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Integrated population model reveals human- and environment-driven changes in Baltic ringed seal Pusa hispida botnica demography and behavior
No full textIntegrated population models (IPMs) are a promising approach to test ecological theories and assess wildlife populations in dynamic and uncertain conditions. By combining multiple data sources into a unified model, they enable the parametrization of versatile, mechanistic models that can predict population dynamics in novel circumstances. Here, we present a Bayesian IPM for the ringed seal Pusa hispida botnica population inhabiting the Bothnian Bay in the Baltic Sea. Despite the availability of long-term monitoring data, traditional assessment methods have faltered due to dynamic environmental conditions, varying reproductive rates, and recently re-introduced hunting, thus limiting the quality of information available to managers. We fit our model to census and various demographic, reproductive, and harvest data from 1988 to 2023 to provide a comprehensive assessment of past population trends, and predict population response to alternative hunting scenarios. We estimated that 20000–36000 ringed seals inhabited the Bothnian Bay in 2024, increasing at a rate of 3–6% yr–1. Reproductive rates have increased since 1988, leading to a substantial increase in the growth rate up until 2015. However, the re-introduction of hunting has since reduced the growth rate, and even minor quota increases are likely to reduce it further. Our results also support the hypothesis that a greater proportion of the population hauls out under lower ice cover circumstances, leading to higher aerial survey results in such years. In general, our study demonstrates the value of IPMs for monitoring wildlife populations under changing environments and for supporting science-based management decisions
Angiosperm radiation, diversification, and vegetation shifts through the Albian–Cenomanian of the northern Iberian Peninsula: Palynological evidence from the Las Loras UNESCO Global Geopark
No full textDuring the mid-Cretaceous (Aptian-Turonian), angiosperms diversified and expanded their range significantly, but were potentially affected by several environmental crises. The Iberian Peninsula is particularly relevant to studies of paleobotanical events through this interval owing to its intermediate position between Gondwanan and Laurasian floral provinces and its wealth of assemblages containing early angiosperms. The Las Loras UNESCO Global Geopark is a unique area for paleobotanical studies ofthe mid-Cretaceous in the Basque-Cantabrian Basin, which currently has a depauperate record of floral evolution through this interval. Our palynostratigraphical results have clarified the chronostratigraphic positions and improved correlation of various formations in the Las Loras region. These results assign the Escucha Formation to the lower-upper Albian, the Santa María de las Hoyas Formation to the middle Cenomanian with diachronous (upper Cenomanian) deposits towards the west, and the Abejar Formation to the lowermost upper Cenomanian. Our new paleoecological results and a review of previous palynological data reveal notable changes in plant communities in the Iberian Peninsula through the Albian-Cenomanian. A conifer-dominated flora prevailed through the early-middle Albian but a shift to more diverse communities with increased presence of angiosperms typified the late Albian-early Cenomanian. The middle Cenomanian was characterized by conifer dominance but with expanded angiosperm diversity marked by the first occurrence of the Normapolles group. Finally, the late Cenomanian featured sporadic dominance by angiosperms, particularly the Normapolles group, in deposits associated with the Oceanic Anoxic Event 2.This researchwas partially fundedby the Xunta de Galicia (Spain), through project EDC431C-2019/28,and the Las Loras UNESCO Global Geopark (I Convocatoria de Ayudasa la investigacion del Geoparque Las Loras 2020). Ivan RodríguezBarreiro was supported by a predoctoral fellowship from the Xuntade Galicia and European Social Fund (ED481A-2020/175). ArtaiSantos is supported by a postdoctoral fellowship funded by theSwedish Research Council Grant VR 2022-03920, managed byStephen McLoughlin.</p
Tenellisporites capillaris sp. nov., a new dispersed lycopsid megaspore from the Middle–Upper Triassic Badong Formation, Hunan Province, China
No full textDispersed megaspore fossils provide crucial insights into the diversity of heterosporous lycopsids through geological time. However, detailed systematic studies on Middle–Late Triassic dispersed lycopsid megaspores of the South China Block are lacking. Here, we report a unique dispersed lycopsid megaspore species, Tenellisporites capillaris sp. nov., from the Middle–Upper Triassic Badong Formation in Hunan Province, China. This trilete megaspore species is characterised by narrow, elevated, membraneous laesurae with ragged finger-like projections; a flattened equatorial zona; and single or rarely bifurcate spines with sharp tips on both the proximal and distal surfaces. These spines are connected basally to form a fine reticulum and gradually increase in thickness and length towards the equator. Ultrastructural analysis reveals that the megaspore wall consists of two layers: 1) a very thin and dense foot layer, 2) a thick, dense outer layer with parallel sporopollenin units. The outermost sporopollenin units transition to vertically arranged units where forming the spinous ornamentation. The morphological and ultrastructural characteristics indicate that the new megaspore species belongs to Isoetales. Our finding represents the first fossil record of Tenellisporites in Asia, enhancing our understanding of the palaeogeographic distribution and diversity of isoetalean lycopsids during the Middle–Late Triassic. This study was jointly supported by the National Natural Science Foundation of China (42325201), the Yunnan Province Science and Technology Department (202302AO370014), and Yunnan University (KC-24249875). S.M. is funded by a Swedish Research Council VR grant (2022-03920).</p
