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1.
Variation in kit fox ( Vulpes macrotis ) population parameters can be influenced by vegetative cover and the distribution and abundance of other predator and prey species. Dramatic changes to Great Basin Desert habitats, which can potentially impact mammalian species, have occurred in some areas in Utah. We examined kit fox demographics and prey populations from 1999 to 2001 on Dugway Proving Ground (DPG), a U.S. Army facility in Utah, and compared some parameters to historical levels (1956–1958, 1966–1969). Adult survival rates were fairly consistent between 1999 and 2000 and between 1999 and 2001; however, survival was greater in 2001 than in 2000. Reproductive rates ranged from 1.0 to 3.8 pups per female in 1999–2000 and were similar to historical numbers (1.0–4.2 pups per female). We found a decrease in pre-whelping kit fox density from the 1960s (0.12 foxes ? km –2 ) to 1999–2001 (0.04 foxes ? km –2 ); however, densities were similar between the current study and the 1950s (0.08 foxes ? km –2 ). Using 9 years of data, we found density dependence between reproductive rates of the current year and annual fox density from the previous year. Using 7 years of data, we found a slight correlation between kit fox annual density and a 1-year lag in leporid abundance, even though leporid abundance was lower during the present study than it was historically. Compared to historical levels, current small mammal abundance and species composition has changed in several habitats. Kit fox breeding density and annual density were inversely correlated with coyote ( Canis latrans ) density. Changes to the landscape at DPG, especially due to invasion of cheatgrass ( Bromus tectorum ) and addition of artificial water sources, have caused a change in available kit fox habitat and prey species, and have increased the abundance of coyotes, the kit fox's major competitor.  相似文献   

2.
The uncontrolled, global increase in atmospheric CO 2 concentration (ca 80 ppmv) and decline in δ 13 C air (ca 1.5%) since industrialization provide experimental boundary conditions by which to assess physiological response of vegetation. To examine consequences of these global atmospheric changes in the southwestern U.S., 350 specimens of Atriplex confertifolia, A. canescens, Ephedra viridis, Pinus edulis, P. flexilis, Juniperus scopulorum, and Quercus turbinella of precisely known age spanning the last 150 years were acquired from 9 herbaria. Cellulose analysis of δ 13 C plant and estimation of isotopic discrimination (Δ) permitted calculation of water-use efficiency (A/g). The δ 13 C plant chronologies of C 4 Atriplex spp. show some promise as a reliable proxy for δ 13 C air because their mean trends approximate the known δ 13 C air chronology. However, the high variability would necessitate multiple samples at any time period to accurately represent the mean. The generally increasing A/g trends of the 5 C 3 species are particularly pronounced for P. edulis and, after the 1950s, for J. scopulorum, but less evident for P. flexilis, E. viridis, and Q. turbinella, evidencing possible differences in species response to rising CO 2 concentrations. The trends are statistically noisy, however, possibly due to complex microclimates, extreme seasonality, and great interannual variability typical of the southwestern U.S. Herbarium specimens, at least in the Southwest, may be less useful for precise detection of direct CO 2 effects on plant physiology than tree rings, where the variability can be constrained to a single individual over time.  相似文献   

3.
Summary

The flowers, fruit and seed of Dracontomelon costatum Blume are here described for the first time. It is remarkable in that four of the five carpels present in the flower are suppressed during fruit development. Information concerning habit and habitat is also included.  相似文献   

4.
Climate change and fire suppression have facilitated expansion of pinyon-juniper woodlands into sagebrush-steppe ecosystems of the Great Basin, USA, resulting in a loss of biological diversity. To assess the effects of using prescribed fire in restoration efforts, ant abundance, species richness, and composition were examined pre- and post-burn along the elevation and tree cover gradients encompassed by a pinyon-juniper woodland in a central Nevada watershed. Ants were sampled using pitfall traps in 6 sites for the elevation study and in 2 sites for the tree cover study, representing paired burn and control sites in a randomized block design. Vegetation and ground cover variables were also sampled to determine how variation in ant populations was correlated with differences in vegetation and ground cover. Ant species richness remained unchanged for all treatments. Tree cover had no significant effect on ant populations. Significantly more ants were trapped after the burn treatment on burn plots. Variation in ant populations was not directly correlated with any of the vegetation or ground cover variables. According to ANOVA and multivariate analyses, elevation had the greatest effect on changes in ant communities, likely due to increased moisture availability. Our results suggest that management for conservation of sagebrush-steppe ecosystems in this and similar watersheds should include a range of elevations to ensure maximum ant species diversity.  相似文献   

