Diversity in invasive species management networks.

Effective management of invasive species requires collaboration across a range of stakeholders. These stakeholders exhibit diverse attributes such as organisation types, operational scale, objectives, and roles within projects. Identifying the diverse attributes of stakeholders is beneficial for increasing collaboration success while minimising potential conflicts among multiple stakeholders when managing invasive species across landscapes. Despite the increasing number of studies on connections among stakeholders, there is little understanding of the diverse attributes of stakeholders involved in invasive species management. This is a notable gap because the diversity of stakeholders is one of the significant factors that can influence collaboration success. To bridge this knowledge gap, we used a social network approach to identify the attributes of stakeholders that influence their participation in collaborations using a case study of invasive wild pig (Sus scrofa) management in Queensland, Australia. Our findings suggest that even though the overall stakeholder network was diverse, the stakeholder network at the project level exhibited a lack of diversity on average, particularly regarding the scale of operation and type of organisation. In other words, stakeholders are highly likely to form ties in projects involving other stakeholders from similar types of organisations or operational scales. We suggest that targeting a greater diversity of stakeholders across types of organisations and scales of operations might enhance the success of collaborative invasive species management.

Academic publishing requires linguistically inclusive policies.

Scientific knowledge is produced in multiple languages but is predominantly published in English. This practice creates a language barrier to generate and transfer scientific knowledge between communities with diverse linguistic backgrounds, hindering the ability of scholars and communities to address global challenges and achieve diversity and equity in science, technology, engineering and mathematics (STEM). To overcome those barriers, publishers and journals should provide a fair system that supports non-native English speakers and disseminates knowledge across the globe. We surveyed policies of 736 journals in biological sciences to assess their linguistic inclusivity, identify predictors of inclusivity, and propose actions to overcome language barriers in academic publishing. Our assessment revealed a grim landscape where most journals were making minimal efforts to overcome language barriers. The impact factor of journals was negatively associated with adopting a number of inclusive policies whereas ownership by a scientific society tended to have a positive association. Contrary to our expectations, the proportion of both open access articles and editors based in non-English speaking countries did not have a major positive association with the adoption of linguistically inclusive policies. We proposed a set of actions to overcome language barriers in academic publishing, including the renegotiation of power dynamics between publishers and editorial boards.

Collagen Networks under Indentation and Compression Behave Like Cellular Solids.

Simple synthetic and natural hydrogels can be formulated to have elastic moduli that match biological tissues, leading to their widespread application as model systems for tissue engineering, medical device development, and drug delivery vehicles. However, two different hydrogels having the same elastic modulus but differing in microstructure or nanostructure can exhibit drastically different mechanical responses, including their poroelasticity, lubricity, and load bearing capabilities. Here, we investigate the mechanical response of collagen-1 networks to local and bulk compressive loads. We compare these results to the behavior of polyacrylamide, a fundamentally different class of hydrogel network consisting of flexible polymer chains. We find that the high bending rigidity of collagen fibers, which suppresses entropic bending fluctuations and osmotic pressure, facilitates the bulk compression of collagen networks under infinitesimal applied stress. These results are fundamentally different from the behavior of flexible polymer networks in which the entropic thermal fluctuations of the polymer chains result in an osmotic pressure that must first be overcome before bulk compression can occur. Furthermore, we observe minimal transverse strain during the axial loading of collagen networks, a behavior reminiscent of open-celled cellular solids. Inspired by these results, we applied mechanical models of cellular solids to predict the elastic moduli of the collagen networks and found agreement with the moduli values measured through contact indentation. Collectively, these results suggest that unlike flexible polymer networks that are often considered incompressible, collagen hydrogels behave like rigid porous solids that volumetrically compress and expel water rather than spreading laterally under applied normal loads.

How success is evaluated in collaborative invasive species management: A systematic review.

