ALBERT

Description: Evidence is accumulating that species’ responses to climate changes are best predicted by modelling the interaction of physiological limits, biotic processes and the effects of dispersal-limitation. Using commercially harvested blacklip ( Haliotis rubra ) and greenlip abalone ( H. laevigata ) as case studies, we determine the relative importance of accounting for interactions among physiology, metapopulation dynamics and exploitation in predictions of range (geographical occupancy) and abundance (spatially explicit density) under various climate change scenarios. Traditional correlative ecological niche models (ENM) predict that climate change will benefit the commercial exploitation of abalone by promoting increased abundances without any reduction in range size. However, models that account simultaneously for demographic processes and physiological responses to climate-related factors result in future (and present) estimates of area of occupancy and abundance that differ from those generated by ENMs alone. Range expansion and population growth are unlikely for blacklip abalone because of important interactions between climate-dependent mortality and metapopulation processes; in contrast, greenlip abalone should increase in abundance despite a contraction in area of occupancy. The strongly non-linear relationship between abalone population size and area of occupancy has important ramifications for the use of ENM predictions that rely on metrics describing change in habitat area as proxies for extinction risk. These results show that predicting species’ responses to climate change often require physiological information to understand climatic range determinants, and a metapopulation model that can make full use of this data to more realistically account for processes such as local extirpation, demographic rescue, source-sink dynamics and dispersal-limitation. This article is protected by copyright. All rights reserved.

Description: Abstract The influence of different drivers on changes in North American and European boreal forests biomass burning (BB) during the Holocene was investigated based on the following hypotheses: land use was important only in the southernmost regions, while elsewhere climate was the main driver modulated by changes in fuel type. BB was reconstructed by means of 88 sedimentary charcoal records divided into six different site clusters. A statistical approach was used to explore the relative contribution of (a) pollen‐based mean July/summer temperature and mean annual precipitation reconstructions, (b) an independent model‐based scenario of past land use (LU), and (c) pollen‐based reconstructions of plant functional types (PFTs) on BB. Our hypotheses were tested with: (a) a west‐east northern boreal sector with changing climatic conditions and a homogeneous vegetation, and (b) a north‐south European boreal sector characterized by gradual variation in both climate and vegetation composition. The processes driving BB in boreal forests varied from one region to another during the Holocene. However, general trends in boreal biomass burning were primarily controlled by changes in climate (mean annual precipitation in Alaska, northern Quebec, and northern Fennoscandia, and mean July/summer temperature in central Canada and central Fennoscandia) and, secondarily, by fuel composition (BB positively correlated with the presence of boreal needleleaf evergreen trees in Alaska and in central and southern Fennoscandia). Land use played only a marginal role. A modification towards less flammable tree species (by promoting deciduous stands over fire‐prone conifers) could contribute to reduce circumboreal wildfire risk in future warmer periods.

Description: Abstract Most assessments of the effectiveness of river restoration are done at small spatial scales (〈10 km) over short time frames (less than three years), potentially failing to capture large‐scale mechanisms such as completion of life‐history processes, changes to system productivity, or time lags of ecosystem responses. To test the hypothesis that populations of two species of large‐bodied, piscivorous, native fishes would increase in response to large‐scale structural habitat restoration (reintroduction of 4,450 pieces of coarse woody habitat into a 110‐km reach of the Murray River, southeastern Australia), we collected annual catch, effort, length, and tagging data over seven years for Murray cod (Maccullochella peelii) and golden perch (Macquaria ambigua) in a restored “intervention” reach and three neighboring “control” reaches. We supplemented mark–recapture data with telemetry and angler phone‐in data to assess the potentially confounding influences of movement among sampled populations, heterogeneous detection rates, and population vital rates. We applied a Bayesian hierarchical model to estimate changes in population parameters including immigration, emigration, and mortality rates. For Murray cod, we observed a threefold increase in abundance in the population within the intervention reach, while populations declined or fluctuated within the control reaches. Golden perch densities also increased twofold in the intervention reach. Our results indicate that restoring habitat heterogeneity by adding coarse woody habitats can increase the abundance of fish at a population scale in a large, lowland river. Successful restoration of poor‐quality “sink” habitats for target species relies on connectivity with high‐quality “source” habitats. We recommend that the analysis of restoration success across appropriately large spatial and temporal scales can help identify mechanisms and success rates of other restoration strategies such as restoring fish passage or delivering water for environmental outcomes.

Description: An essential ecosystem service is the dilution effect of biodiversity on disease severity, yet we do not fully understand how this relationship might change with continued climate warming and ecosystem degradation. We designed removal experiments in natural assemblages of Tibetan alpine meadow vegetation by manipulating plot-level plant diversity to investigate the relationship between different plant biodiversity indices and foliar fungal pathogen infection, and how artificial fertilization and warming affect this relationship. Although pathogen group diversity increases with host species richness, disease severity decreases as host diversity rises (dilution effect). The dilution effect of phylogenetic diversity on disease held across different levels of host species richness (and equal abundances), meaning that the effect arises mainly in association with enhanced diversity itself rather than from shifting abundances. However, the dilution effect was weakened by fertilization. Among indices, phylogenetic diversity was the most parsimonious predictor of infection severity. Experimental warming and fertilization shifted the most supported predictor to species richness. Compared to planting experiments where artificial communities are constructed from scratch, our removal experiment in natural communities more realistically demonstrate that increasing perturbation adjusts natural community resistance to disease severity. This article is protected by copyright. All rights reserved.

