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1.
Aquatic macroinvertebrates in drainage ditches may alter rates of nutrient cycling and decomposition of organic matter but have not been accounted for in studies of ditch biogeochemistry. We collected sediment cores from four pairs of field (intermittent) and collection (perennial) ditches on Maryland’s Eastern Shore monthly from March 2011 to February 2012 to determine how taxonomic and functional group composition varies among different ditch types. We identified 138 taxa and assigned them to functional groups according to trophic position and modes of burrowing. There was no difference in mean abundance of invertebrates (5821 ind./m2) between seasons or types of ditches, and species richness peaked in winter (20 taxa/site) compared to other seasons (15 taxa/site), but did not vary between ditch types. Assemblage composition differed between field and collection ditches, but functional group composition did not. Field ditches flow intermittently which may limit the assemblage to early colonists and taxa adapted to survive desiccation. The benthic macroinvertebrate assemblage was dominated by the collector–gatherer functional feeding group (83.6%) and burrowing taxa (97.1%). Bioturbation by burrowing macroinvertebrates is likely an important process contributing to ecosystem-scale functions of drainage ditches, including regulation of biogeochemical processes occurring at the sediment–water interface.  相似文献   

2.
Five new species of the amphipod genus Bogidiella are described from fresh groundwaters in Spain. No freshwater Bogidiellidae were known previously from the Iberian peninsula.Groundwater crustaceans of Spain, 3.Groundwater crustaceans of Spain, 3.  相似文献   

3.
Species distribution patterns are widely studied through species distribution models (SDMs), focusing mostly on climatic variables. Joint species distribution models (JSDMs) allow inferring if other factors (biotic interactions, shared phylogenetic history or other unmeasured variables) can also have an influence on species distribution. We identified current distributional areas and optimal suitability areas of three species of the solitary snail‐shell bee Rhodanthidium (Hymenoptera: Megachilidae), and their host gastropod species in the Iberian Peninsula. We undertook SDMs using Maxent software, based on presence points and climatic variables. We also undertook JSDMs for the bees and the snails to infer if co‐occurrence could be a result of biotic interactions. We found that the three bee species: (1) use at least five different species of Mediterranean snails; (2) use empty shells not only for nesting but also for sheltering when there is adverse weather and during the night; (3) have their most suitable areas in the eastern and southern Iberian Peninsula, mostly on limestone areas; and (4) have their optimal range under Mediterranean climatic values for the studied variables. There is positive co‐occurrence of Rhodanthidium with the gastropod species, especially with the snail Sphincterochila candidissima. The contribution of the environmental component to the co‐occurrence is less than that of the residual component in those cases, suggesting that: (i) the use of biotic resources (between Rhodanthidium and the gastropod species); (ii) shared phylogenetic history (between R. septemdentatum and R. sticticum); or (iii) unmeasured variables are largely responsible for co‐occurrence.  相似文献   

4.
We have analysed the Eco RI restriction pattern of rDNA of the newt Triturus vulgaris and of some other amphibian species by Southern blotting and hybridization with nick-translated Xenopus rDNA prepared from the recombinant plasmids pXlr11 and pXlr12 (21). After hybridization with r11, the 28S coding fragments become visible in two bands, a prominent one of 5.3 kb and a weak band of 5.9 kb representing about 8% of the 28S genes. The evidence obtained so far by additional digestions with Bam HI and Bgl II indicates that in this species and in Triturus helveticus the coding regions of the 5.9 kb fragments are interrupted by an insertion 0.6 kb in length located in a 1.6 kb Bgl II fragment at the 3' end of the Eco RI fragment, which we believe to be the first described in a vertebrate.  相似文献   

