Percentage Frequency Of Occurrence Research Articles

Diet of Ringtails (Bassariscus astutus) in Oregon

The ringtail (Bassariscus astutus) attains the northern limit of its range in southwestern Oregon (Hall 1981:964, map 500). In Oregont as in most regionsJ B. astutus is not abundant; estimates of density elsewhere usually are < 5 per km2 (Poglayen-Neuwall and Toweill 1988). It is classified as a sensitive species-undetermined status't by the Oregon Department of Fish and Wildlife on infrequent sightings or reports and is afforded protection against taking in Oregon by state administrative rule (Marshall 1992:RING 1). Other than information contained in general works on mammals (e.g./ Bailey 1936), we know of no published report concerning any aspect of the biology of B. astutus in Oregon. Knowledge of the species elsewhere is fragmentary, especially in comparison with that of most other North American carnivoresX In 1992, a project was initiated by one of us (TPF) to investigate several aspects of the ecology of B. nstutus in the Myrtle Creek drainage, a tributary of the South Umpqua River, northeast of Myrtle Creek, Douglas Co., Oregon (T 28 S, R 3-4 W). Habitats occupied by B. astutus were in Douglas-fir (Pseudotsuga menziesii) forest at elevations of 450-550 m. Most of the area was occupied by regenerating 5-30-yr-old clear-cuttings with older Douglas-fir forest and riparian hardwoods interspersed. Bassariscus astutus usually denned in 15-30-m Douglas-fir snags, but dens occasionally were located in brush piles, downed logs, and stumps. Fifty-six fecal droppings were collected at entrances to dens or at the base of trees containing dens occupied by five B. astutus to which beacon radio transmitters were attached. Dens and individuals were located and identified by radio signals at unique frequencies; nevertheless, all fecal droppings may not have been deposited by the radio-tagged individual occupying a specific den. Herein, we report on the diet of B. astutus in Oregon based on our examination and identification of food remains in those fecal droppings. Fecal droppings were placed in plastic bags, labeled, and frozen. Examination of the droppings followed procedures outlined by Korschgen (1980). Briefly, individual fecal droppings were softened by soaking in water then teased apart and the material distributed fairly evenly over 21 x 32-cm white-enameled trays. Materials that could not be identified in the trays or when picked out and examined under a 7-30 x binocular microscope were dried on paper towels and placed in labeled envelopes for subsequent comparison with museum specimens or identification by specialists of specific taxonomic groups. Results are reported by frequency of occurrence and percent frequency of occurrence by month (Table 1); samples were available for 9 of the 12 months. The diet of B. astutus in Oregon (Table 1) is similar to that reported for the species elsewhere in that it is omnivorous (Grinnell et al. 1937; Taylor 1954; Trapp 1978; Toweill and Teer 1977). Similar proportions of fecal samples contained materials of plant and animal origin (Table 1). Plant material occurred in 93% of the samplesr similar to the 90.6% reported by Toweill and Teer (1977) for the Edwards Plateau in Texas. Trappe (1978) reported 46% of samples from Utah contained fruits, 17% miscellaneous vegetable matter, and 4% graminoids, considerably less frequent than we found among Oregon samples (even if the Utah frequencies were additive). Direct comparison of our findings with those of Taylor (1954), Wood (1954), and Davis (1960) conducted in Texas was not possible because they did not present data by frequency of occurrence. In our study, leaves, scales, and bracts of several conifers; wood; moss; and lichens were consumed throughout the year, whereas berries and seeds were consumed only during summer (August-September; Table 1). Conifer leaves were incorporated into the feces, not merely stuck to themr indicating that the leaves actually were ingested, but on passing through the digestive tract of B. astutus, the leaves exhibited little change. Most other items in the feces were well masticated and/ except for hard items (bone, teeth, chitin, seeds, hair, and cellulose), heavily digested. Ninety-one percent of the samples also contained animal material. Mammal remains were tound in 66% of the samples, considerably more frequent than the 13.7% reported by Toweill and Teer (1977) in Texas, and slightly more than the 55% reported in Utah (Trapp, 1978). Murid rodents were the largest component of the mammalian food items (Table 1), likely reflecting the nocturnal foraging habits of B. astutus (Poglayen-Neuwall and Toweill 1988). Among mammals represented, the red tree vole (Phenacomys longicaudus) occurred most frequently. The house cat (Felis catus), represented

