Physical control of plankton population abundance and dynamics in intertidal rock pools

Little is known about the population structure and dynamics of plankton of intertidal rock pools. A numerical model was developed for rock pool plankton with growth limited by both tidal washout and the stress associated with adverse conditions in high-shore pools. This model predicts that a stress tolerant species will tend to have maximum population densities in high-shore pools and that populations will fluctuate in opposite phase to the spring-neap tidal cycle. Conversely, where a species is susceptible to stress in high-shore pools, the maximum population density is likely to occur lower on the shore, and numbers in upper shore pools will cycle in phase with the spring-neap cycle. These two alternative predictions were sufficient to classify the dynamics of the most abundant species in time series taken from rock pools in the Isle of Man. The dinoflagellate Oxyrrhis marina followed the predictions of the stress tolerant model. In comparison, the spatiotemporal patterns of other taxa, including a ciliate, a dinoflagellate and cryptophytes, suggested stress-susceptible life histories.     

Inter- and intraspecific morphometric variability in Juniperus L. seeds (Cupressaceae)

In this study, a statistical classifier for Mediterranean taxa of Juniperus, based on 98 seed morphometric parameters, was tested at interspecific, specific and intraspecific levels. Ripe cones of 10 taxa were collected in different regions of the Mediterranean Basin to compare and discuss their taxonomic treatments according to two different sources. High percentages of correct identification were reached for both taxonomic treatments at the specific and intraspecific level and from the comparison among taxa of the J. oxycedrus, J. communis and J. phoenicea complexes. Moreover, ripe cones of J. macrocarpa were collected from four Sardinian populations, in two seasons, and from plant and soil, in order to analyse inter-population, seasonal and source variability in seed morphology. This statistical classifier discriminated J. macrocarpa seeds collected in spring more accurately than those collected in autumn, but it failed to distinguish between the seeds collected from plants and soil, or between those collected from different populations of the same geographic region.     

Population genetic structure of Bombus terrestris in Europe: Isolation and genetic differentiation of Irish and British populations

The genetic structure of the earth bumblebee (Bombus terrestris L.) was examined across 22 wild populations and two commercially reared populations using eight microsatellite loci and two mitochondrial genes. Our study included wild bumblebee samples from six populations in Ireland, one from the Isle of Man, four from Britain and 11 from mainland Europe. A further sample was acquired from New Zealand. Observed levels of genetic variability and heterozygosity were low in Ireland and the Isle of Man, but relatively high in continental Europe and among commercial populations. Estimates of F_st revealed significant genetic differentiation among populations. Bayesian cluster analysis indicated that Irish populations were highly differentiated from British and continental populations, the latter two showing higher levels of admixture. The data suggest that the Irish Sea and prevailing south westerly winds act as a considerable geographical barrier to gene flow between populations in Ireland and Britain; however, some immigration from the Isle of Man to Ireland was detected. The results are discussed in the context of the recent commercialization of bumblebees for the European horticultural industry.     

Descriptions of Protospathidium serpens (Kahl, 1930) and P. fraterculum n. sp. (Ciliophora, Haptoria), two species based on different resting cyst morphology

Protospathidium serpens (Kahl, 1930) is frequent in semiterrestrial and terrestrial habitats worldwide. Conventionally, all populations are considered as conspecific because they have very similar overall morphologies and morphometrics. We studied in detail not only the morphology of the vegetative cells but also the resting cysts using live observation, protargol impregnation, and scanning electron microscopy. These revealed a cryptic diversity and biogeographic pattern in details of the dorsal brush and cyst wall morphology. The cyst wall is spiny in the Austrian specimens, while smooth in the South African and Antarctic populations. Accordingly, P. serpens consists of at least two species: P. serpens (with spiny cyst wall) and P. fraterculum n. sp. (with smooth cyst wall); the latter is probably composed of two distinct taxa differing by the absence (South African)/presence (Antarctic) of a monokinetidal bristle tail in brush row 3, the number of dikinetids comprising brush row 1 (seven versus three), and the total number of brush dikinetids (29 versus 17). Protospathidium serpens is neotypified with the new population from Austria. The significance of resting cyst morphology is discussed with respect to alpha-taxonomy and overall ciliate diversity.     

