Recent publications in Zoology and Ecology
Aims: Secondary forests are expanding rapidly in tropical regions and could play an important role in conserving native biodiversity and stabilising global climate. The recovery rate of plant communities in secondary forests varies considerably due to mechanisms associated with seed dispersal and recruitment dynamics. We explored these mechanisms along a chronosequence of tropical secondary forests in an agricultural landscape that was extensively cleared. Location: We explored these mechanisms along a chronosequence of secondary forests in tropical Australia. Methods: We used selected plant traits to characterise plant species and compared community composition between demographic stages (i.e. soil seedbank, understorey and overstorey) and forest age categories. We collected soil samples to assess seedbank composition and used quadrants and transects to assess understorey and overstorey plant community composition at each site. Results: For all demographic stages, we found that young (4-12 years) and intermediate-aged forests (16-20 years) were dominated by early successional, small-seeded species and traits associated with disturbed forests. In old secondary forest (23-34 years) some traits associated with late successional stages were present (e.g. large seeds, trees). However, the traits and species composition of mature forests remained distinct from all secondary forests. Across the chronosequence, forest age and demographic stage were significant factors in discriminating species and trait composition between forest sites. We found clear plant community similarities within demographic stages, despite the forest age differences. This suggests stronger limitations to dispersal and recruitment between demographic stages than between forest ages. Conclusions: Our results show that secondary forests in this region assemble slowly with dispersal and recruitment limitations constraining their recovery. Although a successional transition in species and plant traits composition along the chronosequence is clear, similarities to mature forests remain low. The slow recovery of late successional and large-seeded species in these secondary forests suggests that active restoration of such species may be necessary if we want to enhance the capacity of these forests to conserve native biodiversity.
Mukul, Sharif A., Huq, Saleemul, Herbohn, John, Seddon, Nathalie, and Laurance, William F. (2020) Saving the Sundarbans from development. Science, 368 (6496). p. 1198.
[Extract:] To protect the Sundarbans, any development in the region should also comply with policies that conserve local ecosystems and livelihoods.
Van Oosterzee, Penny, and Laurance, Bill (2020) The next global pandemic could easily erupt in your backyard. The Conversation.
[Extract:] We know the virus that causes COVID-19 is linked to very similar viruses in bats, possibly passed to humans via an intermediate species such as pangolins. The chance of a similar pandemic breaking out in Australia might seem far-fetched. But in fact, we tick all the boxes.
Alamgir, Mohammed, Campbell, Mason J., Sloan, Sean, Engert, Jayden, Word, Jettie, and Laurance, William F. (2020) Emerging challenges for sustainable development and forest conservation in Sarawak, Borneo. PLoS ONE, 15 (3). e0229614.
The forests of Borneo—the third largest island on the planet—sustain some of the highest biodiversity and carbon storage in the world. The forests also provide vital ecosystem services and livelihood support for millions of people in the region, including many indigenous communities. The Pan-Borneo Highway and several hydroelectric dams are planned or already under construction in Sarawak, a Malaysian state comprising part of the Borneo. This development seeks to enhance economic growth and regional connectivity, support community access to services, and promote industrial development. However, the implications of the development of highway and dams for forest integrity, biodiversity and ecosystem services remained largely unreported. We assessed these development projects using fine-scale biophysical and environmental data and found several environmental and socioeconomic risks associated with the projects. The highway and hydroelectric dam projects will impact 32 protected areas including numerous key habitats of threatened species such as the proboscis monkey (Nasalis larvatus), Sarawak surili (Presbytis chrysomelas), Bornean orangutans (Pongo pygmaeus) and tufted ground squirrel (Rheithrosciurus macrotis). Under its slated development trajectory, the local and trans-national forest connectivity between Malaysian Borneo and Indonesian Borneo would also be substantially diminished. Nearly ~161 km of the Pan-Borneo Highway in Sarawak will traverse forested landscapes and ~55 km will traverse carbon-rich peatlands. The 13 hydroelectric dam projects will collectively impact ~1.7 million ha of forest in Sarawak. The consequences of planned highway and hydroelectric dams construction will increase the carbon footprint of development in the region. Moreover, many new road segments and hydroelectric dams would be built on steep slopes in high-rainfall zones and forested areas, increasing both construction and ongoing maintenance costs. The projects would also alter livelihood activities of downstream communities, risking their long-term sustainability. Overall, our findings identify major economic, social and environmental risks for several planned road segments in Sarawak—such as those between Telok Melano and Kuching; Sibu and Bintulu; and in the Lambir, Limbang and Lawas regions—and dam projects—such as Tutoh, Limbang, Lawas, Baram, Linau, Ulu Air and Baleh dams. Such projects need to be reviewed to ensure they reflect Borneo’s unique environmental and forest ecosystem values, the aspirations of local communities and long-term sustainability of the projects rather than being assessed solely on their short term economic returns.
