Comments on Brodie and Post: Climate-driven declines in wolverine populations: causal connection or spurious correlation?

The recent paper by Brodie and Post (“Nonlinear responses of wolverine populations to declining winter snowpack”, Popul Ecol 52:279–287, 2010) reports conclusions that are unsupportable, in our opinion, due to both mis-interpretations of current knowledge regarding the wolverine’s (Gulo gulo) association with snow, and the uncritical use of harvest data to index wolverine populations. The authors argue that, because the wolverine is a snow-dependent species, average annual provincial snowfall, based on weather station data, can be expected to correlate strongly and positively with wolverine population numbers, which in turn can be accurately indexed by trapper harvests. Thus, correlations between declines in wolverine harvests and declining average snowpack are interpreted to reflect a climate-driven decrease in wolverine populations. This conclusion overstates the nature of the wolverine’s association with snow, and makes unsupportable assumptions about the reliability of harvest data as a proxy for population size.     

Nonlinear responses of wolverine populations to declining winter snowpack

Understanding the population-level impacts of climate change is critical for effectively managing ecosystems. Predators are important components of many systems because they provide top−down control of community structure. Ecological theory suggests that these species could be particularly susceptible to climate change because they generally occur at low densities and have resource-limited populations. Yet, our understanding of climate-change impacts on predators is hindered by the difficulty in assessing complex, nonlinear dynamics over the large spatial scales necessary to depict a species’ general response to abiotic forcing. Here we use fur-return data to characterize population dynamics of a snow-adapted carnivore, the wolverine, across most of its North American range. Using novel modeling techniques, we simultaneously measured the impact of winter snowpack on wolverine dynamics across critical thresholds in snowpack depth and two domains of population growth. Winter snowpack declined from 1970 to 2004 in nearly the entire region studied, concordant with increases in Northern Hemisphere temperature anomalies. Fur returns have declined in many areas; our models show that snowpack has strong, nonlinear effects on wolverine population dynamics. Importantly, wolverine harvests dropped the fastest in areas where snowpack declined most rapidly and also where snowpack had the greatest effect on population dynamics. Moreover, declining snow cover appears to drive trends in wolverine population synchrony, with important implications for overall persistence. These results illustrate the vulnerability and complex responses of predator populations to climate change. We also suggest that declining snowpack may be an important and hitherto little-analyzed mechanism through which climate change alters high-latitude ecosystems.     

Historical records of passerine introductions to New Zealand fail to support the propagule pressure hypothesis

Blackburn et al. (Biodiver Conserv 20:2189–2199, 2011) claim that a reanalysis of passerine introductions to New Zealand supports the propagule pressure hypothesis. The conclusions of Blackburn et al. (2011) are invalid for three reasons: First, the historical record is so flawed that there is no sound basis for identifying the mechanisms behind extinction following introduction, or whether species were successful because they were introduced in large numbers or were introduced in large numbers because earlier releases succeeded. Second, the GLIMMIX analysis of Blackburn et al. (2011) is biased in favor of the propagule pressure hypothesis. Third, the population viability analysis presented by Blackburn et al. (2011) is based on unjustified and questionable assumptions. It is likely that the outcome of passerine bird introductions to New Zealand depended on species characteristics, site characteristics, and human decisions more than on a simple summing of the numbers introduced.     

Incorporating Cold-Air Pooling into Downscaled Climate Models Increases Potential Refugia for Snow-Dependent Species within the Sierra Nevada Ecoregion,CA

We present a unique water-balance approach for modeling snowpack under historic, current and future climates throughout the Sierra Nevada Ecoregion. Our methodology uses a finer scale (270 m) than previous regional studies and incorporates cold-air pooling, an atmospheric process that sustains cooler temperatures in topographic depressions thereby mitigating snowmelt. Our results are intended to support management and conservation of snow-dependent species, which requires characterization of suitable habitat under current and future climates. We use the wolverine (Gulo gulo) as an example species and investigate potential habitat based on the depth and extent of spring snowpack within four National Park units with proposed wolverine reintroduction programs. Our estimates of change in spring snowpack conditions under current and future climates are consistent with recent studies that generally predict declining snowpack. However, model development at a finer scale and incorporation of cold-air pooling increased the persistence of April 1^st snowpack. More specifically, incorporation of cold-air pooling into future climate projections increased April 1^st snowpack by 6.5% when spatially averaged over the study region and the trajectory of declining April 1^st snowpack reverses at mid-elevations where snow pack losses are mitigated by topographic shading and cold-air pooling. Under future climates with sustained or increased precipitation, our results indicate a high likelihood for the persistence of late spring snowpack at elevations above approximately 2,800 m and identify potential climate refugia sites for snow-dependent species at mid-elevations, where significant topographic shading and cold-air pooling potential exist.     

