Effect of Small‐Scale Heterogeneity of Prey and Hunter Distributions on the Sustainability of Bushmeat Hunting

Abstract: Bushmeat is the main source of protein and the most important source of income for rural people in the Congo Basin, but intensive hunting of bushmeat species is also a major concern for conservationists. Although spatial heterogeneity in hunting effort and in prey populations at the landscape level plays a key role in the sustainability of hunted populations, the role of small‐scale heterogeneity within a village hunting territory in the sustainability of hunting has remained understudied. We built a spatially explicit multiagent model to capture the dynamics of a system in which hunters and preys interact within a village hunting territory. We examined the case of hunting of bay duikers (Cephalophus dorsalis) in the village of Ntsiété, northeastern Gabon. The impact of hunting on prey populations depended on the spatial heterogeneity of hunting and prey distribution at small scales within a hunting area. Within a village territory, the existence of areas hunted throughout the year, areas hunted only during certain seasons, and unhunted areas contributed to the sustainability of the system. Prey abundance and offtake per hunter were particularly sensitive to the frequency and length of hunting sessions and to the number of hunters sharing an area. Some biological parameters of the prey species, such as dispersal rate and territory size, determined their spatial distribution in a hunting area, which in turn influenced the sustainability of hunting. Detailed knowledge of species ecology and behavior, and of hunting practices are crucial to understanding the distribution of potential sinks and sources in space and time. Given the recognized failure of simple biological models to assess maximum sustainable yields, multiagent models provide an innovative path toward new approaches for the assessment of hunting sustainability, provided further research is conducted to increase knowledge of prey species’ and hunter behavior.     

Authentic leadership as a pathway to positive health

We propose to bridge the domains of positive health and leadership. We suggest that a “positive” health model helps explain highly effective leadership. The leader must strive for health and facilitate health in his/her followers. We look at leadership through this new and positive lens, that of “positive” health promotion. Copyright © 2008 John Wiley & Sons, Ltd.     

A method to estimate pre-exploitation population size

Antarctic fur seals (Arctocephalus gazella) were commercially exploited on the subantarctic island of South Georgia for over 100 years and nearly driven to extinction. Since the cessation of harvesting, however, their populations have rebounded, and they are now often considered a nuisance species whose impact on the terrestrial landscape should be mitigated. Any evaluation of their current population requires the context provided by their historic, pre-exploitation abundance, lest ecologists fall prey to shifting baseline syndrome in which their perspective on current abundance is compared only with an altered state resulting from past anthropogenic disturbance. Estimating pre-exploitation abundance is critical to defining species recovery and setting recovery targets, both of which are needed for the International Union for the Conservation of Nature's recent efforts to develop a green list of recovering species. To address this issue, we reconstructed the South Georgia fur seal harvest from 1786 to 1908 from ship logbooks and other historical records and interpolated missing harvest data as necessary with a generalized linear model fit to the historical record. Using an approximate Bayesian computation framework, harvest data, and a stochastic age-structured population model, we estimated the pre-exploitation abundance of Antarctic fur seals on South Georgia was 2.5 million females (95% CI 1.5–3.5 million). This estimate is similar to recent abundance estimates, and suggests current populations, and the ecological consequences of so many fur seals on the island, may be similar to conditions prior to human harvest. Although the historic archive on the fur sealing era is unavoidably patchy, the use of archival records is essential for reconstructing the past and, correspondingly, to understanding the present. Article impact statement: Defining species recovery requires an understanding of baseline population state, which can be estimated through statistical methods.     

Invasion costs,impacts, and human agency: response to Sagoff 2020

Article impact statement: In an era of profound biodiversity crisis, invasion costs, invader impacts, and human agency should not be dismissed.     

Assessing the extent and nature of wildlife trade on the dark web

Use of the internet as a trade platform has resulted in a shift in the illegal wildlife trade. Increased scrutiny of illegal wildlife trade has led to concerns that online trade of wildlife will move onto the dark web. To provide a baseline of illegal wildlife trade on the dark web, we downloaded and archived 9852 items (individual posts) from the dark web, then searched these based on a list of 121 keywords associated with illegal online wildlife trade, including 30 keywords associated with illegally traded elephant ivory on the surface web. Results were compared with items known to be illegally traded on the dark web, specifically cannabis, cocaine, and heroin, to compare the extent of the trade. Of these 121 keywords, 4 resulted in hits, of which only one was potentially linked to illegal wildlife trade. This sole case was the sale and discussion of Echinopsis pachanoi (San Pedro cactus), which has hallucinogenic properties. This negligible level of activity related to the illegal trade of wildlife on the dark web relative to the open and increasing trade on the surface web may indicate a lack of successful enforcement against illegal wildlife trade on the surface web.     

Hybridization,agency discretion,and implementation of the U.S. Endangered Species Act

The U.S. Endangered Species Act (ESA) requires that the “best available scientific and commercial data” be used to protect imperiled species from extinction and preserve biodiversity. However, it does not provide specific guidance on how to apply this mandate. Scientific data can be uncertain and controversial, particularly regarding species delineation and hybridization issues. The U.S. Fish and Wildlife Service (FWS) had an evolving hybrid policy to guide protection decisions for individuals of hybrid origin. Currently, this policy is in limbo because it resulted in several controversial conservation decisions in the past. Biologists from FWS must interpret and apply the best available science to their recommendations and likely use considerable discretion in making recommendations for what species to list, how to define those species, and how to recover them. We used semistructured interviews to collect data on FWS biologists’ use of discretion to make recommendations for listed species with hybridization issues. These biologists had a large amount of discretion to determine the best available science and how to interpret it but generally deferred to the scientific consensus on the taxonomic status of an organism. Respondents viewed hybridization primarily as a problem in the context of the ESA, although biologists who had experience with hybridization issues were more likely to describe it in more nuanced terms. Many interviewees expressed a desire to continue the current case‐by‐case approach for handling hybridization issues, but some wanted more guidance on procedures (i.e., a “flexible” hybrid policy). Field‐level information can provide critical insight into which policies are working (or not working) and why. The FWS biologists’ we interviewed had a high level of discretion, which greatly influenced ESA implementation, particularly in the context of hybridization.     

