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The effects of grazing and browsing by terrestrial vertebrates are poorly understood for southern hemisphere saltmarshes, many of which are recovering from stock grazing. We investigated whether the native late-successional shrub, Tecticornia arbuscula, regenerating several years after the cessation of stock grazing, was grazed by wild herbivorous mammals to the degree of impeding recovery. We measured T. arbuscula growth parameters in exclosures and adjacent controls for two years and used camera trapping of animals across four consecutive austral seasons to indicate grazing pressure. Height growth was more affected by exclosure from grazing than lateral change. Notably, grazing did not prevent the recovery of the shrubs from stock grazing at either site, suggesting that the growth rate of T. arbuscula relative to total grazing pressure is at sustainable levels and these shrubs are in a trajectory of recovery, with the smaller plants growing the fastest. Also, we found little difference between our two sites in grazing impact, despite one site having twice the number of animals, largely native macropods, as the other site, which was dominated by introduced lagomorphs (rabbits and hares). These findings further the knowledge of native and non-native terrestrial vertebrates in austral saltmarsh ecology and conservation. [ABSTRACT FROM AUTHOR]

Fish use of saltmarsh varies spatially, temporally, and with environmental conditions. The specific impact of these effects on fish assemblages in southern temperate Tasmania, Australia—the only mangrove-free Australian state—is as yet largely unknown. Seasonal variation in fish abundance, richness, diversity, and size was investigated in succulent saltmarshes in three estuaries (Marion Bay, Barilla Bay, and Ralphs Bay) in south-eastern Tasmania. All parameters varied between sampling locations. Greater numbers of fish were recorded at two sites (Marion Bay, mean density and standard error of 396.9 ± 71.3 individuals per 100 m2; Barilla Bay, mean density and standard error of 94.1 ± 30.1 individuals per 100 m2) than have been previously reported in Australian saltmarshes. Fish abundance was greatest in July–August (mean density and standard error of 200.2 ± 49.7 individuals per 100 m2) reflecting the breeding patterns of the numerically dominant Atherinosoma microstoma. Both abundance and species richness responded positively to water temperature in ordinal logistic regression models, and species richness and diversity increased with water depth in the models. It is likely that the strong differences between sampling locations are partly related to differences in water depth and water temperature between the estuaries. They may be also related to the habitat context of each estuary, especially the presence or absence of seagrass. The greater numbers of fish found in the present study relative to abundances reported in mainland Australia may relate to the absence of mangroves and the consequent differences in seascape habitat context, including greater water depths in marshes. Importantly, these results demonstrate that temperate southern hemisphere saltmarshes are year-round habitat for fish, thus emphasising their importance as a fish habitat. [ABSTRACT FROM AUTHOR]

Deciding whether to plant native or non-native trees in public urban green spaces is becoming complex and conflicted, and decisions purely based on biotic nativeness are likely to be hamstrung as climate change and rising urban heat push many native species beyond their natural ranges. Importantly, tree selection considerations by urban planners and environmental managers will have to move beyond a primary focus on securing conservation and ecological outcomes, to elucidate and engage with a growing interest in the socio-cultural values and services of urban trees. Building on emerging theoretical perspectives, this place-based study explores the role that perceptions of nativeness have in shaping people's relationships with native and non-native urban trees and landscapes in an Australian city. Nativeness was associated with a range of subjective meanings including cultural identity, political expression, nature connection, desirable and undesirable traits, and environmental and cultural compatibility. Our findings emphasise that the ways in which urban trees and green spaces are valued and experienced is likely mediated by people's perceptions of nativeness and its importance relative to other attributes. To provision and sustain green spaces that meet the diverse needs and preferences of urban publics, planners and managers need to elucidate and incorporate the nuanced, place-based and multifaceted subjective meanings of nativeness into urban greening decision-making and practice. [ABSTRACT FROM AUTHOR]

Total organic carbon (TOC) sediment stocks as a CO2 mitigation service require exclusion of allochthonous black (BC) and particulate inorganic carbon corrected for water–atmospheric equilibrium (PICeq). For the first time, we address this bias for a temperate salt marsh and a coastal tropical seagrass in BC hotspots that represent two different blue carbon ecosystems of Malaysia and Australia. Seagrass TOC stocks were similar to the salt marshes with soil depths < 1 m (59.3 ± 11.3 and 74.9 ± 18.9 MgC ha− 1, CI 95 % respectively). Both ecosystems showed larger BC constraints than did their pristine counterparts. However, the seagrass meadows’ mitigation services were largely constrained by both higher BC/TOC and PICeq/TOC fractions (38.0 % ± 6.6 and 43.4 % ± 5.9 %, CI 95 %) and salt marshes around a third (22 % ± 10.2 and 6.0 % ± 3.1 % CI 95 %). The results provide useful data from underrepresented regions, and, reiterates the need to consider both BC and PIC for more reliable blue carbon mitigation assessments to ensure that greenhouse gas emitters do not exceed the ecosystems’ capacity. [ABSTRACT FROM AUTHOR]

Rising sea levels and changing wind climates are widely expected to be associated with receding coastlines, creating a planning need for coastal change prediction, especially for soft shores like those associated with saltmarsh. We ask whether it is possible use a simple cartographic wind-wave fetch method to estimate the spatial pattern of progradation and recession of soft shores in swell-sheltered situations in which there is little or no input of new sediment from terrestrial sources. For points on an extensive embayment shoreline of this type we mapped change over 54 years from aerial photographs, recorded current shoreline morphology and calculated a wave fetch index (WFI). Morphological indication of strong progradation was associated with low WFI, but there was no statistically significant effect of variation in WFI on the degree of shoreline retreat. Saltmarsh shorelines averaged 14 cm per annum retreat between 1952 and 2006, a rate that did not vary significantly between air photo periods. We conclude that our geographic information system approach utilising WFI is likely to be useful as a planning tool in identifying those parts of sediment-poor saltmarsh shores where erosion is most likely or least likely to occur, but not particularly useful for predicting finer-scale variation in rates of shoreline recession within the particular substrate types in our study area. In the context of relative sea-level rise and increasing wind speeds, such modelling can help identify coastlines which are likely to support saltmarshes into the future. [ABSTRACT FROM AUTHOR]