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1.
Insect communities at recently burned and unburned sites in the Great Basin of northwestern Utah were studied by weekly sampling with pitfall and Malaise traps. More specimens were consistently collected at the burned site, although the numbers of species between the sites were about equal a month after the fire. Flying insects showing no preference for the sites were sciarids, phorids, and leafminer flies (all Diptera). Insects preferring the unburned site were mostly entomophagous flies such as pipunculids, chamaemyiids, and tachinids. Insects more common at the burned site were mosquitoes and phytophagous species of lygaeid bugs, leafhoppers, and moths. Seasonal trends in relative abundance of major families of flying insects are reported. Ground survivors included gryllacridids, carabids, tenebrionids, and ants. Silphids and buprestids immigrated into the burned area soon after the fire. Interrelationships between the burned area and the insect community are dicussed.  相似文献   

2.
We studied the reproductive characteristics of 2 syntopic lizard species, Sceloporus gadoviae and Sceloporus jalapae (Phrynosomatidae). Specimens of S. gadoviae ( N = 105) and S. jalapae ( N = 41) were collected in a tropical arid forest from Tehuacán Valley, Puebla, México. Males of S. gadoviae reached sexual maturity at the same snoutvent length (SVL; 45.0 mm) as S. jalapae , and a similar pattern occurred in females of both species (SVL; 41.0 and 42.0 mm, respectively). Males of S. gadoviae exhibited reproductive activity throughout the year, with a longer activity during the dry (November to May) and part of the wet season (June to September). In contrast, reproductive activity in S. jalapae males occurred during the wet season (July to September). Females of S. gadoviae showed continuous reproduction, whereas females of S. jalapae exhibited seasonal reproduction. Mean SVL of sexually mature females was higher for S. gadoviae ( ̄ x ± s ̄x = 50.4 ± 0.52) than for S. jalapae (46.0 ± 0.54, P S. gadoviae was lower (3.9 ± 0.14 eggs) than for S. jalapae (5.6 ± 0.43). There was no significant correlation between snout-vent length of females and clutch size of S. gadoviae ( r 2 = 0.22, P > 0.05) or S. jalapae ( r 2 = 0.48, P > 0.05). Our study suggests that although both species inhabit the same environment, they have different reproductive characteristics.  相似文献   

3.
Semiweekly mark and recapture livetrapping was conducted July-October 1985 to determine the effectiveness of wheat treated with inomethacin, a prostaglandin synthetase inhibitor, to control the productivity of a wild population of montane voles ( Microtus montanus ) in southeastern Idaho. Before treatment, control (C) and experimental (E) groups, each on ca 0.3 ha, were statistically equal in population size ( ̄X ± SD; C = 50 ± 21, E = 45 ± 14), adult female: male ratio (C = 1:0.8, E = 1:0.7), juvenile:adult ratio (C =0.16:1, E = 0.13:1), number of juveniles per 100 females ( ̄X ± SD; C = 27 ± 8, E = 21 ± 18), and percentage of pregnant females ( ̄X ± SD; C = 44 ± 10, E = 46 ± 17). After the 15-week experiment all population categories were unchanged for the control group and significantly (P ≤ .05) lower for the experimental group, which ended with a final population of ( ̄X ± SD) 17 ± 6, with 7 ± 21 juveniles per 100 females and an 11 ± 14% pregnancy rate.  相似文献   

4.
The effects of fire on nonbreeding songbird species in riparian habitat have not been studied. We compared body condition, within-year site fidelity, and between-year site fidelity of 3 songbird species ( Passerella iliaca , Fox Sparrow; Catharus guttatus , Hermit Thrush; and Regulus calendula , Ruby-crowned Kinglet) at 2 coastal riparian sites. Wildfire, which is rare in this habitat, had occurred at 1 of the sites before data collection. A significantly larger proportion of Passerella iliaca was recaptured in subsequent winters at the unburned site than at the burned site, but little difference was found between sites for Catharus guttatus or Regulus calendula . Body mass of all 3 species declined during winter at the burned site, but differences between sites were not significant. Similarly, body mass indices of new captures were lower at the burned site than the unburned site for all 3 species, but these differences were not significant. The within-year recapture rate for all 3 species combined declined at the burned site over the course of the study, possibly due to changes in vegetation structure caused by the fire. Overall, our data suggest that wintering songbirds were resilient to this disturbance, but that response to the post-fire environment differed among foraging guilds. Well-replicated studies that include pre-burn data are needed to evaluate the effects of this disturbance in riparian systems.  相似文献   

