Gelidiaceae (Rhodophyta) in Bahía de Banderas,Western Pacific,México

We present the results of a floristic study of intertidal species of Gelidiaceae collected in ten localities in the Bahía de Banderas region. The study area is within an extensive overlapping transitional zone between the tropical and subtropical regions of the Mexican Pacific coast. Species of the genera Gelidium and Pterocladia were found, G. microdentatum and G. pusillum being the most abundant and widely distributed in the Bay. The local and Mexican Pacific distribution for each species is given. The number of species found in this study is compared with the numbers reported in the literature for the Mexican Pacific.     

Distribution Patterns of Strongylocentrotus Sea Urchins along the Coast of Eastern Kamchatka

The distribution patterns of three sea urchin species of the genus Strongylocentrotus in relation to depth, type of substrate, surf action, and to some hydrological parameters were studied along the coast of eastern Kamchatka and in adjacent waters in 1984–1996. The sea urchin Strongylocentrotus polyacanthus dominated the open coast on rocky subintertidal sites with increased surf action and standard oceanic salinity. S. droebachiensis prevailed in shoals with lower salinity, higher water temperature and lower turbulence (enclosed and semienclosed bays). S. pallidus dominated at depths corresponding to the position of the cold intermediate layer deeper than 30–50 m with normal oceanic salinity and lower temperature.     

Zoogeographical classification of the macroparasite faunas of four flatfish species from the northeastern Atlantic

The macroparasite faunas of four righteye flounder species (flounder Platichthys flesus, witch flounder Glyptocephalus cynoglossus, American plaice Hippoglossoides platessoides and Atlantic halibut Hippoglossus hippoglossus) caught off the northern Norwegian coast at 70°N, were classified zoogeographically. The parasite faunas of all four host species were dominated by boreal parasites. This appears to be the situation with the entire area of distribution of these flatfish species. The relationship between the extension of the range of the host species towards the Arctic and the proportion of parasites belonging to the arctic group is indicated.     

Temperature responses of some North AtlanticCladophora species (Chlorophyceae) in relation to their geographic distribution

The temperature responses for growth and survival have been experimentally tested for 6 species of the green algal genusCladophora (Chlorophyceae; Cladophorales) (all isolated from Roscoff, Brittany, France, one also from Connecticut, USA), selected from 4 distribution groups, in order to determine which phase in the annual temperature regime might prevent the spread of a species beyond its present latitudinal range on the N. Atlantic coasts. For five species geographic limits could be specifically defined as due to a growth limit in the growing season or to a lethal limit in the adverse season. These species were: (1)C. coelothrix (Amphiatlantic tropical to warm temperate), with a northern boundary on the European coasts formed by a summer growth limit near the 12°C August isotherm. On the American coasts sea temperatures should allow its occurrence further north. (2)C. vagabunda (Amphiatlantic tropical to temperate), with a northern boundary formed by a summer growth limit near the 15°C August isotherm on both sides of the Atlantic. (3)C. dalmatica, as forC. vagabunda. (4)C. hutchinsiae (Mediterranean-Atlantic warm temperate), with a northern boundary formed by a summer growth limit near the 12°C August isotherm, and possibly also a winter lethal limit near the 6°C February isotherm; and a southern boundary formed by a southern lethal limit near the 26°C August isotherm. It is absent from the warm temperate American coast because its lethal limits, 5° and 30°C, are regularly reached there. (5) Preliminary data forC. rupestris (Amphiatlantic temperate), suggest the southeastern boundary on the African coast to be a summer lethal limit near the 26°C August isotherm; the southwestern boundary on the American coast lies on the 20°C August isotherm. For one species,C. albida, the experimental growth and survival range was wider than expected from its geographic distribution, and reasons to account for this are suggested.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.     

Radial growth and climate responses of white oak (Quercus alba) and northern red oak (Quercus rubra) at the northern distribution limit of white oak in Quebec, Canada