On the Theory of Evolution Versus the Concept of Evolution: Three Observations

Here we address three misconceptions stated by Rice et al. in their observations of our article Paz-y-Mi?o and Espinosa (Evo Edu Outreach 2:655–675, 2009), published in this journal. The five authors titled their note “The Theory of Evolution is Not an Explanation for the Origin of Life.” First, we argue that it is fallacious to believe that because the formulation of the theory of evolution, as conceived in the 1800s, did not include an explanation for the origin of life, nor of the universe, the concept of evolution would not allow us to hypothesize the possible beginnings of life and its connections to the cosmos. Not only Stanley Miller’s experiments of 1953 led scientists to envision a continuum from the inorganic world to the origin and diversification of life, but also Darwin’s own writings of 1871. Second, to dismiss the notion of Rice et al. that evolution does not provide explanations concerning the universe or the cosmos, we identify compelling scientific discussions on the topics: Zaikowski et al. (Evo Edu Outreach 1:65–73, 2008), Krauss (Evo Edu Outreach 3:193–197, 2010), Peretó et al. (Orig Life Evol Biosph 39:395–406, 2009) and Follmann and Brownson (Naturwissenschaften 96:1265–1292, 2009). Third, although we acknowledge that the term Darwinism may not be inclusive of all new discoveries in evolution, and also that creationists and Intelligent Designers hijack the term to portray evolution as ideology, we demonstrate that there is no statistical evidence suggesting that the word Darwinism interferes with public acceptance of evolution, nor does the inclusion of the origin of life or the universe within the concept of evolution. We examine the epistemological and empirical distinction between the theory of evolution and the concept of evolution and conclude that, although the distinction is important, it should not compromise scientific logic.     

Habitat,Climate, and Fisher and Marten Distributions

Since the mid-twentieth century, fisher populations (Pekania pennanti) increased in several eastern jurisdictions of North America, particularly in the northern part of the species’ range. Changes in fisher distribution have led to increased overlap with the southern portion of the range of American marten (Martes americana), whose populations may be locally declining. This overlap occurs particularly in habitats undergoing natural and anthropogenic modification. The objective of our study was to determine the respective effects of habitat changes and climatic conditions on fisher and marten populations in Quebec, Canada, based on trapper knowledge. We analyzed annual fisher and marten harvest (number of pelts sold/100 km²) between the 1984–1985 and 2014–2015 trapping seasons using linear mixed models. Fisher harvest increased with the increased abundance of mixed forests >12 m tall, resulting from decades of forest harvesting. Fisher harvest decreased with increasing spring rains, which can affect survival when rearing young. Marten harvest decreased with increasing winter rains, which lower thermoregulation capacity and hamper movements by creating an ice crust on the snowpack, reducing access to subnivean areas. Decline in marten harvest during the 30-year study period coincided with an increase in fisher harvest, suggesting possible interspecific competition. Results highlight that managers should strive to maintain mixedwood stands taller than 12 m to maintain high quality habitat for fishers. Our study confirms the importance of working with trappers to assess furbearing population trends in response to habitat changes and climatic conditions. © 2019 The Wildlife Society.     

