Rapid Landscape Change Research Articles

Hillslope‐Channel Transitions and the Role of Water Tracks in a Changing Permafrost Landscape

AbstractThe Arctic is experiencing rapid climate change, and the effect on hydrologic processes and resulting geomorphic changes to hillslopes and channels is unclear because we lack quantitative models and theory for rapid changes resulting from thawing permafrost. The presence of permafrost modulates water flow and the stability of soil‐mantled slopes, implying that there should be a signature of permafrost processes, including warming‐driven disturbance, in channel network extent. To inform understanding of hillslope‐channel dynamics under changing climates, we examined soil‐mantled hillslopes within a ∼300 km2 area of the Seward Peninsula, western Alaska, where discontinuous permafrost is particularly susceptible to thaw and rapid landscape change. In this study, we pair high‐resolution topographic and satellite data to multi‐annual observations of InSAR‐derived surface displacement over a 5‐year period to quantify spatial variations in topographic change across an upland landscape. We find that neither the basin slope nor the presence of knickzones controls the magnitude of recent surface displacements within the study basin, as may be expected under conceptual models of temperate hillslope evolution. Rather, the highest displacement magnitudes tended to occur at the broad hillslope‐channel transition zone. In this study area, this zone is occupied by water tracks, which are zero‐order ecogeomorphic features that concentrate surface and subsurface flow paths. Our results suggest that water tracks, which appear to occupy hillslope positions between saturation and incision thresholds, are vulnerable to warming‐induced subsidence and incision. We hypothesize that gullying within water tracks will outpace infilling by hillslope processes, resulting in the growth of the channel network under future warming.

Meandering river evolution in an unvegetated permafrost environment

Meandering river sedimentary facies are associated with the rise of terrestrial vegetation in the rock record, but modern examples of highly sinuous, single-threaded streams are also found in many modern non-vegetated environments. Prior workers have speculated that permafrost or ice-cemented sediment could provide the cohesion needed to generate single-threaded, meandering channels, however, the presence of bank vegetation in the overwhelming majority of terrestrial permafrost sites in which meandering rivers are present has made it impossible to disentangle the relative impact of bank cohesion provided by frozen sediments from that provided by roots. Here, we examine topographic change over 13 years at the Onyx River, an unvegetated, permafrost-affected, sand-and-gravel-bottomed river in the McMurdo Dry Valleys (MDV) of Antarctica, supported by ∼40 years of image data. On the basis of lidar change detection and satellite/airborne image analysis, we find that meandering river processes (cut bank erosion, point bar growth, and meander migration) can occur in this ice-cemented, unvegetated permafrost river system. We find that the Onyx River's upper, single-threaded reach is meandering, and that bank cohesion is provided by ice-cemented permafrost. Meander migration rates within the Onyx's meandering reach are extremely close to values predicted based on observations of meander migration rates in other unvegetated rivers, however, the short (∼70 day) duration of Onyx River discharge suggests these migration rates should be considered low estimates, which could be up to ∼5 times greater during the short, summer erosion season. Together, these observations suggest that ice-cemented permafrost is a weak form of bank cohesion that can result in rapid landscape change in response to thermokarstic fluvial erosion, producing dynamic river channels, especially where warm meltwater encounters ice-rich permafrost deposits.

Spatial variations in ground surface temperature at various scales on the northeastern Qinghai-Tibet Plateau, China

