Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a planetary-scale 'tipping point' highlights the need to improve biological forecasting by detecting early warning signs of critical transitions on global as well as local scales, and by detecting feedbacks that promote such transitions. It is also necessary to address root causes of how humans are forcing biological changes.
We address criticism that the Transport, Establishment, Abundance, Spread, Impact (TEASI) framework does not facilitate objective mapping of risk assessment methods nor defines best practice. We explain why TEASI is appropriate for mapping, despite inherent challenges, and how TEASI offers considerations for best practices, rather than suggesting one best practice. Our review of alien species risk assessments (RA) (Leung et al. 2012) aimed to synthesise the diverse approaches applied in this field to establish a logical framework for best practices. We believe the TEASI framework that makes explicit the consideration of Transport, Establishment, Abundance, Spread and Impact aspects of biological invasions helps integrate the main ideas underlying risk assessment and identifies important open questions. Barry (2013) provided a thoughtful review of our study and while he found much to commend in our approach, he indicated two main criticisms: (1) the mapping process in the article was subjective and TEASI does not encapsulate all the reviewed RAs and (2) we are not explicit in defining the best practice. We address each criticism. First, although quantitative approaches were relatively easy to map onto the TEASI framework, scoring-based approaches were more difficult and more subjective. Importantly, subjective does not mean arbitrary. For instance, mapping RA questions such as 'propa-gules dispersed by wind' onto the Spread component in TEASI and identifying it as a species trait is arguably logical. However, the rationale for how answers were combined was less clear for scoring approaches. For instance, many simply summed binary yes/no answers across all components, so we agree that they 'would need to be radically redefined' to map onto TEASI as many do not consider model structure. Barry (2013) further notes that the scoring approaches 'are abstract while the TEASI model is process-based and explicit'. This is certainly true but if the 'abstract' risks do not (at least imperfectly) map onto the set of real processes underlying invasions, we question whether they can be predictive. Thus, we argue that scoring-based approaches can and should be considered in the context of a process-based framework, but we acknowledge that this is challenging. We view this difficulty in mapping model structure as a limitation of existing scoring methodology rather than of the process-based TEASI model. We pose the questions: do the scoring model structures make sense in terms of invasion processes? How? If they do not, in the future, should they? Note, we do not deny the value of scoring RAs; they will remain important in addressing biological invasions, given limited time, data and resources. In addition, Barry (2013) argues that TEASI equations were too highly structured and prescriptive. Although we could have just listed factors thought to be relevant for invasion risk, this would be less valuable. Models are useful, in part, exactly because they are highly structured, presenting a clear picture of how we believe factors rel...
The equilibrium theory of island biogeography is the basis for estimating extinction rates and a pillar of conservation science. The default strategy for conserving biodiversity is the designation of nature reserves, treated as islands in an inhospitable sea of human activity. Despite the profound influence of islands on conservation theory and practice, their mainland analogues, forest fragments in human-dominated landscapes, consistently defy expected biodiversity patterns based on island biogeography theory. Countryside biogeography is an alternative framework, which recognizes that the fate of the world's wildlife will be decided largely by the hospitality of agricultural or countryside ecosystems. Here we directly test these biogeographic theories by comparing a Neotropical countryside ecosystem with a nearby island ecosystem, and show that each supports similar bat biodiversity in fundamentally different ways. The island ecosystem conforms to island biogeographic predictions of bat species loss, in which the water matrix is not habitat. In contrast, the countryside ecosystem has high species richness and evenness across forest reserves and smaller forest fragments. Relative to forest reserves and fragments, deforested countryside habitat supports a less species-rich, yet equally even, bat assemblage. Moreover, the bat assemblage associated with deforested habitat is compositionally novel because of predictable changes in abundances by many species using human-made habitat. Finally, we perform a global meta-analysis of bat biogeographic studies, spanning more than 700 species. It generalizes our findings, showing that separate biogeographic theories for countryside and island ecosystems are necessary. A theory of countryside biogeography is essential to conservation strategy in the agricultural ecosystems that comprise roughly half of the global land surface and are likely to increase even further.
Peer reviewed eScholarship.orgPowered by the California Digital Library University of California of committing a moral act later (Fig. 4). In addition, a moral self-licensing pattern emerged (18), such that committing a moral act earlier in the day was associated with an above-average likelihood of a subsequent immoral act and a decreased likelihood of a subsequent moral act (Fig. 4). Together, the analysis of everyday moral dynamics revealed evidence both for moral contagion through other people's good deeds and moral self-licensing through one's own good deeds outside of the laboratory. Given these different mechanisms, it seems important to find out more about how the principles of moral contagion can be used in public policy interventions, and how moral slacking may be prevented. By tracking people's everyday moral experiences, we corroborated well-controlled but artificial laboratory research, refined prior predictions, and made illuminating discoveries about how people experience and structure morality, as well as about how morality affects people's happiness and sense of purpose. A closer, ecologically valid look at how morality unfolds in people's natural environments may inspire new models and theories about what it means to lead the "good" or "bad" life. Psychol. 4, 1-32 (2008). 12. J. Graham et al., J. Pers. Soc. Psychol. 101, 366-385 (2011). 13. J. Haidt, J. Graham, Soc. Justice Res. 20, 98-116 (2007. 14. J. Graham et al., Adv. Exp. Soc. Psychol. 47, 55-130 (2013 Habitat conversion is the primary driver of biodiversity loss, yet little is known about how it is restructuring the tree of life by favoring some lineages over others. We combined a complete avian phylogeny with 12 years of Costa Rican bird surveys (118,127 detections across 487 species) sampled in three land uses: forest reserves, diversified agricultural systems, and intensive monocultures. Diversified agricultural systems supported 600 million more years of evolutionary history than intensive monocultures but 300 million fewer years than forests. Compared with species with many extant relatives, evolutionarily distinct species were extirpated at higher rates in both diversified and intensive agricultural systems. Forests are therefore essential for maintaining diversity across the tree of life, but diversified agricultural systems may help buffer against extreme loss of phylogenetic diversity.A s human-converted habitats expand over Earth's surface, the fate of global biodiversity will depend increasingly on the quality and characteristics of farming landscapes (1, 2). Agricultural systems vary widely in their ability to support biodiversity, with many species extirpated from some but sustained in others (1, 3). Additionally, characteristics of the species themselves, evolved over millions of years, may predispose some lineages to benefit (or suffer) from human environmental impacts (4-6).Phylogenetic diversity, the total evolutionary history or phylogenetic branch lengths of all species in a community (7), is recognized as having intr...
Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change.
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