Climate-driven Environmental Change Research Articles

Palaeoceanographic changes in Hornsund Fjord (Spitsbergen, Svalbard) over the last millennium: new insights from ancient DNA

Abstract. This paper presents a reconstruction of climate-driven environmental changes over the last millennium in Hornsund Fjord (Svalbard), based on sedimentological and micropalaeontological records. Our palaeo-investigation was supported by an analysis of foraminiferal ancient DNA (aDNA), focusing on the non-fossilized monothalamous species. The main climatic fluctuations during the last millennium were the Medieval Warm Period (MWP, AD 1000–1600), the Little Ice Age (LIA, AD 1600–1900) and the modern warming (MW, AD 1900 to present). Our study indicates that the environmental conditions in Hornsund during the MWP and the early LIA (before ∼ AD 1800) were relatively stable. The beginning of the LIA (∼ AD 1600) was poorly evidenced by the micropalaeontological record but was well marked in the aDNA data by an increased proportion of monothalamous foraminifera, especially Bathysiphon sp. The early LIA (∼ 1600 to ∼ AD 1800) was marked by an increase in the abundance of sequences of Hippocrepinella hirudinea and Cedhagenia saltatus. In the late LIA (after ∼ AD 1800), the conditions in the fjord became glacier-proximal and were characterized by increased meltwater outflows, high sedimentation and a high calving rate. This coincided with an increase in the percentages of sequences of Micrometula sp. and Vellaria pellucidus. During the MW, the major glacier fronts retreated rapidly to the inner bays, which limited the iceberg discharge to the fjord's centre and caused a shift in the foraminiferal community that was reflected in both the fossil and aDNA records. The palaeoceanographic changes in the Hornsund fjord over the last millennium were driven mainly by the inflow of shelf-originated water masses and glacial activity. However, the environmental changes were poorly evidenced in the micropalaeontological record, but they were well documented in our aDNA data. We considerably increased the number of potential proxy species by including monothalamous foraminifera in the palaeoecological studies.

The Influence of Community Size and Location on Different Dimensions of Vulnerability: a case study of Australian coastal communities

ABSTRACTCoastal communities are part of the Australian identity but little is known about their characteristics and their long-term prosperity prospects. Increased migration to coastal areas and increased exposure to extreme climatic events indicates a need for social and economic data to inform socio-ecological systems planning. Here, we undertake a geo-spatial analysis to develop a typology of Australian coastal communities and assess relative vulnerability to climate-driven environmental change for a range of social and economic indicators. The aim of this study is to understand how the vulnerability of Australian coastal communities varies with geographic location or community size, and in comparison to other community types. Results show that both the population size and location of a coastal community matter and that coastal communities overall are more vulnerable on some socio-economic dimensions to climate-driven environmental change than their rural equivalents. However, results also demonstrate that the smallest coastal communities are strong in some important aspects of the human, social and financial domains, putting them in a good position to deal with some changes. Scale-appropriate and context-specific social policies are needed to address identified socio-economic vulnerabilities, supported by a range of formal and informal institutional structures, such as strategies to improve education and female workforce participation, and encourage participation in volunteering to increase human and social capital.

Late Cenozoic submarine slope failures in the southern North Sea – Evolution and controlling factors

During the Late Miocene to early Pleistocene sedimentation in the southern North Sea Basin was dominated by a westward prograding depositional system. Progradation is evidenced by a series of large-scale, westward dipping clinoforms with amplitudes of up to 400 m. The clinoforms are related to a shelf-slope-basin physiography during deposition and their development and growth reflects the basinward migration of the Late Cenozoic shelf margin through time. Numerous submarine slope failures occurred on the shelf margin during this time, recognized as kilometer-scale mass-transport deposits (MTDs). Comparatively little is known about the earliest slope failures on this prograding shelf margin, yet their role is important in developing a coherent understanding of the origins of the instability of the margin as a whole. In this study we present detailed analyses of the first MTDs occurring on this Late Cenozoic shelf margin. Based on interpretation of 2D seismic reflection profiles, borehole data and integration of new chronostratigraphic datings the development and causes of slope instabilities are reconstructed. Three MTDs are distinguished within the German part of the southern North Sea, one (MTD1) that has been displaced in the Late Tortonian and two (MTD 2/3) in the Piacenzian. MTD 1 was triggered by salt-induced seismicity, as evident from salt-related faulting of the Late Cenozoic succession in its headwall domain. Pore pressure build up due to fluid migration from deeper levels in combination with loading imposed to the basin by the prograding shelf prism are the main factors controlling the initiation of MTDs 2 and 3.Subsequent slope failures occurring during shelf progradation within the Dutch North Sea are much more frequent compared to the earliest slope failures. The development from a relatively stable shelf margin towards a margin affected by repeated slope failures coincides approximately with the intensification of Northern Hemisphere Glaciations during Pleistocene times. The development and deposition of the MTDs in the Dutch North Sea is clearly linked to climate-driven environmental changes, whereas prior to the Pleistocene failure mechanisms are preferably limited to those independent of glaciations and associated sea level changes and therefore fewer failures have occurred.