Description: 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F203, NSC 703786) lysylamide belongs to a novel mechanistic class of antitumor agents. It elicits activity against ovarian, breast, kidney and colorectal cancer models. In sensitive breast cancer cells, 5F203 activates aryl hydrocarbon receptor (AhR) signaling. Herein, we evaluate the role of AhR in 5F203 activity in two ovarian cancer cell lines: IGROV-1 (sensitive to 5F203), SKOV-3 (resistant to this agent). In addition, cancer cells have been isolated from ascites fluid of ovarian cancer patients; sensitivity to 5F203 and concurrent AhR signal transduction has been examined in ascites-isolated ovarian cancer patients' cells. 5F203 induced enhanced CYP1A1 expression, AhR translocation and ROS formation in IGROV-1 cells and ascites-isolated ovarian cancer cells that were sensitive to 5F203. In IGROV-1 cells 5F203-induced ROS formation was accompanied by JNK, ERK and P38MAPK phosphorylation, DNA damage and cell cycle arrest prior to apoptosis. In contrast, 5F203 failed to induce CYP1A1 expression, AhR translocation or oxidative stress in 5F203-resistant SKOV-3 cells, or in ovarian cancer ascites cells inherently resistant to this agent. We propose that AhR may represent a new molecular target in the treatment of ovarian tumors and 5F203 may exemplify a potential novel treatment. Furthermore, putative biomarkers of sensitivity to this agent have been identified. J. Cell. Biochem. © 2013 Wiley Periodicals, Inc.

Description: Questions Within a metacommunity, what determines how local species composition differs from the regional community? How do local conditions and landscape context affect this differentiation in wetland vegetation? Location Fleurieu Peninsula, South Australia. Methods We sampled native vegetation across 26 hydrological gradients in a wetland metacommunity within a heavily cleared agricultural landscape. We used the local contribution to beta diversity to quantify how species composition at each site differed from the average across all sites. We hypothesised that local contribution to beta diversity would respond to assembly processes (niche, biological interactions, dispersal) through effects on the species-turnover- and richness-difference components of beta diversity. We used beta regression to model local contribution to beta diversity, building a candidate set of 55 models, each incorporating one of the assembly processes. We used standardised regression coefficients to measure effect size, and null models to explore diversity patterns further. Results While variation in among-site niche dimensions were influential, the strongest control on local contribution to beta diversity was a negative association with the number of wetlands within 200 m. Null models showed this was because common species were over-represented in well-connected sites within the metacommunity, while rare species were under-represented. Conclusions Our results demonstrate the homogenisation of native plant species composition in well-connected wetlands, consistent with theoretical predictions of declining beta diversity when connectivity is high. We recommend comparative analysis of local species composition to regional average diversity to evaluate the role of wetland connectivity in homogenisation of composition before conservation or restoration priorities are assigned. This article is protected by copyright. All rights reserved.

Description: We investigated activity and mechanism of action of two AhR ligand antitumor agents, AFP 464 and 5F 203 on human renal cancer cells, specifically examining their effects on cell cycle progression, apoptosis and migration. TK-10, SN12C, Caki-1 and ACHN human renal cancer cell lines were treated with AFP 464 and 5F 203. We evaluated cytotoxicity by MTS assays, cell cycle arrest and apoptosis by flow cytometry and corroborated a mechanism of action involving AhR signal transduction activation. Changes in migration properties by wound healing assays were investigated: 5F 203-sensitive cells show decreased migration after treatment, therefore we measured c-Met phosphorylation by Western blot in these cells. 5F 203 induced a decrease in cell viability which was more marked than AFP 464. This cytotoxicity was reduced after treatment with the AhR inhibitor Î ± -NF for both compounds indicating AhR signaling activation plays a role in the mechanism of action. 5F 203 is sequestered by TK-10 cells and induces CYP1A1 expression; 5F 203 potently inhibited migration of TK-10, Caki-1 and SN12C cells, and inhibited c-Met receptor phosphorylation in TK-10 cells. AhR ligand antitumor agents AFP 464 and 5F 203 represent potential new candidates for the treatment of renal cancer. 5F 203 only inhibited migration of sensitive cells and c-Met receptor phosphorylation in TK-10 cells. c-Met receptor signal transduction is important in migration and metastasis. Therefore, we consider that 5F 203 offers potential for the treatment of metastatic renal carcinoma. This article is protected by copyright. All rights reserved

