Structure of biological soil crust communities in Callitris glaucophylla woodlands of New South Wales,Australia

Question: What is the nature of the relationships between cover, diversity and abundance of biological soil crusts, cover and diversity of vascular plants, and annual rainfall, soil texture and forestry practices in Callitris glaucophylla woodlands? Location: Arid and semi‐arid Callitris glaucophylla‐domi‐nated woodlands of eastern Australia. Methods: We documented soil crust‐forming mosses, lichens and liverworts at 83 woodland sites along a gradient of declining rainfall. Linear and non‐linear regression were used to examine relationships between soil crust species and attributes of vascular plant communities, and a similarity matrix (species abundance X sites) was subjected to Non‐metric Multi‐Dimensional Scaling (MDS), and Analysis of Similarities (ANOSIM) to show the degree of association between groups of taxa, and soil texture, rainfall classes and forestry practices. Results : We collected 86 taxa. Mosses were dominated by the family Pottiaceae, and lichens were dominated by squamulose forms. Average annual rainfall was highly correlated with soil crust community composition, and loamy soils supported a greater cover and diversity of taxa compared with sandy soils. Increases in tree cover were associated with significant, though weak, increases in abundance, but not diversity, of crusts. Crusts tended to be more diverse in areas that (1) had a sparse cover of ground‐storey plants; (2) were relatively stable ‐ as indicated by the proportion of perennial and/or native plants; (3) had more stable soil surfaces; and (4) were unlogged. Litter cover, overstorey thinning, and livestock grazing had no appreciable effect on crust diversity or cover. Conclusions : Callitris glaucophylla woodlands provide substantial habitat for soil crust organisms, and the dense tree cover and closed canopies of Callitris do not appear to have a major influence on the structure of biological crust communities. Unlike other woodland systems, relatively few patches would be required to reserve a high diversity of crust species.     

Life history of Acrosiphonia (Codiolales, Chlorophyta) in southwestern British Columbia, Canada

This study establishes the phenology of the alternate life history phases of the green alga Acrosiphonia in British Columbia, Canada. Free-living, filamentous plants are seasonal, March-July, with peak percent cover (10%) in April. Plants are fertile immediately after establishment. The unicells, previously identified as Chlorochytrium inclusum and Codiolum petrocelidis, are the sporophyte phase of Acrosiphonia. 'Chlorochytrium,' spherical and 160-280 μm in diameter, colonizes the foliose red alga Mazzaella splendens 1 mo after filamentous Acrosiphonia plants appear. Maximum density (53 'Chlorochytrium' cells/cm(2) of blade) was recorded in May. 'Codiolum,' on the other hand, is stalked (the vesicle measures 150 × 50 μm) and colonizes the red algal crust Petrocelis. Peak density (22?400 'Codiolum' cells/cm(2) of crust) was recorded 2 mo after 'Chlorochytrium' density peaked. The endophytes survive high summer temperatures, which correlate with death of the free-living plants, and overwinter in their hosts. Zoospore release in late winter corresponds to decreased host abundance, suggesting the endophytes have evolved a strategy whereby duration in the host is synchronized with host seasonality. A bet-hedging strategy is proposed for Acrosiphonia's life history: two morphologically different phases have adapted to a seasonally variable environment, with the sporophyte phase capable of colonizing two different hosts.     

Idiosyncratic responses of Pacific salmon species to land cover,fragmentation, and scale

