Ecological Hotspots Research Articles

Marine Heat Waves and the Influence of El Niño off Southeast Queensland, Australia

In this paper, we investigate the occurrence and spatial variability of marine heat waves (MHWs) off the southeast coast of Queensland, Australia. The focus is on identifying sea surface temperature (SST) variability in two key ecological hotspots located south of the Australian Great Barrier Reef. This coastal region is bordered in the east by the intensification zone of the East Australian Current (EAC). It includes Hervey Bay, which is part of a UNESCO declared marine biosphere and the Southeast Fraser Island Upwelling System. The analysis of remotely sensed SST for the period 1993 to 2016 identifies the largest number of MHW days for Hervey Bay with a mean length of 12 days. The maximum length of 64 days occurred during the austral summer 2005/2006. The years with the largest number of MHW days was found to occur following the El Nino events in 1998, 2010 and 2016. A cross-correlation and Empirical Orthogonal Function analysis identified a significant correlation with a time lag of seven months between SST anomalies in the Nino 3.4 region and the southeast Queensland coast. 78% of variance in SST anomalies is explained by the first mode of variability. The strength of the relationship with El Nino was spatially variable and the weakest in Hervey Bay. Due to its sheltered location and shallowness, it is argued that local weather patterns and air-sea fluxes influence this area more than the other two regions, where remotely forced changes in oceanic heat advection may have a stronger impact on generating MHWs. Biodiverse coastal shelf ecosystems are already under tremendous pressure due to human activities. This is likely to be compounded by continued climatic change and an increasing number of MHWs. Thus, similar studies are encouraged for other regional shelfs and smaller scale coastal systems.

Measuring popularity of ecological topics in a temporal dynamical knowledge network.

As interdisciplinary branches of ecology are developing rapidly in the 21st century, contents of ecological researches have become more abundant than ever before. Along with the exponential growth of number of published literatures, it is more and more difficult for ecologists to get a clear picture of their discipline. Nevertheless, the era of big data has brought us massive information of well documented historical literature and various techniques of data processing, which greatly facilitates the implementation of bibliometric analysis on ecology. Frequency has long been used as the primary metric in keyword analysis to detect ecological hotspots, however, this method could be somewhat biased. In our study, we have suggested a method called PAFit to measure keyword popularity, which considered ecology-related topics in a large temporal dynamical knowledge network, and found out the popularity of ecological topics follows the “rich get richer” and “fit get richer” mechanism. Feasibility of network analysis and its superiority over simply using frequency had been explored and justified, and PAFit was testified by its outstanding performance of prediction on the growth of frequency and degree. In addition, our research also encourages ecologists to consider their domain knowledge in a large dynamical network, and be ready to participate in interdisciplinary collaborations when necessary.

Identifying ecological hotspots in the United States and Norway: Turning ecosystem-based management into practice?

Ecosystem based management (EBM) is an ocean management theory that examines an ecosystem holistically, accounting for both human uses and natural processes. EBM has gained popularity due to growing conflicts over ocean space, fueled by increasing demands for natural resources and a rising awareness for environmental values. EBM asserts that by scoping short-term natural resource exploitation to allow for the preservation of the ecosystem's core structure and function, sustainable long-term exploitation can be achieved. Therefore, determining the ecosystem's structure and function is a main tenet to EBM. To translate EBM theory to practice, important ecological areas, or “ecological hotspots,” are identified to understand the core ecosystem spaces that drive overall function. Marine Spatial Planning (MSP) is a process in which to operationalize EBM theory, including ecological hotspots. The literature has taken time to assess EBM from the theoretical perspective, however few studies exist that examine EBM-MSP interactions as EBM theory is translated into practice and secondly compare approaches across countries. This paper focuses on a comparative analysis of how ecological hotspots were (or are being) identified within two ecosystems, the Barents Sea and Gulf of Maine. The EBM ocean plans to be assessed are the Norwegian Barents Sea-Lofoten ocean management plan (BSMP) and the U.S. Northeast Ocean Plan (NEOP). It is found that the motivating factors that prompted the development of the BSMP and NEOP influenced when and how quickly ecological hotspots were determined. This paper aims to contribute to the discussion revolving around how EBM-MSP decision-making processes are operationalized.

