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1.
《Acta Oecologica》1999,20(4):429-434
We studied the composition, density, size distribution and biomass of the food supply for waders in an estuarine area in the Bay of Cádiz (SW Iberian Peninsula), in winter (January-February) and in the pre-migratory period (late March). The estuarine area comprises an intertidal mudflat and an adjacent salina or salt-pan. On the intertidal mudflat, the biomass was 53 and 37 g  AFDW.m-2in winter and the pre-migratory period, respectively. The main food source on mudflat was the polychaete Nereis diversicolor (44–54 % of the total biomass). On the other hand, the biomass in the salina was comparatively very poor, ranging from 0.008 to 0.079 g  AFDW.m-2in winter and ranging from 0.011 to 0.09 g AFDW in late March. The main source of food in the salina was the crustacean Artemia. The total biomass on the mudflat during the pre-migratory period was 1.4 times lower than in February. This depletion could be caused by wader predation, mainly by Nereis diversicolor consumption. Although the potential food on the mudflats could allow high intertidal densities of waders, the availability of high tide foraging areas in the salina seems to contribute to the maintenance of these high intertidal densities.  相似文献   

2.
The entire sequence of the mitochondrial cytochrome b gene and 2 partial sequences of the ribosomal RNA12S and 16S genes have been used to study the molecular phylogeny in 10 species of soles belonging to the genera Solea, Monochirus, Microchirus, Dicologlossa, and Synaptura from the Atlantic waters of the Gulf of Cádiz (Spain). The results obtained by means of different phylogenetic analyses (maximum likelihood, maximum parsimony, and neighbor-joining) were quite similar, supporting the monophyly of the Solea species. Nevertheless, they favor the differentiation of Dicologlossa cuneata and Dicologlossa hexophthalma in 2 distinct genera, since the most closely related species to the last one is Microchirus azevia. The fact that M. azevia is also more closely linked to Monochirus hispidus than to its congeneric Microchirus boscanion argues in favor of a taxonomic reorganization of these genera.  相似文献   

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4.
Three new Annitella species (Trichoptera, Limnephilidae, Chaetopterygini) from the Iberian Peninsula, Annitella amelia sp.n. (Portugal), A. cabeza sp.n. (Spain) and A. lalomba sp.n. (Spain) are described. Psilopteryx (Acropsilopteryx) esparraguera Schmid, 1952 and Psilopteryx sanabriensis Gonzales and Otero, 1985 are transferred to the genus Annitella. Brief decriptions and illustrations of these species and of the related species A. pyrenaea (Navás, 1930) are given. A sketch map of the distribution of the Annitella species in the Iberian Peninsula is included.  相似文献   

5.
The composition of the microbial community inhabiting the anoxic coastal sediments of the Bay of Cádiz (southern Spain) was investigated using a molecular approach consisting of PCR cloning and denaturing gradient gel electrophoresis (DGGE), based on 16S rRNA sequences. The total cell count was 1-5 × 10? cells/g sediment and, as determined by catalyzed reporter deposition-fluorescent in situ hybridization (CARD-FISH), the proportion of Bacteria to Archaea was about 70:30. The analysis of 16S-rRNA gene sequences revealed a wide spectrum of microorganisms, which could be grouped into 111 operational taxonomic units (OTUs). Many of the OTUs showed high phylogenetic similarity to microorganisms living in marine sediments of diverse geographic origin. The phylogenetic groups that were predominantly detected were Firmicutes, Deltaproteobacteria, and Gammaproteobacteria, accounting for 23, 15, and 14% of the clones, respectively. Diversity in the domain Archaea was significantly lower than in the domain Bacteria. The majority of the archaeal OTUs belonged to the Crenarchaeota phylum. Since most of the sequences could not be identified precisely at the genus/species level, the functional roles of the microorganisms in the ecosystem could not be inferred. However, seven OTUs affiliated with the Delta- and Epsilonproteobacteria were identified down to the genus level, with all of the identified genera known to occur in sulfate-rich marine environments.  相似文献   

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7.
Russian Journal of Marine Biology - This article provides results of a helminthological study of two seabird species, the Black-Legged Kittiwake (Rissa tridactyla Linnaeus, 1758) and the...  相似文献   

8.
Currently, it has been observed that a considerable segment of the jaguar population is declining mainly because of hunting, and destruction and fragmentation of habitat. Given this scenario, efforts of the scientific community have been concentrated on the development of conservation strategies, such as the formation and use of somatic sample banks. We aimed to assess the effects of cryopreservation techniques of the ear skin of jaguar [slow freezing (SF) or direct vitrification in cryovials (DVC) or solid-surface vitrification (SSV)] on the morphological analysis and cell ability during the culture. All cryopreserved fragments regardless of the technique used, showed a reduction in the dermis and total thickness of the skin. Although a collagen matrix similar to the control group (fresh) has been observed only for the fragments from SF and SSV groups, all cryopreserved techniques were able to maintain normal patterns of the fibroblasts. Moreover, DVC and SSV methods maintained the proliferative activity of the tissues even after warming. After the culture, SF and SSV techniques were efficient for the recovery of the somatic cells according to most of the evaluated parameters, especially with regard to the duration of culture and cell metabolic activity. In conclusion, SSV was found to be a more efficient technique for cryopreserving jaguar skin when compared to DVC and SF. These results are relevant for the formation of somatic resource banks of this species, directed at cryopreserving adequate samplings of different individuals and generations for future applications in regenerative medicine, and assisted reproductive technologies.  相似文献   

