Hong Kong is one of the busiest metropolises, and the Eurasian otter Lutra lutra is one of its most threatened species. We collected published data for 1890–2020 to document changes in local otter abundance and distribution over time. The 108 records revealed new distribution data and showed that decline began as early as the 1930s. The local Eurasian otter is strongly associated with coastal and alluvial wetlands, and its last refugium, the Yuen Long floodplain draining the Mai Po Inner Deep Bay Ramsar Site, has always been a critical habitat. Our analysis suggests that hunting is unlikely to be a major cause of the otter's decline. Rather, dependence on lowland wetlands makes it particularly susceptible to habitat loss caused by increasing urbanization. Auxiliary infrastructures and water pollution have also exacerbated wetland degradation to the detriment of otters and their prey. There is a need for greater cooperation amongst government agencies and landowners to guarantee otter survival: priority steps include the establishment of additional and interconnected wetland reserves, better stakeholder engagement and enforcement efficiency to tackle entrenched pollution problems, and flood prevention schemes that preserve or restore functional riverine ecosystems within critical otter habitats. The current otter distribution range has been earmarked for development in a government-led mega urbanization plan; the plight of the local Eurasian otter needs to be widely publicized to garner stakeholders' support and galvanize immediate conservation actions across society.

The Napo River basin, which is situated within the Upper Amazon archaeological region, is one of the most speciose forests in Greater Amazonia. Standard thinking in scholarship and science holds that these forests are essentially pristine because any Indigenous impacts in the past would have been minimal, seedbanks would have been nearby, and natural forests would have reappeared after the humans left, died out, or dispersed. Inventory research in 2019 on three ridgetop forests in Waorani territory inside the Curaray basin (which drains to the right margin of the Napo River) and a comparable inventory on one control site forest along the Nushiño River (also in the Curaray basin) show human impacts from about the late nineteenth century to about 1960; they occurred during the period of wartime among Waorani themselves and between Wao people and outsiders. The human impacts resulted in the high basal-area presence of two long-lived species with important Waorani cultural uses: cacao (Theobroma cacao L.) and ungurahua palm (Oenocarpus bataua Mart.). These species have high frequency and dominance values and do not occur in the control site, which is comparable in terms of elevation above the flood zone of the rivers in the sample. These findings mean that alpha diversity in the right margin sector (or south) of the Napo River basin cannot a priori be explained by reference to traditionally, biologically accepted patterns of ecological succession but may require knowledge of historical patterns of Indigenous land use and secondary landscape transformation over time due to human (specifically Waorani) impacts of the past.

Many of the most contentious questions that concern the ecology of helminths could be resolved with data on helminth abundance over the past few decades or centuries, but unfortunately these data are rare. A new sub-discipline – the historical ecology of parasitism – is resurrecting long-term data on the abundance of parasites, an advancement facilitated by the use of biological natural history collections. Because the world's museums hold billions of suitable specimens collected over more than a century, these potential parasitological datasets are broad in scope and finely resolved in taxonomic, temporal and spatial dimensions. Here, we set out best practices for the extraction of parasitological information from natural history collections, including how to conceive of a project, how to select specimens, how to engage curators and receive permission for proposed projects, standard operating protocols for dissections and how to manage data. Our hope is that other helminthologists will use this paper as a reference to expand their own research programmes along the dimension of time.

The places in which people live and spend time are steeped in history, memory, and meaning from the intersection of daily life, environmental interactions, cultural practices, and ritual. Geologic features, plants, animals, and ecosystems merge with these cultural histories, forming critical parts of the landscape and areas of “high cultural salience,” or “cultural keystone places” (CKPs). We identify Kumqaq’ (Point Conception) and the surrounding area in California as a Chumash CKP. Ethnohistoric accounts and contemporary Chumash community members have long demonstrated the importance of Point Conception in Chumash worldview and identity, whereas biologists, ecologists, and conservationists reference the area's rich biodiversity and significance as a biogeographical boundary. Recent archaeological survey of the coastline surrounding Kumqaq’ highlights these connections, identifying over 50 archaeological sites—including shell middens, villages, lithic scatters, and rock art—with at least 9,000 years of occupation. Ongoing collaborations among archaeologists, the Nature Conservancy, and Chumash community members help document and understand the long-term linkages between cultural and biological diversity and how integrating these perspectives can help ensure the resilience of this nexus of human and natural history in the Anthropocene future.