5.
We compared 3 naturally ignited burns with unburned sites in the Grand Staircase-Escalante National Monument. Each burn site was restored with native and nonnative seed mixes, restored with native seeds only, or regenerated naturally. In general, burned sites had significantly lower native species richness (1.8 vs. 2.9 species), native species cover (11% vs. 22.5%), and soil crust cover (4.1% vs. 15%) than unburned sites. Most burned plots, seeded or not, had significantly higher average nonnative species richness and cover and lower average native species richness and cover than unburned sites. Regression tree analyses suggest site variation was equally important to rehabilitation results as seeding treatments. Low native species richness and cover, high soil C, and low cover of biological soil crusts may facilitate increased nonnative species richness and cover. Our study also found that unburned sites in the region had equally high cover of nonnative species compared with the rest of the Monument. Cheatgrass ( Bromus tectorum ) dominated both burned and unburned sites. Despite the invasion of cheatgrass, unburned sites still maintain higher native species richness; however, the high cover of cheatgrass may increase fire frequency, further reduce native species richness and cover, and ultimately change vegetation composition in juniper woodlands.  相似文献   

6.
The effects of elk ( Cervus elaphus ), pronghorn ( Antilocapra americana ), and mule deer ( Odocoileus hemionus ) browsing on shrubs in big sagebrush ( Artemisia tridentata ) communities were monitored over a 31-year period in Yellowstone National Park. Ungulates were restricting Wyoming big sagebrush (spp. wyomingensis ) heights, size, and recruitment on the lower-elevation stratum only, while no such suppression was observed on the high-elevation stratum. Parallel increases in mountain big sagebrush (spp. vaseyana ) densities and cover occurred over the study period on both browsed and unbrowsed sites at the higher-elevation stratum, although big sagebrush, green rabbitbrush ( Chrysothamnus viscidiflorus ), and horsebrush ( Tetradymia canescens ) were slightly taller and crown sizes were slightly larger on unbrowsed than browsed sites. Wyoming big sagebrush utilization (percent leader use) was eight times higher ( ̄ x = 87 ± 7.2% by pronghorns, mule deer, and elk) on the low-elevation winter ranges stratum (the Boundary Line Area [BLA] portion of the winter range), while mostly mountain big sagebrush with leader use averaged only 11 ± 4.1% (nearly all by elk) on the high-elevation range stratum. In addition, annual aboveground biomass production of big sagebrush did not differ between browsed and unbrowsed study sites on the high-elevation stratum of the winter range. Population turnover was higher on browsed plots versus unbrowsed plots. No difference was observed in percent dieback of big sagebrush adult plants between browsed and unbrowsed plots at the higher stratum. Browsing did not influence the number of leaves or seedstalks per plant ( P > .05), but leaves averaged 45% longer and seedstalks 42% longer on browsed big sagebrush. Ungulate browsing, however, apparently suppressed production, germination, and survival of Wyoming big sagebrush on the low-elevation stratum. Numbers of Wyoming big sagebrush declined 43% and cover declined 29%, 1957-1990, on browsed sites on the BLA. Annual biomass production on browsed sites at the low-elevation stratum was only 6-35% that of unbrowsed sites, and big sagebrush recruitment was less on browsed sites. Percent leader use of big sagebrush did not differ between the period of ungulate reductions, 1962-1969, and the 1980s on the lower stratum ( ̄ x = 87% leader use), but utilization was less on higher portions of the winter range during the period of elk reductions ( ̄ x = 2%) than during the 1980s following cessation of elk controls ( ̄ x = 11%).  相似文献   

