Gm. Linz et al., RESPONSE OF BLACK TERNS (CHLIDONIAS-NIGER) TO GLYPHOSATE-INDUCED HABITAT ALTERATIONS ON WETLANDS, Colonial waterbirds, 17(2), 1994, pp. 160-167
The Black Tern (Chlidonias niger) is considered an endangered species
in some states and is a category two species for listing as a federall
y threatened or endangered species. In the northern Great Plains, catt
ails (Typha spp.) have over-grown many wetlands, contributing to the d
ecline in numbers of Black Terns. We aerially wetlands with glyphosate
herbicide to assess the influence of habitat changes on Black Terns.
In 1990 and 1991, two separate experiments were initiated in northeast
ern North Dakota whereby wetlands were randomly assigned one of three
spray coverages with glyphosate. In one experiment, Black Terns used t
reated wetlands more than untreated wetlands (P < 0.1). In the other e
xperiment, densities of Black Terns were similar between untreated and
treated wetlands (P > 0.1). A stepwise multiple regression indicated
a significant positive relationship between the number of Black Terns
and hectares of water and dead emergent vegetation in the wetland ( r(
2) = 0.51). Black Terns use of a wetland may be positively influenced
by floating mats of dead cattails, live emergent vegetation, and open
water.