Marbled Teal Marmaronetta angustirostris is a globally threatened species that has been undergoing population declines across much of its range in recent years. This is particularly true in the Middle East and the Caucasus, where the species once commonly bred across much of the region. However, there is a dearth of recent literature and population-level assessments of the species in the countries in this region. For example, the last update of conservation status for Marbled Teal in Armenia was undertaken in 2009 and in Türkiye in 2008. Therefore, this study addresses the urgent need for an updated evaluation of the species’ status in both Armenia and Türkiye. For Armenia, the current population estimate is 8–11 breeding pairs, with a steep decline of 87% between 2003 and 2019. In Türkiye, the species appears to be functionally extirpated from the country due to an absence of breeding in almost a decade and multiple years without any records, with only a handful of wandering individuals detected in recent years. This study highlights the threats facing the species, particularly changes to wetland habitat and quality as well as hunting pressures and illegal poaching. Based on our findings, we propose that the conservation status of Marbled Teal in both countries be updated from “Endangered” to “Critically Endangered”. Finally, we note the conservation requirements for the species in the region and provide a set of recommendations for its protection, including a species recovery plan. Without urgent conservation measures such as the creation of new protected areas and establishment of new populations from released birds, the long-term viability of Marbled Teal populations in the region is in jeopardy.

The southern African shrub boneseed [Chrysanthemoides monilifera subsp. monilifera (L.) Norl.] is a perennial shrub that is a significant threat to natural ecosystems and is listed as a Weed of National Significance in Australia. In Western Australia (WA) it has spread across peri-urban and natural environments. We assembled a single standardized database containing more than 2,050 presence records for individual plants and 135 absence records at a local population level. We further refined the populations into 89 sites that require different management trajectories due to topography and capacity of land managers to implement control. Forty-nine of these sites were in urban regions and 40 sites were in regional WA. We split these 89 sites into three near-term management goals: watch (12), extirpate (68), and contain (9). The 12 watch sites are those where all available evidence suggests that there have been no new inputs into the seedbank for 15 yr. The 68 sites marked for extirpation are those where delimitation is already achieved or easily achievable, where there have been minimal seed inputs into the soil seedbank in recent years due to consistent surveillance and control, and where surveys for new plants are likely to be efficient to conduct. Finally, for nine sites in urban regions around Perth, we recommend containment in the near term with a longer-term goal to achieve delimitation and extirpation. To achieve the objective of state-level eradication, a coordinated and sustained campaign involving three components—delimitation of all sites, prevention of further inputs into the soil seedbank, and systematic field surveys to remove plants—must commence without delay. While resourcing requirements for delimitation and overall program management are not possible to estimate, our prior experience suggests that it will take at least 1,900 h of on-ground surveying by experienced personnel to achieve extirpation of C. monilifera subsp. monilifera in WA.

1. 1. Understanding whether a species still persists, or the timing of its extinction is challenging, however, such knowledge is fundamental for effective species management.

2. 2. For the vast majority of species our understanding of their existence is based solely on sighting data that can range from museum specimens and clear photographs, through vocalisations, to markings and oral accounts.

3. 3. Here we review the methods that have been developed to infer the extinction of species from a sighting record, providing an understanding of their assumptions and applications. We have also produced an RShiny package which can be used to implement some of the methods presented in the article.

4. 4. While there are a number of potential areas that could be further developed, the methods reviewed provide a useful tool for inferring species extinction.

In 2021, scientists published a preprint stating that the dugong population of Okinawa had declined below the minimum viable population and should be considered extinct. The publication led to an outcry amongst Japanese/Okinawan environmentalists and to criticism by international dugong specialists. Two issues were raised: 1) Declaring dugongs extinct, although feeding trails were found in several locations, misrepresented the reality in Okinawan waters, and could have negative impacts on conservation measures; 2) Three authors were sitting on the Environmental Monitoring Committee for a controversial military base construction project in an area where dugongs were frequently spotted before construction commenced. The presence/absence of dugongs at the site had become a political issue, as the animal’s protected status and its depiction in folklore gave it symbolic meaning in the anti-base movement. The declaration of dugong extinction reminded protesters of a former Environmental Impact Assessment conducted by Japan’s Ministry of Defence, declaring the site to be no relevant dugong habitat. The paper explores the implications of the preprint for the political situation in Okinawa and questions the certainty of dugong extirpation in the region. It argues that speculations about extinction cannot be divorced from the political contexts to which they are invariably tied.

