首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 921 毫秒
1.
Lembo  G.  Spedicato  M. T.  Økland  F.  Carbonara  P.  Fleming  I. A.  McKinley  R. S.  Thorstad  E. B.  Sisak  M.  Ragonese  S. 《Hydrobiologia》2002,483(1-3):249-257
The value of marine reserves to protect threatened and vulnerable species, such as the dusky grouper (Epinephelus marginatus), is often uncertain because of a lack of knowledge about their ecology and habitat utilisation. To address this issue, a Wireless Communication System for location-based positioning of fish tagged with coded acoustic transmitters was installed to determine site fidelity of juvenile dusky groupers (mean total length = 30.4 cm, range: 20.5–40.0 cm; mean total weight = 470 g, range: 113–950 g) within a marine reserve (Island of Ustica, Sicily, Italy). The system was based on five wireless hydrophones distributed approximately 200 m apart along the coastline of the reserve, each monitoring acoustic signals from transmitters within a reception cell. The hydrophones retransmitted detected signals as a radio signal to a land-based receiver and data logger. Unique identifiers for each hydrophone permitted the identification of the detection cell containing the tagged fish. The wireless hydrophones had partly overlapping detection ranges, dividing the marine reserve into more than five different detection cells. The average detection range was 232 m, but coverage varied from site to site and with time, depending on many factors, such as ambient noise, wave action and signal strength of the transmitters. Despite some limitations, the Wireless Hydrophone System (WHS) combined with manual tracking provided a valuable tool for investigating site fidelity in the dusky grouper. Preliminary home ranges for the fish were estimated by the kernel method (probability level of 95%), based on a limited set of manual tracking data, to be a median 5312 m2 (range 1673–18626 m2).  相似文献   

2.
New anthracotheriid remains, discovered by the H-GSP in well-dated localities from the Potwar plateau in the North of Pakistan, between 10.4 and 8.6 Ma, are described and attributed to Merycopotamus medioximus nov. sp. This new species displays an intermediate morphology between the older M. pusillus and the more recent M. dissimilis. These results permit to emend the Merycopotamus diagnosis. To cite this article: F. Lihoreau et al., C. R. Palevol 3 (2004).

Résumé

Une nouvelle espèce d'Anthracotheriidae, Merycopotamus medioximus nov. sp. du Miocène récent du plateau du Potwar, Pakistan. Des restes d'Anthracotheriidae, découverts par le H-GSP dans des localités bien datées du plateau du Potwar, au Nord du Pakistan, entre 10,4 et 8,6 Ma, sont décrits et attribués à Merycopotamus medioximus nov. sp. Cette nouvelle espèce possède une morphologie intermédiaire entre M. pusillus, espèce plus ancienne, et M. dissimilis, plus récente. Ces résultats permettent en outre d'émender la diagnose du genre Merycopotamus. Pour citer cet article : F. Lihoreau et al., C. R. Palevol 3 (2004).  相似文献   

3.
The potential of alleviated fishing pressure measures established at the Marine Natural Reserve of Cerbère-Banyuls to affect phenological characters of P. oceanica, the main canopy-forming seagrass, was studied. Our results show differences in some leaf parameters between meadows under fishing prohibition measures compared to those without. In addition shallow P. oceanica meadows inside MPAs had lower non-structural carbohydrate content, yet are able to maintain themselves and, moreover, with an increased density. On the other hand, sexual reproduction was reduced inside protected areas.  相似文献   

4.
5.
Diet, habitat use and relative abundance of pampas fox Pseudalopex gymnocercus were studied in grassland, sand dune, and scrubland habitats, on the Bahía San Blas and Isla Gama Reserve, Argentina. Scat contents showed a generalist diet, where mammals, insects, and fruits were the main food items. Dietary composition differed among habitats; fruits were mainly consumed in sand dunes; insects, mammals, and fruits predominated in grassland; while insects and mammals were frequent in scrubland habitat. The European hare was the most common vertebrate prey and had the major contribution to the biomass of consumed prey. Pampas fox was the most common carnivore of the reserve and used all available habitats, frequenting more regularly scrubland and sand dune than grassland habitat.