9.
Three field predator exclusion experiments were conducted in 1992 on a lagoonal muddy pan of the Bay of Cádiz to measure the effects of large epibenthic predators (fish and crustacean decapods) on the benthic macroinvertebrate community at different periods of the year (May–June, August–September, November–December). At the end of each field experiment (30–31 days), benthic macrofaunal communities within exclosures and control plots (three replicates for each treatment) were compared. There were no considerable exclosure artifacts in all three experiments, but a great heterogenity in the spatial macrofaunal distribution was observed especially in the late autumn experiment. No systematic change in overall faunal characteristics was observed with the exclusion of epibenthic predators, except significantly greater mean individual sizes (all experiments) and lower total densities (June and December) within exclosures. For several benthic species, a statistically detectable increased density and larger mean individual size were also observed within exclosures in May–June and August–September experiments but not in December, probably related to the higher predatory activity during the warm season. Conversely, the amphipod Microdeutopus gryllotalpa showed lower density but also larger mean size when epibenthic predators were excluded. An algal cover (Ulva) was present at three field experiments and had a mixed effect on the density of benthic macrofauna. Some epifaunal species (or epifaunal stages) were positively affected by the algal biomass, while some infaunal species were negatively affected.  相似文献   

10.
Environmental Biology of Fishes - To clarify the reproductive activity of lane snapper, Lutjanus synagris, a total of 359 specimens of lane snapper were collected in partnership with an artisanal...  相似文献   

11.
We assess the genetic history and population structure of Cicada barbara in Morocco and the Iberian Peninsula, based on analysis of the mitochondrial cytochrome b gene. The divergence between Morocco and the Iberian Peninsula populations was strongly corroborated by the molecular data, suggesting genetically isolated populations with a low level of gene flow. The Ceuta population from Spanish North Africa was more similar to the Iberian populations than the surrounding Moroccan populations, suggesting that the Strait of Gibraltar has not been acting as a strict barrier to dispersal while the Rif Mountains have. The Iberian Peninsula specimens showed a signature of demographic expansion before that which occurred in Morocco, but some of the assumptions related to the demographic parameters should be considered with caution due to the small genetic variation found. The high haplotype diversity found in Morocco implies higher demographic stability than in the Iberian Peninsula populations. These results do not, however, suggest a Moroccan origin for Iberian cicadas; but the most northwest region in Africa, such as Ceuta, might have acted as a southern refuge for Iberian cicadas during the most severe climatic conditions, from where they could expand north when climate improved. The separation of two subspecies within C. barbara (C. barbara lusitanica and C. barbara barbara) finds support with these results.  相似文献   

12.
The epidemiology of Ancylostoma spp. was studied in the endangered Iberian lynx (Lynx pardinus) in the Do?ana National Park, south-west Spain. Faecal samples were collected throughout a complete annual cycle (August 1997 to September 1998). The overall egg prevalence of Ancylostoma spp. was 57.8%. The pattern of abundance of Ancylostoma spp. eggs in faeces was overdispersed. Juvenile lynx demonstrated a statistically higher prevalence and abundance of Ancylostoma spp. than in adults. These levels of egg output (maximum 21195 epg), as previously reported in free ranging large felid cubs, could be close to disease involvement. The potential pathogenicity of hookworms and the influence of individual and ecological factors on hookworm transmission in the Iberian lynx from the Do?ana National Park population are discussed.  相似文献   

13.
Aquatic Ecology - Considerate the attitudes of traditional communities and their local ecological knowledge (LEK) can contribute to better policymaking and more appropriate management plans. Thus,...  相似文献   

14.
The ascidian Ecteinascidia turbinata synthesizes some of the most promising substances against solid-type tumors, but the only available source are the natural populations of this tunicate, which is reared or collected in different parts of the world. A total of 33 locations were sampled in the Gulf of Mexico and the Yucatan Peninsula. The tunicate was not found in Veracruz, Tabasco and Campeche, but it was well established on mangrove roots in the Yucatan Peninsula where we estimated densities more or less equal to one colony and an average production of 115 g of biomass per lineal meter of mangrove coastline in one location (Río Lagartos). Sustainable management appears to be possible.  相似文献   

