Understanding the effect of anthropogenic disturbance, and its interaction with carnivores and their prey, is crucial to support the conservation of threatened carnivores, particularly in rapidly ...changing landscapes. Based on systematic camera-trap sampling of four protected areas in Riau Province of central Sumatra, we assessed the habitat occupancy and spatiotemporal overlap between people, potential carnivore prey, and four threatened species of medium-sized or large carnivores: Sumatran tigers (Panthera tigris sumatrae), Malayan sun bears (Helarctos malayanus), dholes (Cuon alpinus), and Sunda clouded leopards (Neofelis diardi). To assess spatial overlap of target species, we used single-species occupancy models and applied a Species Interaction Factor (SIF) to conditional two-species occupancy models. We also used kernel density estimation (KDE) to assess temporal overlap among these species. Our habitat use models showed that altitude (elevation) strongly influenced the occupancy of all large carnivores and potential prey species. Except for Sunda clouded leopards, the occurrence of large carnivore species was positively related to the spatial co-occurrence of humans (SIF > 1). In addition, we found that sun bears and dholes both exhibited high spatial overlap with tigers, and that sun bears alone exhibited high temporal overlap with people. Our findings contribute to an improved understanding of the contemporary ecology of carnivores and their prey in rapidly changing, southeast Asian landscapes. Such knowledge is important to the conservation and recovery of large carnivores in conservation hotspots that are increasingly dominated by humans across Sumatra, as well as globally.
Transparent conducting oxides (TCOs), such as indium tin oxide and zinc oxide, play an important role as electrode materials in organic-semiconductor devices. The properties of the inorganic–organic ...interfacethe offset between the TCO Fermi level and the relevant transport level, the extent to which the organic semiconductor can wet the oxide surface, and the influence of the surface on semiconductor morphologysignificantly affect device performance. This review surveys the literature on TCO modification with phosphonic acids (PAs), which has increasingly been used to engineer these interfacial properties. The first part outlines the relevance of TCO surface modification to organic electronics, surveys methods for the synthesis of PAs, discusses the modes by which they can bind to TCO surfaces, and compares PAs to alternative organic surface modifiers. The next section discusses methods of PA monolayer deposition, the kinetics of monolayer formation, and structural evidence regarding molecular orientation on TCOs. The next sections discuss TCO work-function modification using PAs, tuning of TCO surface energy using PAs, and initiation of polymerizations from TCO-tethered PAs. Finally, studies that examine the use of PA-modified TCOs in organic light-emitting diodes and organic photovoltaics are compared.
Organic and printed electronics technologies require conductors with a work function that is sufficiently low to facilitate the transport of electrons in and out of various optoelectronic devices. We ...show that surface modifiers based on polymers containing simple aliphatic amine groups substantially reduce the work function of conductors including metals, transparent conductive metal oxides, conducting polymers, and graphene. The reduction arises from physisorption of the neutral polymer, which turns the modified conductors into efficient electron-selective electrodes in organic optoelectronic devices. These polymer surface modifiers are processed in air from solution, providing an appealing alternative to chemically reactive low-work function metals. Their use can pave the way to simplified manufacturing of low-cost and large-area organic electronic technologies.
The
2016
–
2018
National Invasive Species Council
(
NISC
)
Management Plan
and Executive Order 13751 call for US federal agencies to foster technology development and application to address invasive ...species and their impacts. This paper complements and draws on an Innovation Summit, review of advanced biotechnologies applicable to invasive species management, and a survey of federal agencies that respond to these high-level directives. We provide an assessment of federal government capacities for the early detection of and rapid response to invasive species (EDRR) through advances in technology application; examples of emerging technologies for the detection, identification, reporting, and response to invasive species; and guidance for fostering further advancements in applicable technologies. Throughout the paper, we provide examples of how federal agencies are applying technologies to improve programmatic effectiveness and cost-efficiencies. We also highlight the outstanding technology-related needs identified by federal agencies to overcome barriers to enacting EDRR. Examples include improvements in research facility infrastructure, data mobilization across a wide range of invasive species parameters (from genetic to landscape scales), promotion of and support for filling key gaps in technological capacity (e.g., portable, field-ready devices with automated capacities), and greater investments in technology prizes and challenge competitions.