Raccoon Pelt Price and Trapper Harvest Relationships Are Temporally Inconsistent

Trapping data have a long and rich history of use in monitoring furbearer populations in North America but understanding the influences of variation in trapper harvest is important. Many factors besides abundance can cause variation in trapper harvest, including socioeconomics, weather, and motivation. The relationships between these extrinsic factors and trapper harvest may change temporally, which may obscure the causal understanding of variation in trapper harvest. We tested for changes in the relationships between pelt price and trapper numbers, and pelt price and harvest per trapper for raccoons (Procyon lotor) in Illinois, USA, from 1976–2018 while controlling for other socioeconomic (gasoline price, unemployment) and weather (temp, snow depth) factors. The annual raccoon harvest showed no clear trend, whereas the number of raccoon trappers declined markedly from approximately 1976–1990 in conjunction with pelt prices, after which the number of trappers remained relatively stable and were not significantly affected by pelt price. In contrast, harvest per trapper increased markedly during the 1990s and showed a significant negative relationship with pelt price pre-1990 but a positive relationship post-1990. We propose that declines in pelt prices resulted in a loss of less experienced or economically incentivized trappers, whereas contemporary trappers may continue trapping primarily for non-economic reasons. Our study highlights the potential for using non-linear relationships between trapper harvest data and socioeconomic covariates to help understand the influences of temporal variation in trapper harvest data. © 2020 The Wildlife Society.     

Identifying and Controlling for Variation in Canid Harvest Data

An accurate understanding of harvest trends is required for effective wildlife management. Trapper harvest data represent valuable long-term data for evaluating patterns and trends for wildlife species at broad spatiotemporal scales. Inferring accurate trends from harvest data, however, first requires identifying and controlling for confounding factors that vary independent of abundance. We investigated trends in 43 years of trapper harvest data (1976–2018) from Illinois, USA, for red fox (Vulpes vulpes), gray fox (Urocyon cinereoargenteus), and coyote (Canis latrans) while controlling for factors that may affect trapper effort, including number of effective (i.e., successful) trappers, pelt price, gasoline price, winter unemployment, and winter weather conditions. Annual trapper harvest for red and gray foxes declined and was affected by gasoline price and winter unemployment, whereas annual trapper harvest for coyotes increased and was not strongly affected by other covariates. After adjusting for pelt price, harvest of red foxes was relatively stable, but harvest of gray foxes declined and harvest of coyotes increased. Effects of covariates on harvest per successful trapper varied by species; nevertheless, we detected an increasing trend for coyotes and decreasing trends for gray foxes and red foxes. Concordance across indices for gray foxes and coyotes was consistent with hypothesized declines for gray foxes and increases for coyotes in the midwestern United States. Trends for red foxes varied depending on how we accounted for potential confounding factors and it is unclear if these trends suggest population declines or distribution shifts to urban areas with reduced trapping susceptibility. Our results highlight the importance of understanding sources of variation in harvest data and that their effects can vary across species. © 2020 The Wildlife Society.     

Sub-equilibrium oxygen-18 and carbon-13 levels in biological carbonates: carbonate and kinetic models

Many biological carbonates contain less oxygen-18 and carbon-13 than expected for isotopic equilibrium with ambient waters. "Carbonate" explanations for the oxygen-18 deficiencies draw inspiration from McCrea's (1950) observation that dissolved inorganic carbonates (DIC), in isotopic equilibrium with water, lose oxygen-18 in proportion to the abundance of the carbonate ion. Spero et al. (1997) therefore suggested that high carbonate levels might cause foraminifera to produce isotopically lighter shells at elevated pH. Adkins et al. (2003) extended this idea to the (presumably) alkaline internal calcification sites of deep-sea corals, and related skeletal carbon-13 content to the use of molecular carbon dioxide in calcification. This review compares these "carbonate" ideas with an updated "kinetic" model, which attributes isotopic enlightenment (for carbon-13 and oxygen-18) to carbon-dioxide-based calcification, and incomplete isotopic equilibration between DIC and water.     

Conclusions from a dynamic population model for tsetse: response to comments

The critique by Hargrove et al. (Popul Ecol, 2011) of our recently published paper on a tsetse population model (Barclay and Vreysen in Popul Ecol 53:89–110, 2011) has made some good points but has also misinterpreted the intent of some of our results as we presented them. Hargrove et al. rightly say that there is a mismatch between the size of the unit cells in the model (1 ha) and the iteration rate of the model (every 5 days), yielding too low a dispersal rate to simulate reality. However, they have misconstrued several of our results that we presented as examples to imply that those results were a necessary condition for control of tsetse, especially using traps and targets.     

