Landscape Modification Research Articles

Physicochemical Characterisation of Water and Sediment of the Semimechanized Artisanal Gold Mining Environment of the Béké Locality

This paper aims to investigate the level of pollution of water, sediment, and soil due to semimechanized artisanal gold mining in Béké, Adamawa region of Cameroon. For this purpose, water and sediment samples were collected and analyzed. In order to achieve this goal, several research studies and field observations were carried out. Questionnaires were also used to complement field investigations. All these enabled the identification of the potential sources of impacts on the human, physical, and biological environment. Three soil samples (S1, S5, and S7) were collected on the same spot with the water sample and analyzed to assess the intensity of soil contamination. The water samples (W1–S9) were characterized physically, chemically, and microbiologically to evaluate the water quality contamination. The results of the physicochemical analysis of the water samples showed that the rivers in this zone are moderately acidic (with pH values ranging from 5.11 to 6.37) and slightly mineralized (with sample W2 collected from the Béké river having an iron concentration of 6.7 g/L). The pattern of mean trace metal concentration in sediments was Fe > Mn > Cr > Pb > Cu > Zn. According to pollution indices, the contamination degree (CD) varied from 4.03 to 4.56 corresponding to low contamination. The index of ecological risk (Eri) for all the trace metals was low (Eri ≤ 40) and the geoaccumulation index (Igeo) ranged between uncontaminated and moderately contaminated (Igeo 0-1). The result of our field investigations and analysis shows that the semimechanized artisanal gold mining in the locality of Béké has very significant environmental consequences such as land degradation, deforestation, water pollution, and landscape modification.

Lithological controls of the Mg isotope composition of the Lena River across seasons and its impact on the annual isotope flux to the Arctic Ocean

Given the importance of permafrost regions in providing the major elements to the Arctic Ocean, and the vulnerability of these regions to ongoing climate change due to permafrost thaw and landscape modifications, assessing the magnitude and characterizing the factors governing isotope compositions in river waters across seasons and space is of high priority.Towards identifying possible environmental controlling factors (climate, vegetation, rock lithology) and quantifying annual fluxes of dissolved Mg isotopic signatures in large Arctic rivers located in the continuous permafrost zone, here we measured hydrochemical and Mg isotope compositions of the Lena River main channel and its various tributaries over different seasons of the year. In general, we did not find evidence of any statistically significant (p < 0.05) correlation between δ26Mg and main physico-geographical parameters of the river watersheds (temperature, permafrost, type of vegetation). The exception is the decrease in riverine δ26Mg values that was accompanied by an increase in the carbonate rock proportion in the watershed, whereas an opposite trend was observed for the abundance of terrigenous and silicate rocks. An incontestable control of dolomite rocks on Mg isotope signature in the Lena River was also supported by decreasing δ26Mg values with increasing Dissolved Inorganic Carbon (DIC) concentration, as also observed for other Artic River basins. This relationship was mostly pronounced during the high-flow period, when secondary Mg silicate formation in soils and underground waters and so the terrestrial uptake of Mg were the lowest. In the Lena River main channel, the lowest δ26Mg values (−1.5 ± 0.05 ‰) were observed during autumn-winter (September to March), probably reflecting a dominant role of underground reservoirs and subsurface soil weathering of isotopically light Precambrian dolomites.The mean δ26Mg values of the Lena River during two months of spring (−1.02 to −1.28 ‰), 4 months of summer baseflow (−1.30 ‰) and 6 months of winter yields a mean discharge-weighted annual value of −1.26 ± 0.05 ‰. This number coincides with the value of summer baseflow reported in earlier works. Therefore, like in the recently studied Yenisey River basin, the Mg isotope signature of the Lena River water likely stems from a mixture of carbonate (−2.0 ≥ δ26Mg ≥ −2.5 ‰) and silicate (0 ≥ δ26Mg ≥ −0.2 ‰) rocks in its watershed. We also argue that the discharge-weighted mean annual isotopic signature of an element in the Artic rivers can be reasonably approximated by a single sampling campaign during summer baseflow. This allows cost-effective assessment of mean riverine isotopic signatures of other elements in both small and large rivers to the Arctic Ocean.

