The Okubo–Weiss–Zeta (OWZ) tropical cyclone (TC) detection scheme, which has been used to detect TCs in climate, seasonal prediction, and weather forecast models, is assessed on its ability to produce a realistic TC track climatology in the ERA-Interim product over the 25-yr period 1989 to 2013. The analysis focuses on TCs that achieve gale-force (17 m s−1) sustained winds. Objective criteria were established to define TC tracks once they reach gale force for both observed and detected TCs. A lack of consistency between storm tracks preceding this level of intensity led these track segments to be removed from the analysis. A subtropical jet (STJ) diagnostic is used to terminate transitioning TCs and is found to be preferable to a fixed latitude cutoff point. TC tracks were analyzed across seven TC basins, using a probabilistic clustering technique that is based on regression mixture models. The technique grouped TC tracks together based on their geographical location and shape of trajectory in five separate “cluster regions” around the globe. A mean trajectory was then regressed for each cluster that showed good agreement between the detected and observed tracks. Other track measures such as interannual TC days and translational speeds were also replicated to a satisfactory level, with TC days showing limited sensitivity to different latitude cutoff points. Successful validation in reanalysis data allows this model- and grid-resolution-independent TC tracking scheme to be applied to climate models with confidence in its ability to identify TC tracks in coarse-resolution climate models.

Globally, temperate grasslands have been significantly degraded as a result of urbanisation, grazing and agriculture. Weeds now dominate most of these ecosystems, resulting in the loss of ecosystem services, reduced carrying capacity for farmers, and reduction of habitat for native plants and animals. This paper reviews the literature relating to temperate grassland restoration efforts across the globe, noting which techniques and combinations have been used successfully to reduce weed dominance and promote native recruitment and establishment. This review concludes that, using a combination of four restoration techniques, provided the highest level of success, with the caveat that, ongoing weed management should be budgeted for in all projects. There is no single optimal method for restoration and weed control, with success depending on specific site conditions and the scope and aims of particular projects. However, any form of target plant transfer was observed to significantly enhance the restoration's success and reduce exotic plant biomass. There is clearly a need for an increase in long‐term monitoring of restoration projects in order to make more confident assumptions.

A recently validated technique for detecting and tracking tropical cyclones (TCs) in coarse resolution climate models was applied to a selected group of 12 models from the Coupled Model Intercomparison Project (CMIP5) to assess potential changes in TC track characteristics in the Southern Hemisphere (SH) due to greenhouse warming. Current-climate simulations over the period 1970-2000 were first evaluated against observations using measures of TC genesis location and frequency, as well as track trajectory and lifetime, in seven objectively defined genesis regions. The 12-model (12-M) ensemble showed substantial skill in reproducing realistic TC climatology over the evaluation period. To address potential biases associated with model interdependency the analysis was repeated with an ensemble of five independent models (5-M). Results from both the 12-M and 5-M models were very similar, instilling confidence in the models for climate projections. Projected changes in TC track density between the current-and future-climate (2070-2100) simulations under the Representatives Concentration 8.5 Pathways (RCP8.5) were also assessed. Overall, projection results showed a substantial decrease (~1-3 per decade) in track density over most parts of the SH by the end of the twenty-first-century. This decrease was attributed to a significant reduction in TC numbers (~15-42%) consistent with changes in large-scale environmental parameters such as relative vorticity, environmental vertical wind shear and relative humidity. This study has important implications for regional-scale climate change and adaptation pathways for the vulnerable regions in the SH, particularly the small island countries in the Pacific.

Navua sedge [Cyperus aromaticus (Ridley) Mattf. & Kük.] is an aggressive perennial sedge native to equatorial Africa which has become problematic in many Pacific islands and wet tropical Queensland, Australia. It has had a significant impact on livestock grazing industry, sugarcane (Saccharum officinarum L.) and banana (Musa acuminata Colla) plantations and various other ecosystems. A laboratory-based research investigation was conducted to understand germination and emergence requirements under various environmental conditions, of three geographically varied populations sourced from South Johnstone (SJ), Mackay (M) and Nyleta Creek (NC) in Queensland. Germination was identified to be stimulated by light with no germination recorded under darkness. Populations SJ and NC had optimal germination at alternating temperatures of 25/15, 30/20 and 35/25 C whereas population M had optimal germination at 25/15 and 30/20 C. All populations recorded over 85% germination in all pH levels tested. Seeds of population SJ was more sensitive to salinity compared to populations M and NC, with SJ showing no germination at 100 mM whereas populations M and NC had 23% and 9% germination, respectively. An inverse relationship was observed between osmotic potential and germination, with no germination recorded at osmotic potentials below -0.8 MPa in any population indicating moisture availability is a critical requirement for germination. Exposing seeds to 120 C radiant heat completely inhibited germination in populations M and NC, whereas 3% of population SJ germinated following a 180 s exposure at 120 C. Seedling emergence decreased as planting depth increased. Emergence was greatest for seeds on the soil surface or at 0.5 cm burial depth, consistent with germination being stimulated by light. Knowledge of these biological characteristics of C. aromaticus seed germination will assist in investigation of suitable control actions for this species particularly in the early stage of its invasion into new areas, and contribute to significant reduction in the soil-stored seed bank.

African lovegrass [Eragrostis curvula (Schrad.) Nees] is a highly invasive C4 perennial grass that threatens global biodiversity. Appropriate management of the species has been hampered by a lack of knowledge of the species’ seed ecology, resulting in significant economic and environmental impacts within various environments. Consequently, this study explored the effects of a selection of environmental factors (photoperiod, alternating temperature, pH and salinity) by analysing several measures of germination on four geographically distinct populations of E. curvula to assist in its extirpation from infested sites. Seeds were collected in Australia from Maffra and Shepparton, Victoria; Tenterfield, New South Wales and Midvale, Western Australia. Key results showed that seeds from Maffra (54% vs. 79%), Tenterfield (38% vs. 61%) and Shepparton (34% vs. 71%) had significantly reduced germination in complete darkness compared to an alternating 12 hours light and 12 hours dark photoperiod, whereas Midvale had consistent germination (91% vs. 99%). Temperatures between 17/7 OC reduced germination for Maffra (42% vs. 73%), Tenterfield (34% vs. 55%) and Shepparton (33% vs. 59%) compared to the mean of all other temperature combinations, whereas, Midvale had consistent germination. Furthermore, germination for all populations was consistent between pH 4 and 9. For salinity, germination was significantly reduced at ≥100 mM for Maffra (29% vs. 67%), ≥150 mM for Tenterfield (29% vs. 94%) and Shepparton (39.5% vs. 81.5%), and 250 mM for Midvale (39% vs. 82%) compared to the mean of all other concentrations. Although each trial was conducted independently, they can be used to generate species targeted management. Such strategies include maintaining high levels of quarantine and hygiene programs to avoid future spread, where practical apply light-limiting strategies (mulching, tilling or scraping) for the Maffra, Tenterfield and Shepparton populations; and maintaining management efforts year round as the species can germinate under a wide range of conditions.