Ground surface temperature (GST, depth of 5 cm) is essential for understanding the climate-induced impacts in the Earth Critical Zone, especially in cold regions. This work aims to detect the GST variability from fine (2 to 16 m) to local and landscape scales (2 and 50 km2) and along an 800-m elevational transect. The study area is located in the southern part of the Headwater Area of the Yellow River (HAYR), a representative area of discontinuous alpine permafrost on northeastern Qinghai-Tibet Plateau. From 2019 to 2020, GST was recorded at 39 sites under similar and varied environmental conditions. A statistically significant correlation was identified between mean annual GST (MAGST) with landcover (0.37, p < 0.05) and elevation (−0.76, p < 0.001). The analysis of variance (ANOVA) showed significant differences in MAGST between sites on bare ground and with vegetation. At the local/landscape scales, MAGSTs in meadows (−0.6 to 0.6 °C) were higher than those in swamp meadows (−1.4 to 0.7 °C) and bare grounds (−2.0, − 1.2 °C). At the fine scale, GST revealed a high similarity between plots (R2 > 0.95 for 90 % of the sites) but with an RMSE ranging from 0.25 to 1.5 °C. The intra-plot difference in MAGST was below 0.5 °C for sites with similar landcover in both plots and up to 1–2 °C when vegetation was compared to the bare ground. The decrease of MAGST with rising elevation was more pronounced for the sites in bare ground (R2 = 0.83, p < 0.001) than vegetated ones (e.g., meadow: R2 = 0.64, p < 0.003). These results help identify the patterns of permafrost distribution and thaw at a high spatial resolution and better understand their relationship with vegetation development, soil organic carbon, and the rapid landscape changes in the HAYR.

From data to interpretable models: machine learning for soil moisture forecasting

Soil moisture is critical to agricultural business, ecosystem health, and certain hydrologically driven natural disasters. Monitoring data, though, is prone to instrumental noise, wide ranging extrema, and nonstationary response to rainfall where ground conditions change. Furthermore, existing soil moisture models generally forecast poorly for time periods greater than a few hours. To improve such forecasts, we introduce two data-driven models, the Naive Accumulative Representation (NAR) and the Additive Exponential Accumulative Representation (AEAR). Both of these models are rooted in deterministic, physically based hydrology, and we study their capabilities in forecasting soil moisture over time periods longer than a few hours. Learned model parameters represent the physically based unsaturated hydrological redistribution processes of gravity and suction. We validate our models using soil moisture and rainfall time series data collected from a steep gradient, post-wildfire site in southern California. Data analysis is complicated by rapid landscape change observed in steep, burned hillslopes in response to even small to moderate rain events. The proposed NAR and AEAR models are, in forecasting experiments, shown to be competitive with several established and state-of-the-art baselines. The AEAR model fits the data well for three distinct soil textures at variable depths below the ground surface (5, 15, and 30 cm). Similar robust results are demonstrated in controlled, laboratory-based experiments. Our AEAR model includes readily interpretable hydrologic parameters and provides more accurate forecasts than existing models for time horizons of 10–24 h. Such extended periods of warning for natural disasters, such as floods and landslides, provide actionable knowledge to reduce loss of life and property.

Integrating Spatial Modelling and Interpolation of Environmental Factors in Landscape Design Analysis

Rapid landscape change for physical development has led to extensive environmental consequences. Analysing and simulating landscape change's impact is vital in understanding the consequence of existing development scenarios, particularly on the microclimate and thermal comfort. Spatial interpolation is one of the tools capable of visualising the characteristic of the environmental scenario in any area with empirical data. This paper discussed the method of GIS integration in modelling the environmental characteristic (microclimate) in landscape design development. A spatial database is developed based on the input from empirical data, and IDW is used to simulate the environmental characteristic of the landscape in the analysis stage. Using campus landscape rehabilitation at UTMKL Pasir Gudang as an example, an empirical study was conducted to collect the microclimate data and the existing landscape composition. Both existing and future microclimate situations are visualised and simulated to strengthen the understanding of the functionality of the new landscape design proposal. It indicates the performance of the landscape design and demonstrates the thermal comfort level of the campus. This analysis goes beyond aesthetic value evaluation and gives designers the necessary idea to orientate the ideal design concept to optimise ecosystem service to the campus. The spatial interpolation clearly shows the expected environmental condition scenario as the landscape at the campus changes. This simulation significantly improves the decision-making process in landscape design that contributes to an eco-friendly campus where the community will have a more comfortable environment. In conclusion, the spatial interpolation of the environmental characteristic is vital to formulate a substantial understanding of the landscape design consequence to maximise ecosystem service provision.