The impact of laser lift-off with sub-ps pulses on the electrical and optical properties of InGaN/GaN light-emitting diodes

Laser lift-off (LLO) is an important step in the processing chain of nitride-based light-emitting diodes (LEDs), as it enables the transfer of LEDs from the growth substrate to a more suitable carrier. A distinctive feature of LLO with ultrashort pulses is the ability to use either above- or below-bandgap radiation, since nonlinear absorption becomes relevant for ultrashort pulses. This study addresses the differences in the absorption scheme for below- and above-bandgap radiation and investigates the electrical and optical properties of InGaN/GaN LEDs before and after LLO with 347 and 520 nm laser light via current–voltage and power- as well as temperature-dependent photoluminescence measurements. LLO could be successfully realized with both wavelengths. The threshold fluence required for LLO is about a factor of two larger for 520 nm compared to that for 347 nm. Furthermore, an increase in leakage current by several orders of magnitude and a significant decrease in efficiency with laser fluence are observed for below-bandgap radiation. In contrast, leakage current hardly increases and efficiency is less dependent on the laser fluence for samples lifted with 347 nm. This degradation is ascribed to the absorption of laser light in the active region, which facilitates a modification of the local defect landscape. The effect is more severe for below-bandgap radiation, as more laser light penetrates deep into the structure and reaches the active region. Ultimately, we show that LEDs lifted with ultrashort laser pulses can exhibit good quality, making ultrashort pulse LLO a viable alternative to conventional LLO with nanosecond pulses.

Underlying and proximate drivers of biodiversity changes in Mesoamerican biosphere reserves

Protected areas are of paramount relevance to conserving wildlife and ecosystem contributions to people. Yet, their conservation success is increasingly threatened by human activities including habitat loss, climate change, pollution, and species overexploitation. Thus, understanding the underlying and proximate drivers of anthropogenic threats is urgently needed to improve protected areas' effectiveness, especially in the biodiversity-rich tropics. We addressed this issue by analyzing expert-provided data on long-term biodiversity change (last three decades) over 14 biosphere reserves from the Mesoamerican Biodiversity Hotspot. Using multivariate analyses and structural equation modeling, we tested the influence of major socioeconomic drivers (demographic, economic, and political factors), spatial indicators of human activities (agriculture expansion and road extension), and forest landscape modifications (forest loss and isolation) as drivers of biodiversity change. We uncovered a significant proliferation of disturbance-tolerant guilds and the loss or decline of disturbance-sensitive guilds within reserves causing a "winner and loser" species replacement over time. Guild change was directly related to forest spatial changes promoted by the expansion of agriculture and roads within reserves. High human population density and low nonfarming occupation were identified as the main underlying drivers of biodiversity change. Our findings suggest that to mitigate anthropogenic threats to biodiversity within biosphere reserves, fostering human population well-being via sustainable, nonfarming livelihood opportunities around reserves is imperative.

Africa and the Cattle Without History.

The premise of this article is that African historiography has yet to embrace the genetic basis of cattle tolerance to tsetse-borne trypanosomiasis due to the literature's emphasis on human illness and landscape modification. By the early 1980s, empirical research indicated that N'Dama cattle possessed a tolerance to the disease that was heritable and, as such, could be strengthened through breeding. The Gambia's first president, who was a former veterinary surgeon, contributed to the breed's reappraisal. In exploring this history, I show how an international scientific network positioned The Gambia as a supplier of N'Dama breeding stock for livestock developments in sub-Saharan Africa. My argument is that research on cattle genetics has theoretical consequences for writing about the history of African tsetse ecosystems.

Assessment of anthropogenic-causing-agents act on waterbirds-diversity in the vicinity of Tarbela Dam, Indus River, Pakistan.

Birds are among the best bio-indicators, which can guide us to recognize some of the main conservation concerns in ecosystems. Anthropogenic impacts such as deforestation, habitat degradation, modification of landscapes, and decreased quality of habitats are major threats to bird diversity. The present study was designed to detect anthropogenic causative agents that act on waterbird diversity in Tarbella Dam, Indus River, Pakistan. Waterbird censuses were carried out from March 2019 to February 2020 in multiple areas around the dam. A total of 2990 waterbirds representing 63 species were recorded. We detected the highest waterbird richness and diversity at Pehure whereas the highest density was recorded at Kabbal. Human activity impacts seemed to be the main factor determining the waterbird communities as waterbirds were negatively correlated with the greatest anthropogenic impacts. Waterbirds seem to respond rapidly to human disturbance.

