Rocky Streams Research Articles

Influence on the variation in initiation of breeding in Peromyscus maniculatus

Correlates of the initiation of breeding by female Peromyscus maniculatus borealis (Mearns) were examined to test the hypotheses that asynchronous breeding was related to age, weight, matriline, and nest-site habitat. Life-history data were collected by mark–recapture techniques and by monitoring natal nests over two breeding seasons in 1985 and 1986. Timing of initiation of breeding was related significantly to nest-site habitat and age, but not to matriline or weight. At approximately the same altitude, females nesting in dry rocky stream beds bred first, followed by those in open rock fields, then shrub areas, and last in subalpine forest. Youngest animals bred first in all habitats, although the relationship between age and initiation date was weak. Habitat effects appeared to be primarily related to microclimatic effects. The influence of habitat on the timing of initiation of breeding also had consequences for reproductive success, total reproductive output, and survival. Reproductive success of first litters was greatest for females nesting in rocky stream beds in the spring and least for females nesting in shrub and forest habitats. The apparent advantages of early breeding in rocky stream beds were offset by greater overwinter mortality.

Decomposition of Rainbow Trout (Oncorhynchus mykiss) Carcasses in a Forest Stream Ecosystem Inhabited only by Nonanadromous Fish Populations

The overall dynamics of rainbow trout (Oncorhynchus mykiss) carcass decomposition in a woodland stream ecosystem was examined in two experiments conducted in the West Fork of Mink Creek, Idaho: one during winter–spring (mean water temperature 4.2 °C) and one during summer (mean water temperature 8.6 °C). Relative weight loss (%AFDW) from fish during both periods was essentially constant. In spring, mean daily loss per day was 1.5%. Although this rate is comparable with the decay of high-quality ("fast") leaves, it took much longer than expected (> 120 d) for the even higher quality fish protein. In summer, decay was more rapid (4.9%/d) and was completed in less than half the time (~50 d). Most decay appeared to progress from inside the carcasses outward to the skin. The skin remained intact throughout most of both experiments. Nutrients leached from the fish appeared to be utilized rapidly by microbes associated with the carcass, since no stimulation of algal growth occurred immediately downstream of the carcasses. This suggests extremely tight nutrient spirals and high nutrient retention in Mink Creek and other comparable Rocky Mountain headwater streams.

Heavy metal contamination in the River Toad,Bufo juxtasper (Inger), near a copper mine in East Malaysia

Mining of metals creates a potential source of heavy metal contamination in the environment. An open pit copper mine situated in the Northwest of Sabah, East Malaysia has been known to pollute its surroundings especially with discharges involving heavy metals. Although extensive investigations of heavy metal pollution has been carried out, none of the studies performed so far has included amphibians as indicator of heavy metal contamination in the area. As amphibians live both on land and in water, a study on the heavy metal content of these animals will thus enable a more extensive evaluation of the degree of contamination by heavy metals. Bufo juxtasper was chosen since it inhabits the rocky streams and rivers which exist in both a polluted and non-polluted condition in Sabah. Its' tadpoles are herbivorous feeding mainly on plant detritus, while adults feed principally on ants (which are polyphagous). Furthermore the large adult size of Bufo juxtasper, in which the size of the liver has an allometric relationship with body size, may allow for differentiation between larval and adult uptake through regression analysis. Thus concentration of pollutants acquired only during the larval phase should show a declining or negative slope as a function ofmore » body size in adults.« less

