Unsustainable Loss Research Articles

Total response models as a conceptual management framework for conserving vulnerable secondary prey

AbstractMany of the world's native fauna suffer unsustainable losses from invasive mammalian predators. Conservation managers control predators on the premise that if large numbers are removed, prey will respond. This is sometimes true, but not always. Empirical relationships between predator densities and responses of vulnerable prey in Oceania often show little or no response across a broad range of predator reductions, with positive responses only at low threshold predator densities. Even then, some prey populations fail to respond. More research is required to identify predator thresholds across a range of prey taxa. This uncertainty of outcomes, coupled with the considerable cost of mammalian pest control, risks little or no return from limited conservation funds. A unifying theory is required to help understand why conservation outcomes from predator control are so variable despite the best efforts of conservation managers, and to expedite the right kind of management for a given prey species. We argue that a modern synthesis of numerical and functional response theory, in the form of total response models, provides such a theory. Stochastic consumer‐resource models are recommended for dynamic systems, but they are difficult to parameterize. Total response models, on the other hand, present a simple conceptual framework that managers can use as a heuristic to understand predator–prey systems, help explain some of the variability in predator control outcomes and stimulate thinking about other management options that can be integrated with predator control to improve conservation outcomes. Five rules of thumb are suggested to assist conservation managers.

Agricultural practices drive elevated rates of topsoil decline across Kenya, but terracing and reduced tillage can reverse this

As agricultural land area increases to feed an expanding global population, soil erosion will likely accelerate, generating unsustainable losses of soil and nutrients. This is critical for Kenya where cropland expansion and nutrient loading from runoff and erosion is contributing to eutrophication of freshwater ecosystems and desertification. We used the Revised Universal Soil Loss Equation (RUSLE) to predict soil erosion rates under present land cover and potential natural vegetation nationally across Kenya. Simulating natural vegetation conditions allows the degree to which erosion rates are elevated under current land use practices to be determined. This methodology exploits new digital soil maps and two vegetation cover maps to model topsoil (top 20 cm) erosion rates, lifespans (the mass of topsoil divided by erosion rate), and lateral nutrient fluxes (nutrient concentration times erosion rate) under both scenarios. We estimated the mean soil erosion rate under current land cover at ~5.5 t ha−1 yr−1, ~3 times the rate estimated for natural vegetation cover (~1.8 t ha−1 yr−1), and equivalent to ~320 Mt yr−1 of topsoil lost nationwide. Under present erosion rates, ~8.8 Mt, ~315 Kt, and ~ 110 Kt of soil organic carbon, nitrogen and phosphorous are lost from soil every year, respectively. Further, 5.3 % of topsoils (~3.1 Mha), including at >25 % of croplands, have short lifespans (<100 years). Additional scenarios were tested that assume combinations of terracing and reduced tillage practices were adopted on croplands to mitigate erosion. Establishing bench terraces with zoned tillage could reduce soil losses by ≥75 %; up to 87.1 t ha−1 yr−1. These reductions are comparable to converting croplands to natural vegetation, demonstrating most agricultural soils can be conserved successfully. Extensive long-term monitoring of croplands with terraces and reduced tillage established is required to verify the efficacy of these agricultural support practices as indicated by our modelling.

Ship-strike forecast and mitigation for whales in Gitga’at First Nation territory

As marine traffic increases globally, ship strikes have emerged as a primary threat to many baleen whale populations. Here we predict ship-strike rates for fin whalesBalaenoptera physalusand humpback whalesMegaptera novaeangliaein the central territorial waters of the Gitga’at First Nation (British Columbia, Canada), which face increases in existing marine traffic as well as new liquified natural gas (LNG) shipping in the next decade. To do so, we utilized Automatic Identification System (AIS) databases, line-transect surveys, shore-based monitoring, whale-borne tags, aerial drone-based focal follows, and iterative simulations. We predict that by 2030, whale encounters will triple for most vessel types, but the change is most extreme for large ships (length &gt;180 m) in prime whale habitat, in which co-occurrences will increase 30-fold. Ship-strike mortalities are projected to increase in the next decade by 2.3× for fin whales and 3.9× for humpback whales, to 2 and 18 deaths yr-1, respectively. These unsustainable losses will likely deplete both species in the coastal region of BC. Models indicate that the largest single source of mortality risk in 2030 will be from the LNG Canada project. Of the mitigation options we evaluated, a 10 knot speed ceiling for all large ships is potentially effective, but the best measure for guaranteed mitigation would be seasonal restrictions on LNG traffic. While certain data gaps remain, particularly with respect to humpback whales, our predictions indicate that shipping trends within Gitga’at waters will impact whale populations at regional levels. We provide our analysis in the R package ‘shipstrike’.