7.
The male epiprocts of 2 closely related western Nearctic species, Sweltsa fidelis (Banks) and S. revelstoka (Jewett), were examined using SEM. The males of these 2 species have been historically distinguished by epiproct measurements. The ratio of the length of the base to greatest width versus total epiproct length ranges from 0.49 μm to 0.67 μm ( ̄ x = 0.56) in S. fidelis and 0.55 μm to 0.69 μm ( ̄ x = 0.60) in S. revelstoka . Similarities in measurement suggest that the location of the greatest epiproct width is not a reliable and consistent character for distinguishing males of these 2 species.  相似文献   

8.
The Atlantic Forest is considered a hotspot biome, one of the most diverse in the world. Currently, due to deforestation, only 22% of the original cover remains, and only 7.5% well preserved. Despite the global importance of this biome, it still lacks basic studies, e.g. primary inventories. Cerambycidae is one of the most diverse groups of beetles, with high ecological and economic importance. The aim of this work was to survey the longhorn beetles (Cerambycidae) in three fragments (Pacangê, Vila 5 and Pancada Grande) of Atlantic Forest within Reserva Ecológica da Michelin (southern Bahia State, Brazil). A total of 166 individuals belonging to 53 species were recorded, 15 of them new geographical records for the state, and one for Brazil. The Shannon index (H) shows Pacangê (H = 2.665) as the most diverse fragment, followed by Pancada Grande (H = 2.658) and Vila 5 (H = 2.565). The most abundant species were Nyssodrysina lignaria (38 specimens collected), followed by Compsibidion vanum (31 specimens). One hundred and ten specimens were captured in Malaise traps, while in light traps only 56 specimens were caught; however, the richness and consequently the diversity in light traps was higher. This is one of the few studies carried out in Atlantic Forest surveying longhorn beetles, and provides primary data on these taxa, to help develop conservation policies for this threatened biome.  相似文献   

9.
Resource specialists at Dinosaur National Monument utilize both planned and unplanned wildland ignitions in big sagebrush ( Artemisia tridentata )--dominated plant communities to restore successional processes, maintain vegetation vigor, and promote diversified landscapes. Short- and long-term effects of prescribed burning on small mammal populations are not well understood. The objectives of this study were to (1) compare small mammal species richness, similarity, and diversity between paired burned and unburned treatment plots, and (2) assess long-term trends of small mammal community responses to burning. Five paired burned/unburned sites having similar vegetation, soils, elevation, and annual precipitation were selected. Prescribed or natural fires occurred on all sites between 1981 and 1995, followed by periodic small mammal removal (trapping) sampling (1--12 years post-burn). Small mammal species richness and diversity were generally higher on unburned than burned plots across post-burn sampling years and sites. Increased abundance of the deer mouse ( Peromyscus maniculatus ) following burning resulted in decreased community diversity. Species similarities between burned and unburned plots were low in early post-burn years but increased in later post-burn years. Short-term shifts in diversity and species similarity resulted from increased deer mouse abundance after burning. However, burning had no long-term impact on species richness and similarity, indicating minimal effect to other small mammal species.  相似文献   

10.
Pygmy rabbits ( Brachylagus idahoensis ) are a small sagebrush ( Artemisia tridentata ) obligate lagomorph found within the Great Basin of northwestern United States. Because of its reliance on sagebrush, this species is thought to be experiencing a major range reduction as a result of loss of sagebrush habitat. To aid in conservation of this species, we need to better understand its use of the sagebrush environment. We estimated summer home range use patterns by relocating 5 radio-collared pygmy rabbits (3 females and 2 males) over a 24-hour cycle. We then compared soil texture, shrub density, height, and canopy cover between areas close to burrow entrances and areas of high use and low use. Mean home range sizes of female and male rabbits were 37.2 and 67.9 ha, respectively. Rabbits had disproportionate amounts of time (68.4% ± 9.1, s ̄x ) and travel (63.0% ± 5.7, s ̄x ) in areas within a 60-m radius of their burrows. Soil texture did not differ among the 3 areas, but shrub density, specifically big sagebrush, and forb density were significantly higher close to the burrow than in the high- and low-use areas. We conclude that pygmy rabbits are possibly burrow obligates and that their abundance and distribution are likely limited by available burrow sites.  相似文献   