Kreuzungsexperimente anLaminaria saccharina von Helgoland und von der Isle of Man

The brown algaLaminaria saccharina growing at Helgoland (North Sea) has smooth blades, whereas the blades of the same species occurring at the Isle of Man are covered with deep bullations. Gametophytes of both morphological types were grown in the laboratory and the resulting sporophytes of each type as well as hybrids were planted out in the sublittoral zone of Helgoland for four months. The Isle of Man type and the hybrids both formed bullations. The Isle of Man type differed further from the Helgoland type in that it had broader blades and did not tolerate the water temperatures above 14° C which prevail near Helgoland in summer. All experimental plants were removed from the sea before the blades became sporogenous.     

Chloroplast DNA variation in dactylis glomerata L. taxa endemic to the macaronesian islands

In the Dactylis glomerata infraspecific polyploid grass complex, restriction fragment length polymorphisms (RFLPs) of chloroplast DNA (cpDNA) were studied in diploid and tetraploid populations of several taxa endemic to Macaronesia (Madeira and the Canary islands) and in populations from the African and European continental areas closest to Macaronesia. Two chlorotypes, which differed by a single 290-bp length mutation, were observed in the Macaronesian and the continental populations. Chlorotype I, which is predominant in the whole D. glomerata complex, was found in the majority of continental populations. It was also observed in the most western Macaronesian islands, in the two diploid taxa endemic to the lowland scrub and the high elevation heath of Tenerife, respectively, and in tetraploids endemic to Madeira and La Palma. These island populations were growing under the influence of humid trade winds. Chlorotype II was found in the eastern part of the Archipelago (closer to Africa), which experienced subarid Mediterranean climate conditions, and in very few diploid and tetraploid Mediterranean populations growing at high elevation on the continent. This geographical and climatic distribution of chlorotype variation in Macaronesia is consistent with that reported previously for morphological, allozyme and phenolic variation in the same plant material. Chlorotype II was, however, also observed in tetraploid populations from La Gomera island and in one of the seven tetraploid populations analysed from Madeira, which all showed clearly subtropical characters for morphology, allozymes and phenolic compounds. This result suggests that cpDNA introgression has occurred more than once from the Mediterranean material into the subtropical one and may indicate that colonization between the mainland and islands, or among the islands, probably played a major role in the geographical pattern observed for that marker.     

Precise time interactions between behavioural and morphological defences

Defences induced against predators fall into three basic categories – behavioural, morphological and life history. Many species induce changes in more than one category. A theoretical advantage of a behavioural change is its potential for rapid induction compared to morphology or life history. We tested this theory by comparing modifications in behaviour and morphology along a time line in the hypotrich ciliate Euplotes octocarinatus exposed to chemical cues from Stenostomum virginianum, a predatory flatworm. Behavioural defences were induced much more rapidly than morphological, although as morphological defences became expressed changes in behaviour were slightly relaxed. This suggests a temporal compensatory relationship between the two traits. Behavioural defences are quickly induced to rapidly reduce predation risk, however they are relaxed as morphology changes are realised to avoid paying the cost of expressing both types of defence.     

Mixed patterns of morphological adaptation to insularity in an aerial displaying bird,the Common Snipe Gallinago gallinago

