Recent publications in Zoology and Ecology
The fawn-footed mosaic-tailed rat (Melomys cervinipes) is a common Australian rainforest rodent; however, little is known about the growth or behavioural development of individuals of this species. We raised mosaic-tailed rats in captivity to assess the growth and behavioural development of pups from birth until weaning. Pups developed quickly compared with some other Australian species, and there were no significant differences in growth between males and females, except for anogenital distance. The auditory meatus was open by Postnatal Day 5, and eyes were fully opened by Postnatal Day 9. All behaviours, including righting, locomotion, negative geotaxis, climbing and grip reflex, were fully developed by Postnatal Day 6. These results suggest that mosaic-tailed rats are semiprecocial in their physical and behavioural development compared with some native Australian rodent species that are found in arid environments. As females produce few, relatively well-developed young, the population has a low intrinsic rate of natural increase. This may, however, be offset by mosaic-tailed rats producing more litters per year. Understanding the biology of mosaic-tailed rats in general could provide insights into how rarer precocial species might struggle to increase in population size under increasing disturbances.
Delarue, Emma M.P., Kerr, Sarah E., and Rymer, Tasmin L. (2021) Habitat and sex effects on behaviour in fawn-footed mosaic-tailed rats (Melomys cervinipes). Australian Mammalogy. (In Press)
Habitat complexity reflects resource availability and predation pressure - both factors that influence behaviour. We investigated whether exploratory behaviour and activity varied in fawn-footed mosaic-tailed rats (Melomys cervinipes) from two habitats that were categorised differently based on vegetation. We conducted vegetation surveys to determine structural complexity and vegetation cover, confirming that an abandoned hoop-pine (Araucaria cunninghami) plantation forest was structurally less complex, with lower vegetation cover than a variable secondary rainforest. We then tested mosaic-tailed rats from both sites in four behavioural tests designed to assess exploratory and activity behaviours (open field, novel object, light-dark box, acoustic startle), predicting that rats from the less structurally complex habitat would be less exploratory, and show lower activity. Our results provide some evidence for a contextspecific trade-off between exploratory behaviour and predation risk in rats from the abandoned hoop pine plantation, as rats were less active, and showed a freezing strategy in the light-dark box. We also found context-specific sex differences in behaviour in response to a novel object and sound. Our results suggest that small-scale variation in habitat structure and complexity, as well as sex differences, is associated with variation in behaviour, most likely through effects on resource availability and/or predation risk.
Hopkins, Jaimie M., Higgie, Megan, and Hoskin, Conrad J. (2021) Calling behaviour in the invasive Asian house gecko (Hemidactylus frenatus) and implications for early detection. Wildlife Research. (In Press)
Context. Acoustic communication is common in some animal groups, with an underlying function typically associated with mating or territoriality. Resolving the function of calls is valuable both in terms of understanding the fundamental biology of the species and, potentially, for applied reasons such as detection. Early detection is a key step in exclusion and eradication of invasive species, and calling behaviour can be used in this regard. The Asian house gecko (Hemidactylus frenatus) is one of a minority of lizards that uses acoustic communication. However, despite how conspicuous the call is, its function remains poorly resolved. It is also one of the world's most invasive species, with exclusion via early detection being the key form of control. Aims. The aim was to resolve calling patterns and underlying function of the loud, multiple-chirp call ('chik, chik, chiky') in H. frenatus, in the context of using the results for developing effective methods for detection of new and establishing populations. Methods. The calls of wild H. frenatus were recorded to assess peaks in calling activity. Also, laboratory experiments were performed to determine which individuals call, what causes them to call and the degree of call variation among individuals. Key results. Assessment of calling behaviour in the wild revealed greater calling activity in warmer months, and five- to 10-fold peaks in calling activity at sunset and 30 min before sunrise. Laboratory experiments revealed that calls were uttered exclusively by males and primarily by adults (although juveniles can call). Males called more when they were paired with females as opposed to other males. Calls differed among geckos, including the expected negative correlation between dominant frequency and body size. Conclusions. The results suggest that the multiple-chirp call functions as a territory or sexual broadcast by males, perhaps containing information such as body size. Implications. Detection success can be maximised by performing acoustic surveys (by human or machine) during the calling peaks at 30 min before sunrise and at sunset, particularly during warm nights. However, these surveys will only be effective for detecting adult males. The results also suggest that good quality recordings could potentially be used to identify individual geckos.