Description: When isolated mitochondria from the yeast Saccharomyces cerevisiae oxidize respiratory substrates in the absence of phosphate and ADP, the yeast mitochondrial unselective channel, also called the yeast permeability transition pore (yPTP), opens in the inner membrane dissipating the electrochemical gradient. ATP also induces yPTP opening. yPTP opening allows mannitol transport into isolated mitochondria of laboratory yeast strains, but mannitol is not readily permeable through the yPTP in an industrial yeast strain, Yeast Foam. The presence of oligomycin, an inhibitor of ATP synthase, allowed for respiration-induced mannitol permeability in mitochondria from this strain. Potassium (K + ) had varied effects on the respiration-induced yPTP depending on the concentration of the respiratory substrate added. At low respiratory substrate concentrations K + inhibited respiration-induced yPTP opening, while at high substrate concentrations this effect diminished. However, at the high respiratory substrate concentrations, the presence of K + partially prevented phosphate inhibition of yPTP opening. Phosphate was found to inhibit respiration-induced yPTP opening by binding a site on the matrix space side of the inner membrane in addition to its known inhibitory effect of donating protons to the matrix space to prevent the pH change necessary for yPTP opening. The respiration-induced yPTP was also inhibited by NAD, Mg 2+ , NH 4 + , or the oxyanion vanadate polymerized to decavanadate. The results demonstrate similar effectors of the respiration-induced yPTP as those previously described for the ATP-induced yPTP and reconcile previous strain-dependent differences in yPTP solute selectivity. This article is protected by copyright. All rights reserved.

Description: The Vulnerable (IUCN) whale shark spans warm and temperate waters around the globe. However, their present-day and possible future global distribution has never been predicted. Using 30 years (1980-2010) of whale shark observations recorded by tuna purse-seiners fishing in the Atlantic, Indian and Pacific Oceans, we applied generalized linear mixed-effects models to test the hypothesis that similar environmental covariates predict whale shark occurrence in all major ocean basins. We derived global predictors from satellite images for chlorophyll a and sea surface temperature, and bathymetric charts for depth, bottom slope and distance to shore. We randomly generated pseudo-absences within the area covered by the fisheries, and included fishing effort as an offset to account for potential sampling bias. We predicted sea surface temperatures for 2070 using an ensemble of five global circulation models under a no climate-policy reference scenario, and used these to predict changes in distribution. The full model (excluding standard deviation of sea surface temperature) had the highest relative statistical support ( w AIC c = 0.99) and explained ~ 60% of the deviance. Habitat suitability was mainly driven by spatial variation in bathymetry and sea surface temperature among oceans, although these effects differed slightly among oceans. Predicted changes in sea surface temperature resulted in a slight shift of suitable habitat towards the poles in both the Atlantic and Indian Oceans (~ 5 ºN and 3‒8 ºS, respectively) accompanied by an overall range contraction (2.5‒7.4% and 1.1‒6.3%, respectively). Predicted changes in the Pacific Ocean were small. Assuming that whale shark environmental requirements and human disturbances (i.e., no stabilization of greenhouse gas emissions) remain similar, we show that warming sea surface temperatures might promote a net retreat from current aggregation areas and an overall redistribution of the species. This article is protected by copyright. All rights reserved.

Description: Questions Can the model performance of the landscape reconstruction algorithm (LRA) for small forest hollows be validated through comparison to inventory-based vegetation reconstructions from the last 150 yrs? Does the application of LRA and the comparison to historical data enhance interpretation of the pollen record? Location Denmark. The Gribskov-Ostrup small forest hollow (56°N, 12°20′ E, 44 m a.s.l.) in the forest of Gribskov, eastern Denmark. Methods Pollen analysis was carried out on a small forest hollow, and LRA used to derive pollen-based quantitative estimates of past vegetation. Historical forest inventory data and maps were used to reconstruct the vegetation within three different circles around the hollow (20, 50 and 200 m ring widths) for five time periods during the last 150 yrs. The results of the two approaches were compared in order to evaluate model performance, and the LRA-based reconstruction used to describe how the model changes interpretation of vegetation development during the last ca. 6500 yrs compared to the use of pollen percentages alone. Results Distance-weighted inventory-based reconstructions within 200 m of the hollow's edge provide the best match with the LRA-modelled vegetation. Precise validation of the model is not possible due to insufficient historical data, but the comparison indicates that the LRA reconstruction for Gribskov tends to (1) underestimate tree cover and overestimate open areas, (2) give a too high representation of on-site pollen types, (3) give an underestimation of Fagus and (4) a small overestimation of Quercus and Corylus . Despite these uncertainties, application of the LRA model shows a higher degree of openness than would be apparent from the uncorrected pollen diagram, and makes it possible to attempt to distinguish changes at the local scale from regional vegetation changes, thus giving a clearer picture of the vegetation changes at the site. Conclusions We demonstrate that the estimates of the LRA model applied to pollen data from small forest hollows can be compared with small-scale historical data to evaluate model performance. Landscape Reconstruction Algorithm-modelled vegetation showed the best match with distance-weighted inventory-based vegetation within a 200 m circle around the small hollow. Applying the model further back in time allowed reconstruction of local vegetation dynamics which are not detectable at the regional scale, such as a very early local occurrence of Fagus sylvatica around the site.