11.
Physical characteristics, benthic macroinvertebrates, and periphyton assemblages in two adjacent headwater streams in Yellowstone National Park were evaluated five years after the 1988 wildfires. The catchment of one stream was burned by wildfire (burned stream) while the other catchment was unburned (unburned stream). Physical measures revealed channel alteration in the burned stream relative to the unburned stream Periphyton biomass was lower in the burned than the unburned stream (29.2 vs. 50.5 g/m 2 AFDM, respectively), further demonstrating the unstable physical conditions of that system. Kendall's coefficient of concordance (an index of similarity) between diatom assemblages was 0.22, indicating distinct assemblage composition between streams. Navicula permitis Hust. was the most abundant diatom in the burned stream while Hannaea arcus (Ehr.) Patr. was dominant in the unburned stream. Macroinvertebrate taxa richness, density, and biomass were all greater in the unburned stream, although Chironomidae was the most abundant taxon in both streams. Results suggest the removal of terrestrial/riparian vegetation by wildfire can directly influence benthic assemblages by altering the inherent disturbance regime of the physical habitat templet.  相似文献   

12.
Sage Grouse ( Centrocercus urophasianus ) brood-habitat use was examined during 1992 and 1993 at the Yakima Training Center in Yakima and Kittitas counties, Washington. During the 2 yr we followed 30 broods, of which 12 persisted to 1 August ( ̄ x = approximately 1.5 chicks/brood). Food forb cover was greater at all brood locations than at random locations. Hens with broods in big sagebrush/bunchgrass habitat ( Artemisia tridentata/Agropyron spicatum ) selected for greater food forb cover, total forb cover, and lower shrub heights; broods in altered big sagebrush/bunchgrass habitats selected greater tall grass cover and vertical cover height; broods in grassland showed no preference for any measured vegetation characteristics. During the early rearing period (post-hatching-6 wk) each year, broods selected sagebrush/bunchgrass. Broods in 1993 made greater use of grasslands than in 1992 and selected grassland during the late brood-rearing period (7-12 wk). Broods selected for sagebrush/bunchgrass during the midday, but 52% of brood locations in the afternoon were in grassland. Tall grass cover was greater at morning (0500-1000 h) and afternoon (1501-2000 h) brood locations than at midday (1001-1500 h) and random locations. Midday brood locations had greater shrub cover and height than morning and afternoon locations. Selection of habitat components was similar to the results of other studies, but habitat conditions coupled with a possible lack of alternate brood-rearing cover types resulted in low survival of chicks.  相似文献   

13.
ABSTRACT

Fireflies (Coleoptera: Lampyridae) are charismatic insects that have been fruitful model systems in biotechnology. However, lack of information about firefly taxonomy and ecology renders species identification a hard task, especially in the Neotropical region, where fireflies are most diverse. A major gap in the literature on Neotropical fireflies is the lack of knowledge on species’ ecological niches and habitats, which are fundamental aspects for understanding their biology. Here, we provide an annotated checklist of the firefly fauna of the Serra dos Órgãos mountain range (Rio de Janeiro State, Southeastern Brazil), with information on the natural history of each species. We assembled data in three ways: monthly sampling with Malaise traps and active search along an elevational transect from 130 to 2,170 m, over 2 years (2014–2016), extensive field observations, and extracted from historical species records for the Serra dos Órgãos from museum specimens in key collections in Brazil and Europe. We provide a taxonomic key to the genera recorded in the region, and a differential diagnosis for each species, highlighting key references for each taxon. We report 58 species representing 21 genera, making the Serra dos Órgãos one of the richest firefly hotspots on Earth. Most species are restricted to one or two habitat types and/or just one of the regional seasons (warm or cool), and many were only collected either by malaise traps or active search, underlining the importance of sampling different habitat types and seasons, and using different sampling methods when surveying fireflies. Out of the 51 species observed in the field, 49 were active either during the day or the night, although two species – Photuris elliptica and Pyrogaster nigrolineatus – were active in both periods, which is rare in fireflies.  相似文献   