Salmon are critical to the ecology and livelihood of the Pacific Northwest, and are declining throughout much of their range. While much of their life cycle occurs in open ocean, freshwater conditions also contribute to population trends. Because stream habitats are connected to uplands by water flow, salmon can be influenced by the characteristics of terrestrial systems. We analyzed the relationships between the population trends of Pacific salmon (1953–2006) and land cover, fragmentation, and forest age derived from remotely‐sensed, landscape level datasets. Analyses included 425 populations of all native salmon species in 156 watersheds on Vancouver Island, British Columbia, Canada. Vancouver Island salmon escapements exhibited general patterns of decline, which may be largely controlled by broad‐scale marine conditions. The spatial variation in these population trends was related to landscape variables at watershed and riparian scales with regression trees. Results were found to be species specific, but characteristics indicating a legacy of historic and current forest management (such as fragmented forests and non‐forested or early‐successional forest cover) generally had negative effects, driven by a small subset of highly fragmented watersheds. Chum and coho had strong negative relationships with fragmentation, pink had a strong positive relationship with wetland abundance, and Chinook and sockeye were most closely related to geomorphology. There was no ‘single best’ scale of analysis. Salmon trends were generally more closely related to variables estimated over the entire watershed, however, the relative importances of watershed and riparian level predictors varied by both variable and species. Efforts to restore salmon habitat will be complicated by marine and freshwater processes, terrestrial conditions throughout watersheds, and the idiosyncratic requirements of each species.     

Testing for mating isolation between ecotypes: laboratory experiments with lake, stream and hybrid stickleback

Mating isolation is a frequent contributor to ecological speciation – but how consistently does it evolve as a result of divergent selection? We tested for genetically based mating isolation between lake and stream threespine stickleback (Gasterosteus aculeatus L.) from the Misty watershed, Vancouver Island, British Columbia. We combined several design elements that are uncommon in the studies of stickleback mate choice: (i) we used second‐generation laboratory‐reared fish (to reduce environmental and maternal effects), (ii) we allowed for male–male competitive interactions (instead of the typical no‐choice trials) and (iii) we included hybrids along with pure types. Males of different types (Lake, Inlet, hybrid) were paired in aquaria, allowed to build nests and then exposed sequentially to females of all three types. We found that Lake and Inlet males differed in behaviours thought to influence stickleback mate choice (inter‐ and intra‐sexual aggression, display and nest activities), whereas hybrids were either intermediate or apparently ‘inferior’ in these behaviours. Despite these differences, Lake and Inlet fish did not mate assortatively and hybrid males did not have a mating disadvantage. Our study reinforces the noninevitability of mating isolation evolving in response to ecological differences and highlights the need to further investigate the factors promoting and constraining progress towards ecological speciation.     

Dynamics of cryptogamic soil crusts in a derived grassland in south‐eastern Australia

We examined the dynamics of cryptogamic soil crusts in a derived (disclimax) grassland near Orange in south‐eastern Australia. Changes in the cover of cryptogamic crusts and floristics and abundance of the constituent species were measured on four treatments with two levels each of grazing and cultivation. Twenty‐two lichens, mosses and liverworts were found at the study site and, of these, 13 were collected in the quadrats. Three moss species (Barbula calycina, Eccremidium arcuatum and Bryum pachytheca) and one lichen species (Cladonia tessalata) accounted for 67% of total cover‐abundance scores. Generally, cover‐abundance was significantly higher in the unvegetated microsites than in the vegetated microsites. Species richness was not significantly different between the four grazing‐cultivation treatments but, on average, there were significantly more species in the unvegetated microsites (mean = 3.2 species) than in the vegetated microsites (0.54 species). Grazing and cultivation resulted in significantly greater cover of bare ground and consequently significantly greater crust cover. Averaged across all treatments, approximately half of the area of unvegetated soil was occupied by cryptogams. Overall, the results indicate that lichens and bryophytes are important components of derived temperate grasslands, surviving in even densely vegetated swards. This study suggests that strategies which disturb the soil surface (e.g. grazing and cultivation) will stimulate the abundance and cover of soil crust organisms by increasing the availability of unvegetated microsites.     

