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Rats are among the worst invasive alien predators. They prey upon eggs, chicks, and sometimes adults of seabirds, leading to the decline of many populations. Rats have invaded 93% of the islands in the western Indian Ocean, which is an avian biodiversity hotspot. Europa Island, Mozambique Channel, is a major seabird breeding site, where at least 1,000,000 pairs bred at the end of 20th century, including the endemic white-tailed tropicbirds (Phaethon lepturus europae). This species and the red-tailed tropicbird (Phaethon rubricauda) are vulnerable to predation by black rat (Rattus rattus), barn owl (Tyto alba), and pied-crow (Corvus albus) on Europa Island. In this study, we estimate the current population sizes of these tropicbird species and their breeding success. The impact of predators on tropicbird nests was quantified with camera traps. Finally, we model the dynamics of these populations under three management scenarios (no action, complete rat eradication, and targeted control of rats around nests). In 2019, 1,027 pairs of red-tailed and 100 pairs of white-tailed tropicbirds bred on Europa Island, which indicates an annual decline of 5% and 17% since 2009, respectively. Breeding success of red-tailed tropicbirds and white-tailed tropicbirds was extremely low (0.08 ± 0.07 and 0.06 ± 0.03 respectively). Rats were detected at most surveyed nests and were the main predators of eggs and chicks. Pied-crows and barn owls also depredated nests occasionally. Population viability analysis projected a local extinction in 32–85 years for the red-tailed tropicbird, and in 11–50 years for white-tailed tropicbirds without conservation intervention. The complete eradication of rats would result in a rapid recovery of both populations. Rat control around nests only would result in population recovery only if 74% of the nests of white-tailed and 63% of the nests of red-tailed tropicbirds are free of rats.

# Background In 2015, Ethiopia designated rabies as a priority zoonotic disease. Challenges in rabies diagnostic capacity, including laboratory safety, were identified in 2016. As a pilot evaluation, the national rabies laboratory in Ethiopia (EPHI) was chosen to participate in an evaluation of necropsy laboratory facilities and procedures which was conducted over two years. This evaluation identified areas for improvement that strengthening would enhance safety in the laboratory environment. Process changes, specifically in cleaning procedures, will decrease the likelihood of cross contamination and improve precision of testing. # Methods This evaluation consisted of two sections: a 38-question verbal interview and an observational evaluation of necropsy laboratory practice. In March 2018, we evaluated EPHI’s laboratory biosafety procedures, and the laboratory technicians’ knowledge, practices, and attitudes in the animal necropsy laboratory before CDC-led laboratory trainings (September and December 2018). A post-training evaluation was conducted in March 2019. # Results Safety compliance scores in 2019 were noticeably increased from 2018. Interview scores increased from 57% to 91% and laboratory observation scores increased from 74% to 91%. # Conclusion This evaluation revealed that a necropsy laboratory assessment could be a valuable tool for understanding challenges faced by laboratories performing rabies diagnosis in Ethiopia. Assessment materials help to identify on-going challenges as well as areas of improvement in a systematic manner. In the future, this assessment could be used as a model for labs performing rabies diagnosis in a decentralized system. Additional rabies laboratories are anticipated to stand up throughout Ethiopia and laboratory assessments based on this methodology could provide valuable insights into how to mitigate risks.

We explore the development of community-engaged scholars and practitioners through two distinct lenses: faculty who facilitate engaged learning processes and student-practitioners who are enacting these processes in their work. We use an auto-ethnographic technique, our own stories, to describe the will (motivation) and capacity (knowledge) gained through community engagement. More importantly, we provide vivid accounts of marked differences in our teaching, learning, and leadership. As a result, we have become activists in our craft as practitioners and scholars.

