Essentialistic pluralism: the theory of spatio-temporal positioning of species using integrated taxonomy

The resurrection of essentialist arguments, in the context of the modern evolutionary synthesis, highlights the need for a break from historical definitions of ‘kind’ and ‘essence’ in order to bring a new paradigm in which these terms are used to conceptualise and understand evolutionary processes. The definition of ‘essence’ is herein divided into two distinct parts, namely the structural essence, which is mutable and has an evolutionary context; and the character essence, which is the immutable spatio-temporal expression of the structural essence of an individual. In contrast, the ‘kind’ is herein redefined as a region within a wider phylogenetically constrained organism state that reflects a conflux of character essences that form an immutable semaphoront. This organism state enables the hypothetical delineation of spatio-temporally immutable forms, called species, which are drawn from an evolutionary continuum. These revised definitions and the taxonomic clades derived from them determine the species that are used in the construction of phylogenies that reflect true historical and evolutionary relationships between organisms. The use of integrated taxonomy allows taxonomists to choose the appropriate concept enabling the evolutionary significance of the organism to be explained. This refocuses the argument from the concept back to the criteria, but often at the cost of causal explanation or conceptional explicitness. While integrated taxonomy allows the taxonomist the freedom to delineate species outside of any rigid conceptual framework, we seek to apply to this freedom a limit to the understanding of the evolutionary potential of an organism through the framing of that organism in a fixed spatio-temporal point. We call this confined potential the ‘essence matrix’, and it is these boundaries of this matrix that define the evolutionary potential of past and future forms, as well as define and restrict the field of morphospace upon which convergence and reticulation of taxa can occur. We name this limitation on evolutionary potential, the essentialist arguments used to construct it, and the integrated taxonomic approach to criteria selection, ‘essentialistic pluralism’. Finally, we will examine the complexity of species demarcation, noting the continuing failure for explicitness in conceptual application even if criteria are obvious

Desktop analysis to inform the design for megafauna monitoring within the Reef 2050 Integrated Monitoring and Reporting Program: final report of the seabirds team in the megafauna expert group

[Extract] The current seabird monitoring strategy for the Great Barrier Reef Marine Park is the Coastal Bird Monitoring and Information Strategy - Seabirds 2015-2050 (CBMIS-2015). This strategy is built around monitoring breeding populations of indicator species that represent different feeding guilds at identified essential breeding sites. Patterns of visitation aim to maximise the likelihood of surveys coinciding with the breeding of 20 species while minimising operational effort. Of necessity, the overall strategy is a compromise between the number of sites, visitation rates and logistic constraints. The Reef 2050 Integrated Monitoring and Reporting Program (RIMReP) review process undertaken here assesses whether the CBMIS-2015 strategy, designed within these constraints, is adequate to meet the needs of the Reef 2050 Long-Term Sustainability Plan (Reef 2050 Plan)

Ectomycorrhizal fungal communities are dominated by mammalian dispersed truffle-like taxa in north-east Australian woodlands

Mycorrhizal fungi are very diverse, including those that produce truffle-like fruiting bodies. Truffle-like fungi are hypogeous and sequestrate (produced below-ground, with an enclosed hymenophore) and rely on animal consumption, mainly by mammals, for spore dispersal. This dependence links mycophagous mammals to mycorrhizal diversity and, assuming truffle-like fungi are important components of mycorrhizal communities, to plant nutrient cycling and ecosystem health. These links are largely untested as currently little is known about mycorrhizal fungal community structure and its dependence on mycophagous mammals. We quantified the mycorrhizal fungal community in the north-east Australian woodland, including the portion interacting with ten species of mycophagous mammals. The study area is core habitat of an endangered fungal specialist marsupial, Bettongia tropica, and as such provides baseline data on mycorrhizal fungi-mammal interactions in an area with no known mammal declines. We examined the mycorrhizal fungi in root and soil samples via high-throughput sequencing and compared the observed taxa to those dispersed by mycophagous mammals at the same locations. We found that the dominant root-associating ectomycorrhizal fungal taxa (> 90% sequence abundance) included the truffle-like taxa Mesophellia, Hysterangium and Chondrogaster. These same taxa were also present in mycophagous mammalian diets, with Mesophellia often dominating. Altogether, 88% of truffle-like taxa from root samples were shared with the fungal specialist diet and 52% with diets from generalist mammals. Our data suggest that changes in mammal communities, particularly the loss of fungal specialists, could, over time, induce reductions to truffle-like fungal diversity, causing ectomycorrhizal fungal communities to shift with unknown impacts on plant and ecosystem health

