Global change pressures on soils from land use and management

Soils are subject to varying degrees of direct or indirect human disturbance, constituting a major global change driver. Factoring out natural from direct and indirect human influence is not always straightforward, but some human activities have clear impacts. These include land use change, land management, and land degradation (erosion, compaction, sealing and salinization). The intensity of land use also exerts a great impact on soils, and soils are also subject to indirect impacts arising from human activity, such as acid deposition (sulphur and nitrogen) and heavy metal pollution. In this critical review, we report the state-of-the-art understanding of these global change pressures on soils, identify knowledge gaps and research challenges, and highlight actions and policies to minimise adverse environmental impacts arising from these global change drivers. Soils are central to considerations of what constitutes sustainable intensification. Therefore, ensuring that vulnerable and high environmental value soils are considered when protecting important habitats and ecosystems, will help to reduce the pressure on land from global change drivers. To ensure that soils are protected as part of wider environmental efforts, a global soil resilience programme should be considered, to monitor, recover or sustain soil fertility and function, and to enhance the ecosystem services provided by soils. Soils cannot, and should not, be considered in isolation of the ecosystems that they underpin and vice versa. The role of soils in supporting ecosystems and natural capital needs greater recognition. The lasting legacy of the International Year of Soils in 2015 should be to put soils at the centre of policy supporting environmental protection and sustainable development.

Struggles over family land? Tree crops, land and labour in Ghana's Brong-Ahafo region

Agricultural land use in much of Brong-Ahafo region, Ghana has been shifting from the production of food crops towards increased cashew nut cultivation in recent years. This article explores everyday, less visible, gendered and generational struggles over family farms in West Africa, based on qualitative, participatory research in a rural community that is becoming increasingly integrated into the global capitalist system. As a tree crop, cashew was regarded as an individual man's property to be passed on to his wife and children rather than to extended family members, which differed from the communal land tenure arrangements governing food crop cultivation. The tendency for land, cash crops and income to be controlled by men, despite women's and young people's significant labour contributions to family farms, and for women to rely on food crop production for their main source of income and for household food security, means that women and girls are more likely to lose out when cashew plantations are expanded to the detriment of land for food crops. Intergenerational tensions emerged when young people felt that their parents and elders were neglecting their views and concerns. The research provides important insights into gendered and generational power relations regarding land access, property rights and intra-household decision-making processes. Greater dialogue between genders and generations may help to tackle unequal power relations and lead to shared decision-making processes that build the resilience of rural communities.

Effects of coastal managed retreat on mercury biogeochemistry

We investigated the impact of managed retreat on mercury (Hg) biogeochemistry at a site subject to diffuse contamination with Hg. We collected sediment cores from an area of land behind a dyke one year before and one year after it was intentionally breached. These sediments were compared to those of an adjacent mudflat and a salt marsh. The concentration of total mercury (THg) in the sediment doubled after the dyke was breached due to the deposition of fresh sediment that had a smaller particle size, and higher pH. The concentration of methylmercury (MeHg) was 27% lower in the sediments after the dyke was breached. We conclude that coastal flooding during managed retreat of coastal flood defences at this site has not increased the risk of Hg methylation or bioavailability during the first year. As the sediment becomes vegetated, increased activity of Hg-methylating bacteria may accelerate Hg-methylation rate.

Gendered struggles over land: shifting inheritance practices among the Serer in rural Senegal

Although women's land rights are often affirmed unequivocally in constitutions and international human rights conventions in many African countries, customary practices usually prevail on the ground and often deny women's land inheritance. Yet land inheritance often goes unnoticed in wider policy and development initiatives to promote women's equal access to land. This paper draws on feminist ethnographic research among the Serer ethnic group in two contrasting rural communities in Senegal. Through analysis of land governance, power relations and 'technologies of the self', this article shows how land inheritance rights are contingent on the specific effects of intersectionality in particular places. The contradictions of legal pluralism, greater adherence to Islam and decentralisation led to greater application of patrilineal inheritance practices. Gender, religion and ethnicity intersected with individuals' marital position, status, generation and socio-ecological change to constrain land inheritance rights for women, particularly daughters, and widows who had been in polygamous unions and who remarried. Although some women were aware that they were legally entitled to inherit a share of the land, they tended not to 'demand their rights'. In participatory workshops, micro-scale shifts in women's and men's positionings reveal a recognition of the gender discriminatory nature of customary and Islamic law and a desire to 'change with the times'. While the effects of 'reverse' discourses are ambiguous and potentially reinforce prevailing patriarchal power regimes, 'counter' discourses, which emerged in participatory spaces, may challenge customary practices and move closer to a rights-based approach to gender equality and women's land inheritance.