Fighting for Time: Rhodesia’s Military and Zimbabwe’s Independence by Charles D. Melson

<i>Fighting for Time: Rhodesia’s Military and Zimbabwe’s Independence</i> by Charles D. Melson

Rational Protein Engineering to Increase the Activity and Stability of IsPETase Using the PROSS Algorithm

Polyethylene terephthalate (PET) is the most widely used polyester plastic, with applications in the textile and packaging industry. Currently, re-moulding is the main path for PET recycling, but this eventually leads to an unsustainable loss of quality; thus, other means of recycling are required. Enzymatic hydrolysis offers the possibility of monomer formation under mild conditions and opens up alternative and infinite recycling paths. Here, IsPETase, derived from the bacterium Ideonella sakaiensis, is considered to be the most active enzyme for PET degradation under mild conditions, and although several studies have demonstrated improvements to both the stability and activity of this enzyme, stability at even moderate temperatures is still an issue. In the present study, we have used sequence and structure-based bioinformatic tools to identify mutations to increase the thermal stability of the enzyme so as to increase PET degradation activity during extended hydrolysis reactions. We found that amino acid substitution S136E showed significant increases to activity and stability. S136E is a previously unreported variant that led to a 3.3-fold increase in activity relative to wild type.

Protecting nests of the Critically Endangered South Pacific loggerhead turtle Caretta caretta from goanna Varanus spp. predation

AbstractThe South Pacific subpopulation of the loggerhead turtle Caretta caretta is categorized as Critically Endangered on the IUCN Red List because of significant population declines. Five Queensland beaches support high-density nesting of this subpopulation, but egg and hatchling survival are low at some beaches because of feral and native terrestrial predators. We quantified predation of loggerhead turtle eggs by two species of goanna, Varanus panoptes and Varanus varius, at Wreck Rock beach, one of the turtle's major nesting beaches. In addition, we conducted an experiment to determine the efficacy of a nest protection device. Predation rates at Wreck Rock beach were 15.2% for treatment and 45.8% for non-treatment clutches during the 2013–2014 nesting season. A higher probability of predation (64%) was predicted for the northern beach. Although nests were only partially predated (16.4% of the total number of eggs), nest loss to predators and beach erosion (caused by a cyclone) was 91.7%. If left unmanaged, the cumulative impact of predation and other threats, including those exacerbated by climate change, can cause unsustainable loss of loggerhead turtle nests. This study provides one of the first quantitative data sets on rates of loggerhead turtle clutch predation in the South Pacific. It enhances our understanding of goanna predation impacts and identifies an efficient predator exclusion device for mitigating the effects of terrestrial predators at Wreck Rock beach, and for protecting marine turtle nests across northern Australia and globally.

Who determines the trade-offs between agricultural production and environmental quality? An evolutionary perspective from rural eastern China

ABSTRACTWe explore the evolutionary nature of interactions between government policy, farm decision-making and ecosystem services in Shucheng County, Anhui Province, 1950–2015. Analyses of ecological, social and economic trends are complemented by interviews with local farmers. Since the Household Responsibility System started in 1980, there has been a trade-off between rising levels of provisioning services and falling levels of regulating services with evidence that critical thresholds have been passed for water quality. Using a Framework for Ecosystem Service Provision, we argue that farmers have acted only as ecosystem service providers and have not influenced the policies that have brought about the trade-offs. Over the period, ecological degradation is best described as an example of ‘creeping normalcy’ where cumulative conventional actions by individual farmers produce unsustainable losses in regulating services. The Chinese government should act to balance the various ecosystem services through valuation and national policy. In this respect, there is a need for agencies that can provide place-based advice to farmers that will allow them to maintain productivity levels while pursuing restorative actions. Even with new policies, the draw of urban employment, high production costs and an ageing population threaten the viability of farming in these marginal agricultural areas.