Invasive species are one of the most pressing global challenges for biodiversity and agriculture. They can cause species extinctions, ecosystem alterations, crop damage, and spread harmful diseases across broad regions. Overcoming this challenge requires collaborative management efforts that span multiple land tenures and jurisdictions. Despite evidence on the importance and approaches to collaboration, there is little understanding of how success is evaluated in the invasive species management literature. This is a major gap, considering evaluating success is crucial for enhancing the efficacy of future management projects. To overcome this knowledge gap, we systematically reviewed the published literature to identify the stages at which success is evaluated - that is, the Process stage (collaborative management actions and Processes), Outputs stage (results of management actions to protect environmental, economic, and social values) and Outcomes stage (effects of Outputs on environmental, economic, and social values) of collaborative invasive species management projects. We also assessed what indicators were used to identify success and whether these evaluations vary across different characteristics of collaborative invasive species management. Our literature search detected 1406 papers, of which 58 met our selection criteria. Out of these, the majority of papers evaluated success across two stages (n = 25, 43.1%), whereas only ten (17.2%) papers evaluated success across all stages. Outputs were the most commonly evaluated stage (n = 40, 68.9%). The most widely used indicators of success for these stages included increased collaboration of stakeholders (Process stage), the number of captured/eradicated/controlled invasive species (Outputs stage) and change in biodiversity values, such as the number of threatened species (Outcomes stage). Most indicators of success were environmentally focused. We highlight the need to align the indicators of success and evaluation stages with the fundamental objectives of the projects to increase the effectiveness of evaluations and thereby maximise the benefits of collaborative invasive species management.

The unequal burden of human-wildlife conflict.

Human-wildlife conflict is one of the most pressing sustainable development challenges globally. This is particularly the case where ecologically and economically important wildlife impact the livelihoods of humans. Large carnivores are one such group and their co-occurrence with low-income rural communities often results in real or perceived livestock losses that place increased costs on already impoverished households. Here we show the disparities associated with the vulnerability to conflict arising from large carnivores on cattle (Bos taurus) globally. Across the distribution of 18 large carnivores, we find that the economic vulnerability to predation losses (as measured by impacts to annual per capita income) is between two and eight times higher for households in transitioning and developing economies when compared to developed ones. This potential burden is exacerbated further in developing economies because cattle keepers in these areas produce on average 31% less cattle meat per animal than in developed economies. In the lowest-income areas, our estimates suggest that the loss of a single cow or bull equates to nearly a year and a half of lost calories consumed by a child. Finally, our results show that 82% of carnivore range falls outside protected areas, and five threatened carnivores have over one third of their range located in the most economically sensitive conflict areas. This unequal burden of human-carnivore conflict sheds light on the importance of grappling with multiple and conflicting sustainable development goals: protecting life on land and eliminating poverty and hunger.

Investigating the Sequence Specific Adsorption Behavior of Polypeptides at the Solid/Liquid Interface.

Polymer adsorption at the solid/liquid interface depends not only on the chemical composition of the polymer but also on the specific placement of the monomers along the polymer sequence. However, challenges in designing polymers with well-controlled sequences have limited explorations into the role of polymer sequence on adsorption behavior to molecular simulations. Here, we demonstrate how the sequence control offered by polypeptide synthesis can be utilized to study the effects small changes in polymer sequence have on polymer adsorption behavior at the solid/liquid interface. Through a combination of quartz crystal microbalance with dissipation monitoring and total internal reflection ellipsometry, we study the adsorption behavior of three polypeptides, consisting of 90% lysine and 10% cysteine, onto a gold surface. We find different mechanisms are responsible for the adsorption of polypeptides and the resulting conformation on the surface. The initial adsorption of the polypeptides is driven by electrostatic interactions between the polylysine and the gold surface. Once adsorbed, the cysteine undergoes a thiol-Au reaction with the surface, altering the conformation of the polymer layer. Our findings suggest the conformation of the polypeptide layer is dependent on the placement of the cysteines within the sequence; polypeptide chains with evenly spaced cysteine groups adopt a more tightly bound "train" conformation as compared to polypeptides with closely grouped cysteine groups. We envision that the methodologies presented here to study sequence specific adsorption behaviors using polypeptides could be a valuable tool to complement molecular simulations studies.

Nanoparticle dynamics in hydrogel networks with controlled defects.