Adrenal and metabolic hormones demonstrate risk-reward trade-offs for African elephants foraging in human-dominated landscapes.

A key driver of the African savannah elephant population decline is the loss of habitat and associated human-elephant conflict. Elephant physiological responses to these pressures, however, are largely unknown. To address this knowledge gap, we evaluated faecal glucocorticoid metabolite (fGCM) concentrations as an indicator of adrenal activity and faecal thyroid metabolite (fT3) concentrations as an indicator of metabolic activity in relation to land use, livestock density, and human landscape modification, while controlling for the effects of seasonality and primary productivity (measured using the normalized difference vegetation index). Our best-fit model found that fGCM concentrations to be elevated during the dry season, in areas with higher human modification index values, and those with more agropastoral activities and livestock. There was also a negative relationship between primary productivity and fGCM concentrations. We found fT3 concentrations to be higher during the wet season, in agropastoral landscapes, in locations with higher human activity, and in areas with no livestock. This study highlights how elephants balance nutritional rewards and risks in foraging decisions when using human-dominated landscapes, results that can serve to better interpret elephant behaviour at the human-wildlife interface and contribute to more insightful conservation strategies.

Characteristic analysis of village cultural landscape by Lian Li space information technology and three-dimensional modelling

Abstract At present, due to the traditional village landscape protection method being relatively single, resulting in the traditional village landscape tends to “homogenization,” which is not conducive to the development of the village cultural landscape. This paper combines spatial information technology and three-dimensional modeling to reconstruct the village landscape and analyze its characteristics. Low-altitude oblique photography technology is used to collect village landscape information from multiple angles and then combined with the 3D model imaging law covariance equations to form the landscape 3D model features and then complete the multi-visual 3D model information matching. Finally, through texture mapping, the 3D model is generated to match the color of the real landscape. Using BIM technology, the data is refined to address the problem of local defects in the landscape 3D reconstruction process. The proposed technology is applied in practice to analyze the spatial comprehensibility of the test village landscape, and the comprehensibility value R² is obtained as 0.317, which is a poor spatial order of the test village. The village residents’ actual landscape color perception of the town ranges from -0.0364 to 0.4566, and the expected range is above 0.7. The actual perception is much lower than the predicted perception, and the subsequent landscape modification should be close to the villagers’ expectations.

Landscape modification induced by forest plantations in a section of the Maulino coastal forest, Chile

In this work were quantified and assessed the recent changes in the landscape composition and configuration of the Maulino Coastal Forest, located in central Chile, strongly affected by the forest plantations expansion. To achieve that, a set of landscape metrics were applied on its main vegetation land covers; derived from the official vegetation and land use cadasters of 2009 and 2016. Within the relatively short study period addressed, it was possible to confirm important changes in the landscape of the study area, mainly driven by an increase in the area covered by forest in the form of relatively small, compact, and irregularly shaped patches, which influenced the constriction, disconnection, and distancing of those patches of native vegetation. These results widely agree with those referred by previous studies, thus confirming the permanence of the fragmenting process that have affected this type of forest and consequently, the urgency of implementing actions aimed to its management and conservation.

Whakamana te tangata – ka whai oranga te taiao: Indigenous led approaches for catchment health in Aotearoa-New Zealand