Assessing loss of coral cover on the Great Barrier Reef: A response to Hughes et al. (2011)

Hughes et al. (Coral Reefs, 2011, in press) challenge our interpretations of the changes in coral cover observed on the Great Barrier Reef (GBR) between 1986 and 2004 (Sweatman et al. in Coral Reefs 30:521–531, 2011). They question whether we can accurately assign all causes of coral loss; we contend that this makes no difference to the observed changes. They defend the validity of historical data on coral cover from before the start of systematic large-scale monitoring and conclude that coral cover has been declining since at least 1960, but we find no trend in the early data. We remain convinced that combining data collected at different spatial scales (quadrats and transects in the past mixed with more recent whole-reef averages from manta tows) are likely to overestimate decline, because whole-reef averages will very rarely reach the high cover values that can occur at the quadrat scale. Hughes et al. (Coral Reefs, 2011, in press) state that we dismiss runoff as a cause of ecosystem degradation; we defend our interpretations and dispute some of their examples. In summary, we stand by our conclusion that coral cover on the GBR declined in the period 1986–2004 but through localised and unsynchronised changes that included recovery.     

100% complete assignment of non-labile 1H, 13C, and 15N signals for calcium-loaded calbindin D9k P43G

Here we present the 100% complete assignment chemical shift of non-labile ¹H, ¹⁵N and ¹³C nuclei of Calbindin D_9k P43G. The assignment includes all non-exchangeable side chain nuclei, including ones that are rarely reported, such as LysNζ as well as the termini. NMR experiments required to achieve truly complete assignments are discussed. To the best of our knowledge our assignments for Calbindin D_9k extend beyond previous studies reaching near-completeness (Vis et al. in Biochem 33:14858–14870, 1994; Yamazaki et al. in J Am Chem Soc 116:6464–6465, 1994; Yamazaki et al. in Biochem 32:5656–5669, 1993b).     

A response to information criterion-based clustering with order-restricted candidate profiles in short time-course microarray experiments

Background  

For gene expression data obtained from a time-course microarray experiment, Liu et al. [1] developed a new algorithm for clustering genes with similar expression profiles over time. Performance of their proposal was compared with three other methods including the order-restricted inference based methodology of Peddada et al. [2, 3]. In this note we point out several inaccuracies in Liu et al. [1] and conclude that the order-restricted inference based methodology of Peddada et al. (programmed in the software ORIOGEN) indeed operates at the desired nominal Type 1 error level, an important feature of a statistical decision rule, while being computationally substantially faster than indicated by Liu et al. [1].     

Estimating Sustainable Harvest in Wolverine Populations Using Logistic Regression

Abstract: Population viability analysis (PVA) is a common tool to evaluate population vulnerability. However, most techniques require reliable estimates of underlying population parameters, which are often difficult to obtain and PVA are, therefore, best used in a qualitative context. Logistic regression is a powerful alternative to traditional PVA methods but has received surprisingly limited attention. Logistic regression fits regression equations to binary output from PVA models at a specific point in time to predict probability of a binary response over a range of parameter values. We used logistic regression on output from stochastic population models to evaluate the relative importance of demographic parameters for wolverine (Gulo gulo) populations and to estimate sustainable harvest in a wolverine population in Alaska. Our analysis indicated that adult survival is the most important demographic parameter to reliably estimate in wolverine populations because it had a greater effect on population persistence than did both fecundity and subadult survival. In accordance with this, harvest rate had a greater effect on population persistence than did any of the other harvest- and migration-related variables we tested. Furthermore, a high proportion of harvested females strengthened the effect of harvest. Hypothetical wolverine populations suffered high probabilities of both extinction and population decline over a range of realistic population sizes and harvest regimes. We suggest that harvested wolverine populations must be regarded as sink populations and that source populations in combination with sufficient dispersal corridors must be secured for any wolverine harvest to be sustainable.     

Implications of considering metal bioavailability in estimates of freshwater ecotoxicity: examination of two case studies

Purpose  

Previous methods of estimating characterization factors (CFs) of metals in life cycle impact assessment (LCIA) models were based on multimedia fate, exposure, and effect models originally developed to address the potential impacts of organic chemicals. When applied to metals, the models neglect the influence of ambient chemistry on metal speciation, bioavailability and toxicity. Gandhi et al. (2010) presented a new method of calculating CFs for freshwater ecotoxicity that addresses these metal-specific issues. In this paper, we compared and assessed the consequences of using the new method versus currently available LCIA models for calculating freshwater ecotoxicity, as applied to two case studies previously examined by Gloria et al. (2006): (1) the production of copper (Cu) pipe and (2) a zinc (Zn) gutter system.     