Carnivore Fruit-Use and Seed Dispersal of Two Selected Plant Species of the Edwards Plateau, Texas

Ashe juniper (Juniperus ashei) and Texas persimmon (Diospyros texana) fruit use and seed dispersal potential by four carnivores were studied on the Edwards Plateau region of Texas. Feces were examined to determine presence of seeds and frequency of occurrence by month from August 1989 to February 1990. Use of fruit species by month followed the pattern of fruit ripening of the two plant species. Texas persimmon fruit was consumed primarily between September and January while Ashe juniper fruit was consumed from October through February. Because large numbers of seeds are present in feces and few are destroyed in mastication and digestion all carnivores studied are considered legitimate dispersal agents of Ashe juniper and Texas persimmon. Dispersal efficiency of carnivores, however, is low due to the location of dispersed seeds (feces) and the clumped seed dispersal patterns. The role of temperate carnivorous mammals as seed dispersal agents of fruit-producing plants has been neglected in the literature (Herrera, 1989). Among tropical mammals, monkeys (Howe, 1980; Estrada and Coates-Estrada, 1984) and bats (Morrison, 1978; Fleming, 1981, 1986; Heithaus, 1982; Gribel, 1988) have been studied intensively in recent years although they have long been recognized as important seed dispersal agents (Ridley, 1930; Krefting and Roe, 1949; van der Pijl, 1982). Recently, the importance of herbivorous mammals in seed dispersal has been documented (Janzen, 1981, 1982, 1984) and to a lesser extent the importance of carnivorous mammals has been noted (Stiles, 1980; Estrada et al., 1984). We know of only one study dealing thoroughly with the extent and significance of carnivores (Herrera, 1989) in seed dispersal of temperate fruit-producing plants. Furthermore, little information is available regarding fruit use by North American carnivorous mammals and the associated potential for seed dispersal. This neglect is curious, because it is well known that many carnivores commonly consume fruits (Davis, 1978; Chapman and Feldhamer, 1982). The fact that early work on seed dispersal placed emphasis on coevolution (Smith, 1970; Snow, 1971; McKey, 1975; Howe and Estabrook, 1977) of fruit and dispersers could explain this neglect. Most temperate carnivores have large home ranges and are nocturnal in habits, making any study of them difficult. Because of this difficulty, most information gathered on carnivores and their possible importance as seed dispersers has been obtained through indirect means: analysis of stomach contents and collection of fecal material and the subsequent analysis of their seed contents (Herrera, 1989). However, little information has been reported regarding seed dispersal potential. Herein we report information gathered on selected carnivorous mammals of the Edwards Plateau of Texas, with respect to fruit use and potential seed dispersal of Ashe juniper (Juniperus ashei) and Texas persimmon (Diospyros texana). Data were collected on the diet of four carnivorous mammals known to include fruits in their diets. Particular importance was given to the season and degree of utilization of these fruits by the carnivores and their potential role in the dispersal of seeds is discussed. MATERIALS AND METHODS-The study was conducted between August 1989 and February 1990 at the Texas A&M University Agricultural Experiment Station at Sonora, Texas. The 1430-ha Station is located 45 km SE of Sonora at approximately 1000W and 300N. Vegetation is generally grassland with scattered individuals or mottes (clumps) of live oak (QuerHWESTERN RALIST 38(2):141-145 E The Southwestern Naturalist TABLE 1--Percent frequency of occurrence (%) and numbers (X ? SD, range) of Ashe juniper and Texas persimmon seeds in carnivore feces collected on the Edwards Plateau, Texas, during the fall and winter months of 1989 and 1990. Texas persimmon Ashe juniper

Grupos tróficos de peixes demersais da plataforma continental interna de Ubatuba, Brasil: I. Chondrichthyes

Com o objetivo de detectar grupos tróficos, foram analisadas amostras de conteúdos estomacais de sete espécies de peixes cartilaginosos. Os exemplares foram coletados no período de Outubro/85 a Julho/87 na plataforma interna de Ubatuba, SP, Brasil (da costa, até a isóbata de 50 m). A importância dos itens alimentares foi analisada através da freqüência numérica (FN) e da freqüência de ocorrência (FO). As espécies foram agrupadas em três grupos distintos: Piscívoros: Squalus cubensis; comedores de peixes e crustáceos bentônicos: Raja castelnaui, Raja cyclophora, Raja agassizi; comedores de invertebrados bentônicos: Psammobatis glansdissimilis, Rhinobatos horkelii, Zapteryx brevirostris.