The ecology of the jaguarundi is poorly known, so I reviewed the literature for all original data and remarks on jaguarundi observations, ecology, and behaviour, to synthesize what is known about the ...species. Jaguarundis occupy and use a range of habitats with dense undergrowth from northern Mexico to central Argentina, but may be most abundant in seasonal dry, Atlantic, gallery, and mixed grassland/agricultural forest landscapes. Jaguarundis are principally predators of small (sigmodontine) rodents, although other mammals, birds, and squamate reptiles are taken regularly. The vast majority of jaguarundi camera‐trap records occurred during daylight hours (0600 h–1800 h); jaguaurndis are also predominantly terrestrial, although they appear to be capable tree climbers. Home range sizes for jaguarundis vary greatly, but most are ≤25 km²; females' territories may be much smaller than or similar in size to those of males. Males may concentrate movements in one area before shifting to another and, as with other felids, intersexual overlap in habitat use appears to be common. Interference competition may be important in influencing the distribution and ecology of jaguarundis, although their diurnal habits may somewhat mitigate its effect. Conflict between humans and jaguarundis over small livestock may be widespread among rural human communities and is likely to be underreported. Despite this conflict, jaguarundis can persist in agriculturally modified landscapes and small forest fragments. Additional research on local jaguarundi populations from more areas should be a priority to determine the true status of the species.
Humans influence tropical rainforest animals directly via exploitation and indirectly via habitat disturbance. Bushmeat hunting and logging occur extensively in tropical forests and have large ...effects on particular species. But how they alter animal diversity across landscape scales and whether their impacts are correlated across species remain less known. We used spatially widespread measurements of mammal occurrence across Malaysian Borneo and recently developed multispecies hierarchical models to assess the species richness of medium‐ to large‐bodied terrestrial mammals while accounting for imperfect detection of all species. Hunting was associated with 31% lower species richness. Moreover, hunting remained high even where richness was very low, highlighting that hunting pressure persisted even in chronically overhunted areas. Newly logged sites had 11% lower species richness than unlogged sites, but sites logged >10 years previously had richness levels similar to those in old‐growth forest. Hunting was a more serious long‐term threat than logging for 91% of primate and ungulate species. Hunting and logging impacts across species were not correlated across taxa. Negative impacts of hunting were the greatest for common mammalian species, but commonness versus rarity was not related to species‐specific impacts of logging. Direct human impacts appeared highly persistent and lead to defaunation of certain areas. These impacts were particularly severe for species of ecological importance as seed dispersers and herbivores. Indirect impacts were also strong but appeared to attenuate more rapidly than previously thought. The lack of correlation between direct and indirect impacts across species highlights that multifaceted conservation strategies may be needed for mammal conservation in tropical rainforests, Earth's most biodiverse ecosystems.
Aim
Interspecific competition plays a key role in shaping carnivore communities. Top‐down effects can impact the coexistence of superordinate and subordinate competitors and prey across a shared ...landscape. Limited resources, their abundance and diminishing habitats can all exacerbate interspecific competition. Sometimes, behavioural mechanisms or adaptations are critical for subordinate carnivores to coexist with larger species. Here, we investigated the distribution pattern of the striped hyaena (Hyaena hyaena) population with respect to habitat features, sympatric carnivores and their prey species across a large landscape.
Location
Western and Eastern Ghats, India.
Taxon
Striped hyaena.
Methods
We collected presence–absence data for hyaenas, tigers, leopards, dholes and their prey using camera‐trapping and indirect sign surveys. Using a random forest algorithm, we modelled the local distribution of hyaenas as a function of important ecological variables, including climate, domestic prey abundance and the predicted probabilities of occurrence of other large carnivores and their prey.