Pillay, Neville, and Rymer, Tasmin L. (2021) Sons benefit from paternal care in African striped mice. Developmental Psychobiology. (In Press)
Mammalian paternal care is rare and is often linked to enhanced fitness under particular ecological conditions. The proximate consequences of paternal care on offspring are lacking, however. Here, we tested whether levels of paternal care predict the behavioural, cognitive and physiological development of sons in the naturally paternal African striped mouse (Rhabdomys pumilio). We focused on sons raised in two treatments: biparental (both parents) or uniparental (mother alone) families. We recorded levels of interactions between pups with both parents, and later assessed the behaviour, cognition and physiology of sons at three developmental stages: juvenile, sub-adult and adult (sexual maturity). Sons from biparental families showed (a) reduced anxiety as juveniles; (b) greater exploration and social interaction at different stages; (c) better cognition; and (d) reduced corticosterone concentrations than sons from uniparental families. In contrast, sons from uniparental families showed greater levels of paternal care, although prolactin concentrations did not differ between treatments. Paternal care in striped mice enhances fitness of males. Here, we also show that sons benefit psychologically and physiologically through interactions with their fathers. However, sons also trade-off such benefits against their own paternal care behaviour, suggesting that fathers influence the development of their son's phenotype in complex ways.
Jeffs, Christopher T., Terry, J. Christopher D., Higgie, Megan, Jandová, Anna, Konvičková, Hana, Brown, Joel J., Lue, Chia Hua, Schiffer, Michele, O'Brien, Eleanor, Bridle, Jon, Hrcek, Jan, and Lewis, Owen T. (2021) Molecular analyses reveal consistent food web structure with elevation in rainforest Drosophila – parasitoid communities. Ecography, 44 (3). pp. 403-413.
The analysis of interaction networks across spatial environmental gradients is a powerful approach to investigate the responses of communities to global change. Using a combination of DNA metabarcoding and traditional molecular methods we built bipartite Drosophila-parasitoid food webs from six Australian rainforest sites across gradients spanning 850 m in elevation and 5° Celsius in mean temperature. Our cost-effective hierarchical approach to network reconstruction separated the determination of host frequencies from the detection and quantification of interactions. The food webs comprised 5-9 host and 5-11 parasitoid species at each site, and showed a lower incidence of parasitism at high elevation. Despite considerable turnover in the relative abundance of host Drosophila species, and contrary to some previous results, we did not detect significant changes to fundamental metrics of network structure including nestedness and specialisation with elevation. Advances in community ecology depend on data from a combination of methodological approaches. It is therefore especially valuable to develop model study systems for sets of closely-interacting species that are diverse enough to be representative, yet still amenable to field and laboratory experiments.
Woodworth, Bradley K., Fuller, Richard A., Hemson, Graham, McDougall, Andrew, Congdon, Bradley C., and Low, Matthew (2021) Trends in seabird breeding populations across the Great Barrier Reef. Conservation Biology. (In Press)
The Great Barrier Reef is an iconic ecosystem, known globally for its rich marine biodiversity that includes many thousands of tropical breeding seabirds. Despite indications of localised declines in some seabird species from as early as the mid‐1990s, trends in seabird populations across the Reef have never been quantified. With a long history of human impact and ongoing environmental change, seabirds are likely sentinels in this important ecosystem. Using four decades of monitoring data, we estimated site‐specific trends for nine seabird species from 32 islands and cays across the Reef. Trends varied markedly among species and sites, but probable declines occurred at 45% of the 86 species‐by‐site combinations analysed compared to increases at 14%. For five species we combined site‐specific trends into a multi‐site trend in scaled abundance, which revealed probable declines of common noddy (Anous stolidus), sooty tern (Onychoprion fuscatus), and masked booby (Sula dactylatra), but no long‐term changes in the two most widely distributed species, greater crested tern (Thalasseus bergii) and brown booby (Sula leucogaster). For brown booby, long‐term stability largely resulted from increases at a single large colony on East Fairfax Island that offset declines at a majority of other sites. While growth of the brown booby population at East Fairfax points to the likely success of habitat restoration on the island, it also highlights a general vulnerability wherein large numbers of some species are concentrated at a small number of key sites. Identifying drivers of variation in population change across species and sites while ensuring long‐term protection of key sites will be essential to securing the future of seabirds on the Reef.
Palma, Ana C., Goosem, Miriam, Fensham, Roderick J., Goosem, Steve, Preece, Noel D., Stevenson, Pablo R., and Laurance, Susan G.W. (2021) Dispersal and recruitment limitations in secondary forests. Journal of Vegetation Science. e12975. (In Press)
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.
