Vertebrates are poor umbrellas for invertebrates: cross-taxon congruence in an Australian tropical savanna

Invertebrates are commonly ignored in conservation planning due to their vast diversity, difficulties with species identification, a poor understanding of their spatial patterns, and the impracticability of carrying out comprehensive sampling. Conservation planning for fauna is therefore often based on patterns of diversity and distribution of vertebrates, under the assumption that these are representative of animal diversity more generally. Here, we evaluate how well vertebrates act as umbrellas for invertebrate diversity and distribution in a highly diverse tropical savanna landscape, and we investigate the effect of vertebrate sampling intensity (i.e., number of surveys) on congruence results. We assessed congruence between each of the four classes of terrestrial vertebrates (amphibians, reptiles, birds, and mammals) and twelve invertebrate families (representing four dominant invertebrate taxa: ants, beetles, flies, and spiders) by applying a range of modeling approaches to analyze patterns of cross‐taxon congruence in species richness and composition across sampling sites. To investigate drivers of congruence, we applied generalized and distance‐based linear models to identify environmental associations of richness and composition for each taxon, then examined variation in environmental associations across taxa. Vertebrate and invertebrate richness was weakly (<30%) associated, and ~60% of the significant associations were negative. Correlations in species composition between vertebrate and invertebrate taxa were also weak, with a maximum of 13% congruence. In most cases, pairwise correlation scores using data from single surveys of vertebrates were only marginally lower than those from multiple surveys. Poor among‐site congruence between vertebrates and invertebrates was reflected by marked variation among taxa in their environmental associations. Our findings show that vertebrates are poor umbrellas for invertebrates in the tropical savannas of northern Australia in terms of geographic patterns of diversity and distribution and that this is not just an artifact of low vertebrate sampling intensity. Our study is one of the most comprehensive regional analyses of the congruence of vertebrate and invertebrate diversity, and it significantly adds to the growing evidence that empirical data on invertebrate diversity and distribution are required for conservation planning that effectively protects all faunal diversity

Convergence of marine megafauna movement patterns in coastal and open oceans

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 115 (2018): 3072-3077, doi:10.1073/pnas.1716137115.The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyse a global dataset of 2.8 million locations from > 2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared to more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal micro-habitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise and declining oxygen content.Workshops funding granted by the UWA Oceans Institute, AIMS, and KAUST. AMMS was supported by an ARC Grant DE170100841 and an IOMRC (UWA, AIMS, CSIRO) fellowship; JPR by MEDC (FPU program, Spain); DWS by UK NERC and Save Our Seas Foundation; NQ by FCT (Portugal); MMCM by a CAPES fellowship (Ministry of Education)

Shearwater Foraging in the Southern Ocean: The Roles of Prey Availability and Winds

Background Sooty (Puffinus griseus) and short-tailed (P. tenuirostris) shearwaters are abundant seabirds that range widely across global oceans. Understanding the foraging ecology of these species in the Southern Ocean is important for monitoring and ecosystem conservation and management. Methodology/Principal Findings Tracking data from sooty and short-tailed shearwaters from three regions of New Zealand and Australia were combined with at-sea observations of shearwaters in the Southern Ocean, physical oceanography, near-surface copepod distributions, pelagic trawl data, and synoptic near-surface winds. Shearwaters from all three regions foraged in the Polar Front zone, and showed particular overlap in the region around 140°E. Short-tailed shearwaters from South Australia also foraged in Antarctic waters south of the Polar Front. The spatial distribution of shearwater foraging effort in the Polar Front zone was matched by patterns in large-scale upwelling, primary production, and abundances of copepods and myctophid fish. Oceanic winds were found to be broad determinants of foraging distribution, and of the flight paths taken by the birds on long foraging trips to Antarctic waters. Conclusions/Significance The shearwaters displayed foraging site fidelity and overlap of foraging habitat between species and populations that may enhance their utility as indicators of Southern Ocean ecosystems. The results highlight the importance of upwellings due to interactions of the Antarctic Circumpolar Current with large-scale bottom topography, and the corresponding localised increases in the productivity of the Polar Front ecosystem

Global tracking of marine megafauna space use reveals how to achieve conservation targets

The recent Kunming-Montreal Global Biodiversity Framework (GBF) sets ambitious goals but no clear pathway for how zero loss of important biodiversity areas and halting human-induced extinction of threatened species will be achieved. We assembled a multi-taxa tracking dataset (11 million geopositions from 15,845 tracked individuals across 121 species) to provide a global assessment of space use of highly mobile marine megafauna, showing that 63% of the area that they cover is used 80% of the time as important migratory corridors or residence areas. The GBF 30% threshold (Target 3) will be insufficient for marine megafauna’s effective conservation, leaving important areas exposed to major anthropogenic threats. Coupling area protection with mitigation strategies (e.g., fishing regulation, wildlife-traffic separation) will be essential to reach international goals and conserve biodiversity.</p