Large-scale transformation and modification of landscapes have occurred across most catchments in Aotearoa-New Zealand (A-NZ) in the past 200-years (mainly mid-1800s to mid- 1900s). This has been mainly through large-scale removal of indigenous forest and draining of wetlands to a landscape dominated by urban settlement and highly modified landscapes. The expansive shift to pastoral farming and urban settlement, under a colonial settlement vision has increasingly led to detrimental cumulative impacts on ecological health. Environmental decline has been tightly linked to significant adverse impacts on Māori (the Indigenous people of A-NZ) wellbeing. For Māori, this has been out of balance and step with an indigenous-based vision of A-NZ. To understand how a Māori worldview can help drive transformation in the health of our catchments and their communities, we argue that an Ao Māori (Māori worldview) framing for catchment management is necessary with reference to three catchment case studies (Kaipara, Waikato, and Waiapu). These case studies were chosen because they provide tangible examples of resurgence in the use and understanding of mātauranga Māori (Māori knowledge) next to co-governance, co-management, and decision-making. In the Kaipara, the collaborative governance model ensured that all parties’ views were understood and factored into decision making and this has led to growing social equity and more sustainable relationships with the whenua. Similarly, in the Waikato, co-governance of the waterways has increased the efficiency and effectiveness of the process. Knowledge sharing and engagement has directly driven positive environmental outcomes. So too for the Waiapu, where increased hapū/iwi capability and capacity has increased social cohesion and implementation of targeted actions to mitigate climate change impacts. We explore how by adopting a holistic approach to environmental stewardship, and having intimate knowledge at place, Māori thinking has the potential to rejuvenate environmental management, emphasising the necessity of partnership-based approaches.

Enhancing Understanding of Hydrologic Processes in the Shafe Watershed, Ethiopia

Research on the combined impact of watershed attributes on streamflow is crucial in water resources planning and management, particularly due to the strong link between landscape modification and watershed attributes. However, identifying critical watershed attributes remains a challenge. This study focuses on investigating the impact of watershed attributes on streamflow in the Hare catchment of Ethiopia’s rift valley lakes basin. The Soil and Water Assessment Tool (SWAT) rainfall–runoff model was used, calibrated, and validated against observed discharge data to identify remedial measures for streamflow generation. The model’s performance was evaluated using criteria such as R2, NSE, PBIAS, and RSR, which yielded satisfactory values. The study found significant changes in land cover, with forest and shrub land declining and agricultural land expanding. Comparing mean annual streamflow between 1998, 2009, and 2021, streamflow at 2021 land use and land cover increased by 13.03% compared to 2009, which had already increased by 16.05% compared to 1998. The study also examined the impact of climate variations by manipulating meteorological data length and average slope. Overall, this study provides valuable insights into the relationship between watershed attributes and streamflow, emphasizing the importance of considering land cover changes and climate variations for effective water resource management in the Hare catchment.

Seasonal dynamics in the mammalian microbiome between disparate environments.

Host-associated bacterial microbiomes can facilitate host acclimation to seasonal environmental change and are hypothesized to help hosts cope with recent anthropogenic environmental perturbations (e.g., landscape modification). However, it is unclear how recurrent and recent forms of environmental change interact to shape variation in the microbiome. The majority of wildlife microbiome research occurs within a single seasonal context. Meanwhile, the few studies of seasonal variation in the microbiome often restrict focus to a single environmental context. By sampling urban and exurban eastern grey squirrel populations in the spring, summer, autumn, and winter, we explored whether seasonal rhythms in the grey squirrel gut microbiome differed across environments using a 16S amplicon sequencing approach. Differences in the microbiome between urban and exurban squirrels persisted across most of the year, which we hypothesize is linked to anthropogenic food consumption, but we also observed similarities in the urban and exurban grey squirrel microbiome during the autumn, which we attribute to engrained seed caching instincts in preparation for the winter. Host behaviour and diet selection may therefore be capable of maintaining similarities in microbiome structure between disparate environments. However, the depletion of an obligate host mucin glycan specialist (Akkermansia) during the winter in both urban and exurban squirrels was among the strongest differential abundance patterns we observed. In summary, urban grey squirrels showed different seasonal patterns in their microbiome than squirrels from exurban forests; however, in some instances, host behaviour and physiological responses might be capable of maintaining similar microbiome responses across seasons.

