Reimagining the relationship between Gondwanan forests and Aboriginal land management in Australia's "Wet Tropics"

Paleobotany reframes the fiery debate on Australia's rainforest edges

The tall eucalypt forests (TEFs) of the Australian tropics are often portrayed as threatened by 'invasive' neighboring rainforests, requiring 'protective' burning. This framing overlooks that Australian rainforests have suffered twice the historical losses of TEFs and ignores the ecological and paleobiological significance of rainforest margins. Early Eocene fossils from Argentina show that biodiverse rainforests with abundant Eucalyptus existed > 50 million years ago (Ma) in West Gondwana, shaped by nonfire disturbance factors such as landslides and volcanic flows. Humid volcanic environments with eucalypts were also present in eastern Australia over much of the Cenozoic. The dominance of fire-adapted eucalypts appears to be geologically recent and is linked to Neogene C4 grassland expansion, Pleistocene climate cycles, and human activity. We suggest that characterizing TEFs and rainforests as adversarial results from misinterpreting the evolutionary history and expansion-contraction dynamics of a single humid forest system, whose features are now heavily modified by human activities. The resulting management practices damage the outstanding World Heritage values and carbon storage of affected areas and thus have impacts far beyond Australia. The fossil evidence shows that rainforest margins preserve ancient, still evolving, and globally significant forest interactions that should be prioritized for restoration and research.

More than dirt: Sedimentary ancient DNA and Indigenous Australia

The rise of sedimentary ancient DNA (sedaDNA) studies has opened new possibilities for studying past environments. This groundbreaking area of genomics uses sediments to identify organisms, even in cases where macroscopic remains no longer exist. Managing this substrate in Indigenous Australian contexts, however, requires special considerations. Sediments and soils are often considered as waste by-products during archaeological and paleontological excavations and are not typically regulated by the same ethics guidelines utilised in mainstream 'western' research paradigms. Nevertheless, the product of sedaDNA work-genetic information from past fauna, flora, microbial communities and human ancestors-is likely to be of cultural significance and value for Indigenous peoples. This article offers an opinion on the responsibilities of researchers in Australia who engage in research related to this emerging field, particularly when it involves Indigenous communities. One aspect that deserves consideration in such research is the concept of benefit sharing. Benefit sharing refers to the practice of ensuring that the benefits that arise from research are shared equitably with the communities from which the research data were derived. This practice is particularly relevant in research that involves Indigenous communities, who may have unique cultural and spiritual connections to the research material. We argue that the integration of Traditional Knowledges into sedaDNA research would add enormous value to research and its outcomes by providing genomic outputs alongside and within the rich context of multimillennia oral histories.

Landscape burning facilitated Aboriginal migration into Lutruwita/Tasmania 41,600 years ago

The establishment of Tasmanian Palawa/Pakana communities ~40 thousand years ago (ka) was achieved by the earliest and farthest human migrations from Africa and necessitated migration into high-latitude Southern Hemisphere environments. The scarcity of high-resolution paleoecological records during this period, however, limits our understanding of the environmental effects of this pivotal event, particularly the importance of using fire as a tool for habitat modification. We use two paleoecological records from the Bass Strait islands to identify the initiation of anthropogenic landscape transformation associated with ancestral Palawa/Pakana land use. People were living on the Tasmanian/Lutruwitan peninsula by ~41.6 ka using fire to penetrate and manipulate forests, an approach possibly used in the first migrations across the last glacial landscape of Sahul.

Human interactions with tropical environments over the last 14,000 years at Iho Eleru, Nigeria

The Ihò Eléérú (or Iho Eleru) rock shelter, located in Southwest Nigeria, is the only site from which Pleistocene-age hominin fossils have been recovered in western Africa. Excavations at Iho Eleru revealed regular human occupations ranging from the Later Stone Age (LSA) to the present day. Here, we present chronometric, archaeobotanical, and paleoenvironmental findings, which include the taxonomic, taphonomic, and isotopic analyses of what is the only Pleistocene faunal assemblage documented in western Africa. Our results indicate that the local landscape surrounding Iho Eleru, although situated within a regional open-canopy biome, was forested throughout the past human occupation of the site. At a regional scale, a shift from forest- to savanna-dominated ecotonal environment occurred during a mid-Holocene warm event 6,000 years ago, with a subsequent modern reforestation of the landscape. Locally, no environmental shift was observable, placing Iho Eleru in a persistent forested "island" during the period of occupation.