Changes in seasonal climate outpace compensatory density-dependence in eastern brook trout.

Understanding how multiple extrinsic (density-independent) factors and intrinsic (density-dependent) mechanisms influence population dynamics has become increasingly urgent in the face of rapidly changing climates. It is particularly unclear how multiple extrinsic factors with contrasting effects among seasons are related to declines in population numbers and changes in mean body size and whether there is a strong role for density-dependence. The primary goal of this study was to identify the roles of seasonal variation in climate driven environmental direct effects (mean stream flow and temperature) vs. density-dependence on population size and mean body size in eastern brook trout (Salvelinus fontinalis). We use data from a 10-year capture-mark-recapture study of eastern brook trout in four streams in Western Massachusetts, USA to parameterize a discrete-time population projection model. The model integrates matrix modeling techniques used to characterize discrete population structures (age, habitat type, and season) with integral projection models (IPMs) that characterize demographic rates as continuous functions of organismal traits (in this case body size). Using both stochastic and deterministic analyses we show that decreases in population size are due to changes in stream flow and temperature and that these changes are larger than what can be compensated for through density-dependent responses. We also show that the declines are due mostly to increasing mean stream temperatures decreasing the survival of the youngest age class. In contrast, increases in mean body size over the same period are the result of indirect changes in density with a lesser direct role of climate-driven environmental change.

Climate changes in mangrove forests and salt marshes

Abstract This synthesis is framed within the scope of the Brazilian Benthic Coastal Habitat Monitoring Network (ReBentos WG 4: Mangroves and Salt Marshes), focusing on papers that examine biodiversity-climate interactions as well as human-induced factors including those that decrease systemic resilience. The goal is to assess difficulties related to the detection of climate and early warning signals from monitoring data. We also explored ways to circumvent some of the obstacles identified. Exposure and sensitivity of mangrove and salt marsh species and ecosystems make them extremely vulnerable to environmental impacts and potential indicators of sea level and climate-driven environmental change. However, the interpretation of shifts in mangroves and salt marsh species and systemic attributes must be scrutinized considering local and setting-level energy signature changes; including disturbance regime and local stressors, since these vary widely on a regional scale. The potential for adaptation and survival in response to climate change depends, in addition to the inherent properties of species, on contextual processes at the local, landscape, and regional levels that support resilience. Regardless of stressor type, because of the convergence of social and ecological processes, coastal zones should be targeted for anticipatory action to reduce risks and to integrate these ecosystems into adaptation strategies. Management must be grounded on proactive mitigation and collaborative action based on long-term ecosystem-based studies and well-designed monitoring programs that can 1) provide real-time early warning and 2) close the gap between simple correlations that provide weak inferences and process-based approaches that can yield increasingly reliable attribution and improved levels of anticipation.

Climate-driven environmental changes around 8,200 years ago favoured increases in cetacean strandings and Mediterranean hunter-gatherers exploited them.

Cetacean mass strandings occur regularly worldwide, yet the compounded effects of natural and anthropogenic factors often complicate our understanding of these phenomena. Evidence of past stranding episodes may, thus, be essential to establish the potential influence of climate change. Investigations on bones from the site of Grotta dell’Uzzo in North West Sicily (Italy) show that the rapid climate change around 8,200 years ago coincided with increased strandings in the Mediterranean Sea. Stable isotope analyses on collagen from a large sample of remains recovered at this cave indicate that Mesolithic hunter-gatherers relied little on marine resources. A human and a red fox dating to the 8.2-kyr-BP climatic event, however, acquired at least one third of their protein from cetaceans. Numerous carcasses should have been available annually, for at least a decade, to obtain these proportions of meat. Our findings imply that climate-driven environmental changes, caused by global warming, may represent a serious threat to cetaceans in the near future.

