did the two invasive species (Bullfrog and Mosquitofish) influence the dissolved oxygen content (DOC) and total dissolved nitrogen (TDN) in this experiment? If an effect was present, what are the implications for the health of native communities invaded by these two species?

Answer 1

The Mosquitofish and the Bullfrog both slighlty decreased the DOC.

The Mosquitofish increased the TDN while the Bullfrog decreased it.

This is actually good news for the native species as there is more dissolved oxygen in the water.

Also, the depletion in TDN leavels by the Bullfrog is compenstaed by the increase in TDN due to the Mosquitofish.

Since both TDN and DOC levels, on an average, increase, this means more nutrients available for the community. So the native species should remain as healthy, or indeed grow heathier. But since these species are invasive and aggressive competitors, they would get most of the resources and the native species' health will probably decrease.