Results
We found that striped hyaenas were confined to relatively small, discrete areas compared to the three other predators, likely a mechanism for achieving coexistence in the landscape. Our empirical results suggested that hyaenas tend to avoid high occurrence probability areas of their co‐predators at a landscape level but foothold opportunities such as, arid climatic conditions, and prey abundance primarily determined spatial incumbency. Coexistence in an area with low to medium relative abundance of co‐predators offsets the interplay between carcass acquisition and risk associated. The coexistence of species was favoured by altitudinal heterogeneity probably providing denning refugia and also by their preference towards suboptimal thorn forests that sustain a low density of co‐predators.
Main Conclusions
Our study showed a desisting impact of large predators on the distribution of the striped hyaena population. Furthermore, we suggest preventing habitat alteration in suboptimal habitats of large carnivores to facilitate coexistence in a shared landscape.
சுருக்கம்
இரு இனத்திற்கு இடையில் நடக்கும் போட்டி ஊனுண்ணி சமூகங்களை வடிவமைப்பதில் முக்கிய பங்கு வகிக்கிறது. தலைகீழ் நாற்கூம்பு விளைவு பகிரப்பட்ட நிலப்பரப்பில் மேல் நிலை மற்றும் கீழ்நிலை போட்டி இன விலங்குகள் மற்றும் இரை இன விலங்குகளின் சகவாழ்வை பாதிக்கலாம். வரையறுக்கப்பட்ட வளங்கள், அவற்றின் மிகுதி, மற்றும் குறைந்து வரும் வாழ்விடங்கள் அனைத்தும் குறிப்பிட்ட இரு இனத்திற்கு இடையில் நடக்கும் போட்டியை அதிகப்படுத்தலாம். சில நேரங்களில், இன நடத்தை அல்லது தகவமைப்பு ஆகியவை துணை மாமிச உண்ணிகள் இருந்து தொடங்கி பெரிய உயிரினங்களுடன் இணைந்து வாழ்வதற்கு முக்கியமானவை. இந்த ஆய்வுக் கட்டுரையில், வரிக் கழுதைப்புலியின் (ஹைனா ஹைனா), பரவி இருத்தல் முறை மற்றும் எண்ணிக்கையை, அதனின் நிலப்பரப்பில் வாழ்விட அம்சங்கள், சக உண்ணிகள் மற்றும் அவற்றின் இரை இனங்களை வைத்து நாங்கள் ஆராய்ந்தோம். நாங்கள் ஹைனாக்கள், புலிகள், சிறுத்தைகள், செந்நாய் மற்றும் அவற்றின் இரை இன இருப்பு மற்றும் இல்லாத தரவுகளை கேமரா‐ட்ராப் மற்றும் மறைமுக அடையாள ஆய்வுமுறையைப் பயன்படுத்தி சேகரித்தோம். ரேண்டம் ஃபாரஸ்ட் வழிமுறையைப் பயன்படுத்தி, ஹைனாக்களின் குறுநில இருப்பை முக்கியமான சுற்றுச்சூழல் செயல்பாடாக இணைத்து, உடன் தட்பவெப்பநிலை, இரை இன மிகுதி, கணிக்கப்பட்ட பிற பெரிய மாமிச உண்ணிகள் மற்றும் அவற்றின் இரையின இருப்பு ஆகியவற்றை இணைத்து மாதிரிகளை வடிவமைத்தோம். மாதிரிகளை ஒப்பிட்ட தில் வரிக் கழுதைப்புலி மற்றும் பிற மூன்று வேட்டையாடிகளுடன் தனித்துவமான பகுதிகளுக்குள் மட்டுப்படுத்தப்பட்டிருப்பதை கண்டறிந்தோம், இது நிலப்பரப்பில் சகவாழ்வை அடைவதற்கான வழிமுறையாக இருக்கலாம். எங்களுடைய அனுபவபூர்வமா முடிவுகள், வரிக் கழுதைப்புலிகள் நிலப்பரப்பு மட்டத்தில் அவற்றின் சக வேட்டையாடிகளின் அதிக இருப்பை தவிர்க்க முனைகின்றன, ஆனால்வாய்ப்புகளைத்தக்கவைத்துக்கொள்கின்ற, மற்றும் வறண்ட தட்பவெப்ப நிலை மற்றும் இரையின் இருப்புஇடஞ்சார்ந்தநிலைத்தன்மையைதீர்மானிக்கிறது
A spin‐cast method is presented for the formation of phosphonic acid functionalized small molecule layers on solution‐processed ZnO substrates for use as electron collecting interlayers in organic ...photovoltaics. Phosphonic acid interlayers modify the ZnO work function and the charge carrier injection barrier at its interface, resulting in systematic control of V OC in inverted bulk heterojunction solar cells. Surface modification is shown to moderate the need for UV light‐soaking of the ZnO contact layers. Lifetime studies (30 days) indicate stable and improved OPV performance over the unmodified ZnO contact, which show significant increases in charge extraction barriers and series resistance. Results suggest that enhanced stability using small molecule modifiers is due to partial passivation of the oxide surface to molecular oxygen adsorption. Surface passivation while maintaining work function control of a selective interlayer can be employed to improve net efficiency and lifetime of organic photovoltaic devices. The modified cathode work function modulates V
OC via static energetic barriers and modulates contact conductivity by creating reversible and irreversible S‐shape current‐voltage characteristics as a result of kinetic barriers to charge transport.