Migratory waterfowls from Europe as potential source of highly pathogenic avian influenza infection to Nigeria poultry

Highly pathogenic avian influenza H5N1 was detected for the first time in Nigeria and Africa in 2006. The source of the outbreak was not immediately clear, but scientific opinions favoured multiple introductions. The need to evaluate available epidemiological and virological data to demonstrate most probable source of introduction is important for focused control efforts. In this study, we described ten years (2006-2016) scientific observations available through ecology, epidemio-surveillance and molecular virology of avian influenza in Nigeria. Nigeria is geographically located in the tropical humid region with abundant wetlands presenting ideal ambience for birdlife. Ornithological evidence also showed that the country lies in the path of two major migratory flyways from Europe and Asia providing opportunities for co-mingling of different species and age of wild birds with resident birds. Genomic characterization including phylogenetic analysis revealed a high degree of homology among virus strains isolated in Nigeria and those detected in migratory birds from Europe suggesting common source epidemic. This study agreed with postulation that migratory wild birds from Europe may be responsible for the introduction of highly pathogenic avian influenza subtype H5N1 to Nigeria. Feral waterfowls around water bodies thereafter bridge transmission to domestic poultry holdings whereas local trade and movement of poultry and poultry products may further spread infection locally. In the light of this understanding, routine risk based sentinel surveillance for avian influenza in domestic waterfowls in ecological hotspots is recommended for early detection and response thereby saving economic losses and mitigating public health emergencies. Keywords: Avian influenza, Migratory waterfowls, Nigeria, Poultry

의사결정트리를 이용한 북한 지역의 환경생태적 우수 지역 평가

통일 이후 국토의 보전과 이용을 고려하는 계획의 수립을 위해서는 객관적이고 과학적인 국토 환경성평가 결과가 필요하다. 하지만 북한 지역에 구축되어 있는 환경공간정보가 제한적이기 때문에 기존 환경성평가 기법을 적용한 환경성평가 결과의 도출은 어렵다. 본 연구는 남한 지역의 식생지수들과 토지피복지도, 지형 자료에 의사결정트리기법을 적용하여 환경생태적 우수 지역을 분류하는 모델을 구축하고 이를 북한 지역에 적용함으로써 북한 지역의 환경생태적 우수 지역을 평가하였다. 모델의 검증을 위한 ROC 분석 결과 AUC가 0.85621로 높게 나타나 제안한 모델의 실용적 사용이 가능함을 확인하였다. 또한 본 연구의 모델을 적용하여 도출한 남한지역의 환경생태적 우수지역과 국토환경성평가지도의 환경생태적 평가 1등급 지역을 중첩 분석한 결과 80.04%의 높은 일치율을 확인하였다. 본 연구가 제안한 방법으로 구축한 북한 지역의 환경생태적 우수 지역은 향후 통일 이후 환경의 보전과 국토의 이용과 관련된 계획 수립에 크게 기여할 수 있을 것이라 판단된다.

Tourism as an incentive for rewilding: the conversion from cattle to game farms in Limpopo province, South Africa

ABSTRACTWildlife has represented the key tourist attractions in South Africa. Boasting the big five, pristine national parks and three of the world’s ecological hotspots, tourism is a growing sector in South Africa. In addition to wildlife viewing, South Africa also attracts wildlife hunters to a network of private game farms, and in some cases, these bring in higher gross income than nature reserves. In the South African context, private game farms draw local and international tourists often offering accommodation in a natural setting, and a range of nature-based activities. Given the commercial success of private game farms, a number of agricultural farms have been converted to game farms in recent years. This shift has been marked within the cattle farming sector of Limpopo Province, the region with which this study engages. Faced with the risks of diseases, drought, cost of land and labour, and the declining price of beef, game farms offered self-reliance, diversification of product, and reduced seasonality in earnings. Although driven by economic factors, the conversion to game farming is characterised by the reintroduction of large herbivores, is resulting in land cover change and an increase in biodiversity and is therefore argued to be a form of ‘rewilding’.

