Publications by authors named "Damien A Fordham"

(caribou or reindeer) survived periods of abrupt climatic warming during the last deglaciation but are currently in global decline. Using process-explicit models of likely climate-human- interactions and inferences of demographic change from radiocarbon-dated fossils and ancient DNA, we reconstruct and decipher 21,000 years of population dynamics. These high-resolution population reconstructions pinpoint ecological characteristics and life-history traits that most likely enabled to survive rapid warming events following the Last Glacial Maximum.

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Bowhead whales () are strongly associated with Arctic sea ice during their crucial summer feeding period. However, anthropogenic climate change is causing a decline in sea ice concentrations, threatening bowhead whale suitable habitat. To characterise the long-term affinity of bowhead whales to sea ice across the Holocene and project the response of populations to 21st century climate change, we built ecological models of occurrence-environmental relationships using distribution-wide fossil, historical, and contemporary records.

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Accurately predicting the vulnerabilities of species to climate change requires a more detailed understanding of the functional and life-history traits that make some species more susceptible to declines and extinctions in shifting climates. This is because existing trait-based correlates of extinction risk from climate and environmental disturbances vary widely, often being idiosyncratic and context dependent. A powerful solution is to analyse the growing volume of biological data on changes in species ranges and abundances using process-explicit ecological models that run at fine temporal and spatial scales and across large geographical extents.

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Human overexploitation contributed strongly to the loss of hundreds of bird species across Oceania, including nine giant, flightless birds called moa. The inevitability of anthropogenic moa extinctions in New Zealand has been fiercely debated. However, we can now rigorously evaluate their extinction drivers using spatially explicit demographic models capturing species-specific interactions between moa, natural climates and landscapes, and human colonists.

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Article Synopsis
  • Human settlement in the Pacific led to rapid faunal extinctions, including the large, flightless moa birds endemic to New Zealand.
  • Researchers reconstructed the extinction dynamics of six moa species using extensive simulations of climate and human interactions, validated with fossil records.
  • The study found that while different species had unique extinction traits, their geographic range declines were similar, with last populations surviving in isolated, suboptimal habitats, which offers insights for conserving New Zealand's remaining flightless birds.
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Spatial and temporal patterns of future coral bleaching are uncertain, hampering global conservation efforts to protect coral reefs against climate change. Our analysis of daily projections of ocean warming establishes the severity, annual duration, and onset of severe bleaching risk for global coral reefs this century, pinpointing vital climatic refugia. We show that low-latitude coral regions are most vulnerable to thermal stress and will experience little reprieve from climate mitigation.

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  • The extinction of the woolly rhinoceros during the Holocene is complex and involves both climate change and human hunting pressure affecting its population dynamics over thousands of years.
  • Researchers used fossil records, ancient DNA, and simulation models to investigate these dynamics and discovered that the decline began before the Holocene, largely due to cooler temperatures and human hunting, which restricted the rhinos to less suitable habitats.
  • The study emphasizes the importance of understanding metapopulation dynamics, suggesting that habitat fragmentation and the ecological challenges faced by large grazers today highlight a concerning trend linked to environmental changes caused by human activities.
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Ocean warming and species exploitation have already caused large-scale reorganization of biological communities across the world. Accurate projections of future biodiversity change require a comprehensive understanding of how entire communities respond to global change. We combined a time-dynamic integrated food web modeling approach (Ecosim) with previous data from community-level mesocosm experiments to determine the independent and combined effects of ocean warming, ocean acidification and fisheries exploitation on a well-managed temperate coastal ecosystem.

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Drivers and dynamics of initial human migrations across individual islands and archipelagos are poorly understood, hampering assessments of subsequent modification of island biodiversity. We developed and tested a new statistical-simulation approach for reconstructing the pattern and pace of human migration across islands at high spatiotemporal resolutions. Using Polynesian colonisation of New Zealand as an example, we show that process-explicit models, informed by archaeological records and spatiotemporal reconstructions of past climates and environments, can provide new and important insights into the patterns and mechanisms of arrival and establishment of people on islands.

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  • European bison were once common in Europe but faced near extinction due to a mix of environmental changes and human activities, especially during the late Pleistocene and into the Holocene.
  • The population sharply declined as the Pleistocene ended, primarily due to rapid environmental shifts and increased hunting pressure from humans, which inhibited recovery even when conditions improved.
  • Key findings indicate that while human hunting significantly contributed to their decline, extensive habitat loss occurred from post-glacial changes, implying that these areas should not be targeted for attempts to reintroduce the species.
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The Arctic is among the most climatically sensitive environments on Earth, and the disappearance of multiyear sea ice in the Arctic Ocean is predicted within decades. As apex predators, polar bears are sentinel species for addressing the impact of environmental variability on Arctic marine ecosystems. By integrating genomics, isotopic analysis, morphometrics, and ecological modeling, we investigate how Holocene environmental changes affected polar bears around Greenland.

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  • Coral reef fisheries face sustainability threats from social and ecological challenges, mainly driven by climate change, which impacts their role in food and nutrition security.
  • Warming oceans may change fish nutrient levels through both direct effects (like metabolism) and indirect effects (such as shifts in habitats and species distributions).
  • Future research should focus on evaluating not just the quantity of fish available but also their nutritional quality, using biological traits to predict how climate impacts nutrient availability in coral reef food webs.
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Processes leading to range contractions and population declines of Arctic megafauna during the late Pleistocene and early Holocene are uncertain, with intense debate on the roles of human hunting, climatic change, and their synergy. Obstacles to a resolution have included an overreliance on correlative rather than process-explicit approaches for inferring drivers of distributional and demographic change. Here, we disentangle the ecological mechanisms and threats that were integral in the decline and extinction of the muskox (Ovibos moschatus) in Eurasia and in its expansion in North America using process-explicit macroecological models.