5.
Chrysididae is a diverse group of parasitoid/cleptoparasitic wasps; however, host–parasite relationships and life cycles of few species have been studied. Nests of different wasp and bee species were obtained during a trap-nesting programme, in the Pampean region. Some of these nests were parasitised by cuckoo wasps females of Caenochrysis taschenbergi (Mocsáry), Chrysis boutheryi (Brèthes), C. saltana Bohart, C. sp. 1 (ignita-group), C. sp. 2 (ignita-group), Neochrysis lecointei (Ducke), Pleurochrysis ancilla (Buysson) and P. lynchi (Bréthes). This paper reports new data about host–parasite relationships and life cycles for these species. Multiple parasites (from one species or from different families of insects) emerged from single cells of some parasitised nests: from each host cell parasitised by species of Pleurochrysis, two adults emerged successfully, information previously unknown for the genus; and in three cases of cells parasitised by C. boutheryi, two adults successfully emerged from a single cell; in two cases both individuals were chrysidine, and in third one was chrysidine and one Leucospis pulchripes (Leucospidae).  相似文献   

6.
7.
Landscape modification is a key driver of global species extinction. Thus, understanding how species react to changes is essential for effective conservation management in modified landscapes. We examined the impact of selected land use patterns on the critically endangered Ceratophora tennentii in the Knuckles mountain range of Sri Lanka where lizards occupy patches of both natural undisturbed forests and modified plantations – evidently, those with a forest canopy. We tested three potential explanations for non-random habitat selection: availability of suitable microhabitat pockets, availability of prey and direct threats from humans. The microhabitat pockets occupied by the lizards were characterised by shade, humidity and the density of perches. Most lizards were found in mixed cardamom forests followed by natural forests and cardamom plantations, but none were observed in the pine plantations. Food availability showed similar patterns among habitats. Direct mortality by humans did not influence the distribution of this species. Our work indicates that habitat modifications that retain the structural complexity of the vegetation would still permit the existence of the species in densities equal to or greater than that of undisturbed forest patches. It adds to a growing body of literature that signifies the importance of disturbed habitats (intermediate disturbance hypothesis) in protecting threatened species of fauna. It is highly unlikely that some disturbed habitats will be ever be returned to their former pristine state in time frames that are important for species’ conservation. Hence, attention is needed in developing suitable approaches to manage and conserve species across disturbed habitats.  相似文献   

8.
9.
《Journal of Natural History》2012,46(14):1655-1678
A study was carried out of the protozoan ciliate epibionts present on diverse decapod crustaceans from two areas of the north-west Mediterranean. A total of 92 crustaceans was examined (65 brachyurans and 27 anomurans, belonging to 15 species). Seventeen ciliate species were identified (two heterotrichs, two chonotrichs, ten suctorians, and three peritrichs). This is the first record of the family of folliculinid ciliates as epibiont on crustaceans in Mediterranean waters. The suctorian Acinetides symbiotica, considered endemic to Lake Nyassa, was found in the sampling areas. Local variations, microlocation on the surface and anatomical units of the decapods, and differential distribution of epibionts were also considered.  相似文献   