빈도비를 이용한 북한 환경생태적 우수 지역 평가

빈도비를 이용한 북한 환경생태적 우수 지역 평가

Seabirds as Ecological Indicators in Late Cretaceous Marine Environments

In modern marine ecosystems, seabirds are considered indicators of ecological hotspots because their biogeographic distribution is correlated with physical, chemical, and biological oceanographic factors. Pursuit diving seabirds – those that actively pursue prey underwater – are even more limited in distribution and closely tied to oceanographic factors, as diving ability is often gained at the expense of flight capabilities. Today, pursuit diving seabirds are generally restricted to waters cooler than 15ºC. By contrast, the Late Cretaceous was characterized by greenhouse climate and high sea levels that provided marine paleoenvironments with no modern analogs. Even though waters in the Western Interior Seaway (WIS) were warmer than 15ºC, they were host to pursuit diving seabirds called hesperornithiforms. The presence of hesperornithiforms in warm waters indicates that different biotic and abiotic factors affected Late Cretaceous epicontinental ecosystems than affect modern oceans. Together, ecosystem structure and the unique oceanographic factors characterizing epicontinental seas both contribute to differences in seabird biogeography between the Late Cretaceous and today.

Estuarine fish behavior around slotted water control structures in a managed salt marsh

Estuaries are composed of multiple interconnected habitat types used by transient fish species during their period of estuarine residency. Structural marsh management restricts habitat connectivity and impedes the movement of fishes among these habitat types by limiting access via water control structures (WCSs) between the managed area and the rest of the estuary. While some general information on fish passage rates is available, species-specific information on passage through WCSs is lacking for salt marsh fishes. We monitored tagged fishes from March 2012 through November 2013 using passive integrated transponder antenna arrays at two identical WCSs in the Calcasieu Lake estuary, Louisiana, USA, to assess the effect of slotted WCSs on fish behavior. A total of 420 individuals of 15 species was tagged and released at the WCSs; of these, 145 individuals representing 11 species were later detected at the WCSs. Five species comprised most (93%) of the detected individuals: Elops saurus (n = 60), Mugil cephalus (n = 43), Sciaenops ocellatus (n = 20), Pogonias cromis (n = 7), and Ariopsis felis (n = 5). Passage rates were low, with most of the observed fishes (n = 80) passing only once through the structures. Other than E. saurus, which was only observed migrating out of the managed marsh, no clear pattern in swimming direction was observed for the other species. Detected species were all present primarily during the summer and fall, however, diel activity at the structures varied by species. The WCSs in our study area appeared to attract and congregate fishes, functioning more like ecological hotspots, rather than simply facilitating fish passage.

Communally Nesting Migratory Birds Create Ecological Hot-Spots in Tropical Australia.

Large numbers of metallic starlings (Aplonis metallica) migrate annually from New Guinea to the rainforests of tropical Australia, where they nest communally in single emergent trees (up to 1,000 birds). These aggregations create dense and species-rich faunal “hot-spots”, attracting a diverse assemblage of local consumers that utilise this seasonal resource. The starlings nested primarily in poison-dart trees (Antiaris toxicaria) near the rainforest-woodland boundary. Surveys underneath these colonies revealed that bird-derived nutrients massively increased densities of soil invertebrates and mammals (primarily wild pigs) beneath trees, year-round. Flying invertebrates, nocturnal birds, reptiles, and amphibians congregated beneath the trees when starlings were nesting (the wet-season). Diurnal birds (primarily cockatoos and bush turkeys) aggregated beneath the trees during the dry-season to utilise residual nutrients when the starlings were not nesting. The abundance of several taxa was considerably higher (to > 1000-fold) under colony trees than under nearby trees. The system strikingly resembles utilisation of bird nesting colonies by predators in other parts of the world but this spectacular system has never been described, emphasizing the continuing need for detailed natural-history studies in tropical Australia.