Zusammenfassung

Nahrung, Habitatnutzung und relative Abundanz von Pampasfüchsen (Pseudalopex gymnocercus) im nördlichen Patagonien, Argentinien Die Nahrung, Habitatnutzung und relative Abundanz von Pampasfüchsen Pseudalopex gymnocercus wurde auf Grasflächen, Sanddünen und in Strauchhabitaten des Bahía San Blas and Isla Gama Reserve, Argentinien untersucht. Die Analyse von Kotproben ergab eine typische Diät für Generalisten, wobei Säugetiere, Insekten und Früchte die wichtigsten Nahrungsbestandteile waren. Die Nahrungszusammensetzung unterschied sich zwischen verschiedenen Lebensräumen. Früchte wurden hauptsächlich in Sanddünen konsumiert, Insekten, Säugetiere und Früchte auf Grasflächen; und Insekten und Säugetiere in Strauchhabitaten. Der europäische Hase war die häufigste Beuteart unter den Wirbeltieren und stellte den Hauptanteil an der Biomasse genutzter Beute. Der Pampasfuchs ist das häufigste Raubtier im Reservat und nutzt alle vorhandenen Habitate, jedoch kommt er etwas häufiger in Strauchhabitaten und Sanddünen vor als auf Grasflächen.  相似文献   

6.
7.
Three genera of hyracoids were recorded from the Early Miocene of East Africa by Whitworth [18], but there has been considerable divergence of opinion about their status. Despite differences in cranial and dental morphology from Megalohyrax and Bunohyrax, Whitworth [18] classified two species in these genera that are recorded from much earlier deposits (Early Oligocene) in the Fayum, Egypt. One of his genera (Meroehyrax) was new. His classification has been the subject of debate, with some researchers [6,13] doubting the hyracoid status of one of his species (Bunohyrax sp), and changing the generic status of another (Megalohyrax championi). Meyer [6] recorded a fourth genus (Prohyrax) from Kenya, linking it to material from Namibia described by Stromer [16,17]. New samples of two hyracoid species collected by the Uganda Palaeontology Expedition throw light on their systematic position and taxonomy. It is concluded that there are three hyracoid genera (Afrohyrax, Brachyhyrax and Meroehyrax) in the Early Miocene deposits of East Africa, the first two of which are new. A fourth genus (Prohyrax) occurs in southern Africa, but is not reliably known from East Africa. To cite this article: M. Pickford et al., C. R. Palevol 3 (2004).

Résumé

Révision des Hyracoidea (Mammalia) du Miocène inférieur de l'Afrique de l’Est. Trois espèces d’Hyracoidea ont été signalées dans le Miocène inférieur d’Afrique orientale par Whitworth [18]. Malgré des différences importantes de la morphologie cranio-dentaire, deux des espèces kenyanes étaient classées dans Megalohyrax et Bunohyrax, genres connus dans les dépôts beaucoup plus anciens du Fayoum en Égypte. Le troisième genre décrit par Whitworth (Meroehyrax) était nouveau. La classification proposée [18] a été débattue ; certains auteurs [6,13] ont remis en cause le statut d’Hyracoïde d’une de ses espèces et ont modifié le statut générique d’une autre. Meyer [6] a signalé un quatrième genre (Prohyrax) au Kenya, sur la base des ressemblances avec le genre namibien décrit par Stromer [16,17]. De nouveaux spécimens récoltés par l’Uganda Palaeontology Expedition permettent d’éclaircir la position systématique et la taxonomie de deux des espèces. Nous concluons qu’il n’existe que trois genres d’Hyracoïdes dans les dépôts du Miocène inférieur d’Afrique orientale (Afrohyrax, Brachyhyrax et Meroehyrax), dont les deux premiers sont nouveaux. Par ailleurs, un quatrième genre (Prohyrax) est connu d’Afrique australe. Pour citer cet article : M. Pickford et al., C. R. Palevol 3 (2004).  相似文献   