Munksgaard, Niels C., Zwart, Costijn, Haig, Jordahna, Cernusak, Lucas A., and Bird, Michael I. (2020) Coupled rainfall and water vapour stable isotope time series reveal tropical atmospheric processes on multiple timescales. Hydrological Processes, 34 (1). pp. 111-124.
High-frequency stable isotope data are useful for validating atmospheric moisture circulation models and provide improved understanding of the mechanisms controlling isotopic compositions in tropical rainfall. Here, we present a near-continuous 6-month record of O- and H-isotope compositions in both water vapour and daily rainfall from Northeast Australia measured by laser spectroscopy. The data set spans both wet and dry seasons to help address a significant data and knowledge gap in the southern hemisphere tropics. We interpret the isotopic records for water vapour and rainfall in the context of contemporaneous meteorological observations. Surface air moisture provided near-continuous tracking of the links between isotopic variations and meteorological events on local to regional spatial scales. Power spectrum analysis of the isotopic variation showed a range of significant periodicities, from hourly to monthly scales, and cross-wavelet analysis identified significant regions of common power for hourly averaged water vapour isotopic composition and relative humidity, wind direction, and solar radiation. Relative humidity had the greatest subdiurnal influence on isotopic composition. On longer timescales (weeks to months), isotope variability was strongly correlated with both wind direction and relative humidity. The high-frequency records showed diurnal isotopic variations in O- and H-isotope compositions due to local dew formation and, for deuterium excess, as a result of evapotranspiration. Several significant negative isotope anomalies on a daily scale were associated with the activity of regional mesoscale convective systems and the occurrence of two tropical cyclones. Calculated air parcel back trajectories identified the predominant moisture transport paths from the Southwest Pacific Ocean, whereas moisture transport from northerly directions occurred mainly during the wet season monsoonal airflow. Water vapour isotope compositions reflected the same meteorological events as recorded in rainfall isotopes but provided much more detailed and continuous information on atmospheric moisture cycling than the intermittent isotopic record provided by rainfall. Improved global coverage of stable isotope data for atmospheric water vapour is likely to improve simulations of future changes to climate drivers of the hydrological cycle.
Perrie, Leon R., Shepherd, Lara D., Field, Ashley R., and Brownsey, Patrick J. (2020) Morphological and genetic evidence for the separation of Phlegmariurus billardierei from P. varius (Lycopodiaceae). New Zealand Journal of Botany, 58 (2). pp. 118-128.
Phlegmariurus varius is an Australasian species of lycophyte that has long been recognised as morphologically and ecologically variable. A recent study reported incongruence between morphological and genetic variation within New Zealand samples. However, a reappraisal and repeat of the genetic analyses of chloroplast DNA sequence data, and a more detailed examination of morphological variation, strongly supports the recognition of two species that are sympatric in New Zealand. The combination Phlegmariurus billardierei (Spring) Brownsey & Perrie is made here for plants with distinct strobili. The other species, Phlegmariurus varius (R.Br.) A.R.Field & Bostock sensu stricto, has comparatively indistinct strobili, and remains morphologically and ecologically variable even after the segregation of P. billardierei. Phlegmariurus varius is indigenous to both Australia and New Zealand, while P. billardierei is the only species of Lycopodiaceae endemic to New Zealand.
Weimerskirch, Henri, de Grissac, Sophie, Ravache, Andreas, Prudor, Aurélien, Corbeau, Alexandre, Congdon, Bradley C., McDuie, Fiona, Bourgeois, Karen, Dromzée, Sylvain, Butscher, John, Menkes, Christophe, Alain, Valérie, Vidal, Eric, Jaeger, Audrey, and Borsa, Philippe (2020) At-sea movements of wedge-tailed shearwaters during and outside the breeding season from four colonies in New Caledonia. Marine Ecology Progress Series, 633. pp. 225-238.