Current potential of more sustainable biomass production using eco-efficient farming practices in Austria

Ecological evaluation approaches assess different levels of comprehensiveness depending on anthropogenic ecological pressures on natural material and biogeochemical cycles. In this research potentials of biomass integration in agricultural processes were evaluated and all parts of their full life cycles were replaced with ecological processes of low impact. A method that covers global resource availabilities, life cycle chains and their emissions to final compartments on earth’ spheres in a detailed way is Sustainable Process Index. This footprint calculator accumulates the total resource use of a full life cycle of a process chain in one number of m2 area. Current typical conventional agricultural cropping processes shall be made comparable to a strongly sustainable ecological footprint which could be achieved if heavy footprint measures would be replaced by those with smaller impacts in natural cycles. The production of maize grain is evaluated to find out the ecological hotspots. A comparison of business as usual conventional farming practice and ecological/organic farming practice is carried out. The evaluation results confirmed that fossil fuel consumption and application of mineral fertilizers along with pesticides are the main ecological hotspots. The ecological footprint and carbon footprint showed a bandwidth of 24,731 to 10,690 m2/tonne and 88.5 and 22.6 kg carbon dioxide equivalent per tonne maize grain production respectively. The shift from conventional farming practice to organic farming and use of biogas as fuel showed an ecological footprint reduction potential ranging from 22% to 57% while the carbon footprint reduction potential ranges from 38% to 74%. It proves that SPI footprint methodology is quite effective in locating ecological hotspots and finding alternate environment friendly solution in the life cycle of a process. The assessment results are very promising and indicate that a shift from conventional farming practices towards organic farming and the use of renewable energy sources have a huge potential to achieve a more sustainable agriculture and strengthen a regionally based economy.

Dynamische Generhaltung in Europas Wäldern: Paneuropäische Konzepte nehmen Gestalt an

Dynamic gene conservation in European forests: Pan-European concepts shaping up Forests in Europe consist mainly of wild, undomesticated tree populations showing high genetic variation that has been shaped by postglacial migration and manifold adaptations to their local environments. To conserve this genetic diversity, many European countries have developed programs for the conservation of forest genetic resources, which consist not only of seed orchards but also of forest stands for in situ gene conservation. The long-term aim of the so called “dynamic gene conservation” is the maintenance of the most important ecological and, on a longer time scale, evolutionary processes. In the European cooperation project EUFGIS, Pan-European minimum requirements for units of dynamic gene conservation in forests were developed. On the basis of these criteria, a common database of all these identified units was established. Moreover, the representativeness of the nominated conservation units for ecological zones and continental hot spots of genetic diversity was analyzed, and the vulnerability of the network under climate change was investigated. This analysis showed that the present network of dynamic conservation units for various tree species contains significant gaps in its ecological and phylogenetic representativeness and indicates that up to 65% of the nominated conservation units of a target tree species will be highly vulnerable under climate change. Therefore, the network of gene conservation units needs to be extended, and additional transnational conservation actions including European assisted migration schemes should be considered.

Social mapping of perceived ecosystem services supply – The role of social landscape metrics and social hotspots for integrated ecosystem services assessment, landscape planning and management