APOE‐targeted epigenome therapy for late onset Alzheimer’s disease

AbstractBackgroundCarrying the APOEe4 variant significantly increases lifetime risk for LOAD. The accumulating evidence suggest that alteration of the expression of APOEe4 and APOE may hold promise as a potential therapeutics target for LOAD. In this study we developed an epigenome therapy platform to reduce APOE and APOEe4 specifically by targeted modification of the epigenome landscape within APOE locus.MethodOur approach is based on CRISPR/dCas9‐editing strategy. The novel system based on the novel bipartite repressor platform, recently developed in the laboratory. We designed targeting of APOEe4 in the allele‐discriminatory fashion, as such the editing is allele specific and precise. Furthermore, we developed a similar approach to target the regulatory elements within APOE promoter. We evaluated our platform in vitro using human hiPSC‐derived neurons and organoids, as well as in vivo by stereotactic injection of the developed system into the hippocampus of the ApoE‐humanized mice, harboring human ApoE loci replaced the mouse ortholog.ResultUsing the system, we demonstrated an efficient and precise editing of APOeE4 and APOE expressions in the hiPSC‐derived neurons and the human isogenic APOEe4 organoids. We showed that the system can robustly reduce the levels of APOE‐mRNA and the protein in both models. Importantly, the allele‐discrimination approach has resulted in no detectable editing of the e3 allele in the isogeneic hiPSC‐derived neurons, and organoids homozygous for the e3 allele. Moving onto in vivo studies, the promoter‐targeted approach using adeno‐associated‐ dCas9‐KRAB‐MeCP2 vector injected into the hippocampus of APOEe4 and APOEe3 mice, showed 50‐70% decrease in the mRNA and the protein levels. Similar effect was observed using lentivirus‐ CRISPR/Cas system targeted ApoEe4 in allele‐specific manner. Collectively, our results provided in vitro and in vivo proof‐of‐concept for the utility and efficacy of the APOE‐targeted epigenome therapy.ConclusionOur epigenome therapy strategy for fine‐tuning of APOE expression based on dCas9 technology is translational toward the development of a therapeutics approach to prevent and/or delay LOAD onset. Furthermore, the technology offers the opportunity to refine the platform for the development of gene‐specific and even allele‐ and cell‐type‐ specific therapies, and by that enables the advancement of strategies for precision medicine in LOAD.

Assessing effects of landscape modifications and identifying priority areas for two Asian otters in coastal wetlands

Conserving species inhabiting areas overlapped with human settlements is more challenging than usual as anthropogenic impacts need to be accounted for when management plans are formulated. This study aims to identify conservation priority areas for two otter species and evaluate the impact of land-use changes on conservation management in the coastal wetlands of southern Thailand. We conducted camera-trap surveys across 283 grids of 25 km2 each between 2016 and 2020. A single-species occupancy model was applied to estimate the occupancy probability of two otter species in relation to landscape characteristics and human factors. Occupancy probabilities were then correlated with anthropogenic threat levels obtained from Bayesian Belief Network to identify conservation management hotspots and conservation importance areas under various scenarios. The Smooth-coated Otter shows a higher occupancy probability in the Andaman, where a larger proportion of less disturbed wetlands remains compared to the Gulf. The Small-clawed Otter, in contrast, has higher occupancy in the Gulf. In the Andaman, the Smooth-coated Otter appears to occupy areas associated with lower human impacts and a higher proportion of natural habitats, while in the Gulf, both otter species have higher occupancy in areas where modifications of natural habitats are more intensive. In total, 1350 km2 were identified as very high conservation management hotspots, with an additional 750 km2 identified as very high conservation importance. The majority of these areas were located along the Andaman coast. However, land-use changes expanded the management hotspot areas to 2025 km2 while reducing conservation importance areas to just 175 km2. Our results emphasize the importance of protecting natural habitats and the urgency of implementing management interventions for otters on the Andaman coast, for the long-term survival of these threatened species.