14.
Winter populations of raptors and scavengers were surveyed along 175 km of rural roads in Moffat County, northwestern Colorado. The survey began in 1988 and is currently continuing. Over the 7 yr of the survey reported here, we found Golden Eagles in high abundance ( ̄ x = 5.8 km/eagle) compared to most studies in similar habitat. Bald Eagles were less abundant, but increasing compared to 20 yr earlier. American Rough-legged Hawks were in low abundance, probably due to the predominance of sagebrush habitat along the route. Northern Ravens were seen in low numbers in 4 yr. American Crows were seen in 2 yr. Black-billed Magpies were nearly as abundant ( ̄ x = 6.5 km/magpie) as Golden Eagles and often scavenged with them. Magpie and Golden Eagle numbers were significantly correlated over the years of study. We conclude that northwestern Colorado is a significant overwintering area for Golden Eagles.  相似文献   

15.
The Atlantic Forest is one of the most threatened ecosystems in Brazil, with only 22% of its original coverage remaining. Despite around 900 species of Polistinae being described worldwide and their being widely distributed in the Neotropical region, they are still poorly known in northeastern Brazil, especially in Atlantic Forest. The aim of this work was a survey of social wasps in three fragments of Atlantic Forest with differences in the level of regeneration and in the physiognomy, performed at Michelin Ecological Reserve (located in Igrapiúna, southern Bahia State, Brazil) and employing three methodologies – attractive solution, Malaise trap and light trap ‘Luiz de Queiroz’ – for 12 months in transects. A total of 1066 specimens, belonging to 29 species from nine genera, were collected in the reserve. Epiponini was the richest tribe (23 species) followed by Mischocyttarini (five species) and Polistini (one species). The Malaise trap was not efficient during the night, having a deficit of 5110 hours; the only nocturnal genus, Apoica, was collected with a light trap – an attractive solution that was more efficient. Once it was left for 12 discontinuous days (72 hours), showing that more than one methodology is desirable for wasp surveys. Latitudinal analysis comparing the study area with other areas grouped the Michelin Ecological Reserve with areas in southeastern Brazil, which may be related to a lack of standardization in collecting methods. This study presented the highest richness in this region.  相似文献   

16.
Seventeen subadult, hatchery-reared razorback suckers ( Xyrauchen texanus ; (  ̄x = 456 mm total length) were implanted with sonic transmitters and tracked for 23 months in the lower 89.6 km of the San Juan River (San Juan arm of Lake Powell, Utah). Fish were released at 2 sites, and 9 made extensive up- and downstream movements (  ̄x = 47.8 km; contact was lost with 4, and 4 others presumably died or lost their transmitters). The San Juan arm is primarily inundated canyon; however, most fish contacts occurred in shallow coves and shoreline with thick stands of flooded salt cedar in the upper inflow area. Eight fish frequented the Piute Farms river/lake mixing zone, and at least 4 moved upstream into the San Juan River. Seven fish were found in 2 aggregations in spring (3 fish in Neskahi Bay in 1996 and 4 fish just downstream of Piute Farms in 1997), and these may have been associated with spawning activity. Continued presence of razorback suckers in the Piute Farms area and lower San Juan River suggests the San Juan inflow to Lake Powell could be used as an alternate stocking site for reintroduction efforts.  相似文献   

17.
《Journal of Natural History》2012,46(31-32):1921-1938
We examined the Chrysomelidae communities from representative sites of different ecosystems in Paraná State, Brazil, comparing their spatial and temporal changes. Sampling was undertaken using malaise traps at eight sites during a 2-year period. Chrysomelidae represented 19.1% of all the Coleoptera sampled, with a total of 7611 specimens and 465 species. Galerucinae was the most abundant and richest subfamily. Ponta Grossa was the most abundant site, São José dos Pinhais the richest, Fênix the poorest, Jundiaí do Sul the most uniform, and Antonina had the highest dominance of just a single species. Approximately 79% of the species were represented by fewer than 10 specimens and the 10 most abundant species represented 44.7% of all chrysomelids collected. None of the species were collected at all of the sites, but 325 were unique, reflecting the low similarity among sites. Sites with similar phytophysiognomies were more similar in terms of their Chrysomelidae species compositions. Similarities between years were slightly higher than similarities between sites.  相似文献   