Remotely sensed time series of rapid terrace formation: Laguna del Viedma valley (Patagonia)

The Patagonian Andes were affected by a range of geophysical drivers of landscape incision during the Last Glacial Interglacial Transition and Early Holocene. Deciphering drivers of river system response during this period is complex, and magnitudes and timescales of landscape change are poorly constrained. Herein, a remotely sensed time series of modern terrace formation is investigated from the Laguna del Viedma valley as a modern analogue of Late Quaternary landscape evolution in Patagonia. The aim of the research was to constrain the timing of terrace formation following lake level fall of the Laguna del Viedma over a 35 year period from 1985-2019. The objectives were to: 1) use satellite imagery from 1985-2019 to document glacier and lake changes in the study area; 2) map landforms of the Laguna del Viedma valley; and 3) analyse terrace elevations. In total seven terrace surfaces were distinguished, with the oldest four pre-dating the ALOS PALSAR DEM (February 2000) used. Landform evidence shows the highest, and vegetated, T1 terrace surface (+40-75 m) grades to the highest lake level and was likely the elevation of the valley floor during Holocene neoglacials. Viedma glacier recession then led to a phase of lake regressions/transgressions with an overall trend of lake level fall. The DEM shows ~20 m incision from the 1985 floodplain level (T3) to the T4 level floodplain by 2000. This constrains a minimum rate of incision of 1.33 m/yr, however, the satellite time series demonstrates rapid T3 terrace formation, with evidence for mass movements contributing to lateral terrace erosion by 1986. The implications of the data are discussed within the context of the Late Quaternary palaeohydrology of Patagonia where lake level falls of 10s to 100s of metres occurred within many large river systems of the Patagonian Andes from 42-52⁰ S. The data herein demonstrate that base level falls from sudden lake drainage events were likely a major driver of rapid landscape change in Patagonia during deglaciation.

Ecological and Wildfire Responses to Rapid Landscape Changes within the Last ~900 Years on the South Haven Peninsula, Dorset (Southern England)

A multi-proxy palaeoenvironmental dataset (LOI, pollen, charcoal, grain sizes and the humification index) was extracted and radiocarbon dated from a sedimentary sequence from Spur Bog, central South Haven Peninsula (Dorset, southern England) to reconstruct ecological and environmental changes within the last ~900 years. These analyses reveal highly unstable environmental conditions at the site, evidencing the occurrence of multiple, often rapid changes during this period. The results significantly expand upon the existing palaeoenvironmental and geomorphological frameworks of the South Haven Peninsula which previously relied upon sparse, vague historical records prior to ~1750 AD. The multi-proxy dataset of Spur Bog sediments recorded a primary “development” phase (~1150–1470 AD) during which marine processes were the dominant control upon environmental conditions at the site, resulting in marked geomorphological changes that lead to the progressive eastward expansion of the South Haven Peninsula. This is followed by a secondary “maturation” phase (~1470–1880 AD) during which the Spur Bog sequence exhibits significant ecological changes in response to fluctuations in sea level, coastal erosion and human activity, demonstrating the vulnerability of the site to future climatic and anthropogenic pressures.

Landscape of stress: Tree mortality influences physiological stress and survival in a native mesocarnivore.

Climate change and anthropogenic modifications to the landscape can have both positive and negative effects on an animal. Linking landscape change to physiological stress and fitness of an animal is a fundamental tenet to be examined in applied ecology. Cortisol is a glucocorticoid hormone that can be used to indicate an animal’s physiological stress response. In the Sierra Nevada Mountains of California, fishers (Pekania pennanti) are a threatened mesocarnivore that have been subjected to rapid landscape changes due to anthropogenic modifications and tree mortality related to a 4-year drought. We measured cortisol concentrations in the hair of 64 fishers (41 females, 23 males) captured and radio-collared in the Sierra National Forest, California. We addressed two main questions: (1) Is the physiological stress response of fishers influenced by anthropogenic factors, habitat type, canopy cover, and tree mortality due to drought in their home range? (2) Does the physiological stress response influence survival, reproduction, or body condition? We examined these factors within a fisher home range at 3 scales (30, 60, 95% isopleths). Using model selection, we found that tree mortality was the principle driver influencing stress levels among individual fishers with female and male fishers having increasing cortisol levels in home ranges with increasing tree mortality. Most importantly, we also found a link between physiological stress and demography where female fishers with low cortisol levels had the highest annual survival rate (0.94), whereas females with medium and high cortisol had lower annual survival rates, 0.78 and 0.81, respectively. We found no significant relationships between cortisol levels and body condition, male survival, or litter size. We concluded that tree mortality related to a 4-year drought has created a “landscape of stress” for this small, isolated fisher population.

