The fish fauna of the area studied is transitional between the Ozarkian
and Great Plains faunas.
Fluctuation in water level seemed especially important in determining
distribution of fishes in the area studied. Variable climate
characteristic of the region studied causes recurrent floods and
intermittency in streams. Both of these conditions have probably been
accentuated by man's modifications of the habitat. The effects of
intermittency were most strikingly demonstrated in small creeks of the
uplands. The number of species of fish in the highly intermittent
streams was small--especially in the uppermost pools sampled--but the
actual number of fish was often high even though the number of species
was low. In several instances the only fishes found in these isolated
pools were _Lepomis cyanellus_ and _Ictalurus melas_. This phenomenon of
concentrated numbers of individuals of a few species would indicate the
presence of limiting factors that allow only those species most
tolerant of the particular factor to flourish.
Soon after rains restored flow in these intermittent creeks _L.
cyanellus_ and _I. melas_ appeared in parts of the channels that had
previously been several miles from the nearest water. Rapid upstream
movements of other species after rains was also noted.
It was impossible to ascertain the precise effects of gradient and
bottom-type on distribution, but certain species such as _Notropis
blennius_, _Notropis girardi_, and _Fundulus kansae_ were taken only in
streams with sandy bottoms. _Notropis deliciosus_ and _Hybognathus
placita_ were most abundant over sandy bottoms.
The high gradient of upland tributaries in the Flint Hills area produced
turbulence and bottoms predominantly of rubble. A fauna of which
_Etheostoma spectabile_ and _Campostoma anomalum_ were characteristic
existed in these waters while they were flowing. As flow decreased and
intermittency commenced, qualitative and quantitative changes in the
fish faunas were observed. Gradient did not change during drought, but
turbulence did. Because turbulence varies with water level as well as
gradient, the effect of gradient on fish distribution ultimately is
linked to climate.
Probably the small number of fish taken on the Walnut River in
comparison with other eastern Kansas rivers (Verdigris, Neosho) results,
in part, from the long-term pollution of the stream noted by Clapp
(1920:33) and Doze (1924). No percid fishes, black bass, or madtom
catfish were taken on the Walnut in Cowley County and the species of
_Notropis_ numbered only three.
Four faunal associations seem to be recognizable in the area.
_Arkansas River Fauna_
This fauna contained _Notropis girardi_, _Notropis blennius_, _Hybopsis
aestivalis tetranemus_, and _Fundulus kansae_ which, in this area, did
not seem to wander far from the sandy main stream of the Arkansas.
Minnows abounded; _Notropis lutrensis_ and _N. deliciosus missuriensis_
predominated; and _Notropis girardi_, _N. percobromus_, and _Hybognathus
placita_ were common. In quiet backwaters, coves, and shallow pools
_Gambusia affinis_ occurred in great numbers. _Lepisosteus osseus_
seemed to be the most important predator.
_Lower Walnut River Fauna_
The Walnut River in Cowley County supported large populations of
deep-bodied suckers, carp, and gar. _Notropis lutrensis_ and _N.
percobromus_ were characteristic minnows. _Lepomis_ _humilis_ abounded
at some stations. The fauna of the main stream of the Walnut River was
somewhat intermediate between that of the Arkansas River and that of the
three streams considered below. Fifteen of the species common to the Big
Caney, Elk, and Grouse systems were also taken in the Walnut River main
stream. Thirteen species were common to the Walnut and Arkansas rivers.
Seven species were common to all these streams.
_Caney-Elk-Grouse Main Stream Fauna_
This fauna includes fishes living not only in the main streams but also
in the lower parts of the larger tributaries of these streams. The fauna
was comparatively rich: in the main stream of Big Caney River 39 species
were taken, in Grouse Creek 35 species, in the Walnut River main stream
21 species, and in the Arkansas River 19 species. It has been pointed
out that large rivers such as the Walnut and Arkansas have been
subjected to greater direct and indirect modification by man, possibly
resulting in a less diverse fauna than would otherwise occur in these
streams. At present, there is a paucity of ecological niches in the
upland tributaries and large rivers, as compared with streams of
intermediate size. Fishes typical of the Caney-Elk-Grouse association
were _Notropis umbratilis_, _Lepomis megalotis_, _Lepomis humilis_,
_Labidesthes sicculus_, _Fundulus notatus_, and the two species of
_Micropterus (Micropterus punctulatus_ was not taken in Grouse Creek).
_Upland Tributary Fauna_
Tributary faunas were divisible into two categories: (1) Those of the
Walnut River and Grouse Creek (intermittency was severe, species were
few, with _Ictalurus melas_ and _Lepomis cyanellus_ predominating); (2)
those of Big Caney River (stream-flow was more stable, and eastern
fishes, some of which have Ozarkian affinities, occurred in greater
abundance than in any other part of the area surveyed). In the latter
streams _Campostoma anomalum_ and _Etheostoma spectabile_ usually were
dominant. _Pimephales notatus_, _Notropis volucellus_, _N. camurus_, _N.
boops_, and _N. rubellus_ characteristically occurred. _Notropis
lutrensis_ was sparsely represented in flowing tributaries. _Notropis
umbratilis_, which seems to prefer habitats intermediate between those
of _Notropis lutrensis_ and Ozarkian shiners, was usually represented.
Deep-bodied suckers and carp were not taken in upland tributaries but
_Moxostoma erythrurum_ was common and _Minytrema melanops_ was taken.
The kinds and numbers of shiners (_Notropis_) taken at different points
along Grouse Creek seem significant. _N. lutrensis_ and _N. umbratilis_
occurred throughout the stream but were rare in sluggish areas where
populations of _Gambusia affinis_, _Fundulus notatus_, and _Labidesthes
sicculus_ flourished. At the lowermost station _Notropis percobromus_
and _N. buchanani_ were taken; these were not present in other
collections. In the uppermost stations where water remained plentiful,
_N. boops_ and _N. volucellus_ were taken, and _N. rubellus_ has been
recorded.
In the broader distributional sense those fishes that seemed most
tolerant of intermittency (_Lepomis cyanellus_, _Lepomis humilis_,
_Ictalurus melas_, _Notropis lutrensis_) are widely distributed in the
Arkansas River Basin, and are common in the western part of the Arkansas
River Basin. Species less tolerant of intermittency are _Notropis
boops_, _Notropis camurus_, _Notropis rubellus_, _Notropis volucellus_,
and _Pimephales tenellus_; they have not been taken far west of the area
studied, and become more common east of it.