Laying low: Rugged lowland rainforest preferred by feral cats in the Australian Wet Tropics

Invasive mesopredators are responsible for the decline of many species of native mammals worldwide. Feral cats have been causally linked to multiple extinctions of Australian mammals since European colonization. While feral cats are found throughout Australia, most research has been undertaken in arid habitats, thus there is a limited understanding of feral cat distribution, abundance, and ecology in Australian tropical rainforests. We carried out camera-trapping surveys at 108 locations across seven study sites, spanning 200 km in the Australian Wet Tropics. Single-species occupancy analysis was implemented to investigate how environmental factors influence feral cat distribution. Feral cats were detected at a rate of 5.09 photographs/100 days, 11 times higher than previously recorded in the Australian Wet Tropics. The main environmental factors influencing feral cat occupancy were a positive association with terrain ruggedness, a negative association with elevation, and a higher affinity for rainforest than eucalypt forest. These findings were consistent with other studies on feral cat ecology but differed from similar surveys in Australia. Increasingly harsh and consistently wet weather conditions at higher elevations, and improved shelter in topographically complex habitats may drive cat preference for lowland rainforest. Feral cats were positively associated with roads, supporting the theory that roads facilitate access and colonization of feral cats within more remote parts of the rainforest. Higher elevation rainforests with no roads could act as refugia for native prey species within the critical weight range. Regular monitoring of existing roads should be implemented to monitor feral cats, and new linear infrastructure should be limited to prevent encroachment into these areas. This is pertinent as climate change modeling suggests that habitats at higher elevations will become similar to lower elevations, potentially making the environment more suitable for feral cat populations.

Indigenous oyster fisheries persisted for millennia and should inform future management

Historical ecology has revolutionized our understanding of fisheries and cultural landscapes, demonstrating the value of historical data for evaluating the past, present, and future of Earth’s ecosystems. Despite several important studies, Indigenous fisheries generally receive less attention from scholars and managers than the 17th–20th century capitalist commercial fisheries that decimated many keystone species, including oysters. We investigate Indigenous oyster harvest through time in North America and Australia, placing these data in the context of sea level histories and historical catch records. Indigenous oyster fisheries were pervasive across space and through time, persisting for 5000–10,000 years or more. Oysters were likely managed and sometimes “farmed,” and are woven into broader cultural, ritual, and social traditions. Effective stewardship of oyster reefs and other marine fisheries around the world must center Indigenous histories and include Indigenous community members to co-develop more inclusive, just, and successful strategies for restoration, harvest, and management.

‘Commercial fisheries have decimated keystone species, including oysters in the past 200 years. Here, the authors examine how Indigenous oyster harvest in North America and Australia was managed across 10,000 years, advocating for effective future stewardship of oyster reefs by centering Indigenous peoples.’

Tropical fruits from Australia as potential treatments for metabolic syndrome

Australia has a unique and diverse flora, including indigenous fruits, used by Australian Aboriginals for food and medicines for up to 45,000 years as well as recently introduced fruits for commercial production. However, this range of fruits has not led to the development of functional foods, for example for chronic inflammatory diseases such as metabolic syndrome including obesity, hypertension, fatty liver and diabetes. This review examines the potential of tropical and subtropical fruits from Australia to be used as functional foods for metabolic syndrome, including Davidson's plum, Queen Garnet plum, durian, litchi, breadfruit, jackfruit, mangosteen, papaya, jabuticaba, coffee and seaweed. Preclinical studies have defined potential responses of these functional foods in metabolic syndrome but the usefulness in humans with metabolic syndrome requires clinical studies which are scarce in the relevant literature. Overall, these Australian examples show that tropical fruits can provide functional foods to decrease chronic inflammatory diseases.

Landscape modification by Last Interglacial Neanderthals

Little is known about the antiquity, nature, and scale of Pleistocene hunter-gatherer impact on their ecosystems, despite the importance for studies of conservation and human evolution. Such impact is likely to be limited, mainly because of low population densities, and challenging to detect and interpret in terms of cause-effect dynamics. We present high-resolution paleoenvironmental and archaeological data from the Last Interglacial locality of Neumark-Nord (Germany). Among the factors that shaped vegetation structure and succession in this lake landscape, we identify a distinct ecological footprint of hominin activities, including fire use. We compare these data with evidence from archaeological and baseline sites from the same region. At Neumark-Nord, notably open vegetation coincides with a virtually continuous c. 2000-year-long hominin presence, and the comparative data strongly suggest that hominins were a contributing factor. With an age of c. 125,000 years, Neumark-Nord provides an early example of a hominin role in vegetation transformation.

