Large herbivores and carnivores (the megafauna) have been in a state of decline and extinction since the Late Pleistocene, both on land and more recently in the oceans. Much has been written on the ...timing and causes of these declines, but only recently has scientific attention focused on the consequences of these declines for ecosystem function. Here, we review progress in our understanding of how megafauna affect ecosystem physical and trophic structure, species composition, biogeochemistry, and climate, drawing on special features of PNAS and Ecography that have been published as a result of an international workshop on this topic held in Oxford in 2014. Insights emerging from this work have consequences for our understanding of changes in biosphere function since the Late Pleistocene and of the functioning of contemporary ecosystems, as well as offering a rationale and framework for scientifically informed restoration of megafaunal function where possible and appropriate.
Free-living mammals, such as humans and wild mice, display heightened immune activation compared with artificially maintained laboratory mice. These differences are partially attributed to microbial ...exposure as laboratory mice infected with pathogens exhibit immune profiles more closely resembling that of free-living animals. Here, we examine how colonization by microorganisms within the natural environment contributes to immune system maturation by releasing inbred laboratory mice into an outdoor enclosure. In addition to enhancing differentiation of T cell populations previously associated with pathogen exposure, outdoor release increased circulating granulocytes. However, these “rewilded” mice were not infected by pathogens previously implicated in immune activation. Rather, immune system changes were associated with altered microbiota composition with notable increases in intestinal fungi. Fungi isolated from rewilded mice were sufficient in increasing circulating granulocytes. These findings establish a model to investigate how the natural environment impacts immune development and show that sustained fungal exposure impacts granulocyte numbers.
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•Controlled release of lab mice into the wild alters the state of the immune system•Rewilded mice harbor an altered microbiota including increases in intestinal fungi•Fungi from rewilded mice induce granulocyte expansion in laboratory mice
Laboratory mice are maintained in artificial conditions that potentially impact immunity. In this issue of Cell Host & Microbe, Yeung et al. (2020) demonstrate that mice released into a wild enclosure display increases in circulating granulocytes that are associated with an altered microbiota, notably expansion of fungi.
Trophic rewilding: impact on ecosystems under global change Bakker, Elisabeth S.; Svenning, Jens-Christian
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
10/2018, Volume:
373, Issue:
1761
Journal Article
Rewilding is growing worldwide as a conservation approach to face the restoration of all natural processes that are suppressed or degraded by human action. After plenty of theoretical discussion and ...some limited experimental practices, rewilding remained conceptually open and diverse with regard to its operational framework. However, little was discussed with regards invasive alien species (IAS) management within rewilding. Hence, the aim of this research is to bridge the gap between these two bodies of theory. To do so, this work explores, in situ, a protected area in which rewilding is discoursively expressed as a form of native forest conservation. Based on a qualitative approach, the results gather stakeholders’ discourses on the institutional advocacy for rewilding, expressed as a form of incentivizing land abandonment and hence leading to a decline in the plantation of invasive blue gums (Eucalyptus globulus). The research poses a discussion on the problematic assimilation that rewilding and IAS management may have when informally combined. Lastly, it is concluded that, when executed in coexistence with IAS, rewilding projects should elude reactive positions and, instead, formalize agreed restoration programs, so that conflictive IAS can be consensually treated together with landowners.
Abstract
Rewilding is an emotional subject. It inspires passions and argument in spades. As a form of conservation, rewilding offers exciting possibilities to address ecological crises but it is also ...a threat for many people, leading to dispute and impasse. This paper explores the role emotions play both to inspire rewilding and in the ensuing conflicts. Informed by emotional geographies and feminist political ecology, the analysis attends to the socio‐cultural differences underpinning emotional response and argues that emotions need to be taken seriously to better understand the socio‐natural processes underway. Unravelling the work that emotions do, the experience of joy, arising from time spent in nature, is seen to initiate a desire for rewilding amongst activists. By contrast, for opponents, rewilding prompts a sense of anger, which arises in response to a perceived threat to their identity as farmers and associated feelings of vulnerability. Critically, this vulnerability often remains occluded by the dominance of anger within debates, which explains why conflict has become so intractable. However, by attending to the full register of emotions at work, including those that are not always surfaced, and by better understanding the basis of such emotions, an avenue towards greater empathy is proposed.
Short Abstract
The role of emotions in rewilding activism and conflict is explored, following insights from feminist scholarship. The experience of joy, arising from time spent in nature, is formative to initiating rewilding activism. The anger of those opposing rewilding is linked to the threat they perceive to their sense of identity. Emotional vulnerability plays a critical role in making rewilding conflict so intractable, but could offer a basis for greater empathy.
In contrast to that of the Pleistocene epoch, between approximately 2.6 million and 10 000 years before present, the extant community of large herbivores in Arctic tundra is species-poor ...predominantly due to human extinctions. We here discuss how this species-poor herbivore guild influences tundra ecosystems, especially in relation to the rapidly changing climate. We show that present herbivore assemblages have large effects on tundra ecosystem composition and function and suggest that the effect on thermophilic species expected to invade the tundra in a warmer climate is especially strong, and that herbivores slow ecosystem responses to climate change. We focus on the ability of herbivores to drive transitions between different vegetation states. One such transition is between tundra and forest. A second vegetation transition discussed is between grasslands and moss- and shrub-dominated tundra. Contemporary studies show that herbivores can drive such state shifts and that a more diverse herbivore assemblage would have even higher potential to do so. We conclude that even though many large herbivores, and especially the megaherbivores, are extinct, there is a potential to reintroduce large herbivores in many arctic locations, and that doing so would potentially reduce some of the unwanted effects of a warmer climate.
