Potential distribution of selected invasive alien plants under current and future climate change scenarios in South Africa.

Invasive alien plants are one of the main causes for the decline of native biodiversity worldwide. Hence, it is crucial to understand the dynamics of invasive plants in the context of a changing climate. The main aim of this study was to evaluate the potential distribution of two major invasive alien plants, Prosopis spp and Acacia mearnsii, under current and future climate change scenarios across South Africa. The maximum entropy (MaxEnt) model was used with species occurrence data and bioclimatic variables. The Species occurrence data was obtained from the Global Biodiversity Information Facility (GBIF), while the bioclimatic variables were downloaded from the WorldClim database. The model evaluation metrics for training and test samples were the area under curve (AUC) of 0.76 and 0.77 for Prosopis spp, and 0.91 and 0.89 for A. mearnsii, respectively. It showed that MaxEnt performed well in mapping the distribution of both species. Model results indicated that the near-current potential distribution of Prosopis spp and A. mearnsii in South Africa is significant (93.8% and 9.7% of the total land area, respectively). With the projected climate, Prosopis spp showed an inconsistent result across the General Circulation Models (GCMs), projection times and climate change scenarios. However, with respect to the current potential distribution, the geographical ranges of A. mearnsii will significantly contract (by about 75%) due to climate change. Therefore, it is imperative that policy makers, environmental managers and other stakeholders implement integrated management and control strategies to restrict the distribution of Prosopis spp.

Clinico-pathological findings in natural cases of "mascadera" in goats.

"Mascadera" is a chronic emaciating neuropathy affecting goats; it produces significant economic losses in many regions and its cause is unknown. Here, the histological lesions found in 15 animals naturally affected by the disease are described. Complete necropsy was performed and tissue samples were collected for histopathological study. Severe atrophy of the masseter and buccinator muscles and tongue was observed, as well as vacuolar degeneration of neurons in the nuclei of the trigeminal, facial, and glossopharyngeal nerves. No relevant lesions were observed in other tissues. These findings and the clinical signs are consistent with those observed by other authors in animals spontaneously and experimentally intoxicated with Prosopis juliflora. The disease may be due to consumption of a similar species present in our country that is still unknown. Further research on the etiology and pathogenesis of this disease is needed to establish appropriate prevention guidelines.

Comparative analysis of C-glycosidic flavonoids from Prosopis spp. and Ceratonia siliqua seed germ flour.

Seed germ of South American algarrobo (Prosopis species) and European carob (Ceratonia siliqua) contains nutritionally interesting proteins, lipids and phenolics. Using reversed phase-HPLC-diode array detector and nanoflow-HPLC coupled to tandem mass spectrometry (MS/MS), we comparatively characterized and semi-quantified flavonoids from germ of three Argentinean algarrobo (Prosopis alba, Prosopis nigra and Prosopis ruscifolia) and one European carob species. The patterns of glycosylated flavonoids were very similar each other, confirming the taxonomic parentage of the species and supporting their functional similarity on a molecular basis, in view of the use of seed germ flour (SGF) for food applications. The predominant phenolic compounds were apigenin 6,8-C-di-glycoside isomers, namely isoschaftoside and schaftoside, accounting for 3.22-5.18 and 0.41-0.72 mg/g SGF, respectively. C. siliqua germ contained relatively high amounts of further glycosilated derivatives of (iso)schaftoside, which occurred at a lower abundance in Prosopis. Apigenin 6,8-C-di-glycosides have been described as potent α-glucosidase inhibitors, suggesting that food preparations obtained with Prosopis spp. and C. siliqua SGF might contribute to modulate the digestion of carbohydrates in humans. CHEMICAL COMPOUNDS: Isoschaftoside (PubChem CID: 13644661); Schaftoside (PubChem CID: 442658); Vicenin-2 (PubChem CID: 442664); Isovitexin (PubChem CID: 162350).

Decadal shifts in grass and woody plant cover are driven by prolonged drying and modified by topo-edaphic properties.

Woody plant encroachment and overall declines in perennial vegetation in dryland regions can alter ecosystem properties and indicate land degradation, but the causes of these shifts remain controversial. Determining how changes in the abundance and distribution of grass and woody plants are influenced by conditions that regulate water availability at a regional scale provides a baseline to compare how management actions alter the composition of these vegetation types at a more local scale and can be used to predict future shifts under climate change. Using a remote-sensing-based approach, we assessed the balance between grasses and woody plants and how climate and topo-edaphic conditions affected their abundances across the northern Sonoran Desert from 1989 to 2009. Despite widespread woody plant encroachment in this region over the last 150 years, we found that leguminous trees, including mesquite (Prosopis spp.), declined in cover in areas with prolonged drying conditions during the early 21st century. Creosote bush (Larrea tridentata) also had moderate decreases with prolonged drying but was buffered from changes on soils with low clay that promote infiltration and high available water capacity that allows for retention of water at depth. Perennial grasses have expanded and contracted over the last two decades in response to summer precipitation and were especially dynamic on shallow soils with high clay that have large fluctuations in water availability. Our results suggest that topo-edaphic properties can amplify or ameliorate climate-induced changes in woody plants and perennial grasses. Understanding these relationships has important implications for ecosystem function under climate change in the southwestern USA and can inform management efforts to regulate grass and woody plant abundances.