8.
I collected baseline abundance data on groupers from the reefs of Vavanga village on Kolombangara Island, Solomon Islands. Physical and environmental factors significantly affected the abundance and distribution patterns of groupers. Size and age distribution of groupers varied with depth. Power analysis on the abundance data showed that although power could be calculated to within an acceptable level from a management perspective for abundant species such as the coral hind, Cephalopholis miniata, the same could not be done for larger and naturally scarce species, such as the humpback grouper, Cromileptes altivelis.  相似文献   

9.
The study of well-preserved Pliocene and Pleistocene s from Emi from Emilia is used to analyze the morphological variations of Mediterranean populations, to depict the relationship between fasciole shape and other morphological characteristics and to describe previously unpublished pedicellar valves. These new data allow to be two species distinguished: s (Müller) a (Müller) and s Pomel; six s Pomel; six species closely related to s are synonymi are synonymized: s and it and s Pomel, i Pomel, i and itS. and s Checchia-R Checchia-Rispoli, x Simonelli a Simonelli and the recent species from Mediterranean, s Mortensen Mortensen. s can be disti can be distinguished from s by its hear by its heart-shaped subanal fasciole, when the s one is reni one is reniform. Moreover, the frontal groove of s is deeper, t is deeper, the primary tubercles of the interambulacra 1 and 4 are less numerous, the petals are shorter and narrower, the labrum is shorter. As far as pedicellariae are concerned, the jags of the large tridentate ones are stronger and the base of the globiferous ones is bigger. Palaeoecological observations on outcrops of the Stirone River, in Parme region, show similar environmental affinities between fossil populations and recent populations from Mediterranean. The s fossils fossils seem to be preserved within their life environment, that is to say in shore sandy substrates.

Résumé

L'étude d'un groupe de spécimens bien conservés appartenant au genre Spatangus, trouvés, dans des localités pliocènes et pléistocènes de l'Émilie, permet d'exposer l'étendue de la variation dans les populations fossiles méditerranéennes, de rechercher les relations entre la forme du fasciole sous-anal et les autres caractères morphologiques et de décrire les valves des pédicellaires, qui n'étaient pas connues jusqu'alors. Ces nouvelles données conduisent à reconnaître deux espèces différentes : s (Müller) e (Müller) et s Pomel ; six Pomel ; six espèces voisines de s doivent prob doivent probablement tomber en synonymie : s et itS et s Pomel, i Pomel, i et itS. a et s Checchia-R Checchia-Rispoli, x Simonelli e Simonelli et l'espèce vivant actuellement en Méditerranée, s Mortensen Mortensen. Des observations paléoécologiques sur un échantillon fossile récolté sur les bords de la rivière Stirone près de Parme montrent des affinités bionomiques semblables chez les populations fossiles et celles vivant en Méditerranée.  相似文献   

10.
The discovery of a propotamochoerine suid with unique features of the dentition and skull led to the naming of Molarochoerus yuanmouensis Liu & Pan [6]. Further study of the material reveals that this species was better adapted than Sus scrofa for the ‘rooting’ behaviour and that its dentition has morphological features indicating that it was eating hard food items. The posterior premolars are completely molarised, hence the generic name, the first time that any suid has been shown to possess almost perfectly molariform P4/s and p/4s. In lateral view the curvature of the occlusal surface of the upper cheek teeth is convex ventrally, the opposite of the usual situation in suids. The origins of the rostral musculature are exceptionally well developed, and the nasal bones are much more robust than is usually the case in Suinae, indicating powerful musculature and fortified osseous structures presumably for ‘rooting’ in hard ground or for extended periods of time. The masseteric musculature appears to have been more massive than it is in Sus, Microstonyx and Propotamochoerus. To cite this article: M. Pickford et al., C. R. Palevol 3 (2004).