Population genetic isolation and limited connectivity in the purple finch (Haemorhous purpureus)

Using a combination of mitochondrial and z‐linked sequences, microsatellite data, and spatio‐geographic modeling, we examined historical and contemporary factors influencing the population genetic structure of the purple finch (Haemorhous purpureus). Mitochondrial DNA data show the presence of two distinct groups corresponding to the two subspecies, H. p. purpureus and H. p. californicus. The two subspecies likely survived in separate refugia during the last glacial maximum, one on the Pacific Coast and one east of the Rocky Mountains, and now remain distinct lineages with little evidence of gene flow between them. Southwestern British Columbia is a notable exception, as subspecies mixing between central British Columbia and Vancouver Island populations suggests a possible contact zone in this region. Z‐linked data support two mitochondrial groups; however, Coastal Oregon and central British Columbia sites show evidence of mixing. Contemporary population structure based on microsatellite data identified at least six genetic clusters: three H. p. purpureus clusters, two H. p. californicus clusters, and one mixed cluster, which likely resulted from high site fidelity and isolation by distance, combined with sexual selection on morphological characters reinforcing subspecies differences.     

LIFE HISTORY AND HYBRIDIZATION STUDIES ON GIGARTINA STELLATA AND PETROCELIS CRUENTA (RHODOPHYTA) IN THE NORTH ATLANTIC1

Fourteen isolates of the crustose marine red alga Petrocelis cruenta J. Agardh from various localities in the British Isles, France (including the type locality), Spain and Portugal gave rise in culture to dioecious foliose plants identifiable as Gigartina stellata (Stackhouse) Batters although two isolates formed only sterile foliose blades. A total of 145 isolates of Gigartina stellata were also grown in culture from various localities in the U.S.A. (Maine), the British Isles, Iceland, Denmark, France, Spain and Portugal using both carpospores and vegetative blade apices. Two basic types of life history were found among these isolates: a direct-type life history involving the formation of further foliose plants from carpospores, some isolates of which also form spermatangia on the same papillae as the cystocarps; and a heteromorphic-type in which only crustose plants resembling Petrocelis cruenta are formed from carpospores. Only heteromorphic-type life histories were found from Spain and Portugal. Both life history types were found in plants from the U.S.A., the British Isles and northern France. Only direct-type life histories were found in plants from Iceland and Denmark. Some Petrocelis-like crusts derived from field collected G. stellata carpospores and Petrocelis crusts of hybrid progeny formed tetrasporangia in 8:16 h LD, 10° C but not in 8:16 h LD, 15° C; 16:8 h LD 10° C or 15° C; and 10:6.5:1: 6.5 h LDLD, 10° C. The spores thus formed were viable and produced normal dioecious male and female gametophytes. Short day and low temperature conditions appear necessary for tetrasporogenesis. The results from crossing experiments with 32 male and 27 female isolates of the heteromorphic-type derived from both G. stellata and P. cruenta showed that two virtually non-interbreeding populations with a high degree of geographical separation exist in the north-eastern Atlantic. Morphological differences between plants from each population are described. On the basis of culture and crossing results, Petrocelis cruenta J. Agardh is placed in synonymy with Gigartina stellata (Stackhouse in Withering) Batters.     

Redefining the Ethnographic Object: An Anthropology Museum Turns Fifty

Exhibit A: Objects of Intrigue. Museum of Anthropology, University of British Columbia, Vancouver, March 9, 1999–March 31, 2000.
Objects and Expressions: Celebrating the Collections of the Museum of Anthropology at the University of British Columbia. Vancouver: Museum of Anthropology, University of British Columbia, 1999.     

Distribution of diatom surface sediment assemblages within Effingham Inlet, a temperate fjord on the west coast of Vancouver Island (Canada)

