The fauna of the Neosho and Marais des Cygnes rivers is capable of a
wide range of adjustment in response to marked environmental changes. As
these rivers become low and clear they take on many of the faunal
characteristics of smaller tributaries and ponds. Species such as black
bullhead, spotted bass, largemouth, white crappie, red shiner,
rosy-faced shiner, blunt-faced minnow, mimic shiner, and slender madtom
assume a more prominent position in the total population. Other species
such as channel catfish, flathead, freshwater drum, blue sucker, and
such riffle-dwelling species as the gravel chub, Neosho madtom, and
slender-headed darter hold a less prominent position in the total
population.
When permanent flow is re-established the more mobile and the more
generalized species (with respect to habitat) are able to utilize the
available space immediately. As a result, these species increase rapidly
in numbers. This increase occurs both by movement from more permanent
waters and by reproduction. Channel catfish, flathead, freshwater drum,
and river carpsucker are mobile species (Funk, 1957; Trautman, 1957) and
long-nosed gar probably are mobile. Individuals that move supplement
those that survive in residual pools, and provide brood stock adequate
to produce a large year-class in the first year of permanent flow.
The five species last mentioned are found in diverse kinds of streams,
indicating that they are adaptable to varying habitats. A sixth species,
the red shiner, although probably less mobile, is able to utilize
opportunistically nearly any kind of habitat in Plains streams.
Although this species seldom is abundant in riffles, it was, in 1957,
abundant in both pool and riffle situations at all my stations. These
riffles were almost unoccupied by other species in 1957 until
mid-summer, when hatches of channel catfish and flatheads occurred.
Although adult channel catfish and flatheads live well in pools, the
young occupy mainly riffles. This age- and size-segregation, in
different habitats, was an advantage to the rapid re-establishment of
these species in the Neosho and Marais des Cygnes rivers in 1957.
Species that occupy restricted habitats, especially riffle-dwellers such
as the Neosho madtom, gravel chub, and slender-headed darter, were
slowest to increase following drought. These species seem less capable
of adapting to the variable conditions prevalent in the Neosho and
Marais des Cygnes rivers than species that have more generalized
habitat-requirements.
In the Neosho and Marais des Cygnes rivers nearly all species that were
found in years just prior to the drought of 1952-1956 were again found
in the last year of my survey; however, some species that live in a
restricted habitat may eventually be extirpated in these two rivers. The
high-finned carpsucker _Carpiodes velifer_, common shiner _Notropis
cornutus_, horny-headed chub _Hybopsis biguttata_, and johnny darter
_Etheostoma nigrum_ all have specific habitat requirements and have
disappeared or become restricted to one tributary in the Wakarusa River
System (Deacon and Metcalf, 1961). The disappearance or reduction of
these species implies long-term changes in the environment.
Suckers, minnows and catfishes constitute the main fauna of the Neosho
and Marais des Cygnes rivers, because these families contain many
species that have generalized habitat-requirements. Many of these fish
are able to live successfully in either ponds or flowing waters and
others are capable of long migrations. Because these fish predominate in
the streams of Kansas, attempts should be made to utilize them more
effectively.
In years such as 1957, large numbers of young channel catfish could be
collected and used to stock new ponds and lakes. So doing would not
affect the numbers of _adults_ produced in the stream, and, if enough
young could be removed, those remaining in the streams might grow
faster.
Suckers and carp are abundant in the two rivers and mostly are unused at
present, because current regulations preclude the use of methods
effective for the capture of these species.