North Carolina Natural Heritage Program

The Middle Tonian tectonic setting of the Jiangnan Orogen, South China, remains intensely debated, and is centered on two competing models: subduction–collision versus mantle plume. This study addresses this critical knowledge gap through an integrated, multi-proxy investigation of the Middle Tonian Fanjingshan Group. This region preserves a continuous volcano-sedimentary and magmatic record, offering key insights into the orogen’s full lifecycle. To test these hypotheses, we employed a synthesis of geological survey, sediment provenance analysis, detrital zircon U-Pb geochronology of clastic rocks to determine sediment provenance and basin evolution, and petrogenetic study of coeval magmatic suites (pillow lava, mafic–ultramafic sills, and granitoids) to evaluate their magmatic processes and tectonic setting. Analysis of 1736 detrital zircon U-Pb ages from Middle Tonian strata reveals a four-stage provenance evolution: (1) SW Yangtze sources in a passive margin basin before 870 Ma; (2) bidirectional sources in an 870–835 Ma arc-derived basin; (3) syn-collisional detritus during 835–820 Ma amalgamation; and (4) post-collisional and northern Yangtze inputs in an 800 Ma rifting basin. Geochemical data from ~845–840 Ma basalts and coeval sills reveal calc-alkaline affinities and marked subduction-fluid signatures. Their calculated mantle potential temperature (1404 °C) is significantly lower than that expected for plume-derived melts (1570 °C), which is consistent with melting in a subduction-modified mantle wedge, supporting a continental rear-arc basin setting. The ~845–832 Ma mafic–ultramafic sills exhibit symmetrical geochemical zoning and two-stage emplacement, recording sustained magma recharge in the rear-arc basin. Furthermore, the ~830 Ma Fanjingshan granite is identified as a crust-derived, syn-collisional S-type granite. Synthesizing these findings, we demonstrate that the sedimentary and magmatic records collectively point to plate margin setting. A four-stage tectonic model is suggested: (1) pre-870 Ma passive margin without significant magmatic activity; (2) 870–835 Ma continental arc development at an active continental margin; (3) 835–820 Ma Yangtze–Cathaysia collision; and (4) post-820 Ma post-orogenic rifting. This work provides a robust regional case study, demonstrating that integrating records of deep magmatic processes with coeval shifts in sedimentary provenance and basin architecture is essential to reconstruct the complete evolution of ancient orogens.

Rhodora, which began publication in 1899, publishes work relating to the botany of North America and covers topics such as biogeography, conservation biology, ecology, evolution, floristics, paleobotany, population genetics and systematics.

Clemmys guttata (Spotted Turtle) is a widespread species of regional conservation concern throughout the eastern United States and Canada, relying upon mosaics of upland and wetland habitats. Spotted Turtles exhibit late maturity and low annual reproductive potential; as a result, many populations are vulnerable to decline and reduced connectivity due to elevated rates of anthropogenic disturbance and mortality. We assessed 3 Spotted Turtle populations that were initially studied between 1989 and 1995 on patchworks of private and public (watershed and state forest) land using mark–recapture methods and a combination of open- and closed-population models. During the initial studies, the 3 populations were estimated to support 98, 18, and 43 turtles, respectively. Our population models for the same sites during 2018 or 2019 provided estimates of 92.3, 25.8, and 36.6 turtles, respectively, suggesting limited evidence of growth or decline over more than 25 years at all 3 sites, though fluctuations were observed. We attribute the lack of significant change in population size at these sites to their landscape context: all 3 are situated within areas >600 ha with no public road access, allowing turtles to shift habitat in response to vegetation succession, hydrological shifts, or other changes and buffering them against roadkill or other anthropogenic threats. We also documented variation in population parameters across both space and time; for example, annual survival estimates varied from 0.924 to 0.986 at the sites, emphasizing the need for locally specific information and long-term studies to inform conservation decisions at both the site and species level.