HESS Opinions: Drought impacts as failed prospects

Abstract. Human actions induce and modify droughts. However, scientific gaps remain with respect to how hydrological processes, anthropogenic dynamics, and individuals' perceptions of impacts are intrinsically entangled in drought occurrence and evolution. This adds complexity to drought assessment studies that cannot be addressed by the natural and environmental sciences alone. Furthermore, it poses a challenge with respect to developing ways to evaluate human behaviour and its pattern of co-evolution with the hydrological cycle – mainly related to water use and landscape modifications. During fieldwork in Brazil, we observed how drought impacts were experienced by people who were exposed to a multi-year drought. Evaluating our data, it appeared that prospect theory, a behavioural economic theory that is usually applied to explain decision-making processes under uncertainty, has explanatory power regarding what we observed in the field. Therefore, we propose an interdisciplinary approach to improve the understanding of drought impact emergence using this theory. When employing prospect theory in this context, drought impacts are considered failed welfare expectations (“prospects”) due to water shortage. A shifting baseline after prolonged exposure to drought can therefore mitigate experienced drought impacts. We demonstrate that this theory can also contribute to explaining socio-hydrological phenomena, such as reservoir effects. This new approach can help bridge natural science and social science perspectives, resulting in integrated drought management that considers the local context.

Interests, beliefs, experience and perceptions shape tolerance towards impacts of recovering predators

Abstract The modification of landscapes is increasing the interface between humans and wildlife, while conflicts concerning predator impacts on human activities persist. Some previously persecuted but now protected predator species are experiencing recovery and range expansion. Tolerance is considered essential for achieving coexistence between humans and wildlife; however, its conceptualisation remains unresolved. Little is known about tolerance in the context of recovering predators, particularly which drivers are relevant to all or specific species and human interests. Using an online questionnaire survey shared with members of organisations with interests in rural land‐based activities, we collected data on interests and beliefs, and attitudes, perceptions, experience and management preferences for six recovering vertebrate predators in the United Kingdom (n = 819). We created a species tolerance score representing the management choices of the respondents in different conflict scenarios, which differed in the degree of impact on the predator population. Our species tolerance score was characterised by a complex combination of the interests and beliefs of the respondents about wildlife management, perceptions and experience of that species (perceived benefits, population trend, positive and negative experience, indirect negative experience) and negative experience of other recovering predators. We found a tolerance gradient between interest groups with notable overlap between groups with primary interests in wildlife conservation, shooting, farming and fishing. Although higher perceived benefits consistently corresponded to higher tolerance, having a negative experience of the species dampened the effect of perceived benefits on tolerance. When both negative personal and indirect experiences were reported, tolerance was dramatically reduced. The classification of species from least to most tolerated was consistent between interest groups. The application of our species tolerance score as the normative dimension (i.e. acceptability) in Brenner and Metcalf's (2020) Social Tolerance of Wildlife Framework highlights that tolerance (negative attitude—high acceptability) is potentially rare and more positive attitudes must be achieved before acceptance of the impacts of species can increase. Our findings highlight that considering only primary interests may hinder debates concerning recovering predators. Strategies to reduce negative experiences or change how they are perceived could significantly increase tolerance in combination with increasing positive experiences. Read the free Plain Language Summary for this article on the Journal blog.

Ecosystem productivity drives the breeding success of an endangered top avian scavenger in a changing grazing pressure context

Environmental conditions and resource availability shape population dynamics through direct and indirect effects of climate, biological interactions and the human modification of landscape. Even when a species seems dependent on predictable anthropogenic food resources or subsidies, ecosystem-level factors can still determine population dynamics across taxa. However, there is still a knowledge gap about the cascade effects driven by climate, vegetation functioning, resource availability and governmental policies on key aspects of species reproduction for top scavengers. Here we put to good use 22 years (2000−2021) of extensive population monitoring from the endemic Canary Egyptian vulture (Neophron percnopterus majorensis) on the Fuerteventura Island (Canary Islands, Spain) to study the relative importance of demographic factors, ecosystem conditions and availability of anthropogenic food sources on breeding success. Our results suggest that ecosystem-level primary productivity, the number of livestock animals present on the island and Density-dependent processes determine the temporal changes in the breeding success of this species. We firstly accounted for a top-down effect of livestock on island vegetation, where overgrazing directly reduces landscape-level vegetation biomass. We, consequently, found a bottom-up effect between vegetation and the Egyptian vulture's breeding success. In this context, minimal changes in ecological conditions can impact the species inhabiting these ecosystems, with direct consequences on a key population stage, such as breeding season, when energy requirements are higher. These results are especially relevant because cascading and indirect effects of ecosystem processes and governmental policies are often overlooked when pursuing conservation goals of endangered species.