Understanding the resurgence of traditional authorities in post-apartheid South Africa

Drawing their power not from the ballot box but from a supposedly ancient wellspring of power, hereditary traditional authorities in postcolonial Africa have frequently posed challenges for incoming ‘democratic’ governments. The situation in post-apartheid South Africa is no different. However contentious their role under the colonial and apartheid systems of government was, the Constitution of the new South Africa (1996) recognised traditional authorities and afforded them opportunities for a political resurgence. This paper reviews the changing status of traditional authorities in the Eastern Cape Province over the twenty years since 1994. It explores the resurgence of the chiefs in relation to the consolidation of both democratic processes and of emergent, neo-patrimonial modes of government. It briefly considers the role of traditional authorities in three key and closely related spheres, namely the institution of the Eastern Cape House of Traditional Leaders, the question of how gender is handled by and within traditional institutions, and the continuing challenges of land administration and development in rural areas. In all these spheres, and in the face of real opposition, the voice and influence traditional authorities have emerged stronger than ever. We conclude by suggesting that as they are drawn deeper into governance and have to play a formal role in addressing the myriad institutional challenges, new questions will and should be asked about the status and influence of traditional authorities, and their substantive contribution to democracy in South Africa.

Legacy effects of grassland management on soil carbon to depth

The importance of managing land to optimise carbon sequestration for climate change mitigation is widely recognised, with grasslands being identified as having the potential to sequester additional carbon. However, most soil carbon inventories only consider surface soils, and most large scale surveys group ecosystems into broad habitats without considering management intensity. Consequently, little is known about the quantity of deep soil carbon and its sensitivity to management. From a nationwide survey of grassland soils to 1 m depth, we show that carbon in grasslands soils is vulnerable to management and that these management effects can be detected to considerable depth down the soil profile, albeit at decreasing significance with depth. Carbon concentrations in soil decreased as management intensity increased, but greatest soil carbon stocks (accounting for bulk density differences), were at intermediate levels of management. Our study also highlights the considerable amounts of carbon in sub-surface soil below 30cm, which is missed by standard carbon inventories. We estimate grassland soil carbon in Great Britain to be 2097 Tg C to a depth of 1 m, with ~60% of this carbon being below 30cm. Total stocks of soil carbon (t ha-1) to 1 m depth were 10.7% greater at intermediate relative to intensive management, which equates to 10.1 t ha-1 in surface soils (0-30 cm), and 13.7 t ha-1 in soils from 30-100 cm depth. Our findings highlight the existence of substantial carbon stocks at depth in grassland soils that are sensitive to management. This is of high relevance globally, given the extent of land cover and large stocks of carbon held in temperate managed grasslands. Our findings have implications for the future management of grasslands for carbon storage and climate mitigation, and for global carbon models which do not currently account for changes in soil carbon to depth with management.

The calculative turn in land value capture: lessons from the English planning system

For over three decades, negotiated planning obligations have been the primary form of land value capture in England. Diffusing and evolving over the last decade, a significant policy innovation has been the use of financial calculations to estimate the extent to which policies on planning obligations for actual, proposed development projects and in plan making affect the financial viability of development. This paper assesses the extent to which the use of financial appraisals has provided a robust, just and practical procedure to support land value capture. It is concluded that development viability appraisals are saturated with intrinsic uncertainty and that land value capture that is based on such calculations is, to some extent, capricious. In addition, clear incentives for developers and land owners to bias viability calculations, the economic dependence of many viability consultants on developers and land owners, a lack of transparency, contested or ambiguous guidance and the opportunities created by input uncertainty for bias are further failings. It is argued that how viability calculations are applied has been, is being and will continue to be shaped by power relations.

