The distribution of macroinvertebrates and fishes in Tasmanian estuaries

The distributions of 390 taxa of benthic macroinvertebrates collected in forty-eight estuaries and 101 fish species collected in seventy-five Tasmanian estuaries were related to geographical and environmental variables. Distribution patterns for the two taxonomic groups were largely congruent at both between and within-estuary scales. Faunal composition and the number of species collected at a site were primarily related to site salinity, the biomass of seagrass and tidal range. At the broader estuary scale, the distributions of macroinvertebrate and fish assemblages were primarily correlated with the presence of an entrance bar. Species richness varied with geographical location for both macrofauna and fishes, with highest numbers of species occurring in the Furneaux Group, north-eastern Tasmania and south-eastern Tasmania. These patterns primarily reflected differences in estuary type between regions rather than concentrations of locally endemic species. Although the majority of species collected during the study were marine vagrants, they constituted a very low proportion of total animal densities within estuaries. Only four species considered exotic to Tasmania were identifed. Nearly all species recorded from Tasmanian estuaries occurred widely within the state and have also been recorded in south-eastern Australia. Only 1% of estuarine fish species and < 5% of invertebrate species were considered endemic to the state. The generally wide ranges of species around Tasmania were complicated by (i) the absence of most species from the west coast (ii) a small (< 10%) component of species that occurred only in the north-east and Furneaux Group (eastern Bass Strait), and (iii) a few species (< 5%) restricted to other regions. The low number of species recorded from estuaries along the western Tasmanian coast reflected extremely low faunal biomass in that area. This depression in biomass on the west coast was attributed to unusually low concentrations of dissolved nutrients in rivers and dark tannin-stained waters which greatly restricted algal photosynthesis and primary production.     

Tasmanian rotifera: Affinities with the Australian fauna

Plankton was collected from more than 100 lentic and lotic habitats in Tasmania. Of the 131 rotifer taxa identified, 126 are first records for the island, and 9 are first records for Australia. Three new species, Aspelta tilba, sp. nov., Lepadella tyleri sp. nov., and Testudinella unicornuta sp. nov. are described and figured. Horaëlla brehmi, which has a disjunct distribution (equatorial regions and southeastern Australia), also occurs in Tasmanian waters. The morphology and development of this rare species are discussed. Geographical affinities of the Tasmanian assemblage are considered. There appears to be a significant tropical component in the Tasmanian Rotifera.     

Dynamics of a Tasmanian bolster heath string fen

The string fen at Newdegate Pass, Mt. Field, Tasmania consists of dams composed of bolster heath and peat derived from bolster heath, and flark ponds with concave sides and usually rocky floors. The bolster heath has a smooth surface which consists of a complex mosaic dominated byDonatia novae-zelandiae, Carpha rodwayi andDracophyllum minimum. The floors of the ponds usually support no macrophytes. The ponds situated on strong flow lines have shallower dams which are more often breached than those where flow is more diffuse. The ponds ultimately drain by tunnelling through the humified peat below the live roots of the bolster heath, and the exposed floors are colonized by bolster heath species. The underlying block stream has a topography partly independent from that of the string and flark features, which shift in both time and space.Species nomenclature follows Curtis (1963, 1967) and Curtis & Morris (1975) for gymnosperms and dicotyledons and Willis (1970) for monocotyledons except where authorities are given. Structural nomenclature follows Kirkpatrick (1983).     

Benthic macrofauna in Tasmanian estuaries: scales of distribution and relationships with environmental variables

Information on the distribution of species richness, faunal density, biomass and estimated productivity of benthic invertebrates in Tasmanian estuaries was quantified at a variety of spatial and temporal scales to assess general hypothesis relating community metrics to such environmental variables as salinity, seagrass biomass and sediment particle size. An associated aim was to assess appropriate scales of investigation for soft-sediment biota distributed in estuaries, including whether patterns identified at individual sites, estuaries, tidal levels or times are likely to have more general relevance. Faunal biomass and productivity varied principally at between-estuary (10 to 1000 km) and replicate-sample (1 m) scales, indicating that these two community metrics were largely responding to estuary-wide effects, such as nutrient loading, and to microhabitat features, rather than to locality characteristics at intermediate scales such as salinity, anoxia or sediment particle size. By contrast, faunal density showed greater response to tidal height (1 to 100 m) and to factors distributed at the locality scale within estuary (10 km) than to factors between estuary. Both faunal density and species richness in estuaries declined over three- and fivefold ranges down the shore from high water mark to the shallow sublittoral, while estimated productivity and biomass showed highest overall levels at low water mark. The greatest component of variance in species richness was associated with tidal height, with variance then distributed approximately evenly between other spatial scales examined. At the low-tide and shallow subtidal levels, species richness, faunal biomass and estimated productivity were all highly correlated with salinity and biomass of macrophytes, whereas faunal density was highly correlated with biomass of macrophytes only. Relationships between environmental and biological variables examined were poorly defined at high tidal levels. Seasonal plus interannual variance was much lower than spatial variance—a clear indication that sampling effort in studies would generally be better directed across a range of localities than for a single locality to be repeatedly investigated over time.     