Résumé

Systématique et morphologie fonctionnelle de Molarochoerus yuanmouensis (Suidae, Mammalia) du Miocène supérieur de Yunnan, Chine. La découverte d”un Suidae Propotamochoerini présentant des caractères dentaires et crâniens uniques a conduit à la création de Molarochoerus yuanmouensis Liu & Pan [6]. Une étude du matériel montre que cette espèce était bien mieux adaptée au fouissage que Sus scrofa. Par ailleurs, les caractères morphologiques de sa dentition indiquent qu'il se nourrissait d'aliments coriaces. Les prémolaires postérieures sont complètement molarisées, d'où le nom générique, et c'est la première fois qu'un Suidae présente des P4 supérieures et inférieures presque parfaitement molariformes. En vue latérale, la courbure de la surface occlusale des dents jugales supérieures est convexe ventralement, différant ainsi de la morphologie classique des Suidae. La musculature rostrale est exceptionnellement bien développée et les os nasaux sont beaucoup plus robustes que chez les autres Suinae, suggérant des structures musculaires et osseuses puissantes, probablement liées au fouissage, soit dans des sols, soit sur une longue durée. Les muscles massétériens sont plus puissants que dans les genres Sus, Microstonyx et Propotamochoerus. Pour citer cet article : M. Pickford et al., C. R. Palevol 3 (2004).  相似文献   

11.
Synopsis The influence of habitat on the size distribution of groupers was examined at sites in the middle and upper Florida Keys. Transects were used to quantify the size distribution of groupers at study sites. There were significant differences in the size distribution of groupers within and among reef community types related to differences in species composition and patch reef size. Groupers with a giant life-history style (Sullivan & de Garine 1994) were more abundant, but smaller, on inshore patch reefs than offshore reef community types. However, grouper species with a dwarf life-history style (Sullivan & de Garine 1994) showed an opposite pattern with a lower abundance, but larger size, inshore than offshore. The length category of groupers constituting the majority of individuals observed on patch reefs was inversely related to reef size. Graysby Epinephelus cruentatus were shown to recruit to deeper (15–20 m), low-relief habitats offshore. Several factors influenced the size distribution of groupers in the study sites including habitat type, spear-fishing, competition, predation, and recruitment.  相似文献   

12.
The diet of the dusky grouper Epinephelus marginatus , from the Balearic Islands, western Mediterranean, consisted primarily of crustaceans, molluscs and fishes, but diet composition varied with body size. The smaller dusky groupers (<300 mm L T) fed primarily on crustaceans, and particularly on brachyurans, which accounted for 46% of the prey identified. As dusky groupers grew, cephalopods became increasingly important and constituted 10 to 40% of the prey identified in subadult and adult specimens. The largest dusky groupers fed primarily on fishes that represented 40·9% of prey identified. These shifts in diet were accompanied by a positive selection of increasingly large prey and by an expansion of trophic niche. δ 15N values of dusky grouper white muscle ranged from 8·8 to 13·1% and 71% of the variation in δ 15N was explained by differences in dusky grouper size. δ 13C values ranged from – 17·9 to – 15·9%, and no significant body size effect on δ 13C was detected. Stomach content and 13C values indicated that from 1 year old, the diet of E. marginatus was based on the benthic food web. The enrichment in δ 15N registered from juvenile to large males was c . 3·8%. Overall, there was good agreement between gut content and stable isotope data indicating that the latter may be useful as a tool in trophic studies in marine protected areas where sampling for fishes is not allowed.  相似文献   

13.
Synopsis Submersible dives were made on a site in the Gulf of Mexico 160 km southeast of Galveston, Texas in September 1984. Both yellowedge, Epinephelus flavolimbatus, and snowy grouper, E. niveatus, were observed utilizing shelter around rock ridge habitats. The yellowedge grouper also sought shelter within three types of burrows cut into soft sediment. Many of these burrows were significant excavations consisting of large trenches 7–8 m long, 2–3 m wide, and 1–1.5 m deep. Burrows were found in depths from 265 to 290 m. Tilefish, Lopholatilus chamaeleonticeps, also occur at this site, usually inhabiting the characteristic vertical burrows already described for this species. In four daytime submersible transects covering a linear distance of over 13000 m, we observed a total of 66 yellowedge groupers. Twenty-five were in burrows, 39 among rocks, and two over open bottom. It is suggested that this species may have an advantage over congeners that utilize only rocky habitat for cover. It may also compete for shelter with tilefish at depths where the two species overlap.Contribution No. 696, Harbor Branch Foundation, Inc. and Contribution No. 733, The University of Texas Marine Science Institute.  相似文献   