Nigerian briefing: how engineers can help secure a sustainable economy

Nigeria, the most populous country in Africa, has declining natural resources resulting in an unsustainable loss of personal inclusive wealth driven by exporting gas and crude oil for fuel, a landscape desiccated from the legacy of too many large dams, relentless population growth and culturally determined short-termism. Improving outcomes requires well-focused resources management and physical planning. These tasks require well-directed efforts from engineers informed by analysis of evidence of natural resources, human resources and manufacturing. This analysis, practised by economists developing Dasgupta's Inclusive Wealth Index concept, provides direction for achieving sustainability. Providing this direction is the nexus where the planning and management of Nigerian issues with energy (electricity), water (large dams) and land (agriculture) meet. These tasks require engineering inputs. Measures considered include adding value to mineral oil wealth by investment in petrochemicals production rather than exporting crude oil; management of natural water resources to realise the agricultural value of floodplains rather than wasteful water storage for failed irrigation projects; and success with generating and distributing electricity sufficient for economic activity in urban centres where half the people live. Engineers can provide better outcomes for Nigerian people, but there are some important culturally determined constraints to be addressed.

Gamma irradiation inactivates honey bee fungal, microsporidian, and viral pathogens and parasites.

Managed honey bee (Apis mellifera) populations are currently facing unsustainable losses due to a variety of factors. Colonies are challenged with brood pathogens, such as the fungal agent of chalkbrood disease, the microsporidian gut parasite Nosema spp., and several viruses. These pathogens may be transmitted horizontally from worker to worker, vertically from queen to egg and via vectors like the parasitic mite, Varroa destructor. Despite the fact that these pathogens are widespread and often harbored in wax comb that is reused from year to year and transferred across beekeeping operations, few, if any, universal treatments exist for their control. In order to mitigate some of these biological threats to honey bees and to allow for more sustainable reuse of equipment, investigations into techniques for the sterilization of hive equipment and comb are of particular significance. Here, we investigated the potential of gamma irradiation for inactivation of the fungal pathogen Ascosphaera apis, the microsporidian Nosema ceranae and three honey bee viruses (Deformed wing virus [DWV], Black queen cell virus [BQCV], and Chronic bee paralysis virus [CBPV]), focusing on the infectivity of these pathogens post-irradiation. Results indicate that gamma irradiation can effectively inactivate A. apis, N. ceranae, and DWV. Partial inactivation was noted for BQCV and CBPV, but this did not reduce effects on mortality at the tested, relatively high doses. These findings highlight the importance of studying infection rate and symptom development post-treatment and not simply rate or quantity detected. These findings suggest that gamma irradiation may function as a broad treatment to help mitigate colony losses and the spread of pathogens through the exchange of comb across colonies, but raises the question why some viruses appear to be unaffected. These results provide the basis for subsequent studies on benefits of irradiation of used comb for colony health and productivity.