Aim The objectives of this study were: (1) to compare radial growth patterns between white oak (Quercus alba L.) and northern red oak (Quercus rubra L.) growing at the northern distribution limit of white oak; and (2) to assess if the radial growth of white oak at its northern distribution limit is controlled by cold temperature. Location The study was conducted in three regions of the Ottawa valley in southern Québec. All stands selected were located at the northern limit of distribution of Q. alba. Methods Twelve mixed red and white oak stands were sampled and increment cores were extracted for radial growth analyses. For each oak species, 12 chronologies were derived from tree‐ring measurement (residual chronologies). Principal components analysis and redundancy analysis were used to highlight the difference between radial growth in both species and to determine their radial growth–climate association. Results There was little difference between the radial growth of each species; Q. alba, however, exhibits more year‐to‐year variation in growth than Q. rubra. More than 65% of the variance in radial growth was shared among sites and species. Both species showed a similar response to climate, which suggested that the limit of distribution of Q. alba might not be determined by effects on growth. Both species had a classic response to climate and drought in the early growing season. Main conclusions The northern distribution limit of Q. alba does not appear to be directly controlled by effects on growth processes as indicated by the similarities in radial growth and response to climate between the two species. The location of the stands on southern aspects suggested that cold temperature could have been a major factor controlling the distribution limit of Q. alba. However, it is speculated that stands growing on southern aspects may be more prone to forest fires or to drought, which would favour the maintenance and establishment of oaks, and of Q. alba in particular. Models relating the northern distribution limits of species to broad climate parameters like annual mean temperature will need to be reviewed to incorporate more biologically relevant information. Such assessments will in turn provide better estimates of the effect of climate changes on species distribution.     

The effect of temporal variability in salinity on the invasive red alga Gracilaria vermiculophylla

Non-native, invasive species are often characterized by being tolerant to environmental stressors, leaving them more fit relative to native species. The red alga Gracilaria vermiculophylla originates from the NW Pacific but has recently spread along the coastlines of Western Europe, where it has become abundant in many shallow, soft-bottom estuaries. Salinity is important for the local and regional distribution of algae. The distribution of G. vermiculophylla in Europe suggests that it thrives well in hyposaline environments and that it may be more fit than some native algae under such conditions. Little, however, is known about the ecophysiology of G. vermiculophylla and it is therefore difficult to predict its spread and future distribution. Laboratory experiments with G. vermiculophylla showed that steady-state salinity above 15?psu was optimal for growth and that the growth rate was reduced at salinities below 15?psu. Variable salinity reduced the growth rate and larger oscillations were more stressful than small ones. Exposure to very low salinity (0–5?psu) was stressful for the alga and algae exposed to these low levels for 2–4 days were unable to recover fully. Gracilaria vermiculophylla did not seem to perform better in hyposaline conditions than many native, estuarine species. The present distribution of G. vermiculophylla in Scandinavia can be explained well by its response to salinity, but this may not explain its present success relative to many naturally occurring algal species.     

Despite marine traits,the endemic Fucus radicans (Phaeophyceae) is restricted to the brackish Baltic Sea

Many of the marine species that were introduced to the Baltic Sea during the Littorina stage (c. 8500–3000 years BP), e.g. Fucus vesiculosus and F. serratus, have adapted to the present low salinity. These marine species have gone from marine conditions into lower salinity environments. In this paper we ask why the recently discovered endemic brown alga Fucus radicans shows the opposite pattern. Fucus radicans is only present in the northern parts of the Baltic Sea, the low salinity Bothnian Sea (4–6 psu). Potentially, the fitness of F. radicans might be reduced in higher salinities if it is better adapted to brackish conditions. We hypothesize, however, that the southern distribution limit of F. radicans is set by biotic factors, e.g. competition with F. vesiculosus and higher grazing pressure by Idotea balthica and not by salinity. Our results show that the reproductive output of F. radicans is limited by low salinity (4 psu) but increases in higher salinities. However, the southern distribution limit, i.e. the northern Baltic Proper, is regulated by biotic factors, where the additive effects from shading by taller F. vesiculosus thalli and grazing on F. radicans by the isopod I. balthica limit the biomass production of F. radicans. We suggest that F. radicans still maintains marine traits due to its ability to propagate clonally and is restricted to the Bothnian Sea by interactions with F. vesiculosus and I. balthica. We also propose that increased precipitation due to climate change might affect the northern range limit and that the distribution of F. radicans could be expected to shift further south into the Baltic Proper.     

Physiological ecology studies on chilean gelidiales

In the exposed rocky habitats of Central Chile, four species of Gelidium occur along the vertical distance extending from the upper intertidal to the shallow subtidal. The present study was undertaken to characterize taxonomically confused species of Gelidium by differential responses to key ecological factors. In so doing, it was expected to better characterize ecophysiological differences between upper and lower intertidal species and to establish experimental bases on which to compare physiological responses of temperate and subtropical species of Gelidiaceae. The effects of temperature, water movement, salinity, photon flux density and photoperiod were tested on the growth rates of Gelidium pusillum (Stackh.) Le Jol., G. filicinum Bory, G. lingulatum (C. Agardh) J. Agardh and G. spinulosum Kützing prox. With the exception of salinity, specific differences are evident under the effects of all other factors tested.     