Towards an explanation of the causes of the rarity of two Tasmanian Spyridium species

Spyridium microphyllum (F. Muell. ex Reissek) Druce and Spyridium obcordatum (Hook. f) W. M. Curtis are narrow endemic shrubs which are confined to small parts of Tasmania, Australia, and are rare within their present ranges. Analysis of quadrat data from transects through populations of both species showed that at most individual sites the rare taxa occur in floristically and environmentally distinct situations. However, sites supporting the same species differ floristically and environmentally, with the only communality being a lack of dense tall shrub or tree cover. Both species are absent from many areas with closely similar physical environments and vascular plant species composition to those in which they occur. Thus, their current distributions cannot be explained by limitation to a rare habitat. Spyridium microphyllum appears to be susceptible to local extinction because it is an obligate seeder, is killed by fire, does not survive in taller, dense vegetation, and is not adapted for dispersal over the distances between its potential habitats. While S. obcordatum recovers vegetatively after fire, it also does not survive in dense taller vegetation, has limited dispersal ability and highly disjunct potential habitat. Both species may have been more widespread and competitive during cooler and drier times.     

Understanding variation in human fertility: what can we learn from evolutionary demography?

Decades of research on human fertility has presented a clear picture of how fertility varies, including its dramatic decline over the last two centuries in most parts of the world. Why fertility varies, both between and within populations, is not nearly so well understood. Fertility is a complex phenomenon, partly physiologically and partly behaviourally determined, thus an interdisciplinary approach is required to understand it. Evolutionary demographers have focused on human fertility since the 1980s. The first wave of evolutionary demographic research made major theoretical and empirical advances, investigating variation in fertility primarily in terms of fitness maximization. Research focused particularly on variation within high-fertility populations and small-scale subsistence societies and also yielded a number of hypotheses for why fitness maximization seems to break down as fertility declines during the demographic transition. A second wave of evolutionary demography research on fertility is now underway, paying much more attention to the cultural and psychological mechanisms underpinning fertility. It is also engaging with the complex, multi-causal nature of fertility variation, and with understanding fertility in complex modern and transitioning societies. Here, we summarize the history of evolutionary demographic work on human fertility, describe the current state of the field, and suggest future directions.     

Hickmania Troglodytes, the Tasmanian Cave Spider, and its Potential Role in Cave Management

Cave faunas – which often contain a high representation of spiders – are subject to increasing pressure from the effects of epigean habitat degradation and recreational caving activities. Hickmania troglodytes is a prominent member of the Tasmanian cave fauna, a spider of phylogenetic, zoogeographic and ecological importance, but about which little has previously been known. Long-term monitoring has revealed many unusual life-cycle characteristics in this species, most of which occur over long periods of time and are dependent upon environmental stability. The species presents a potentially useful tool in the management and monitoring of cave fauna and karst, as it is large, conspicuous, numerous, ubiquitous, sedentary, functionally significant and potentially sensitive to various sources of disturbance. H. troglodytes may provide a visible and obvious measure of disturbance in and around cave entrances, and may also prove useful in detecting broader scale impacts affecting the entire cave. Many promising developments are being made in terms of cave management in Tasmania, but other issues are less well addressed and still need to be resolved. With further research, the use of indicator or sentinel species may prove to be well suited to the less complex and often sparsely populated subterranean environment, and may play an important role within larger management strategies for cave fauna and karst.     

Biometric relationships between body and otolith measurements in nine demersal fishes from north‐eastern Tasmanian waters,Australia

Relationships between fish and otolith measurements were analyzed in nine demersal fishes from the north‐eastern Tasmanian waters: Foetorepus calauropomus, Trachurus declivis, Parequula melbournensis, Neosebastes scorpaenoides, Platycephalus aurimaculatus, Platycephalus bassensis, Platycephalus conatus, Lepidotrigla mulhalli and Lepidotrigla vanessa. The values of exponent b from the relationships between fish weight and fish total length, total length and otolith length, total length and otolith width, and fish weight and otolith length were estimated. All above relationships were statistically significant. The analysis of covariance (ANCOVA) was used to test the effect of the categorical factor of species in the fish length and otolith length relationship. Significant differences in fish length and otolith length relationship between species were highlighted in both gurnards and flatheads. Results from this study will provide novel information on quantitative biometric relationships between body and otolith measurements of fish species in Australian waters.     

