Scientific Services

Illegal trade in leopard tortoises Stigmochelys pardalis is widespread, yet the origins of confiscated S. pardalis are often unknown. Accurate assignment to source populations is essential for informed conservation management and release. We expanded and tested a genetic reference database for assigning S. pardalis to their original wild populations in KwaZulu-Natal Province, South Africa, and Eswatini. We added 50 newly genotyped wild S. pardalis sampled across these regions to the database and then evaluated the updated database by sampling and assessing 50 S. pardalis of unknown geographic origin held at a rehabilitation centre in KwaZulu-Natal. Genetic assignment indicated that only a single S. pardalis at the rehabilitation-centre may have originated from KwaZulu-Natal, highlighting the extent of illegal trade, translocation, and possession of S. pardalis. Individuals of verified regional origin were subsequently rehabilitated and translocated for soft release at appropriate sites.

The capacity of nutrient-limited forests to enhance carbon (C) sequestration under elevated CO2 (eCO2) remains a critical uncertainty in C cycle modeling. While existing evidence suggests that low phosphorus (P) bioavailability may constrain CO2 fertilization effects on plant growth, the extent to which this limitation modulates ecosystem responses to eCO2 in forests adapted to P-deficient soils remains poorly understood. Here, using eight P-enabled models, we simulated the magnitudes and mechanisms through which P bioavailability interacts with eCO2, emulating an ecosystem-scale P enrichment experiment at a P-limited Eucalyptus forest undergoing long-term Free-Air CO2 Enrichment. While models predicted pronounced P effects on tree growth, P enrichment unexpectedly did not increase the CO2 effects on tree growth and ecosystem C sequestration. Models prioritized either CO2-driven or P-driven growth, but rarely both. This tradeoff emerged due to model-specific assumptions on 1) partitioning of the extra P in soil labile versus nonlabile pools; 2) plant photosynthetic acclimation to P deficiency; 3) C and nutrient use strategies regulating plant size and allocation; and 4) microbial-driven soil decomposition processes. By generating divergent yet biologically plausible outcomes, these predictions establish critical testable hypotheses for empirical research and highlight multiple P-related pathways that may influence the future land C sink.

ABSTRACT Subsurface excavations, paleoenvironmental sampling, and Bayesian modeling clarify upland field development in Kula, Maui. We report 26 radiocarbon determinations from 13 agricultural and two ritual feature complexes associated with swale terraces, enclosure walls, and water channels. We model five architectural phases: Preconstruction, Primary Construction, Secondary Modification, Enclosure Works, and Post-European Reuse. Preconstruction land use begins at least in the late 13th–15th centuries a.d., followed by terrace expansion, mainly from the 14th–17th centuries a.d., and later rebuilding on aggraded swales. Enclosure Works appear chiefly in the late 17th–early 19th centuries a.d. and likely supported plot subdivision and pig management. Paleoecological and faunal records indicate persistent open shrubland, trees concentrated along field margins, more warm-season grasses, and increased fire use and crop processing without forest recovery. Terraces and channels redistributed stormwater and soil moisture in a dry upland setting without perennial streams, creating a district-scale productive system linked to ritual authority and wider dryland and wetland economies.

Killer whales (Orcinus orca) are cosmopolitan apex predators that interact with numerous species, including sharks, skates, and rays (subclass Elasmobranchii). Interactions between killer whales and elasmobranchs have garnered attention from the scientific community, but the dynamics of these events are poorly understood, as interactions are often challenging to observe. In this study, we collated imagery of interactions between killer whales and elasmobranchs to create the first image-based repository of interspecific interactions between marine predators. A total of 320 photos and videos from 82 unique interactions were collected from 12 countries. A minimum of 18 elasmobranch species across 16 genera were identified from the imagery. Furthermore, 10 different interaction types were documented, encompassing both predatory and non-predatory behavior. This dataset can provide insight into various research topics, including killer whale predation techniques, elasmobranch behavior, and the identification of individual killer whales that specialize in elasmobranch prey. As a new and openly accessible resource, this dataset provides the foundation to support future ecological and behavioral research on killer whale and elasmobranch interactions.