Kepler’s Angels, Big and Small

Kepler’s Books, founded in 1955 in Menlo Park, CA, USA, was for many years an independent bookstore serving the Stanford University community. Its founder, Roy Kepler, a leftist with pacifist views, refused military service in World War II and later lobbied the US Congress about taxation and its military budget. The general trade bookstore was a nexus of left-wing and counter-culture voices, though it sold books from all parts of the political spectrum. Ownership of the bookstore passed, in the late 1980s, to Roy Kepler’s son Clark, and successful years followed, including selection as Bookseller of the Year by Publisher’s Weekly in 1990. But, with the rise of the bookstore chains (especially Borders and Barnes & Noble) and even more so with the advent of internet shopping and the emergence of Amazon.com as America’s biggest bookseller, Kepler’s, like many other independents, suffered unsustainable losses. A decision to close the store in 2005 provoked an uprising from the community. People complained about losing a beloved store where, ironically, most of them had stopped shopping some years before. Reopening the store required refinancing the business, this time under community ownership; the new business model brought on board Silicon Valley high-tech entrepreneurs who had never run a bookstore but who had marketing and management experience. A non-profit corporation, Peninsula Arts and Letters, was formed to run a literary events series, while the reconfigured bookstore remained a for-profit corporation, Clark Kepler eventually receding, via retirement, into the background. The success of the new business configuration raises questions about whether this business model is replicable for other similarly vulnerable independent bookstores in America, or whether the coincidental presence of high-income and highly educated people among Kepler’s neighbourhood clientele puts it in a special position hard to imitate elsewhere.

Managing Circulation Losses in a Harsh Drilling Environment: Conventional Solution vs. CHCD Through a Risk Assessment

Summary Conventional drilling techniques used in harsh drilling environments are sometimes impractical or uneconomical. This was experienced while drilling through the reservoir section being investigated. This section is characterized by high pressure and formation fluids estimated to contain 18–20% H2S and 4–6% CO2. The presence of extensive karst/fractures along with severe circulation losses prevents successful drilling using the conventional circulation technique. For this scenario, the pressurized-mud-cap closed-hole circulation-drilling (CHCD) technique was applied, and it proved to be the most effective method to drill through the Lower Carboniferous carbonate. In conventional drilling through such lost circulation zones, the typical method is to isolate the thief formation [lost circulation-materials (LCMs) pills, gunks, and cement plugs] to maintain an overbalanced condition. These methods have their disadvantages: uncertain results, time and cost increase, and damages on well productivity. Furthermore, it may be a long, ineffective process because of multiple leakoff zones or massively fractured zones. Where unsustainable losses occur and conventional circulation is no longer possible, the CHCD technique may be used to allow the continuation of drilling. This technique is not underbalanced drilling. The annulus is closed, and no returns are circulated to the surface. The CHCD is not a simple or an inexpensive system. It is used only when other systems for controlling losses have proved to be ineffective. Large quantities of water and mud are required as well as additional equipment and specialized personnel. An accurate evaluation of several factors has to be performed. Drilling hazards are the major issue because the primary barrier to well influx is jeopardized, but also rig time, material availability, and consumption have to be considered. The aforementioned uncertainties can be addressed through risk evaluations by comparing two drilling scenarios of a typical development well where one uses CHCD technology and the other uses conventional drilling techniques. This paper will discuss the operational details of conducting CHCD as well as the risk-management approach, which involves the identification, evaluation, and mapping of all risks involved in each scenario (qualitative risk assessment). A probabilistic model is, therefore, developed to combine all the risks identified and to address their consequences within operational time (quantitative risk assessment).