Chapter 14: Vulnerability of seabirds on the Great Barrier Reef to climate change

Seabirds are highly visible, charismatic predators in marine ecosystems that are defined as feeding exclusively at sea, in either nearshore, offshore or pelagic waters. At a conservative estimate there are approximately 0.7 billion individuals of 309 species of seabirds globally. Such high population abundance means that in all ecosystems where seabirds occur the levels of marine resources they consume are significant. Such high consumption rates also mean that seabirds play a number of important functional roles in marine ecosystems, including the transfer of nutrients from offshore and pelagic areas to islands and reefs, seed dispersal and the distribution of organic matter into lower parts of the developing soil profile (eg burrow-nesting species such as shearwaters).This is Chapter 14 of Climate change and the Great Barrier Reef: a vulnerability assessment. The entire book can be found at http://hdl.handle.net/11017/13

Data on the fungal species consumed by mammal species in Australia

The data reported here support the manuscript Nuske et al. (2017). Searches were made for quantitative data on the occurrence of fungi within dietary studies of Australian mammal species. The original location reported in each study was used as the lowest grouping variable within the dataset. To standardise the data and compare dispersal events from populations of different mammal species that might overlap, data from locations were further pooled and averaged across sites if they occurred within 100 km of a random central point. Three locations in Australia contained data on several (>7) mycophagous mammals, all other locations had data on 1–3 mammal species. Within these three locations, the identity of the fungi species was compared between mammal species’ diets. A list of all fungi species found in Australian mammalian diets is also provide along with the original reference and fungal synonym names

Vegetative fragment production as a means of propagule dispersal for tropical seagrass meadows

Background and aims: Long distance dispersal (LDD) contributes to the replenishment and recovery of tropical seagrass habitats exposed to disturbance, such as cyclones and infrastructure development. However, our current knowledge regarding the physical attributes of seagrass fragments that influence LDD predominantly stems from temperate species and regions. The goal of this paper is to measure seagrass fragment density and viability in two tropical species, assessing various factors influencing their distribution. Methods: We measured the density and viability of floating seagrass fragments for two tropical seagrass species (Zostera muelleri and Halodule uninervis) in two coastal seagrass meadows in the central Great Barrier Reef World Heritage Area, Australia. We assessed the effect of wind speed, wind direction, seagrass growing/senescent season, seagrass meadow density, meadow location and dugong foraging intensity on fragment density. We also measured seagrass fragment structure and fragment viability; i.e., potential to establish into a new plant. Key results: We found that seagrass meadow density, season, wind direction and wind speed influenced total fragment density, while season and wind speed influenced the density of viable fragments. Dugong foraging intensity did not influence fragment density. Our results indicate that wave action from winds combined with high seagrass meadow density increases seagrass fragment creation, and that more fragments are produced during the growing than the senescent season. Seagrass fragments classified as viable for Z. muelleri and H. uninervis had significantly more shoots and leaves than non-viable fragments. We collected 0.63 (±0.08 SE) floating viable fragments 100 m−2 in the growing season, and 0.13 (±0.03 SE) viable fragments 100 m−2 in the senescent season. Over a third (38%) of all fragments collected were viable. Conclusion: There is likely to be a large number of viable seagrass fragments available for long distance dispersal. This study's outputs can inform dispersal and connectivity models that are used to direct seagrass ecosystem management and conservation strategies

Seabirds

[Extract]Seabirds are highly visible, charismatic predators in marine ecosystems that feed primarily or exclusively at sea. They have a range of relatively unique life-history characteristics associated with this marine lifestyle. Many of these characteristics are directly linked with having to forage over large distances to obtain sufficient food to breed

Seabirds

[Extract] Seabirds are highly visible, charismatic predators in marine ecosystems that feed primarily or exclusively at sea. They have a range of relatively unique life-history characteristics associated with this predominantly marine lifestyle. Many of these characteristics are directly linked with having to forage over large distances to obtain sufficient food to breed.\ud \ud In general, seabirds are long-lived species that have deferred sexual maturity, small clutch sizes, slow chick growth rates and extended fledgling periods. For example, crested terns may live 18-20 years, sooty terns up to 32 years and larger species such as boobies and frigate birds even longer. Most seabird species do not become sexually mature or return to breed for between 5 to 12 years after fledging and the nestling period for some species, such as frigate birds, can be up to six months long