This paper contributes to the discussion on integrating societal considerations, stakeholders' perceptions and laymen knowledge into ecosystem services (ES) assessments. The paper illustrates how social mapping of perceived ES supply (or alternatively demand) can contribute to integrated ES assessment. Based on sketched locations of the, according to 38 respondents, most important ES at the local scale, we describe the perceived ES distribution with social landscape metrics (abundance, diversity, richness, risk, rarity) based on traditional landscape ecology indicators. We illustrate how social landscape metrics can inform ES management and planning and describe how synergies between ES as stated by the respondents differ from calculated synergies (the latter based on correlation coefficients between perceived ES abundance). We present indicators pointing to locations where (multiple) ES synergies are perceived by stakeholders (stated synergy index), and to conflicting ES and ES perceived to be at risk (risk index). Overlapping social ES hotspots based on the social landscape metrics with ES hotspots based on more traditional biophysical modelling (biophysical hotspots) and ecological inventories (ecological hotspots) results in social–ecological or social–biophysical hotspots, coldspots and warmspots relevant for nature and landscape planning, management and governance. Based on an analysis of the overlaps between social, biophysical and ecological hotspots on the one hand, and the contribution of ecological quality, land zoning categories and conservation statuses on the other hand, we discuss the added value of integrating social ES mapping in integrated ES assessment, above ES assessments based on biophysical or ecological attributes. Given the limited overlap between social hotspots and ecological or biophysical hotspots, we conclude that integrating stakeholders' mapping of perceived ES supply (or demand) into ES assessments is necessary to reflect the societal aspects of ES in ES assessments. However, with a limited sample of respondents, there is a risk of collectivisation of respondents' viewpoints as a common, societal stance. Moreover, the social landscape metrics are not suitable for describing the distribution of ES with low perceived abundance. Finally, we explain how social ES assessment can result in mainstreaming ES in planning, policy and practice.

Methods and participatory approaches for identifying social-ecological hotspots

Understanding the relationship between humans and their environment is essential for the planning and management of social-ecological systems but integration of social values with biophysical landscape information remains challenging. Identifying areas that are likely to be pivotal in land use planning decisions from both social and ecological perspectives provides one means of integration. Social-ecological “hotspots” represent valuable areas from both human and environmental perspectives but appropriate and valid methods for identifying such areas are under-developed. We applied an inductive research approach using empirical spatial data from a regional study in Australia to evaluate alternative methods for identifying social-ecological hotspots. Social data measuring the importance of the landscape was collected using public participation geographic information systems (PPGIS) while ecologically valuable areas were identified from species distributions and Zonation conservation prioritization software. We applied multiple importance thresholds (cut-offs) to separately identify and measure social and ecological hotspots, and then quantified the degree of spatial concurrence (overlap) when combining the layers to generate social-ecological hotspots. Based on the findings, we developed guidelines for identifying social-ecological hotspots under variable data conditions. We describe the practical implications of our findings by showing how the selected method for SES hotspot identification can enhance or limit the utility of hotspot analysis for decision support in regional conservation planning.

Pelagic ciliate communities within the Amundsen Sea polynya and adjacent sea ice zone, Antarctica

Polynyas, areas of open water surrounded by sea ice, are sites of intense primary production and ecological hotspots in the Antarctic Ocean. This study determined the spatial variation in communities of pelagic ciliates in an Amundsen Sea polynya (ASP) and adjacent sea ice zones (SIZ) during austral summer from February to March 2012, and the results were compared with biotic and abiotic environmental factors. The species number, abundance and biomass were higher in the ASP than SIZ. Canonical analysis indicated that the communities in the ASP were distinct from those under the sea ice. The pelagic ciliate community structure was closely correlated with environmental variability. Several primary environmental variables, both alone and in combination, were found to affect community spatial patterns. The ciliate biomasses in the ASP and SIZ areas were both significantly correlated with total and nano-Chl a. This analysis of the ciliated microzooplankton communities associated with high primary production provides new insights into the roles of ciliates in biogeochemical cycles in high-latitude polynyas. Additionally, our findings provide detailed data on the composition, distribution, and structure of polynya ciliate communities in the Amundsen Sea.

Commentary on Matthew Butkus' ‘Biodiversity, Ethics, and Human Health’

I applaud Matthew Butkus' efforts, as his endeavor to protect ecological hotspots is well intentioned. In a pragmatic vein, Butkus seeks to motivate moral action through appeal to egoistic motivati...