10.
Habitat modification, pollution, overfishing, poaching, competition from non‐indigenous species, and diseases have led to the extinction in Europe of many populations of indigenous crayfish. Under the rationale that any programme of reintroduction should be preceded by a thorough understanding of habitat requirements of the species of concern, we studied the microhabitat use of an Austropotamobius pallipes population in Tuscany, central Italy. Microhabitat use was assessed for water depth, current velocity, substrate, percentages of boulders, underwater tree roots, and in‐stream vegetation cover. Results show that A. pallipes' habitat use is size‐partitioned. Smaller individuals mostly occupy stream edges in shallow waters with submerged roots, whereas larger individuals use deeper waters, often associated with boulders. Crayfish spatial distribution is restricted mostly to the microhabitats characterised by extensive cover and slow current velocity. The study highlights the importance of habitat heterogeneity and cover elements for the protection of this indigenous species.  相似文献   

11.
Since Euro-American settlement, fire exclusion and other factors have dramatically altered interior western coniferous forests. Once open and parklike, present-day structure in many southwestern Pinus ponderosa forests consists of dense stands of young, small-diameter trees, with small patches of larger, old trees, and relict open bunchgrass areas. Our objectives were to assess differences in soil properties associated with these different vegetation patches. We examined soil morphological characteristics, pH, organic C concentration, total N concentration, C:N ratio, and phytolith concentration from profiles within 6 transects (18 soil pedons) crossing patches of dense stands of small diameter trees, patches of old-growth trees, and open grassy areas. Results indicate that old-growth plots had significantly lower A horizon pH and thicker O horizons than grass plots. In general, we found vegetation patches had statistically similar C and N concentrations and C:N ratios for A and B horizons; however, C in the A horizon was positively correlated with O horizon accumulation ( r 2 = 0.79). Greater accumulation of organic C in the A horizon of forested areas contrasts with commonly reported results from mesic, mid-continental prairie-forest ecosystems but is typical for many arid, semiarid, and humid savanna ecosystems. Phytolith concentration was similar among old-growth pine, dense younger pine, and open grassy plots; the lack of a spatial pattern in phytolith distribution could indicate that grass cover was more spatially continuous in the past. Additionally, this interpretation is consistent with current theories regarding historical vegetation change in these forests.  相似文献   

12.
Salmincola californiensis is a parasitic copepod in the Lernaeopodidae family that commonly parasitizes salmonid fishes ( Oncorhynchus spp.) by attaching near the fins and on gill filaments. Historically their distribution was limited to streams that emptied into the Pacific Ocean. During the summer of 2006, several rainbow trout ( Oncorhynchus mykiss ) captured in Lake Tahoe were infested with S. californiensis . This is the first known record of S. californiensis in Lake Tahoe.  相似文献   

13.
The southern Oregon–northeastern California and extreme northwestern Nevada (hereafter “SONEC”) region provides critical spring migration habitat for waterfowl and other waterbirds in the Pacific Flyway. Information on the dynamics and distribution of waterbird habitats in SONEC during spring is needed to guide conservation efforts in the region. We grouped 1992 National Land Cover Data classes into 5 potential waterbird habitat types and used Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus satellite imagery to map flooding of these habitat types in SONEC during February–May, 2002 and 2003. SONEC included 13,727 km 2 of potential waterbird habitat comprised of grasslands (37.1%), pasture/hay (24.6%), marsh (15.9%), open wetland (11.8%), and croplands (10.6%). On average, 11.9% of this potential habitat was flooded during spring; but the percentage, area, and composition varied within and among years and subregions. Total flooding increased from 693 km 2 in February to 2099 km 2 in April during 2002 and from 1630 km 2 in February to 2125 km 2 in May during 2003. Open wetland comprised 58%–74%, marsh 8%–18%, pasture/hay 4%–11%, grassland 4%–17%, and cropland 3%–8% of the flooded habitat in SONEC. Satellite imagery and land-use data provided useful estimates of waterbird habitat availability in SONEC during spring, but other methods should be tested to more accurately measure flooding of densely vegetated habitats such as marsh. With <12% of the potential habitat flooded on average during spring, conservation programs have ample opportunity to improve the SONEC landscape for migrating waterbirds.  相似文献   