14.
We report the results of a census of Indri indri conducted in Betampona Nature Reserve, a lowland rain forest in eastern Madagascar. In addition, we conducted a year-long study of the ranging behavior of 3 groups in the southwestern region of the reserve. We used 2 methods to calculate population density and home range size, and to provide minimum and maximum estimates. Population density of Indri indri ranged from 6.9–13.2 individuals/km2 in Betampona. Mean home range size is 27 ha. The values for population density and home range size are intermediate between values for Indri indri in selectively logged and undisturbed montane rain forest. Our results suggest a relationship between habitat disturbance, population density and home range size for the species. Recent increases in habitat disturbance appear to cause an increase in population density and a decrease in home range size. The results are consistent with ones for other folivorous primate populations. Further research on habitat requirements of Indri and availability in Betampona is necessary to investigate the possibility of translocating Indri from nearby forest fragments into Betampona.  相似文献   

15.
Kelp grouper, Epinephelus bruneus, fed for 30 days with 0% (control), 0.1%, 1.0%, and 2.0% of Styrax japonica supplementation diets, led to reductions in mortality after being challenged with a bacterium (Vibrio harveyi) and a ciliate protozoan (Uronema marinum). The enriched diets significantly increased the survival rate as compared to the controls. The phagocytic and respiratory activities were significantly increased in kelp groupers given 1.0% and 2.0% enriched diets. The complement activity, lysozyme activity, serum bactericidal activity, and total protein level significantly increased with any enriched diet against the pathogens; however antiprotease activity and myeloperoxidase levels significantly increased only with 1.0% and 2.0% enriched diets while the α2-macroglobulin level was significantly enhanced with 1.0% enriched diet. The study suggests that incorporation of S. japonica at 1.0% and 2.0% level in the diet significantly enhances the immune responses in the kelp grouper E. bruneus against V. harveyi and U. marinum.  相似文献   

16.
Habitat size, habitat isolation and habitat quality are regarded as the main determinants of butterfly occurrence in fragmented landscapes. To analyze the relationship between the occurrence of the butterfly Cupido minimus and these factors, patch occupancy of the immature stages in patches of its host plant Anthyllis vulneraria was studied in the nature reserve Hohe Wann in Bavaria (Germany). In 2001 and 2002, 82 A. vulneraria patches were surveyed for the presence of C. minimus larvae. The occurrence was largely affected by the size of the food plant patches. In a habitat model that uses multiple logistic regression, the type of management and habitat connectivity are further determinants of species distribution. Internal and temporal validation demonstrate the stability and robustness of the developed habitat models. Additionally, it was proved that the colonization rate of C. minimus was significantly influenced by the distance to the next occupied Anthyllis patch. Concerning long-term survival of (meta-) populations in fragmented landscapes, the results show that lower habitat quality may be compensated by higher connectivity between host plant patches. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

17.
Remains of a large-bodied species of endemic nesomyid rodent, Macrotarsomys petteri Goodman and Soarimalala, 2005, were identified from subfossil deposits recovered from Andrahomana Cave in extreme southeastern Madagascar. This recently described extant species was previously only known from a single specimen collected at a site about 450 km northwest of Andrahomana and with distinctly different forest habitat than currently found in the vicinity of the cave. Radiocarbon dating of remains of M. petteri from the cave site indicates that it persisted in the region subsequent to human settlement. Previous reports of a large member of Macrotarsomys from other Quaternary sites in southern Madagascar are almost certainly of M. petteri. It is proposed that this species once had a broad distribution across the southern portion of the island during a more mesic period and subsequent aridification of the region has led to its local extirpation across most of its former range. To cite this article: S.M. Goodman et al., C. R. Palevol 5 (2006).  相似文献   

