Multi-decadal trends in large-bodied fish populations in the New South Wales Murray-Darling Basin, Australia

Context: Native fish populations in Australia's Murray-Darling Basin (MDB) have experienced severe declines since European settlement. Information on their status is needed to guide management and recovery. Aims: To quantify trends in MDB fish populations in New South Wales (NSW) from 1994 to 2022. Methods: Relative abundance, biomass, and size structure were examined using generalised additive mixed models at NSW MDB and river catchment (valley) scales for five native species (Murray cod, Maccullochella peelii, golden perch, Macquaria ambigua, silver perch, Bidyanus bidyanus, Macquarie perch, Macquaria australasica, freshwater catfish, Tandanus tandanus) and one alien species (common carp, Cyprinus carpio). Key results: There was strong inter-annual variation in relative abundance, biomass and population structure for all species. At the Basin scale, relative abundance of Murray cod, golden perch and common carp increased across the time series, with no clear trends for silver perch, Macquarie perch or freshwater catfish. Patterns in relative abundance, biomass, and population structure were variable among valleys for most species. Conclusions and implications: Although native fish populations in the MDB remain degraded and face escalating threats, recent increases in the abundance of some native species are an encouraging sign that integrated restoration efforts can improve the outlook for native fish

Cognitive Neuropsychology of HIV-Associated Neurocognitive Disorders

Advances in the treatment of the human immunodeficiency virus (HIV) have dramatically improved survival rates over the past 10 years, but HIV-associated neurocognitive disorders (HAND) remain highly prevalent and continue to represent a significant public health problem. This review provides an update on the nature, extent, and diagnosis of HAND. Particular emphasis is placed on critically evaluating research within the realm of cognitive neuropsychology that aims to elucidate the component processes of HAND across the domains of executive functions, motor skills, speeded information processing, episodic memory, attention/working memory, language, and visuoperception. In addition to clarifying the cognitive mechanisms of HAND (e.g., impaired cognitive control), the cognitive neuropsychology approach may enhance the ecological validity of neuroAIDS research and inform the development of much needed novel, targeted cognitive and behavioral therapies

Adaptive responses to directional trait selection in the Miocene enabled Cape proteas to colonize the savanna grasslands

Directional selection occurs when the agent of selection changes direction or strength such that fitness of a dominant trait is relaxed or even annulled, and simultaneously the fitness of a rare opposing trait is intensified or even becomes essential. The value of this concept in evolutionary ecology was demonstrated by mapping fire- and growth-related traits and regional affinity onto a molecular-based chronogram for 91 species of Protea that is widespread in the shrubland and grassland biomes of southern Africa. The crown clade arose 22-34 million years ago (Oligocene) in the Cape shrublands that was increasingly winter wet, nutrient and water-limited, and moderately fireprone. This environment favoured nonsprouting and resprouting shrubs, on-plant seed storage (serotiny) and strong sclerophylly. Adjoining grasslands developed 7-19 million years ago (mid-late Miocene) that were summer wet, carbon-limited and highly fireprone. This favoured resprouting only, seed release at maturity, and taller plants with large leaves and weak sclerophylly. Thus, for successful migration from the shrublands to grasslands, the dominant ancestral condition of serotiny was replaced by almost universal nonserotiny in response to a change in fire type, and the dominant ancestral condition of nonsprouting by universal (lignotuberous) resprouting in response to more frequent fire. Taller plants with epicormic resprouting and larger, softer leaves were also promoted, due to the change in fire type, growing season and declining pCO2, but appeared 4-6 million years later. Thus, adaptive radiation via directional selection in the novel grassland environment required a suite of adaptive responses to various selection pressures that led to species radiation in the vast habitat available now constrained by stabilizing selection. The biology of grasses in savanna grasslands may well have changed during the Miocene/Pliocene but so did the woody plants that invaded them