The effect of nanoscale defects on nanoparticle dynamics in defective tetra-poly(ethylene glycol) (tetra-PEG) hydrogels is investigated using single particle tracking. In a swollen nearly homogeneous hydrogel, PEG-functionalized quantum dot (QD) probes with a similar hydrodynamic diameter (dh = 15.1 nm) to the mesh size (〈ξs〉 = 16.3 nm), are primarily immobile. As defects are introduced to the network by reaction-tuning, both the percentage of mobile QDs and the size of displacements increase as the number and size of the defects increase with hydrolysis time, although a large portion of the QDs remain immobile. To probe the effect of nanoparticle size on dynamics in defective networks, the transport of dh = 47.1 nm fluorescent polystyrene (PS) and dh = 9.6 nm PEG-functionalized QDs is investigated. The PS nanoparticles are immobile in all hydrogels, even in highly defective networks with an open structure. Conversely, the smaller QDs are more sensitive to perturbations in the network structure with an increased percentage of mobile particles and larger diffusion coefficients compared to the larger QDs and PS nanoparticles. The differences in nanoparticle mobility as a function of size suggests that particles of different sizes probe different length scales of the defects, indicating that metrics such as the confinement ratio alone cannot predict bulk dynamics in these systems. This study provides insight into designing hydrogels with controlled transport properties, with particular importance for degradable hydrogels for drug delivery applications.

Electrochemically deposited molybdenum disulfide surfaces enable polymer adsorption studies using quartz crystal microbalance with dissipation monitoring (QCM-D).

Polymer and small molecules are often used to modify the wettability of mineral surfaces which facilitates the separation of valuable minerals such as molybdenum disulfide (MoS2) from gangue material through the process of froth flotation. By design, traditional methods used in the field for evaluating the separation efficacy of these additives fail to give proper access to adsorption kinetics and molecule conformation, crucial aspects of flotation where contact times may not allow for full thermodynamic equilibrium. Thus, there is a need for alternative methods for evaluating additives that accurately capture these features during the adsorption of additives at the solid/liquid interface. Here, we present a novel method for preparing MoS2 films on quartz crystals used for Quartz Crystal Microbalance with Dissipation (QCM-D) measurements through an electrochemical deposition process. The resulting films exhibit well-controlled structure, composition, and thickness and therefore are ideal for quantifying polymer adsorption. After deposition, the sensors can be annealed without damaging the quartz crystal, resulting in a phase transition of the MoS2 from the as-deposited, amorphous phase to the 2H semiconducting phase. Furthermore, we demonstrate the application of these sensors to study the interactions of additives at the solid/liquid interface by investigating the adsorption of a model polymer, dextran, onto both the amorphous and crystalline MoS2 surfaces. We find that the adsorption rate of dextran onto the amorphous surface is approximately twice as fast as the adsorption onto the annealed surface. These studies demonstrate the ability to gain insight into the short-term kinetics of interaction between molecules and mineral surface, behavior that is key to designing additives with superior separation efficiency.

Unrecognized threat to global soil carbon by a widespread invasive species.

Most of Earth's terrestrial carbon is stored in the soil and can be released as carbon dioxide (CO2 ) when disturbed. Although humans are known to exacerbate soil CO2 emissions through land-use change, we know little about the global carbon footprint of invasive species. We predict the soil area disturbed and resulting CO2 emissions from wild pigs (Sus scrofa), a pervasive human-spread vertebrate that uproots soil. We do this using models of wild pig population density, soil damage, and their effect on soil carbon emissions. Our models suggest that wild pigs are uprooting a median area of 36,214 km2 (mean of 123,517 km2 ) in their non-native range, with a 95% prediction interval (PI) of 14,208 km2 -634,238 km2 . This soil disturbance results in median emissions of 4.9 million metric tonnes (MMT) CO2 per year (equivalent to 1.1 million passenger vehicles or 0.4% of annual emissions from land use, land-use change, and forestry; mean of 16.7 MMT) but that it is highly uncertain (95% PI, 0.3-94 MMT CO2 ) due to variability in wild pig density and soil dynamics. This uncertainty points to an urgent need for more research on the contribution of wild pigs to soil damage, not only for the reduction of anthropogenically related carbon emissions, but also for co-benefits to biodiversity and food security that are crucial for sustainable development.

Invasive wild pigs (Sus scrofa) as a human-mediated source of soil carbon emissions: Uncertainties and future directions.

Invasive wild pigs (Sus scrofa) have been spread by humans outside of their native range and are now established on every continent except Antarctica. Through their uprooting of soil, they affect societal and environmental values. Our recent article explored another threat from their soil disturbance: greenhouse gas emissions (O'Bryan et al., Global Change Biology, 2021). In response to our paper, Don (Global Change Biology, 2021) claims there is no threat to global soil carbon stocks by wild pigs. While we did not investigate soil carbon stocks, we examine uncertainties regarding soil carbon emissions from wild pig uprooting and their implications for management and future research.

