Latitudinal gradients in Atlantic reef fish communities: trophic structure and spatial use patterns

Trophic strategies and spatial use habits were investigated in reef fish communities. The results supported the hypothesis of differential use of food resources among tropical and higher latitude reef fishes, i.e . the number of species and relative abundance of fishes relying on relatively low‐quality food significantly decreased from tropical to temperate latitudes. The species : genus ratio of low‐quality food consumers increased toward the tropics, and was higher than the overall ratio considering all fishes in the assemblages. This supports the view that higher speciation rates occurred among this guild of fishes in warm waters. It was also demonstrated that density of herbivorous fishes (the dominant group relying on low‐quality food resources) in the western Atlantic decreased from tropical to temperate latitudes. Spatial use and mobility varied with latitude and consequently reef type and complexity. Fishes with small‐size home ranges predominated on tropical coral reefs.     

The phytogeography ofCladophora (Chlorophyceae) in the northern Atlantic Ocean,in comparison to that of other benthic algal species

About 43Cladophora species inhabit the coasts of the northern Atlantic Ocean. These can be subdivided into seven distribution groups: (a) the tropical western Atlantic group (16 species); (b) the warm temperate Mediterranean-Atlantic group (9 species); (c) the warm temperate North American group (1 species); (d) the Arctic group (1 species); (e) the amphiatlantic tropical to warm temperature group (7 species); (f) the amphiatlantic tropical to temperate group (4 species), and (g) the amphiatlantic temperate group (5 species). These groups agree with general phytogeographic patterns. Thus, the high numbers of species restricted to the tropical western Atlantic region and the warm temperate Mediteranean-Atlantic region are in agreement with the richness and high degree of endemism of these regions. The fact that all species occurring in northeast America also occur in Europe agrees with the high floristic similarity of the boreal areas in America and Europe. The sediment coasts of the Carolinas are an efficient barrier to the south-north dispersal of benthic algae. The temperature bound phytogeographic limits are set in most cases by the species ability to survive adverse temperatures; for “northern” species to survive a high summer temperature in the south, and for “southern” species to survive a low winter temperature in the north. The limits in the Arctic region are all set by the species ability for sufficient growth and reproduction in summer. Conversely, only few northern species have a southern limit which is set by a winter temperature that is not too high for sufficient growth and reproduction. Most species of this group are winter-annuals at their southern limit, and summer-annuals at their northern limit. A comparatively small number of species with a tropical-to-warm temperate distribution have a northern limit at temperate latitudes which is set by a sufficiently high summer temperature for growth and reproduction. A high proportion of this group are lagoonal or quiet water species, which profit by higher summer temperatures in sheltered waters.C. vagabunda is an example.C. rupestris andC. sericea have an amphiboreal distribution and also occur in the southern temperate belt. They probably used a Pleistocene temperature drop to disperse, through the Atlantic along the African coast, from one hemisphere to the other. In the Pacific temperatures were not sufficiently low for this dispersal; and hence these two species reached the Pacific probably by way of the Bering Strait.     

The effect of latitudinal gradient on the species diversity of Chinese litter-dwelling thrips

To understand the global distribution patterns of litter-dwelling thrips, a total 150 leaf litter samples were collected from 6 natural reserves located in three climatic regions, temperate, subtropical and tropical. The results showed the relative abundance of Thysanoptera was over 3.0% in 4 natural reserves from subtropical and tropical zone, and reached 5.9% in one tropical reserve, only less than Acarina and Collembola. In contrast it was only 0.3% in the warm temperate natural reserves, and no thrips were collected in a mid temperate reserve. The order on the average species numbers per plot of litter thrips was tropic > subtropics > temperate (n=25, p<0.05). Mean density of litter thrips per plots in the tropics and subtropics was significantly higher than that in the temperate region (n=25, p<0.05), but the average density was not significantly different between tropical and subtropical zones (n=25, p>0.05). The diversity of litter thrips in the tropics and subtropics was much higher than that in the temperate area based on comparsions of Shannon-Wiener diversity index (H’), Pielou eveness index (J), and Simpson dominance index (D). All of these results indicated that litter-dwelling thrips lived mainly in tropical and subtropical regions; meanwhile, species number and relative abundance increased with decreasing latitude.     