Summer Feeding Habits of River Otter (Lutra canadensis) on the Mendocino National Forest, California

The diet of otters was studied over one season on the Mendocino National Forest in northern California. Undigested prey remains were analyzed from 94 otter scats collected between 18 April and 29 August 1982. Fish were found to be the predominant food, occurring in 89.4% of the scats with a mean volume estimate of 63%. Fishes consumed were primarily catostomids and salmonids. Crayfish and snakes were common prey items as well. Insects were often found in otter scats, but repre- sented little volume. Bird, turtle, frog, and snail remains occasionally were found in the scats. Feeding habits of the North American river otter (Lutra canadensis) have received considerable attention in the literature of wildlife biology, with special emphasis often placed upon the relative proportions of game and non-game fish species taken. One approach has been to study the remains of prey in stomachs or intestines of otters taken by commercial trappers (Lagler and Ostenson 1942; Ryder 1955; Hamilton 1961; Toweill 1974, Lauhachinda 1977). While this method permits relatively accurate esti- mations of prey size and numbers (Lagler and Ostenson 1942), it requires grave com- mitment on the part of the otter. In areas where otter are fully protected, analysis of scats is a workable alternative to digestive tract analysis (Trautman 1936; Wilson 1954; Greer 1955; Sheldon and Toll 1964; Knudsen and Hale 1968; Modafferi and Yocom 1980; Melquist and Hornocker 1983). Scat analysis has certain inherent shortcomings. First, the digestive process renders even some hard parts less identifiable. Second, hard indigestible portions of prey are over- represented compared to soft parts. Mech ( 1970) hypothesized that because of this, smaller prey with greater surface area:volume ratios would be over-represented in scats of carnivores. Floyd et al. (1978) tested this idea with captive wolves and found that smaller animals were indeed over-represented in frequencies of remains in scats. Last, assessment of feeding habits by frequency of occurrence in scats has been shown to be inherently biased, over-estimating food items occurring in low proportions and under-estimating at high proportions (Lockie 1959). Because of this last problem, it has been recommended (Korschgen 1980) that some estimate of volume or weight be included with frequency of occurrence data in all feeding habits studies. Lagler and Ostenson (1942) estimated volumes of otter stomach contents, and Modafferi and Yocom (1980) measured volumes of food items found in otter scats. This communication presents feeding habits information obtained from river otter scats collected in 1982 on the Mendocino National Forest in northwestern California. Data are expressed as percent frequency of occurrence and mean percent estimated volume.

Surface‐feeding on cephalopods by procellariiform seabirds in the southern Benguela region, South Africa

Cephalopod beaks recovered from stomach samples taken from 14 seabird species in the southern Benguela region off Southern Africa and from one species at Sub‐Antarctic Marion Island, were identified as far as possible, counted and the lower rostral lengths (LRLs) measured. Dorsal mantle lengths (DMLs) and body masses of the cephalopods eaten were estimated. The results of analyses by percentage frequency of occurrence and numerical abundance are discussed with reference to present knowledge of the distribution of cephalopods eaten by seabirds in the areas studied. Division of the cephalopod component of seabird diets into species which float, and species which sink, after death indicates that the birds forage on dead or moribund cephalopods on the surface, rather than catching live bioluminescent cephalopods at night.

