Spatial Assessment Model Research Articles

The atlas of unburnable oil for supply-side climate policies

To limit the increase in global mean temperature to 1.5 °C, CO2 emissions must be drastically reduced. Accordingly, approximately 97%, 81%, and 71% of existing coal and conventional gas and oil resources, respectively, need to remain unburned. This article develops an integrated spatial assessment model based on estimates and locations of conventional oil resources and socio-environmental criteria to construct a global atlas of unburnable oil. The results show that biodiversity hotspots, richness centres of endemic species, natural protected areas, urban areas, and the territories of Indigenous Peoples in voluntary isolation coincide with 609 gigabarrels (Gbbl) of conventional oil resources. Since 1524 Gbbl of conventional oil resources are required to be left untapped in order to keep global warming under 1.5 °C, all of the above-mentioned socio-environmentally sensitive areas can be kept entirely off-limits to oil extraction. The model provides spatial guidelines to select unburnable fossil fuels resources while enhancing collateral socio-environmental benefits.

Spatial awareness: Good practices and pragmatic recommendations for developing spatially structured stock assessments

Spatial population structure is a fundamental aspect of marine populations, yet it is rarely incorporated in stock assessment models. The unit stock assumption, a common feature of many assessments, is an axiom of the single-species modeling convention, which developed in the mid-20th century when the spatial resolution of fishery data was coarse and uncertain, computing power limited, and the impact of biocomplexity on sustainable harvest levels not well understood. Despite rapid advances along all of these research fronts in the 21st century, spatial assessments remain rarely utilized as the basis of management decision-making. A potential hindrance to broader utilization of spatial stock assessments is the lack of guidance on how to choose an appropriate spatial modeling framework for a given application. Thus, we review the types of spatial assessment models available, summarize options to parameterize population structure, offer guidance to promote the development of candidate spatial assessment models for application in management procedures, and provide a pragmatic guide for choosing a spatial assessment model given observed spatial structure, data limitations, and management concerns. A spatial assessment should match the assessment unit(s) to interdisciplinary stock identification of unit populations, adequately represent the spatial structure within an assessment unit, simultaneously model multiple interacting population units, when appropriate, and provide outputs for managers that can be used to prevent local depletion of spawning populations. As data permits, higher resolution intra-population spatial structure can be addressed to increase homogeneity within the modeled unit, while connectivity among population units may also be explicitly incorporated. Small sample sizes can limit spatial assessment applications, but incorporating novel data sources and parameterizing models efficiently (e.g., sharing parameters among spatial units, implementing habitat preference functions to improve movement dynamics, and including spatial autocorrelation) can resolve some practical constraints. Management strategy evaluation should be more widely utilized to identify minimally complex management procedures that provide robust advice, while imprecision of spatial models should be weighed against the inherent bias of spatially aggregated assessments.

Revisiting ‘Sabil’ buildings as nuclei of sustainable urban mobility in Fatimid Cairo: An urban-touristic approach considering urban and environmental qualities

This study adopts two levels of comparative urban analysis to investigate the current role played by Sabil buildings as nuclei for sustainable urban rehabilitation in Al-Muiz Street, Fatimid Cairo, Egypt. The study is tackled from an urban touristic approach to promote linear and diffused mobility. Hence, Linear Urban Mobility Analysis divided the linear spine into nine sectors based on Sabil locations. These varied in densities, activities, services, social behaviour and opportunities. They were compared based on a matrix including quantitative and qualitative parameters reflecting the existing urban conditions, and were added to an ArcGIS ModelBuilder to develop a spatial assessment model. Then, for a Diffused Urban Mobility Analysis, three proposed itineraries were compared using validated software programs to scrutinise their urban and environmental qualities. The results present a pilot study for promoting sustainable urban mobility in historic cities based on Sabil buildings contextual settings.