The wedge-tailed shearwater (WTS) population of New Caledonia is one of the largest in the world, yet its biology and foraging ecology are poorly known. We studied WTS from 4colonies in New Caledonia. We examined foraging behaviour and habitats using GPS receivers and light sensors during and outside the breeding season, respectively, and compared our findings with those from other WTS populations worldwide. During breeding, New Caledonian WTS alternated short foraging trips close to the colony over the lagoon, or off the reef edge, with longer trips overdistant, deep waters. Whereas neighboring colonies overlapped at sea, especially during short trips,there was a clear separation of foraging zones between the pairs of colonies located in the southern versus northwestern parts of New Caledonia. Although WTS actively foraged and commuted to for-aging zones during the day, they mainly returned to the colony or rested at night, indicating that they feed mainly during the day. Active foraging did not take place in more productive areas, suggesting that it may instead be related to the presence of sub-surface predators. Outside the breeding season, birds from 3 colonies had similar trans-equatorial migratory behaviour. All left New Caledonia at the same time of the year with a fast, northeasterly movement and wintered over deep waters in the same sector of the northwestern tropical Pacific Ocean. At overwintering sites, they spent most of their non-foraging time presumably sitting on the water, especially at night, making a slow westward movement before returning to New Caledonia. WTS from New Caledonia forage over warm, oligotrophic deep waters throughout their life cycle, and the species appears to have a flexible foraging strategy adapted to the various environmental conditions encountered across it swide tropical range.
Gely, Claire, Laurance, Susan G.W., and Stork, Nigel E. (2020) How do herbivorous insects respond to drought stress in trees? Biological Reviews, 95. pp. 434-448.
Increased frequency and severity of drought, as a result of climate change, is expected to drive critical changes in plant-insect interactions that may elevate rates of tree mortality. The mechanisms that link water stress in plants to insect performance are not well understood. Here, we build on previous reviews and develop a framework that incorporates the severity and longevity of drought and captures the plant physiological adjustments that follow moderate and severe drought. Using this framework, we investigate in greater depth how insect performance responds to increasing drought severity for: (i) different feeding guilds; (ii) flush feeders and senescence feeders; (iii) specialist and generalist insect herbivores; and (iv) temperate versus tropical forest communities. We outline how intermittent and moderate drought can result in increases of carbon-based and nitrogen-based chemical defences, whereas long and severe drought events can result in decreases in plant secondary defence compounds. We predict that different herbivore feeding guilds will show different but predictable responses to drought events, with most feeding guilds being negatively affected by water stress, with the exception of wood borers and bark beetles during severe drought and sap-sucking insects and leaf miners during moderate and intermittent drought. Time of feeding and host specificity are important considerations. Some insects, regardless of feeding guild, prefer to feed on younger tissues from leaf flush, whereas others are adapted to feed on senescing tissues of severely stressed trees. We argue that moderate water stress could benefit specialist insect herbivores, while generalists might prefer severe drought conditions. Current evidence suggests that insect outbreaks are shorter and more spatially restricted in tropical than in temperate forests. We suggest that future research on the impact of drought on insect communities should include (i) assessing how drought-induced changes in various plant traits, such as secondary compound concentrations and leaf water potential, affect herbivores; (ii) food web implications for other insects and those that feed on them; and (iii) interactions between the effects on insects of increasing drought and other forms of environmental change including rising temperatures and CO2 levels. There is a need for larger, temperate and tropical forest-scale drought experiments to look at herbivorous insect responses and their role in tree death.
Rowell, Misha K., and Rymer, Tasmin L. (2020) Innovation in a native Australian rodent, the fawn-footed mosaic-tailed rat (Melomys cervinipes). Animal Cognition, 23 (2). pp. 301-310.