Interactions between climate change and land use change on biodiversity: attribution problems, risks, and opportunities

Global change drivers are known to interact in their effects on biodiversity, but much research to date ignores this complexity. As a consequence, there are problems in the attribution of biodiversity change to different drivers and, therefore, our ability to manage habitats and landscapes appropriately. Few studies explicitly acknowledge and account for interactive (i.e., nonadditive) effects of land use and climate change on biodiversity. One reason is that the mechanisms by which drivers interact are poorly understood. We evaluate such mechanisms, including interactions between demographic parameters, evolutionary trade-offs and synergies and threshold effects of population size and patch occupancy on population persistence. Other reasons for the lack of appropriate research are limited data availability and analytical issues in addressing interaction effects. We highlight the influence that attribution errors can have on biodiversity projections and discuss experimental designs and analytical tools suited to this challenge. Finally, we summarize the risks and opportunities provided by the existence of interaction effects. Risks include ineffective conservation management; but opportunities also arise, whereby the negative impacts of climate change on biodiversity can be reduced through appropriate land management as an adaptation measure. We hope that increasing the understanding of key mechanisms underlying interaction effects and discussing appropriate experimental and analytical designs for attribution will help researchers, policy makers, and conservation practitioners to better minimize risks and exploit opportunities provided by land use-climate change interactions.

Pre-Columbian ring ditch construction and land use on a “chocolate forest island” in the Bolivian Amazon

We present a palaeoecological investigation of pre-Columbian land use in the savannah “forest island” landscape of north-east Bolivian Amazonia. A 5700 year sediment core from La Luna Lake, located adjacent to the La Luna forest island site, was analysed for fossil pollen and charcoal. We aimed to determine the palaeoenvironmental context of pre-Columbian occupation on the site and assess the environmental impact of land use in the forest island region. Evidence for anthropogenic burning and Zea mays L. cultivation began ~2000 cal a BP, at a time when the island was covered by savannah, under drier-than-present climatic conditions. After ~1240 cal a BP burning declined and afforestation occurred. We show that construction of the ring ditch, which encircles the island, did not involve substantial deforestation. Previous estimates of pre-Columbian population size in this region, based upon labour required for forest clearance, should therefore be reconsidered. Despite the high density of economically useful plants, such as Theobroma cacao, in the modern forest, no direct pollen evidence for agroforestry was found. However, human occupation is shown to pre-date and span forest expansion on this site, suggesting that here, and in the wider forest island region, there is no truly pre-anthropogenic ‘pristine’ forest.

Resting metabolic rates of two orbweb spiders: A first approach to evolutionary success of ecribellate spiders

Spiders are considered conservative with regard to their resting metabolic rate, presenting the same allometric relation with body mass as the majority of land-arthropods. Nevertheless, web-building is thought to have a great impact on the energetic metabolism, and any modification that affects this complex behavior is expected to have an impact over the daily energetic budget. We analyzed the possibility of the presence of the cribellum having an effect on the allometric relation between resting metabolic rate and body mass for an ecribellate species (Zosis geniculata) and a cribellate one (Metazygia rogenhoferi), and employed a model selection approach to test if these species had the same allometric relationship as other land-arthropods. Our results show that M. rogenhoferi has a higher resting metabolic rate, while Z. geniculata fitted the allometric prediction for land arthropods. This indicates that the absence of the cribellum is associated with a higher resting metabolic rate, thus explaining the higher promptness to activity found for the ecribellate species. If our result proves to be a general rule among spiders, the radiation of Araneoidea could be connected to a more energy-consuming life style. Thus, we briefly outline an alternative model of diversification of Araneoidea that accounts for this possibility. (C) 2011 Elsevier Ltd. All rights reserved.

Assessing the impact of deforestation and climate change on the range size and environmental niche of bird species in the Atlantic forests, Brazil