Comparison of three gracilarioids: growth rate, agar content and quality

Three gracilarioid species, Gracilariopsis bailiniae and Gracilaria tenuistipitata from Vietnam and Gracilaria gracilis from Russia, were studied in order to determine whether Gracilaria gracilis might be a superior species for cultivation in brackish-water ponds for agar production compared with the Vietnamese species. The effects of different salinity levels on the growth rate and agar production as well as agar properties of three gracilarioid species were compared in controlled laboratory experiments. Gracilaria tenuistipitata and G. gracilis were tolerant to low salinity (∼10‰), whereas Gp. bailiniae died under these conditions. G. tenuistipitata showed superior growth among the three species examined. Gracilaria gracilis had the highest agar content [36.8–46.6% dry weight (dw)]. Agar yield from Vietnamese gracilarioids did not exceed 30% dw. Gel strength of native agar from Gracilaria gracilis was two-fold higher that from Vietnamese species (278 g cm⁻² vs 130 g cm⁻²). Alkali pretreatment increased gel strength significantly for Gracilaria gracilis (1.4-fold), and G. tenuistipitata and Gp. bailiniae (2.3-fold) compared with native agar. The results suggest that Gracilaria gracilis may be a suitable species for production of reasonably good quality agar.     

Physiological responses of Pterocladia and Gelidium (Gelidiales,Rhodophyta) from the Azores,Portugal

Manometric studies were conducted on Pterocladia capillacea, Gelidium latifolium and Gelidium spinulosum from the Azores, Portugal to determine optimal values of temperature, light and salinity for growth. Physiological responses were considered in relation to vertical distribution patterns of these species commonly observed throughout the Azores. Optimal parameters for the growth of Pterocladia capillacea, Gelidium latifolium and G. spinulosum were 17 to 25 °C, a photon flux density between 200 and 300 µmol m^–2 s^–1 and salinities of 25 to 35.     

Recent changes in the distribution of a marine gastropod,Patella rustica Linnaeus, 1758, and their relationship to unusual climatic events

Aim Recent colonization of northern Portuguese shores by Patella rustica Linnaeus, 1758, led to the bridging of a historical gap in the distribution known since the 1900s. Long‐term oceanographic data collected over the last half‐century were examined in order to detect possible mechanisms for the observed change in its distribution. Location This study was carried out along the entire Portuguese coastline, from 41°50′ to 37°06′ N. Time‐series of hydrographical variables (sea surface temperature and salinity) were derived for the Atlantic coast of the Iberian Peninsula. Methods Abundance and size‐frequency distributions of the newly observed limpet populations were compared with those from well‐established populations in southern Portugal. Anomalies were computed for sea surface temperature (1950–2000) and sea surface salinity (1958–2001) data, covering the whole Atlantic coast of the Iberian Peninsula. An upwelling index (1967–2005) was derived for a single location within the distributional gap of P. rustica. Split moving window analysis was performed to detect significant discontinuities in hydrographical data sets. Results Patella rustica has gradually been expanding in northern Iberia, and in the late 1990s the historical gap in distribution in northern Portugal was bridged. Size‐frequency distribution differed between historical and recent populations, the latter lacking small‐sized individuals. At the same time, several anomalous oceanographic events occurred off the Portuguese coast and were probably related to this expansion. Main conclusions Although sea surface temperature might be a major determinant of the reproductive success of P. rustica and hence its dispersal potential, it is more likely that a coincidence of several factors occurring in the late 1990s provided exceptional conditions that allowed the geographical expansion of this species.     

Three new <Emphasis Type="Italic">Ophiostoma</Emphasis> species isolated from Japanese red pine

Three new species of Ophiostoma found on Japanese red pine are described as Ophiostoma pusillum sp. nov., O. botuliforme sp. nov., and O. nigrogranum sp. nov. Ophiostoma pusillum is characterized by oblong ascospores and a Hyalorhinocladiella anamorph. Ophiostoma botuliforme has ostioles covered with a hyaline gelatinous cap, allantoid ascospores, and a Pesotum anamorph with hyaline to pale brown stipes. Ophiostoma nigrogranum has hyaline ostiolar hyphae with rounded tips, allantoid ascospores, and sclerotium-like structures.Contribution no. 172, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba     

Distribution of the introduced amphipod, Caprella mutica Schurin, 1935 (Amphipoda: Caprellida: Caprellidae) on the west coast of Scotland and a review of its global distribution

Caprella mutica Schurin, 1935 was first described from sub-boreal areas of north–east Asia. In less than 40 years C. mutica has spread throughout the northern hemisphere and the first recorded sighting in the southern hemisphere is reported here. Caprella mutica has been introduced to temperate oceanic coasts between latitudes of 25 and 70 °N. Outside its native range, C. mutica has only been found in areas of human activity, including ports, aquaculture facilities and an oilrig; the species has not yet been found in natural habitats. Shipping and aquaculture transfers are the most likely long distance vectors; recreational boating and drifting weed are the most likely short distance vectors. Temperature and salinity do not explain the small-scale distribution of C. mutica on the west coast of Scotland; globally its annual temperature range is 0–22°C. This suggests that the local scale distribution of C. mutica is potentially limited by the availability of suitable transportation vectors during the dispersal phase rather than by physical environmental factors following release.     