Long-term climate-influenced land cover change in discontinuous permafrost peatland complexes

Abstract. The discontinuous permafrost zone is undergoing rapid transformation as a result of unprecedented permafrost thaw brought on by circumpolar climate warming. Rapid warming over recent decades has significantly decreased the area underlain by permafrost in peatland complexes. It has catalysed extensive landscape transitions in the Taiga Plains of northwestern Canada, transforming forest-dominated landscapes to those that are wetland dominated. However, the advanced stages of this landscape transition, and the hydrological and thermal mechanisms and feedbacks governing these environments, are unclear. This study explores the current trajectory of land cover change across a 300 000 km2 region of northwestern Canada's discontinuous permafrost zone by presenting a north–south space-for-time substitution that capitalizes on the region's 600 km latitudinal span. We combine extensive geomatics data across the Taiga Plains with ground-based hydrometeorological measurements collected in the Scotty Creek basin, Northwest Territories, Canada, which is located in the medial latitudes of the Taiga Plains and is undergoing rapid landscape change. These data are used to inform a new conceptual framework of landscape evolution that accounts for the observed patterns of permafrost thaw-induced land cover change and provides a basis for predicting future changes. Permafrost thaw-induced changes in hydrology promote partial drainage and drying of collapse scar wetlands, leading to areas of afforestation forming treed wetlands without underlying permafrost. Across the north–south latitudinal gradient spanning the Taiga Plains, relatively undisturbed forested plateau–wetland complexes dominate the region's higher latitudes, forest–wetland patchwork are most prevalent at the medial latitudes, and forested peatlands are increasingly present across lower latitudes. This trend reflects the progression of wetland transition occurring locally in the plateau–wetland complexes of the Scotty Creek basin and informs our understanding of the anticipated trajectory of change in the discontinuous permafrost zone.

Rapid Landscape Changes in Plastic Bays Along the Norwegian Coastline

The Norwegian Coastal Current transports natural debris and plastic waste along the Norwegian coastline. Deposition occurs in so-called wreck-bays and includes floating debris, such as seaweed, driftwood and volcanic pumice, and increasing amounts of plastics during the last decades. Deposition in these bays is controlled by ocean currents, tidal movements, prevailing winds and coastal morphology. We have compared soil profiles, analyzed the vegetation and inspected aerial photos back to 1950 in wreck-bays and defined three zones in the wreck-bays, where accumulation follows distinct physical processes. Zone 1 includes the foreshore deposition and consists of recent deposits that are frequently reworked by high tides and wave erosion. Thus, there is no accumulation in Zone 1. Zone 2 is situated above the high tide mark and includes storm embankments. Here, there is an archive of accumulated debris potentially deposited decades ago. Zone 3 starts above the storm embankments. The debris of Zone 3 is transported by wind from Zone 1 and Zone 2, and the zone continues onshore until the debris meets natural obstacles. Plastic accumulation seems to escalate soil formation as plastic is entangled within the organic debris Mapping and characterizing the soil layers indicates that deep soils have been formed by 50 or more years’ accumulation, while the pre-plastic soil layers are thin. The plastic soil forms dams in rivers and wetlands, changing the shape and properties of the coastal landscape, also altering the microhabitat for plants. This case-study describes an ongoing landscape and vegetation change, evidently co-occurring with the onset of plastic accumulation. Such processes are not limited to the Norwegian coastline but are likely to occur wherever there is accumulation of plastic and organic materials. If this is allowed to continue, we may witness a continued and escalating change in the shape and function of coastal landscapes and ecosystems globally.