5.
The current Northern Hemisphere migration systems are believed to have arisen since the last glaciation. In many cases, birds do not migrate strait from breeding to non‐breeding areas but fly via a detour. All western European populations of red‐backed shrikes Lanius collurio are assumed to reach their southern African wintering grounds detouring via southeast Europe. Based on theoretical considerations under an optimality framework this detour is apparently optimal. Here, we use individual geolocator data on red‐backed shrikes breeding in Spain to show that these birds do indeed detour via southeast Europe en route to southern Africa where they join other European populations of red‐backed shrikes and return via a similar route in spring. Disregarding potential wind assistance, the routes taken for the tracked birds in autumn were not optimal compared to crossing the barrier directly. For spring migration the situation was quite different with the detour apparently being optimal. However, when considering potential wind assistance estimated total air distances during autumn migration were overall similar and the barrier crossing shorter along the observed routes. We conclude that considering the potential benefit of wind assistance makes the route via southeast Europe likely to be less risky in autumn. However, it cannot be ruled out that other factors, such as following a historical colonisation route could still be important.  相似文献   

6.
The properties of El Ni?o-Southern Oscillation (ENSO), such as period, amplitude, and teleconnection strength to extratropical regions, have changed since the mid-1970s. ENSO affects the regional climatic regime in SW Europe, thus tree performance in the Iberian Peninsula could be affected by recent ENSO dynamics. We established four Quercus robur chronologies of earlywood and latewood widths in the NW Iberian Peninsula. The relationship between tree growth and the Southern Oscillation Index (SOI), the atmospheric expression of ENSO, showed that only latewood growth was correlated negatively with the SOI of the previous summer-autumn-winter. This relationship was non-stationary, with significant correlations only during the period 1952-1980; and also non-linear, with enhanced latewood growth only in La Ni?a years, i.e. years with a negative SOI index for the previous autumn. Non-linear relationship between latewood and SOI indicates an asymmetric influence of ENSO on tree performance, biassed towards negative SOI phases. During La Ni?a years, climate in the study area was warmer and wetter than during positive years, but only for 1952-1980. Winter temperatures became the most limiting factor for latewood growth since 1980, when mean regional temperatures increased by 1°C in comparison to previous periods. As a result, higher winter respiration rates, and the extension of the growing season, would probably cause an additional consumption of stored carbohydrates. The influence of ENSO and winter temperatures proved to be of great importance for tree growth, even at lower altitudes and under mild Atlantic climate in the NW Iberian Peninsula.  相似文献   

7.
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   

8.
The timing of pollen appearance in the atmosphere provides a general idea of the flowering onset of plants over a wide area. Woody plants in temperate regions have evolved mechanisms to preserve cells from the risk of frost during adverse weather conditions in the period prior to flowering regulated mainly by temperature. A number of indices have been developed to quantify the rest and heat requirements of temperature, which will enable the plant to adapt to environmental conditions. However, flowering is a dynamic and complex phenomenon and it is difficult to separate individual effects of different meteorological parameters. The use of modified bioclimatic indices could be a major step forward. In this study the Alnus glutinosa flowering in four different areas in north‐western Spain in the period 1995–2003 is examined, and trends identified by means of information gathered by Hirst pollen traps. Temperature plays an important role in the maturation of reproductive organs and pollen production. Comparison with bioclimatic indices showed that temperature during the 25–55 days preceding pollen release was the main controlling factor, and that relationship between flowering time and bioclimatic indicator values differs according to local conditions. In colder areas, rest and heat temperature requirements are greater because the trees need protection over a longer period; in the Mediterranean region of north‐western Spain, the rest temperature requirement and the threshold temperature are both higher than in Eurosiberian areas. Ombrothermic, Continentality and Thermicity indices are thus useful tools for characterizing the various bioclimatic areas of north‐western Spain.  相似文献   