ObjectiveFreshwater mussels of the order Unionoida are among the most imperiled taxa in North America, and many species are undergoing enigmatic decline without fully understood causation. Disease pathology and parasitology have been identified as areas with significant knowledge gaps in relation to these declines. We investigated a shell deformity of unknown cause that is widespread in northeastern North America by adding to the clinical description from a mussel assemblage in Massachusetts with a deformity prevalence exceeding 50%. We build upon previous qualitative descriptions of this deformity with investigations of shell morphology and mussel age.MethodsWe conducted a qualitative survey of the mussel community to evaluate the prevalence of deformity. Mussels were classified as deformed based on the presence of a distinct truncation of the posterior margin of the shell. For the eastern elliptio Elliptio complanata, we evaluated the shell height, shell length, and height : length ratio of animals classified as deformed versus normal and we conducted a comparison to a reference population. We also incorporated shell thin sectioning and aging to qualitatively describe the deformity in cross section and to compare age distributions between deformed and normal eastern elliptio.ResultWe observed the presence of this deformity in four species, including the eastern elliptio, eastern lampmussel Lampsilis radiata, eastern pearlshell Margaritifera margaritifera, and creeper Strophitus undulatus. In cross section, the deformity appeared to be caused by repeated disturbance in growth in the posterior portion of the shell. Deformed eastern elliptio had markedly shorter shells for a given shell height when compared to normal and reference mussels, and they tended to be older at shorter shell lengths than normal mussels from the same site.ConclusionThe cause of the shell deformity in the United States remains unknown, although it appears similar in description to the deformity caused by a commensal midge, Xenochironomus canterburyensis, which infects a distantly related freshwater mussel in New Zealand. We highlight potential causes and the need for further investigation.

Rhodora, which began publication in 1899, publishes work relating to the botany of North America and covers topics such as biogeography, conservation biology, ecology, evolution, floristics, paleobotany, population genetics and systematics.

Summary During their northward migration, Red Knots Calidris canutus rufa stop at the Lagoa do Peixe National Park in the extreme south of Brazil to build up fat reserves for their journey to their Canadian breeding grounds. We tracked five Red Knots with PinPoint Argos-75 GPS transmitters to investigate differences in migration strategies from this stopover. Tracked birds used two different routes: the Central Brazil route and the Brazilian Atlantic Coast route. One bird flew 8,300 km straight from Lagoa do Peixe to the Delaware Bay (USA). Another bird stopped in Maranhão (north-east Brazil) and a third one used a yet unknown environment for the species, the mouth of the Amazon River at Baía Santa Rosa, Brazil. These two birds made short flights, covering stretches of 1,600 km to 3,600 km between stop-overs, where they stayed from 4 to 18 days. Our study highlights the occurrence of intrapopulation variation in migratory strategies and reveals the connectivity of environments that are essential for the viability of rufa Red Knot populations.

The elements in blood normally reflect the levels in prey, indicating a recent exposure. Laughing gulls (Leucophaes atricilla) eat mainly horseshoe crab eggs (Limulus polyphemus) in the spring in Delaware Bay, New Jersey. The levels of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in the blood of laughing gulls foraging on crab eggs were examined in Delaware Bay to provide information on a species that is normally a generalist, and to determine if the levels of these elements were similar in 2019 and 2022/2023, were intercorrelated, and were related to those in crab eggs. Hg increased from 2019 (136 ± 31 ng/g) to 2022/2023 (473 ± 75 ng/g), while Cd and Se decreased. There were some significant correlations among elements and a close relationship between the element levels in blood and those in crab eggs collected in the same month (except for As). The levels differed between laughing gulls and three species of shorebirds for As and Cd. The elements in the blood of gulls and shorebirds should be similar because they eat mainly the same eggs in the same places. A significant proportion of laughing gull blood samples had levels of Hg and Se that were above the levels associated with adverse effects, which requires further examination.

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

In this issue of the North Carolina Medical Journal, authors highlight the challenges and opportunities facing North Carolinians as they strive to live healthier, longer, productive lives. The articles shine light on how individuals, caregivers, and the state as a whole can address the fiscal impact of providing services for the most vulnerable, while also promoting the well-being of all.