The Tsimane Health and Life History Project: Integrating anthropology and biomedicine

The Tsimane Health and Life History Project, an integrated bio‐behavioral study of the human life course, is designed to test competing hypotheses of human life‐history evolution. One aim is to understand the bidirectional connections between life history and social behavior in a high‐fertility, kin‐based context lacking amenities of modern urban life (e.g. sanitation, banks, electricity). Another aim is to understand how a high pathogen burden influences health and well‐being during development and adulthood. A third aim addresses how modernization shapes human life histories and sociality. Here we outline the project's goals, history, and main findings since its inception in 2002. We reflect on the implications of current findings and highlight the need for more coordinated ethnographic and biomedical study of contemporary nonindustrial populations to address broad questions that can situate evolutionary anthropology in a key position within the social and life sciences.     

Tasmanian lentic wetland lawns are maintained by grazing rather than inundation

Vertebrate grazers have been shown to be a critical element in maintaining lawns, although lawns can also form in places without such herbivores. In Tasmania lawns are widespread in lentic wetlands. We used environmental observations and exclosure experiments at two altitudinally contrasting lentic wetland lawns, and waterlogging experiments, to test the hypotheses that their structure is maintained (i) periodic inundation; and (ii) grazing. Waterlogging experiments and field observations demonstrated that the two main invading shrubs were indifferent to immersion for several months and that the distribution of the lawns was independent of inundation period, results inconsistent with the first hypothesis. The exclosure experiments showed that both woody and non‐woody plants became taller in the lawns when marsupial grazers and rabbits were excluded. It therefore seems that the lawn structure is maintained by grazing and that alternative structural states result from exclusion of grazing pressure in less than 2 years.     

Impacts of hive honeybees on Tasmanian leatherwood Eucryphia lucida Labill. (Eucryphiaceae)

Despite honeybees (Apis mellifera L.) occurring as a feral and commercially managed species in many parts of Australia, the effects of honeybees on native Australian ecosystems are poorly understood. We examined the impacts of honeybee apiaries on Tasmanian Leatherwood Eucryphia lucida Labill. (Eucryphiaceae) by comparing commercial apiary sites with control sites >2 km from the nearest apiary. Feral honeybees were common at control sites (73% of honeybees feral) but were scarce at apiary sites (2%), and hive honeybees appeared to be competitively displacing feral honeybees near apiaries. Visit rates by native insects appeared to be un‐affected by the increased numbers of hive honeybees near apiaries. Standing crops of nectar sugar were significantly depressed at apiary sites. Pollen was rapidly removed from flowers at apiary sites resulting in full separation of the male and female flower‐phases (flowers completely dichogamous). In contrast, at control sites, pollen tended to remain in flowers into the female phase (flowers partially dichogamous). There was no difference in the total number of pollen grains deposited on stigmas or in percentage seed set among apiary and control sites. However, fruit set was elevated at apiary sites, possibly owing to reduced autonomous (within‐flower) selfing. Our study indicated that honeybees significantly reduce floral resources (nectar and pollen) around apiaries, although any competitive effects on native insects may have been obscured by large variation in the abundance of native insects among experimental sites.     

Investigating the potential for Southern Hemisphere climate reconstruction using stable isotopes in Tasmanian tree rings

Few annually dated stable isotope records exist across Oceania. Stable carbon and oxygen isotope ratios have the potential to enhance climate reconstructions currently reliant on tree ring width chronologies. The purpose of this study is to explore the sources of variability in a stable oxygen isotope chronology derived from A. selaginoides from Mount Read, Tasmania. This high elevation site receives abundant rainfall throughout the year and is ∼130 km from the Global Network of Isotopes in Precipitation (GNIP) site at Cape Grim. We crossdated 10 new tree core samples against an existing ring width chronology (954–2011 CE) and analyzed the δ¹⁸O from the individual rings for the period 1960–2018. Using high resolution (0.25 degrees) climate data and ECMWF ERA5 reanalysis data, we disentangled the effects of local climate and source region on the isotopic signatures recorded in the annual rings. In addition, we used HYSPLIT backward trajectory analysis to characterize the source region of precipitation to Mount Read and whether the source region has influence over the δ¹⁸O_TR series. Median δ¹⁸O_TR (n = 10) is correlated with local temperature and vapor pressure deficit in the early growing season. In addition, spatial correlations reveal that median δ¹⁸O_TR is positively correlated with temperature and negatively correlated with precipitation in the source region. However, measurements of δ¹⁸O_TR exhibit high inter-tree variation, particularly between 1960 and 1990. Our results indicate that this δ¹⁸O_TR proxy may provide additional information about past moisture conditions during the growing season, potentially contributing to more robust reconstructions of the Southern Hemisphere climate dynamics; however, additional sampling may be necessary to resolve inter-tree variation in δ¹⁸O_TR.     