Environmental change and human occupation of southern Ethiopia and northern Kenya during the last 20,000 years

Our understanding of the impact of climate-driven environmental change on prehistoric human populations is hampered by the scarcity of continuous paleoenvironmental records in the vicinity of archaeological sites. Here we compare a continuous paleoclimatic record of the last 20 ka before present from the Chew Bahir basin, southwest Ethiopia, with the available archaeological record of human presence in the region. The correlation of this record with orbitally-driven insolation variations suggests a complex nonlinear response of the environment to climate forcing, reflected in several long-term and short-term transitions between wet and dry conditions, resulting in abrupt changes between favorable and unfavorable living conditions for humans. Correlating the archaeological record in the surrounding region of the Chew Bahir basin, presumably including montane and lake-marginal refugia for human populations, with our climate record suggests a complex interplay between humans and their environment during the last 20 ka. The result may contribute to our understanding of how a dynamic environment may have impacted the adaptation and dispersal of early humans in eastern Africa.

Foraging behavior links climate variability and reproduction in North Pacific albatrosses.

BackgroundClimate-driven environmental change in the North Pacific has been well documented, with marked effects on the habitat and foraging behavior of marine predators. However, the mechanistic linkages connecting climate-driven changes in behavior to predator populations are not well understood. We evaluated the effects of climate-driven environmental variability on the reproductive success and foraging behavior of Laysan and Black-footed albatrosses breeding in the Northwest Hawaiian Islands during both brooding and incubating periods. We assessed foraging trip metrics and reproductive success using data collected from 2002–2012 and 1981–2012, respectively, relative to variability in the location of the Transition Zone Chlorophyll Front (TZCF, an important foraging region for albatrosses), sea surface temperature (SST), Multivariate ENSO Index (MEI), and the North Pacific Gyre Oscillation index (NPGO).ResultsForaging behavior for both species was influenced by climatic and oceanographic factors. While brooding chicks, both species traveled farther during La Niña conditions, when NPGO was high and when the TZCF was farther north (farther from the breeding site). Models showed that reproductive success for both species showed similar trends, correlating negatively with conditions observed during La Niña events (low MEI, high SST, high NPGO, increased distance to TZCF), but models for Laysan albatrosses explained a higher proportion of the variation. Spatial correlations of Laysan albatross reproductive success and SST anomalies highlighted strong negative correlations (>95 %) between habitat use and SST. Higher trip distance and/or duration during brooding were associated with decreased reproductive success.ConclusionsOur findings suggest that during adverse conditions (La Niña conditions, high NPGO, northward displacement of the TZCF), both Laysan and Black-footed albatrosses took longer foraging trips and/or traveled farther during brooding, likely resulting in a lower reproductive success due to increased energetic costs. Our results link climate variability with both albatross behavior and reproductive success, information that is critical for predicting how albatross populations will respond to future climate change.

Building Resilience Against Climate-Driven Shifts in a Temperate Reef System: Staying Away from Context-Dependent Ecological Thresholds

As climate-driven environmental changes and anthropogenic perturbations increasingly affect ecological systems, the number of abrupt phase shifts in ecosystem dynamics is rising, with far-reaching ecological, economic and social effects. These shifts are notoriously difficult to study, anticipate and manage. Although indicators of impending phase shifts in ecosystems have been described theoretically, they have only been observed empirically either after the fact or under controlled experiments. Here we demonstrate the usefulness of case-specific simulation models to estimate tipping points in the dynamics of real ecological systems, characterise how these thresholds may vary depending on local conditions and derive safe management targets associated with low risk of undesirable phase shifts. Under the combined effects of ocean changes and fishing, inshore rocky reefs in eastern Tasmania can transition from dense seaweed beds to sea urchin ‘barrens’ habitat, realising severe local loss of habitat, productivity and valuable fisheries. Using Monte-Carlo simulations with a validated model that realistically captures reef dynamics, we characterise the hysteresis in community dynamics and the variability in ecological thresholds along the gradient of environmental conditions. Simulation suggests that prevention of ongoing sea urchin destructive grazing of macroalgal beds is achievable but the yet-to-be-observed restoration of seaweed beds from extensive sea urchin barrens is highly unlikely. To guide management against undesirable phase shifts, we define target points associated with low risk of widespread barrens formation and show that, along with sea urchin culling, recognising the role of lobsters in mitigating sea urchin destructive grazing through predation is key to maintain reef productivity.

