Evaluating the use of local ecological knowledge to monitor hunted tropicalforest wildlife over large spatial scales

Monitoring the distribution and abundance of hunted wildlife is critical to achieving sustainable resource use, yet adequate data are sparse for most tropical regions. Conventional methods for monitoring hunted forest-vertebrate species require intensive in situ survey effort, which severely constrains spatial and temporal replication. Integrating local ecological knowledge (LEK) into monitoring and management is appealing because it can be cost-effective, enhance community participation, and provide novel insights into sustainable resource use. We develop a technique to monitor population depletion of hunted forest wildlife in the Brazilian Amazon, based on the local ecological knowledge of rural hunters. We performed rapid interview surveys to estimate the landscape-scale depletion of ten large-bodied vertebrate species around 161 Amazonian riverine settlements. We assessed the explanatory and predictive power of settlement and landscape characteristics and were able to develop robust estimates of local faunal depletion. By identifying species specific drivers of depletion and using secondary data on human population density, land form, and physical accessibility, we then estimated landscape- and regional-scale depletion. White-lipped peccary (Tayassu pecari), for example, were estimated to be absent from 17% of their putative range in Brazil’s largest state (Amazonas), despite 98% of the original forest cover remaining intact. We found evidence that bushmeat consumption in small urban centers has far-reaching impacts on some forest species, including severe depletion well over 100 km from urban centers. We conclude that LEK-based approaches require further field validation, but have significant potential for community-based participatory monitoring as well as cost-effective, large-scale monitoring of threatened forest specie

Bilateral Jaw Elements in <i>Amiskwia sagittiformis</i> Bridge the Morphological Gap between Gnathiferans and Chaetognaths

Amiskwia sagittiformis Walcott 1911 is an iconic soft-bodied taxon from the Burgess Shale [1, 2, 3]. It was originally interpreted as a chaetognath [1], but it was later interpreted as a pelagic nemertean [2] or considered of uncertain affinity [3]. Part of this ambiguity is due to direct comparisons with members of the crown groups of extant phyla [4] and a lack of clarity regarding the systematic position of chaetognaths, which would allow for assessing character polarity in the phylum with respect to outgroups. Here, we show that Amiskwia preserves a bilaterally arranged set of head structures visible in relief and high reflectivity. These structures are best interpreted as jaws situated within an expanded pharyngeal complex. Morphological studies have highlighted a likely homology between bilateral and chitinous jaw elements in gnathiferans and chaetognaths [5], which is congruent with a shared unique Hox gene that suggests a close relationship between Gnathifera and Chaetognatha [6]. Molecular phylogenetic studies have recently found gnathiferans to be a deep branch of Spiralia and Chaetognaths either a sister group to Spiralia [7] or forming a clade with gnathiferans [6, 8]. Our phylogenetic analyses render Gnathifera paraphyletic with respect to Chaetognatha, and we therefore suggest that Amiskwia is best interpreted as a stem chaetognath, but crown gnathiferan

Wildlife harvest and consumption in Amazonia's urbanized wilderness

Urbanization of forested wilderness could threaten biodiversity if expanding cities drive demand for wildlife as food. We examined the scale and drivers of urban wildlife consumption in the forested pre-frontier of Brazilian Amazonia, defined as municipalities (n = 73) with over 90% of their original forest cover still intact. A representative survey of two pre-frontier cities indicated that virtually all urban households consume wildlife, including fish (99%), bush-meat (mammals and birds) (79%), chelonians (48%) and caimans (28%) – alarming evidence of an under-reported wild-meat crisis in the heart of Amazonia. We also report rapid growth of cities and inadequate resources to deter illegal consumption in this urbanized wilderness covering 1.86 million square kilometres. We evaluate relevant policy levers and conclude that poverty-alleviation programs may accelerate a long-term transition from consumption of wildlife as an economical source of protein for the poor to luxury food for the wealthy. We argue that innovative environmental governance could limit wildlife consumption to only harvest-tolerant species. Researchers and policy-makers should engage with policies and ideas that promote poverty alleviation and supply poor city-dwellers with affordable alternatives to eating wildlife