Assessing Ecosystem and Urban Services for Landscape Suitability Mapping

Ecosystem services (ES) and urban services (US) can comparably improve human well-being. Models for integrating ES and US with unexpressed and objective needs of defined groups of stakeholders may prove helpful for supporting decisions in landscape planning and management. In fact, they could be applied for highlighting landscape areas with different characteristics in terms of services provided. From this base, a suitability spatial assessment model (SUSAM) was developed and applied in a study area considering different verisimilar scenarios that policy makers could analyse. Each scenario is based on the prioritization of a set of services considering a defined group of stakeholders. Consistent and comparable ES and US indices of spatial benefiting areas (SBA) of services were calculated using GIS spatialization techniques. These indices were aggregated hierarchically with the relevance of services according to a spatial multicriteria decision analysis (S-MCDA). Results include maps for each scenario showing detailed spatial indices of suitability that integrate the local availability of SBA of ES and US, along with their relevance. The results were compared with known landscape classes identified in previous studies, which made it possible to interpret the spatial variation of suitability in the light of known landscape features. A complete sensitivity analysis was performed to test the sensitiveness of the model’s outputs to variations of judgements and their resistance to the indicators’ variation. The application of the model demonstrated its effectiveness in a landscape suitability assessment. At the same time, the sensitivity analysis and helping to understand the model behaviour in the different landscape classes also suggested possible solutions for simplifying the whole methodology.

Spatial assessment models to evaluate human health risk associated to soil potentially toxic elements.

Quantifying source apportionment of potentially toxic elements (PTEs) in soils and associated human health risk (HHR) is essential for soil environment regulation and pollution risk mitigation. For this purpose, an integrated method was proposed, and applied to a dataset consisting of As, Cd, Cr, Cu, Hg, Ni, Pb, Se, and Zn in 273 soil surface samples. Positive matrix factorization (PMF) was used to quantitatively examine sources contributions of PTEs in soils; and the HHR arising from the identified source was determined by combining source profiles and health risk assessment; at last, sequential Gaussian simulation (SGS) was used to identify the areas with high HHR. Four sources were identified by PMF. Natural and agricultural sources affected all 9 PTEs contents with contributions ranging from 19.2% to 62.9%. 41.9% of Cd, 40.8% of Pb, 58.6% of Se, and 29.8% of Zn were controlled by industrial and traffic emissions. Metals smelting and mining explained 35.5%, 30.5%, and 24.9% of Cr, Cu, and Ni variations, respectively. Hg was dominated by atmospheric deposition from coal combustion and coking (58.7%). The mean values of the total non-carcinogenic risks of PTEs were 1.55×10-1 and 9.40×10-1 for adults and children, and the total carcinogenic risk of PTEs had an average value of 8.86×10-5. Based on source-oriented HHR calculation, natural and agricultural sources were the most important factor influencing HHR, explaining 51.0% and 49.1% of non-carcinogenic risks for children and adults, and 44.2% of carcinogenic risk. SGS indicated that 1.1% of the total area was identified as hazardous areas with non-carcinogens risk for children.

Exploring the utility of different tag-recovery experimental designs for use in spatially explicit, tag-integrated stock assessment models

The need for spatial stock assessment models that match the spatiotemporal management and biological structure of marine species is growing. Spatially explicit, tag-integrated models can emulate complex population structure, because they are able to estimate connectivity among population units by incorporating tag-recovery data directly into the combined objective function of the assessment. However, the limited scope of many small-scale tagging studies along with difficulty addressing major assumptions of tagging data has prevented more widespread utilization of tag-recovery data sets within tag-integrated models. A spatially explicit simulation-estimation framework that simulates metapopulation dynamics with two populations and time-varying connectivity was implemented for three life history (i.e., longevity) scenarios to explore the relative utility of tagging data for use in spatial assessment models across a range of tag release designs (e.g., annual, historical, periodic, and opportunistic tagging). Model scenarios also investigated the impacts of not accounting for incomplete tag mixing or assuming all fish were fully selected (i.e., that the age composition of tagged fish was unknown). Results demonstrated that periodic tagging (e.g., releasing tags every five years) may provide the best balance between tag program cost and parameter bias. For cost-effective tagging programs, tag releases should be spread over a longer time period instead of focusing on release events in consecutive years, while releasing tags in tandem with existing surveys could further improve the practicality of implementing tag-recovery experiments. However, care should be taken to fully address critical modeling assumptions (e.g., by estimating tag mixing parameters) before incorporating tagging data into an assessment model.