Relationships between environmental gradients and geographic variation in the intraspecific body size of three species of frogs (Anura)

The relationship between environmental gradients and patterns of geographic variation in body size has been a controversial topic for ectothermic organisms globally. To examine whether the patterns that generally hold in more temperate species also hold for tropical ones, we examined the intraspecific body size variation in three species of Neotropical frogs, Dendropsophus minutus, Hypsiboas faber and Physalaemus cuvieri, along different environmental gradients (e.g. temperature, precipitation and topography). We analysed four competing hypotheses: (i) the water availability hypothesis that predicts a negative relationship between body size and precipitation; (ii) the heat balance hypothesis that predicts a negative relationship between body size and temperature; (iii) the topography hypothesis that predicts a negative relationship between body size and altitude; and (iv) the mixed‐effect hypothesis that predicts that individuals occurring in wet and cold sites would be larger than individuals occurring in dry and warm sites. The spatial pattern of geographic variation in body size among populations of H. faber was associated with the mixed‐effect hypothesis. In localities with low precipitation seasonality and cold conditions, H. faber individuals were larger than in localities with high precipitation seasonality and warm conditions. Variation in the body size of D. minutus was the opposite of that predicted by the heat balance hypothesis. Individuals in localities with high temperatures were larger than in localities with low temperatures. On the other hand, variation in the body size of P. cuvieri was not associated with the variables used in this study. Our results suggest that intraspecific variation in anuran body size is more dependent on species‐specific response than on the region (i.e. temperate or tropical) where they occur.     

World-wide latitudinal and longitudinal seaweed distribution patterns and their possible causes,as illustrated by the distribution of Rhodophytan genera

The degree of similarity between red algal generic floras in each pair of 22 climatically defined biogeographic regions was established on a world-wide scale by Jaccard's similarity index and by an hierarchical clustering with an agglomerative centroid method. Two clusterings were carried out, the first one on the basis of all 637 genera, and the second one on the basis of genera not occurring in the tropics and non-endemic to any one of the 22 regioms (145 genera). This latter clustering served to detect better the relationships among non-tropical floras. The results indicate the following division of the earth's rhodophytan seaweed floras: (1) A rich tropical-warm temperate "Tethyan" group including the rich tropical Indo W Pacific and W Atlantic floras, and the rich warm temperate NW Pacific and NE Atlantic floras; (2) the depauperate extensions of the above group (the tropical E Pacific and E Atlantic floras, and the warm temperate NW and SW Atlantic floras); (3) a cold temperate and a warm temperate N Pacific group; (4) an Arctic-cold temperate N Atlantic group and a NE Atlantic warm temperate flora; (5) an Antarctic-cold temperate southern hemisphere group including the cold temperate SE Pacific, SW Atlantic, SE Atlantic floras, and the Antarctic flora; (6) the two highly individual, but slightly related warm temperate SE Atlantic flora (S. Africa) and SW Pacific flora (Southern Australia and Northern New Zealand); (7) the depauperate warm temperate SE Pacific flora. Although the northern and southern hemisphere temperate and polar floras are quite unrelated (on the basis of genera lacking in the tropics), they share nonetheless a number of cool water genera which apparently have succeeded in passing the adverse tropical belt. The rich tropical-warm temperate group is thought to consist of vicariant portions of a formerly continuous Tethyan flora. The N Pacific and N Atlantic temperate floras are thought to have developed independently since the Oligocene (~ 40.10⁶ y) deterioration of the climate and to have partially mixed their cool water genera only after the Pliocene inundation (2.10⁶ y) of the Bering Land Bridge. The warm-temperate floras of S Africa and southern Australia probably owe their richness and individuality to a very long isolation (already at the start of the Cenozoicum) and a continued residence in warm temperate conditions with small seasonal fluctuations.Paper presented at the Seaweed Biogeography Workshop of the International Working Group on Seaweed Biogeography, held from 3–7 April 1984, at the Department of Marine Biology, University of Groningen (The Netherlands). Convenor: C. van den Hoek.     