14.
《Journal of Natural History》2012,46(35-36):2327-2362
This paper critically compares the Southern African bulldog fish species Marcusenius macrolepidotus (Peters, 1852), inhabiting the eastern Lower Zambezi River, and Marcusenius altisambesi Kramer et al., 2007, inhabiting the central Upper Zambezi River, with bulldog fish samples from the western lower Cunene River, a 2600-km range from the Indian Ocean to the Atlantic. The three species or forms are well differentiated in morphology and molecular genetics, and differentiation is also present in electric organ discharges. Marcusenius altisambesi and the Cunene sample, which we recognize as Marcusenius multisquamatus sp. nov., are closely related and form a sister taxon to M. macrolepidotus. This result is based on the analysis of mitochondrial cytochrome b sequences and genomic Inter-simple-sequence-repeat fingerprinting. Morphological adaptations to life in a torrential escarpment river seem to be present in M. multisquamatus sp. nov. when compared with M. altisambesi, which lives in a reservoir river that periodically floods the savannah. http://www.zoobank.org/urn:lsid:zoobank.org:pub:8FE68494-9ED9-428E-B181-E814D25493F2  相似文献   

15.
《Journal of Natural History》2012,46(31):2913-2933
Members of two hunting‐wasp families, Pompilidae and Sphecidae, are among the major predators of orb‐web spiders. In this study, we collected paralysed spiders from natural nests and trap‐nests provisioned by sphecids in an area of Brazilian Atlantic Forest, and compared these data with the composition of species collected by visual searching during one year. Prey preferences were analysed based on the relative abundance of spider species, their size and web characteristics. We also compiled a list of orb‐weavers captured by four sphecid genera reported in 40 other studies. A large number of prey was obtained from natural nests of Trypoxylon (Trypargilum) albonigrum in Parque Estadual Intervales, especially species of Eustala, Parawixia, and Araneus (Araneidae). Other prey, stored in trap‐nests by T. lactitarse and unidentified hunting‐wasp species, included Nephila (Tetragnathidae), Parawixia, Ocrepeira, Mecynogea, Acacesia (Araneidae), and other spider species that were less abundant. All the species that were heavily preyed upon had a relatively lower abundance in our samples of prey availability. The range of body sizes of spiders captured by Trypoxylon in our study area include the size of some abundant orb‐weavers always absent in their nests. These results indicate that factors other than abundance in the field and the spider's size influence prey selection or susceptibility to attack.  相似文献   

16.
17.
Summary

  • 1. A morphological study of five body regions of the Lepidoptera has been made, these being (a) the radial system of the mesothoracic wing, (b) the mesothoracic sternopleural region, (c) the ventral thoraco-abdominal articulative (and adjacent) structures, including the integumental components of the tympanum where present, (d) the dorsal thoraco-abdominal articulation, etc., and (e) the metathoracic furca or endosternite. These regions were selected because the nature of the variation they exhibit suggested that, of the much larger number of regions primarily investigated, they are the most likely to provide information on the evolution of the higher taxa in the order. None of these regions had been investigated at all fully previously, and therefore a considerable amount of basic morphological study was necessary as a preliminary to phylogenetic discussion. This morphological work has been extended to include the primitive Lepidoptera (with the Trichoptera) in the case of the mesosternopleural region, and in the regions of thoraco-abdominal articulation, in order to clarify basic homologies where these were obscure in the Ditrysia.

  • 2. Included also in the preliminary morphological treatment are two other body regions, the variation of which is not complex, and can be more briefly described. These regions are the prothoracic sclerites and the metanotal subdivisions—both of these showing interesting variation throughout the order which can be easily interpreted from the phylogenetic standpoint.

  • 3. Following reference to the basic morphology of each region studied, a broad outline of the evolutionary dynamics of each character complex is given in order to provide a basis for discussion of the evolutionary trends manifested within the superfamilies.