Abstract Rapid and broad-scale forest mortality associated with recent droughts, rising temperature, and insect outbreaks has been observed over western North America (NA). Climate models project additional future warming and increasing drought and water stress for this region. To assess future potential changes in vegetation distributions in western NA, the Community Earth System Model (CESM) coupled with its Dynamic Global Vegetation Model (DGVM) was used under the future A2 emissions scenario. To better span uncertainties in future climate, eight sea surface temperature (SST) projections provided by phase 3 of the Coupled Model Intercomparison Project (CMIP3) were employed as boundary conditions. There is a broad consensus among the simulations, despite differences in the simulated climate trajectories across the ensemble, that about half of the needleleaf evergreen tree coverage (from 24% to 11%) will disappear, coincident with a 14% (from 11% to 25%) increase in shrubs and grasses by the end of the twenty-first century in western NA, with most of the change occurring over the latter half of the twenty-first century. The net impact is a ~6 GtC or about 50% decrease in projected ecosystem carbon storage in this region. The findings suggest a potential for a widespread shift from tree-dominated landscapes to shrub and grass-dominated landscapes in western NA because of future warming and consequent increases in water deficits. These results highlight the need for improved process-based understanding of vegetation dynamics, particularly including mortality and the subsequent incorporation of these mechanisms into earth system models to better quantify the vulnerability of western NA forests under climate change.

Study region: India Study focus: India boasts the largest irrigated agricultural system in the world relying on groundwater. To address the strong linkages between the natural groundwater and the anthropogenic irrigated system requires innovative hydrological modeling geared at informing national policies on groundwater management and future development of irrigated agriculture. For this, we developed a predictive, integrated hydrological and groundwater use model and evaluated the model using total water storage (TWS) data from the Gravity Recovery and Climate Experiment (GRACE). The utility of the model was demonstrated in a case study in which the model was applied to project the groundwater balance in northwest India under four RCP (Representative Concentration Pathways) scenarios. New hydrological insights for the region: The model shows good identifiability to GRACE data in northwest India and with incorporated groundwater irrigation simulation module the model can adequately replicate the declining trend in TWS over this region. It is concluded that by assuming a unchanged pattern of agricultural water use climate change is likely to help reduce the magnitude of the groundwater deficit, but the beneficial effect is insufficient to halt the trend of groundwater depletion. This result provides new evidence for the importance of groundwater conservation through changes in cropping patterns and improved groundwater governance.

Abstract India has the second largest population in the world and is characterized by a broad diversity in climate, topography, flora, fauna, land use, and socioeconomic conditions. To help ensure food security in the future, agricultural systems will have to respond to global change drivers such as population growth, changing dietary habits, and climate change. However, alterations of how food is produced in the future may conflict with other UN Sustainable Development Goals (SDGs), such as the protection of land resources and climate change mitigation. It is crucial for decision‐makers to understand potential trade‐offs between these goals to find a balance of human needs and environmental impacts. In this paper, we analyze pathways of agricultural productivity, land use, and land‐cover changes in India until 2030 and their impacts on terrestrial biodiversity and carbon storage. The results show that in order to meet future food production demands, agricultural lands are likely to expand, and existing farmlands need to be intensified. However, both processes will result in biodiversity losses. At the same time, the projections reveal carbon stock increases due to intensification processes and decreases due to conversions of natural land into agriculture. On balance, we find that carbon stocks increase with the scenarios of future agricultural productivity as modeled here. In conclusion, we regard further agricultural intensification as a crucial element to help ensure food security and to slow down the expansion of cropland and pasture. At the same time, policies are required to implement this intensification in a way that minimizes biodiversity losses.

Many patients in radiotherapy carry active implantable medical devices (AIMDs) such as pacemakers or cardioverter defibrillators (ICDs). The influence of the ionizing radiation can lead to failures in the device function. This study presents a tissue-equivalent test environment to investigate the influence of ionizing radiation on AIMDs. The in-vitro test environment is designed to simulate a human torso. Structures such as the heart, lungs, ribs, spinal column and soft tissue are replicated from tissue-equivalent materials to allow realistic treatment planning and to simulate the effect of ionizing radiation on active implants. CT measurements and Monte-Carlo validations have shown that Polytetrafluorethylen (bone), carrageenan (heart), Styrodur (lung) and Biresin® G27 (soft tissue) fulfill all requirements for suitable tissue surrogates. A plug-in unit integrated in the test environment has been designed specifically to allow the placement AIMDs in the phantom at typical positions for implant placement in humans. The dosimetry validation showed that the test environment is applicable in the full treatment planning process.