Between 20 and 24 marine extinctions, ranging from algal to mammal species, have occurred over the past 500 years. These relatively low numbers question whether the sixth mass extinction that is underway on land is also occurring in the ocean. There is, however, increasing evidence of worldwide losses of marine populations that may foretell a wave of oncoming marine extinctions. A review of current methods being used to determine the loss of biodiversity from the world’s oceans reveals the need to develop and apply new assessment methodologies that incorporate standardized metrics that allow comparisons to be made among different regions and taxonomic groups, and between current extinctions and past mass extinction events. Such efforts will contribute to a better understanding of extinction risk facing marine flora and fauna, as well as the ways in which it can be mitigated.

The eradication of an invasive plant species can provide substantial ecological and economic benefits by eliminating completely the negative effects of the weed and reducing the high cost of continuing control. A 5-yr program toward the eradication of hill raspberry (Rubus niveus Thunb.) in Santiago Island is evaluated using delimitation and extirpation criteria, as well as assessment of the ecological community response to management techniques. Currently, hill raspberry is located in the humid zone of Santiago island. It is distributed over three main infestations, small patches, and many scattered individuals within an area of approximately 1,000 ha. New infestations are constantly being found; every year, new detections add an area of approximately 175 ha. Adult and juvenile individuals are still found, both beyond and within known infestations. Both plant and seed bank density of hill raspberry decreased over time where infestations were controlled. Species composition in the seed bank and existing vegetation were significantly different between areas under intensive control and adjacent uninvaded forest. After 5 yr of intensive management, delimitation of hill raspberry has not been achieved; new populations are found every year, increasing the infested area that requires management. Off-target effects on native species resulting from control efforts seem to be substantial. Although a vast increase in economic investment would allow intensive searching that might enable all individuals to be found and controlled, the resultant disturbance and off-targets effects could outweigh the conservation benefits of eradication.

Because weed eradication programs commonly take 10 or more years to complete, there is a need to evaluate progress toward the eradication objective. We present a simple model, based on information that is readily obtainable, that assesses conformity to the delimitation and extirpation criteria for eradication. It is applied to the program currently targeting the annual parasitic weed, branched broomrape, in South Australia. The model consists of delimitation and extirpation (E) measures plotted against each other to form an ‘eradograph.’ Deviations from the ‘ideal’ eradograph plot can inform tactical responses, e.g., increases in survey and/or control effort. Infestations progress from the active phase to the monitoring phase when no plants have been detected for at least 12 mo. They revert to the active phase upon further detection of plants. We summarize this process for the invasion as a whole in a state-and-transition model. Using this model we demonstrate that the invasion is unlikely to be delimited unless the amount of newly detected infested area decreases, on average, by at least 50% per annum. As a result of control activities implemented, on average approximately 70% (range, 44 to 86%) of active infestations progressed to the monitoring phase in the year following their detection. Simulations suggest that increasing this rate of transition will not increase E to a significant extent. The rate of reversion of infestations from the monitoring phase to the active phase decreased logarithmically with time since last detection, but it is likely that lower rates of reversion would accelerate the trend toward extirpation. Program performance with respect to the delimitation criterion has been variable; performance with respect to the extirpation criterion would be improved considerably by the development and application of cost-effective methods for eliminating branched broomrape soil seed populations.

There has been recent interest in determining the upper limits to the feasibility of weed eradication. Although a number of disparate factors determine the success of an eradication program, ultimately eradication feasibility must be viewed in the context of the amount of investment that can be made. The latter should reflect the hazard posed by an invasion, with greater investment justified by greater threats. In simplest terms, the effort (and hence investment) to achieve weed eradication comprises the detection effort required to delimit an invasion plus the search and control effort required to prevent reproduction until extirpation occurs over the entire infested area. The difficulty of estimating the required investment at the commencement of a weed eradication program (as well as during periodic reviews) is a serious problem. Bioeconomics show promise in determining the optimal approach to managing weed invasions, notwithstanding ongoing difficulties in estimating the costs and benefits of eradication and alternative invasion management strategies. A flexible approach to the management of weed invasions is needed, allowing for the adoption of another strategy when it becomes clear that the probability of eradication is low, owing to resourcing or intractable technical issues. Whether the considerable progress that has been achieved towards eradication of the once massive witchweed invasion can be duplicated for other weeds of agricultural systems will depend to a large extent upon investment (> $250 million over 50 yr in this instance). Weeds of natural ecosystems seem destined to remain more difficult eradication targets for a variety of reasons, including higher impedance to eradication, more difficulty in valuing the benefits arising from eradication, and possibly less willingness to pay from society at large.