On islands, colonizing birds may evolve behavioural and morphological adaptations to the new environment, often resulting in changes in body size and reduction or even total loss of flight. These island populations have therefore been used to test hypotheses related to adaptations for flight. However, in certain species in which flight is used not only in foraging and migration but also in mating displays, disentangling the effects of natural and social selection is difficult. Thus, sedentary populations of species that perform aerial displays (such as the Common Snipe Gallinago gallinago that breed in the Azores archipelago) may offer an opportunity to separate the effects of natural and social selection on morphology. If insular Common Snipe respond to the characteristic ecological context of oceanic islands, we expect them to differ from migratory conspecifics in body size and by having relatively smaller and more rounded wings. On the other hand, if social selection exerts a more powerful force over the morphology of this species, we expect that sedentary and migratory birds will not differ in flight‐related characters. We tested these hypotheses by comparing morphological characters measured on live Common Snipe captured in the Azores during the breeding season with those measured on migratory specimens hunted during autumn/winter in mainland Portugal. Sedentary Azorean birds were smaller and had relatively shorter tails but did not show the tendency for insular birds to possess more rounded wings as described in other taxa, including in the Azores. Bergman's rule might explain the difference in body size and shorter tails may be responsible for behavioural differences between populations. The lack of difference in wing shape might be explained by the need of the Common Snipe to perform aerial displays during courtship, suggesting an effect of social selection on the migratory strategy of this species.     

Endemic and Indo-Pacific plankton in the Mediterranean Sea: a study based on dinoflagellate records

Aim To investigate biogeographical patterns based on published dinoflagellate records from the Mediterranean and Black Seas, and to provide a tentative list of endemic and Indo‐Pacific dinoflagellates in the Mediterranean Sea. Location Mediterranean Sea, Black Sea. Methods Checklists of dinoflagellates of the Mediterranean and Black Seas were compared with worldwide literature records. Only species reported in the Indo‐Pacific Ocean or exclusively known in the Mediterranean Sea were selected for biogeographical analysis. Results Dinoflagellates in the Mediterranean Sea comprised c. 43% of the world marine species and c. 88% of the dinoflagellate genera. Species richness among the Mediterranean sub‐basins showed marked differences due to the less reliable records of unarmoured (athecate) and rare dinoflagellates. These differences disappeared when only the more easily identifiable taxa were considered. Of the 673 dinoflagellates cited in the Mediterranean, 87% were also reported in the Atlantic Ocean. Only 40 taxa (6% of the total) were considered to be potential Indo‐Pacific species. Most were reported from the Ligurian Sea (21), and only two species from the Levantine basin. The other 48 taxa (7% of total) were known exclusively from the Mediterranean Sea, mainly from the Ligurian Sea. Half of these taxa were reported by a single author. Main conclusions Substantial dinoflagellates species richness can be attributed, in part, to the historical tradition of taxonomic studies in the Mediterranean Sea. The list of species of both Indo‐Pacific and exclusively Mediterranean species included taxa of dubious taxonomic validity or that were insufficiently known. The exclusion of these questionable taxa revealed the near absence of endemic dinoflagellates in the Mediterranean Sea compared with macroscopic organisms. This could be related to: (1) continuous replenishment of the plankton populations by the inflow of Atlantic water through the Strait of Gibraltar, (2) the possibility that species introduced during the Pliocenic flooding after the Messinian salinity crisis have not had enough time to diverge from their Atlantic ancestors, and/or (3) the reliance on traditional taxonomy based on morphological characters, which precludes the detection of cryptic speciation.     

Morphologic and genetic variability in the marine planktonic ciliate Laboea strobila Lohmann, 1908 (Ciliophora, Oligotrichia), with notes on its ontogenesis

Laboea strobila Lohmann, 1908 is a conspicuous oligotrich ciliate in the marine plankton. In order to compare different populations, the morphology of specimens from the Mediterranean Sea, North Sea, and Irish Sea was investigated using live observation, protargol impregnation, and scanning electron microscopy. Furthermore, the PCR-amplified products of the SSrRNA gene from a monoclonal culture of L. strobila from the Mediterranean Sea were sequenced and aligned with sequences of other oligotrichs, including a population of L. strobila from the Atlantic coast of the USA. Finally, the data from the ecological literature were summarized and the cultivation methods were described. The SSrRNA gene sequences of the two distantly located L. strobila populations from the North Atlantic are identical. Likewise, the morphometrics of most populations so far investigated after protargol impregnation (i.e. from the North Atlantic) do not show obvious differences. In all computed phylogenetic trees, L. strobila groups with Strombidium species, forming a monophyletic taxon corresponding to the subclass Oligotrichia. These results are corroborated by the ontogenetic comparison. Since no type species was fixed for Laboea Lohmann, 1908, L. strobila was designated in the present paper.     