Competition, coexistence, and adaptation amongst rodent invaders to Pacific and New Zealand islands

Variation in skull size was investigated for three species of rats (kiore –Rattus exulans Peale; ship rat –R. rattus L.; Norway rat –R. norvegicus Berkenhout) which were introduced by humans to various islands in New Zealand and other Pacific islands. Data from seventy-one islands and 882 specimens are examined for evidence of the effects of latitude, island size and interspecific competition among rats and the house mouse (Mus musculus L.) on skull size, using multiple regressions. For R. exulans, skull size increases with latitude as predicted by Bergmann's rule, but no such effect occurs for the other two rats. There was a positive relationship between island size and the number of species inhabiting it, and some species combinations were more likely to occur than others. For example, R. exulans and R. norvegicus were more likely to occur together, while R. rattus and R. exulans were rarely sympatric. R. exulans and R. rattus skull size was negatively correlated with the number of other rodents on the same island. R. exulans skull size increased on smaller islands in some island groups, perhaps because increased density and consequent increased intraspecific competition on smaller islands favours increased body size. This effect is more pronounced in tropical islands (Solomon islands), than in subtropical ones (Hawaiian islands) and less so in temperate New Zealand. Collectively the data demonstrate that rapid evolution of body size in predictable directions can follow within 150 years of the introduction of species to new receiving communities.     

Novel species interactions and environmental conditions reduce foraging competency at the temperate range edge of a range-extending coral reef fish

Poleward range extensions of coral reef species can reshuffle temperate communities by generating competitive interactions that did not exist previously. However, novel environmental conditions and locally adapted native temperate species may slow tropical invasions by reducing the ability of invaders to access local resources (e.g. food and shelter). We test this hypothesis on wild marine fish in a climate warming hotspot using a field experiment encompassing artificial prey release. We evaluated seven behaviours associated with foraging and aggressive interactions in a common range-extending coral reef fish (Abudefduf vaigiensis) and a co-shoaling temperate fish (Microcanthus strigatus) along a latitudinal temperature gradient (730 km) in SE Australia. We found that the coral reef fish had reduced foraging performance (i.e. slower prey perception, slower prey inspection, decreased prey intake, increased distance to prey) in their novel temperate range than in their subtropical range. Furthermore, higher abundance of temperate fishes was associated with increased retreat behaviour by coral reef fish (i.e. withdrawal from foraging on released prey), independent of latitude. Where their ranges overlapped, temperate fish showed higher foraging and aggression than coral reef fish. Our findings suggest that lower foraging performance of tropical fish at their leading range edge is driven by the combined effect of environmental factors (e.g. lower seawater temperature and/or unfamiliarity with novel conditions in their extended temperate ranges) and biological factors (e.g. increased abundance and larger body sizes of local temperate fishes). Whilst a future increase in ocean warming is expected to alleviate current foraging limitations in coral reef fishes at leading range edges, under current warming native temperate fishes at their trailing edges appear able to slow the range extension of coral reef fishes into temperate ecosystems by limiting their access to resources.