Effects of Slotted Water Control Structures on Nekton Movement within Salt Marshes

AbstractWater control structures (WCSs) restrict hydrological connectivity in salt marshes and thereby impede nekton movement within the greater habitat mosaic. Transient fishery species, which spawn outside salt marshes and must get past these barriers to reach spawning areas or salt‐marsh nurseries, are especially vulnerable to these structures. Water control structures incorporating slots (narrow vertical openings spanning most of the water column) are thought to improve nekton passage; however, few studies have directly examined nekton passage through WCS slots. Dual‐frequency identification sonar (DIDSON) acoustic imaging was used monthly (April–September 2010) on diurnal flood tides to examine nekton movement through 15‐cm‐wide slots at two identical WCSs located in Louisiana tidal marsh channels. Nekton behavior was compared between these WCSs and a nearby natural salt‐marsh creek. Examination of 12 h of subsampled acoustic data revealed large concentrations of salt‐marsh nekton at the WCSs (n = 2,970 individuals total), but passage rates through the slots were low (≤10% of total observed individuals migrated via the slots). Most migrating fish were observed leaving the managed area and swimming against a flood tide. The mean size of migrating individuals (∼25 cm TL) did not differ in relation to swimming direction (going into versus exiting the managed marsh) and was similar to that reported from other studies examining similar slot widths. Nekton formed congregations in the WCS channel, but no congregations were observed in the natural salt‐marsh creek, even though nekton species composition and sizes were similar among sites. The WCSs in our study appear to function as ecological hot spots, where large individuals may encounter enhanced foraging opportunities but also fishing mortality and where smaller individuals may experience greater predation rates.Received July 22, 2014; accepted February 13, 2015

Landscapes for Conservation of Biological Diversity with Focus onthe Northern Western Ghats of Maharashtra (NWGM)

National wellbeing is dependent on the productivity of its lands. Productivity is central to the interestof natural ecosystems and the systems of farming. Water is essential for sustaining life, for ensuring foodsecurity as well as for effectively driving all development projects. Security of water is ensured by securenatural ecosystems centered on biological diversity. The terms productivity and biological diversity aresynonymous therefore it is essential for all processes and projects of development to internalize the securityof biological diversity/natural ecosystems. The principle at present however is almost non-existent in alldevelopment programmes because had it been so the forest and environmental clearances would not beconsidered loud and clear as hurdles to development. Western Ghats are one of the ecological hotspots of theworld. The northern Western Ghats have diverse forests, protected areas, ecologically sensitive areasdeclared under law, ecologically sensitive tehsils and villages and sacred groves managed and maintained bylocal communities. There are significant catchments and watersheds, origins of important rivers, manysprings and lateritic plateaus with unique species assemblages that are characteristic only of the northernWestern Ghats. These units together constitute the foci of conservation of natural ecosystems. The tract hasseveral dams and the largest hydroelectric facility. It supports diverse economies including the most rapidlygrowing tourism industry with many visitor destinations and famous hill stations dotted across thesemountains. In order to ensure ecological security of these fragile mountain ecosystems it is necessary toaddress land use at the largest spatial scale recognized as the landscape. Landscape allows using thedisparities within its constituents—the mosaic of interacting land uses by creating opportunities forreducing their inter se contradictions. The paper discusses such opportunities and strategies at variousspatial scales.National wellbeing is dependent on the productivity of its lands. Productivity is central to the interestof natural ecosystems and the systems of farming. Water is essential for sustaining life, for ensuring foodsecurity as well as for effectively driving all development projects. Security of water is ensured by securenatural ecosystems centered on biological diversity. The terms productivity and biological diversity aresynonymous therefore it is essential for all processes and projects of development to internalize the securityof biological diversity/natural ecosystems. The principle at present however is almost non-existent in alldevelopment programmes because had it been so the forest and environmental clearances would not beconsidered loud and clear as hurdles to development. Western Ghats are one of the ecological hotspots of theworld. The northern Western Ghats have diverse forests, protected areas, ecologically sensitive areasdeclared under law, ecologically sensitive tehsils and villages and sacred groves managed and maintained bylocal communities. There are significant catchments and watersheds, origins of important rivers, manysprings and lateritic plateaus with unique species assemblages that are characteristic only of the northernWestern Ghats. These units together constitute the foci of conservation of natural ecosystems. The tract hasseveral dams and the largest hydroelectric facility. It supports diverse economies including the most rapidlygrowing tourism industry with many visitor destinations and famous hill stations dotted across thesemountains. In order to ensure ecological security of these fragile mountain ecosystems it is necessary toaddress land use at the largest spatial scale recognized as the landscape. Landscape allows using thedisparities within its constituents—the mosaic of interacting land uses by creating opportunities forreducing their inter se contradictions. The paper discusses such opportunities and strategies at variousspatial scales.