Mapping the conservation priority of migratory shorebird habitat on a dynamic deltaic coast

Shorebird habitat degradation and loss due to high-intensity disturbances from human activities and the negative effects of global climate change in coastal deltas have led to the need to identify and designate priority areas for conservation with different levels of protection. We have proposed an integrated framework and model for the management of priority shorebird habitats in dynamic coastal delta zones (MPH-DC) based on a fuzzy spatial assessment model that incorporates habitat importance and disturbance analyses. By evaluating the relationships between shorebird populations and key ecological habitats, 19 structural factors, including land cover type, vegetation structure, terrain, potential human influence and natural interference, were derived from multi-temporal optical and radar remotely sensed imagery and incorporated into the index system to evaluate habitat conservation priority levels for Charadriidae and Anatidae in the Changjiang estuary, a typical coastal habitat that currently faces enormous challenges but is not yet under dynamic conservation priority management at a large spatial-temporal scale. The use of the MPH-DC framework proved to be effective for evaluating the spatial distribution and conservation priority of habitats in dynamic coastal deltas and for rapidly identifying regions where restoration and priority adjustment are needed, thus enriching broad-scale integrated ecosystem management solutions for coastal deltaic zones.

Space oddity: The mission for spatial integration

Fishery management decisions are commonly guided by stock assessment models that aggregate outputs across the spatial domain of the species. With refined understanding of spatial population structures, scientists have begun to address how spatiotemporal mismatches among the scale of ecological processes, data collection programs, and stock assessment methods (or assumptions) influence the reliability and, ultimately, appropriateness of regional fishery management (e.g., assigning regional quotas). Development and evaluation of spatial modeling techniques to improve fisheries assessment and management have increased rapidly in recent years. We overview the historical context of spatial models in fisheries science, highlight recent advances in spatial modeling, and discuss how spatial models have been incorporated into the management process. Despite limited examples where spatial assessment models are used as the basis for management advice, continued investment in fine-scale data collection and associated spatial analyses will improve integration of spatial dynamics and ecosystem-level interactions in stock assessment. In the near future, spatiotemporal fisheries management advice will increasingly rely on fine-scale outputs from spatial analyses.

Landscape liveability spatial assessment integrating ecosystem and urban services with their perceived importance by stakeholders

In recent years, landscape liveability has become a leading objective in policy and strategic planning. In the anthropocentric view of landscape, ecosystems fulfil important societal needs similarly to urban systems. Urban systems can meet a variety of such needs through Urban Services, which are historically and typically provided within cities. In this view, Ecosystem Services (ES) and Urban Services (US) influence landscape liveability in a comparable manner, so that liveability assessments based on both ES and US can be effective for landscape planning and policy-making purposes. As liveability is strongly dependent not only on objective landscape features, but also on the subjective perception of stakeholders, their involvement becomes essential for a coherent liveability assessment. The present study aims to develop a LIveability Spatial Assessment Model (LISAM) capable of considering both the local accessibility of services and their perceived relevance as expressed by stakeholders. To this end, a conceptual framework to detangle the spatial relationships between service sources, sinks, and delivery points was developed. From this base, consistent and comparable ES and US indices were calculated using GIS spatialisation techniques and then aggregated hierarchically through a Spatial Multicriteria Decision Making Analysis approach. Results include relevant maps showing explicit spatial indices of liveability that integrate, at various hierarchical levels, the local accessibility of ES and US, along with their local perceived relevance. By calculating complex indices able to highlight both the agri-natural and urban system roles on landscape liveability and by taking subjective and objective aspects into account, the model proved to be effective for spatial decision-making. In future applications, indicator and weight uncertainties should be considered and adequately analysed to assess reliability of the final output. The integration of ecosystem and urban disservices would also be relevant for including those landscape factors that reduce the overall level of place liveability.