Response of a southern temperate marsupial, the Tasmanian pademelon (Thylogale billardierii), to historical and contemporary forest fragmentation

Despite only limited Pleistocene glacial activity in the southern hemisphere, temperate forest species experienced complex distributional changes resulting from the combined effects of glaciation, sea level change and increased aridity. The effects of these historical processes on population genetic structure are now overlain by the effects of contemporary habitat modification. In this study, 10 microsatellites and 629 bp of the mitochondrial control region were used to assess the effects of historical forest fragmentation and recent anthropogenic habitat change on the broad-scale population genetic structuring of a southern temperate marsupial, the Tasmanian pademelon. A total of 200 individuals were sampled from seven sites across Tasmania and two islands in Bass Strait. High mitochondrial and nuclear genetic diversity indicated the maintenance of large historical population sizes. There was weak phylogeographical structuring of haplotypes, although all King Island haplotypes and three Tasmanian haplotypes formed a divergent clade implying the mid-Pleistocene isolation of a far northwestern population. Both the mitochondrial and nuclear data indicated a division of Tasmanian populations into eastern and western regions. This was consistent with a historical barrier resulting from increased aridity in the lowland 'midlands' region during glacial periods, and with a contemporary barrier resulting from recent habitat modification in that region. In Tasmania, gene flow appears to have been relatively unrestricted during glacial maxima in the west, while in the east there was evidence for historical expansion from at least one large glacial refuge and recolonization of Flinders Island.     

Technique for washing nectar from the flowers of Tasmanian leatherwood (Eucryphia lucida Eucryphiaceae)

The technique for extracting floral nectar using micropipettes is often unsuited to flowers where nectar is produced in very small volumes and/or where nectar is highly viscous. An alternative technique for washing the viscous nectar from the flowers of Tasmanian leatherwood, Eucryphia lucida (Labill.) is described. Here, two washes with a known volume of distilled water removed 95% of total floral sugar. Using such a washing technique on exposed and bagged E. lucida flowers provided information on nectar production in this species that could not have been obtained using a standard micropipette extraction method.     

A history of physical anthropology and the development of evolutionary thought in Canada

Canada is a large country geographically, but relatively small in terms of population. As a result, our major problem has always been communication. It is expensive and time consuming to get together to discuss problems. For example, a scholar in Newfoundland would find Prague to be as far away as a visit to a university in her own country (British Columbia). Then too, communication is often confounded by language because we are a bilingual country, but relatively few people speak both languages. Understandably, then, it is very difficult to speak of a national identity on such a topic as human evolution. Rather, we find that individuals have influenced the field either through their research or through their teaching. Academic development has been strongly influenced in the past by developments in the United States and Europe, particularly the United Kingdom. Nevertheless, we will attempt to trace the development of evolutionary throught, but not without a preliminary apology for oversights to our colleagues. The task is difficult, and we will surely overlook some names. We hope that our attempt will still be accurate in the wholistic sense. Regardless of the foregoing problems, we do see a broad historical development and the beginning of a Canadian perspective. This is more clearly seen if we trace the development of evolutionary thought within the context of the history of physical anthropology in Canada.     

Morphology and taxonomy of Cyclotella tasmanica spec. nov,a newly described diatom from Tasmanian lakes

A species of Cyclotella with an elliptical valve outline has been found in several Tasmanian lakes and is herein described and named C. tasmanica nov. sp. Morphologically, it is similar to C. stelligera and, to a lesser extent, to C. radiosa. The valve has coarse, clearly alveolate, marginal striae and a central rosette. Unlike other elliptical forms, the central area is always more or less circular. The nearest similar species is C. rhomboideo-elliptica.     

Biomechanics in anthropology

Biomechanics is the set of tools that explain organismal movement and mechanical behavior and links the organism to the physicality of the world. As such, biomechanics can relate behaviors and culture to the physicality of the organism. Scale is critical to biomechanical analyses, as the constitutive equations that matter differ depending on the scale of the question. Within anthropology, biomechanics has had a wide range of applications, from understanding how we and other primates evolved to understanding the effects of technologies, such as the atlatl, and the relationship between identity, society, culture, and medical interventions, such as prosthetics. Like any other model, there is great utility in biomechanical models, but models should be used primarily for hypothesis testing and not data generation except in the rare case where models can be robustly validated. The application of biomechanics within anthropology has been extensive, and holds great potential for the future.