Ecological hindcasting of biogeographic responses to climate change in the European intertidal zone

Intertidal organisms are often assumed to live close to their thermal limits, and have emerged as potential early indicators of the effects of climate change. We compared our survey of the 2004–2006 geographic distribution of the barnacle Semibalanus balanoides to its distribution in 1872, 1955, 1963, 1971, and 1985, from surveys by Fischer, Crisp, Fischer-Piette, Barnes, Powell, and Southward. The southern geographic limit has retreated 300 km in France since 1872, at a rate of 15 to 50 km per decade. We compared our 2006 survey of the geographic distribution of the polychaete Diopatra neapolitana to its distribution in 1893–1923, from surveys by Saint-Joseph and Fauvel, and its distribution in 1969–1976 from surveys by Glémarec. The northern geographic limit of this species has advanced 300 km in France since 1893 at similar rates to Semibalanus. We used NOAA weather reanalysis data and our mechanistic simulation model of intertidal animal body temperatures to hindcast the thermal environmental change near historical geographic limits in Europe for the past 55 years. Results indicate that changes in the southern limit of S. balanoides are due to intolerance of winter body temperatures above 10°C, leading to reproductive failure. Results for Diopatra are ambiguous: based on the northern extension of its range, either cold winters or cool summers limit its range, while gaps in its distribution are consistent with limitation by cooler summer conditions. The parallel shifts of D. neapolitana on sedimentary shores and Semibalanus on rocky shores suggest that similar climatic factors control the geographic limits of both species. The intertidal zone is a model system for examining the effects of climate change on biogeographic change both because of the rapidity of its response, and because the rich historical record allows direct tests of hypotheses. Guest editors: J. Davenport, G. Burnell, T. Cross, M. Emmerson, R. McAllen, R. Ramsay & E. Rogan Challenges to Marine Ecosystems     

Growth rates and elemental composition of Alexandrium monilatum, a red-tide dinoflagellate

The combined effects of temperature and salinity on growth of Alexandrium monilatum were studied in laboratory cultures. This toxic, red-tide dinoflagellate grew faster with higher temperatures, up to a maximum of approximately 1 division per day at 31 °C. Salinities above 15 psu had a lesser effect on growth rate, as might be expected for an estuarine species. Growth rates of cultures exposed to natural light and temperature fluctuations were comparable to laboratory cultures. The minimum N cell quota suggested that high N flux would be required to support bloom development. A literature survey of documented A. monilatum blooms indicated that within US waters, blooms occur in July–September in nearshore or estuarine regions of the Gulf of Mexico and the Florida Atlantic coast. Temperature and salinity measured during blooms correspond to the optimal growth conditions of the laboratory cultures. Nevertheless, the occurrence of A. monilatum blooms is sporadic compared to the occurrence of seemingly optimal growth conditions. Laboratory growth experiments predict when blooms of this species are unlikely due to low growth rates, but so far cannot predict individual blooms.     

Northernmost record of the little gulper shark Centrophorus uyato in the north‐eastern Atlantic Ocean,with taxonomical notes on Centrophorus zeehaani

A specimen of the little gulper shark Centrophorus uyato was collected in the Norwegian Sea off the coast of northern Norway, marking the northernmost record of the species in the eastern North Atlantic Ocean. Morphological characteristics collected from the specimen indicate a close relationship to the Australian species Centrophorus zeehaani. DNA barcoding analysis of the mitochondrial cytochrome oxidase subunit I (coI) gene for species of Centrophorus suggests conspecificity of C. uyato and C. zeehaani.     