Energy flow and functional compensation in Great Basin small mammals under natural and anthropogenic environmental change

Research on the ecological impacts of environmental change has primarily focused at the species level, leaving the responses of ecosystem-level properties like energy flow poorly understood. This is especially so over millennial timescales inaccessible to direct observation. Here we examine how energy flow within a Great Basin small mammal community responded to climate-driven environmental change during the past 12,800 y, and use this baseline to evaluate responses observed during the past century. Our analyses reveal marked stability in energy flow during rapid climatic warming at the terminal Pleistocene despite dramatic turnover in the distribution of mammalian body sizes and habitat-associated functional groups. Functional group turnover was strongly correlated with climate-driven changes in regional vegetation, with climate and vegetation change preceding energetic shifts in the small mammal community. In contrast, the past century has witnessed a substantial reduction in energy flow caused by an increase in energetic dominance of small-bodied species with an affinity for closed grass habitats. This suggests that modern changes in land cover caused by anthropogenic activities--particularly the spread of nonnative annual grasslands--has led to a breakdown in the compensatory dynamics of energy flow. Human activities are thus modifying the small mammal community in ways that differ from climate-driven expectations, resulting in an energetically novel ecosystem. Our study illustrates the need to integrate across ecological and temporal scales to provide robust insights for long-term conservation and management.

Drainage development, neotectonics and base-level change in the Kalahari Desert, southern Africa

The Kalahari Desert contains extensive networks of ephemeral and fossil drainage which are potential indicators of past and present neotectonic activity and climate-driven environmental change. An absence of topographic data has hindered our understanding of their development. We present long-profile information for twenty-nine valley networks derived from Shuttle Radar Topographic Mission (SRTM) digital elevation data. In total, 8354 km of valley talweg was measured for x, y and z information. Most valleys exhibit concave-up profiles. Fifty-five previously unknown knickpoints were identified. The majority coincide with lithological boundaries or fractures, but many developed in response to Neogene uplift and/or downwarping or occur where valleys cross palaeolake shorelines. The headwaters of four valleys cross the Kalahari–Limpopo drainage divide and predate the presumed Miocene uplift of the Kalahari–Zimbabwe axis, suggesting that they are of considerable antiquity.

Differential responses of marine communities to natural and anthropogenic changes.

Responses of ecosystems to environmental changes vary greatly across habitats, organisms and observational scales. The Quaternary fossil record of the Po Basin demonstrates that marine communities of the northern Adriatic re-emerged unchanged following the most recent glaciation, which lasted approximately 100,000 years. The Late Pleistocene and Holocene interglacial ecosystems were both dominated by the same species, species turnover rates approximated predictions of resampling models of a homogeneous system, and comparable bathymetric gradients in species composition, sample-level diversity, dominance and specimen abundance were observed in both time intervals. The interglacial Adriatic ecosystems appear to have been impervious to natural climate change either owing to their persistence during those long-term perturbations or their resilient recovery during interglacial phases of climate oscillations. By contrast, present-day communities of the northern Adriatic differ notably from their Holocene counterparts. The recent ecosystem shift stands in contrast to the long-term endurance of interglacial communities in face of climate-driven environmental changes.

Cyanobacterial diversity in benthic mats of the McMurdo Dry Valley lakes, Antarctica

Perennially ice-covered, meromictic lakes in the McMurdo Dry Valleys, Antarctica, are useful models to study the relationship between cyanobacterial and environmental variables. They have rich benthic cyanobacterial mat accumulations and stable stratification of physical and chemical conditions. Here, we evaluated cyanobacteria from benthic mats from multiple depths in three geographically separated ice-covered lakes, Lakes Vanda, Hoare and Joyce, using 16S rRNA gene clone libraries. We identified 19 ribotypes, mostly Oscillatoriales and several Chroococcales, as well as potentially novel cyanobacterial ribotypes. The majority of ribotype diversity was shared between lakes, and only a weak relationship between ribotype community structure and environmental variables was evident. Multivariate analysis of all lake–depth combinations implied that photosynthetically active radiation, dissolved reactive phosphorus and conductivity were potentially important for shaping benthic communities in McMurdo Dry Valley lakes. Cyanobacterial-specific pigment signature analysis by high-performance liquid chromatography showed that the cyanobacterial communities responded to light conditions similarly, irrespective of community composition. The results imply a capability within a suite of cyanobacteria to colonise, adapt and grow across broad environmental ranges and geographic space, and such adaptability may provide a high degree of community resistance and resilience to future climate-driven environmental change in Antarctic terrestrial aquatic ecosystems.