Exceptionally Preserved Setae: A Possible MorphologicalSynapomorphy of Cambrian Lophotrochozoans
No full textCambrian Lagerstätten yield exceptionally preserved fossils that have greatly improved our understanding of the origin andevolution of animal groups. Brachiopoda, a phylum of bivalved marine invertebrates nested firmly within the lophotrochozoanprotostomes, are widely recovered in such Lagerstätten. The marginal chitinous setae (or chaetae) of brachiopods are the mostcommonly described soft tissue and have been interpreted as performing a defensive and/or sensory role. Despite their relativelycommon appearance in Cambrian Lagerstätten, the origin, function, and evolution of setae in the Brachiopoda is poorly known.Here, we document exquisitely preserved setal structures from South China and Laurentia paleocontinents giving new insightsinto their formation, microstructure and preservation mode. New setae typically make their appearance within the follicle of aneighbouring older seta and then branches off laterally forming its own follicle. Setal microstructure is likely to be composed ofmany canals, highly comparable to setae of their recent counterparts. Moreover, setae recovered from these palaeo‐continentspresent different preservation: aside from the normal preservation of iron oxides and carbonaceous ingredients, some compositions of calcium are also detected in this originally chitinous organization. Investigating the evolutionary origins of chitinous setae, a specialized type found notably in lophotrochozoans such as brachiopods and annelids, reveals its presence inearly Cambrian stem groups. This character likely serves as a morphological synapomorphy in lophotrochozoan evolution.However, the dearth of morpho‐ultrastructure and comparative studies in Cambrian fossils presents a challenge in fullyunderstanding this evolutionary development.This contribution was funded by research projects from the National Key Research and Development Program of China (2023YFF0803601), the National Natural Science Foundation of China (42302010, 42072003), the China Postdoctoral Science Foundation (2023M732836), the Postdoctoral Fellowship Program of CPSF (GZB20230590), Department of science and technology of Shaanxi Province 2022TD-11, and 111 Project (D17013). Research of L.E. Holmer is supported by the Swedish Research Council (VR2018-03390), and by a Zhongjian Yang Scholarship from the Department of Geology, Northwest University. Research of Topper T.P. is supported by the Swedish Research Council (VR2017-05183 and VR2021-04295).</p
Boron isotopes trace an increase in subduction-driven recycling of fluid-mobile elements in the Neoarchean
No full textThe deep recycling of surface material into Earth’s mantle is an integral process governing global water and fluid-mobile element cycles. This recycling is largely predicated on subduction operating efficiently, which may not apply for the first two billion years of Earth’s history. Tracing the initiation and evolution of the modern deep fluid-mobile element cycle requires determining when the mantle first became modified by subducted surface-derived materials on a global scale. The B isotope system provides a unique geochemical parameter to test for early signatures of such recycling, given that B is enriched and isotopically fractionated at Earth’s surface, depleted in the mantle, and mobilized by fluids and fluid-rock interaction. In this study, B isotopes of granitoids from seven Archean cratons are analyzed to trace the early signatures of recycling of surface-altered materials. When filtered for alteration and (post-)magmatic B modification, the B isotope compositions of the sample set show substantial variation. The range exhibited by sanukitoids (−8.9 ‰ to −1.6 ‰, mean: −4.7 ‰, n = 5) overlaps with other granitoids (−15.8 ‰ to +8.0 ‰, mean: −8.6 ‰, n = 30), but the average B isotope composition of sanukitoids is higher than other granitoids. The granitoids reveal a temporal diversification towards, on average, higher 11B/10B values from the Neoarchean onward. The heavier B isotope values reflect the recycling of surface-derived B into the melt source along a geotherm that was cold enough to prevent total loss of B through dehydration reactions, consistent with a cold-subduction geotherm. The B data thus indicate that the subduction-driven recycling of surface-derived materials into the mantle became more prevalent since the Neoarchean, marking this era as the likely starting point for the modern deep fluid-mobile element and water cycle
Report of the Bryophyte Specialist Group 2024-2025 : In: IUCN SSC and Secretariat. Annual Report of the IUCN Species Survival Commission and Secretariat 2024-2025
No full textThe mission of the IUCN SSC Bryophyte Specialist Group (BSG) is to promote the exploration of bryological diversity acrossall geographic scales and its long-term conservatio
The complete mitochondrial genome of the common dace Leuciscus leuciscus (Teleostei: Leuciscidae)
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