Innovation is the ability to use a new behaviour, or use an existing behaviour in a new context. Innovation, as an aspect of behavioural flexibility, could be important for allowing animals to cope with rapid environmental changes. Surprisingly, few studies have focused on how innovation ability is affected by task complexity. We investigated innovation ability across multiple tasks of varying complexity in a native Australian rodent, the fawn-footed mosaic-tailed rat (Melomys cervinipes). We predicted that mosaic-tailed rats would be capable of innovating because they live in complex habitats and can exploit disturbed and changing environments. However, we also predicted that the success rate of innovating would decrease as task complexity increased. Mosaic-tailed rats were exposed to six novel problems: cylinder, matchbox, obstruction test, pillar, tile and lever (the last three presented in a Trixie dog activity board), which represented increasing complexity. We counted the number of individuals that could solve at least one task, compared individuals for solving efficiency and latency to solve, and compared the solving success of each task. All mosaic-tailed rats could innovate. However, solving success differed between individuals, with some solving every task and others only solving one. Solving success rate was significantly higher in the simplest task (pillar) compared to the most complicated task (lever). There was no effect of sex or sampling condition on innovation. This study is the first to demonstrate innovation ability across task complexity in an Australian rodent and provides promising avenues for future studies of innovation.
Mahmoud, Mahmoud I., Campbell, Mason J., Sloan, Sean, Alamgir, Mohammed, and Laurance, William F. (2020) Land-cover change threatens tropical forests and biodiversity in the Littoral Region, Cameroon. Oryx. (In Press)
Tropical forest regions in equatorial Africa are threatened with degradation, deforestation and biodiversity loss as a result of land-cover change. We investigated historical land-cover dynamics in unprotected forested areas of the Littoral Region in south-western Cameroon during 1975–2017, to detect changes that may influence this important biodiversity and wildlife area. Processed Landsat imagery was used to map and monitor changes in land use and land cover. From 1975 to 2017 the area of high-value forest landscapes decreased by c. 420,000 ha, and increasing forest fragmentation caused a decline of c. 12% in the largest patch index. Conversely, disturbed vegetation, cleared areas and urban areas all expanded in extent, by 32% (c. 400,000 ha), 5.6% (c. 26,800 ha) and 6.6% (c. 78,631 ha), respectively. The greatest increase was in the area converted to oil palm plantations (c. 26,893 ha), followed by logging and land clearing (c. 34,838 ha), all of which were the major factors driving deforestation in the study area. Our findings highlight the increasing threats facing the wider Littoral Region, which includes Mount Nlonako and Ebo Forest, both of which are critical areas for regional conservation and the latter a proposed National Park and the only sizable area of intact forest in the region. Intact forest in the Littoral Region, and in particular at Ebo, merits urgent protection.
Henderson, Christopher J., Gilby, Ben L., Schlacher, Thomas A., Connolly, Rod M., Sheaves, Marcus, Maxwell, Paul S., Flint, Nicole, Borland, Hayden P., Martin, Tyson S.H., and Olds, Andrew D. (2020) Low redundancy and complementarity shape ecosystem functioning in a low-diversity ecosystem. Journal of Animal Ecology, 89. pp. 784-794.
Ecosystem functioning is positively linked to biodiversity on land and in the sea. In high-diversity systems (e.g. coral reefs), species coexist by sharing resources and providing similar functions at different temporal or spatial scales. How species combine to deliver the ecological function they provide is pivotal for maintaining the structure, functioning and resilience of some ecosystems, but the significance of this is rarely examined in low-diversity systems such as estuaries. We tested whether an ecological function is shaped by biodiversity in a low-diversity ecosystem by measuring the consumption of carrion by estuarine scavengers. Carrion (e.g. decaying animal flesh) is opportunistically fed on by a large number of species across numerous ecosystems. Estuaries were chosen as the model system because carrion consumption is a pivotal ecological function in coastal seascapes, and estuaries are thought to support diverse scavenger assemblages, which are modified by changes in water quality and the urbanization of estuarine shorelines. We used baited underwater video arrays to record scavengers and measure the rate at which carrion was consumed by fish in 39 estuaries across 1,000 km of coastline in eastern Australia. Carrion consumption was positively correlated with the abundance of only one species, yellowfin bream Acanthopagrus australis, which consumed 58% of all deployed carrion. The consumption of carrion by yellowfin bream was greatest in urban estuaries with moderately hardened shorelines (20%-60%) and relatively large subtidal rock bars (>0.1 km(2)). Our findings demonstrate that an ecological function can be maintained across estuarine seascapes despite both limited redundancy (i.e. dominated by one species) and complementarity (i.e. there is no spatial context where the function is delivered significantly when yellowfin bream are not present) in the functional traits of animal assemblages. The continued functioning of estuaries, and other low-diversity ecosystems, might therefore not be tightly linked to biodiversity, and we suggest that the preservation of functionally dominant species that maintain functions in these systems could help to improve conservation outcomes for coastal seascapes.