The maritime fur trade caused the extirpation of sea otters from southeast Alaska. In the 1960s, sea otters were reintroduced, and their numbers have increased. Now, sea otters are competing with people for what have become commercially important invertebrates. After having been absent for more than a century, the reentry of this keystone species has unsettled people. Although some communities perceive sea otters as a threat to their livelihoods, others view their return as restoration of the marine ecosystem. The federal Marine Mammal Protection Act authorizes any Alaska Native to harvest sea otters for subsistence provided that the harvest is not wasteful. Some people are seeking to define “traditional” Tlingit use of sea otters as not only using their pelts but consuming them as food, but some Tlingit maintain they never ate sea otters. This project analyzes the largest precontact archaeological assemblage of sea otter bones in southeast Alaska, with the benefit of insights gained from observing a Tlingit hunter skin a sea otter to infer that Tlingit ancestors hunted sea otters primarily for pelts. The extent to which other Indigenous peoples of the North Pacific consumed sea otters as food deserves investigation, especially as sea otters recolonize their historic range.

Culturally modified trees (CMTs) provide tangible evidence of long-term forest use by Indigenous peoples. In Northwest Coast cedar forests, this record rarely spans beyond the last three centuries because older bark-harvest scars have been obscured through taphonomic processes such as natural healing and decay. Thus, archaeological visibility and identification are hindered. Here, I recover chronologies of ancient forest harvesting using a post-impact assessment methodology of targeting old-growth clear-cuts in southern Nuu-chah-nulth territories on the west coast of Vancouver Island, British Columbia, Canada. Bark-peeling scars are identified and dated in cross section by growth-ring patterns of recently logged trees. Approximately half of all bark-peeling scars are “embedded” inside healing lobes, suggesting at least half of all such CMTs are effectively invisible in standing forests. Features in these post-impact surveys predated those discovered in conventional archaeological impact assessments by a mean of almost a century. Additionally, one of the oldest continually used cultural forests ever recorded, dating to AD 908, is found in the Toquaht Nation traditional territory. These findings uncover measurable frequencies of cedar-bark harvesting generations prior to the contact period and reveal the inadequacy of heritage protections for old-growth cedar stands.

Declining sea ice is expected to change the Arctic's physical and biological systems in ways that are difficult to predict. This study used stable isotope compositions (δ13C and δ15N) of archaeological, historic, and modern Pacific walrus (Odobenus rosmarus divergens) bone collagen to investigate the impacts of changing sea ice conditions on walrus diet during the last ~4000 yr. An index of past sea ice conditions was generated using dinocyst-based reconstructions from three locations in the northeastern Chukchi Sea. Archaeological walrus samples were assigned to intervals of high and low sea ice, and δ13C and δ15N were compared across ice states. Mean δ13C and δ15N values were similar for archaeological walruses from intervals of high and low sea ice; however, variability among walruses was greater during low-ice intervals, possibly indicating decreased availability of preferred prey. Overall, sea ice conditions were not a primary driver of changes in walrus diet. The diet of modern walruses was not consistent with archaeological low sea ice intervals. Rather, the low average trophic position of modern walruses (primarily driven by males), with little variability among individuals, suggests that trophic changes to this Arctic ecosystem are still underway or are unprecedented in the last ~4000 yr.