Global tracking of marine megafauna space use reveals how to achieve conservation targets

The recent Kunming-Montreal Global Biodiversity Framework (GBF) sets ambitious goals but no clear pathway for how zero loss of important biodiversity areas and halting human-induced extinction of threatened species will be achieved. We assembled a multi-taxa tracking dataset (11 million geopositions from 15,845 tracked individuals across 121 species) to provide a global assessment of space use of highly mobile marine megafauna, showing that 63% of the area that they cover is used 80% of the time as important migratory corridors or residence areas. The GBF 30% threshold (Target 3) will be insufficient for marine megafauna’s effective conservation, leaving important areas exposed to major anthropogenic threats. Coupling area protection with mitigation strategies (e.g., fishing regulation, wildlife-traffic separation) will be essential to reach international goals and conserve biodiversity

A review of the use of seabirds as indicators in fisheries and ecosystem management

L.D. Einode

The foraging ecology of the short-tailed shearwater puffinus tenuirostris.

The short-tailed shearwater Puffinus tenuirostris is one of the world’s most abundant seabirds, with a population of around 23 million breeding birds. Despite this abundance we have a limited understanding of their role in the marine ecosystem. This is largely due to the many uncertainties surrounding the trophic interactions, resource requirements and foraging ecology of this wide ranging pelagic seabird. I studied the movement of adults during the short trip (ST) and long trip (LT) component of their dual foraging strategy to determine how they use their marine habitat. ST were primarily confined to neritic (continental shelf) waters 30 to 100 km from their colony, and maximum depth gauges revealed that birds reached a depth of 21 ± 13 m (SD). Analysis of the time spent in area by 39 individuals performing ST revealed that 18 birds employed area restricted searches within circles of a diameter of 14 ± 3 km (SE). Prey returns from area restricted search flights were predominated by bony fish, whereas prey diversity increased for non-area restricted search flights, with more krill and cephalopods. Thus, direct flights were performed when birds were exploiting prey patches dominated by fish, in contrast to the more varied diet returned when birds covered greater distances. LT flights were highly variable ranging from 11 - 32 days duration, and reaching 912 – 6,952 km from the colony. Foraging trips of extended duration enabled birds to exploit temperate waters further away from the colony, as well as sub Antarctic and Antarctic waters. A wider range of search patterns were performed on LT, as birds either: (1) showed no signs of area restricted search; (2) concentrated area restricted search directly at small scales of within circles of 33 ± 11 km (SE) diameter; or, (3) adopted a hierarchical mode of foraging, where large scales of area restricted search are first performed, followed by nested searches at smaller scales. This variation in foraging behaviour indicates that a range of foraging tactics are employed by the short-tailed shearwater. LT to sub Antarctic and Antarctic waters commonly involved a period of commuting travel to regions with elevated chlorophyll a associated with ocean fronts, where search effort was increased. How adults allocated time and energy during the entire chick-rearing period was investigated via the simultaneous assessment of adult attendance, adult mass change, the rate of energy delivery to chicks, and chick survival. Adults who reared chicks to good condition spent 80 % of the 90 day chick rearing period performing five - six LT of 13 ± 3 days (SE) duration. The remaining 20 % of time involved 14 ± 3 ST (SE) of one to three days duration. Comparison with chicks of moderate and poor condition revealed that, despite extensive variation in the day to day rate of provisioning, a small change in the proportion of time spent performing ST and LT over the entire chick rearing period can spell the difference between breeding success and failure. By allocating all of the food collected on ST to chicks birds depleted stored energy reserves, which were replenished on LT. Of the total energy required by chicks from hatching to adult abandonment 75 % was delivered from LT in the form of energy rich stomach oil, with the remainder being supplied in ST meals of raw prey. The advantages of the dual foraging strategy to both adult and chick was demonstrated by considering the daily food requirements of chicks and the likely energy flow from alternate feeding regimes. Under regimes of all ST or all LT, energy flow to chicks could not meet chick energy requirements. This highlights that LT of more than seven days duration are required to accumulate stomach oil. Oil boosts the energy value of meals beyond that achievable in continuous ST foraging. Under continuous ST the estimated rate of food consumption achieved by adults would not sustain both adult and chick requirements. Therefore the dual strategy enables short-tailed shearwaters to overcome many of the constraints of central-place foraging. Comparisons between years and short-tailed shearwater colonies revealed extensive variation in the dietary composition of meals returned to chicks, as well as the rate of food delivery. A year of increased ST foraging resulted in an increase in feeding frequency, but not provisioning rate, as smaller meals were returned. In this same year ST meals also contained a high % mass of low energy neritic prey (Australian krill Nyctiphanes australis and cephalopods). These factors reduced the rate of energy flow to chicks compared to other years where fewer ST meals of increased mass contained mostly higher energy fish (jack mackerel Trachurus declivis and anchovy Engraulis australis). While the rate of chick growth at different ages varied between years, a similar peak mass was gained in all three years. These findings demonstrate considerable flexibility in the dual foraging strategy of the short-tailed shearwater, providing evidence that adults are able to maintain a suitable rate of energy flow to chicks in years of varied neritic foraging conditions. This is achieved by modifying the time spent performing ST, and the volume of oil returned from LT, likely in response to changing prey availability. A review of the use of seabirds in fisheries management identified the most commonly used indicators (species and parameters) in environmental, ecological and fisheries management. For the short-tailed shearwater the most useful parameters for identifying the size of pelagic fish stocks in neritic waters include the size and dietary composition of meals returned on ST. The varied importance of pilchard Sardinops sagax and anchovy Engraulis australis in the diet between years suggest that their occurrence in the diet meals present a potential indicator of the availability of pre-recruits into the South Australian pilchard fishery. The occurrence of Australian Krill in ST meals may also provide a means of investigating the ecological role of upwelling events in neritic waters. The usefulness of provisioning parameters as indicators of prey availability are likely to be limited in this species, due to the extent of flexibility and plasticity in the short-tailed shearwaters provisioning strategy. Documenting the extent of flexibility in the foraging strategy, and quantifying the value of the ST and LT component of the dual foraging strategy has provided an insight into the habitat utilisation and prey requirements of this species. This demonstrates that despite the various constraints incurred in sourcing and transporting prey over long distances, dual foraging presents the most optimal foraging strategy for the delivery of energy to adult and chick. The sheer abundance of this species is evidence that the separation of their foraging and breeding grounds over 3000 km is a beneficial strategy. An opportunistic diet, and flexibility in foraging suggests that the short-tailed shearwater is more resilient to changes in prey availability than other seabirds in their community. However, we have highlighted that breeding success is sensitive to small changes in the time spent foraging in near and distant waters. Sourcing prey over large spatial scales also exposes birds to feeding conditions over a broader area, increasing their exposure to the potential effects of current and future climate change. For these reasons the short-tailed shearwater presents a valuable indicator species for short and long-term monitoring programs of both neritic and oceanic ecosystems.Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2010