Deposition of benzyl phosphonic acids and alkanethiol self‐assembled monolayers improve initial device performance, and have beneficial effect at mitigating the light‐soaking effect present after aging inverted architecture organic bulk heterojunction devices incorporating ZnO contact layers in air. The effect of a kinetic/transport barrier and a static energetic barrier resulting in formation of S‐shaped J–V curves is isolated.
The role of work function and thermodynamic selectivity of hole collecting contacts on the origin of open circuit voltage (VOC) in bulk heterojunction organic photovoltaics is examined for ...poly(N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole) (PCDTBT) and 6,6‐phenyl‐C71 butyric acid methyl ester (PC71BM) solar cells. In the absence of a charge selective, electron blocking contact, systematic variation of the work function of the contact directly dictates the VOC, as defined by the energetic separation between the relative Fermi levels for holes and electrons, with little change in the observed dark saturation current, J0. Improving the charge selectivity of the contact through an increased barrier to electron injection from the fullerene in the blend into the hole contact results in a decreased reverse saturation current (decreased J0 and increased shunt resistance, RSH) and improved VOC. Based on these observations, we provide a set of contact design criteria for tuning the VOC in bulk heterojunction organic photovoltaics.
Contact work function and thermodynamic selectivity both play key roles in determining the open circuit voltage in PCDTBT:PC71BM OPVs. Systematically increasing the work function of the contact increases the VOC; adding a selective contact with the same work function further increases the VOC due to a change in the space charge region at the active layer/contact interface.
Habitat corridors are important tools for maintaining connectivity in increasingly fragmented landscapes, but generally they have been considered in single‐species approaches. Corridors intended to ...facilitate the movement of multiple species could increase persistence of entire communities, but at the likely cost of being less efficient for any given species than a corridor intended specifically for that species. There have been few tests of the trade‐offs between single‐ and multispecies corridor approaches. We assessed single‐species and multispecies habitat corridors for 5 threatened mammal species in tropical forests of Borneo. We generated maps of the cost of movement across the landscape for each species based on the species’ local abundance as estimated through hierarchical modeling of camera‐trap data with biophysical and anthropogenic covariates. Elevation influenced local abundance of banded civets (Hemigalus derbyanus) and sun bears (Helarctos malayanus). Increased road density was associated with lower local abundance of Sunda clouded leopards (Neofelis diardi) and higher local abundance of sambar deer (Rusa unicolor). Pig‐tailed macaque (Macaca nemestrina) local abundance was lower in recently logged areas. An all‐species‐combined connectivity scenario with least‐cost paths and 1 km buffers generated total movement costs that were 27% and 23% higher for banded civets and clouded leopards, respectively, than the connectivity scenarios for those species individually. A carnivore multispecies connectivity scenario, however, increased movement cost by 2% for banded civets and clouded leopards. Likewise, an herbivore multispecies scenario provided more effective connectivity than the all‐species‐combined scenario for sambar and macaques. We suggest that multispecies habitat connectivity plans be tailored to groups of ecologically similar, disturbance‐sensitive species to maximize their effectiveness.
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