Conserving Earth’s ecosystems is critical for sustaining human life, yet some aspects of living nature can harm people, such as insect vectors of human disease and venomous animals. Nature’s contributions to people (NCPs) that cause harm are a contentious issue in biodiversity research and policy, with limited agreement on how they should be assessed or managed. We therefore propose a new conceptual framework for assessing and managing harmful NCPs that draws parallels with the Intergovernmental Panel on Climate Change’s concept of climate risk. We argue that the risks of harmful NCPs should be understood as arising from the intersection of the hazardous aspects of ecosystems (ecosystem hazards) with societal exposure and vulnerability. Our risk-based approach equips decision-makers with a framework to systematically identify solutions for avoiding societal harms, while preventing maladaptive interventions that can undermine sustainability goals and degrade ecosystems. We conclude by outlining priority next steps for operationalizing our framework. Some aspects of nature can be harmful to people and have become contentious issues in biodiversity research and policy. This Perspective proposes a new conceptual framework for assessing and managing nature’s harmful contributions to people, drawing parallels with the concept of climate risk.
The renowned tropical flora of Southeast Asia is often regarded as being of relatively recent (Cenozoic) origin. Here, based on specimens embedded in mid-Cretaceous amber obtained from Kachin, Myanmar, we report on a large assemblage of exceptionally well-preserved plant fossils encompassing a rich diversity of angiosperms, together with many other seed plants and cryptogams. The morphospecies richness and clade diversity of this flora are among the highest recorded for any single Early to mid-Cretaceous plant megafossil assemblage. This ancient flora reached Southeast Asia rafted on the West Burma Block, an arc-shaped microplate that separated from the northwestern corner of the Australian Plate during the Jurassic and drifted north, finally colliding with Sundaland by the Eocene. The Burma Terrane remained low lying and at low latitudes in the intervening 100–50-million-year period, providing a sanctuary for clade preservation, a cradle for modern clade diversification and a conduit for transferring flourishing Gondwanan angiosperm lineages to Asia. These findings provide insight into the cradle of what ultimately became Southeast Asian angiosperm-dominated tropical forests, whose origins date back over 100 million years. Here the authors present an assemblage of plant fossils three-dimensionally preserved in amber, including 392 angiosperm morphospecies and 152 non-angiosperm morphospecies represented by flowers, fruit, leaves and other plant parts. This assemblage documents exceptionally diverse flora in the mid-Cretaceous.
Each year, migratory birds move thousands of kilometres across international borders to track optimal environmental conditions. How tightly annual-cycle events are linked and how much flexibility exists in migration schedules will determine how vulnerable migratory birds are to environmental change. Using a global tracking database, we reconstructed full annual-cycle schedules of 2,324 individuals from 83 species. We found strong temporal links during autumn and spring migrations: departure from the breeding grounds predicted arrival at the non-breeding grounds and vice versa. During both migration periods, late-departing individuals shortened migration duration, but still arrived later than early-departing individuals. By contrast, arrival at and departure from the non-breeding grounds were not correlated, suggesting a temporal reset that buffered earlier delays. Despite resetting during the non-breeding period, migratory schedules remain globally interconnected, such that disruptions in one season can propagate to subsequent stages of the annual cycle, with consequences for migratory species and the ecosystem functions they support. Analysing the complete annual life cycle from tracking data among 83 species of migratory landbirds across six continents, the authors identify strong temporal links in schedules of migratory periods but a temporal reset during the extended non-breeding period.
The coevolution of interacting mitochondrial and nuclear genes is increasingly recognized as a critical component of organismal fitness and a potential source of genetic incompatibilities that promote speciation. In species with ‘ZW’ sex chromosomes, however, selection on maternally inherited traits may impact mitonuclear coevolution owing to the effective linkage of the W chromosome and mitochondrial DNA (mtDNA). Here we show that in brood parasitic cuckoo finches (Anomalospiza imberbis), enhanced ecological selection on a maternally inherited trait (mimetic egg colouration) subjects both the W chromosome and mtDNA to increased accumulation of slightly deleterious mutations via genetic hitchhiking, accelerating W chromosome pseudogenization and gene loss, as well as mitonuclear coevolution. Remarkably, as other W-linked genes were lost, two egg colour genes, representing likely targets of selection during cuckoo finch–host coevolution, were recruited to the W chromosome. Using structural models of the respiratory complexes and mitoribosome, we also show that the rate of amino acid substitution in nuclear-encoded residues is a function of their proximity to mtDNA-encoded residues, providing evidence of compensatory mitonuclear coevolution. Our results link species-level coevolution to both sex chromosome degeneration and mitonuclear coevolution. More generally, they highlight the genomic consequences of adaptation without recombination. Comparative genomics across eight songbird species links strong ecological selection on maternally inherited egg colour phenotypes to both accelerated W chromosome degeneration and mitonuclear coevolution in the brood parasitic cuckoo finch (Anomalospiza imberbis), reflecting the consequences of genetic hitchhiking for non-recombining components of the genome.