  • 4. In sections four and five of this work, the character complexes which were the subject of morphological study earlier are examined further with regard to their dynamics as manifested within each of the Ditrysian superfamilies. The formation of the concepts which are outlined here is based on consideration of all information derivable from all of these character complexes along with previously published information on other aspects of Lepidopterous anatomy. Resulting from this, a re-organization of the superfamilies has been possible on a phylogenetic basis. The chaotic state of the past literature on the classification of the Lepidoptera, the result of superficial taxonomic work, renders the comparison of the present system with previous ones clearly impossible within the scope of the present paper, but it is noted that many of the superfamily groupings do not differ very widely from those in some of the more comprehensive early studies, such as Forbes (1923). Through lack of material, no radical re-organization of the primitive Ditrysian superfamilies included in the Tinaeoid complex has been attempted, and for the same attempting to convey a very great deal of information by means of varied labelling of the two components of the suture. Reference both to the text, and to the figures given in the introductory (morphological) section of this paper, should however, enable anyone to appreciate these factors from the figures given. (3) Abbreviations used with reference to wing veins and pupal tracheae follow the standard Comstock-Needham system, apart from the identification of Cu2, which follows Tillyard's (1969) interpretation.

Note also that a few of the less common structures have been explained with the captions to the figures.  相似文献   

18.
《Journal of Natural History》2012,46(17):2183-2209
This paper reviews the Chinese species of Platyplectrus Ferrière. Twelve valid species are recognized from mainland China and a key to species is provided. Trichoplectrus Erdös (1951 Erdös, J, 1951. "Eulophidae novae. Acta Biologica". 1951, Academiae Scientiarum Hungaricae, 2(1–3), 169–237. [Google Scholar]) is newly synonymized with Metaplectrus Ferrière (1941 Ferrière, C, 1941. New species of Euplectrini (Hym. Chalcidoidea) from Europe, Africa and Asia, Bulletin of Entomological Research 32 (1941), pp. 1748.[Crossref] [Google Scholar]) and three new combinations are proposed: Metaplectrus szepligetii (Erdös) from Platyplectrus, Platyplectrus bussy (Crawford) from Euplectrus and P. politus (Lin) from Metaplectrus. Four species of Platyplectrus were known previously from China: P. politus (Lin), P. odontogaster (Lin), P. papillata Lin and P. medius Zhu and Huang. Six species, P. bussyi (Crawford), P. laeviscuta (Thomson), P. natadae Ferrière, P. orthocraspedae Ferrière, P. pannonica (Erdös) and P. viridiceps (Ferrière) are newly recorded from China and re-described. Five new species, P. pulcher, P. setulosus, P. peculiaris, P. obtusiclavatus and P. variflagellum are described and compared with related species. Several species are also newly recorded from other regions: P. orthocraspedae Ferrière from the Afrotropical region, P. bussyi (Crawford) and P. laeviscuta (Thomson) from the Australian/Pacific region, P. laeviscuta (Thomson) from the Oriental region and P. viridiceps from the Palearctic region.  相似文献   

19.
《Journal of Natural History》2012,46(21-22):1359-1367
We present data on predatory behaviour in Deltochilum cupreicolle viridescens, which belongs to the subgenus Aganhyboma, and we contrast it with the behaviour of a species from the subgenus Deltohyboma. By this comparison we can investigate whether the predatory behaviour in Deltochilum could have appeared independently in these two subgenera, or if the behaviour is so similar that it suggests a single origin in a possible ancestor exclusive to those two groups. These laboratory studies on the behaviour of Deltochilum c. viridescens individuals on diplopods are described and divided into the following stages: (1) approach and recognition of the diplopod; (2) attack and death of the prey; (3) on-site feeding; (4) transport of the diplopod. The results found here strengthen the hypothesis of a primitive and highly specialized behaviour within a possible clade formed by the predatory species of Diplopoda.  相似文献   

20.
《Journal of Natural History》2012,46(10):1495-1502
A new troglobitic cixiid species, Oliarus hernandezi sp. n. is described from three lava tubes on the island of Floreana, Galápagos group. It is the first known obligately cavernicolous planthopper species from Galápagos. Notes on its ecology and distribution are given, and phylogenetic relationships to epigean Oliarus species from Galápagos are discussed.  相似文献   

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