Twenty-nine surface sediment samples from Effingham Inlet, a small fjord on the west coast of Vancouver Island, British Columbia, were analyzed for diatoms. This fjord has been selected for paleoceanographic investigation due to the presence of laminated sediments resulting from the dysoxic to anoxic bottom water conditions in the inner and outer basins of the inlet. Distributional patterns of the diatom microflora reflected proximity to littoral regions, phytoplankton production, and marine influence from outside the fjord. Principal components and cluster analyses of the microflora established four diatom assemblages with a clear separation between the inner and outer basin diatom floras. Inner basin stations were characterized by elevated absolute abundance with assemblages dominated by spring–early summer bloom taxa including Skeletonema costatum, Thalassiosira nordenskioeldii, and Thalassiosira pacifica. Chaetoceros spp. resting spores were abundant throughout Effingham Inlet, with the exception of the stations closest to the fjord head. Stations located in the outer basin and towards the fjord mouth had relatively lower absolute abundance yet showed a higher relative and absolute abundance of Thalassionema nitzschioides, Rhizosolenia setigera, Coscinodiscus radiatus, Ditylum brightwellii, Odontella longicruris, and Paralia sulcata in relation to the inner basin. Many of these latter taxa are often associated with late summer and autumn conditions in fjords along coastal British Columbia. Oceanographic data for Effingham Inlet suggest that increased offshore penetration is more likely to occur from summer to early fall, with a more restricted offshore influence in the inner basin. Diatom surface sediment assemblages in Effingham Inlet appear to reflect incursions of offshore waters into the fjord. Absolute abundance estimates and the preservation of lightly silicified taxa suggest excellent preservation of fossil material in the sediments of the predominantly anoxic inner basin. Preservation in the outer basin is reduced, reflecting more frequent recharge by oxygenated waters spilling over the outer sill into the basin. Our findings suggest the inner basin should be an optimal site for reconstruction of diatom production, with records from the outer basin providing more consistent information about offshore influence and coastal upwelling conditions over the Holocene. Estimates of diatom abundance within the inner basin sediment may serve as a good proxy of production, although proxy tracers of bottom water conditions and sedimentological analyses must be coupled to the diatom record to ensure depositional conditions were not influencing valve preservation or abundance. Our results suggest that fjords can serve as good environments for paleoceanographic reconstructions of both inshore and offshore conditions although careful site selection and understanding of processes affecting the microfossil record are essential.     

The 8th International Conference of the Canadian Proteomics Initiative

The 8th International Conference of the Canadian Proteomics Initiative (CPI) was held at the Hilton Vancouver Metrotown Hotel in Burnaby, British Columbia from 3–5 May, 2008. With nearly 200 delegates, 32 speakers and more than 50 poster presentations, CPI 2008 covered a wide range of topics, including novel technologies, human and clinical proteomics, structural proteomics, bioinformatics, post-translational modifications, membrane and receptor proteomics, and plant and animal proteomics. This year’s conference was also highlighted by hands-on proteomics workshops at the University of Victoria Genome BC Proteomics Centre and the University of British Columbia, an inaugural meeting of the British Columbia Proteomics Network and focus meetings exploring opportunities for the formation of a nationwide association for Canadian proteomics and Genome British Columbia’s efforts towards large-scale global genomics and proteomics projects.     

Intercontinental genetic structure in the amphi‐Pacific peatmoss Sphagnum miyabeanum (Bryophyta: Sphagnaceae)

Unlike seed plants where global biogeographical patterns typically involve interspecific phylogenetic history, spore‐producing bryophyte species often have intercontinental distributions that are best understood from a population genetic perspective. We sought to understand how reproductive processes, especially dispersal, have contributed to the intercontinental ‘Pacific Rim’ distribution of Sphagnum miyabeanum. In total, 295 gametophyte plants from western North America (California, Oregon, British Columbia, Alaska), Russia, Japan, and China were genotyped at 12 microsatellite loci. Nucleotide sequences were obtained for seven anonymous nuclear loci plus two plastid regions from 21 plants of S. miyabeanum and two outgroup species. We detected weak but significant genetic differentiation among plants from China, Japan, Alaska, British Columbia, and the western USA. Alaskan plants are genetically most similar to Asian plants, and British Columbian plants are most similar to those in the western USA. There is detectable migration between regions, with especially high levels between Alaska and Asia (China and Japan). Migration appears to be recent and/or ongoing, and more or less equivalent in both directions. There is weak (but significant) isolation‐by‐distance within geographical regions, and the slope of the regression of genetic on geographical distance differs for Asian versus North American plants. A distinctive Vancouver Island morphotype is very weakly differentiated, and does not appear to be reproductively isolated from plants of the normal morphotype. The intercontinental geographical range of S. miyabeanum reflects recent and probably ongoing migration, facilitated by the production of tiny spores capable of effective long distance dispersal. The results of the present study are consistent with Pleistocene survival of S. miyabeanum in unglaciated Beringia, although we cannot eliminate the possibility that the species recolonized Alaska from Asia more recently. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 17–37.     

