Search

With large wildfires becoming more frequent 1,2 , we must rapidly learn how megafires impact biodiversity to prioritize mitigation and improve policy. A key challenge is to discover how interactions among fire-regime components, drought and land tenure shape wildfire impacts. The globally unprecedented 3,4 2019-2020 Australian megafires burnt more than 10 million hectares 5 , prompting major investment in biodiversity monitoring. Collated data include responses of more than 2,000 taxa, providing an unparalleled opportunity to quantify how megafires affect biodiversity. We reveal that the largest effects on plants and animals were in areas with frequent or recent past fires and within extensively burnt areas. Areas burnt at high severity, outside protected areas or under extreme drought also had larger effects. The effects included declines and increases after fire, with the largest responses in rainforests and by mammals. Our results implicate species interactions, dispersal and extent of in situ survival as mechanisms underlying fire responses. Building wildfire resilience into these ecosystems depends on reducing fire recurrence, including with rapid wildfire suppression in areas frequently burnt. Defending wet ecosystems, expanding protected areas and considering localized drought could also contribute. While these countermeasures can help mitigate the impacts of more frequent megafires, reversing anthropogenic climate change remains the urgent broad-scale solution., Competing Interests: Competing interests The authors declare that some of them work for government agencies involved in forestry and implementing planned burns (Supplementary Table 8). The lead author declares that, despite the potential for government agencies to impose policy positions on staff communications (see ref. 51), scientific independence and integrity has been maintained throughout this project., (© 2024. The Author(s).)

Noncoding DNA is central to our understanding of human gene regulation and complex diseases 1,2 , and measuring the evolutionary sequence constraint can establish the functional relevance of putative regulatory elements in the human genome 3-9 . Identifying the genomic elements that have become constrained specifically in primates has been hampered by the faster evolution of noncoding DNA compared to protein-coding DNA 10 , the relatively short timescales separating primate species 11 , and the previously limited availability of whole-genome sequences 12 . Here we construct a whole-genome alignment of 239 species, representing nearly half of all extant species in the primate order. Using this resource, we identified human regulatory elements that are under selective constraint across primates and other mammals at a 5% false discovery rate. We detected 111,318 DNase I hypersensitivity sites and 267,410 transcription factor binding sites that are constrained specifically in primates but not across other placental mammals and validate their cis-regulatory effects on gene expression. These regulatory elements are enriched for human genetic variants that affect gene expression and complex traits and diseases. Our results highlight the important role of recent evolution in regulatory sequence elements differentiating primates, including humans, from other placental mammals., (© 2023. The Author(s).)

Global wildlife trade is a multibillion-dollar industry and a significant driver of vertebrate extinction risk. Yet, few studies have quantified the impact of wild harvesting for the illicit pet trade on populations. Long-lived species, by virtue of their slow life history characteristics, may be unable to sustain even low levels of collecting. Here, we assessed the impact of illegal collecting on populations of endangered broad-headed snakes (Hoplocephalus bungaroides) at gated (protected) and ungated (unprotected) sites. Because broad-headed snakes are long-lived, grow slowly and reproduce infrequently, populations are likely vulnerable to increases in adult mortality. Long-term data revealed that annual survival rates of snakes were significantly lower in the ungated population than the gated population, consistent with the hypothesis of human removal of snakes for the pet trade. Population viability analysis showed that the ungated population has a strongly negative population growth rate and is only prevented from ultimate extinction by dispersal of small numbers of individuals from the gated population. Sensitivity analyses showed that the removal of a small number of adult females was sufficient to impose negative population growth and suggests that threatened species with slow life histories are likely to be especially vulnerable to illegal collecting.

The ubiquitous intracellular protease dipeptidyl peptidase 9 (DPP9) has roles in antigen presentation and B cell signaling. To investigate the importance of DPP9 in immune regeneration, primary and secondary chimeric mice were created in irradiated recipients using fetal liver cells and adult bone marrow cells, respectively, using wild-type (WT) and DPP9 gene-knockin (DPP9 S729A ) enzyme-inactive mice. Immune cell reconstitution was assessed at 6 and 16 weeks post-transplant. Primary chimeric mice successfully regenerated neutrophils, natural killer, T and B cells, irrespective of donor cell genotype. There were no significant differences in total myeloid cell or neutrophil numbers between DPP9-WT and DPP9 S729A -reconstituted mice. In secondary chimeric mice, cells of DPP9 S729A -origin cells displayed enhanced engraftment compared to WT. However, we observed no differences in myeloid or lymphoid lineage reconstitution between WT and DPP9 S729A donors, indicating that hematopoietic stem cell (HSC) engraftment and self-renewal is not diminished by the absence of DPP9 enzymatic activity. This is the first report on transplantation of bone marrow cells that lack DPP9 enzymatic activity.

The article reports monoaminergic metabolite [homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-4-hydroxyphenylglycol (MHPG)], values from the cerebrospinal fluid (CSF) of 27 wild baboons (Papio hamadryas) aged 40 to 140 months. Animals were either anubis, or anubis with hamadryas admixture; males of the latter subspecies generally have a reduced tendency to disperse from their natal groups. Overall, the values and interrelationships among the CSF monoamine metabolites resembled data reported from closely related, captive-housed animals. For example, age was significantly correlated with HVA concentrations (r = -60, p < .05), but not with the other metabolites. Notably, males characterized by hamadryas admixture had significantly higher concentrations of HVA, 5-HIAA, and MHPG (p < .05, respectively), a result possibly driven by differences in serotonergic activity. These data provide initial evidence that variation in central monoaminergic activity, as indicated by CSF monoamine metabolite concentrations, may reflect differences in behavior and life history that have taxonomic and, perhaps, evolutionary significance.

A review of fossil mammalian faunas from the Middle Awash indicates they span most of the later Neogene and document evolutionary change in several mammalian groups, especially Primates, Proboscidea and Artiodactyla. Oldowan artefacts first appear in the late Pliocene, while Acheulian and later industries and apparent occupation sites occur in Pleistocene beds.