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Investigators in the cognitive neurosciences have turned to Big Data to address persistent replication and reliability issues by increasing sample sizes, statistical power, and representativeness of data. While there is tremendous potential to advance science through open data sharing, these efforts unveil a host of new questions about how to integrate data arising from distinct sources and instruments. We focus on the most frequently assessed area of cognition - memory testing - and demonstrate a process for reliable data harmonization across three common measures. We aggregated raw data from 53 studies from around the world which measured at least one of three distinct verbal learning tasks, totaling N = 10,505 healthy and brain-injured individuals. A mega analysis was conducted using empirical bayes harmonization to isolate and remove site effects, followed by linear models which adjusted for common covariates. After corrections, a continuous item response theory (IRT) model estimated each individual subject’s latent verbal learning ability while accounting for item difficulties. Harmonization significantly reduced inter-site variance by 37% while preserving covariate effects. The effects of age, sex, and education on scores were found to be highly consistent across memory tests. IRT methods for equating scores across AVLTs agreed with held-out data of dually-administered tests, and these tools are made available for free online. This work demonstrates that large-scale data sharing and harmonization initiatives can offer opportunities to address reproducibility and integration challenges across the behavioral sciences.
For the Western Plains of New South Wales, 213 plant communities are classified and described and their protected area and threat status assessed. The communities are listed on the NSW Vegetation Classification and Assessment database (NSWVCA). The full description of the communities is placed on an accompanying CD together with a read-only version of the NSWVCA database.
The NSW Western Plains is 45.5 million hectares in size and covers 57% of NSW. The vegetation descriptions are based on over 250 published and unpublished vegetation surveys and maps produced over the last 50 years (listed in a bibliography), rapid field checks and the expert knowledge on the vegetation. The 213 communities occur over eight Australian bioregions and eight NSW Catchment Management Authority areas. As of December 2005, 3.7% of the Western Plains was protected in 83 protected areas comprising 62 public conservation reserves and 21 secure property agreements. Only one of the eight bioregions has greater than 10% of its area represented in protected areas. 31 or 15% of the communities are not recorded from protected areas. 136 or 64% have less than 5% of their pre-European extent in protected areas. Only 52 or 24% of the communities have greater than 10% of their original extent protected, thus meeting international guidelines for representation in protected areas. 71 or 33% of the plant communities are threatened, that is, judged as being ‘critically endangered’, ‘endangered’ or ‘vulnerable’.
While 80 communities are recorded as being of ‘least concern’ most of these are degraded by lack of regeneration of key species due to grazing pressure and loss of top soil and some may be reassessed as being threatened in the future. Threatening processes include vegetation clearing on higher nutrient soils in wetter regions, altered hydrological regimes due to draw-off of water from river systems and aquifers, high continuous grazing pressure by domestic stock, feral goats and rabbits, and in some places native herbivores — preventing regeneration of key plant species, exotic weed invasion along rivers and in fragmented vegetation, increased salinity, and over the long term, climate change.
To address these threats, more public reserves and secure property agreements are required, vegetation clearing should cease, re-vegetation is required to increase habitat corridors and improve the condition of native vegetation, environmental flows to regulated river systems are required to protect inland wetlands, over-grazing by domestic stock should be avoided and goat and rabbit numbers should be controlled and reduced. Conservation action should concentrate on protecting plant communities that are threatened or are poorly represented in protected areas.
The remnant natural vegetation (excluding native grasslands) of the Guyra 1: 100 000 map sheet area was sampled by way of 312 20 m × 20 m plots in which all vascular species were recorded using a modified Braun-Blanquet abundance rating. Sampling was stratified to cover the environmental factors of substrate, topographic position and altitude. Floristic analyses used the Kulczynski coefficient of dissimilarity in an agglomerative hierarchical cluster analysis and multidimensional scaling ordinations. Twenty-one plant communities were selected from the cluster analysis. The contribution of species to these groupings was investigated using a fidelity analysis. Another three communities were distinguished from aerial photographs and field traverse. These 24 plant communities are described and all except riparian vegetation are mapped. Their extent was mapped using aerial photography and ground traverses. The vegetation map was digitised at a scale of 1:25,000 but has been reduced to 1:100,000 for this publication. The minimum area mapped is 1 ha.
Eight hundred and eighty-nine plant taxa are reported for the study area, 681 of which were recorded during the survey. Common families are Poaceae, Asteraceae, Fabaceae, Myrtaceae, Orchidaceae and Cyperaceae. The status of the 28 nationally or State listed rare or threatened plant species, and other regionally rare species recorded in the area, is discussed. Some plant communities, such as those dominated by the stringybarks Eucalyptus caliginosa and Eucalyptus laevopinea, are ubiquitous in the landscape. Other communities are restricted in their geographic extent and contain a distinct suite of species. These included heath swamps, some forests on leucogranite and wetland vegetation in lagoons on basalt plateaux. 74% of the native woody vegetation has been cleared. This has particularly affected plant communities on higher nutrient soils including Eucalyptus viminalis and Eucalyptus dalrympleana subsp. heptantha open forest on basalt plateaux, Eucalyptus nova-anglica woodland in valleys, and Eucalyptus blakelyi and Eucalyptus melliodora woodland on sediments at lower altitudes. Most of the remnants have been grazed by stock thus influencing the understorey structure and species composition. Upright forbs and Acacia would appear to be less common now than prior to European settlement. Dieback of eucalypts over the last two decades has compounded the impacts of clearing. Logging and firewood cutting affects some plant communities. Weeds are most invasive where understorey disturbance is greatest, which is mainly in the small remnants on higher nutrient soil (basalt and sediments). Most of the lagoons in the study area have been drained or impounded, thus depleting wetland vegetation. Changes to fire regimes in the forest remnants may also have altered the populations of fire-dependent species. Most of the plant communities are poorly represented in conservation reserves. Conservation initiatives on private land are required to protect most of the communities. Key sites for conservation are listed.