15.
Mollet Cave is a small cave situated in Serinyà (north-east Iberian Peninsula). It was excavated in 1947-48, 1958 and 1972 by Josep M. Corominas. An archaic human molar comes from its base layer (Layer 5). Up till now, this layer has only been dated based on a relative and imprecise chronology of macromammals and the archaeostratigraphic evidence from the early excavations. Recent excavations, conducted between 2001 and 2005, have made it possible to ascertain more precisely the archaeological and palaeontological contents of Mollet Cave, gather microvertebrates, and collect samples for radiometric dating. The aim of this paper is to present the absolute dating of Layer 5, as well as its palaeo environmental and climatic characterisation. The macromammal assemblage seems to have been the result of accumulations produced by the most abundant carnivore, the hyena, which would have used the cave as a den. The results obtained using uranium-series disequilibrium dating ascribe to Layer 5 an age of ca. 215 ka (thousands of years ago), which would correspond to MIS 7. The faunal association suggests a landscape formed by an open and humid woodland characteristic of an interstadial phase, which would have been an environment well suited to sustaining both hyenas and human groups.  相似文献   

16.
Analyses of the pigmentation stages and the size of glass eels during the arrival period to two northwestern Iberian estuaries (Ríos Nalón and Minho) and comparison of the patterns elucidated in this study with those reported for other geographical locations of the Atlantic and Mediterranean ranges showed nine pigmentation stages ranging from practically transparent to fully pigmented in the two-first locations. Overall, stage VB was predominant but within a broad variance across rivers and seasons. Consistent with previous studies, pigmentation stages tended to increase when the season progressed whilst, for a given individual length, mass tended to be higher during the early months of arrival. Moreover, both mass and condition factor were lower in individuals of advanced stages. Whilst we found no significant differences on glass eels length among pigmentation stages, both mass and condition factor were lower in more pigmented individuals. Given that larger glass eels with better physical condition may reveal greater energy content implying improved upstream migration earlier individuals may be better migrants than latter individuals.  相似文献   

17.
Field recordings of the calling song and of an amplitude modulated signal produced by males of Cicada barbara from North Africa and the Iberian Peninsula were analysed in order to assess the geographical acoustic variation and the potential usefulness of acoustic data in the discrimination of subspecies and populations. Sound recordings were digitized and the frequency and temporal properties of the calls of each cicada were analysed. In all regions studied, peak frequency, quartiles 25, 50 and 75% and syllable rate showed low coefficients of variation suggesting inherent static properties. All frequency variables were correlated with the latitude, decreasing from south to north. In addition, most acoustic variables of the calling song showed significant differences between regions, and PCA and DFA analyses supported a partitioning within this species between Iberian Peninsula+Ceuta and Morocco, corroborating mtDNA data on the same species. Therefore, the subspecific division of C. barbara into C. barbara barbara from Morocco and C. barbara lusitanica from Portugal, Spain and Ceuta finds support from the present acoustic analyses, a result which is also reinforced by molecular markers.  相似文献   

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Statolith trace elemental concentrations can be used as natural tracers to better understand life history and stock structure of squid. A highly variable Humboldt squid population was targeted to determine if ontogenic patterns could be revealed and to compare variations among squid collected from three geographic areas. Statoliths from Humboldt squid collected off Westport, WA; Oceanside, CA; and the Galapagos Islands were sampled for ten trace elements using laser ablation inductively coupled plasma mass spectrometry. Similar patterns were found for some elements despite geographic collection site distances indicating a potential to explain ontogenic shifts experienced by this species. Other elements displayed high variation in spatial pattern, which suggests the potential to distinguish among the squid collected from the three geographic regions and better understand stock structure. Within the California and Washington squid, eight of the elements varied in relation to calcium across the statolith with only yttrium and zirconium remaining statistically invariant. In addition to these two elements, copper and zinc also did not vary significantly across the statoliths collected from Galapagos squid. All elements demonstrate potential to influence a multivariate elemental fingerprint, which may provide a useful measure of population discrimination needed for stock assessment.  相似文献   

20.
This study is part of the Restoration Program of the animal populations from the Guadiamar River basin. The main objective is to evaluate the current state of populations of the most representative groups of edaphic coleoptera in the Guadiamar River basin. In 1998, a breach in the Aznalcóllar mines retaining wall (Southern Iberian Peninsula) led to toxic sludge pouring out into this area. Systematic samples were taken from monitoring plots, scattered throughout the affected area. In order to provide an overall assessment of the fauna collected from this area in relation to adjacent areas, ecological indices were applied, and temporal course and biogeographical comparisons were also made. The results indicate that, overall, the edaphic fauna has not been significantly affected by the spillage; however, a faunistic poverty was also detected, which becomes increasingly evident closer to the accident site. Moreover, temporal evolution analysis suggests that the most affected areas are undergoing a re-colonization process, although this varies widely between species and higher taxa. This research has been financed by the Project ‘Caracterización, restauración y conservación de las comunidades animales de la cuenca del río Guadiamar’ (Characterization, Re-establishment and Conservation of the animal communities from the Guadiamar River basin). Consejería de Medio Ambiente. Junta de Andalucía (Spain).  相似文献   

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