     

Sur quelques zooplanctontes abondants dans l'upwelling de Cabo Frio (Bresil)

On some zooplankters common in the Cabo Frio (Brazil) upwelling.In the waters off Cabo Frio zooplankton maxima are observedbetween February and April, which is the period of upwellingoccurrence. Copepods are highly diversified; we identified 96species at a single collecting station during one year. In summerCalanoides carinatus, Paracalanus parvus and Oncea media areabundant, whereas we observed dominance of Temora stylifera,Clausocalanus furcatus, C. arcuicomis, Oithona plumifera andgreat quantity of Creseis acicula during winter. Chaetognatha(Sagitta enflata), Appendicularia (Oikopleura longicauda), Ostracoda(Conchoecia spp.) and Pteropoda (Limacina sp.) are permanentthroughout the year, and maximum in summer. The vertical distributionof zooplankton depends on the hydrological structure, i.e. natureof the water mass and degree of mixing between different waters.Brazil current water, with low quantity of organisms and dominanceof copepods (Clausocalanus furcatus, Mecynocera clausi, Corycaeidae,Oithonidae, Oncaeidae) accompanied by Evadne spinifera and Lucifertypicus. South Atlantic Central Water (upwelling water) characterizedby rare deep copepods and abundance of Calanoides carinatusand Ctenocalanus vanus which are excellent indicator speciesfor upwelling occurrence. Coastal water, with low salinity,where some species with brackish affinity are observed, likeOithona ovalis and Podon polyphemoides.     

Nutritional requirements of sheep,goats and cattle in warm climates: a meta-analysis

The objective of the study was to update energy and protein requirements of growing sheep, goats and cattle in warm areas through a meta-analysis study of 590 publications. Requirements were expressed on metabolic live weight (MLW=LW^0.75) and LW¹ basis. The maintenance requirements for energy were 542.64 and 631.26 kJ ME/kg LW^0.75 for small ruminants and cattle, respectively, and the difference was significant (P<0.01). The corresponding requirement for 1 g gain was 24.3 kJ ME without any significant effect of species. Relative to LW^0.75, there was no difference among genotypes intra-species in terms of ME requirement for maintenance and gain. However, small ruminants of warm and tropical climate appeared to have higher ME requirements for maintenance relative to live weight (LW) compared with temperate climate ones and cattle. Maintenance requirements for protein were estimated via two approaches. For these two methods, the data in which retained nitrogen (RN) was used cover the same range of variability of observations. The regression of digestible CP intake (DCPI, g/kg LW^0.75) against RN (g/kg LW^0.75) indicated that DCP requirements are significantly higher in sheep (3.36 g/kg LW^0.75) than in goats (2.38 g/kg LW^0.75), with cattle intermediate (2.81 g/kg LW^0.75), without any significant difference in the quantity of DCPI/g retained CP (RCP) (40.43). Regressing metabolisable protein (MP) or minimal digestible protein in the intestine (PDI_min) against RCP showed that there was no difference between species and genotypes, neither for the intercept (maintenance=3.51 g/kg LW^0.75 for sheep and goat v. 4.35 for cattle) nor for the slope (growth=0.60 g MP/g RCP). The regression of DCP against ADG showed that DCP requirements did not differ among species or genotypes. These new feeding standards are derived from a wider range of nutritional conditions compared with existing feeding standards as they are based on a larger database. The standards seem to be more appropriate for ruminants in warm and tropical climates around the world.     

Nest attendance by tropical and temperate passerine birds: Same constancy,different strategy

相似文献   

Phytoplankton and its dynamics in two tropical lakes: a tropical and temperate zone comparison