Competitive exclusion of Cyanobacterial species in the Great Salt Lake

The Great Salt Lake is separated into different salinity regimes by rail and vehicular causeways. Cyanobacterial distributions map salinity, with Aphanothece halophytica proliferating in the highly saline northern arm (27% saline), while Nodularia spumigena occurs in the less saline south (6–10%). We sought to test if cyanobacterial species abundant in the north are competitively excluded from the south, and if southern species are excluded by the high salinity of the north. Autoclaved samples from the north and south sides of each causeway were inoculated with water from each area. Aphanothece, Oscillatoria, Phormidium, and Nodularia were identified in the culture flasks using comparative differential interference contrast, fluorescence, and scanning electron microscopy. Aphanothece halophytica occurred in all inocula, but is suppressed in the presence of Nodularia spumigena. N. spumigena was found only in inocula from the less saline waters in the south, and apparently cannot survive the extremely hypersaline waters of the northern arm. These data suggest that both biotic and abiotic factors influence cyanobacterial distributions in the Great Salt Lake.     

Notes on the distribution ofLepilemur septentrionalis andL. mustelinus in Northern Madagascar

The superfamily Lemuridae, which includes some of the most primitive extant primates, is confined to the island of Madagascar. The speciesL. septentrionalis lives in the north of Madagascar. The geographical distribution of each of the four recognized subspecies is fairly well defined except for the southern limits of the southernmost subspecies, namelyL. s. andrafiamenensis. Similarly the southern and northern limits of distribution ofL. mustelinus are uncertain. Two expeditions were carried out, one in the south of the Andrafiamena mountain chain, the other in the north of the eastern forest, south of Vohemar to gain new information concerning the present southern limits ofL. septentrionalis and northern limit ofL. mustelinus. L. s. andrafiamenensis was found to the left of the Ambilobe-Vohemar road from Betsiaka to Maromokotra and on the left bank of the river Loky, to the coast.L. mustelinus was found only on the right bank of the river Lokoho to the coast. Both survey indicate smaller ranges than those indicated in recent publications, probably a result of continued human encroachment.     

Does salt stress constrain spatial distribution of dune building grasses Ammophila arenaria and Elytrichia juncea on the beach?

Rising sea levels threaten coastal safety by increasing the risk of flooding. Coastal dunes provide a natural form of coastal protection. Understanding drivers that constrain early development of dunes is necessary to assess whether dune development may keep pace with sea‐level rise. In this study, we explored to what extent salt stress experienced by dune building plant species constrains their spatial distribution at the Dutch sandy coast. We conducted a field transplantation experiment and a glasshouse experiment with two dune building grasses Ammophila arenaria and Elytrigia juncea. In the field, we measured salinity and monitored growth of transplanted grasses in four vegetation zones: (I) nonvegetated beach, (II) E. juncea occurring, (III) both species co‐occurring, and (IV) A. arenaria dominant. In the glasshouse, we subjected the two species to six soil salinity treatments, with and without salt spray. We monitored biomass, photosynthesis, leaf sodium, and nutrient concentrations over a growing season. The vegetation zones were weakly associated with summer soil salinity; zone I and II were significantly more saline than zones III and IV. Ammophila arenaria performed equally (zone II) or better (zones III, IV) than E. juncea, suggesting soil salinity did not limit species performance. Both species showed severe winter mortality. In the glasshouse, A. arenaria biomass decreased linearly with soil salinity, presumably as a result of osmotic stress. Elytrigia juncea showed a nonlinear response to soil salinity with an optimum at 0.75% soil salinity. Our findings suggest that soil salinity stress either takes place in winter, or that development of vegetated dunes is less sensitive to soil salinity than hitherto expected.     

Phenology and abundance in relation to climatic variation in a sub-arctic insect herbivore–mountain birch system

The two forest-defoliating geometrid moth species Operophtera brumata and Epirrita autumnata are known to exhibit different altitudinal distribution patterns in northern birch forests. One possible explanation for this is that altitudinal climatic variation differentially affects the performance of two species through mismatching larval and host plant phenology. We explored this hypothesis by investigating the relationship between larval phenology and leaf phenology of Betula pubescens, which is the main host plant of both moth species, along ten replicate altitudinal transects during two springs with contrasting climate in northern Norway. There was a distinct monotonous cline in host plant phenology with increasing altitude in both years of the study, but the development of the leaves were generally 14 days later in the first of the 2 years due to cold spring weather. We found that larval development of both species closely tracked host plant leaf phenology independent of altitude and year. However, at the time of sampling, E. autumnata was approximately one instar ahead of O. brumata at all altitudes, probably reflecting that E. autumnata has faster early instar growth than O. brumata. The abundance of O. brumata was lowest at the altitudinal forest-line, while E. autumnata was lowest near sea level. Our results do not indicate that the altitudinal distribution patterns of the two moth species is due to any phenological mismatch between larval and host plant phenology. We suggest rather that natural enemies at low altitudes limit larval survival and thus abundance of E. autumnata, while an early onset of winter at the forest limit reduces survival of late eclosing adults of O. brumata.