Two new species of Phyllonema (Rivulariaceae,Cyanobacteria) with an emendation of the genus

Two untapered, heterocytous species were observed and collected from the intertidal and supratidal zones of the Mexican coastline of the Pacific Ocean near Oaxaca and from the Gulf of Mexico. These populations were highly similar in morphology to the freshwater taxon Petalonema incrustans in the Scytonemataceae. However, 16S rRNA sequence data and phylogenetic analysis indicated that they were sister taxa to the epiphyllic, Brazilian species Phyllonema aveceniicola in the Rivulariaceae, described from culture material. While genetic identity between the two new species was high, they differed significantly in morphology, 16S rRNA gene sequence identity, and sequence and structure of the 16S–23S ITS region. Their morphology differed markedly from the generitype of the previously monotypic Phyllonema, which has tapered, heteropolar, single‐false branched trichomes with very thin or absent sheath. The two new species, Phyllonema ansata and Phyllonema tangolundensis, described from both culture and environmental material, have untapered, isopolar, geminately false branched trichomes with thick, lamellated sheaths, differences so significant that the species would not be placed in Phyllonema without molecular corroboration. The morphological differences are so significant that a formal emendation of the genus is required. These taxa provide a challenge to algal taxonomy because the morphological differences are such that one would logically conclude that they represent different genera, but the phylogenetic evidence for including them all in the same genus is conclusive. This conclusion is counter to the current trend in algal taxonomy in which taxa with minor morphological differences have been repeatedly placed in separate genera based primarily upon DNA sequence evidence.     

Status of the Hen Harrier Circus cyaneus in the UK and Isle of Man in 2004, and a comparison with the 1988/89 and 1998 surveys

Capsule The population of breeding Hen Harriers in the UK and Isle of Man increased between 1998 and 2004, although country and regional trends differed.

Aims To estimate the size of the UK and Isle of Man Hen Harrier breeding population in 2004, and to compare this with previous estimates made in 1988/89 and 1998.

Methods Surveys were carried out in core and a stratified random sample of 10-km squares throughout the known range, using the same methods as in the 1988/89 and 1998 national surveys.

Results There were an estimated 806 territorial pairs in the UK and Isle of Man in 2004, a significant 41% increase from the 1998 estimate of 570 pairs. Increases were found throughout, with the exception of south and east Scotland and England, where numbers decreased. Scotland held 79% of the UK and Isle of Man breeding population in 2004, and 10% of Scottish pairs were associated with non-moorland habitats, such as mature conifer plantations and scrub/brash.

Conclusions There was a substantial increase in the breeding population in most regions of the UK and Isle of Man between 1998 and 2004, possibly aided by increased use of non-moorland habitats. However, populations declined in upland areas of southern and eastern Scotland and northern England. Continuing illegal persecution arising from perceived conflicts between breeding Hen Harriers and driven grouse shooting may be a major cause of these regional declines.     

Rumen Microbial Ecology in Mule Deer

Mule deer rumen microbial populations from animals in the natural habitat in Utah and from captive deer fed various rations were studied. The microorganisms were characterized on the basis of morphology and Gram reaction. Rumen samples contained 13 identifiable types of bacteria and one genus of ciliate protozoa (Entodinium). Highest rumen bacterial populations were produced on rations containing barley. No differences in proportions of ruminal bacteria in the various morphological groups could be detected when animals were fed either natural browse plants or alfalfa hay. The total numbers of bacteria were similar for animals feeding on controlled diets of browse or hay and those in the natural habitat. Numbers of some bacterial types were directly related to ciliate protozoal numbers, whereas others were inversely related. Highest rumen ciliate protozoal populations were observed on rations containing barley. No differences in protozoal populations were noted between diets containing only browse or hay. Seasonal variations were noted in ciliate protozoal numbers from deer feeding in the natural habitat. The total number of ciliate protozoa decreased in the fall and winter and remained low until spring. There were indications that salt in the deer diet favorably affected rumen ciliate protozoa. Rather than revealing direct deer management applications, this study serves to stimulate and illuminate new approaches to research in range and wildlife nutrition.     