English

This is the second year of our three-year pilot project designed to identify the potential significance of the Quaternary sedimentary record of the upper catchment of the Kura river in northeastern Turkey. Our overall aim is to understand the evolution of the Kura catchment during the last 2.5 million years within the context of dramatic regional tectonic and climate-driven environmental changes. Specifically, we want to assess the importance of the Kura river valley as a potential migration pathway for early hominins from Asia into Europe. Based upon our earlier BIAA-funded research in western Turkey, we now believe the earliest securely-dated hominins in western Turkey arrived sometime around 1.2 million years ago (Maddy et al. in review; also Lebatard et al. 2014). However, it is likely that hominins roamed across the Kura catchment much earlier, especially as early hominins (H. erectus ergaster georgicus; see Lordkipanidze et al. 2013) arrived at Dminisi in Georgia around 1.8–1.6 million years ago (Gabunia et al. 2000). The timing of these early arrivals relies on finding hominin remains or artefacts within securely-dated sedimentary deposits. Establishing a reliable stratigraphy and chronology for the sedimentary and volcanic sequence in the Kura catchment will take many years, but this pilot study will inform our future work programme, allowing the targeting of key areas of interest, thus helping to make future research more efficient and effective. Our first field season identified a number of immediate areas of interest, and during our second visit we concentrated our efforts in one of these areas, focusing on surface mapping and the description of outcrops close to the village of Sevimli. Our initial work in this area, northwest of the village, identified the possible occurrence of three high-level river terraces buried beneath basaltic lava flows flanking the deeply incised (>140m) narrow modern valley. However, observations were limited to one surface exposure in the underlying sediments, restricting confirmation of a fluvial origin to only one of these terrace levels. We sampled the overlying basalts for Ar-Ar age estimation last year, but these samples are currently being analysed, with results due later this year. Significantly, however, the terrace sequence is cross-cut by a large NNE–SSW trending normal fault, downstream (east) of which the terraces appear vertically offset (downwards) by up to 80m relative to those upstream (west), suggesting substantial post-depositional fault movement along this fault. This fault is one of many similar trending faults to cut across this part of the Kura valley. These faults form part of a series of structures which transfer strike-slip motion from the Dursunlu fault system (which forms the western limit of the Ardahan basin) eastwards across to the large Kura fault system which extends northwards into Georgia. This strike slip motion is believed to be coeval with the onset of motion along the north Anatolian fault system and thus begins around 7 million years ago, which constrains a maximum age for the higher terrace sequence. It is likely, however, that these terraces are much younger, a question we should be able to answer once we receive the outcome of the Ar-Ar age estimation from these lavas. This year we focused on the area south of the Kura incised valley, where a small northward draining tributary has cut a small canyon, exposing, in places, the sediments beneath the overlying lava flows. Our field observations when combined with detailed survey of the outcrops, obtained using a Pentax total station, suggest the presence of up to six terraces above the level of the modern incised

Microsatellite markers for the Arctic copepod Calanus glacialis and cross-amplification with C. finmarchicus

Calanus glacialis is a major component of Arctic zooplankton and a keystone species in Arctic marine ecosystems. Due to the observed climate warming, its numbers are being reduced to the advantage of a sibling Atlantic species Calanus finmarchicus. We developed and characterized the first set of microsatellite markers in this species to investigate its population genetic structure and dispersal capabilities. Nine polymorphic loci displayed an average of 7.3 alleles (range between 2 and 13) and the levels of expected heterozygosity ranged from 0.039 to 0.806. These provide a valuable tool to understand present connectivity patterns across Arctic regions, look for signatures of past climate effects and predict the response to future climate-driven environmental changes. Additionally, due to the cross-amplification with C. finmarchicus, the markers can be used to discriminate between these sibling species.