Estimating Carrying Capacity for Sea Otters in British Columbia

ABSTRACT We estimated carrying capacity for sea otters (Enhydra lutris) in the coastal waters of British Columbia, Canada, by characterizing habitat according to the complexity of nearshore intertidal and sub-tidal contours. We modeled the total area of complex habitat on the west coast of Vancouver Island by first calculating the complexity of the Checleset Bay-Kyuquot Sound (CB-KS) region, where sea otters have been at equilibrium since the mid-1990s. We then identified similarly complex areas on the west coast of Vancouver Island (WCVI model), and adapted the model to identify areas of similar complexity along the entire British Columbia coast (BC model). Using survey data from the CB-KS region, we calculated otter densities for the habitat predicted by the 2 models. The density estimates for CB-KS were 3.93 otters/km² and 2.53 otters/km² for the WCVI and BC models, respectively, and the resulting 2 estimates of west coast of Vancouver Island complex habitat carrying capacity were not significantly different (WCVI model: 5,123, 95% CI = 3,337–7,104; BC model: 4,883, 95% CI = 3,223–6,832). The BC model identified the region presently occupied by otters on the central British Columbia coast, but the amount of coast-wide habitat it predicted (5,862 km²) was relatively small, and the associated carrying capacity estimate (14,831, 95% CI = 9,790–20,751) was low compared to historical accounts. We suggest that our model captured a type of high-quality or optimum habitat prevalent on the west coast of Vancouver Island, typified by the CB-KS region, and that suitable sea otter habitat elsewhere on the coast must include other habitat characteristics. We therefore calculated a linear, coast-wide carrying capacity of 52,459 sea otters (95% CI = 34,264–73,489)—a more realistic upper limit to sea otters in British Columbia. Our carrying capacity estimates are helping set population recovery targets for sea otters in Canada, and our habitat predictions represent a first step in Critical Habitat identification. This habitat-based approach to estimating carrying capacity is likely suitable for other nonmigratory, density-dependent species.     

Patterns of gametophyte dominance ofIridaea splendens(Rhodophyta) in Vancouver Harbour,Vancouver, British Columbia,Canada

This paper presents results of field and laboratory work on one component of population structure ofIridaea splendens (Setchellet Gardner) Papenfuss (Gigartinaceae, Rhodophyta), the seasonal change in abundance of the gametophyte life-history stage. Investigations of this genus by others (using a variety of sampling and identification techniques) have shown a seasonal gametophyte dominance, sporophyte dominance, or some combination of these two. Gametophyte stages ofIridaea splendens produce kappa carrageenan and tetrasporophyte stages lambda carrageenan; a chemical colorimetric test using resorcinol can be used to identify these stages regardless of the presence of reproductive structures. In this paper we report on the proportion of gametophytes determined both by this chemical test and by the presence of reproductive structures, and on one possible determinant of the seasonal change in dominance. Analysis of field samples using the resorcinol test showed that from June–August the gametophyte stage predominates and from December–February the tetrasporaphyte stage is most common, both in reproductive and non-reproductive thalli (the latter tested as three size classes). Examination of reproductive structures gave similar results. One factor suggested in the literatures as a possible determinant of the haploid/diploid ratio is apomeiosis (in the formation of the tetraspores); our results show this to be unimportant in the Vancouver Harbor populations.Presented at the XIIIth International Seaweed Symposium, University of British Columbia, Vancouver, Canada, August 1989.     