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Article Synopsis
  • Advances in data availability and computational power allow for the broader use of process-explicit models to study biodiversity patterns over time and space.
  • Traditional experimental methods are limited due to large-scale ecological factors, so researchers can now simulate mechanisms in virtual environments and compare patterns with real data.
  • Recent developments in these models enhance our understanding of how organisms, communities, and ecosystems are distributed and change, ultimately improving biodiversity management and scientific knowledge.
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The vulnerability of marine biodiversity to accelerated rates of climatic change is poorly understood. By developing a new method for identifying extreme oceanic warming events during Earth's most recent deglaciation, and comparing these to 21st century projections, we show that future rates of ocean warming will disproportionately affect the most speciose marine communities, potentially threatening biodiversity in more than 70% of current-day global hotspots of marine species richness. The persistence of these richest areas of marine biodiversity will require many species to move well beyond the biogeographic realm where they are endemic, at rates of redistribution not previously seen.

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Pathways to extinction start long before the death of the last individual. However, causes of early stage population declines and the susceptibility of small residual populations to extirpation are typically studied in isolation. Using validated process-explicit models, we disentangle the ecological mechanisms and threats that were integral in the initial decline and later extinction of the woolly mammoth.

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One of the biggest challenges in more accurately forecasting the effects of climate change on future food web dynamics relates to how climate change affects multi-trophic species interactions, particularly when multiple interacting stressors are considered. Using a dynamic food web model, we investigate the individual and combined effect of ocean warming and acidification on changes in trophic interaction strengths (both direct and indirect) and the consequent effects on biomass structure of food web functional groups. To do this, we mimicked a species-rich multi-trophic-level temperate shallow-water rocky reef food web and integrated empirical data from mesocosm experiments on altered species interactions under warming and acidification, into food-web models.

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The Komodo dragon () is an endangered, island-endemic species with a naturally restricted distribution. Despite this, no previous studies have attempted to predict the effects of climate change on this iconic species. We used extensive Komodo dragon monitoring data, climate, and sea-level change projections to build spatially explicit demographic models for the Komodo dragon.

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Paleoclimatic data are used in eco-evolutionary models to improve knowledge of biogeographical processes that drive patterns of biodiversity through time, opening windows into past climate-biodiversity dynamics. Applying these models to harmonised simulations of past and future climatic change can strengthen forecasts of biodiversity change. StableClim provides continuous estimates of climate stability from 21,000 years ago to 2100 C.

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Strategies for 21st-century environmental management and conservation under global change require a strong understanding of the biological mechanisms that mediate responses to climate- and human-driven change to successfully mitigate range contractions, extinctions, and the degradation of ecosystem services. Biodiversity responses to past rapid warming events can be followed in situ and over extended periods, using cross-disciplinary approaches that provide cost-effective and scalable information for species' conservation and the maintenance of resilient ecosystems in many bioregions. Beyond the intrinsic knowledge gain such integrative research will increasingly provide the context, tools, and relevant case studies to assist in mitigating climate-driven biodiversity losses in the 21st century and beyond.

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Knowledge of global patterns of biodiversity, ranging from intraspecific genetic diversity (GD) to taxonomic and phylogenetic diversity, is essential for identifying and conserving the processes that shape the distribution of life. Yet, global patterns of GD and its drivers remain elusive. Here we assess existing biodiversity theories to explain and predict the global distribution of GD in terrestrial mammal assemblages.

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The European rabbit (Oryctolagus cuniculus) is a notorious economic and environmental pest species in its invasive range. To better understand the population and range dynamics of this species, 41 yr of abundance data have been collected from 116 unique sites across a broad range of climatic and environmental conditions in Australia. We analyzed this time series of abundance data to determine whether interannual variation in climatic conditions can be used to map historic, contemporary, and potential future fluctuations in rabbit abundance from regional to continental scales.

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In its invasive range in Australia, the European rabbit threatens the persistence of native flora and fauna and damages agricultural production. Understanding its distribution and ecological niche is critical for developing management plans to reduce populations and avoid further biodiversity and economic losses.We developed an ensemble of species distribution models (SDMs) to determine the geographic range limits and habitat suitability of the rabbit in Australia.

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The stability of regional climates on millennial timescales is theorised to be a primary determinant of nearby diversification [1-5]. Using simulated patterns of past temperature change at monthly timescales [6], we show that the locations of climatically stable regions are likely to have varied considerably across and within millennia during glacial-interglacial cycles of the Late Quaternary. This result has important implications for the role of regional climate stability in theories of speciation, because long-term climate refugia are typically presumed to be 'cradles' of diversity (areas of high speciation) only if they remain stable across Milankovitch climate oscillations [1-5], which operate on multi-millennial time scales [7].

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With ongoing introductions into Australia since the 1700s, the European rabbit (Oryctolagus cuniculus) has become one of the most widely distributed and abundant vertebrate pests, adversely impacting Australia's biodiversity and agroeconomy. To understand the population and range dynamics of the species and its impacts better, occurrence and abundance data have been collected by researchers and citizens from sites covering a broad spectrum of climatic and environmental conditions in Australia. The lack of a common and accessible repository for these data has, however, limited their use in determining important spatiotemporal drivers of the structure and dynamics of the geographical range of rabbits in Australia.

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