18.
We examined the effect of oil-field development on movements and patterns of spatial use of San Joaquin kit foxes ( Vulpes macrotis mutica ) on the Naval Petroleum Reserves in California (NPRC) in the San Joaquin Valley. To do this, we compared movements and home ranges of kit foxes from June 1984 to September 1985 in areas developed for petroleum production (30% of native habitat lost to production facilities) and areas with little development (3%). Distances traveled nightly by kit foxes did not differ between levels of petroleum development or between sexes ( P > 0.2). Mean length of nightly movements during breeding (14.6 km) was longer than during pup-rearing (10.7 km) and pup-dispersal (9.4 km) periods ( P = 0.01). Mean size of home ranges was 4.6 ± 0.4 ( s ̄x ) km 2 ( n = 21) and did not differ between levels of petroleum development and sexes ( P > 0.2). Overlap of home ranges of foxes from the same social group (78 ± 4.3%) was greater than that of same-sex foxes (35 ± 7.8%) and males and females of different social groups (32 ± 8.0%, P P > 0.4). Despite extensive overlap of home ranges, kit foxes on NPRC maintained relatively exclusive core areas, particularly adjacent foxes of the same sex. Future studies should examine which levels of habitat conversion impact spatial use of kit foxes.  相似文献   

19.
The temporal variation in composition and abundance of the macro-epifauna associated with seaweeds (Ulva lactuca, Cladophora sp., Gracilariopsis longissima and Gracilaria bursa-pastoris) and seagrass (Cymodocea nodosa) was investigated at Menzel Jemil station in the Bizerte lagoon. Twelve replicate samples (25 x 25 cm frame) were collected monthly from October 2009 to September 2010. Sampling data yielded 21,575 invertebrate specimens from floating seaweeds and the seagrass, belonging to 40 taxa, of which 18 species were arthropods, 13 molluscs, three echinoderms, three fishes, two polychaetes and one cnidarian. Crustaceans were the most dominant and the most species-rich group and Idotea balthica basteri the most abundant species, accounting for 28.94% of the total abundance. Minimum (9.25 ± 5.56 species) and maximum (19.75 ± 3.2 species) values of mean species richness were observed in December and June, respectively. Species richness and density of macro-epifauna showed similar trends to plant biomass and the highest values of both indices coincided with periods of maximal plant biomass. Mean values of Shannon’s index H′ and evenness J′ were low, ranging from 0.34 ± 0.02 bit to 1.08 ± 0.06 bit, and from 0.23 ± 0.03 to 0.52 ± 0.07, respectively. The high dominance of herbivores and detritivores highlighted the substantial role played by macrophytes as food source for associated macro-epifauna species. Multivariate analyses also indicated significant seasonal differences for the macro-epifauna assemblage and revealed significant relationships with environmental variables. According to the canonical correspondence analysis, concentrations of phosphates and nitrites, and temperature were the variables that explained the variation of the macro-epifauna abundance in the Bizerte lagoon.  相似文献   

20.
Habitat use and selection by Merriam's Wild Turkeys ( Meleagris gallopavo merriami ) in Wasco County, Oregon, was studied during 1981-82. This turkey population selectively used forested cover types (such as ponderosa pine-Douglas-fir-oak, ponderosa pine-oak) characterized by a variety of structural features, species, and age classes. The population used single species forested cover types (oak, ponderosa pine) less than expected, used nonforested cover types in proportion to their availability, and avoided forested cover types with structure simplified by logging activities. The four age and sex classes had large seasonal home ranges ( ̄x = 1,615 ha); the smallest home ranges were exhibited by adult males in winter and the largest were shown by subadult males in fall. In most instances, turkeys used cover types as they were available. We suggest that structural complexity of vegetation, both within and among cover types, is an important component of habitat for Merriam's Wild Turkeys that should be considered in the evaluation of potential release sites and in habitat management plans.  相似文献   

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