LIFE HISTORIES IN THE PHYLLOPHORACEAE (RHODOPHYTA: GIGARTINALES) FROM THE PACIFIC COAST OF NORTH AMERICA. I. GYMNOGONGRUS LINEARIS AND G. LEPTOPHYLLUS1

Carpospores of Gymnogongrus linearis (C. Ag.) J. Ag. collected from Sonoma Co., California were cultured and gave rise to crustose plants. Tetrasporogenesis could not be induced. However, tetraspores from field-collected crustose tetrasporophytes found near G. linearis from San Mateo Co., California were cultured. These field crusts superficially resemble Petrocelis middendorffii (Ruprecht) Kjellman, but differ in size, color, number of tetrasporangia per filament, and distal dichotomous branching of the perithallial filaments. Tetraspores gave rise to upright plants identical to G. linearis. Gymnogongrus leptophyllus J. Ag. collected from California and Baja California, Mexico were found as narrow and wide forms. Narrow form isolates recycled directly without producing a crustose tetrasporophyte. These are interpreted as apogamous. Carpospores of the wide form grew into crusts resembling Petrocelis (=Erythrodermis) haematis Hollenberg. Tetrasporogenesis was induced in culture by abrasion or dehydration. Tetraspores from field-collected crusts and laboratory cultured tetrasporophytes grew into plants identical to G. leptophyllus, completing a sexual life history with an alternation of heteromorphic generations.     

INTRASPECIFIC VARIATION IN ABIES LASIOCARPA FROM BRITISH COLUMBIA AND WASHINGTON

Sixteen natural stands of Abies lasiocarpa (Hook.) Nutt. were sampled from British Columbia and Washington to investigate patterns of intraspecific variation in this species and to evaluate Hunt and von Rudloff's recognition of two species of subalpine fir. Principal components analysis and canonical variates analysis were performed separately on seed-cone data, needle morphology data, and needle flavonoid data. Analysis of cone data indicated no geographical patterning of populations, but eastern and western groups of populations were segregated in both the needle morphology and flavonoid analyses. With the exception of the Vancouver Island population, three geographic groups were discerned based on their needle morphology: 1) populations from the coastal mountains of British Columbia, 2) those from the Cascade Mountains of Washington, and 3) those from the eastern interior of British Columbia. Although the Vancouver Island population was grouped with the interior British Columbia populations based on needle morphology, it was similar to the other coastal populations based on flavonoid data. These inconsistent results among the three different types of taxonomic evidence underscore the need to consider a variety of traits when drawing taxonomic conclusions in Abies. Although the delineation of eastern and western groups is not wholly consistent for the different data sets, the results support recognition of coastal and interior varieties of subalpine fir.     

The distribution of divergent mitochondrial DNA lineages of threespine stickleback (Gasterosteus aculeatus) in the northeastern Pacific Basin: post-glacial dispersal and lake accessibility

Aim This study furthers the documentation of the geographical distribution of two divergent (c. 3%) mitochondrial DNA clades in the threespine stickleback (Gasterosteus aculeatus) and tests the hypotheses that the northeastern Pacific distribution has been influenced by post‐glacial colonization and lake elevation and that clade identity is associated with certain morphological attributes such as reduction in body armour. Location Lakes and nearshore marine environments of the eastern Pacific Basin from southcentral Alaska to southeastern British Columbia, (BC) Canada. Methods Restriction enzyme analysis of polymerase chain reaction‐amplified mitochondrial DNA fragments (cytochrome b) from a total of 45 new populations combined with existing data for a further 45 populations. Lake elevation data were collected for 78 localities and tested for an association with mtDNA clade by contingency table analyses. Morphological data were collected on sticklebacks from eight samples representing four lake‐stream systems and tested for differentiation among populations with different mtDNA clade identities using analyses of variance. Results We extend the known distribution of the haplotypes diagnostic of the Trans‐North Pacific Clade (TNPC) southward to mid‐Vancouver Island and, for the first time, on mainland BC, in other island populations far from putative refugia, and in nearby anadromous populations. A morphological analysis indicated that the mainland population with the TNPC was not characterized by reduced spine or lateral plate (‘armour’) traits that characterize some putative relict populations on the Queen Charlotte Islands. We found a significant association between lake elevation and the presence of the TNPC; the TNPC was present more often in lakes located at or lower than 42 m than in higher elevation lakes. Main conclusions Our data support the hypothesis that post‐glacial colonization by TNPC‐bearing marine sticklebacks and aspects of lake ‘accessibility’ were important in determining the distribution of mtDNA clades in the eastern Pacific Ocean basin. More generally, our study demonstrates how processes acting both across immense geographic scales (e.g. pan‐Pacific dispersal) and local scales (lake accessibility contingent on timing and extent of isostatic rebound) may interact to explain biogeographical patterns.     

