Aquatic Conservation-Marine and Freshwater Ecosystems最新文献

Spatial–temporal patterns of biodiversity distribution provide critical insights into ecosystem responses to climate change. We chose the Bohai Sea, a temperate shelf sea highly influenced by climate change and human activities, as a case study to evaluate biodiversity dynamics. This study integrates presence–absence data of macrofaunal communities collected from 152 sampling stations (2011–2022) and employs ensemble species distribution models to assess the current and future habitat suitability of dominant species, functional traits and multidiversity. The findings reveal bottom salinity as the predominant factor driving macrofaunal distribution and biodiversity. The predictions indicate diverse responses: (1) no significant trends for species diversity or functional diversity indices; (2) expansion in habitat suitability for carnivorous feeders and species such as Sternaspis scutata, Moerella iridescens, Protankyra bidentata and Emplectonema gracile; and (3) contraction in deposit feeders and Alpheus digitalis. This study highlights the key role of thermal and salinity tolerance in shaping future species distributions, and that of functional redundancy in sustaining ecosystem resilience, and further advocates for adaptive management to support temperate ecosystem conservation amid climate change.

Marine protected areas (MPAs) act as essential conservation tools. However, biological invasions directly undermine the ability of these important conservation areas to meet their objectives by negatively affecting biodiversity, ecosystem functions and service provisioning. Currently, data on the distribution of marine alien species in South Africa are scarce and often outdated, with little known about invasions in MPAs. This reflects the absence of long-term monitoring programmes, a common challenge for many African countries. Recently, crowdsourced data platforms, including iNaturalist, have been used to support large-scale data collection. Beneficial due to their accessibility, these platforms provide data that cover broad temporal and spatial scales while not requiring funding. This study assessed the status of iNaturalist records for species known to be alien in South Africa, with a focus on MPAs. A total of 952 records were recovered, with 568 retained for analysis following the application of a confidence metric. Alien species were documented in 14 of the 29 South African coastal MPAs, with most species (15) recorded in the Table Mountain National Park MPA. This study documented three ascidians (Ciona robusta; Clavelina lepadiformis; Styela plicata) in natural habitats for the first time and extended the known range of the maritime earwig Anisolabis maritima by more than 1500 km, highlighting the pervasive nature of alien species in MPAs. This study presents the first use of iNaturalist data in a marine invasion context in South Africa and demonstrates the potential of this approach to enhance monitoring in resource-restricted under-surveyed MPAs throughout Africa.

Investigating individual home ranges within animal populations is critical to understanding community dynamics and identifying the drivers of population structure and substructure. Anthropogenic impacts such as habitat modification can have significant effects on the home range of marine predators but have rarely been investigated in free-ranging populations on a long-term basis. In environments where habitat quality is degrading, home range size is expected to increase for large predators as they may need to travel farther to find food. Using photo-identification data from 1999 to 2019 and kernel density estimates, we assessed the spatio-temporal dynamics of home range, residency and community structure within a resident population of bottlenose dolphins in Biscayne Bay, a highly urbanized waterway off the coast of Miami, Florida. General and core home ranges were estimated from 95% and 50% utilization distributions (UD), respectively. Two distinct communities were identified: a northern community and a southern community. The southern community exhibited significantly larger home ranges (95% UD = 126.88 ± 93.45 km², 50% UD = 32.54 ± 27.46 km²) compared to the northern community (95% UD = 68.46 ± 56.55 km², 50% UD = 17.0 ± 13.79 km²). A temporal analysis revealed an overall contraction of core home range for both communities over the course of the study period, significantly decreasing by 36.2% in the northern community and 25.7% in the southern community. The contraction in home range is contrary to what we would have expected in a heavily impacted environment experiencing habitat degradation, where expansion might be necessary to locate sufficient prey. In this population, however, continued use of familiar areas may facilitate the exploitation of limited resources and minimize energy costs in expanding into less familiar territory. Additionally, given the confined geography of Biscayne Bay, a contraction may also reduce competitive interaction among communities through resource partitioning.