Williams, Stephen E., Hobday, Alistair J., Falconi, Lorena, Hero, Jean-Marc, Holbrook, Neil J., Capon, Samantha, Bond, Nick R., Ling, Scott D., and Hughes, Lesley (2020) Research priorities for natural ecosystems in a changing global climate. Global Change Biology, 26 (2). pp. 410-416.
Climate change poses significant emerging risks to biodiversity, ecosystem function and associated socioecological systems. Adaptation responses must be initiated in parallel with mitigation efforts, but resources are limited. As climate risks are not distributed equally across taxa, ecosystems and processes, strategic prioritization of research that addresses stakeholder-relevant knowledge gaps will accelerate effective uptake into adaptation policy and management action. After a decade of climate change adaptation research within the Australian National Climate Change Adaptation Research Facility, we synthesize the National Adaptation Research Plans for marine, terrestrial and freshwater ecosystems. We identify the key, globally relevant priorities for ongoing research relevant to informing adaptation policy and environmental management aimed at maximizing the resilience of natural ecosystems to climate change. Informed by both global literature and an extensive stakeholder consultation across all ecosystems, sectors and regions in Australia, involving thousands of participants, we suggest 18 priority research topics based on their significance, urgency, technical and economic feasibility, existing knowledge gaps and potential for cobenefits across multiple sectors. These research priorities provide a unified guide for policymakers, funding organizations and researchers to strategically direct resources, maximize stakeholder uptake of resulting knowledge and minimize the impacts of climate change on natural ecosystems. Given the pace of climate change, it is imperative that we inform and accelerate adaptation progress in all regions around the world.
Halbritter, Aud H., De Boeck, Hans J., Eycott, Amy E., Reinsch, Sabine, Robinson, David A., Vicca, Sara, Berauer, Bernd, Christiansen, Casper T., Estiarte, Marc, Grunzweig, Jose M., Gya, Ragnhild, Hansen, Karin, Jentsch, Anke, Lee, Hanna, Linder, Sune, Marshall, John, Penuelas, Josep, Schmidt, Inger Kappel, Stuart-Haentjens, Ellen, Wilfahrt, Peter, Vandvik, Vigdis, Abrantes, Nelson, Almagro, Maria, Althuizen, Inge H. J., Barrio, Isabel C., te Beest, Mariska, Beier, Claus, Beil, Ilka, Berry, Z. Carter, Birkemoe, Tone, Bjerke, Jarle W., Blonder, Benjamin, Blume-Werry, Gesche, Bohrer, Gil, Campos, Isabel, Cernusak, Lucas A., Chojnicki, Bogdan H., Cosby, Bernhard J., Dickman, Lee T., Djukic, Ika, Filella, Iolanda, Fuchslueger, Lucia, Gargallo-Garriga, Albert, Gillespie, Mark A. K., Goldsmith, Gregory R., Gough, Christopher, Halliday, Fletcher W., Hegland, Stein Joar, Hoch, Guenter, Holub, Petr, Jaroszynska, Francesca, Johnson, Daniel M., Jones, Scott B., Kardol, Paul, Keizer, Jan J., Klem, Karel, Konestabo, Heidi S., Kreyling, Juergen, Kroel-Dulay, Gyorgy, Landhausser, Simon M., Larsen, Klaus S., Leblans, Niki, Lebron, Inma, Lehmann, Marco M., Lembrechts, Jonas J., Lenz, Armando, Linstaedter, Anja, Llusia, Joan, Macias-Fauria, Marc, Malyshev, Andrey, Mand, Pille, Marshall, Miles, Matheny, Ashley M., McDowell, Nate, Meier, Ina C., Meinzer, Frederick C., Michaletz, Sean T., Miller, Megan L., Muffler, Lena, Oravec, Michal, Ostonen, Ivika, Porcar-Castell, Albert, Preece, Catherine, Prentice, Iain C., Radujkovic, Dajana, Ravolainen, Virve, Ribbons, Relena, Ruppert, Jan C., Sack, Lawren, Sardans, Jordi, Schindlbacher, Andreas, Scoffoni, Christine, Sigurdsson, Bjarni D., Smart, Simon, Smith, Stuart W., Soper, Fiona, Speed, James D. M., Sverdrup-Thygeson, Anne, Sydenham, Markus A. K., Taghizadeh-Toosi, Arezoo, Telford, Richard J., Tielboerger, Katja, Topper, Joachim P., Urban, Otmar, van der Ploeg, Martine, Van Langenhove, Leandro, Vecerova, Kristyna, Ven, Arne, Verbruggen, Erik, Vik, Unni, Weigel, Robert, Wohlgemuth, Thomas, Wood, Lauren K., Zinnert, Julie, and Zurba, Kamal (2020) The handbook for standardized field and laboratory measurements in terrestrial climate change experiments and observational studies (ClimEx). Methods in Ecology and Evolution, 11 (1). pp. 22-37.