Feeding interaction between two sympatric species Pagrus pagrus and Phycis phycis around Kastellorizo Island (Dodecanese, Greece)

The feeding habits of red porgy ( Pagrus pagrus L., 1758) and forkbeard ( Phycis phycis L., 1766), captured in 1985–1986 by long line and trammel net, respectively, were investigated on the continental shelf off Kastellorizo Island (Dodecanese, Greece). The frequency of occurrence and number and weight of prey types in the stomach contents were evaluated. The composition of the diet varied between the two species and with season and size of fish. By weight, decapods, fishes, polychaetes, echinoids, anthozoa, gastropods and brachyurans were the most important prey of red porgy, while decapods and fish predominated in the diet of forkbeard. Both species ate more in spring. They preyed during the whole year on the same classes of invertebrates, but differed in their seasonal preferences for particular species. The Index of Relative Importance (IRI), as well as the percentage frequency of occurrence and percentage weight of prey taxa, changed considerably with the fishes size. The largest individuals of each species contained similar classes of food organisms to smaller fish, but in different proportions. The dietary overlap between the two species was very low. Red porgy is benthophagus, feeding on epifaunal invertebrates, while forkbeard is a piscivorous feeder, consuming mainly nektonic animals.

Diet of orange roughy, Hoplostethus atlanticus (Pisces: Trachichthyidae) on the Challenger Plateau, New Zealand

Stomach contents of 687 orange roughy [Hoplostethus atlanticus (Collett, 1889)] from the Challenger Plateau, sampled in March, July and November 1984, were examined. The relative importance of different components of the diet was assessed using three feeding indices which combine, in different ways, percentage frequency of occurrence, percentage number, and percentage weight of prey categories. For both sexes, for all size classes and at any time of the year, the most frequent and abundant components of the diet were prawns, followed by fish, squid, amphipods and mysids. The main natant decapod families were Oplophoridae, Pasiphaeidae, and Sergestidae. Fish, mainly Chauliodontidae and Myctophidae, were the most important prey by weight. Most prey species were benthopelagic and mesopelagic organisms which move towards the surface at night. However, H. atlanticus can be caught by bottom trawl (between 750 and 1 200 m) during any 24 h period, and there was no evidence of vertical migration in search of their prey. When the fish grow in length, there is a transition in the diet from prawns, mysids, and fish, to prawns, fish and squid. Squid were not found in the stomach contents of fish smaller than 20 cm. These dietary changes may be linked to modifications in morphology with growth. The relative proportions of the main dietary items, and in particular the natant decapod families, varied with time of the year. Also, the stomach data seem to indicate an increasing importance of fish and squid in the diet in deeper water. H. atlanticus appears to be an opportunistic predator, consuming a wide variety of invertebrates and fishes. Our results provide evidence to support the notion that benthopelagic predators which consume vertically migrating mesopelagic fish, have an important role in the transfer of energy to the benthos.

Diet of Royal and Rockhopper Penguins at Macquarie Island

The diet of Royal Eudyptes schlegeli and Rockhopper E. chrysocome Penguins, studied during the 1981/82 breeding season on Macquarie Island, is described. Quantitative analysis was performed on 29 stomach samples from Royal Penguins at Bauer Bay (west coast) and 21 samples from Sandy Bay (east coast). Samples were also obtained from 19 Rockhopper Penguins at Garden Cove (east coast). Principal dietary components were Euphausiids: Euphausia vallentini and Thysanoessa gregarra; Amphipods: Primno macropa and Parathemisto gaudichaudi; fish and squid, which were in general unidentifiable. Results of dietary analysis are presented as percent frequency of occurrence, and as percent frequency composition by weight. Considerable differences in dietary composition between the two coasts were observed with fewer euphausiids (45% cf 95%) and more amphipods (86% cf 38%) being taken on the west coast than on the east. Length of time that the parent was away from the chick and the fact that, with only minor exceptions, all dietary species were pelagic indicate that these penguins may feed at a considerable distance from the island.

Some Statistics of Instantaneous Precipitation

Abstract Known sources of data from arrays of instantaneous precipitation intensity recorders in southern Germany, east-central Illinois, northeastern Illinois, central Florida, and Hilo, Hawaii are obtained. These data are analyzed for line averages of the percent frequency of occurrence of the exceedance of selected threshold precipitation intensities. The correlation coefficients of the precipitation intensity at sites at varying distances from a reference site are determined. The decay in correlation is found to be a function of climatic region and the type of precipitation: showery or continuous. Showery rains are found to be essentially uncorrelated about 12 km from the reference site while continuous rain exhibits no correlation beyond about 50 km. Single-station intensity data collected at Urbana, Illinois; Paris, France; Inyanga, Zimbabwe; Bogor, Indonesia; Reading, United Kingdom; Island Beach, New Jersey; Miami, Florida; Franklin, North Carolina; and Majuro, Marshall Islands, are compared.