Traditional vertical slot fishways (VSFs), designed primarily for larger fish species like salmon, often fail to accommodate smaller, weaker-swimming species, leading to low passage efficiency. To address this limitation, a novel V-shaped multi-slot fishway (VMSF) is proposed, offering improved passability for weaker swimmers. A comprehensive comparison between the VMSF and the VSF was conducted, focusing on flow field topology, operational flow rate and key hydraulic performance indicators. Meanwhile, to further optimize the VMSF structure, the design was analysed under different variations of V-shaped baffle angles and positions. Among the eight VMSF designs analysed at a water depth of 1.8 m, VMSF-2 was identified as the optimal solution. Compared to the VSF, VMSF-2 reduced the flow rate by 33.46% and decreased volume- and time-averaged velocity, turbulent kinetic energy, Reynolds shear stress, turbulent dissipation rate and turbulence intensity by 8.65%, 26.32%, 48.77%, 12.20% and 10.76%, respectively. Additionally, under four different operating conditions, VMSF-2 showed significant improvements in overall performance. This optimized design reduces fish fatigue, diversifies migratory routes and significantly improves both fish passage efficiency and hydraulic performance.

In June 2025, the Brazilian government reinstated the National Wetlands Committee (CNZU), dismantled in early 2019 by the former one. Although CNZU was re-established later that year, civil society was excluded, which raised serious concerns about the effectiveness of wetland conservation. As Brazil holds about 10% of global wetlands, CNZU's reinstitution, together with the creation of the National Institute of Science and Technology of the Brazilian Wetscape Network, reaffirms Brazil's commitment to the Ramsar Convention.

Odonata is a cosmopolitan, indicator group of insects residing on all continents except Antarctica, with notable species richness in Africa's tropical montane forests. In East Africa, this group is threatened by habitat loss and degradation driven by rapid population growth. This study investigated odonate assemblages and their conservation concern in Bwindi Impenetrable National Park (BINP, Afromontane) and Bugoma Central Forest Reserve (BCFR, mid-altitude) in the Albertine Rift in Uganda. From December 2022 to July 2023, 61 sites were cross-sectionally surveyed (26 in BCFR, 35 in BINP) to analyse community composition, habitat preferences, and conservation threats. Odonate key habitats in these forests were mapped. Nonmetric multidimensional scaling revealed distinct odonate communities in BCFR and BINP with limited overlap. Odonate diversity was computed using both Shannon diversity indices and species richness. BCFR registered a significantly higher overall species richness (median = 3.0) than BINP (median H = 2.0, p < 0.01). However, BINP hosted more range-restricted and globally threatened species, with a higher threat-based score (median TBS = 2.00) compared to BCFR (median TBS = 0.00, p < 0.01). Threatened species such as Neodythemis munyaga (Endangered) and Albertine Rift endemics such as Stenocypha molindica and Stenocypha jacksoni were strongly associated with BINP's high-altitude, pristine streams characterized by clear water with low salinity, total dissolved solids and electrical conductivity. Substantial anthropogenic pressures were recorded in BCFR, threatening critical odonate habitats. We emphasise the urgent need for targeted conservation efforts to preserve the forest ecosystem services and their unique odonate diversity.

The jaguar cichlid (Parachromis managuensis), an invasive species native to Central America, was first recorded in Feitsui Reservoir, Taiwan, in 2014. From 2014 to 2024, 846 individuals were captured, with abundance increasing notably from 2018. Stomach content analysis revealed predation on native crustaceans (Caridina, Macrobrachium) and native fish (Sinibrama macrops), suggesting potential ecological impacts. Growth analysis indicated negative allometric growth and signs of growth retardation in larger individuals. The decline of S. macrops may be linked to increasing predation. This study marks the northernmost record of this species in East Asia and raises concerns about its ecological impact.