This article is part of the theme issue ‘Trophic rewilding: consequences for ecosystems under global change’.
Rewilding has become a new paradigm to promote the natural recovery of many flagship species, including large carnivores. A better understanding of the factors that drive rewilding processes would ...allow predicting these in order to support them where desirable. Yet large-scale assessments of the factors that favor or limit mammal populations of conservation concern remain rare in Europe. This study sought to monitor changes in Eurasian otter (Lutra lutra) occupation over the years to identify the factors limiting its recolonization. To this end, we monitored otter signs and spraints over 1238 sampling sites in southwest France from 2003 to 2005 and then over 615 sites in 2011–2012. We modeled this dataset in a multi-season occupancy framework using biotic and abiotic covariates identified as potentially affecting otter detection, distribution and/or colonization rates. As otters are a cryptic and mobile mammal, we integrated detection probability and spatial autocorrelation (contagion) into the modeling design. Otter occurrence was detected at 31 % of the sites surveyed in 2003–2005 and 37 % of the sites surveyed in 2011–2012. Occupancy and colonization probabilities were strongly negatively correlated to the proportion of cultivated areas. Contagion covariates interacted strongly with other variables. These results suggest that, despite its recent colonization, the otter population in southwest France is still constrained in its expansion, notably by intensive agriculture. Natura 2000 schemes should incorporate rewilding approaches to further potentiate the colonization of this flagship species. Actions should focus on the conservation of natural riparian habitats and promote organic agriculture.
•Otter populations recolonized rivers in southwest France between 2003 and 2012.•Occupancy and colonization were both constrained by areas of intensive agriculture.•Connection with otter-occupied catchments interacted strongly with other variables.•Otter detection varied between years, observers, stream width and human density.
The last forty years have seen a dramatic increase in the number of great cormorants (Phalacrocorax carbo) moving inland away from British coastlines. Britain’s largest inland colony currently reside ...at Walthamstow Wetlands, a nature reserve and functional reservoir system in northeast London, recently branded ‘Europe’s largest urban wetland’. Here, great cormorants are embroiled in contested ideas of nature. Celebrated by conservationists for their resilience and adaptability, yet hounded by anglers for launching ecological chaos on rivers and reservoirs and disrupting the balance that is imagined for urban recreational spaces. This paper argues for a more nuanced version of rewilding that acknowledges the biogeographical complexity and mobility of nonhumans in relation to radically altered ecologies and post-industrial urban environments. It uses the conceptual frame of more-than-human to examine the increased presence, mobility, and agency of great cormorants at Walthamstow Wetlands in terms of nonhuman autonomy and auto-rewilding. The findings demonstrate that the self-relocation and autonomous occupation of inland cormorants in Walthamstow are intimately entangled with human histories and activities, and that they are active alongside humans in creating novel ecosystems.
•Organic farming suffers from lower productivity than conventional agriculture because the use of pesticides, herbicides, and fertilizers is restricted.•Rewilding furnishes crops with lost properties ...that their ancestors once had to tolerate adverse environmental conditions.•Rewilding is in accordance with the values of organic breeding and would contribute to closing the yield gap.•New breeding techniques that involve methods of genetic engineering allow for rewilding in a way that the final crop cannot be distinguished from a crop bred by traditional means.
Organic farming is based on the concept of working ‘with nature’ instead of against it; however, compared with conventional farming, organic farming reportedly has lower productivity. Ideally, the goal should be to narrow this yield gap. In this review, we specifically discuss the feasibility of new breeding techniques (NBTs) for rewilding, a process involving the reintroduction of properties from the wild relatives of crops, as a method to close the productivity gap. The most efficient methods of rewilding are based on modern biotechnology techniques, which have yet to be embraced by the organic farming movement. Thus, the question arises of whether the adoption of such methods is feasible, not only from a technological perspective, but also from conceptual, socioeconomic, ethical, and regulatory perspectives.
Rewilding is an increasingly popular approach to ecosystem-level restoration whereby strengthening ecosystem resilience and functionality is achieved through restoring previously extirpated species ...and/or ecological processes. Although rewilding has been broadly applied in many systems globally, there are limited examples that use sociological information to inform multi-species restoration efforts under this paradigm. We surveyed Montana, USA residents representing five stakeholder groups (local ranchers, statewide ranchers, rural residents, urban residents and members of conservation organizations) to assess public attitudes and behaviors towards a suite of species and ecological processes targeted for multi-species restoration in the Northern Great Plains. We also evaluated levels of public support for conservation incentive programs that are commonly used as a mechanism to increase restoration potential on private lands. We found that there were differences in how stakeholders perceived and behaved towards species subject to or targeted for restoration. Species perceived as potential risks to humans and livestock, or possessing regulatory constraints, yielded more negative attitudes, had increased potential for negative behaviors, and support for incentives for those species was lacking. Conversely, we found that stakeholder attitudes towards conserving migration as an ecological process were generally favorable. Our results illustrate how using public tolerance as a metric of social suitability will reveal barriers to acceptance for individual species restoration as well as insights into potential mechanisms for increasing public support for rewilding. More broadly, our study highlights how achieving rewilding in working lands will require community engagement to increase public support and continued assessments of social processes that may limit multi-species restoration.
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