Temporal patterns of phytoplankton biomass and community structure are described for two Kenyan lakes and subsequently compared with patterns reported in other tropical and temperate lakes. Lake Naivasha had a lower and more seasonally variable (10×) biomass, with a seasonal shift between diatoms and blue-greens, while the L. Oloidien biomass was less variable (3.7×) and dominated by blue-greens. Biomass and chlorophyll a were strongly correlated and in turn were coupled to the level of total phosphorus. A total of 143 and 94 taxa were described for L. Naivasha and L. Oloidien, respectively.The comparative analysis showed: a) a paucity of exclusively tropical species; b) that more than 30 percent of the species in two highly saline Kenyan lakes were also present in the two freshwater lakes; c) no evidence for a postulated decline of phytoplankton species abundance with latitude from the temperate zone to the tropics; d) that the low fraction of chrysophyte biomass in tropical lakes is a function of trophy rather than of latitude; e) that the fraction of chlorophyte biomass in tropical lakes is generally higher than in temperate lakes; f) that the proportion of nannoplankton in the two Kenyan freshwater lakes is not different from that in temperate lakes of the same trophy; g) that seasonal or annual biomass oscillations in the tropics are not systematically lower than in the temperate zone; h) evidence for large inter-year difference in the max.:min. biomass ratio in the only tropical lake (L. Naivasha) for which such data are available; i) that an average biomass ratio appears predictable for tropical lakes from the proportion of the sediment surface in contact with epilimnetic water. Overall, no evidence was found that the freshwater tropical phytoplankton composition or dynamics differ in any fundamental fashion from that observed in the temperate lakes during the summer.Contribution number 147 of the Limnology Research Centre, McGill University.     

THE GENUS TRAPANIA (NUDIBRANCHIA: GONIODORIDIDAE) IN THE INDO-WEST PACIFIC

Seven new species of the nudibranch genus Trapania Pruvot-Fol,1931 (Goniodorididae) are described from the Indo-West Pacificand an eighth species, T. japonica (Baba, 1935), originallydescribed from one preserved specimen from Japan, is redescribedfrom specimens collected in Hong Kong and tropical eastern Australia.Three of the new species are from temperate south-eastern Australiaand one from tropical eastern Australia. Two species are knownonly from Hong Kong and a third is recorded from the SudaneseRed Sea as well as Hong Kong. Only ten other species of Trapania have been described, sixof those from Europe, and one each from Brazil, California,Japan and New Zealand. The anatomy and external colour patternof these species is compared with that of the seven new species. (Received 12 December 1986;     

Bergmann and converse bergmann latitudinal clines in arthropods: two ends of a continuum?

Two seemingly opposite evolutionary patterns of clinal variationin body size and associated life history traits exist in nature.According to Bergmann's rule, body size increases with latitude,a temperature effect. According to the converse Bergmann rule,body size decreases with latitude, a season length effect. Athird pattern causally related to the latter is countergradientvariation, whereby populations of a given species compensateseasonal limitations at higher latitudes by evolving fastergrowth and larger body sizes compared to their low latitudeconspecifics. We discuss these patterns and argue that theyare not mutually exclusive because they are driven by differentenvironmental causes and proximate mechanisms; they thereforecan act in conjunction, resulting in any intermediate pattern.Alternatively, Bergmann and converse Bergmann clines can beinterpreted as over- and undercompensating countergradient variation,respectively. We illustrate this with data for the wide-spreadyellow dung fly, Scathophaga stercoraria (Diptera: Scathophagidae),which in Europe shows a Bergmann cline for size and a converseBergmann cline (i.e., countergradient variation) for developmenttime. A literature review of the available evidence on arthropodlatitudinal clines further shows a patterned continuum of responses.Converse Bergmann clines due to end-of-season time limitationsare more common in larger species with longer development times.Our study thus provides a synthesis to the controversy aboutthe importance of Bergmann's rule and the converse Bergmannrule in nature.     