Intracellular inclusions rich in alpha-synuclein are a hallmark of several neuropathological diseases including Parkinson’s disease (PD). Previously, we reported the structure of alpha-synuclein fibrils (residues 1–121), composed of two protofibrils that are connected via a densely-packed interface formed by residues 50–57 (Guerrero-Ferreira, eLife 218;7:e36402). We here report two new polymorphic atomic structures of alpha-synuclein fibrils termed polymorphs 2a and 2b, at 3.0 Å and 3.4 Å resolution, respectively. These polymorphs show a radically different structure compared to previously reported polymorphs. The new structures have a 10 nm fibril diameter and are composed of two protofilaments which interact via intermolecular salt-bridges between amino acids K45, E57 (polymorph 2a) or E46 (polymorph 2b). The non-amyloid component (NAC) region of alpha-synuclein is fully buried by previously non-described interactions with the N-terminus. A hydrophobic cleft, the location of familial PD mutation sites, and the nature of the protofilament interface now invite to formulate hypotheses about fibril formation, growth and stability.

The structures of amyloid fibres are currently primarily studied through solid state NMR and cryo-EM. Here the authors present a free-standing graphene support device that allows diffraction imaging of non-crystalline amyloid fibrils with single X-ray pulses from an X-ray free-electron laser.

Abstract Background Acoustic properties of vocalizations can vary with the internal state of the caller, and may serve as reliable indicators for a caller’s emotional state, for example to prevent conflicts. Thus, individuals may associate distinct characteristics in acoustic signals of conspecifics with specific social contexts, and adjust their behaviour accordingly to prevent escalation of conflicts. Common ravens (Corvus corax) crowd-forage with individuals of different age classes, sex, and rank, assemble at feeding sites, and engage in agonistic interactions of varying intensity. Attacked individuals frequently utter defensive calls in order to appease the aggressor. Here, we investigated if acoustic properties of defensive calls change with varying levels of aggression, and if bystanders respond to these changes. Results Individuals were more likely to utter defensive calls when the attack involved contact aggression, and when the attacker was higher in rank than the victim. Defensive calls produced during intense conflicts were longer and uttered at higher rates, and showed higher fundamental frequency- and amplitude-related measures than calls uttered during low-intensity aggression, indicating arousal-based changes in defensive calls. Playback experiments showed that ravens were more likely to react in response to defensive calls with higher fundamental frequency by orientating towards the speakers as compared to original calls and calls manipulated in duration. Conclusions Arousal-based changes are encoded in acoustic parameters of defensive calls in attacked ravens, and bystanders in the audience pay attention to the degree of arousal in attacked conspecifics. Our findings imply that common ravens can regulate conflicts with conspecifics by means of vocalizations, and are able to gather social knowledge from conspecific calls.

There is a growing recognition among water resource managers that sustainable watershed management needs to not only account for the diverse ways humans benefit from the environment, but also incorporate the impact of human actions on the natural system. Coupled natural–human system modeling through explicit modeling of both natural and human behavior can help reveal the reciprocal interactions and co-evolution of the natural and human systems. This study develops a spatially scalable, generalized agent-based modeling (ABM) framework consisting of a process-based semi-distributed hydrologic model (SWAT) and a decentralized water system model to simulate the impacts of water resource management decisions that affect the food–water–energy–environment (FWEE) nexus at a watershed scale. Agents within a river basin are geographically delineated based on both political and watershed boundaries and represent key stakeholders of ecosystem services. Agents decide about the priority across three primary water uses: food production, hydropower generation and ecosystem health within their geographical domains. Agents interact with the environment (streamflow) through the SWAT model and interact with other agents through a parameter representing willingness to cooperate. The innovative two-way coupling between the water system model and SWAT enables this framework to fully explore the feedback of human decisions on the environmental dynamics and vice versa. To support non-technical stakeholder interactions, a web-based user interface has been developed that allows for role-play and participatory modeling. The generalized ABM framework is also tested in two key transboundary river basins, the Mekong River basin in Southeast Asia and the Niger River basin in West Africa, where water uses for ecosystem health compete with growing human demands on food and energy resources. We present modeling results for crop production, energy generation and violation of eco-hydrological indicators at both the agent and basin-wide levels to shed light on holistic FWEE management policies in these two basins.

