Population dynamics of coniferous and broad-leaved trees in a Japanese temperate mixed forest

The growth and survival of coniferous and broad-leaved trees were followed over a 5-yr period in a temperate old-growth mixed forest in Japan, and dynamic features of the forest were studied in relation to the life history of the dominants, the coniferous Abies homolepis and the broad-leaved Fagus crenata. During this period, the gap formation rate was 31m² ha^?1yr^?1, the mortality of trees > 2m high was 1.7%/yr, and the rate of loss in basal area 1.4%/yr. These values were much higher than the recruitment, 0.3%/yr, and the total growth of surviving and new trees, 0.6%/yr, owing to the inhibition of regeneration by understorey dwarf bamboo (Sasa borealis). A transition matrix model based on DBH size classes predicts that the basal area of the forest will decrease by 14% in 50 yr, but that the DBH distribution of trees > 10 cm diameter will change little. Equilibrium DBH distributions assuming recruitment being equal to mortality, were quite different between broad-leaved and coniferous trees, reflecting different survivorship curves of the two dominants. The composition and structure of the forest may change depending on the pattern and frequency of disturbances, or episodic events, notably the synchronous death of Sasa borealis.     

Multi-Scale Assessment of Male Northern Yellow Bat Roost Selection

Knowledge of roost selection by northern yellow bats (Lasiurus intermedius) is limited to a small number of known roost locations. Yet knowledge of basic life history is fundamental to understanding past response to anthropogenic change and to predict how species will respond to future environmental change. Therefore, we examined male northern yellow bat roost selection on 2 Georgia, USA, barrier islands with different disturbance histories. Sapelo Island has a history of extensive disturbance and is dominated by pine (Pinus spp.) forests; Little Saint Simons Island has a limited disturbance history with maritime oak (Quercus spp.) forest as the dominant cover type. From March–July 2012 and 2013, we radio-tracked 35 adult male northern yellow bats to diurnal roosts and modeled roost characteristics at the plot and landscape scales. We located 387 roosts, of which 95% were in Spanish moss (Tillandsia usneoides) hanging in hardwood trees. On both islands, bats selected roost trees with larger diameters than surrounding trees and selected roost locations with greater open flight space (i.e., low midstory clutter) underneath. Roosts were located farther from open areas on Sapelo and closer to fresh water on Little Saint Simons compared to random locations. Lower availability of hardwood forest on Sapelo may have resulted in small-scale roost site selection (i.e., plot level) despite potential increased costs of commuting to water and open areas for foraging. In contrast, greater availability of hardwood forest on Little Saint Simons likely allowed selection of roosts closer to fresh water, which provides foraging and drinking opportunities. Our results indicate that mature hardwood trees in areas with low midstory clutter are important in male northern yellow bat roost selection, but landscape-level features have varying influences on roost selection, likely as a result of differences in disturbance history. Therefore, management will differ depending on the landscape context. Further research is needed to examine roost selection by females, which may have different habitat requirements. © 2020 The Wildlife Society.     

Maintenance and recovery of rare clonal plants: the Case of the twinflower (Linnaea borealis L.)

Summary

Populations of rare clonally spreading species are increasingly being shown to be composed of one or a few genotypes. Clones have potentially unlimited life but two factors, genetic erosion due to random events and increasing accumulation of genetic load in older genotypes, combine to expose them to sexual failure and loss of fertility. Non-breeding clonal populations are at risk of extinction because they lack the ability to adapt or escape from changing environments.

Twinflower (Linnaea borealis L.) has been lost from nearly 50 % of its pre-1970 sites. It is a clonal self-incompatible plant and sexual failure has been reported from Canada, Britain and Scandinavia. Sexual failure is due to high levels of within-clone pollination by flies. Seed set occurs naturally in Scottish populations which have some genetic diversity. A non-breeding population in Scotland has been restored to viability by experimental cross-pollination with pollen from a distant source. Conservation action for this species should therefore be directed to the prevention of loss of habitat and restoration of population viability by translocation of compatible mates.

Translocating plants into extant, but non-breeding, populations are still a matter of debate and are frequently opposed. However, experimental translocations must now be performed to establish whether intervention can secure the long-term survival of rare clonal plants without the constant need for re-introduction.     

What Happened before Losses of Photosynthesis in Cryptophyte Algae?

In many lineages of algae and land plants, photosynthesis was lost multiple times independently. Comparative analyses of photosynthetic and secondary nonphotosynthetic relatives have revealed the essential functions of plastids, beyond photosynthesis. However, evolutionary triggers and processes that drive the loss of photosynthesis remain unknown. Cryptophytes are microalgae with complex plastids derived from a red alga. They include several secondary nonphotosynthetic species with closely related photosynthetic taxa. In this study, we found that a cryptophyte, Cryptomonas borealis, is in a stage just prior to the loss of photosynthesis. Cryptomonas borealis was mixotrophic, possessed photosynthetic activity, and grew independent of light. The plastid genome of C. borealis had distinct features, including increases of group II introns with mobility, frequent genome rearrangements, incomplete loss of inverted repeats, and abundant small/medium/large-sized structural variants. These features provide insight into the evolutionary process leading to the loss of photosynthesis.     