Alignment of threat,effort, and perceived success in North American conservation translocations

The use of conservation translocations to mitigate human effects on biodiversity is increasing, but how these efforts are allocated remains unclear. Based on a comprehensive literature review and online author survey, we sought to determine the goals of translocation efforts, whether they focus on species and regions with high threat and likelihood of perceived success, and how success might be improved. We systematically searched the ISI Web of Knowledge and Academic Search Complete databases to determine the species and regions of conservation translocations and found 1863 articles on conservation translocations in the United States, Canada, Mexico, Central America, and Caribbean published from 1974 to 2013. We questioned 330 relevant authors to determine the motivation for translocations, how translocations were evaluated, and obstacles encountered. Conservation translocations in North America were geographically widespread (in 21 countries), increased in frequency over time for all animal classes (from 1 in 1974 to 84 in 2013), and included 279 different species. Reintroductions and reinforcements were more common in the United States than in Canada and Mexico, Central America, or the Caribbean, and their prevalence was correlated with the number of species at risk at national and state or provincial levels. Translocated species had a higher threat status at state and provincial levels than globally (International Union for Conservation of Nature Red List categorization), suggesting that translocations may have been motivated by regional priorities rather than global risk. Our survey of authors was consistent with these results; most translocations were requested, supported, or funded by government agencies and downlisting species at national or state or provincial levels was the main goal. Nonetheless, downlisting was the least reported measure of success, whereas survival and reproduction of translocated individuals were the most reported. Reported barriers to success included biological factors such as animal mortality and nonbiological factors, such as financial constraints, which were less often considered in the selection of release sites. Our review thus highlights discrepancies between project goals and evaluation criteria and between risk factors considered and obstacles encountered, indicating room to further optimize translocation projects.     

Rates of nitrification,distribution of nitrifying bacteria,and nitrate fluxes in different types of sediment from Danish waters

Nitrification rates, measured in different sediment types from Danish waters, are in the range of 0.3 to 1.4 mmol NO ₃ ^- m^-2 d^-1. There is no signification between sandy and muddy sediments, nor between shallow and deeper stations. The extent of nitrification is probably limited to the zone of oxygen penetration, 1.5 to 5.5 mm. There are, however, nitrifying bacteria located in the anoxic sediment layers. There relative numbers were found by measuring the nitrification potential of the sediment. These potential rates (22°C) can also be used to calculate actual rates of nitrification, by adjusting to in situ temperature and oxygen penetration. These calculated rates agree with the actual measured rates of nitrification for a wide range of sediment types and may be used for the estimation of actual nitrification rates. Nitrate flux out from the sediment/water interface is in the range of 0 to 0.7 mmol NO ₃ ^- m^-2 d^-1. There is no correlation between concentration gradients of nitrate across the sediment/water interface and the measured flux of nitrate. Approximately 50% of nitrate production is released to the water column. The remainder (0 to 0.35 mmol N m^-2 d^-1) may have been denitrified.     

The polymorphism of the human serum paraoxonase †

The activity of paraoxonase, the enzyme which hydrolyses paraoxon, 0,0‐diethyl‐0–4‐nitrophenylphosphate, in human serum shows a genetically determined polymorphism with strong interethnic differences. The serum paraoxonase genotype has a significant influence on the paraoxon clearance. Individuals with high serum paraoxonase activity may be better protected against the toxic effects of parathion (0,0‐diethyl‐0–4‐nitrophenylthiophosphate).

In Caucasians the polymorphism is governed by two alleles. The first allele has a gene frequency p _low of 0.67 to 0.78, and is manifested in both the form of a first homozygotic group with low activities and a second heterozygotic group with medium activities. About 50% of all Europeans belong to the low activity group. The second allele with a gene frequency q _high of 0.22 to 0.33 is manifested in the second heterozygotic and a third homozygotic group with medium resp. high activities. The Hardy‐Weinberg rule for a two allele model is valid for the distribution.

The percentage of the low activity group decreases as one moves from Europe to Africa and Asia. In most of the Mongoloids and Negroids only 5 to 20% of the population can be included in the low activity group, which is not even demonstrable in Aborigines, Maoris, Tonga and some African and Indian (Central America) tribes. The validity of the Hardy‐Weinberg rule for a two‐ or three‐allele model must be rejected in non‐Caucasians.     

Patterns of serum calcium fractions,magnesium, phosphates and albumin in non‐insulin dependent diabetics (Nidd)

Blood level of calcium fractions (ionized and bound), phosphates, magnesium and albumin were measured in non‐insulin dependent diabetic patients (NIDD). Results were compared with healthy controls to elucidate the pathogenesis of probable changes of these elements. Total ionized calcium and magnesium showed significant decrease (p<0.001, p<0.05 and p<0.05) respectively. Phosphates showed non‐significant decrease while albumin reported nearly similar results. Positive correlation between inorganic phosphates and ionized calcium (r = 0.48, p<0.05) was observed only in healthy control group, not in diabetics. This may be attributed to alteration of ions excretions under diabetic condition through unknown mechanism. Additive increase of heparin sodium units in vitro to normal blood resulted in progressive fall in ionized calcium. Significant decrease was only observed upon addition of higher unit (5IU/ml). This must be taken into consideration biochemically for plasma determination of ionized calcium.