Aspects of the Hindlimb Morphology of Some Australian Birds of Prey: A Comparative and Quantitative Study

Abstract We quantified the extent of adaptive radiation in the evolution of the hindlimb in the bird-of-prey community on Tasmania. Assessments of the ecological capabilities of raptor species are often based on a visual inspection of their hindlimb structure, with little recourse to direct biomechanical or functional evidence. We examined the links between hindlimb structure and patterns of diet, foraging, and habitat use in raptors by analytically investigating tarsus, toe, and talon measurements. We identified groupings on the basis of dietary preference, hunting-killing technique, and phylogeny. We found that the bird-catching specialists, which possessed relatively long digits with short talons, were consistently separable. The large-mammal and fish specialists were equipped with relatively short and robust tarsi, and short digits with long and robust talons. The hindlimbs of medium-mammal specialists were characterized by long digits and a large digit 1 talon. However, the generalist group did not possess any specializations, because their structural elements were comparable to those of other dietary groups. An association was found between the ratio of toe to talon length and the selective pressures of prey capture and ease of killing. Morphological variation in this feature was consistent with phylogeny, because the Accipitridae were characterized by a larger ratio of toe to talon length on digits 1 and 2 than the Falconidae, and the diurnal raptors possessed an interdigital pattern of larger variation in ratio of toe to talon length than the nocturnal raptors. No link was found between dietary habit and tarsus length or robustness, because these features were apparently attributed to variations in hunting style. Our analysis highlights the interrelationship between the morphology of hindlimb structure and the functional pressures associated with predatory lifestyles. Aspects de la morphologie des membres postérieurs de quelques oiseaux de proie australiens : Une étude comparative et quantitative</jats:p

Understanding habitat use of the Endangered Alligator Rivers Yellow Chat <i>Epthianura crocea tunneyi</i> to inform monitoring and management

Summary Knowledge of where a threatened species occurs in a landscape is crucial for determining its habitat requirements and informing its conservation planning and management. We conducted the first broad-scale survey of the Endangered Alligator Rivers Yellow Chat Epthianura crocea tunneyi across much of its known range on drying coastal floodplains in northern Australia. Presence-absence records from 257 sites surveyed in the late dry season (August–December) of 2018 and 2019 were modelled using occupancy/detectability models. Occupancy was estimated to be 0.10 ± 0.04 with a high detection probability (0.89 ± 0.07). Modelling of 13 site-level environmental covariates found that chats were more likely to be detected at sites where the native shrub Sesbania sesban was present, were close to hydrogeological features such as depressions or channels, were long unburnt (5+ years) and/or with topsoil damage caused by feral pigs. Our estimates of chat occupancy, detectability, and the covariates that influence their occupancy, have improved our understanding of the role that fire and feral animals have on chat distribution and habitat selection, and can be used as a baseline for future monitoring. We also provide recommendations on how to design and implement future monitoring of this subspecies.</jats:p