Clones or clans: the genetic structure of a deep‐sea sponge,Aphrocallistes vastus,in unique sponge reefs of British Columbia,Canada

Understanding patterns of reproduction, dispersal and recruitment in deep‐sea communities is increasingly important with the need to manage resource extraction and conserve species diversity. Glass sponges are usually found in deep water (>1000 m) worldwide but form kilometre‐long reefs on the continental shelf of British Columbia and Alaska that are under threat from trawling and resource exploration. Due to their deep‐water habitat, larvae have not yet been found and the level of genetic connectivity between reefs and nonreef communities is unknown. The genetic structure of Aphrocallistes vastus, the primary reef‐building species in the Strait of Georgia (SoG) British Columbia, was studied using single nucleotide polymorphisms (SNPs). Pairwise comparisons of multilocus genotypes were used to assess whether sexual reproduction is common. Structure was examined 1) between individuals in reefs, 2) between reefs and 3) between sites in and outside the SoG. Sixty‐seven SNPs were genotyped in 91 samples from areas in and around the SoG, including four sponge reefs and nearby nonreef sites. The results show that sponge reefs are formed through sexual reproduction. Within a reef and across the SoG basin, the genetic distance between individuals does not vary with geographic distance (r = ?0.005 to 0.014), but populations within the SoG basin are genetically distinct from populations in Barkley Sound, on the west coast of Vancouver Island. Population structure was seen across all sample sites (global F_ST = 0.248), especially between SoG and non‐SoG locations (average pairwise F_ST = 0.251). Our results suggest that genetic mixing occurs across sponge reefs via larvae that disperse widely.     

Microbial crusts of the late jurassic: Composition,palaeoecological significance and importance in reef construction

Summary Upper Jurassic reefs contain variable amounts of calcareous microbial crusts. In examples from Portugal, Spain and southern Germany they occur within coral biostromes and bioherms, mixed coral-siliceous sponge reefs, siliceous sponge meadows and mudmounds, and build up thrombolities with or without additional reef metazoans. The crusts are of paramount importance for the establishment and development of positive buildups. Commonly, reef growth starts with crusts which develop from a narrow base and rapidly expand laterally by rising above the sea floor. Reef associations with little or no microbial crust normally did not develop distinct relief. The basic microbial crust type is characterised by a dense to peloidal, mostly clotted, hence thrombolitic fabric which developed due to calcification triggered by microbes. Morphological evidence for this organic nature are positive relief, bridge-structures, and the shape and arrangement of peloids. The basic thrombolitic crust type is a eurytopic feature, equally occurring in settings of different bathymetry, waterenergy, salinity and oxygen/nutrient concentrations. However, the crusts also comprise additional micro-encrusters of variable abundance and diversity. The concurrent occurrence of these encrusters and diversity trends allows discrimination between crusts of different environments, particularly of different water depths. Microbial crusts from non-reefal marine oncoids show both similarities and differences with reefal crusts. For some of the mostly enigmatic micro-encrusters new clues to their nature could be detected. For instance, bubble-like structures, formerly interpreted as sporangia inLithocodium could be identified as the foraminiferBullopora aff.laevis, possibly living as a parasite or symbiont in theLithocodium algal tissue.Lithocodium andBacinella are regarded as different organisms.‘Tubiphytes’ morronensis clearly represents a symbiotic intergrowth between a nubeculinellid foraminifer and a microbe of unknown nature. The main prerequisite for the occurrence of microbial crusts is a cessation of background sedimentation which commonly can be tied to rises in sea level. This results in the development of crust-rich reefs. Fluctuations in oxygen and nutrient levels are indicated by dysaerobic bivalves and richness in authigenic glauconite, and led to the microbes outcompeting reefal metazoans, and to the development of thrombolites. Such thrombolites occur at very different depths which is interpreted to be related to a rise of dysaerobic waters due to climatic buffering and lowering of oceanic circulation during sea level rises. Microbial crusts in modern reefs are largely restricted to shaded, cryptic settings which contrasts with the wide distribution of crusts in Upper Jurassic reefs. Microbial crusts were increasingly replaced by coralline red algae since the Late Mesozoic, but despite their restricted modern habitat seem to still play an important, commonly overlooked role in the stabilisation of reef framework.     