BIOCHEMICAL GENETICS AND SPECIES RELATIONSHIPS WITHIN THE GENUS HALIOTIS (GASTROPODA: HALIOTIDAE)

The marine gastropod genus Haliotis includes 60–70 describedspecies distributed along the coastlines of most continentsand of islands in the Pacific, Indian and Atlantic Oceans. Theyoccur in tropical and temperate regions of both hemispheres.Protein gel electrophoresis revealed genetic relationships amongseventeen temperate species; Haliotis rubra, H. conicopora,H. laevigata, H. roei, H. scalaris, H. cyclobates, H. coccoradiata,H. midae, H. iris, H, austrails, H. virginea, H. discus hannai,H. kamtschaktkana, H. rufescens, H. corrugata, H. cracherodii,and H. fulgens. Northern temperate species clustered together, but northernand southern species shared so few allelic states that theycould not be united on a single genetic distance diagram. Nordid all the southern temperate species form a single cluster.In addition, genetic characters do not support previous sub-genericdivisions within Haliotis. The observed genetic distances betweensome species were found to be large, and in some cases larger,than those normally associated with species in the same genus.These relationships provide insight into the evolutionary historyand biogcography of the group and emphasize the need for taxonomicreview based on both morphological and genetic information. (Received 8 September 1992; accepted 1 February 1993)     

Acclimation of Intertidal Crabs

SVXOPSIS. Intertidal crabs are subjected to marked fluctuationsin environmental factors. Temperature and salinity influencethe distribution of organisms both on a latitudinal basis andalong a subtidal to terrestrial gradient. These factors areoperative on all stages of the life history. Resistance-adaptations. Adult fiddler crabs (genus Uca) fromthe temperate zone are more resistant to low temperature thantropical species. Also, the tolerance to low temperature ofcrabs from the temperate zone is greatly influenced by thermalacclimation, i.e. cold-acclimated crabs are more resistant thanwarm-acclimated animals. In contrast, tropical species havelimited adaptive ability. At elevated temperatures no consistentdifference in the lethal limits of crabs from tropical and temperatezones is observed. In contrast with the adults, larvae of tropicalspecies are cold-resistant. However, the larvae of all speciestested are more sensitive to reduced salinities than are theadults. Capacity-adaptatioyis. Subtidal species of crabs tend to havea lower level of respiratory performance, as measured by variousindices, than crabs from the intertidal zone. The metabolicresponse of fiddler crabs from the temperate zone is more labileat low temperature than in species from the tropical zone. Atelevated temperature the reverse response is observed. On aninterspecific basis, differences in the metabolictemperaturepatterns of acclimation of latitudinally separated populationsof U. pugilator are observed when based on the hypotheticalschemes of Bullock, Precht, and Prosser.     

Systematic variation in the logarithmic ranges in abundance of freshwater phytoplankton populations

相似文献   

Patterns of distribution for southern Australian marine echinoderms and decapods

Aim To relate patterns of distribution of marine echinoderms and decapods around southern Australia to major ecological and historical factors. Location Shallow‐water (0–100 m) marine waters off southern Australia, south of 30° S. Methods (1) Record the presence/absence of known echinoderm and decapod species in cells of c. 1° latitude and longitude, along the coast of southern mainland Australia and Tasmania. (2) Describe patterns in species composition, species richness and endemism through gradient analysis, ordination and cluster analysis. (3) Relate these patterns to distance and temperature gradients, the area of continental shelf, the average size of species range, and known historical factors. Results Species composition varied with both latitude and longitude. Species richness was relatively constant from east to west but graded with latitude from high in the warm‐temperate regions around Perth and Sydney to low in cool‐temperate southern Tasmania. Species richness was not related to the area of continental shelf or average species range size. Species turnover was not correlated with rates of temperature change. It was problematic to separate distance from temperature gradients, but there was evidence that the southern distribution limits of some species are related to minimum sea surface temperature. Within the taxonomic groups surveyed, evolutionary radiation has been largely limited to a few cosmopolitan species‐rich genera. Main conclusions There are historical as well as ecological hypotheses explaining the latitudinal gradient of marine species richness in southern Australia: (1) the continual invasion and speciation of species of tropical origin as Australia has split from Gondwana and drifted northward; (2) progressive extinction of some Gondwanan cool‐temperate species at the limits of their range; (3) low level of immigration of additional cool‐temperate species; and (4) some in situ endemic speciation.     