Capillary forces drive buckling, plastic deformation, and break-up of 3D printed beams.

Capillary forces acting at the interfaces of soft materials lead to deformations over the scale of the elastocapillary length. When surface stresses exceed a material's yield stress, a plastocapillary effect is expected to arise, resulting in yielding and plastic deformation. Here, we explore the interfacial instabilities of 3D-printed fluid and elastic beams embedded within viscoelastic fluids and elastic solid support materials. Interfacial instabilities are driven by the immiscibility between the paired phases or their solvents. We find that the stability of an embedded structure is predicted from the balance between the yield stress of the elastic solid, τy, the apparent interfacial tension between the materials, γ', and the radius of the beam, r, such that τy > γ'/r. When the capillary forces are sufficiently large, we observe yielding and failure of the 3D printed beams. Furthermore, we observe new coiling and buckling instabilities emerging when elastic beams are embedded within viscous fluid support materials. The coiling behavior appear analogous to elastic rope coiling whereas the buckling instability follows the scaling behavior predicted from Euler-Bernoulli beam theory.

The importance of Indigenous Peoples' lands for the conservation of terrestrial mammals.

Indigenous Peoples' lands cover over one-quarter of Earth's surface, a significant proportion of which is still free from industrial-level human impacts. As a result, Indigenous Peoples and their lands are crucial for the long-term persistence of Earth's biodiversity and ecosystem services. Yet, information on species composition on these lands globally remains largely unknown. We conducted the first comprehensive analysis of terrestrial mammal composition across mapped Indigenous lands based on data on area of habitat (AOH) for 4460 mammal species assessed by the International Union for Conservation of Nature. We overlaid each species' AOH on a current map of Indigenous lands and found that 2695 species (60% of assessed mammals) had ≥10% of their ranges on Indigenous Peoples' lands and 1009 species (23%) had >50% of their ranges on these lands. For threatened species, 473 (47%) occurred on Indigenous lands with 26% having >50% of their habitat on these lands. We also found that 935 mammal species (131 categorized as threatened) had ≥ 10% of their range on Indigenous Peoples' lands that had low human pressure. Our results show how important Indigenous Peoples' lands are to the successful implementation of conservation and sustainable development agendas worldwide.

La Importancia de las Tierras de los Pueblos Indígenas para la Conservación de los Mamíferos Terrestres Resumen Las tierras pertenecientes a pueblos indígenas cubren más de un cuarto de la superficie del planeta, una proporción importante que se encuentra aún libre de impactos humanos a nivel industrial. Como resultado, los pueblos indígenas y sus tierras son cruciales para la persistencia a largo plazo de la biodiversidad en la Tierra y de los servicios ecosistemicos. Sin embargo, la información sobre la composición de especies en estas tierras a nivel mundial todavía permanece desconocida en su mayoría. Realizamos el primer análisis integral de la composición de mamíferos terrestres a lo largo de las tierras indígenas mapeadas con base en los datos sobre el área del hábitat (ADH) de 4,460 especies de mamíferos valorados por la Unión Internacional para la Conservación de la Naturaleza. Sobrepusimos el ADH de cada especie en un mapa actual de tierras indígenas y encontramos que 2,695 especies (60% de los mamíferos valorados) tienen ≥10% de su distribución dentro de tierras de pueblos indígenas y que 1,009 especies (23%) tienen >50% de su distribución dentro de estas tierras. De las especies amenazadas, 473 (47%) ocurrieron en tierras indígenas.También descubrimos que 935 especies de mamíferos (131 categorizadas como amenazadas) tienen ≥ 10% de su distribución dentro de tierras de pueblos indígenas con baja presión humana. Nuestros resultados muestran cuán importantes son las tierras de los pueblos indígenas para la implementación exitosa de la conservación y las agendas globales de desarrollo sustentable.

Correction: 3D aggregation of cells in packed microgel media.

Correction for '3D aggregation of cells in packed microgel media' by Cameron D. Morley et al., Soft Matter, 2020, DOI: 10.1039/d0sm00517g.

3D aggregation of cells in packed microgel media.