Aim Habitat loss and climate change are two major drivers of biological diversity. Here we quantify how deforestation has already changed, and how future climate scenarios may change, environmental conditions within the highly disturbed Atlantic forests of Brazil. We also examine how environmental conditions have been altered within the range of selected bird species. Location Atlantic forests of south-eastern Brazil. Methods The historical distribution of 21 bird species was estimated using Maxent. After superimposing the present-day forest cover, we examined the environmental niches hypothesized to be occupied by these birds pre- and post-deforestation using environmental niche factor analysis (ENFA). ENFA was also used to compare conditions in the entire Atlantic forest ecosystem pre- and post-deforestation. The relative influence of land use and climate change on environmental conditions was examined using analysis of similarity and principal components analysis. Results Deforestation in the region has resulted in a decrease in suitable habitat of between 78% and 93% for the Atlantic forest birds included here. Further, Atlantic forest birds today experience generally wetter and less seasonal forest environments than they did historically. Models of future environmental conditions within forest remnants suggest generally warmer conditions and lower annual variation in rainfall due to greater precipitation in the driest quarter of the year. We found that deforestation resulted in a greater divergence of environmental conditions within Atlantic forests than that predicted by climate change. Main conclusions The changes in environmental conditions that have occurred with large-scale deforestation suggest that selective regimes may have shifted and, as a consequence, spatial patterns of intra-specific variation in morphology, behaviour and genes have probably been altered. Although the observed shifts in available environmental conditions resulting from deforestation are greater than those predicted by climate change, the latter will result in novel environments that exceed temperatures in any present-day climates and may lead to biotic attrition unless organisms can adapt to these warmer conditions. Conserving intra-specific diversity over the long term will require considering both how changes in the recent past have influenced contemporary populations and the impact of future environmental change.

Historical carbon budget of the brazilian ethanol program

This work models the carbon neutralization capacity of Brazil`s ethanol program since 1975. In addition to biofuel, we also assessed the mitigation potential of other energy products, such as, bioelectricity, and CO(2) emissions captured during fermentation of sugar cane`s juice. Finally, we projected the neutralization capacity of sugar cane`s bio-energy system over the next 32 years. The balance between several carbon stocks and flows was considered in the model, including the effects of land-use change. Our results show that the neutralization of the carbon released due to land-use change was attained only in 1992, and the maximum mitigation potential of the sugar cane sector was 128 tonnes Of CO(2) per ha in 2006. An ideal reconstitution of the deployment of the sugar cane sector, including the full exploitation of bio-electricity`s potential, plus the capture Of CO(2) released during fermentation, shows that the neutralization of land-use change emissions would have been achieved in 1988, and its mitigation potential would have been 390 tCO(2)/ha. Finally, forecasts of the sector up to 2039 shows that the mitigation potential in 2039 corresponds to 836 tCO(2)/ha, which corresponds to 5.51 kg Of CO(2) per liter of ethanol produced, or 55% above the negative emission level. (C) 2009 Elsevier Ltd. All rights reserved.

A Visibility Analysis of the Cape Wind Project

Cape Wind has proposed a wind farm of 130 turbines on Horseshoe Shoal in the center of Nantucket Sound. A prominent concern about the project is the impact the visibility of the turbines will have on the region's tourism industry and property values. It is feared that their presence will diminish the value of the pristine coastline that has attracted vacationers to Cape Cod for generations. In this project, we assess the extent to which Cape Cod, Martha's Vineyard, and Nantucket will be visually affected by the wind farm. It was completed using a Viewshed Analysis in the GIS program, ArcMap, from the surface, mean, and maximum height of the towers. These Viewsheds were combined to give a comprehensive perspective of which areas are able to see the highest percent of the wind farm. Finally, a weighted land use value was applied to the Viewshed to account for the impact of land use on the ability to see the project. The objective of this analysis is to provide a visual representation of how great an influence the wind farm will in fact have on Cape Cod.

Prioritizing Land Purchases for the Belgrade Regional Conservation Alliance

The Belgrade Regional Conservation Alliance is an organization that is dedicated to preserving land and water quality in the Belgrade Lakes region in Maine. The BRCA holds land in such towns as Belgrade, Mount Vernon, New Sharon, Vienna, Rome, Smithfield, and Oakland. The BRCA is looking to expand its acreage in and around these areas to better accommodate the public and to promote the ongoing effort to conserve land as part of the Kennebec Highlands Project. The BRCA is currently considering parcels of 50+ acres in New Sharon, Rome, Belgrade, and Mount Vernon. In order to identify possible suitable parcels, we completed a GIS analysis and produced these layered maps, which highlight areas of land that we think might be desirable to the BRCA. Our analysis encompasses human access, wildlife access, and the locations and sizes of parcels.