PHYLOGENY AND BIOGEOGRAPHY OF THE ATLANTIC AND EASTERN PACIFIC HYPSELODORIS STIMPSON, 1855 (NUDIBRANCHIA, CHROMODORIDIDAE) WITH THE DESCRIPTION OF A NEW SPECIES FROM THE CARIBBEAN SEA

A new species, based on two specimens from Guana Island, BritishVirgin Islands, is described. The new species agrees with thegenus Hypselodoris in having a high body profile, a large vestibulargland and mantle glands. It differs from other members of thegenus in the Atlantic Ocean by having a reddish background bodycolour. In addition, dorsal colour patterns such as a broadcentral white line with lateral extensions and the lack of yellowlines or spots further differentiate this species. The radularformula of 52x41.0.41 and a smaller seminal receptacle are alsodistinctive. The phylogenetic relationships of 34 species andsubspecies of Hypselodoris from the eastern Pacific and Atlanticare examined using morphological characters. With the exceptionof the new species, these are characterized by a dark blue backgroundbody colour. The phylogenetic analysis of the data matrix resultedin eight most-parsimonious trees. The resulting consensus treeshows that eastern Pacific and Atlantic species of Hypselodorisconstitute a monophyletic group that is basally split into twosister clades. One clade contains the eastern Pacific speciesand most of the Caribbean species, whereas the other clade containsthe eastern Atlantic species. The new species is the sisterto the rest of the Caribbean species, which also form a monophyleticgroup. This phylogenetic hypothesis suggests that two consecutivevicariant events have affected the biogeography of Hypselodoris:(1) the closure of communication between the tropical Indo-Pacificregion and the Atlantic and eastern Pacific, completed withthe formation of the East Pacific Barrier; and (2) the riseof the Panama isthmus. (Received 19 December 2003; accepted 12 October 2005)     

Causes and consequences of thermal tolerance limits in rocky intertidal porcelain crabs, genus petrolisthes

Vertical zonation of intertidal organisms, from the shallowsubtidal to the supralittoral zones, is a ubiquitous featureof temperate and tropical rocky shores. Organisms that livehigher on the shore experience larger daily and seasonal fluctuationsin microhabitat conditions, due to their greater exposure toterrestrial conditions during emersion. Comparative analysesof the adaptive linkage between physiological tolerance limitsand vertical distribution are the most powerful when the studyspecies are closely related and occur in discrete vertical zonesthroughout the intertidal range. Here, I summarize work on thephysiological tolerance limits of rocky intertidal zone porcelaincrab species of the genus Petrolisthes to emersion-related heatstress. In the eastern Pacific, Petrolisthes species live throughouttemperate and tropical regions, and are found in discrete verticalintertidal zones in each region. Whole organism thermal tolerancelimits of Petrolisthes species, and thermal limits of heartand nerve function reflect microhabitat conditions. Speciesliving higher in the intertidal zone are more eurythermal thanlow-intertidal congeners, tropical species have the highestthermal limits, and the differences in thermal tolerance betweenlow- and high-intertidal species is greatest for temperate crabs.Acclimation of thermal limits of high-intertidal species isrestricted as compared to low-intertidal species. Thus, becausethermal limits of high-intertidal species are near current habitattemperature maxima, global warming could most strongly impactintertidal species.     

中国典型地带陆生等足类的区系研究

通过对我国５个典型地带（热带、亚热带、暖温带、高寒带）２０个样点进行陆生等足类的调查采集，共发现陆生等足类１１科、２９属、７２种。由于各地带自然环境明显不同，造成了物种分布上的差异，其中热睡亚热睦区种类最多，分别为３８种和４７种，两地带物种共占总种数的８０％以上；曙带和温带地区仅发现９种，而高寒带由于平均气温在０℃以下，不利于陆生等足类的生存，故迄今仅发现２种。其区系特点为：（１）区系分布的地带性