9.
Biological invasions cause great damage to native ecosystems, therefore, it is extremely important to take measures to contain the progress of existing invasions and prevent new ones. Here, we used the Species Distribution Models approach to compare two independent datasets for the invasive alien species the Yellow-legged hornet in the Iberian Peninsula. One dataset compiles occurrence records gathered by expert people (e.g. environmental services’ technical staff and researchers); and the other compiles occurrence records gathered by non-expert people (e.g. amateur entomologists, beekeepers). The main aim is to assess the effectiveness and reliability of the dataset managed by non-experts when comparing it to the dataset managed by experts. Our results showed a high degree of concordance and similarity between models. Thus, both datasets would have the same reliability to be used in management strategies for this species.  相似文献   

10.
《Comptes Rendus Palevol》2016,15(5):581-594
Understanding the changes in the technological organization of prehistoric hunter–gatherers is important to research into hominin foraging activities. During the Middle Paleolithic, the coexistence or the replacement between Levallois and discoid technologies has frequently been recorded, but there is still no clear understanding of the reasons for their alternating and fragmented use in the archaeological record. This paper aims to contribute with new data to the current debate, by exploring the chert assemblages from levels O and M of the Abric Romaní rock-shelter. The results reveal that the change from Levallois in level O to discoid in level M is accompanied by the use of different axes of mobility, a reduction in the foraging radius and a more careful management of raw materials. A cross comparison with other archaeological evidences indicates the general pattern in the Northeast of the Iberian Peninsula during the late Middle Paleolithic, in which the use of Levallois technology is associated with chert and high mobility patterns whereas discoid technology is more closely linked to the use of local raw materials and a lower degree of mobility. The modifications to the mountainous environments and to the distribution of preferred prey animals may have influenced the Neanderthals’ mobility patterns and contributed to modifying their technical behaviours in order to obtain better foraging incomes.  相似文献   

11.
Vilà-Cabrera  Albert  Espelta  Josep Maria  Vayreda  Jordi  Pino  Joan 《Ecosystems》2017,20(1):130-143
Ecosystems - Land-use changes are one of the major drivers of global change. In many developed countries socioeconomic changes have induced forest expansion during the last centuries, with still...  相似文献   

12.
《Comptes Rendus Palevol》2016,15(8):958-967
We have analyzed the palaeoenvironment and palaeoclimate of the beginning of the Holocene in the Iberian Peninsula on the basis of the small-mammal assemblages from three sites within the geography of the Iberian Peninsula: Mirador (Sierra de Atapuerca, Burgos), Colomera (Sant Esteve de la Sarga, Lleida) and Valdavara-1 (Becerreá, Lugo). These associations reveal that the palaeoenvironment was more humid than today in the sites under study, and the landscape was dominated by woodland and woodland margins in all the studied layers. Further, the climatic conditions were stable, but with winters colder than at present, above all in the Mediterranean area. Finally, our data have been compared with other environmental and climatic proxies, showing that human activities exerted little impact on the palaeoenvironmental conditions that occurred from 7000 to 3000 BP in the Iberian Peninsula.  相似文献   

13.
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   

14.
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   

15.
Cross-breeding between wild and free-ranging domestic species is one of the main conservation problems for some threatened species. The situation of wildcats (Felis silvestris silvestris) in Europe is a good example of this critical phenomenon. Extensive hybridization was described in Hungary and Scotland, contrasting with occasional interbreeding in Italy and Germany. First analyses in Portugal revealed a clear genetic differentiation between wild and domestic cats; however, four hybrids were detected. Here, we extended the approach to Iberian Peninsula using multivariate and Bayesian analyses of multilocus genotypes for 44 Portuguese wildcats, 31 Spanish wildcats and 109 domestic cats. Globally, wild and domestic cats were significantly differentiated (FST=0.20, p<0.001) and clustered into two discrete groups. Diverse clustering methods and assignment criteria identified an additional hybrid in Portugal, performing a total of five admixed individuals. The power of admixture analyses was assessed by simulating hybrid genotypes, which revealed that used microsatellites were able to detect 100, 91 and 85% of first-generation hybrids, second-generation genotypes and backcrosses, respectively. These findings suggest that the true proportion of admixture can be higher than the value estimated in this study and that the improvement of genetic tools for hybrids detection is crucial for wildcat conservation.  相似文献   