Virtual teams have become a major component in the delivery of online courses at Purdue University Global (PUG) and in higher education in general (Olson, et. al, 2015). To help provide employers with qualified candidates for their talent needs, teamwork has been established as one of the six professional competencies that Purdue University Global (PUG) students are assessed for in all programs. Virtual teams in the classroom have become a major source of student and faculty complaints. This resulted in virtual team projects being removed from some classes. Cross functional working teams were established to review the team project processes. The objective of these teams was to develop recommendations for improving team projects in the curriculum. Initial results showed the main factors impacting student satisfaction with team assignments in the virtual classroom included; poor communication within the team, time schedule issues; and, lack of training for both students and faculty.

AtWRKY70, encoding a WRKY transcription factor, is co-expressed with a set of Arabidopsis genes that share a pattern of RPP4- and RPP7-dependent late upregulation in response to Hyaloperonospora parasitica infection (LURP) genes. We show that AtWRKY70 is required for both full RPP4-mediated resistance and basal defense against H. parasitica. These two defense pathways are related to each other, because they require PAD4 and salicylic acid (SA). RPP7 function, which is independent from PAD4 and SA, is not affected by insertions in AtWRKY70. Although AtWRKY70 is required for RPP4-resistance, it appears not to contribute significantly to RPP4-triggered cell death. Furthermore, our data indicate that AtWRKY70 functions downstream of defense-associated reactive oxygen intermediates and SA. Constitutive and RPP4-induced transcript levels of two other LURP genes are reduced in AtWRKY70 T-DNA mutants, indicating a direct or indirect role for AtWRKY70 in their regulation. We propose that AtWRKY70 is a component of a basal defense mechanism that is boosted by engagement of either RPP4 or RPP7 and is required for RPP4-mediated resistance.

An increase in seismic stations also having microbarographs has led to increased interest in the field of seismoacoustics. A review of the recent advances in this field can be found in Dannemann Dugick et al. (2023). The goal of this note is to draw the attention of the readers of Dannemann Dugick et al. (2023) to several additional interactions between the solid Earth and atmosphere that have not been classically considered in the field of seismoacoustics. The 15 January 2022 Hunga Tonga-Hunga Ha'api eruption produced acoustic gravity waves that were recorded globally. For example, the Lamb wave from this eruption produced early-arriving and long-lasting tsunami waves. This eruption also provided globally recorded coupling of atmospheric modes with solid Earth modes, providing another example of the complex interactions that can occur at the boundary between the atmosphere and the solid Earth. Even in the absence of large atmospheric signals, collocated pressure sensors at seismic stations can be a useful tool for estimating the local substructure, such at VS30 the average shear velocity of the upper 30 m. Finally, at low frequencies, it is possible to use pressure records to correct out atmospheric disturbances recorded on seismometers. We briefly review the aforementioned, nontraditional seismoacoustic topics that we feel are important to consider as part of the full suite of interactions occurring between the solid Earth and atmosphere. [ABSTRACT FROM AUTHOR]

Agricultural development efforts that do not address persistent gender gaps miss opportunities for greater impact. This synthesis reflects on key findings from integrated quantitative and qualitative analyses at the nexus of gender, agricultural development, and climate change. Linked farm household-, intrahousehold-, community-, and institutional-level data highlight significant and nuanced gender differences in adaptive capacity of individuals and communities to respond to climate change. The gender gap is also substantial in exposure to climate change and its impacts, and uptake of new practices that lower vulnerability. Women in agriculture will remain largely neglected by information and service providers unless their differing needs, access to, and control over resources are considered at policy and project design stage. Yet clear guidelines for addressing the needs of both men and women in different environments and agricultural systems are still lacking. Participatory ‘action research’ approaches with a focus on co-learning, and using innovative cell phone or social media-based approaches offer exciting new opportunities. Agricultural development decision-makers and project designers need to ‘design with gender in mind’. Equipping them with tools and knowledge of innovative gender-transformative practices and intervention options and creating accountability for serving women and men will be key.