In both natural and applied contexts, investigating cell self-assembly and aggregation within controlled 3D environments leads to improved understanding of how structured cell assemblies emerge, what determines their shapes and sizes, and whether their structural features are stable. However, the inherent limits of using solid scaffolding or liquid spheroid culture for this purpose restrict experimental freedom in studies of cell self-assembly. Here we investigate multi-cellular self-assembly using a 3D culture medium made from packed microgels as a bridge between the extremes of solid scaffolds and liquid culture. We find that cells dispersed at different volume fractions in this microgel-based 3D culture media aggregate into clusters of different sizes and shapes, forming large system-spanning networks at the highest cell densities. We find that the transitions between different states of assembly can be controlled by the level of cell-cell cohesion and by the yield stress of the packed microgel environment. Measurements of aggregate fractal dimension show that those with increased cell-cell cohesion are less sphere-like and more irregularly shaped, indicating that cell stickiness inhibits rearrangements in aggregates, in analogy to the assembly of colloids with strong cohesive bonds. Thus, the effective surface tension often expected to emerge from increased cell cohesion is suppressed in this type of cell self-assembly.

Mechanical Characterization of Glandular Acini Using a Micro-indentation Instrument.

The linker of nucleoskeleton and cytoskeleton (LINC) complex is responsible for tethering the nucleus to the cytoskeleton, providing a pathway for the cell's nucleus to sense mechanical signals from the environment. Recently, we explored the role of the LINC complex in the development of glandular epithelial acini, such as those found in kidneys, breasts, and other organs. Acini developed with disrupted LINC complexes exhibited a loss of structural integrity, including filling of the lumen structures. As part of our investigation, we performed a mechanical indentation assay of LINC disrupted and undisrupted MDCK II cells using a micro-indentation instrument mounted above a laser-scanning confocal microscope. Through a combination of force measurements acquired from the micro-indentation instrument and contact area measurements taken from fluorescence images, we determined the average contact pressure at which the acini structure ruptured. Here, we provide a detailed description of the design of the micro-indentation instrument, as well as the experimental steps developed to perform these bio-indentation measurements. Furthermore, we discuss the data analysis steps necessary to determine the rupture pressure of the acini structures. While this protocol is focused on the indentation of individual glandular acini, the methods presented here can be adapted to perform a variety of mechanical indentation experiments for both 2D and 3D biological systems.

Correction: Hotspots of human impact on threatened terrestrial vertebrates.

[This corrects the article DOI: 10.1371/journal.pbio.3000158.].

Anthracene-based mechanophores for compression-activated fluorescence in polymeric networks.

The recent attention given to functionalities that respond to mechanical force has led to a deeper understanding of force transduction and mechanical wear in polymeric materials. Furthermore, polymers have been carefully designed such that activation of "mechanophores" leads to productive outputs, such as material reinforcement or changes in optical properties. In this work, a crosslinker containing an anthracene-maleimide linkage was designed and used to prepare networks that display a fluorescence response when damaged. The pressure-dependent damage of poly(N,N-dimethylacrylamide) networks was monitored using solid-state fluorescence spectroscopy, with increasing compressive forces leading to higher degrees of mechanophore activation. When a stamp was used to compress the networks, only the areas in contact with the raised portion of the stamp underwent mechanophore activation, resulting in the generation of patterns that were only visible under UV light. Finally, an isomeric "flex" mechanophore was designed and used to prepare networks that were compressed and compared to the previously described networks.

Mechanical Stabilization of the Glandular Acinus by Linker of Nucleoskeleton and Cytoskeleton Complex.

The nucleoskeleton and cytoskeleton are important protein networks that govern cellular behavior and are connected together by the linker of nucleoskeleton and cytoskeleton (LINC) complex. Mutations in LINC complex components may be relevant to cancer, but how cell-level changes might translate into tissue-level malignancy is unclear. We used glandular epithelial cells in a three-dimensional culture model to investigate the effect of perturbations of the LINC complex on higher order cellular architecture. We show that inducible LINC complex disruption in human mammary epithelial MCF-10A cells and canine kidney epithelial MDCK II cells mechanically destabilizes the acinus. Lumenal collapse occurs because the acinus is unstable to increased mechanical tension that is caused by upregulation of Rho-kinase-dependent non-muscle myosin II motor activity. These findings provide a potential mechanistic explanation for how disruption of LINC complex may contribute to a loss of tissue structure in glandular epithelia.