The biology of the stoat (Mustela erminea) in the National Parks of New Zealand II. Food habits

Abstract The gut contents of 1514 stoats from 14 collection areas (mostly forest or forest edge) were analysed. The distribution of 2643 prey items is expressed as percentage frequency of occurrence in 1250 guts containing food. In the total collection, the frequency of occurrence of the major categories of prey was: mice 19%; rats 6%;, lagomorphs 18%; opossums 10%; birds 43%; lizards 5%; insects 41%; freshwater crayfish 2%; carrion about 1–2%. The diet of stoats in relation to age, sex, season, and habitat was examined more closely in the subsamples from forest (n = 866; three classes of forest recognised) and from Mount Cook (n = 146, the only large non-forest sample). There were no general and consistent differences with age. In all seasons female stoats ate more mice and ground wetas, and males more opossums and ‘unidentified mammals’ (mostly opossums and rats). Grouping the prey as large, small, or medium showed that females ate more small prey (P < 0.01) and males more large prey (0.02 < P < 0.05), ...

Mesophilic fungi associated with cultivation of Agaricus brunnescens

Sixty-six species of mesophilic fungi were isolated from mushroom compost by the dilution plate method and their percentage frequency of occurrence determined at the various stages of composting. Relative cellulolytic activity was measured and strong cellulolytic activity was shown by 57% of the species isolated, while another 35% showed moderate ability to utilize cellulose.

Método gráfico e estimativa de índice alimentar aplicado no estudo de alimentação de peixes

Using a figure which is a combination of volume percentage (Vi) in the axis of x and frequency of occurrence percentage (Fi) in the axis of y it is possible to obtain paralelograms representing the relative importance of the food items. The paralelogram areas are proportional to the volume (%) and frequency of occurrence (%) products; such values are used to calculate a index (IAi). This index'' is proposed as a new method to evaluate the true importance of each food item in the feeding spectrum of each species, as well as to contribute to the understanding of the relationships between several species when applied to fish fauna from the same place and at the same time.

Pine Vole Reproduction in Relation to Food Habits and Body Fat

Pine Vole Reproduction in Relation to Food Habits and Body Fat

The Occurrence and Food Habits of Two Species of Hake, Urophycis regius and U. floridanus in Georgia Estuaries

From 1967 to 1970 a total of 2,683 spotted hake, Urophycis regius and 470 southern hake, U. floridanus were collected and found to exhibit migratory patterns in Georgia similar to northern and Gulf populations of these fish. The food habits of inshore juvenile populations of these two species of hake collected from coastal salt marsh-estuarine areas near Sapelo Island, Georgia were examined. The 341 spotted hake and 192 southern hake examined contained identifiable food items. These were analyzed for the numbers of individual food organisms, percent frequency of occurrence, and percent biomass. The most important group in occurrence and biomass was the Crustacea with Macrura and Natantia most important gravimetrically, Amphipoda and Mysidacea most frequently occurring. These data when combined with the habits of the food organisms established these two hakes as species which use the estuary as “nursery grounds.”