Agent-Based Simulation of Holocene Monsoon Precipitation Patterns and Hunter-Gatherer Population Dynamics in Semi-arid Environments

Based on archaeological evidence from Kutch-Saurashtra (N Gujarat, NW India), we use agent-based modelling (ABM) to explore the persistence of hunter-gatherer (HG) groups in semi-arid environments in the mid and late Holocene. Agents interact within a realistic semi-arid environment dominated by the monsoon. Precipitation trends are modelled from instrumental records (1871–2008) calibrated with existing models for the Asian monsoon in the Holocene (c. 12 ka–present). Experiments aim at exploring dependencies between population dynamics and climate-driven environmental change (in terms of resource availability) for precipitation patterns at the local, regional and continental scales. Resources are distributed across a simplified ground model. Average yearly precipitation (AYP, i.e. mean) and variance in yearly precipitation (VYP, i.e. standard deviation) are the main parameters affecting resource availability in the simulations. We assess the effects of environmental change on HG populations at different timescales: (1) patterns of seasonal (inter-annual) resource availability, (2) effects of changes in mean precipitation trends over the long (Pleistocene–Holocene) and the mid (Holocene, millennial) periods, and (3) effects of intra-annual precipitation variability, i.e. changes in standard deviation from mean precipitation trends over the short period (annual to decadal). Simulations show that (1) strong seasonality is coherent with the persistence of HG populations in India, independently of the geographical scale of the precipitation models, (2) changes in AYP over the mid period (Holocene) are not sufficient to explain the disappearance of HG populations in Kutch-Saurashtra (K-S) 4 ka and (3) precipitation variability (VYP) over the short period (annual to decadal) is the main parameter affecting population performance and overall ecosystem dynamics. To date, sufficiently refined palaeoclimatic records do not exist for the study area, but higher VYP values 4 ka do not exclude the possibility that other factors may have driven the disappearance of HG populations in Kutch-Saurashtra.

Public health and livestock: Emerging diseases in food animals

Despite public health and veterinary public health improvements within the past century, human and animal populations remain vulnerable to health threats caused by infectious diseases. Noticeably, the rate of emerging infectious diseases is increasing (one new emerging or re-emerging disease every eight months). Meanwhile, many endemic diseases have increased in incidence. Out of 1,400 microbes that could cause human infections, more than 60% are also pathogenic for wild or domestic animals (OIE, 2012). These zoonotic agents cause 75% of human emerging infections (OIE, 2012). Since they can be contagious to humans or compromise the food safety, the infectious diseases of animals represent a direct public health issue (OIE, 2012). They also carry an indirect threat since they account for the majority of the 20% losses that affect the livestock sector at the production level and since they could severely hamper the animal traction resources that are needed to produce or transport goods. These losses raise an issue of food security to sustain an increasing demand for proteins of animal origin. By 2020, the livestock sector is expected to represent 50% of the agriculture outputs in value. In developing countries, uncontrolled re-emergence of infectious diseases threatens the main asset of families, thus preventing them to escape from poverty. Additionally, the animal morbidity and mortality generated by infections represent an unjustified emission of greenhouse gases, thus raising an environmental issue. In a growing number of countries, infections are also perceived as a primary concern for animal welfare. The rapid pace of infection emergence is not only connected to more suitable conditions for pathogen appearance and spreading, it is also linked to improved methods and technologies for surveillance, pathogen detection, and identification. There are all kinds of pathogen agents of concern: prion, viruses, bacteria, and mono-cellular and pluri-cellular parasites. Several drivers of infectious diseases have been identified, many of which are of anthropogenic origin: i) Indeed, the role of the expansion and intensification of animal agriculture has been pointed out. Changes in nutritional and agricultural practices, associated to the second livestock revolution (1980s through 1990s), have led to intensive production systems, the frequent use of antimicrobial agents, high densities of animals with suboptimal husbandry conditions, and a decline in genetic diversity. ii) The ongoing global change and the resulting climate-driven environmental change, as well as natural disasters, have introduced ecological perturbations and flux shifts into finely tuned ecosystems consisting, for example, in modified interactions between pathogen vectors and hosts. iii) The population growth, associated with a facilitated access to travel means, has a strong impact. Socio-economical determinants such as political instability and the resulting migrations should be emphasized. iv) Fast and large-range trade of animal and food products have a major influence. Various kinds of changes in food-processing practices were also strongly influential. v) Several shifts in land use should be mentioned such as: accelerated urbanization, deforestation, and the encroachment on wildlife with extensive and closer contacts among humans, livestock animals, and wildlife. Species barriers crossing often occur at ecological interfaces. vi) Finally, it should be stressed that countries where a capacity breakdown occurs in the domains of public health and animal health management, become a weak link in the global effort to prevent, detect, and respond to disease outbreaks. Moreover, poor socio-economic conditions are generally associated with closer contacts between humans and animals, as well as greater exposure to vectors, thus increasing the risk of disease emergence in these countries.