Demography of the Hellbender Cryptobranchus alleganiensis in the Ozarks

Hellbenders Cryptobranchus alleganiensis were sampled by markrecapture in four rivers: C. a. bishopi in the Spring River, Arkansas, and Eleven Point River, Missouri, and C. a. alleganiensis in the Gasconade and Big Piney rivers, Missouri. Densities ranged from 0.9-6.1 hellbenders per 100 m2, biomass from 66-418 kg per ha. Growth of hellbenders decreased linearly as a function of total length in all populations. Spring River hellbenders exhibited the greatest length-specific growth, Eleven Point River hellbenders the least. Females exhibited a greater length-specific mass than males in all populations. Fecundity was a positive linear function of female body length. The mean number of eggs produced per female was 480, 450, 429 and 365 by the Spring River, Gasconade, Big Piney and Eleven Point river females, respectively. Age-specific production of ova was also greatest by Spring River females because of greater growth and consequent larger body size. It was least by Eleven Point River females. INTRODUCTION Cryptobranchus alleganiensis is a large aquatic salamander with two subspecies. The hellbender C. a. alleganiensis inhabits swift rocky streams from southern New York to northern Georgia and W through Tennessee and the Ohio River Valley to four Nflowing streams in the Ozarks (Dundee, 1971); the Meramec, Gasconade, Big Piney and Niangua rivers. The Ozark hellbender C. a. bishopi is known from the Spring River in Arkansas (Dowling, 1957) and from the Current, Eleven Point and North Fork rivers in Missouri (Firschein, 1951), all S-flowing, heavily spring-fed streams. The hellbender is a habitat specialist because its success is dependent on a constancy of dissolved oxygen, temperature and flow found in swift water areas (Williams et al., 1981). Thus the hellbender may serve as an indicator species for cool, unaltered streams. Smith and Minton (1957) reported that the range of the heilbender was rapidly decreasing because of human modification of stream habitat. In particular, impoundment, channelization, siltation, acid mine drainage and thermal pollution have reduced habitat for hellbenders (Dundee, 1971; Nickerson and Mays, 1973a). The status of the hellbender is uncertain in at least six states; it is endangered in two, and may have been extirpated in Illinois (Williams et al., 1981). Although stable populations exist in the Ozarks (Nickerson and Mays, 1973a), demographic data exist only for Niangua and North Fork river populations (Nickerson and Mays, 1973a; Taber et al., 1975; Topping and Ingersol, 1981; Peterson et al., 1983). Therefore, the objective of this study was to provide information by mark-recapture on the population dynamics of four other populations to serve as a reference for future evaluation of the status of the hellbender

Diel periodicity in density of Ephemeroptera nymphs on stream substrata and the relationship with drift and selected abiotic factors

The diel periodicity in density of Ephemeroptera nymphs on an undisturbed stream bottom was documented by direct observation. The study was conducted in a second-order Rocky Mountain foothill stream in Alberta. Observations were made for 24-h periods, twice during a new moon and twice during a full moon; the times of the dark and light periods were noted. Nocturnal observations were made using a red light. The abundance of drifting nymphs, incident light, percent cloud cover in the sky, and water temperature were recorded to determine if they were related to the observed diel periodicity on top of the substratum. The taxonomic groups of Ephemeroptera nymphs examined were Cinygmula, Heptageniidae (Cinygmula and Epeorus), Baetis, Baetis–Ameletus, Ameletus, Drunella coloradensis Dodds, and total fauna (all groups including minor taxa). In response to the artificial light used for observations, total fauna, Cinygmula, and Baetis nymphs were not affected by the light, and the nymphs were not found to be negatively phototactic. Total fauna and Heptageniidae nymphs exhibited a diel periodicity between 24-h periods; the Baetis–Ameletus group also had a diel periodicity. Cinygmula, Baetis, and D. coloradensis nymphs did not exhibit a diel periodicity. Most taxonomic groups were at greater densities on the top of the substratum in the dark period than in the light period. For small and large size classes of nymphs examined, only the small Heptageniidae and Baetis–Ameletus nymphs showed a diel periodicity in density. Drift of the common groups of nymphs was aperiodic and not statistically correlated with the diel density of nymphs on the substratum. In general, incident light, percent cloud cover, and water temperature were not correlated with the diel density of the taxonomic groups on the top of the substratum.

Fojia bumui, an Unusual New Genus and Species of Scincid Lizard from New Guinea

Fojia bumui, a new genus and species of lygosomine skink is described from speci- mens collected near small, rocky streams at low to middle elevations around Huon Gulf, Papua New Guinea. The taxon is a derivative of the variegatus species group of Sphenomorphus. It differs most noticeably from its nearest relatives, and indeed most other skinks, in having normal sized middorsal scales juxtaposed with tubercular lateral scales; all dorsal scales with pustules, and in mature males, patches of glands on the chin, abdomen and underside of the thighs and tail base. The ecological associations of these structures in Fojia and other squamates are discussed.