Seed dispersal facilitation and geographic consistency in bird–fruit abundance patterns

Avian seed dispersal mutualisms are characterized frequently by stochastic interactions between birds and fruits; however, many studies report coarse‐scale correlations in annual abundances of birds and fruits at particular locales (i.e. ‘phenological synchrony’). This study tested the geographical consistency of phenological synchrony in a meta‐analysis of data from 14 biogeographic locations. Data from a single site in British Columbia, Canada, were then used to test the dispersal facilitation hypothesis, which postulates that synchronous bird–fruit abundance patterns result from deterministic seed dispersal processes (i.e. avian fruit consumption). Results showed that phenological synchrony is a geographically consistent pattern. However, fruit production occurred after peak periods of bird abundances in British Columbia. Although phenological patterns were asynchronous at this site, observational and experimental fruit removal patterns supported the dispersal facilitation hypothesis. Avian fruit consumption covaried with bird abundances, suggesting selection may favour earlier fruit production and increased phenological synchrony. Environmental data suggest that earlier fruit production is constrained by cold spring temperatures, which inhibit the activity of pollinators and earlier dates of fruit maturation. Overall, the results show that phenological synchrony is a geographically consistent pattern in seed dispersal mutualisms. However, decoupled bird–fruit abundance patterns may occur despite deterministic processes favouring phenological synchrony.     

A new methodology for reconstructing climate and vegetation from modern pollen assemblages: an example from British Columbia

Aim We used modern pollen assemblages to develop a method for climate reconstruction that reduces the spatial autocorrelation of residuals and accounts for the strong topographic and climatic variation that occurs in British Columbia, Canada. Location British Columbia, Canada, including sites both on the mainland and on adjacent islands (Queen Charlotte Islands and Vancouver Island). Methods New pollen assemblages from surface‐sediment samples collected in British Columbia were combined with other published and unpublished samples (n = 284). Multivariate rank‐distances between sample sites and a randomized set of sites within the province were calculated for climate parameters to determine whether gaps in the current network of present‐day pollen sample sites exist. Lacustrine surface‐sediment pollen assemblages (n = 145) were ordinated using non‐metric multidimensional scaling (NMDS), and a generalized additive model (GAM) was used to reconstruct modern mean warmest month temperature (MWMT) and mean annual precipitation (MAP) from the NMDS ordination. The results were compared with standard climate reconstruction techniques, including the modern analogue technique, partial least squares, weighted averaging, weighted averaging–partial least squares and factor analysis. Results Reconstructions of MWMT and MAP using NMDS and GAM were comparable to those of existing models. When reconstructing MWMT, the NMDS/GAM method had a lower root‐mean‐squared error of prediction (RMSEP), lower spatial autocorrelation and higher correlation with observed temperature values than the other methods tested. When reconstructing MAP, the partial least squares method performed better than the NMDS/GAM method for RMSEP and correlation with observed values; however, the NMDS/GAM method had a lower spatial autocorrelation of residuals. Main conclusions NMDS reveals strong relationships among modern pollen assemblages, vegetation and climate parameters. Climate models using NMDS and GAM are comparable to other palaeoecological reconstruction models, but provide lower spatial autocorrelation of residuals for both parameters tested. An inverse distance‐weighted surface of multivariate rank‐climate distances generated from the network of pollen sample sites indicates that greater sampling intensity in north‐western and central‐interior British Columbia is required in order to obtain an accurate representation of climatic and vegetation diversity in the province.