Phylogeography and historical demography of the Lusitanian snail <Emphasis Type="Italic">Elona quimperiana</Emphasis> reveal survival in unexpected separate glacial refugia

Background  

Present day distributions of Palearctic taxa in northern latitudes mainly result from populations having survived in local patches during the Late Pleistocene and/or from recolonizing populations from southern temperate refugia. If well-studied Mediterranean and eastern European refugia are widely accepted, some recent biogeographical assumptions still remain unclear, such as the occurrence of multiple glacial refugia in Iberia and cryptic refugia in northern Europe during the last glaciations. The Lusitanian snail Elona quimperiana has a remarkably disjunct distribution, limited to northwestern France (Brittany), northwestern Spain and the Basque Country. By describing the phylogeographical structure of this species across its entire range, the present study attempts to identify refugia and subsequent recolonization routes.     

Replacement of a native freshwater macroinvertebrate species by an invader: implications for biological water quality monitoring

The rate of freshwater invasions may be increasing, and macroinvertebrate invaders can have significant impacts on native macroinvertebrate assemblage structure through biotic interactions. More pollution-tolerant invaders can often replace native species. We examined implications of a species replacement for accurate biological monitoring of river systems using biotic indices. Our study uses Northern Ireland and the Isle of Man as examples of countries that possess river networks with many riverine macroinvertebrate assemblages subject to invasion. The introduced amphipod crustacean Gammarus pulex has replaced the native species G. duebeni celticus in many rivers in N. Ireland and the Isle of Man. Extensive seasonal data sets (119 sites) from three river networks, Lough Neagh and the Lagan in N. Ireland, and island-wide in the Isle of Man, were used to investigate the assumed equivalence of the native and invader in biotic indices concerned with the water quality monitoring system. Based on the derivation of the Biological Monitoring Working Party (BMWP) score, the Average Score Per Taxon (ASPT), as an example of a commonly used biotic index of water quality, we found index scores were lower in G. pulex sites compared to G. d. celticus-only sites. This indicated that assemblages were dominated by taxa more tolerant of organic pollution in the invader sites and more sensitive in the native sites. Inclusion of the invader in generation of the ASPT index, overinflated the ASPT values obtained compared to those with the native’s inclusion. This questions the accuracy of the ASPT and similar indices in rivers where the invader had replaced the native. We argue that with invasion pressures increasing, the validity of water quality indices such as the BMWP/ASPT needs to be re-examined in catchments where invaders have replaced natives. Indices such as the BMWP/ASPT are based on family level taxa and are inevitably coarse in their resolution given the wide range of water qualities tolerated by different genera within families. We argue that this resolution is even more compromised by the presence of very pollution-tolerant invaders, who may have replaced natives in disturbed or degraded river systems. The whole structure of water quality indices such as the BMWP/ASPT may need revising to take into account the presence of invasive species within monitored assemblages.     

A study of Sarcocornia A.J. Scott (Chenopodiaceae) from Western Mediterranean Europe

The latest publications on Sarcocornia taxonomy and phylogeny recognize six taxa in this genus on the Iberian Peninsula: S. perennis, S. fruticosa, S. alpini, S. alpini subsp. carinata, S. hispanica, and S. pruinosa. The present study represents a comprehensive revision of the different taxa in the Sarcocornia genus present in Western Mediterranean Europe by means of morphological, micromorphological and phylogenetic internal transcribed spacer (ITS) analysis. Morphological and micromorphological data were studied from Sarcocornia samples from 113 populations in coastal salt marshes and inland salt pans in Portugal, France, Spain and Italy. Sixteen new ITS sequences were obtained from Mediterranean Sarcocornia species and analysed together with previous reported data. Published karyological, ecological and biogeographical data from Western Mediterranean Europe were also reviewed. The results indicate the presence of a new species, S. lagascae, found growing in coastal Mediterranean areas of the Iberian Peninsula. The species S. fruticosa was found to be absent from the Iberian territories.     