18.
There was a significant inshore to offshore pattern in grouper species composition and density on Florida Keys coral reefs. Red grouper Epinephelus morio and black grouper Mycteroperca bonaci were most abundant on inshore patch reefs. Graysby Cephalopholis cruentata was most abundant on offshore reef types. Density among sites ranged from 0 to 0·43, 0 to 0·26 and 0 to 1·23 100 m−2 for red grouper, black grouper, and graysby, respectively. Grouper density exhibited no consistency among sites within similar reef types. The densities of red and black grouper were correlated significantly with either physical or biotic habitat parameters. Graysby were observed in microhabitats with whose benthic features differed significantly from the surrounding habitat. This species was observed in high-relief areas with significantly less octocoral species and colony densities. Larger graysby were observed in areas of higher relief and less octocorals than smaller graysby. Habitat was one of several important factors influencing the distribution of groupers among coral reefs types in the Florida Keys.  相似文献   

19.
The white-fronted spider monkey, Ateles marginatus, is endemic to Brazilian Amazon between the Tapajós and Xingu Rivers, and is classified as endangered due primarily to habitat loss. This study presents data on the distribution and relative abundance of the species in the northwestern corner of its distribution, on the lower Tapajós River, centered on the 545,000 ha Tapajós National Forest (Flona Tapajós). Quantitative data were collected in line transect surveys at 14 sites, and confirmatory interviews were conducted at these, and a further four sites. The results indicate that A. marginatus is extinct or extremely rare at sites in the northern extreme of the study area, but is relatively widespread further south, except in very small fragments (<100 ha). While the present-day occurrence of A. marginatus is clearly affected by habitat fragmentation, the species’ original distribution appears to have been characterized by local lacunas, determined by factors relating to habitat quality. While hunting pressure does not seem to be a major threat at the present time, competition with a second atelid, Alouatta discolor, may have reinforced the effects of habitat disturbance in some areas, especially smaller fragments. Grouping patterns were typical of the genus, including an apparent female bias in the sex ratio of adults. Overall, the results indicate an ongoing decline in the occurrence of A. marginatus within the study area, local extinction, especially in smaller fragments, and an urgent need for the establishment of effective conservation measures.  相似文献   

20.
During reorganisation of the palaeontology collections at the Department of Antiquities and Museums, Kampala by the Uganda Palaeontology Expedition, several primate postcranial remains from Napak, an Early Miocene site, were found. Several large limb bones are attributed to Proconsul major, already known, already known from the locality on the basis of dental and gnathic remains, but hitherto poorly known postcranially. One specimen belongs to a smaller species of hominoid not represented at Napak by teeth and jaws. Both hominoids show quadrupedal and climbing adaptations, but they differ from each other. Thus Proconsul major praticed ‘power’ climbing whereas the smaller hominoid would have been more ‘agile’. In both cases, the hominoids moved frequently between the trees and the ground, and both were well adapted to their palaeoenvironment, which was dry forest. A further important result of this study is that the postcranial remains of r indicat indicate that it was heavier than had previously been envisaged on the basis of its dental remains. It would have weighed about the same as female gorillas, between 75 and 90 kg. The small species weighed about 20 kg.

Resumé

Lors d'un réaménagement des anciennes collections paléontologiques de l'Uganda Museum, des restes postcrâniens de primate provenant du site Miocène inférieur de Napak ont été retrouvés. Certaines pièces de grandes dimensions sont attribuées à Proconsul major, déjà signalé sur le site à partir de restes dentaires et gnathiques, mais dont l'anatomie postcrânienne était mal connue. D'autres spécimens sont rapportés à un Hominoidea de plus petite taille et non représenté par des dents ou des mâchoires. Les deux hominoïdes montrent des caractéristiques de quadrupèdes pratiquant le grimper mais de façons différentes. Alors que r pratique un gr pratique un grimper puissant, l'Hominoidea de petite taille pratique un grimper plus agile. Quoi qu'il en soit, ces deux espèces se déplaçaient souvent et activement au sol et dans les arbres. Ils vivaient dans une forêt sèche. Cette étude confirme que r, Hominoidea de, Hominoidea de grande taille, avait une masse corporelle plus importante que celle envisagée auparavant à partir des mesures dentaires. Il devait avoir une masse équivalente à celle d'un gorille femelle et peser entre 75 et 90 kg. L'espèce plus petite, quant à elle, aurait pesé 20 à 25 kg environ.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号