To eradicate a weed invasion, its extent must be delimited and each infestation must be extirpated. Measures for both of these criteria are utilized to assess the progress of current eradication programs targeting mikania vine and limnocharis in northern Australia. The known infested area for each species is less than 5 ha and has remained largely static for the last 3 or more years against a backdrop of refined and enhanced detection methods. This suggests that delimitation has been approached, if not achieved. Different methods of detection have their places, relative to the stage of the program and the spatial distribution of infestations. Although all known infestations of both species are effectively monitored and controlled, ongoing emergence from persistent seed banks limits progress towards the extirpation of infestations to a slow, but measurable, rate.

Extirpation or even extinction of freshwater invertebrate species is a neglected conservation issue; declines in abundance and spatial distribution for freshwater invertebrates are far less documented than for vertebrate species. In the Minho River tidal freshwater wetlands (northwest of Iberian Peninsula), a rapid decline in density and biomass of the bivalve Pisidium amnicum was recorded at 16 different sites over seven years, from 2004 to 2010, without any sign of a potential recovery. Mean density values reached more than 80 ind.m−2 in 2004, but declined to less than 1 ind.m−2 in 2009 and 2010. An identical declining trend was observed for biomass. A significant reduction in the spatial distribution also occurred. The abiotic changes resulting from the 2005 heat wave and possibly the negative interactions imposed by the non-indigenous invasive bivalve Corbicula fluminea were the main factors responsible for the declining trends. Given the very low density, P. amnicum is facing a serious risk of extirpation in this ecosystem and conservational measures are urgently needed.

Large protected areas are often considered natural yet outside pressures may compromise ecological integrity. This paper points to a problem in assessing ecological baselines: what if species’ extirpations go undetected? I present a data set spanning 130 years that demonstrates the loss of white-tailed jack rabbits Lepus townsendii from two National Parks in the well studied 60,000 km2 Greater Yellowstone Ecosystem, USA. While these extirpations have been unnoticed until now, an ecological consequence may be elevated predation on juvenile ungulates. A critical challenge we face is how to apply better the concept of shifting baselines to the restoration of functional relationships when species' losses are undetected.

A review was carried out of the mammalian fauna of the Kilum-Ijim forest in the mountains of northwest Cameroon. The purpose was to examine the loss of species, particularly of larger mammals, and the implications of this for forest ecology. Information was collected by direct observation, hunter interviews and a literature review. The forest is the largest remaining representative fragment of the West African montane forest habitat. Seventy-seven species of mammal have been recorded in the forest over the last 50 years. Most are small, especially rodents, bats and insectivores. Seven species are endemic to the Kilum-Ijim area. The process of species extirpation probably began over 100 years ago with the loss of the mega-fauna, possibly beginning with elephant Loxodonta africana (several generations ago), and certainly with buffalo Syncerus caffer (at least 20 years ago), and other large mammals. Remaining large mammal population densities are very low and many species are close to regional extinction. The long-term consequences of these extinctions is uncertain but, as many tree species are monkey- or ruminant-dispersed, severe ecosystem damage has probably already occurred. Human population density in the area is around 300 people per sq km, and no sustainable offtake of wild animals will ever be possible that would provide more than a few grams of meat per person per year from the forest. The protein requirements of the communities of the area will have to continue to be supplied from domesticated stock. Since 1987 the Kilum-Ijim Forest Project of BirdLife International has been working to conserve the remaining forest, using a community forestry approach in collaboration with traditional and local authorities and the government of Cameroon. The project is investigating ways to improve the production of domestic animals outside the forest boundary.

The present study deals with the interrelationship of the neuroendocrine complex (NEC) and male accessory reproductive gland (ARG) of a cotton bug, Serinetha augur. The NEC consists of brain (cerebral ganglia), corpus cardiacam (CC) and corpus allatum (CA). Based on the staining reaction of aldehyde fuchsin (AF) and chrom alum haematoxylin-phloxin (CAHP), four types of neurosecretory cells have been identified in the brain. The neuroendocrine control over the ARG in S. augury was investigated through ARG extirpation (andgonadectomy)-induced hypertrophy of CA. The changing pattern of proteins in the brain during the pre- and post-mating periods (as judged by electrophoretic investigations) further supports the interrelationship of the NEC and ARG.