Late Pleistocene/Early Holocene sites in the montane forests of New Guinea yield early record of cassowary hunting and egg harvesting

How early human foragers impacted insular forests is a topic with implications across multiple disciplines, including resource management. Paradoxically, terminal Pleistocene and Early Holocene impacts of foraging communities have been characterized as both extreme-as in debates over human-driven faunal extinctions-and minimal compared to later landscape transformations by farmers and herders. We investigated how rainforest hunter-gatherers managed resources in montane New Guinea and present some of the earliest documentation of Late Pleistocene through mid-Holocene exploitation of cassowaries (Aves: Casuariidae). Worldwide, most insular ratites were extirpated by the Late Holocene, following human arrivals, including elephant birds of Madagascar (Aepyornithidae) and moa of Aotearoa/New Zealand (Dinornithiformes)-icons of anthropogenic island devastation. Cassowaries are exceptional, however, with populations persisting in New Guinea and Australia. Little is known of past human exploitation and what factors contributed to their survival. We present a method for inferring past human interaction with mega-avifauna via analysis of microstructural features of archaeological eggshell. We then contextualize cassowary hunting and egg harvesting by montane foragers and discuss the implications of human exploitation. Our data suggest cassowary egg harvesting may have been more common than the harvesting of adults. Furthermore, our analysis of cassowary eggshell microstructural variation reveals a distinct pattern of harvesting eggs in late ontogenetic stages. Harvesting eggs in later stages of embryonic growth may reflect human dietary preferences and foraging seasonality, but the observed pattern also supports the possibility that-as early as the Late Pleistocene-people were collecting eggs in order to hatch and rear cassowary chicks.

Indigenous knowledge and the shackles of wilderness

The environmental crises currently gripping the Earth have been codified in a new proposed geological epoch: the Anthropocene. This epoch, according to the Anthropocene Working Group, began in the mid-20th century and reflects the "great acceleration" that began with industrialization in Europe [J. Zalasiewicz et al., Anthropocene 19, 55-60 (2017)]. Ironically, European ideals of protecting a pristine "wilderness," free from the damaging role of humans, is still often heralded as the antidote to this human-induced crisis [J. E. M. Watson et al., Nature, 563, 27-30 (2018)]. Despite decades of critical engagement by Indigenous and non-Indigenous observers, large international nongovernmental organizations, philanthropists, global institutions, and nation-states continue to uphold the notion of pristine landscapes as wilderness in conservation ideals and practices. In doing so, dominant global conservation policy and public perceptions still fail to recognize that Indigenous and local peoples have long valued, used, and shaped "high-value" biodiverse landscapes. Moreover, the exclusion of people from many of these places under the guise of wilderness protection has degraded their ecological condition and is hastening the demise of a number of highly valued systems. Rather than denying Indigenous and local peoples' agency, access rights, and knowledge in conserving their territories, we draw upon a series of case studies to argue that wilderness is an inappropriate and dehumanizing construct, and that Indigenous and community conservation areas must be legally recognized and supported to enable socially just, empowering, and sustainable conservation across scale.

Adaptive Heritage: Is This Creative Thinking or Abandoning Our Values?

Protected areas, such as natural World Heritage sites, RAMSAR wetlands and Biosphere Reserves, are ecosystems within landscapes. Each site meets certain criteria that allow it to qualify as a heritage or protected area. Both climate change and human influence (e.g., incursion, increased tourist visitation) are altering biophysical conditions at many such sites. As a result, conditions at many sites are falling outside the criteria for their original designation. The alternatives are to change the criteria, remove protection from the site, change site boundaries such that the larger or smaller landscape meets the criteria, or manage the existing landscape in some way that reduces the threat. This paper argues for adaptive heritage, an approach that explicitly recognizes changing conditions and societal value. We discuss the need to view heritage areas as parts of a larger landscape, and to take an adaptive approach to the management of that landscape. We offer five themes of adaptive heritage: (1) treat sites as living heritage, (2) employ innovative governance, (3) embrace transparency and accountability, (4) invest in monitoring and evaluation, and (5) manage adaptively. We offer the Australian Wet Tropics as an example where aspects of adaptive heritage currently are practiced, highlighting the tools being used. This paper offers guidance supporting decisions about natural heritage in the face of climate change and non-climatic pressures. Rather than delisting or lowering standards, we argue for adaptive approaches.