Food of Female Marsh Killifish, Fundulus confluentus Goode and Bean, in Florida

The food of 1945 individuals, 124 to 200 each month of the year, was analyzed. Among the 253 categories identified were: algae, vascular-plant detritus and fresh tissue; three orders, six families and five genera of protozoans; rotifers; a bryozoan; gastropod molluscs of three families, two genera and one species; some pelecypods; polychaete annelids of three families, two genera and one species, some oligochaetes; 18 families, 13 genera and two species of crustaceans, viz., cladocerans, ostracods, copepods (calanoid, cyclopoid, harpacticoid and caligoid), cheliferans, isopods, amphipods, carideans, astacurans and brachyurans; three orders of arachnids; diplopodans; 12 orders, 54 families and 51 genera of insects (one ephemeropteran, five odonate, three trichopteran, 12 dipteran, 10 heteropteran and 20 coleopteran); and three species of fish mostly neonate Gambusia affinis. The total volume was 36% fishes, 21% crustaceans, 18% insects, 11% plant, 7% annelids and 7% molluscs. The breakdown for crustaceans was 9% Palaemonetes, 6% amphipods, 2 % ostracods, 2% cheliferans, 1 % brachyurans, 1% copepods; for insects, 12% dipterans (6% chironomids, 2% ceratopogonids, 1% stratiomyiids, 1% tipulids, 2% other families), 2% hemipterans, 2% coleopterans, 1 % odonates, 1 % hymenopterans; for plants, 7 % fresh vascular, 3 % algae, 1 % vascular detritus. There was no evidence of seasonality in the taking of any item except fishes, whose consumption had a bimodal annual curve, flawed by possible sampling error as to predator size, since consumption of fishes increased with size of predator. The percentage frequencies of occurrence were 2 to 7 times the percentage volumes of the above items except copepods '(34 times), ostracods (18), vascular-plant detritus (11), tipulids (0.8), fishes (0.6) and Palaemonetes '(0.4). Smaller marsh killifish eat fewer Palaemonetes and fishes but not tipulids.

Food Habits of Juvenile Pompano, Trachinotus carolinus, in Louisiana

Abstract Food habits of juvenile pompano (Trachinotus carolinus) in Louisiana were determined during the summer of 1968. Stomachs of 899 juveniles were examined from stations at Grand Isle and Holly Beach, Louisiana. The fish ranged from 10 to 125 mm in total length. Percent frequency of occurrence, percentage of total volume, and seasonal variation in diet were determined. Juvenile pompano in Louisiana ate polychaets, small clams, gastropod larvae, copepods, mysids, isopods, amphipods, postlarval shrimp, anomurans (sand crabs), brachyurans (juveniles, megalops, and eggs), insects, and small fishes. Small juveniles ate a wide variety of organisms and appeared to be opportunistic, apparently feeding on those organisms most abundant at the time. Larger juveniles ate a more limited diet, consisting primarily of coquina clams.

Food and Feeding Habits of the Western Blacknose Dace, Rhinichthys atratulus meleagris Agassiz, in Doe Run, Meade County, Kentucky

Analyses were made of the stomach contents of 934 blacknose dace, Rhinichthys atratulus meleagris Agassiz, from three stations in the upper 3.1 miles of Doe Run, Meade County, KentuckSy. Dipteran larvae ranked either first or second in percentage frequency of occurrence in the diet of individuals of Age Group 0 dace at all station3. Dipteran larvae were replaced by amphipods in percentage frequcnc-yr of occurrence in stomachs of dace in the older age groups at and 2 milcs below the source of the stream. Stomach contents reflected a differ-ncc in feeding habitat between younger and older dace, the younger fccd:nin quiet, shallow water over soft, silty bottoms, and the older in progressively rapid riffles with some vegetation, and deep, eddying pools of vegetation. Gastropods, isopods, and oligochaetes reflected some scazon-I differences in feeding by western blacknose dace. Stomach conten's of western blacknose dace indicated some selectivity with respect to a few groups of benthic organisms. This dace in Doe Run is almost ent:rcly carnivorous in its feeding habits.

Food Habits of the Green Frog, Rana clamitans, in Southern Illinois

Food Habits of the Green Frog, Rana clamitans, in Southern Illinois

A study of the phycomycetes in the soils of Hong Kong

The phycomycete flora of the soil and litter of two areas in Hong Kong with markedly different soils and vegetation was studied for a period of approximately 2 years. About thirty species of phycomycetes of nineteen genera were obtained, using Warcup's soil-plate method. The variation in numbers with depth and season was followed by means of both the soil-plate and the dilution-plate methods. Data on the constancy and percentage frequency of occurrence of the more common members of the flora were obtained. The relationship between the phycomycetes of the litter and of the soil proper was investigated. Preliminary data on mycelial activity and substrate relations were obtained. A number of new or hitherto imperfectly known members of the Mucorales were isolated. These will be described in a separate publication.

PRINCIPAL DIATOMS OF MAJOR WATERWAYS OF THE UNITED STATES

Diatom populations in semimonthly plankton samples collected from 73 stations of major waterways of the United States were analyzed by proportional counts to show percentage species composition of the 4 most abundant species per sample. The species are given for each station to show their relative abundance and percentage frequency of occurrence.