Historical data as a baseline for conservation: reconstructing long-term faunal extinction dynamics in Late Imperial–modern China

Extinction events typically represent extended processes of decline that cannot be reconstructed using short-term studies. Long-term archives are necessary to determine past baselines and the extent of human-caused biodiversity change, but the capacity of historical datasets to provide predictive power for conservation must be assessed within a robust analytical framework. Local Chinese gazetteers represent a >400-year country-level dataset containing abundant information on past environmental conditions and include extensive records of gibbons, which have a restricted present-day distribution but formerly occurred across much of China. Gibbons show pre-twentieth century range contraction, with significant fragmentation by the mid-eighteenth century and population loss escalating in the late nineteenth century. Isolated gibbon populations persisted for ~40 years before local extinction. Populations persisted for longer at higher elevations, and disappeared earlier from northern and eastern regions, with the biogeography of population loss consistent with the contagion model of range collapse in response to human demographic expansion spreading directionally across China. The long-term Chinese historical record can track extinction events and human interactions with the environment across much longer timescales than are usually addressed in ecology, contributing novel baselines for conservation and an increased understanding of extinction dynamics and species vulnerability or resilience to human pressures

Understanding local knowledge and attitudes toward potential reintroduction of a former British wetland bird

Stakeholder acceptance and support is essential for long-term success in species reintroductions, and assessing social feasibility of reintroductions within human-occupied landscapes is an integral component of effective decision-making. The Dalmatian pelican Pelecanus crispus is an extirpated British bird, and possible pelican reintroduction to British wetlands is under discussion. Any reintroduction planning must first assess local community awareness, attitudes, and acceptance of potential pelican arrival and associated habitat management, as part of wider socio-ecological feasibility assessment. Pelicans are distinctive species with potential to increase support for wetland conservation, but might provoke conflict through real or perceived competition with landscape users such as fishers; such conflict is already seen within Britain between fishers and cormorants. We conducted an online survey of 590 respondents in the Somerset Levels and East Anglian Fens, Britain's largest wetland landscapes, to understand local views on pelican reintroduction, other reintroductions and wetland restoration, and to investigate correlates of varying attitudes toward coexistence with pelicans and five other waterbirds (grey heron, Eurasian bittern, little egret, common crane, great cormorant). Respondents had generally positive views about previous reintroductions of other species, and had overall positive attitudes toward all six waterbirds. Two-thirds of respondents supported or strongly supported pelican reintroduction, but both benefits and concerns were identified in relation to its possible reintroduction. Anglers and hunters were more likely to hold negative attitudes toward pelicans, other waterbirds and wetland restoration. However, although anglers raised more concerns, they were not more likely to be unsupportive toward reintroduction. More socio-demographic predictors were associated with negative attitudes toward restoration required to establish pelican habitat, suggesting that positive feelings toward biodiversity are outweighed by concerns around potential exclusion from local landscapes. Our findings suggest pelican reintroduction might be supported by local stakeholders. Attitudes toward cormorants do not represent a blueprint for attitudes toward pelicans, and anglers may support reintroduction if concerns around impacts to fish stocks are addressed. Community engagement for species-specific and landscape-scale actions require separate approaches, with landscape management planning needing to target a wider range of stakeholder groups with separate concerns to those about coexistence with pelicans

Complementarity, completeness and quality of long-term faunal archives in an Asian biodiversity hotspot

Long-term baselines on biodiversity change through time are crucial to inform conservation decision-making in biodiversity hotspots, but environmental archives remain unavailable for many regions. Extensive palaeontological, zooarchaeological and historical records and indigenous knowledge about past environmental conditions exist for China, a megadiverse country experiencing large-scale biodiversity loss, but their potential to understand past human-caused faunal turnover is not fully assessed. We investigate a series of complementary environmental archives to evaluate the understand past human-caused faunal turnover is not fully assessed. We investigate a series of complementary environmental archives to evaluate the quality of the Holocene-historical faunal record of Hainan Island, China’s southernmost province, for establishing new baselines on postglacial mammalian diversity and extinction dynamics. Synthesis of multiple archives provides an integrated model of long-term biodiversity change, revealing that Hainan has experienced protracted and ongoing human-caused depletion of its mammal fauna from prehistory to the present, and that past baselines can inform practical conservation management. However, China’s Holocene-historical archives exhibit substantial incompleteness and bias at regional and country wide scales, with limited taxonomic representation especially for small-bodied species, and poor sampling of high-elevation landscapes facing current-day climate change risks. Establishing a clearer understanding of the quality of environmental archives in threatened ecoregions, and their ability to provide a meaningful understanding of the past, is needed to identify future conservation relevant historical research priorities

Quaternary vertebrate faunas from Sumba, Indonesia: implications for Wallacean biogeography and evolution