Multimodal imaging is gaining in importance in the field of personalized medicine and can be described as a current trend in medical imaging diagnostics. The segmentation, classification and analysis of tissue structures is essential. The goal of this study is the evaluation of established segmentation methods on different medical image data sets acquired with different diagnostic procedures. Established segmentation methods were implemented using the latest state of the art and applied to medical image data sets. In order to benchmark the segmentation performance quantitatively, medical image data sets were superimposed with artificial Gaussian noise, and the mis-segmentation as a function of the image SNR or CNR was compared to a gold standard. The evaluation of the image segmentation showed that the best results of pixel-based segmentation (< 3%) can be achieved with methods of machine learning, multithreshold and advanced level-set method - even at high artificial noise (SNR< 18). Finally, the complexity of the object geometry and the contrast of the ROI to the surrounding tissue must also be considered to select the best segmentation algorithm.

Home range, movement, and habitat use of Walleye (Sander vitreus) in Onondaga Lake, New York, were determined using active and passive tracking of ultrasonic-tagged Walleye during the summer and fall of 2010 and 2011. Active tracking included bimonthly location surveys of all resident fish and bimonthly 24-h tracking surveys of individuals. Passive tracking was conducted using stationary receivers that were placed in the outlet and major inlets. Walleye in Onondaga Lake exhibit nomadic characteristics with large hourly and daily movements and extensive home and core ranges. Fish moved significantly farther distances per hour and were suspended over deeper water during the evening than during the day. Walleye core and home ranges were concentrated in the northeastern two-thirds of the lake, and there was substantial use of the outlet throughout the summer and fall by a majority of the tagged Walleye. Our findings support the hypothesis that there is a resident population of Walleye within Onondaga Lake during the summer and fall, but those fish exhibit extensive home ranges that include the Onondaga Lake outlet and likely the Seneca River. These results provide further evidence that distribution and movement of Walleye are determined by lake morphometry and forage base.

As temperatures rise and precipitation patterns change, approaches are needed for early detection of the effects on ecosystems. Macroinvertebrate data collected from 81 sites with multiple habitat kick sampling were compiled for this study. We used a binary logistic regression model to predict the probability of local extinction or range expansion of aquatic macroinvertebrates with changes in temperature and precipitation in watersheds of Castilla-La Mancha, Spain. Aquatic insect families from the following orders were found to be sensitive to an increase in average spring temperatures: Ephemeroptera, Plecoptera, Megaloptera, Trichoptera, Coleoptera and Diptera. Taxa in Ephemeroptera, Trichoptera, Hemiptera and Coleoptera showed negative relationships with minimum (winter) temperature, maximum spring temperature and/or precipitation. One mayfly, Caenis, exhibited a positive relationship with minimum temperature. These results indicate that these aquatic communities are expected to change significantly in the short-term, with the potential to alter stream ecosystem functioning. Mediterranean ecosystems are considered biodiversity hotspots, and biotic communities in freshwater habitats in these areas may be particularly vulnerable to projected increases in temperature and decreases in precipitation. The ability of taxa to withstand these changes will depend on resistance, resilience and dispersal capabilities of the aquatic macroinvertebrates as well as available habitat.