Unveiling abundance and distribution of planktonic Bacteria and Archaea in a polynya in Amundsen Sea, Antarctica

Polynyas, areas of open water surrounded by sea ice, are sites of intense primary production and ecological hotspots in the Antarctic Ocean. This study determined the spatial variation in communities of prokaryotes in a polynya in the Amundsen Sea using 454 pyrosequencing technology, and the results were compared with biotic and abiotic environmental factors. The bacterial abundance was correlated with that of phytoplankton, Phaeocystis spp. and diatoms. A cluster analysis indicated that the bacterial communities in the surface waters of the polynya were distinct from those under the sea ice. Overall, two bacterial clades, Polaribacter (20-64%) and uncultivated Oceanospirillaceae (7-34%), dominated the surface water in the polynya while the Pelagibacter clade was abundant at all depths (7-42%). The archaeal communities were not as diverse as the bacterial communities in the polynya, and marine group I was dominant (> 80%). Canonical correspondence analysis indicated that the oceanographic properties facilitated the development of distinct prokaryotic assemblages in the polynya. This analysis of the diversity and composition of the psychrophilic prokaryotes associated with high phytoplankton production provides new insights into the roles of prokaryotes in biogeochemical cycles in high-latitude polynyas.

LCA case study. Part 2: environmental footprint and carbon tax of cradle-to-gate for composite and stainless steel I-beams

Part 1 of this research investigated environmental footprint for the cradle-to-grave of a linear metre I-beam made from traditional and alternative materials which are stainless steel (316) and glass reinforced plastics (GRP). Results revealed that GRP generally produced less environmental footprint than stainless steel. The main contribution found in the cradle-to-gate caused by raw materials (90 %) and associated transportation (10 %). Certain impact categories of GRP were either equalled or higher than stainless steel I-beam including the climate change impact category. Therefore, part 2 of this research further investigates the ecological and economic hot spots of the cradle-to-gate of GRP I-beam and alternative supply chain scenarios. The potential carbon tax was also estimated under two different situations. GRP and stainless steel (316) are used to assess the environmental footprint and the economic impact of 6,098 m I-beams as a production volume in practice. The World ReCiPe midpoint and endpoint methods generated the life cycle inventory, characteristic and single score results for the environmental footprint. The economic impact estimated based on a simple cost calculation associated with the cradle-to-gate including material, production and transportation costs. The ecological and economic hot spots were identified and formed 12 supply chain scenarios. Both identified hot spots came from raw materials that used in large quantities, consumed higher electricity and delivered by road and water transportation over long travel distances. The climate change impact category and the potential carbon tax values are improved under the scenarios that use a supplier from countries that generate electricity from less coal-based energy source and involve less transportation in delivering the raw materials. Win–win and trade-off scenarios were revealed when comparing both impacts. The former scenario reduces material costs, the travel distances and using lower freight rate transportation that consumes less fuel such as shipping. The latter scenarios are often occurred by either attempting to reduce the environmental footprint from using less transportation but the raw material costs are suffered. Manufacturers may select the scenario based on their production constrains. Cradle-to-grave was discussed and shown the benefits in including steel recycling into the assessment which can equate the potential carbon tax of the stainless steel with some GRP I-beam scenarios. Future work can be enhanced by considering other factors in the practice of manufacturing system such as insurance cost and lead time.