Yeeles, Peter, Strain, Angela, Lenancker, Pauline, and Lach, Lori (2021) Low reduction of invasive ant colony productivity with an insect growth regulator. Pest Management Science. (In Press)
Background Insect growth regulators (IGRs) generally are considered to have safer eco-toxicological profiles than the more commonly used neurotoxins and metabolic inhibitors, and are extremely effective against several insect groups, including some invasive ant species. However, use of an IGR product in a large-scale eradication program for a widespread invasive ant (Anoploepis gracilipes; yellow crazy ant) was ineffective. We tested the IGR in question (active ingredient: (S)-methoprene) on A. gracilipes colonies in a laboratory environment to evaluate efficacy. Results We found that treatment with (S)-methoprene resulted in lower egg production with subsequently decreased numbers of larvae, pupae, and workers over the 135 days of the experiment. None of the treated colonies died, and the number of worker ants in treated colonies was 36% of that seen in control colonies 135 days post-treatment. Treated queen egg production was 39% lower than queens in control colonies, but we saw no effect of treatment on the internal physiology of dissected queens. Treatment had no effect on worker activity levels. Conclusion Our results show that although (S)-methoprene treatment reduced production of larvae, pupae and workers in treated colonies, the magnitude of reduction was lower than might be expected considering the responses of other species against which this IGR has been tested. Our findings highlight a need for testing species-specific responses to IGR-based insecticides in a controlled environment, before broad-scale field applications that could result in suboptimal management of the target species.
Rowe, Cassandra, Wurster, Christopher M., Zwart, Costijn, Brand, Michael, Hutley, Lindsay B., Levchenko, Vladimir, and Bird, Michael I. (2021) Vegetation over the last glacial maximum at Girraween Lagoon, monsoonal northern Australia. Quaternary Research. (In Press)
Northern Australia is a region where limited information exists on environments at the Last Glacial Maximum (LGM). Girraween Lagoon is located on the central northern coast of Australia and is a site representative of regional tropical savanna woodlands. Girraween remained a perennial waterbody throughout the LGM, and as a result retains a complete proxy record of last glacial climate, vegetation and fire. This study combines independent palynological and geochemical analyses to demonstrate a dramatic reduction in tree cover, woody richness and expansion of grassland relative to current vegetation at the site. The process of tree decline was primarily controlled by the cool-dry glacial climate and CO2 effects, though more localised site characteristics restricted wetland associated vegetation. Fire processes played less of a role determining vegetation than in the Holocene and modern day, with reduced fire activity consistent with significantly lower biomass available to burn. This unique and detailed palaeoecological record provides the opportunity to explore and assess modelling studies of vegetation distribution during the LGM, particularly where a number of different global vegetation and/or climate simulations are inconsistent for northern Australia, and at a range of resolutions.
Rymer, Tasmin L., Cruise, Megan, and Pillay, Neville (2021) Decision-making by bushveld gerbils (Gerbilliscus leucogaster). Journal of Comparative Psychology. (In Press)
Decision-making reflects an individual’s behavioral motivation, shaped by intrinsic and extrinsic factors. We investigated the motivation and decision-making to forage in captive bushveld gerbils (Gerbilliscus leucogaster) using an individually tailored experimental protocol. Individual gerbils were subjected to 4 experiments, where we assessed behavior and decision-making in response to: (a) food quality when resources were clumped (Experiment 1), (b) food quality when resources were scattered (Experiment 2), (c) changing food distribution (clumped vs. scattered; Experiment 3), and (d) predation risk. Each experiment comprised 4 treatments, where both cost (a weighted door) and incentive (preferred vs. nonpreferred seeds; clumped vs. scattered seeds) varied according to the mass and personal preferences of individual gerbils. We counted the number of seeds eaten, assessed the frequency of door usage, and measured the duration of exploration, vigilance, and foraging (as a proportion of total time) of gerbils in each experiment. Gerbils showed individual preferences for different seed types although all preferred sunflower or sorghum seeds. Generally, gerbils ate more seeds and used the door more frequently when the costs were low. Similarly, gerbils tended to forage more when the costs were low and predation risk was low. We also found that males, in general, were more vigilant than females in Experiments 3 and 4, likely because of risk of intrasexual competition over a high-resource patch. There was considerable individual variation in behavior, but there was also consistency in most behaviors, indicating that individual gerbils perform consistently differently to other gerbils.
Gely, Claire, Laurance, Susan G. W., and Stork, Nigel E. (2021) The effect of drought on wood-boring in trees and saplings in a tropical forest. Forest Ecology and Management, 489. 119078.