Landscape modification due to agricultural irrigation: Carbonate tufa formation on Tenerife, Canary Islands, Spain

The use of irrigation water on Tenerife has modified the hydrogeological system resulting in the formation of an anthropogenic carbonate tufa . The processes involved in its formation are: 1) infiltration of rainwater and mixing with groundwater rich in volcanic carbon dioxide (CO 2 ), 2) weathering of volcanic rocks increasing the ion content of the water, 3) extraction of this water from subterranean galleries and channels and spilling it onto the Lomo Morin slope, 4) mechanical CO 2 degassing and photosynthetic activity driving calcite precipitation. The tufa consists of boundstones of algae and coated stems of reeds, along with laminated microbial crusts. Textures range from microspar to coarse mosaics to fibrous-radial calcite, all containing biogenic features. The presence of the green macroalga Blidingia is noticeable. Carbon stable isotope ratio ( δ 13 C) varies between -3.58 and +1.03‰ VPDB (Vienna Pee Dee Belemnite) and oxygen stable isotope ratio ( δ 18 O) between -6.77 and -5.00‰ VPDB, highlighting the largely meteoric origin of the water with some addition of deep CO 2 . A strontium isotope ratio ( 87 Sr/ 86 Sr) of 0.7030 confirms the weathering of volcanic rocks as the source of calcium. The Lomo Morin tufa provides a scale model of how water use contributes to rapid landscape change through alterations in the hydrogeological system. It also provides a good example of a CO 2 sink in a continental setting, and is comparable to the global carbon cycle, which mostly involves marine limestones. Although anthropogenic processes are commonly viewed negatively, the human modification of the hydrogeological system reported in this study has produced changes to geological and ecological conditions that have increased the geo - and biodiversity of the island.

Woodland fragments in urban landscapes are important bat areas: an example of the endangered Bechstein’s bat Myotis bechsteinii

Urban areas are increasing globally causing fragmentation and loss of habitats for many forest dwelling species. At the same time new habitats are created, which may be exploited by species with a broad ecological tolerance. Bats form the largest mammal group living in cities in Central Europe. Species diversity might be higher in some cities compared to rural areas. Yet, habitat-specialists struggle with rapid landscape change and urban development. The Bechstein’s bat Myotis bechsteinii is dependent on old growth deciduous forests that supply tree cavities to roost in. The use of small home ranges requires high prey abundance around roosts. Despite their habitat specialization we identified two Bechstein’s maternity colonies within the metropolitan area of Frankfurt/Main (Germany). The colonies numbered 25 and 31 adult females respectively. We radio tracked individuals from both colonies (n = 14) and compared their habitat use to that of females (n = 79) of 11 colonies from rural woodlands. We identified a total of 29 roosts used by the two maternity colonies during summer. Roost choice of the urban forest colonies was similar to the rural forest colonies with a preference for oak trees with woodpecker holes. The distances between roosts were similar between urban and rural colonies. Habitat selection was strongly towards old forest patches. We emphasize the importance of the persistence of old forest islands within urban areas to support remaining bat colonies with a network of bat areas, similar to the important bird areas (IBAs). Specialized species that fail to adapt to the rapid changes may survive within the urban environment relying on old forest patches.