Managing Circulation Losses in a Harsh Drilling Environment

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 128225, ’Managing Circulation Losses in a Harsh Drilling Environment: Conventional Solution vs. CHCD Through a Risk Assessment,’ by S. Masi, C. Molaschi, SPE, and F. Zausa, Eni E&amp;P, and, J. Michelez, SPE, Altran, originally prepared for the 2010 IADC/SPE Drilling Conference and Exhibition, New Orleans, 2-4 February. The paper has not been peer reviewed. Conventional drilling techniques used in harsh drilling environments are sometimes impractical or uneconomical. This was experienced while drilling through the reservoir section being investigated. This section is characterized by high pressure and formation fluids estimated to contain 18 to 20% hydrogen sulfide (H2S) and 4 to 6% carbon dioxide (CO2). The presence of extensive karst/fractures along with severe circulation losses prevents successful drilling using conventional circulation techniques. For this scenario, the pressurized mud cap closed-hole-circulation drilling (CHCD) technique was used, and proved to be the most effective method to drill through the Lower Carboniferous carbonate. Introduction Drilling the reservoir section is the most challenging part of the drilling activity that is being carried out at the oil field under investigation. The reservoir is a carbonate platform, and it is well known that carbonate formations (limestone/dolomite) are characterized by the presence of fractures and/or large vugs, and consequently circulation losses frequently occur while drilling. Sometimes losses are minimal, but at other times they are sufficiently large to become total losses. This situation has been experienced often in this reservoir. In fact, in certain areas, unsustainable losses occur and conventional circulation is no longer possible. Therefore, one of the main concerns is the magnitude of losses that could be faced while drilling the reservoir zone. It must be emphasized that when using conventional drilling techniques through lost circulation zones, the standard practice is to minimize losses by attempting to seal off the thief zone before continuing drilling. This usually is done by pumping lost-circulation-materials (LCMs) pills and setting cement plugs so that the mud weight will overbalance formation pressure at all times. However, this is a long and often unsuccessful process because multiple leakoff zones may be encountered in sequence or because massively fractured zones cannot be cured. Furthermore, these methods have several disadvantages: they offer uncertain results, they are time consuming and therefore expensive, and in hydrocarbon reservoirs, they may reduce well productivity. In this scenario, the CHCD technique allows drilling in circulation-loss zones by controlling the annulus pressure and injecting a sacrificial fluid into the thief formations, thereby minimizing the nonproductive time and costs typically required to implement the traditional methods of circulation-loss control. For this field, CHCD was determined to be the most effective method to drill through the carbonate reservoir.

An Exploration of the Effect of Housing Unit Density on Aspects of Residential Landscape Sustainability in England

Residential landscapes are crucial to achieving sustainable housing. However, there are concerns that higher housing densities will lead to unsustainable loss of gardens, greenspace and tree cover. This paper explores the effect of housing density on these variables, and finds that only garden provision is negatively correlated. Total greenspace cover need not decrease with densification if flats are combined with communal spaces. However, the quality of these spaces and their sustainable credentials were seen to be highly variable. Tree cover provided by developers is not related to density—they appear to be reluctant to plant trees across the density range.

Rip &amp;#x2013; Mix &amp;#x2013; Burn: Why Content Repurposing Is the Answer to Digital Preservation

Traditional preservation arguments focused on two technological options, emulation [4, 5] and format conversion [1, 2, 3] or a combination of both [6]. All provide solutions to some preservation scenarios but also list limitations of scalability [3] and unsustainable loss [7], respectively, a common belief which led us to employ a procedural hybrid focused on access and usage, incorporating migration on access advantages described by LOCKSS [3].This strategy is based on the philosophy that any preservation action made directly to the original digital objects must be postponed until absolutely necessary, arguably forever. However, access is given immediately by employing current-era rendering programs and translating to current-era digital formats which are sufficiently-featured to fully represent the intellectual content in need of preservation. Therefore, we will argue that access, to mix and remix digital content, generates sufficient and necessary incentives [8, 15] to extend the life of digital objects, and indirectly that of digital formats, for as long as they are relevant to some user subgroup.Additionally, we will introduce assessment and measurement processes complementing the Rosenthal's LOCKSS model. We will develop the main argument by showing the relationships between the three distinct classes of costs incurred by any preservation program. We will show how INFORM methodology [10] is used to time the selection of new programs and formats. Lastly, we will show how translation loss can be measured, managed and validated, by employing a process built on the project at the Library of Congress to analyze the sustainability of digital formats [11].

Demography of a West African kob (Kobus kob kob) population

AbstractThe kob (Kobus kob kob) population studied in the Comoé National Park, Ivory Coast, suffered unsustainable losses to poaching before and during the investigation. This in turn did not only lead to low densities but also changed the population composition, resulting in a strong female bias in all age classes except juveniles. The relative rarity of adult males probably had negative effects on the population recruitment. Although mating occurred throughout the year and birth intervals were short, at least in some females, annual birth‐rate was low compared to earlier studies in the same area. Effective conservation measures are urgently needed to ensure the future existence of the studied population.