Archeological and environmental lessons for the Anthropocene from the Classic Maya collapse

Abstract The original formulation of the “Anthropocene” emphasized the global environmental change resulting from expanding human populations and fossil fuel burning since the industrial revolution of the late 18th century. Politically, the message is that scientists and engineers should work toward an internationally accepted sustainable future. This assumes, and is dependent upon, maintaining the integrity of our increasingly interconnected social, economic, and political systems worldwide. Anthropogenic environmental change and degradation (e.g., global warming, sea-level rise, erosion) within the context of the Anthropocene has the potential to displace populations, undermine food security and human health, stimulate conflict, and destabilize social, economic and political systems. Ultimately, we do not know if our political systems could withstand these forces or whether degradation would lead to increased war and further environmental degradation. We can, however, study the complex processes of political collapse retrospectively in the archeological and historical records. In this paper, we examine one such predecessor in world history, the widespread collapse of Classic Maya polities within the context of anthropogenic and climate-driven environmental change between AD 600 and 1000. We conclude that the staggered collapse of inter-connected and rigidly organized political centers ultimately resulted from multiple drivers including anthropogenic and climate-driven environmental change. Any way one looks at Maya history suggests a precursor toward the Anthropocene: greatly changed forests and soils, water management and food production, population increase and aggregation, and even alteration of local hydrology and climate caused by deforestation and wetland manipulation.

Variation in δ15N of a lacustrine sedimentary sequence in the Nanling Mountains and its potential implication for climatic conditions over the past ∼16 000 years

Although extensive studies have been performed on nitrogen isotopes in lake sediments, understanding the complexity of the δ15N variation related to past environmental and climatic conditions still remains unclear. Supported by multi-proxy records including litho-units, organic carbon isotopes, ration of total organic carbon and total nitrogen, organic matter content, bulk dry density, the accumulation rate of organic matter, median grain size, magnetic susceptibility, and Rb/Sr and Ca/Mg ratios obtained from a sedimentary sequence in a small lake (i.e., Dahu Swamp) in the eastern Nanling Mountains in South China, we deduce that variation in the δ15N values results primarily from the sources of organic matter, which are significantly influenced by climatic conditions over the past ∼16 000 years. A low (or high) lake level resulting from dry (or wet) conditions would lead to more (or fewer) vascular plant remains in the sediments and stronger (or weaker) denitrification associated with hypolimnetic anoxia, resulting in lower (or higher) δ15N values. In addition, dry (or wet) conditions would favor weakened (or strengthened) biogeochemical activity in the catchment, which could result in less (or more) external input of 15N-enriched OM, thus leading to decreased (or increased) δ15N values. Our results indicate that the lake sediment δ15N record in the Nanling Mountains has the potential to provide valuable insight into past East Asian monsoon climatedriven environmental changes.

Beyond the core: community governance for climate-change adaptation in peripheral parts of Pacific Island Countries

Pacific Island Countries are highly exposed to climate change. Most impact studies have focused on the most densely populated core areas where top-down governance is most effective. In contrast, this research looks at peripheral (rural/outer-island) communities where long-established systems of environmental governance exist that contrast markedly with those which governments and their donor partners in this region favour. Peripheral communities in the Cook Islands, Fiji, Kiribati, and Vanuatu were studied. Traditional systems of environmental governance are described, and three common barriers to effective and sustainable climate-change adaptation identified. The first is lack of awareness among key community decision makers about climate change and associated environmental sustainability that could be lessened by targeted awareness raising. The second is the inappropriateness of traditional decision-making structures for dealing with both the complexity and pace of climate-driven environmental changes. The third is the short-term views of resource management and sustainability held by many community decision makers. Despite 30 years of assistance, there has been negligible effective and sustainable adaptation for climate change in peripheral parts of Pacific Island Countries, something that is explicable by both the ineffectiveness of top-down approaches in such places as well as a lack of attention to the nature and the context of adaptation communications. It is timely for interventions to be made at community level where the greatest disconnect lies between the science and stakeholder awareness of climate change.