16.
Migrating long distances requires time and energy, and may interact with an individual's performance during breeding. These seasonal interactions in migratory animals are best described in populations with disjunct nonbreeding distributions. The black‐tailed godwit (Limosa limosa limosa), which breeds in agricultural grasslands in Western Europe, has such a disjunct nonbreeding distribution: The majority spend the nonbreeding season in West Africa, while a growing number winters north of the Sahara on the Iberian Peninsula. To test whether crossing the Sahara has an effect on breeding season phenology and reproductive parameters, we examined differences in the timing of arrival, breeding habitat quality, lay date, egg volume, and daily nest survival among godwits (154 females and 157 males), individually marked in a breeding area in the Netherlands for which wintering destination was known on the basis of resightings. We also examined whether individual repeatability in arrival date differed between birds wintering north or south of the Sahara. Contrary to expectation, godwits wintering south of the Sahara arrived two days earlier and initiated their clutch six days earlier than godwits wintering north of the Sahara. Arrival date was equally repeatable for both groups, and egg volume larger in birds wintering north of the Sahara. Despite these differences, we found no association between wintering location and the quality of breeding habitat or nest survival. This suggests that the crossing of an important ecological barrier and doubling of the migration distance, twice a year, do not have clear negative reproductive consequences for some long‐distance migrants.  相似文献   

17.
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19.
Here, we report on an isolated pliopithecid M3/ (IPS35028) from locality ACM/C3-B2 (12.0 Ma, MN7) of the late Middle Miocene stratigraphic series of Abocador de Can Mata (ACM, Vallès-Penedès Basin, NE Iberian Peninsula). This tooth is about 0.2 million years older than the remains of Pliopithecus canmatensis (11.8-11.7 ma), recorded from several localities from the ACM series. The unusual occlusal features of IPS35028, together with the lack of homologous material for several pliopithecid species, preclude a precise taxonomic attribution of the C3-B2 specimen, which does not fit the morphology of any known pliopithecid M3/. In particular, although an attribution to P. canmatensis would seem reasonable on the basis of size, identical geographic provenance, and similar age, the morphology of IPS35028 appears too primitive compared to the M1/ and M2/ of the former taxon. Instead, the C3-B2 pliopithecid displays several primitive features shared with the dionysopithecine Dionysopithecus and the pliopithecine Pliopithecus piveteaui. It therefore seems more likely that IPS35028 represents a previously unknown pliopithecid taxon, although a formal taxonomic recognition of its probable distinct status is not advisable, given the scarcity of the currently available material. Alternatively, this taxon might be more closely related to small-bodied African catarrhines (such as dendropithecids). However, the morphology of the ACM specimen is not particularly similar to that of the M3/ of these African taxa. Hence, based on age and geographic provenance, an attribution of IPS35028 to the Pliopithecidae is favored here.  相似文献   

20.
Anthropomorphism (and its obverse, zoomorphism) continues to shift and propel us toward changing perspectives on ourselves and other animals. Discussions of anthropomorphism in primate behavior are ostensibly about our use and definition of terms, but ultimately reflect our views of what is unique to humans or unknowable in other animals. Primatologists doing long-term fieldwork report on the bonds that are inevitably formed through familiarity with their study subjects and how anecdotes and anthropomorphism help them to gain a contextualized view of animal lives. This fuller view of animal society serves as an aid to understanding different rationalities and provides a more effective modern role for anthropomorphism than does seeking to demonstrate isomorphic capacities in alloprimates. Although most ordinary language terms are accepted among primatologists, "primate culture" serves as an example of a term and a concept that overreached acceptable anthropomorphic limits when defined to accord with definitions of modern human culture. Comparing similar behavioral forms as the product of similar selective pressures acting on specific early traits, producing homoplasies through convergent evolution, provides a nonanthropomorphic basis for seeking similarities in human and alloprimate behavior.  相似文献   

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