Coastal ecosystems have been degraded by human activity over centuries, with loss of memory about past states resulting in shifted baselines. More recently conservation efforts have resulted in localized recoveries of species and ecosystems. Given the dynamism of ecosystem degradation and recovery, understanding how communities perceive long-term and recent changes is important for developing and implementing conservation measures. We interviewed stakeholders on three Caribbean islands and identified a shifted baseline with respect to the extent and degree of long-term declines in marine animal populations; stakeholders with more experience identified more species as depleted and key species as less abundant than those with less experience. Notably, the average respondent with < 15 years of experience listed no species as depleted despite clear evidence of declines. We also identified a phenomenon we call the policy placebo effect, in which interviewees perceived some animal populations as recently recovering following passage of new conservation legislation but in the absence of evidence for actual recovery. Although shifted baselines have a negative effect on conservation as they can lower recovery goals, the outcomes of a policy placebo effect are unclear. If the public prematurely perceives recovery, motivation for continued conservation could decline. Alternatively, perception of rapid success could lead communities to set more ambitious conservation goals.

Isolation can provide marine ecosystems with a refuge from human impacts. However, information on the biodiversity, ecology and fisheries of remote regions is often sparse. The proposed Coral Sea Marine Reserve could create one of the world's largest and most remote marine parks, yet little information is available to inform discussions. Fish captures from the Coral Sea and adjacent Great Barrier Reef (GBR) were assessed from reports contained in a chronology of spearfishing publications from 1953 to 2009, and reveal for the first time the history of recreational spearfishing in the Coral Sea. Although the area is perceived as relatively untouched, the data indicate that spearfishers have frequented Coral Sea reefs for at least 43 years and reported captures have increased exponentially. Post-1993 trophy captures in the Coral Sea (mean 23 kg) were larger than the adjacent GBR (9 kg). Reef species characterize the GBR catch, while large pelagic species characterize the Coral Sea catch. Provided that functionally important fishes are not targeted, the relatively small scale of recreational spearfishing and the focus on pelagic species suggests that spearfishing currently exerts limited pressure on the ecology of Coral Sea reefs.

Papua New Guinea (PNG) has been the site of a great deal of scientific work, and a fair amount of interdisciplinary debate, within the broad field of historical ecology, which encompasses the study of indigenous society-environment relationships over different time periods. However, this in itself provides no guarantee that scientists engaged in such debate will have a greater influence on the formulation of environmental conservation policies in a state where indigenous decision makers now hold the levers of political power. Five environmental policy paradigms which have emerged in the course of public debate about environmental conservation in PNG over the past half century; the wildlife management, environmental planning, biodiversity conservation, ecosystem assessment, and carbon sequestration paradigms. Each paradigm has framed a distinctive form of interdisciplinary debate about indigenous society-environment relationships within a contemporary political framework. However, a further connection can be drawn between the role of interdisciplinary debate in an evolving national policy framework and the history of scientific debate about the nature of indigenous society-environment relationships in the pre-colonial era. This connection places a distinctive emphasis on the relationship between indigenous agricultural practices and management of the national forest estate for reasons which are themselves a contingent effect of the nature of European colonial intervention over the course of the last century and a half. This particular bias in the relationship between historical ecology and environmental policy has lasted down to the present day. PNG's environmental policy problems are unlikely to have any rational or sensible solution in the absence of a better scientific understanding of the complexity of indigenous society-environment relationships. Scientists need to understand the complexity of the environmental policy process as a historical process in its own right in order to work out which policy problems offer both the scope and the incentive to sustain specific forms of interdisciplinary debate that are likely to produce better policy outcomes.

In recent decades, the interconnectedness of history and ecology has received increasing attention. Although necessarily interdisciplinary, efforts to study this interconnectedness had their roots either in the humanities and social sciences or in the natural sciences: scholars have tried either to understand more about nature with the help of history, or, about human history with the help of natural phenomena. As a result, theoretical studies about the integration of ecology and history try to answer two relatively distinct questions: ‘why ecology matters in history’ and ‘why history matters in ecology’. This paper sets out to systematize current knowledge on the latter question and to highlight those issues that have so far received less attention. The arguments can be grouped into three major themes. First, history matters in ecology because it aids understanding of current patterns and processes in nature. Second, because it fosters better informed management and policy decisions; and third, because it places ecology and conservation in a wider interdisciplinary context. Besides dealing with the perspectives of ecologists and conservationists, this paper also includes material from historians, anthropologists and archaeologists, that is, from scholars whose primary interest does not lie in ecological investigations, but who have, nonetheless, embraced the need for the integration of ecology and history.