Climate change is a world-wide threat to biodiversity and ecosystem structure, functioning and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate change impacts across the soil-plant-atmosphere continuum. An increasing number of climate change studies are creating new opportunities for meaningful and high-quality generalizations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re-use, synthesis and upscaling. Many of these challenges relate to a lack of an established 'best practice' for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change. To overcome these challenges, we collected best-practice methods emerging from major ecological research networks and experiments, as synthesized by 115 experts from across a wide range of scientific disciplines. Our handbook contains guidance on the selection of response variables for different purposes, protocols for standardized measurements of 66 such response variables and advice on data management. Specifically, we recommend a minimum subset of variables that should be collected in all climate change studies to allow data re-use and synthesis, and give guidance on additional variables critical for different types of synthesis and upscaling. The goal of this community effort is to facilitate awareness of the importance and broader application of standardized methods to promote data re-use, availability, compatibility and transparency. We envision improved research practices that will increase returns on investments in individual research projects, facilitate second-order research outputs and create opportunities for collaboration across scientific communities. Ultimately, this should significantly improve the quality and impact of the science, which is required to fulfil society's needs in a changing world.
Callaghan, Corey T., Roberts, J. Dale, Poore, Alistair G.B., Alford, Ross A., Cogger, Hal, and Rowley, Jodi J.L. (2020) Citizen science data accurately predicts expert-derived species richness at a continental scale when sampling thresholds are met. Biodiversity and Conservation, 29. pp. 1323-1337.
Understanding species richness patterns in time and space is critical for conservation management and ecological analyses. But estimates of species richness for a given place are often imprecise and incomplete, even when derived from expert-validated range maps. The current uptake of citizen science in natural resource management, conservation, and ecology offers great potential for extensive data to define species occurrence and richness patterns in the future. Yet, studies are needed to validate these richness patterns and ensure these data are fit-for-purpose. We compared data from a continental-scale citizen science project-FrogID-with expert-derived range maps to assess how well the former predicts species richness patterns in space. We then investigated how many citizen science submissions are necessary to fully sample the underlying frog community. There was a strong positive association between citizen science species richness estimates and estimates derived from an expert-derived map of frog distributions. An average of 153 citizen science submissions were necessary to fully-sample frog richness based on the expert-derived frog richness. Sampling effort in the citizen science project was negatively correlated with the remoteness of an area: less remote areas were more likely to have a greater number of citizen science submissions and be fully sampled. This suggests that scientists will likely need to rely on professionals for data collection in remote regions. We conclude that a citizen science project that has been running for similar to 18 months, can accurately predict frog species richness at a continental scale compared with an expert-derived map based on similar to 240 years of data accumulation. At large-scales, biodiversity data derived from citizen science projects will likely play a prominent role in the future of biodiversity and conservation.
Stevenson, Lisa A., Roznik, Elizabeth A., Greenspan, Sasha E., Alford, Ross A., and Pike, David A. (2020) Host thermoregulatory constraints predict growth of an amphibian chytrid pathogen (Batrachochytrium dendrobatidis). Journal of Thermal Biology, 87. 102472.