We revisit the challenges and prospects for ocean circulation models following Griffies et al. (2010). Over the past decade, ocean circulation models evolved through improved understanding, numerics, spatial discretization, grid configurations, parameterizations, data assimilation, environmental monitoring, and process-level observations and modeling. Important large scale applications over the last decade are simulations of the Southern Ocean, the Meridional Overturning Circulation and its variability, and regional sea level change. Submesoscale variability is now routinely resolved in process models and permitted in a few global models, and submesoscale effects are parameterized in most global models. The scales where nonhydrostatic effects become important are beginning to be resolved in regional and process models. Coupling to sea ice, ice shelves, and high-resolution atmospheric models has stimulated new ideas and driven improvements in numerics. Observations have provided insight into turbulence and mixing around the globe and its consequences are assessed through perturbed physics models. Relatedly, parameterizations of the mixing and overturning processes in boundary layers and the ocean interior have improved. New diagnostics being used for evaluating models alongside present and novel observations are briefly referenced. The overall goal is summarizing new developments in ocean modeling, including: how new and existing observations can be used, what modeling challenges remain, and how simulations can be used to support observations.

A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-19845-z.

To sustain growing food demand and increasing standard of living, global water use increased by nearly 6 times during the last 100 years, and continues to grow. As water demands get closer and closer to the water availability in many regions, each drop of water becomes increasingly valuable and water must be managed more efficiently and intensively. However, soaring water use worsens water scarcity conditions already prevalent in semi-arid and arid regions, increasing uncertainty for sustainable food production and economic development. Planning for future development and investments requires that we prepare water projections for the future. However, estimations are complicated because the future of the world's waters will be influenced by a combination of environmental, social, economic, and political factors, and there is only limited knowledge and data available about freshwater resources and how they are being used. The Water Futures and Solutions (WFaS) initiative coordinates its work with other ongoing scenario efforts for the sake of establishing a consistent set of new global water scenarios based on the shared socio-economic pathways (SSPs) and the representative concentration pathways (RCPs). The WFaS "fast-track" assessment uses three global water models, namely H08, PCR-GLOBWB, and WaterGAP. This study assesses the state of the art for estimating and projecting water use regionally and globally in a consistent manner. It provides an overview of different approaches, the uncertainty, strengths and weaknesses of the various estimation methods, types of management and policy decisions for which the current estimation methods are useful. We also discuss additional information most needed to be able to improve water use estimates and be able to assess a greater range of management options across the water–energy–climate nexus.

The ever-increasing demand for water, food, and energy is putting unsustainable pressure on natural resources worldwide, often leading to environmental degradation that, in turn, affect water, food, and energy security. The recognition of the complex interlinkages between multiple sectors has led to the creation of various holistic approaches to environmental decision making such as Integrated Natural Resources Management (INRM), Integrated Water Resources Management (IWRM), Virtual Water (VW), Water Footprint (WF) and lately the Food-EnergyEnvironment-Water nexus (WE2F). All these approaches aim to increase resource use efficiency and promote sustainability by increasing the cooperation between traditionally disjoint sectors, and mainly differ by the number and relative weights of the sectors included in their framework. They also suffer from the same face and the same barriers for implementation, some of which may never be fully overcome. The paper discusses the benefits of adopting a WE2F nexus approach in the Upper Niger Basin (UNB) and the Inner Niger Delta (IND), but also the multiple difficulties associated with its practical implementation. IWRM/WE2F initiatives in the UNB/IND such as the BAMGIRE project piloted by Wetlands International and funded by the Dutch Embassy in Mali to secure livelihoods and biodiversity in a changing environment, is taken as an example of partial success in the use of a nexus approach to watershed management. It was shown there are multiple barriers to the operational implementation of the WE2F. However, while a full understanding of all interlinkage between sectors may never be possible, data collection, scientific research and model development can improve our ability to understand the complex system in which we live, and hence take better decisions

Parkinson’s disease is a progressive neuropathological disorder that belongs to the class of synucleinopathies, in which the protein alpha-synuclein is found at abnormally high concentrations in affected neurons. Its hallmark are intracellular inclusions called Lewy bodies and Lewy neurites. We here report the structure of cytotoxic alpha-synuclein fibrils (residues 1–121), determined by cryo-electron microscopy at a resolution of 3.4 Å. Two protofilaments form a polar fibril composed of staggered β-strands. The backbone of residues 38 to 95, including the fibril core and the non-amyloid component region, are well resolved in the EM map. Residues 50–57, containing three of the mutation sites associated with familial synucleinopathies, form the interface between the two protofilaments and contribute to fibril stability. A hydrophobic cleft at one end of the fibril may have implications for fibril elongation, and invites for the design of molecules for diagnosis and treatment of synucleinopathies.