Preface

FOREWORD The 4th International Symposium for Sustainable Landscape Development (The 4th ISSLD) was a continuation from the 3rd ISSLD which was held in 2017. The symposium was aimed to explore new ideas and discuss interdisciplinary science for Sustainable Landscape Development. In this modern era, landscape development must consider the multidisciplinary approach in facing the rapid landscape changes that have a remarkable impact on human. Disaster, food security, sustainable practices and the advance technologies are among other challenges that need to be taken into account.The main background of this symposium concerns the disaster that getting frequent occurred in Indonesia and around the globe. The nature link-disaster such as tsunami, earthquake and volcanic eruption; the climate-linked disasters which to a great extent related to climate change phenomena; and human-link disasters such as forest fire and land-use changes have threatened the environment and humanity. Therefore, every community must be prepared to be able to anticipate those disasters which can be achieved through landscape preservation, conservation and restoration intertwined with landscape development. The second concern that underlying the symposium is the rise of the fourth industrial revolution that closely related to digital technology. We believe that technology plays a significant role in the processes of landscape research and development, particularly related to disasters and food security.Based on those considerations, therefore, in this symposium, we invited researchers, government officials, academicians and professionals to exchange ideas related to four issues:1. Post Disaster Management, Restoration, Mitigation and Resilience in Landscape2. Landscape Planning and Management for Supporting Food Security in Vulnerable Landscape3. Future Issue and Disruptive Technology of 4.0 in Landscape Architecture4. Sustainable Landscape Architecture: Design, Planning and ManagementThe 4th ISSLD was held on October 10th, 2019 at the IPB International Convention Centre (IICC), Bogor, Indonesia. This event was organized by the Department of Landscape Architecture, Faculty of Agriculture, IPB University. The participants came from various affiliations and countries including Croatia, Japan, Philippine, Malaysia and Indonesia. In this symposium, student participants were encouraged to participate in paper and poster presentation that becoming student competition. The symposium produced 49 papers which are peer-reviewed and published in this issue of IOP Conference Series: Earth and Environmental Science (EES).We would like to thank all authors who have shared knowledge and ideas through the articles that have composed the proceeding of the 4th ISSLD. Our credits go to the reviewers who have committed to evaluate the papers on time. We would also like to thank the organizing committee, steering committee, keynote and invited speakers, participants and students who have made this event a success. We wish to thank IOP Publishing for making this publication possible. Last but not least we gratefully acknowledge the financial support from the sponsors: IPB University, Food Security Agency - Ministry of Agriculture Republic, and Bank Negara Indonesia.Hopefully this proceeding could bring a new perspective in landscape science and development to reach sustainability.Akhmad Arifin HadiEditor-in-ChiefEditorial Committees, Scientific Committees, Editor Assistant and Conference photographs are available in the pdf.

Virginia opossum distributions are influenced by human-modified landscapes and water availability in tallgrass prairies

AbstractThe Flint Hills represent the largest tract of tallgrass prairie in North America and is located near the western edge of the native range of the Virginia opossum (Didelphis virginiana). This region is undergoing rapid landscape changes (e.g., urbanization, agriculture, woody encroachment) that are negatively affecting mammal communities. Although previous research has revealed northward distributional expansions of Virginia opossums facilitated by urban development, no studies have assessed how landscape change affects distribution patterns along the western edge of their geographic range. During 2016–2018, we monitored site (n = 74) occupancy along urban–rural transects in the Flint Hills to assess the influence of landscape change (i.e., urban, grassland, agriculture, woody encroachment) and water availability on the distribution of Virginia opossums. Sites surrounded by urban land cover had greater initial occupancy probabilities and lower extinction rates. Sites closer to permanent water sources experienced greater colonization rates and lower extinction rates. In addition, site extinction rates were lower in areas surrounded by woody encroachment. Our results concur with other studies suggesting that growing urban areas may expand opossum distributions along the edges of their geographic range. Our study also suggests that woody encroachment into tallgrass prairies may provide an alternative pathway for future distributional expansions. Future research must consider the potential for landscape change, along with dynamic water availability, in models predicting the distribution of Virginia opossums.

Impact of Land Use Land Cover (LULC) Change on Surface Runoff in an Increasingly Urbanized Tropical Watershed

Upper-Brantas watershed in East Java, Indonesia, is a tropical watershed experiencing rapid landscape change, a phenomenon typical to developing countries. This study demonstrates the impact of Land Use Land Cover (LULC) changes on surface runoff in a tropical, urbanized, and data scarce watershed. The LULC changes were quantified between 1995 and 2015 and their impact on the hydrological processes was analyzed using the Soil and Water Assessment Tool (SWAT) model. During the study period, the watershed experienced an increase in settlement and dryland agriculture, and a decrease in the forest, rice field, and sugarcane plantation. The SWAT model results for the calibration (2003–2008) and validation (2009–2013) periods matched observed values [R2 > 0.91 and NSE (Nash-Sutcliffe Efficiency) >0.91]. In the long-term, the model predicted changes in runoff (+8%), water yield (+0.28%), groundwater (−1.8%), and evapotranspiration (−1.15%) due to changes in LULC. LULC changes showed a linear relationship with runoff generation, and the most significant factors affecting surface runoff were changes in the forest, agriculture, and settlements. Increasing urbanization, industrialization, and agricultural intensification will increase runoff which in turn will enhance the flow of nutrients and sediments into the water bodies.