Droughts are predicted to increase in severity in many regions due to climate change and there is strong evidence that such events can lead to increased insect attack and consequent widespread tree mortality in temperate forests. Much less is known about the impact of increased drought on tropical rainforests but in the few largescale drought manipulation experiments in tropical rainforests, larger trees had higher mortality rates than smaller trees although the cause of death is often uncertain. Previously, we modelled what the impact of drought might be on different types of herbivorous insects and suggested that in rainforests severe drought conditions might lead to increased attack from wood-boring insects. We tested this in a drought manipulation experiment, in Australian tropical rainforest, where we excluded more than 30% of rainfall for two years prior to our study and during it. We compared wood-boring damage of small and large trees between the experiment and a nearby control site. We hypothesized that larger trees would experience greater wood boring whereas smaller trees would present more surface damage. We surveyed 1,778 trees in total across both plots and found that the proportion of trees with termites, hole boring, and surface damage caused by borers (lateral tracks, frass, resin, latex or kino exudation) was significantly higher at the drought plot than at the control plot. There was a significant difference in the proportion of trees with fresh wood-boring damage at the drought site (35%) than at the control site (23%). While all size classes of trees had a higher percentage of fresh wood-boring damage at the drought site compared to control site this was only significant for small trees (dbh < 10 cm). The lack of significant difference for medium sized trees (dbh > 10 cm &<20 cm) and large trees (dbh > 20 cm) may be due to small sample size. Recent termite activity and termite damage was also significantly more frequent in the drought site compared to the control. We conclude that increased severity of drought appears to drive fundamental changes in borer and termite infestation levels with potentially important consequences for long-term tree health and mortality. Increases in tree mortality elevates the risk of forest fires, which are normally rare events in rainforests. Determining which wood boring beetles are responsible for the increased infestation requires further investigation since more than 100 wood-boring beetle species have been collected previously at the study site, including species of Platypodinae, Scolytinae, Anobiidae and Cerambycidae.
Orr, Ryan, Pattison, Anthony, Northfield, Tobin, and Nelson, Paul N. (2021) Iron chelates have little to no effect on the severity of Fusarium wilt of bananas in soils of the humid tropics. Journal of Plant Pathology, 103. pp. 595-604.
Previous research has shown that application of iron chelates to soil reduces Fusarium wilt in several crop species. The aim of this work was to test the effect for bananas grown in tropical soils. Disease severity and plant characteristics were measured in banana plants (cv. Ducasse, Musa ABB) grown in pots inoculated with Fusarium oxysporum f. sp. cubense, Race 1 in two experiments. Experiment 1 compared amendment with iron chelates (with ligands of differing iron binding stability) with water, plus an uninoculated unamended control, in two tropical Australian soils. Experiment 2 examined the effect of Fe-HBED application rate with high or low calcium addition. In Experiment 1, iron-saturated chelate application did not significantly affect disease severity or plant tissue iron concentration, irrespective of the iron binding stability of the chelate. In Experiment 2, disease severity was not affected by Fe-HBED or calcium application rate. The concentrations of iron and aluminium in plants were both somewhat affected by the addition of Fe-HBED, calcium and their interaction. Fusarium wilt of bananas was not affected by addition of iron chelates to these soils. The lack of effect was likely due to high iron availability in the soils overwhelming the capacity of the treatments to alter iron availability to the host plant and pathogen. Application of strong chelating ligands increased the concentration of aluminium and decreased the concentration of manganese in plant tissue, with possible detrimental effects.
Laurance, William F., Wich, Serge A., Onrizal, Onrizal, Fredriksson, Gabriella, Usher, Graham, Santika, Truly, Byler, Dirck, Mittermeier, Russell, Kormos, Rebecca, Williamson, Elizabeth A., and Meijaard, Erik (2020) Tapanuli orangutan endangered by Sumatran hydropower scheme. Nature Ecology and Evolution, 4 (11). pp. 1438-1439.
[Extract:] To the Editor — The Tapanuli orangutan survives today in less than 1,200 km2 of rainforest in northern Sumatra, Indonesia, in an area known as Batang Toru, where it was scientifically discovered1 in 1997. Teeming with endangered fauna and flora, the Batang Toru forest has been partially felled and fragmented and parts of the remainder allocated to agriculture, mining, hydropower and geothermal-energy production. The Tapanuli orangutan is estimated to number just 767 individuals, divided among three subpopulations1. Its total remaining habitat is merely a tenth of the size of Sydney, Australia.
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.
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