1. The course and outcome of many wildlife diseases are context-dependent, and therefore change depending on the behaviour of hosts and environmental response of the pathogen. 2. Contemporary declines in amphibian populations are widely attributed to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis. Despite the thermal sensitivity of the pathogen and its amphibian hosts, we do not understand how host thermal regimes experienced by frogs in the wild directly influence pathogen growth. 3. We tested how thermal regimes experienced by the rainforest frog Litoria rheocola in the wild influence pathogen growth in the laboratory, and whether these responses differ from pathogen growth under available environmental thermal regimes. 4. Frog thermal regimes mimicked in the laboratory accelerated pathogen growth during conditions representative of winter at high elevations more so than if temperatures matched air or stream water temperatures. By contrast, winter frog thermal regimes at low elevations slowed pathogen growth relative to air temperatures, but not water temperatures. 5. The growth pattern of the fungus under frog thermal regimes matches field prevalence and intensity of infections for this species (high elevation winter > high elevation summer > low elevation winter > low elevation summer), whereas pathogen growth trajectories under environmental temperatures did not match these patterns. 6. If these laboratory results translate into field responses, tropical frogs may be able to reduce disease impacts by regulating their body temperatures to limit pathogen growth (e.g., by using microhabitats that facilitate basking to reach high temperatures); in other cases, the environment may limit the ability of frogs to thermoregulate such that individuals are more vulnerable to this pathogen (e.g., in dense forests at high elevations). 7. Species-specific thermoregulatory behaviour, and interactions with and constraints imposed by the environment, are therefore essential to understanding and predicting the spatial and temporal impacts of this global disease.
Riggs, Rebecca A., Langston, James D., Sayer, Jeffrey, Sloan, Sean, and Laurance, William F. (2020) Learning from local perceptions for strategic road development in Cambodia's protected forests. Tropical Conservation Science, 13. pp. 1-16.
Road development in tropical forest landscapes is contentious. Local preferences are often subordinated to global economic and environmental concerns. Opportunities to seek solutions based on local context are rare. We examined local perspectives on road development within Cambodia's Keo Seima Wildlife Sanctuary to explore opportunities for optimizing conservation and development outcomes. We conducted household surveys to document the perceived benefits and risks of road development. We found that in the sanctuary, road rehabilitation may accelerate transitions to intensified agriculture and diversified, off-farm incomes. All households prefer good roads and poorer households prioritize road development over other village infrastructure. Households perceive the most prominent benefit of roads to be access to hospital. Local government authorities are responsible for controlling land use and conversion within village boundaries and are therefore highly influential in determining the social and environmental outcomes of roads. Strategies to mitigate environmental risks of roads without constraining development benefits must focus on improving local capacity for decision-making and transparency. Local institutions in tropical forest landscapes must have greater control over development benefits if they are to reinvest assets to achieve conservation success.
Guerra, Angelica, Reis, Leticia Koutchin, Gomes Borges, Felipe Luis, Alves Ojeda, Paula Thais, Manrique Pineda, Daniel Armando, Miranda, Camila Olivera, Furtado de Lima Maidana, Debora Porfiria, Rocha dos Santos, Thiago Mateus, Shibuya, Patricia Sayuri, Marques, Marcia C.M., Laurance, Susan G.W., and Garcia, Leticia Couto (2020) Ecological restoration in Brazilian biomes: Identifying advances and gaps. Forest Ecology and Management, 458. 117802.
The Bonn challenge aims at the restoration of 350 million hectares of degraded ladscapes by 2030. In Brazil, the restoration goal for 2030 is 12 million hectares. Despite the great demand for ecological restoration across the whole of Brazil, there have been no analyses of the studies carried out in different biomes. In addition, conservation efforts must cover all biomes, so that different regions can take advantage of the many benefits of restoration. Our aim was to identify advances and gaps in current restoration knowledge in order to guide future efforts in Brazil. Our bibliometric survey in the Web of Science using 23 keywords related to restoration generated a total of 530 papers, of which 291 were included in the analysis. The papers were published in 121 scientific journals between 1988 and 2018, with the largest number of papers in 2016. The Atlantic Forest was the biome with the highest number of studies, as it is one of the most threatened tropical forest regions in the world and maintains the largest number of research institutions and receives the highest level of funding support in the country. Regarding the types of studies, temporal monitoring was more frequent in the Amazon, Cerrado, Castings, and Pampa, while the monitoring at one point in time was more frequent in the Atlantic Forest. From the studies examined, 31% used a reference area for comparing restoration success. The most studied organisms were plants (81%), and among them, trees were the most frequent, followed by fungi, birds, invertebrates, mammals, and reptiles. The pre-restoration degradation differed among biomes, with deforestation for logging the most cited in the Amazon, agriculture, and livestock in the Atlantic Forest and Cerrado, logging and cattle ranching in Caatinga, and livestock in the Pampa and Pantanal. In general, active/assisted natural succession was the most frequent restoration process: planting seedlings more readily occurred in the Amazon, Atlantic Forest, and Caatinga, whereas natural regeneration in the Cerrado and Pantanal and sowing in Pampa. The studies varied among the age of restoration ( > 1 to 67 years for active restoration and > 1 to 120 years for passive/unassisted natural succession), and the number of species planted (1 to 121 species). We identified an important regional knowledge gap for the Pantanal, Caatinga, and Pampa, as well as the need to include reference areas, evaluate different restoration techniques (besides planting seedlings), and the inclusion of other taxa and life forms in biodiversity studies apart from trees. We also identified the need to expand research to assess landscape metrics, prioritization, legislation, and public policies.