Savannas are fire-prone ecosystems that contribute substantially to global fire emissions, but these emissions may be partly offset by deposition of fire-derived, persistent pyrogenic carbon (PyC) in soils. Although estimates of PyC contributions to soil organic carbon (SOC) storage in savanna exist, factors driving its accumulation remain unclear due to limited measurements with consistent methods. To address this, we sampled 253 sites across tropical savannas in Kruger National Park, South Africa, spanning broad gradients in fire regimes, grass biomass, rainfall, and soil texture. Here we show, PyC measured with H2O2/HNO3 digestion contributed, on average, 14.08% (se = 0.36%, n = 253) of SOC in surface soils, with values up to 40%. While fire frequency and grass biomass influenced soil PyC stocks, savannas with higher clay content and lower rainfall – conditions favoring PyC preservation – tended to accumulate more. These results demonstrate PyC’s significant contribution to SOC storage and highlight environmental factors driving its accumulation in tropical savannas, providing an empirical basis for understanding fire’s role in the savanna carbon cycle.

Australia is largely dependent on immigrant workers to bridge the employment gap in the agricultural sector and in agriculture-related food production; this poses a potential risk of the introduction and transmission of non-endemic vaccine preventable disease. We report the response to a Salmonella Typhi (S. Typhi) outbreak amongst workers from the Pacific Australia Labour Mobility (PALM) scheme in regional Queensland. A cluster of invasive Salmonella infections was investigated in accordance with the Communicable Diseases Network Australia guidelines. Active case finding of the at-risk group was undertaken to identify potential causal links and further transmission. Three confirmed cases of S. Typhi were reported, all male, with a median age of 31 years (range: 29-33 years). All cases were hospitalised and were managed with antibiotics and supportive care, with a median illness duration of nine days. Full recovery was reported for all cases, without complications. No recent travel history or contact with a recent typhoid case were reported. We identified 310 individuals in the exposed cohort, with a median age of 31 years (range: 22-55 years), all males. Of the exposed cohort, 305/310 individuals (98·4%) provided a faecal sample for S. Typhi testing; all returned a negative result. Genomic sequencing concluded the likely source of infection in this outbreak was chronic carriage of S. Typhi. Australia has had a significant increase in the number of PALM workers in regional areas, particularly within the agricultural sector, to mitigate employment gaps. A greater emphasis on culturally appropriate and linguistically sound hand hygiene education, and consideration of pre-employment health checks and vaccinations in these workers, would be beneficial in the reduction of communicable disease outbreaks.

Abstract In Earth history, our understanding of how large‐bodied herbivores shape a variety of ecosystem processes is limited by the quality of paleoecological proxies for herbivore composition and abundance. Fecal stanols are lipids that can be produced by microbes within animal digestive systems and that could remedy this dearth of proxies. We used two multi‐decadal herbivore exclosures in Kruger National Park, South Africa, to constrain whether and how biomarker signatures preserve signals of herbivore abundance. Soil samples and dung counts were collected along transects across crests, mid‐slopes, and sodic sites inside and outside exclosures. Soils were analyzed for steroid (sterols and stanols) concentrations and distributions. We found that stanol concentrations were significantly greater in sodic soils outside exclosures, where herbivore dung densities were greatest. In contrast, sterol concentrations did not differ between treatments. Ratios of stanol isomers to sterols, which account for both compound degradation and source, increased strongly with herbivore dung counts. Finally, while herbivore species compositions influenced steroid distributions, total herbivore abundance was their strongest predictor. Further calibration is needed, but this work provides strong preliminary evidence that wild herbivore populations are quantitatively recorded by fecal biomarker distributions.

Tea (Camellia sinensis) leaves and ginger (Zingiber officinale) rhizomes are very rich in polyphenolic compounds, majorly catechins, which are very useful in the management of several disease conditions. In this study tea leaves were blended with ginger rhizomes at different ratios (2:1, 1:2, 1:1), while 100% tea or ginger served as control. The dry sample powders were extracted with distilled water and administered to a group of 30 male albino rats of the Wistar strain alongside standard rat chow ad libitum. The aqueous extracts were fed to the animals via oral gavage for 18 days, at the end of which they were starved for 3 h, anaesthetized with chloroform and sacrificed. Blood samples were collected for haematological analyses and liver and heart were excised for histopathological examinations. Amino acid analysis was also carried out on the powdered samples of tea, ginger and their blended ratios. The results show that methionine was the most abundant essential amino acid (7.18 – 8.06 g/100 g protein) in all the composited samples, except in 100% ginger powder which had tryptophan as the most abundant (6.68 g/100 g protein). Histidine was the most limiting essential amino acid in all the samples, while arginine was the most abundant conditionally essential amino acid in green tea sample (8.22 g/100g protein). The results of haematological and histopathological examinations showed improvements in organs and overall well-being of the rats owing to the synergistic action of combined tea and ginger extracts. Findings in this study highlight the potentials of consuming tea-ginger blends for needed improvements in the nutrition and health status of consumers.