Livelihoods, Wellbeing and the Risk to Life During Volcanic Eruptions

A forensic analysis of fatalities and displacements from recent volcanic eruptions (1986-2015) provides insights into factors that influence actions to protect life in high-risk environments. Unlike many other geophysical hazard events, volcanic eruptions may be prolonged, and of variable intensity. This is reflected in patterns of volcanic fatalities. A global survey reveals that 63% of primary volcanic deaths occur after the first week of activity, with >44% of these deaths associated with citizens returning to an established high-hazard zone. Evacuations during volcanic eruptions are protracted and this allows time for competing pressures to arise. Examination of detailed data from three volcanic crises (Soufriere St. Vincent, Soufriere Hills, Montserrat and Tungurahua, Ecuador) suggests that the need to preserve livelihoods plays a strong role in protecting life. A dynamic, associated with pull (e.g. protecting assets, place attachment) and push factors (e.g. poor shelter conditions), can draw evacuees to return during high-risk periods. Similar considerations can restrain people with previous experience of volcanic hazards and displacement, from evacuating. Our global analysis shows that these pressures, when coupled with forecasting uncertainties and the rapid landscape change associated with volcanic eruptions, mean that the physical and social vulnerability of populations change significantly during the course of an eruption. Ongoing risk to life is shaped by hazard experience and action; timescales of hazard escalation and their relationship to warning and action; and the timescales over which evacuation conditions are tolerable to livelihood and asset preservation, and mental and physical wellbeing in shelters.

Predicting hydrologic disturbance of streams using species occurrence data

Aquatic organisms have adapted over evolutionary time-scales to hydrologic variability represented by the natural flow regime of rivers and streams in their unimpaired state. Rapid landscape change coupled with growing human demand for water have altered natural flow regimes of many rivers and streams on a global scale. Climate non-stationarity is expected to further intensify hydrologic variability, placing increased pressure on aquatic communities. Using a machine learning approach and georeferenced species occurrence data, we modeled and mapped spatial patterns of hydrologic disturbance for streams in Arkansas, Missouri, and eastern Oklahoma. Random forest (RF) models trained on fish community data, hydrologic, and landscape metrics for gaged streams in the National Hydrography (NHDPlusV2) database were used to predict a hydrologic disturbance index (HDI) for ungaged streams. The HDI is part of the USGS Geospatial Attributes of Gages for Evaluating Streamflow (GAGESII) database and is a composite index of watershed-scale disturbance from anthropogenic stressors. Fish presence/absence data had similar overall model prediction accuracy (77%; 95% CI: 0.74, 0.80) as flow variables (76%; CI: 0.73, 0.80). Including topographic variables increased the RF prediction accuracy of both the fish (90%; CI: 0.88, 0.92) and flow models (86%; CI: 0.84, 0.89). Spatial patterns of hydrologic disturbance suggest distinct ecohydrological regions exist where conservation actions may be focused. Streams with low HDI were predominately located in the Ozark Highlands, Boston Mountains, and Ouachita Mountains. Correlation analysis of HDI by flow regime showed groundwater stable streams had the lowest disturbance frequency, with over 50% of stream reaches with low HDI located in forested land cover. HDI was highest for big rivers, intermittent runoff streams and streams in areas of agricultural land use. Our results show long-term georeferenced biological data can provide a valuable resource for predictive modeling of hydrologic disturbance for ungaged rivers and streams.