土壤腹毛类纤毛虫四新纪录种

利用非淹没培养皿法、活体观察和蛋白银染色法,研究了青岛的土壤纤毛虫,发现2属4种我国新纪录种:澳洲管膜虫(Cyrtohymena australis Foissner,1995)、四核管膜虫[C.quadrinucleata(DragescoNjine,1971)]、犬牙管膜虫[C.candens(Kahl,1932)]及迟钝澳纤虫(Australocirrus oscitans BlattererFoissner,1988)。文中对该4种纤毛虫的活体形态和纤毛图式进行了观察记述,补充了前人描述的不足,并依据统计学特征与相近种群进行了比较。     

MEDITERRANEAN CAULERPA TAXIFOLIA AND C. MEXICANA (CHLOROPHYTA) ARE NOT CONSPECIFIC

In 1984, Caulerpa taxifolia (Vahl) C. Agardh was reported along the coast of Monaco. Over the past decade it has spread along 60 km of the Mediterranean coastline and presently represents a potential risk to biodiversity. Several explanations have been advanced regarding the presence of C. taxifolia in the Mediterranean. One hypothesis maintains that the alga was introduced accidentally into the sea at Monaco, where it has been used as a decorative alga in aquaria. Caulerpa taxifolia has not been reported in earlier marine floras of the Mediterranean, and its sudden appearance has suggested that it may be a recent introduction. Another hypothesis proposes that C. taxifolia and Caulerpa mexicana Sonder ex Kützing are morphological variants of one another and hence conspecific taxa. Caulerpa mexicana has been found in the eastern Mediterranean since at least 1941. In order to establish the taxonomic identities of these taxa, individuals from five populations of C. taxifolia and four populations of C. mexicana were collected from within and outside of the Mediterranean. Comparative DNA sequence analysis of the nuclear ribosomal cistron, including the 3′-end of the 18S, ITS1, 5.8S, and ITS2 regions, show clear phylogenetic separation of the two taxa using parsimony and maximum likelihood analyses. Separation is maintained whether the analyses are based on just the more conserved 18S data or just the fast- evolving spacers. The two species are thus not conspecific. For specimens of uncertain identity (i.e. taxifolia–mexicana intermediates), a PCR diagnostic amplification can easily be performed because the ITS1 in C. taxifolia is 36 nucleotides shorter than the ITS1 in C. mexicana. Whether or not C. taxifolia has been present for a longer period of time in the marine flora, either as a cryptic endemic species or as the result of one or more introductions, represents an additional hypothesis that will require identification of biogeographic populations from throughout the world, as well as a population-level study of the Mediterranean region.     

寡毛类纤毛虫变游虫新属的建立及基尔变游虫(新属,新组合)的形态学重描述与系统地位分析(英文)

利用蛋白银染色技术对采自青岛沿海砂隙的寡毛类纤毛虫Strombidium kielum进行了形态学重描述,发现该种在寡毛类纤毛虫中具有独一无二的纤毛下器模式,因此为其建立了1新属Varistrombidium,特征为具有5条斜穿虫体的体动基列,其中体动基列1和2延伸到虫体背部,终止于虫体尾端。对Varistrombidium kielum(Maeda&Carey,1985)nov.comb.的小亚基RNA序列分析表明,该种位于Strombidiidae科内,与其形态学相近种Omegastrombidium elegans聚在一起。同时对其小亚基RNA序列可变区2的二级结构进行了预测并与其形态学相似种进行了比较。还对Apostrombidium pseudokielum Xuet al.,2009进行了补充性描述。     

Sexual reproduction in British Ectocarpus Siliculosus (Phaeophyta)

One male and one female gametophyte of Ectocarpus siliculosus have been detected in a sample of 19 plants taken from the Isle of Man. Fertilization takes place between gametes formed in plurilocular gametangia. Clear cross-fertility exists with Mediterranean strains. This result confirms the notion that the concept of the gametic character of meiospores in Ectocarpus should be abandoned.