Bayesian regression versus machine learning for rapid age estimation of archaeological features identified with lidar at Angkor

Lidar (light-detection and ranging) has revolutionized archaeology. We are now able to produce high-resolution maps of archaeological surface features over vast areas, allowing us to see ancient land-use and anthropogenic landscape modification at previously un-imagined scales. In the tropics, this has enabled documentation of previously archaeologically unrecorded cities in various tropical regions, igniting scientific and popular interest in ancient tropical urbanism. An emerging challenge, however, is to add temporal depth to this torrent of new spatial data because traditional archaeological investigations are time consuming and inherently destructive. So far, we are aware of only one attempt to apply statistics and machine learning to remotely-sensed data in order to add time-depth to spatial data. Using temples at the well-known massive urban complex of Angkor in Cambodia as a case study, a predictive model was developed combining standard regression with novel machine learning methods to estimate temple foundation dates for undated Angkorian temples identified with remote sensing, including lidar. The model’s predictions were used to produce an historical population curve for Angkor and study urban expansion at this important ancient tropical urban centre. The approach, however, has certain limitations. Importantly, its handling of uncertainties leaves room for improvement, and like many machine learning approaches it is opaque regarding which predictor variables are most relevant. Here we describe a new study in which we investigated an alternative Bayesian regression approach applied to the same case study. We compare the two models in terms of their inner workings, results, and interpretive utility. We also use an updated database of Angkorian temples as the training dataset, allowing us to produce the most current estimate for temple foundations and historic spatiotemporal urban growth patterns at Angkor. Our results demonstrate that, in principle, predictive statistical and machine learning methods could be used to rapidly add chronological information to large lidar datasets and a Bayesian paradigm makes it possible to incorporate important uncertainties—especially chronological—into modelled temporal estimates.

A latitudinal gradient in Darwin’s naturalization conundrum at the global scale for flowering plants

Darwin’s naturalization conundrum describes two seemingly contradictory hypotheses regarding whether alien species closely or distantly related to native species should be more likely to naturalize in regional floras. Both expectations have accumulated empirical support, and whether such apparent inconsistency can be reconciled at the global scale is unclear. Here, using 219,520 native and 9,531 naturalized alien plant species across 487 globally distributed regions, we found a latitudinal gradient in Darwin’s naturalization conundrum. Naturalized alien plant species are more closely related to native species at higher latitudes than they are at lower latitudes, indicating a greater influence of preadaptation in harsher climates. Human landscape modification resulted in even steeper latitudinal clines by selecting aliens distantly related to natives in warmer and drier regions. Our results demonstrate that joint consideration of climatic and anthropogenic conditions is critical to reconciling Darwin’s naturalization conundrum.

New Blombos Cave evidence supports a multistep evolutionary scenario for the culturalization of the human body

The emergence of technologies to culturally modify the appearance of the human body is a debated issue, with earliest evidence consisting of perforated marine shells dated between 140 and 60 ka at archaeological sites from Africa and western Asia. In this study, we submit unpublished marine and estuarine gastropods from Blombos Cave Middle Stone Age layers to taxonomic, taphonomic, technological, and use-wear analyses. We show that unperforated and naturally perforated eye-catching shells belonging to the species Semicassis zeylanica, Conus tinianus, and another Conus species, possibly Conus algoensis, were brought to the cave between 100 and 73 ka. At ca. 70 ka, a previously unrecorded marine gastropod, belonging to the species Tritia ovulata, was perforated by pecking and was worn as an ornamental object, isolated or in association with numerous intentionally perforated shells of the species Nassarius kraussianus. Fluctuations in sea level and consequent variations in the site-to-shoreline distances and landscape modifications during the Middle Stone Age have affected the availability of marine shells involved in symbolic practices. During the M3 and M2 Lower phases, with a sea level 50 m lower, the site was approximately 3.5 km away from the coast. In the later M2 Upper and M1 phases, with a sea level at −60 m, the distance increased to about 5.7 km. By the end of the M1 phase, when the site was abandoned, Blombos Cave was situated 18–30 km from the shoreline. We use the new Blombos evidence and a review of the latest findings from Africa and Eurasia to propose a testable ten-step evolutionary scenario for the culturalization of the human body with roots in the deep past.