Pliocene erosional pulse and glacier-landscape feedbacks in the western Alaska Range

Pliocene–Pleistocene glaciation modified the topography and erosion of most middle- and high-latitude mountain belts, because the evolution of catchment topography controls long-term glacier mass balance and erosion. Hence, characterizing how erosion rates change during repeated glaciations can help test hypothesized glacier erosion-landscape feedbacks across a range of settings. To better understand how glaciations and landscapes coevolve on geologic timescales, I quantify erosion rates in the glaciated western Alaska Range with low-temperature thermochronometric data and modeling. Zircon (U–Th)/He and apatite fission track data suggest mountain-building was underway by the early Miocene. In contrast, lower-temperature apatite (U–Th)/He age-elevation and grain age-kinetic data indicate that erosion accelerated coincident with regional Pliocene glaciation ca. 4 Ma. Furthermore, erosion rates calculated within an eroding half-space indicate slow erosion at a rate ≤0.3 km/m.y. before 4.2 Ma, an initial pulse of rapid erosion at a rate of 1.0–1.6 km/m.y. during 4.2–2.9 Ma, and more moderate erosion at a rate of 0.4–0.7 km/m.y. since 2.9 Ma. The initial erosion pulse suggests a significant transient landscape adjustment to the introduction of efficient glacial erosion. The subsequent decrease in Pleistocene erosion rates is consistent with a negative feedback between continuing glaciation and glacier size/erosivity: If glacial erosion outpaces rock uplift, glacier erosion decreases over time as topography, mass balance, valley gradients, and ice flux are reduced. These findings imply that in areas of moderate rock uplift rates, the onset of local Plio–Pleistocene glaciation may have been punctuated by an initial pulse of rapid landscape change, after which change became more gradual.

Conservation genetics of eastern Australian herpetofauna in a rapidly changing landscape: a perspective on conservation management and policy implementation

Over the last 200 years Australia has seen wide-scale habitat losses and land-clearing but in the last two decades the rate of loss has been accelerating dramatically, with intensification of land clearing and unprecedented urban growth around most of our major cities. It is within this framework of such rapid change that I have been undertaking conservation genetic research of lizards and frogs over the last 15 years. Here I reflect on the impacts of two rapidly changing landscapes that I have documented through my research. First, the profound impact of land clearing and shifting agricultural practices from mixed-cropping farms to vast broadacre monocultures on the grassland earless dragons of the Condamine River floodplains in south-eastern Queensland. Second, the rapid expansion of the Melbourne urban growth boundaries and how planning processes can impact the future survival of lizard and frog species within an urban environment. Both these cases highlight the impacts of rapid landscape change and emphasise the need for appropriate regulation and planning. Recommendations to slow the detrimental decline and potential extinction of these species include tighter land-clearing regulations and compliance monitoring, plus funding and integration of high-quality research into planning policy at early strategic stages. However, it is also vital that as conservation researchers we effectively communicate to the wider community our knowledge of the impacts that these landscape changes are having on our native flora and fauna.

DESLIZAMENTOS E FRAGMENTAÇÃO FLORESTAL NA REGIÃO SERRANA DO ESTADO DO RIO DE JANEIRO

A fragmentação florestal é um processo em que áreas contínuas de vegetação natural são subdivididas em manchas de tamanhos diversos, originado por atividades antrópicas ou causas naturais associadas às mudanças ambientais e eventos de grande magnitude. O presente trabalho tem por objetivo caracterizar e analisar a dinâmica da fragmentação florestal e a vulnerabilidade das manchas de distúrbios resultantes de deslizamentos ocasionados por chuvas intensas na região serrana do estado do Rio de Janeiro em 2011. Para tanto foi realizada uma avaliação do padrão espacial das manchas antes e após os eventos por meio de índices métricos de paisagem, estimados a partir de mapas de cobertura da terra e das cicatrizes dos deslizamentos, produzidos através da análise de imagens orbitais. Houve uma redução de 6% da área de floresta e um acréscimo de 107% no número de fragmentos, principalmente de pequenos. Ocorreu uma perda de 17% da área nuclear, um acréscimo de 43% do número de núcleos e de 28% da densidade de borda. A distância média do fragmento mais próximo diminuiu 46%, em virtude da forma das cicatrizes, alongadas e estreitas. Os resultados mostram que os deslizamentos ocasionaram uma intensificação do processo histórico de fragmentação florestal, promovendo um aumento da vulnerabilidade e instabilidade ecológica dos remanescentes florestais, evidenciando como eventos naturais de grande magnitude podem alterar rapidamente a paisagem.