Photocatalytic disinfection using titanium dioxide: spectrum and mechanism of antimicrobial activity

The photocatalytic properties of titanium dioxide are well known and have many applications including the removal of organic contaminants and production of self-cleaning glass. There is an increasing interest in the application of the photocatalytic properties of TiO₂ for disinfection of surfaces, air and water. Reviews of the applications of photocatalysis in disinfection (Gamage and Zhang 2010; Chong et al., Wat Res 44(10):2997–3027, 2010) and of modelling of TiO₂ action have recently been published (Dalrymple et al. , Appl Catal B 98(1–2):27–38, 2010). In this review, we give an overview of the effects of photoactivated TiO₂ on microorganisms. The activity has been shown to be capable of killing a wide range of Gram-negative and Gram-positive bacteria, filamentous and unicellular fungi, algae, protozoa, mammalian viruses and bacteriophage. Resting stages, particularly bacterial endospores, fungal spores and protozoan cysts, are generally more resistant than the vegetative forms, possibly due to the increased cell wall thickness. The killing mechanism involves degradation of the cell wall and cytoplasmic membrane due to the production of reactive oxygen species such as hydroxyl radicals and hydrogen peroxide. This initially leads to leakage of cellular contents then cell lysis and may be followed by complete mineralisation of the organism. Killing is most efficient when there is close contact between the organisms and the TiO₂ catalyst. The killing activity is enhanced by the presence of other antimicrobial agents such as Cu and Ag.     

Plant-food and tool transfer among savanna chimpanzees at Fongoli, Senegal

Transferring food is considered a defining characteristic of humans, as such behavior is relatively uncommon in other animal species save for kin-based transfer. Chimpanzees (Pan troglodytes) are one exception, as they commonly transfer meat among nonrelatives but rarely transfer other resources. New observations at Fongoli, Senegal, show habitual transfer of wild-plant foods and other non-meat resources among community members beyond transfers from mother to offspring. We explore various explanations for these behaviors with a focus on age- and sex-class patterns in transfer events. In a total of 27 of 41 cases, male chimpanzees at Fongoli transferred wild-plant foods or tools to females. Most other cases involved transfer among males or males taking food from females. In light of male–female transfer patterns at Fongoli, we examine four hypotheses that have been applied to food transfer in apes: (1) testing for male-coercive tendency (van Noordwijk and van Schaik, Behav Ecol Sociobiol 63:883–890, 2009), (2) costly signaling (Hockings et al. PLoS ONE 2:e886, 2007), (3) food-for-sex (Gomes and Boesch, PLoS ONE 4:5116, 2009), and (4) sharing-under-pressure (Gilby, Anim Behav 71:953–963, 2006). We also consider hypotheses posed to explain transfer among callitrichids, where such behavior is more common (Ruiz-Miranda et al. Am J Primatol 48:305–320, 1999). Finally, we examine variables such as patch and food size and food transport. We discuss our findings relative to general patterns of non-meat transfer in Pan and examine them in the context of chimpanzee sociality in particular. We then contrast chimpanzee species and subspecies in terms of non-meat food and tool transfer and address the possibility that a savanna environment contributes to the unusual pattern observed at Fongoli.     

ROS-Mediated ABA Signaling

In plants, reactive oxygen species (ROS) are short-lived molecules produced through various cellular mechanisms in response to biotic and abiotic stimuli. ROS function as second messengers for hormone signaling, development, oxygen deprivation, programmed cell death, and plant–pathogen interactions. Recent research on ROS-mediated responses has produced stimulating findings such as the specific sources of ROS production, molecular elements that work in ROS-mediated signaling and homeostasis, and a ROS-regulated gene network (Neill et al., Curr Opin Plant Biol 5:388–395, 2002a; Apel and Hirt, Annu Rev Plant Biol 55:373–399, 2004; Mittler et al., Trends Plant Sci 9:490–498, 2004; Mori and Schroeder, Plant Physiol 135:702–708, 2004; Kwak et al., Plant Physiol 141:323–329, 2006; Torres et al., Plant Physiol 141:373–378, 2006; Miller et al., Physiol Plant 133:481–489, 2008). In this review, we highlight new discoveries in ROS-mediated abscisic acid (ABA) signaling. Drs. Daeshik Cho and June M. Kwak are the corresponding authors for this paper.