Hirsch, Ben T., Malpass, Erica, and Di Blanco, Yamil E. (2020) Interindividual spacing affects the finder’s share in ring-tailed coatis (Nasua nasua). Behavioral Ecology, 31 (1). pp. 232-238.
Social foraging models are often used to explain how group size can affect an individual’s food intake rate and foraging strategies. The proportion of food eaten before the arrival of conspecifics, the finder’s share, is hypothesized to play a major role in shaping group geometry, foraging strategy, and feeding competition. The variables that affect the finder’s share in ring-tailed coatis were tested using a series of food trials. The number of grapes in the food trials had a strong negative effect on the finder’s share and the probability that the finder was joined. The effect of group size on the finder’s share and foraging success was not straightforward and was mediated by sociospatial factors. The finder’s share increased when the time to arrival of the next individual was longer, the group was more spread out, and the finder was in the back of the group. Similarly, the total amount of food eaten at a trial was higher when more grapes were placed, arrival time was longer, and the number of joiners was smaller. Individuals at the front edge of the group found far more food trials, but foraging success was higher at the back of the group where there were fewer conspecifics to join them. This study highlights the importance of social spacing strategies and group geometry on animal foraging tactics and the costs and benefits of sociality.
Ruaro, Renata, Laurance, William, and Mormul, Roger Paulo (2020) Brazilian national parks at risk. Science, 367 (6481). p. 990.
Brazilian citizens and decision-makers must consider the consequences of such bills for Brazilian national parks and make their concerns about irreversible environmental impacts known to policymakers.
Choi, Young-Jun, Fontenla, Santiago, Fischer, Peter U., Le, Thanh Hoa, Costabile, Alicia, Blair, David, Brindley, Paul J., Tort, Jose F., Cabada, Miguel M., and Mitreva, Makedonka (2020) Adaptive radiation of the flukes of the family Fasciolidae inferred from genome-wide comparisons of key species. Molecular Biology and Evolution, 37 (1). pp. 84-99.
Liver and intestinal flukes of the family Fasciolidae cause zoonotic food-borne infections that impact both agriculture and human health throughout the world. Their evolutionary history and the genetic basis underlying their phenotypic and ecological diversity are not well understood. To close that knowledge gap, we compared the whole genomes of Fasciola hepatica, Fasciola gigantica, and Fasciolopsis buski and determined that the split between Fasciolopsis and Fasciola took place similar to 90 Ma in the late Cretaceous period, and that between 65 and 50 Ma an intermediate host switch and a shift from intestinal to hepatic habitats occurred in the Fasciola lineage. The rapid climatic and ecological changes occurring during this period may have contributed to the adaptive radiation of these flukes. Expansion of cathepsins, fatty-acid-binding proteins, protein disulfide-isomerases, and molecular chaperones in the genus Fasciola highlights the significance of excretory-secretory proteins in these liver-dwelling flukes. Fasciola hepatica and Fasciola gigantica diverged similar to 5 Ma near the Miocene-Pliocene boundary that coincides with reduced faunal exchange between Africa and Eurasia. Severe decrease in the effective population size similar to 10ka in Fasciola is consistent with a founder effect associated with its recent global spread through ruminant domestication. G-protein-coupled receptors may have key roles in adaptation of physiology and behavior to new ecological niches. This study has provided novel insights about the genome evolution of these important pathogens, has generated genomic resources to enable development of improved interventions and diagnosis, and has laid a solid foundation for genomic epidemiology to trace drug resistance and to aid surveillance.
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