N containing lattice matched 1 eV materials, such as Ga(NAsSb) and (GaIn)(NAs), are discussed as potential solar subcells in a four junction solar cell alongside Ge, GaAs, and (GaIn)P, reaching theoretically conversion efficiencies of around 50 %. The solar subcell with the highest conversion efficiency, consisting of (GaIn)(NAsSb), was grown with molecular beam epitaxy (MBE). The growth of Sb/N containing materials have always been a challenge to metalorganic vapor phase epitaxy (MOVPE), as N incorporation is hindered drastically by even small amounts of Sb if 1,1-dimethylhydrazine is used. This strong N/Sb interaction was not observed by MBE, therefore gas phase reactions in MOVPE are held responsible for the N incorporation drop. In this work we will present a systematic study of Ga(NAsSb) on GaAs grown in MOVPE with the novel N/As precursor di-tertiary-butyl-arsano-amine, as well as triethylgallium and triethylantimony. The achieved 1 eV Ga(NAsSb) material opens up new possibilities for using MOVPE to grow further solar subcells like (GaIn)(NAsSb) or Ga(NAsSb) in the band gap range of 1.0 – 1.1 eV.

Harlequin toads (Atelopus spp.) constitute one of the most threatened amphibian clades worldwide, yet much of their life history remains poorly understood. These anurans are strongly associated with stream environments, which are used for reproduction and occupied by males throughout the year, while only visited by females during the reproduction season. We studied a population of the Atelopus flavescens complex in French Guiana. We describe male population density, habitat use, site fidelity and movement, as well as home range behaviour – all prior to the arrival of females. We also present further natural history observations such as nocturnal resting sites and anecdotal observations of females. Our findings suggest that in this lowland population of Atelopus, males maintain territories for a relatively long time compared to other species. Within them, they acoustically compete for females, which they attempt to clasp for amplexus when they arrive later in the season on their way to the breeding sites. [ABSTRACT FROM AUTHOR]

Animals relying on uncertain, ephemeral and patchy resources have to regularly update their information about profitable sites. For many tropical amphibians, widespread, scattered breeding pools constitute such fluctuating resources. Among tropical amphibians, poison frogs (Dendrobatidae) exhibit some of the most complex spatial and parental behaviors—including territoriality and tadpole transport from terrestrial clutches to ephemeral aquatic deposition sites. Recent studies have revealed that poison frogs rely on spatial memory to successfully navigate through their environment. This raises the question of when and how these frogs gain information about the area and suitable reproductive resources. To investigate the spatial patterns of pool use and to reveal potential explorative behavior, we used telemetry to follow males of the territorial dendrobatid frog Allobates femoralis during tadpole transport and subsequent homing. To elicit exploration, we reduced resource availability experimentally by simulating desiccated deposition sites. We found that tadpole transport is strongly directed towards known deposition sites and that frogs take similar direct paths when returning to their home territory. Frogs move faster during tadpole transport than when homing after the deposition, which probably reflects different risks and costs during these two movement phases. We found no evidence for exploration, neither during transport nor homing, and independent of the availability of deposition sites. We suggest that prospecting during tadpole transport is too risky for the transported offspring as well as for the transporting male. Relying on spatial memory of multiple previously discovered pools appears to be the predominant and successful strategy for the exploitation of reproductive resources in A. femoralis. Our study provides for the first time a detailed description of poison frog movement patterns during tadpole transport and corroborates recent findings on the significance of spatial memory in poison frogs. When these frogs explore and discover new reproductive resources remains unknown.