Investigation of residual stress in selective laser melting

Selective laser melting is an attractive technology, enabling the manufacture of customised, complex metallic designs, with minimal wastage. However, uptake by industry is currently impeded by several technical barriers, such as the control of residual stress, which have a detrimental effect on the manufacturability and integrity of a component. Indirectly, these impose severe design restrictions and reduce the reliability of components, driving up costs. This thesis documents work on investigating the generation of residual stresses created in the selective laser melting process by the use of a finite element thermo-mechanical model. The thermo-mechanical model incorporated an adaptive meshing strategy which was used in conjunction with the use of high performance computing facilities. These together significantly increased the computational throughput for simulating selective laser melting of a single layer. Additionally, a volumetric hatching method was created to generate the laser scan vectors used in the process, with the ability to both simulate and manufacture on selective laser melting machines. A number of studies were performed to better understand the effect of laser scan strategy on the generation of residual stress in selective laser melting. Using this model, a series of investigations were performed to understand the effect of scan strategy and scan area size on the generation of residual stress in this process. Further studies were also performed to investigate the role of laser parameters, geometry, and support structures in selective laser melting and their effect on the generation of residual stress. The studies showed a complex interaction between transient thermal history and the build-up of residual stress has been observed in two conventional laser scan strategies (unidirectional and alternating) investigated. The temperature gradient mechanism was discovered for the creation of residual stress and the scan area size had an effect on the temperature sustained within the region. The parametric study of the laser parameters showed that an increase in laser scan speed increased the melt pool aspect ratio, and increase in laser power increased the melt pool width. The parametric thermo-mechanical analysis revealed that the laser scan speed had the most influence on the magnitude and anisotropy of the residual stresses generated. Varying the hatch distance had little effect on the maximum magnitude of residual stresses generated, but decreasing the hatch distance significantly increased the level of yielding that occurred. A study of the geometrical effect on scan strategy revealed the importance of the thermal history on the transverse stresses generated, influenced by the arrangement of scan vectors. The higher magnitude longitudinal stresses had predictable behaviour; only dependent on the scan vector length and not the thermal history generated by the choice of laser scan geometry. It was shown that the laser scan strategy becomes less important for scan vector length beyond the typical 5 mm island sizes. From the study of the support structures, it was found the insulating properties of the metal powder used in selective laser melting provide a significant thermal resistance for the dissipation of heat, and caused uniform overheating across the scanned region. In particular, the analysis showed localised overheating using support structures, which affected the melt pool geometry, and the residual stresses generated due to resistance against dissipating heat. Additionally, lattice structures such as the double gyroid showed localised overheating occurs using repeated exposures of short scan vectors. Suitable scan strategies therefore need to be developed to account for support structures. A multi-scale methodology was developed by combining information from the meso -scale obtained from the thermo-mechanical model. This model was used to predict the mechanical response of amacro -scale part. This approach used the assumption that meso -scale regions in island scan strategies behave independently from each other. This assumption was verified by comparing with a thermo-mechanical analysis. This multi-scale method was applied to a 3D structure and also to a complex 2D geometrical shape. Performing the multi-scale analyses has verified that the proposed technique of superposition of meso-scale stress fields at the macro -scale is a valid technique. The main strengths of the proposed multi-scale method is the decoupling of the meso and macro scale analyses. This has the benefit of reducing computational cost of the macro -scale analysis because it is independent of the complexity of the meso -scale analysis, and only requires performing once. These strengths translate into large computational time savings and also great flexibility in the physics incorporated at each scale

How to identify food deserts in Amazonian cities?

Food deserts are areas without affordable access to healthy foods. This paper explores whether food deserts are present within urban areas of the Brazilian Amazon. The availability and price of a variety of food products was surveyed in a total of 304 shops, across 3 cities in 2015. Least-cost distances were calculated to estimate travel distance to access products, with map overlay used to help identify areas with poor access to a variety of healthy food - these were defined as food deserts