Historical patterns of diversity, biogeography and faunal turnover remain poorly understood for Wallacea, the biologically and geologically complex island region between the Asian and Australian continental shelves. A distinctive Quaternary vertebrate fauna containing the small-bodied hominin Homo floresiensis, pygmy Stegodon proboscideans, varanids and giant murids has been described from Flores, but Quaternary faunas are poorly known from most other Lesser Sunda Islands. We report the discovery of extensive new fossil vertebrate collections from Pleistocene and Holocene deposits on Sumba, a large Wallacean island situated less than 50 km south of Flores. A fossil assemblage recovered from a Pleistocene deposit at Lewapaku in the interior highlands of Sumba, which may be close to 1 million years old, contains a series of skeletal elements of a very small Stegodon referable to S. sumbaensis, a tooth attributable to Varanus komodoensis, and fragmentary remains of unidentified giant murids. Holocene cave deposits at Mahaniwa dated to approximately 2000–3500 BP yielded extensive material of two new genera of endemic large-bodied murids, as well as fossils of an extinct frugivorous varanid. This new baseline for reconstructing Wallacean faunal histories reveals that Sumba's Quaternary vertebrate fauna, although phylogenetically distinctive, was comparable in diversity and composition to the Quaternary fauna of Flores, suggesting that similar assemblages may have characterized Quaternary terrestrial ecosystems on many or all of the larger Lesser Sunda Islands

Mammalian tolerance to humans is predicted by body mass: evidence from long-term archives.

Humans are implicated as a major driver of species extinctions from the Late Pleistocene to the present. However, our predictive understanding of human-caused extinction remains poor due to the restricted temporal and spatial scales at which this process is typically assessed, and the risks of bias due to "extinction filters" resulting from a poor understanding of past species declines. We develop a novel continent-wide dataset containing country-level last-occurrence records for 30 European terrestrial mammals across the Holocene (c.11,500 years to present), an epoch of relative climatic stability that captures major transitions in human demography. We analyze regional extirpations against a high-resolution database of human population density (HPD) estimates to identify species-specific tolerances to changing HPD through the Holocene. Mammalian thresholds to HPD scale strongly with body mass, with larger-bodied mammals experiencing regional population losses at lower HPDs than smaller-bodied mammals. Our analysis enables us to identify levels of tolerance to HPD for different species, and therefore has wide applicability for determining biotic vulnerability to human impacts. This ecological pattern is confirmed across wide spatiotemporal scales, providing insights into the dynamics of prehistoric extinctions and the modern biodiversity crisis, and emphasizing the role of long-term archives in understanding human-caused biodiversity loss. This article is protected by copyright. All rights reserved.© 2019 Ecological Society of America. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/ecy.278

Late Quaternary megafaunal extinctions in India: how much do we know?

Understanding global patterns of late Quaternary megafaunal extinction is impeded by geographic variation in data quality and quantity. The magnitude, timing and drivers of megafaunal extinctions remain poorly understood for India, a region with a strong history of palaeontological research. We review available data for all putative extinct Indian megafaunal taxa with direct or indirect reported evidence of potential survival into the global “megafaunal extinction window” (from ∼50,000 years onwards). Assessment of late Quaternary megafaunal species richness is confused by multiple levels of taxonomic uncertainty, including the relationship of named Late Pleistocene taxa to extant taxa, and nomenclatural confusion over correct species names. There is sufficient evidence to recognise up to four genuine global megafaunal species-level extinctions in India during the Late Pleistocene: two proboscideans (Palaeoloxodon namadicus, Stegodon sp.), a hippopotamus (Hexaprotodon sp.), and possibly a horse (Equus namadicus). A fifth extinct megafaunal species, the Indian aurochs Bos [primigenius] namadicus, definitely persisted into the Holocene. Other Indian late Quaternary megafaunal species (Rhinoceros spp., Bubalus palaeindicus, Sus “palaeindicus”, Crocodylus palaeindicus) are likely to be synonyms of extant species. Reconstructing regional extinction dynamics is further impeded by chronological uncertainty; however, attempts to obtain new dates for vertebrate samples from six late Quaternary sites in five regions were unsuccessful. Accurate understanding of the dynamics of megafaunal extinctions in India will require robust taxonomic, chronological and palaeoecological data, and we encourage further investigation of the region’s rich late Quaternary record

Bias, incompleteness and the ‘known unknowns’ in the Holocene faunal record

Long-term faunal data are needed to track biodiversity change and extinction over wide spatio-temporal scales. The Holocene record is a particularly rich and well-resolved resource for this purpose but nonetheless represents a biased subset of the original faunal composition, both at the site-level assemblage and when data are pooled for wider-scale analysis. We investigated patterns and potential sources of taxonomic, spatial and temporal bias in two Holocene datasets of mammalian occurrence and abundance, one at the global species level and one at the continental population-level. Larger-bodied species are disproportionately abundant in the Holocene fossil record, but this varies according to trophic level, probably owing to past patterns of human subsistence and exploitation. Despite the uneven spatial distribution of mammalian occurrence records, we found no specific source of sampling bias, suggesting that this error type can be avoided by intensive data collection protocols. Faunal assemblages are more abundant and precisely dated nearer to the present as a consequence of taphonomy, past human demography and dating methods. Our study represents one of the first attempts to quantify incompleteness and bias in the Holocene mammal record, and failing to critically assess the quality of long-term faunal datasets has major implications for understanding species decline and extinction risk. This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?