Mass spectrometric investigation of the neuropeptide complement and release in the pericardial organs of the crab, Cancer borealis

The crustacean stomatogastric ganglion (STG) is modulated by both locally released neuroactive compounds and circulating hormones. This study presents mass spectrometric characterization of the complement of peptide hormones present in one of the major neurosecretory structures, the pericardial organs (POs), and the detection of neurohormones released from the POs. Direct peptide profiling of Cancer borealis PO tissues using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) revealed many previously identified peptides, including proctolin, red pigment concentrating hormone (RPCH), crustacean cardioactive peptide (CCAP), several orcokinins, and SDRNFLRFamide. This technique also detected corazonin, a well-known insect hormone, in the POs for the first time. However, most mass spectral peaks did not correspond to previously known peptides. To characterize and identify these novel peptides, we performed MALDI postsource decay (PSD) and electrospray ionization (ESI) MS/MS de novo sequencing of peptides fractionated from PO extracts. We characterized a truncated form of previously identified TNRNFLRFamide, NRNFLRFamide. In addition, we sequenced five other novel peptides sharing a common C-terminus of RYamide from the PO tissue extracts. High K+ depolarization of isolated POs released many peptides present in this tissue, including several of the novel peptides sequenced in the current study.     

Cross-reactivity of some antibodies to human epitopes with shrimp Pandalus borealis proteins: a possible aid in validation and characterization of crustacean cells in vitro

Cell characterization of primary cultures in vertebrates is well established but not in marine invertebrates. This fact is hampering advances in the development of tissue cultures from this species. In the present study, a panel of antibodies to structural proteins, stress proteins, oncogenes and proliferation antigens, developed against mammalian antigens, were tested in paraffin sections of the crustacean Pandalus borealis tissues. Several tissues were analysed: hepatopancreas, gills, ovaries, epithelium under the cuticle and abdominal muscle. Specific antibodies to crustacean proteins are not commercially available. The immunocytochemical results show that antibodies to human epitopes cross-react with antigens in the crustacean Pandalus borealis indicating that some cellular proteins are highly conserved in evolution. Cytokeratin, proliferating cell nuclear antigen, ras and p-glycoprotein were detected by immunocytochemistry in Pandalus borealis. No immunoreactivity for Ki-67 and metallothionein was observed. This system can help in validation and characterization of invertebrate cultures.     

Genetic differentiation amongst fragrant orchids (Gymnadenia conopsea s.l.) in the British Isles

Genetic variation was examined in five microsatellite loci to seek evidence of genetic differentiation and restricted gene flow that would support the taxonomic division of Gymnadenia into three species ( G. borealis , G. conopsea , and G. densiflora ). A total of 107 alleles was detected in 17 populations from England, Scotland, and Ireland. The mean expected heterozygosities ranged from 0.48 to 0.81. The differentiation in allele frequencies amongst populations that had been assigned to each taxon on the basis of morphology was sufficiently large to support the taxa as distinct species. Phylogenetic trees based on microsatellite allele frequencies, as well as assignment tests, supported the existence of three distinct groups with at least partial restriction of gene flow between them. There was substantial homozygote excess, leading to high F _IS estimates, for most loci in most populations. This is unlikely to have been a result of widespread null alleles, and more probably reflects a high level of inbreeding in G. conopsea . This inference requires further investigation. The implications of the results of this and other taxonomic studies for the conservation of Gymnadenia in Britain are discussed.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 349–360.     

Identification, physiological actions, and distribution of TPSGFLGMRamide: a novel tachykinin-related peptide from the midgut and stomatogastric nervous system of Cancer crabs

In most invertebrates, multiple species-specific isoforms of tachykinin-related peptide (TRP) are common. In contrast, only a single conserved TRP isoform, APSGFLGMRamide, has been documented in decapod crustaceans, leading to the hypothesis that it is the sole TRP present in this arthropod order. Previous studies of crustacean TRPs have focused on neuronal tissue, but the recent demonstration of TRPs in midgut epithelial cells in Cancer species led us to question whether other TRPs are present in the gut, as is the case in insects. Using direct tissue matrix assisted laser desorption/ionization Fourier transform mass spectrometry, in combination with sustained off-resonance irradiation collision-induced dissociation, we found that at least one additional TRP is present in Cancer irroratus, Cancer borealis, Cancer magister, and Cancer productus. The novel TRP isoform, TPSGFLGMRamide, was present not only in the midgut, but also in the stomatogastric nervous system (STNS). In addition, we identified an unprocessed TRP precursor APSGFLGMRG, which was detected in midgut tissues only. TRP immunohistochemistry, in combination with preadsorption studies, suggests that APSGFLGMRamide and TPSGFLGMRamide are co-localized in the stomatogastric ganglion (STG), which is contained within the STNS. Exogenous application of TPSGFLGMRamide to the STG elicited a pyloric motor pattern that was identical to that elicited by APSGFLGMRamide, whereas APSGFLGMRG did not alter the pyloric motor pattern.