A new species of torrent toad (Genus:Ansonia) from Silent Valley, S. India

A new species of torrent toad,Ansonia rubigina is being described from a rocky stream in Silent Valley, South India. Although resembling closely the only other species, viz.,Ansonia ornata described from India, it is specifically distinct.

THE FOOD AND FEEDING APPARATUS OF THE BLUE DUCK HYMENOLAIMUS

SUMMARYThis paper describes a preliminary study of the feeding behaviour of the territorial Blue Duck. The bird is unusual in possessing lateral bill flaps and, in a number of head and skull characters, differs from a typical dabbling duck. Herbst's corpuscles are absent from the outer 60% of the width of the flaps and this is thought to indicate that any tactile function is subsidiary. It is tentatively suggested that an additional function is protective, and that the flaps cushion the jaw edges during vigorous food searching beneath stones on rocky stream bottoms. Food taken in summer was analysed from remains in droppings and from gut contents and was found to consist of aquatic insects, principally case‐living and free‐living caddis larvae, and algae. Some short‐term variation in the diet was noted. It is suggested, also tentatively, that the decline in Blue Duck numbers since the 19th century has been associated with the introduction of trout which are potentially direct food competitors. Further ecological research on this unique species is required.

The Patagonian Telmatobiid Fauna of the Volcanic Somuncura Plateau of Argentina

The Late Tertiary basaltic rocks of the Patagonian Meseta of Somuncura, Rio Negro, Argentina, extend for about 15,000 square km north of 42? South Latitude, approximately 60 miles from the Atlantic coast. It is a flat stepparian landscape of some 1200-1400 m elevation in which many temporary clay-lagoons are scattered. Small rocky streams filter from the basaltic uplands towards the lower slopes of the Meseta, about 700-500 m. The fauna of such an isolated environment is very peculiar and a high rate of endemic forms can be emphasized. Two new species of telmatobiid frogs are reported: Telmatobius reverberii from the clay-lagoons of the stepparian uplands, and Telmatobius somuncurensis from the lower rocky streams. Adults and tadpoles of Telmatobius reverberii are described; this form has morphological and ecological affinities with the smaller Telmatobius praebasalticus of the volcanic lagoons of Neuquen, near the Southern Argentine Cordilleras. Certain characteristics of Telmatobius somuncurensis are discussed, such as the uncommon everted cloaca and the similarity between the upper and lower rounded structures of its iris and the upper meniscus of the iris of the east-Brazilian Cyclorhamphus. Probable biogeographic relationships and a tentative evolutionary history of these ancient leptodactylid stocks are discussed.

Muskellunge in Tennessee Streams

Abstract Muskellunge (Esox masquinongy)are known to inhabit 169 miles of rocky and fast-flowing streams on the Cumberland Plateau in East-Central Tennessee. These waters are usually clear (turbidity less than 5 p.p.m.) and slightly acid. Muskellunge in Tennessee streams grow an average of 5.8 inches per year but few fish live beyond 6 years of age. Male fish mature when about 22 inches long and 3 years old; females mature when about 25 inches long and 3 or 4 years old. Muskellunge spawn in April when water temperatures are near 50° F. Young fish are found in only 15 percent of the total habitat distance. Management of the muskellunge streams in Tennessee appears to be necessary to maintain the presently small muskellunge fishery.

The Markets and the Mores: Economics and Sociology

Several looked more prosperous as they looked more full of energy than the others. When I looked out the window, I saw the same mixture: badly eroded hillsides and desolate looking fields of unharvested, spindly corn or cotton alternating with carefully tilled farms green with winter cover crops and beautiful wooded hillsides and pastures with rocky streams running through them. In Rome itself there were new levees for the rivers, a new county hospital under construction, and every sign of a soundly vigorous industrial growth. I was reminded of Matthew Arnold's lines:

Two New Blind Isopods from Northeastern Oklahoma

On December 27, 1935, a large new Caecidotea was found in a 6mall stream in a cave five miles south of Kansas, Oklahoma. The stream pursues a very narrow and rocky course, and, at this time of year, being nowhere niore than two feet wide or eight inches deep, until it emerges upon a bed of guano some fifty feet from the mouth of the cave. It was in this shallow, muddy area that the greatest aggregation of Caecidotea was found, doubtless due to the fact that more organic matter which would serve as food was here available. In this pool were also found great numbers of a new species of white turbellarian, (which is being described by Dr. Libbie Hyman), and numerous larvae of Eurycea lucifuga and Eurycea melanopleura. In several instances, many of the turbellarians were seen aggregated in one spot, and, in each instance, a dead Caecidotea was found upon which the former seemed to be feeding. In the small rocky stream the Isopods and flat-worms were found in diminished numbers, but the Eurycea larvae tended to give way to Typhlotriton as the muddy pool was left behind. A number of the specimens of the Isopods and salamander larvae were taken and kept alive for well over a month. The Caecidotea seem to be able to stand considerable temperature changes with no ill effects as the specimens were several times inadvertently left in a hot room until the temperature of the water had risen to a point far above that to which they were accustomed. One of the salamander larva kept with the Isopods was one day observed eating a Caecidotea, but whether it was taken alive remained a question. It has been noticed that many of the Isopods taken have one or. both of the terminal appendages missing. Observation seems to indicate that this is due not only to attacks by salamander larvae but to the isopods fighting among themselves. The first walking leg is modified as a formidable offensive weapon and the captive specimens have at several times been seen attacking one another.

Impressions of the Ferns of Porto Rico

Save a narrow strip along most of the coast Porto Rico is all hills and hollows. Except along the dry south coast, ferns are in evidence almost everywhere from sea level to the highest summits, becoming more plentiful the greater the altitude. My first day in the highlands was October 23 at Maricao, which we reached about half-past seven, after two hours' ride up the winding road through the cool morning mists, past coffee and banana groves, the roadside banks in places completely covered with ferns. After caf6 at the fonda we set out, following up the Rio Maricao, scrambling over the rocks and in and out of the water most of the way. Maricao is 1500 feet high and we ascended some five hundred feet only in the five or six miles we made up river. The beauty of that rocky stream of clear rushing water, its banks hung with strange trees and shrubs and gorgeous flowers, with ferns everywhere they could find a foothold, on rocks, on the trunks and branches of trees, was intoxicating. I met my first tree ferns here. One, some 25 feet high, a species of Alsophila, was collected in fruit. It has fronds six or eight feet long, the stout woody stipes beset with spines like a blackberry cane. On its trunk were growing Polypodium asplenifolium L., its long narrow fronds drooping over on their slender fuzzy stipes, and Trichomanes

Mount Milanji in Nyassaland

HIDDEN in the recesses of one of the recently issued Parliamentary Papers (Africa, No. 5, 1892) will be found a very interesting report on the mountain and district of Milanji, in British Central Africa, by Mr. Alexander Whyte, F.Z.S., one of Mr. Commissioner Johnston's principal assistants in the task of ruling and developing the new British Protectorate of Nyassaland. Mr. Whyte was sent to Milanji by Mr. Johnston in October last, and dates his report from the “Residency, Zomba, British Central Africa,” in the month following. Milanji is a large mountain mass in the extreme south-east corner of Nyassaland, drained on the west by the head waters of the Ruo, one of the affluents of the Shiré, and on the east by the Lukuga and other smaller streams, which run into the Indian Ocean north of the Zambesi. It is described by Mr. Whyte as an isolated range of, for the most part, precipitous mountains, the main mass forming a huge natural fortress of weather-worn precipices or very steep rocky ascents, sparsely clothed with vegetation. Many of its gullies and ravines are well wooded, and in some of them fine samples of grand African virgin forest are met with. Mr. Whyte's ascent, on the 20th of October, was made up the south-east face of Milanji, over steep grassy hills and across rocky streams, full of large water-worn granite boulders. Further on precipices were encountered, and it was necessary to clamber up, holding on by tufts of grass, roots, and scrub, after which a wooded gorge was entered, and welcome shade was obtained from the forest trees.