Just metamorphosed amphibians: imagos or metamorphs?

The term metamorph for just metamorphosed amphibians appeared surreptitiously in the batrachological literature. It is shown here that this term is linguistically unjustified and conceptually confusing, as it has never been associated with a clear, formal definition stating in particular when does this developmental stage start and end. The use of the term imago for an individual resulting from the last metamorphosis following a larval stage, which exists for insects since 1767 and for amphibians since 1808, is much preferable. For amphibians, the formal definition of this term was given in 1978 as an animal having completed its metamorphosis, before having substantially grown and until the first major ecological event in its life cycle (such as migration, hibernation or aestivation). In amphibians, this stage is followed by a stage juvenile and a stage subadult until the stage adult is reached, which is defined by sexual maturity and ability to reproduce. Given the diversity of developmental modes in the animal kingdom, it would be vain to try to homogenise the terminology of all detailed developmental stages across all groups. However, the possibility to homogenise the use of the term imago throughout zoology for specimens resulting from the ‘last metamorphosis’ (i.e., drastic change not only of form but also in some anatomical structures), whether followed by growth and minor transformations or not, and whether associated with sexual maturity or not, would certainly be worth considering. This would allow to have a few general descriptive terms to designate the main similar, but not homologous, ‘landmarks’ observed in the development of many animals (egg, larva, imago and adult), just like we have a general term (metamorphosis) for ‘similar’ phenomena which are not homologous. This would not prevent specialists of the various zoological groups to have specific terms for more precisely defined ‘stages’ which are proper to these groups.

Is the Anthropause a useful symbol and metaphor for raising environmental awareness and promoting reform?

Summary Lockdowns associated with the COVID-19 pandemic temporarily restricted human activity and removed people from many places of work and recreation. The resulting ‘Anthropause’ generated much media and research interest and has become an important storyline in the public history of the pandemic. As an ecological event, the Anthropause is fleeting and unlikely to alter the long-term human impact on the planet. But the Anthropause is also a cultural symbol whose effects may be more enduring. Will the Anthropause inspire people and governments to mobilize for meaningful reform, or does it present a misleading and too-comforting portrayal of resilient nature and wildlife that could ultimately discourage action? While it is too early to gauge the impact of the Anthropause on human behaviour and politics, we use existing research on environmental symbols and metaphors to identify factors that may influence long-term behavioural and political responses to this globally significant period of time.

More than the Mud March

This chapter discusses the rationale and blueprint for the book, explaining how the authors combine the methodologies of environmental and military history to tell a more holistic story of the Civil War. It begins with an analysis of Burnside’s Mud March in January 1863, and uses that campaign to demonstrate how to merge these two disciplines into a deeper analysis of the war. The authors demonstrate how examining the war as an ecological event allows for a more complete and comprehensive understanding of the conflict.

Accelerating Change

Emancipation proved to be a far-reaching ecological event. Whereas the ecological regime of slavery had reinforced extensive land-use practices, the end of slavery weakened them. Freedpeople dedicated less time to erosion control and ditching and used contract negotiations and sharecropping arrangements to avoid working in a centrally directed gang. Understandably, freedpeople preferred to direct their own labor on an individual plot of land. The eventual proliferation of share-based or tenant contracts encouraged the physical reorganization of plantations. The combination of these two progressive alterations to labor relations tragically undermined African Americans’ efforts to achieve economic independence by tightening natural limits on cotton production and reducing blacks’ access to the South’s internal provisioning economy. The cessation, or even reduced frequency, of land maintenance on farms exacerbated erosion, flooding, and crops’ susceptibility to drought.

On the accuracy of paleodiversity reconstructions: a case study in Antarctic Neogene radiolarians

The deep-sea Cenozoic planktonic microfossil record has the unique characteristics of continuously well-preserved populations of most species, with virtually unlimited sample size, and therefore constitutes, in principle, a major resource for macroevolutionary research. Antarctic Neogene radiolarians in particular, are diverse, abundant and consistently well-preserved and evolved rapidly. This fauna is, in theory, a near-perfect testing ground for paleodiversity reconstructions. In this study we determined the diversity history of these faunas from a new quantitative, taxonomically complete data set from Neogene and Quaternary sections at several Antarctic sites. The pattern retrieved by our whole-fauna data set shows a significant, largely extinctionless ecological change in faunal composition and decrease in the evenness of species' abundances during the late Miocene, followed 3 Myr later, at around 5 Ma, by a significant drop in diversity. We tentatively associate this ecological event with a synchronous, regional change in the composition of the primary producers, but as yet cannot identify any environmental changes associated with the later extinction. Further, our whole-fauna diversity history was compared to diversity computed from much less complete, biostratigraphically oriented studies of species' occurrences, compiled in the Neptune database and reconstructed by using subsampling methodologies. Comparison of our whole-fauna and subsampling-reconstructed diversity patterns shows that the first-order trends are the same in both, suggesting that, to some degree, such literature compilations can be used to explore diversity history of plankton. However, our results also highlight substantial errors and distortions in the reconstructed diversity which make it poorly suited to more-detailed studies (e.g., for comparison of diversity history with paleoenvironmental history). We conclude that detailed studies of plankton diversity, and particularly those attempting to understand the relation between diversity and paleoceanographic change, should be based on taxonomically comprehensive, quantitative data.

Severe red spruce winter injury in 2003 creates unusual ecological event in the northeastern United States

Abundant winter injury to the current-year (2002) foliage of red spruce (Picea rubens Sarg.) became apparent in the northeastern United States in late winter of 2003. To assess the severity and extent of this damage, we measured foliar winter injury at 28 locations in Vermont and surrounding states and bud mortality at a subset of these sites. Ninety percent of all trees assessed showed some winter injury, and trees lost an average of 46% of all current-year foliage. An average of 32% of buds formed in 2002 were killed in association with winter injury. Both foliar and bud mortality increased with elevation and with crown dominance, and bud mortality increased with greater foliar injury. Foliar injury in 2003 at a plantation near Colebrook, New Hampshire, was more than five times the typical levels for 9 previous years of measurement and more than twice that measured for another high-injury year. Plantation data also indicated that bud mortality in 2003 was greater than previously documented and that persistent winter injury was associated with increased tree mortality. Comparisons of our data with past studies for two sites with native red spruce also indicated that damage in 2003 was greater than other recently reported, high-injury years. Because heavy foliar and bud losses can severely disrupt the carbon economies of trees, the 2003 winter injury event could lead to further spruce decline and mortality, particularly among dominant trees at higher elevations.