A method to the impact assessment of the returning grazing land to grassland project on regional eco-environmental vulnerability

The Chinese government has conducted the Returning Grazing Land to Grassland Project (RGLGP) across large portions of grasslands from western China since 2003. In order to explore and understand the impact in the grassland's eco-environment during the RGLGP, we utilized Projection Pursuit Model (PPM) and Geographic Information System (GIS) to develop a spatial assessment model to examine the ecological vulnerability of the grassland. Our results include five indications: (1) it is practical to apply the spatial PPM on ecological vulnerability assessment for the grassland. This methodology avoids creating an artificial hypothesis, thereby providing objective results that successfully execute a multi-index assessment process and analysis under non-linear systems in eco-environments; (2) the spatial PPM is not only capable of evaluating regional eco-environmental vulnerability in a quantitative way, but also can quantitatively demonstrate the degree of effect in each evaluation index for regional eco-environmental vulnerability; (3) the eco-environment of the Xianshui River Basin falls into the medium range level. The normalized difference vegetation index (NDVI) and land use cover and change (LUCC) crucially influence the Xianshui River Basin's eco-environmental vulnerability. Generally, in the Xianshui River Basin, regional eco-environmental conditions improved during 2000 and 2010. The RGLGP positively affected NDVI and LUCC structure, thereby promoting the enhancement of the regional eco-environment; (4) the Xianshui River Basin divides its ecological vulnerability across different levels; therefore our study investigates three ecological regions and proposes specific suggestions for each in order to assist in eco-environmental protection and rehabilitation; and lastly that (5) the spatial PPM established by this study has the potential to be applied on all types of grassland eco-environmental vulnerability assessments under the RGLGP and under the similar conditions in the Returning Agriculture Land to Forest Project (RALFP). However, when establishing an eco-environmental vulnerability assessment model, it is necessary to choose suitable evaluation indexes in accordance with regional eco-environmental characteristics.

Quantifying northward movement rates of eastern king prawns along eastern Australia

Movement rates of eastern king prawns, Melicertus plebejus (Hess), were estimated from historical and recent conventional tag-recapture information collected across eastern Australia. Data from three studies and 2,656 tag recaptures were used. Recaptured males and females both moved east–north-east in central Queensland and north–north-east in southern Queensland and New South Wales. Over a period of one year, the estimated transition matrix reflected the species strong northerly movement and the more complex longitudinal movement, showing a very high probability of eastern movement in central Queensland and almost negligible eastern or western movement in northern New South Wales. The high exchange probability between New South Wales and Queensland waters indicated that spatial assessment models with movement rates between state jurisdictions would improve the management of this single-unit stock.

Multispecies spatial assessment models for the British Columbia groundfish trawl fishery

A multispecies spatial model is proposed for evaluation of trawl management strategies and tested with data from British Columbia groundfish. Minimum stock sizes are estimated for 16 species using spatial catch per unit effort data; these data indicate that only small proportions of most stocks are exposed to fishing at any time and that exchange rates of fish between the grounds and other habitats are rapid. A gravity model for spatial effort allocation predicts substantial side effects of marine protected areas or discarding of particular species on nontarget species/grounds due to redistribution of fishing effort. Multispecies, multiground delay-difference models are used in conjunction with the gravity model for spatial effort distribution to predict long-term population responses to various regulatory strategies. This simulation suggests that species composition and spatial structure of the fishery are changing slowly due to reduction in abundance of long-lived species, but rapid collapses of target stocks are unlikely due to spatial redistribution of effort in response to local declines. We question whether quota management (individual vessel quotas) can be safely implemented due to extreme uncertainty about current stock sizes and suggest that a better strategy may be to simply denominate fishing rights as individual effort quotas while providing protection for sensitive stocks through carefully placed marine protected areas.

Multispecies spatial assessment models for the British Columbia groundfish trawl fishery

Multispecies spatial assessment models for the British Columbia groundfish trawl fishery