Sedentary Species Research Articles

Population genetics of Macrognathus siamensis (Synbranchiformes: Mastacembelidae): Implications for non-migratory fishery resources in the Mekong River basin

The spotted spiny eel, Macrognathus siamensis is an economically important freshwater fish in the Mekong River basin, which is undergoing dramatic biodiversity changes due to anthropogenic impacts. The species is non-migratory, with a moderate larval duration that facilitates downstream genetic connectivity. Restriction site-associated DNA sequence datasets that includes 3736 and 1244 single nucleotide polymorphisms representing putatively neutral loci, from all geographic sites and without the Tachileik site, indicate strong population structure in this sedentary fish, with a significant isolation-by-distance signature. This structure reflects isolation of tributary populations and downstream dispersal of these distinct populations to mix in the Mekong mainstem and contributes to increased genetic diversity in the lower reaches of the Mekong basin. Genetic data indicates that the dispersal of eggs and larvae downstream is not impeded by Khone Falls and that the falls prevent upstream dispersal of eggs and larvae. Despite this downstream connectivity, there is a strong population structure among above- and below-Khone Falls groups. An analysis of outlier loci putatively under selection provides evidence that the difference between connected metapopulations above and below the falls is due to the fundamental differences in environmental regimes. We hypothesize that instead of a physical barrier, the falls simply represents a demarcation between previously recognized upstream limited-floodplain environments and downstream extensive-floodplain environments. These findings emphasize the need to monitor genetic diversity of key sedentary fishery species to assess whether proposed dams along the river could affect genetic diversity downstream. This genetic diversity is particularly important for the resilience of downstream populations because of the many environmental impacts caused by dams, land use, and climate change. Early detection of reduced downstream genetic diversity could trigger remediation programs to ensure resilience and continued fisheries productivity of important non-migratory fish resources.

Presence-only fisheries bycatch data produce biased species distribution predictions for Alcyonacean corals on British Columbia’s continental shelf and slope

Sedentary benthic species such as Alcyonacea corals form critical habitat for fishes and invertebrates. Assessing anthropogenic risks to these organisms requires unbiased, species distribution models (SDMs) that attempt to map probabilities of coral presence in relation to bio-physical ocean characteristics; however, in deep-water settings, the accuracy of SDMs is highly variable and dependent on spatial and taxonomic resolution. Here we investigated how data and model types affect SDM predictions of Alcyonacea probability of presence. We compared predictions from generalized additive models (GAMs) fitted to presence-absence observations over a stratified-random survey design with predictions from maximum entropy models (Maxent) fitted to presence-only bycatch records from commercial fisheries. We use a simulation analysis to show that both model types (i.e., GAM or Maxent) using presence-only bycatch data produced biased estimates of species distribution. Additionally, the maxent model fit using presence-only bycatch data produced biased estimates of performance metrics (AUC, TSS) that were overly optimistic. This study demonstrates a need for presence-absence data collected using a robust survey sampling design to fit SDMs that will better inform marine protected area placement while minimizing unnecessary economic losses, such as forgone fishing yield, due to sub-optimal placement.

Biogenic reef creation and biodiversity enhancement by an offshore longline mussel farm

As the mussel farming industry moves offshore, there is a need to fill evidence gaps on its ecological impacts. Over eight years, this research presents the results of a long-term monitoring study of the UK’s first large scale offshore mussel farm following a BACI (Before-After Control-Impact) approach to evaluate the temporal and spatial effects of the farm on benthic habitat and epibenthic species assemblages. Situated in historical fishing ground, the farm is located on a degraded seabed ecosystem dominated by soft sediment. After seven years of farming, damaged seabed increased its complexity, with biogenic reef being created (30 % increase). The structure is attracting a significantly increasing diversity and abundance of sessile, sedentary and mobile species to the area compared to control sites. The abundance and diversity of commercial species increased compared to far control sites and certain commercial species were exclusively recorded beneath the mussel headlines: Cancer pagurus, Maja squinado and Necora puber. Results are discussed through a three mechanisms framework: Species recruitment, settlement, and subsidy. Results from this study are crucial to support policymakers develope a sustainable offshore industry as part of the blue economy that can both produce sustainable protein and contribute to marine conservation objectives as ‘other effective area-based conservation measures’ (OECM). This study reports how low-trophic farming can support nature restoration and recovery.

Unexpected mismatches in population structure among marine mussel life‐history stages reveal the true scales of planktonic larval dispersal

AbstractStudies investigating gene flow in sessile or sedentary marine species typically draw conclusions about larval dispersal by investigating genetic structure of adults. Here, we generated microsatellite data from adults, recruits, settlers and planktonic larvae of the brown mussel, Perna perna, from the southeast coast of South Africa, and identified a consistent mismatch in genetic structure between the adults and all earlier life stages. While adults could be assigned to two major geographical groups (western and eastern), most of the early‐stage mussels were strongly affiliated with the eastern group. This suggests that few of the early‐stage individuals present in the western portion of the sampling range will eventually establish themselves in the adult population, highlighting the importance of post‐recruitment processes as drivers of population structure. Our findings caution against the exclusive use of genetic data generated from adults to assess population connectivity facilitated by the dispersal of planktonic propagules.

Surviving global change: a review of the impacts of drought and dewatering on freshwater mussels.

The increase in the frequency and intensity of droughts and heatwaves caused by climate change poses a major threat to biodiversity. In aquatic systems, sedentary species such as freshwater mussels are generally considered more vulnerable to changes in habitat conditions than mobile species such as fish. As mussels provide important ecosystem services, understanding the impacts of drought on freshwater mussels is of particular importance for the management of overall functioning of aquatic ecosystems. We used a comprehensive literature search to provide a systematic overview of direct and indirect effects of drought on freshwater mussels (Bivalvia: Unionida) and an evaluation of mitigation strategies. We found that drought studies were concentrated mostly in the USA, with a focus on the Unionidae family. Topics ranged from the physiological effects of high temperatures, emersion, and hypoxia/anoxia to behavioural and reproductive consequences of drought and the implications for biotic interactions and ecosystem services. Studies spanned all levels of biological organization, from individual responses to population- and community-level impacts and ecosystem-wide effects. We identified several knowledge gaps, including a paucity of trait-based evaluation of drought consequences, limited understanding of thermal and desiccation tolerance at the species level, and the synergistic effects of multiple drought stressors on mussels. Although we found many studies provided suggestions concerning management of populations, habitat conditions, and anthropogenic water use, a systematic approach and testing of recommended mitigation strategies is largely lacking, creating challenges for managers aiming to conserve freshwater mussel communities and populations in light of climate change.

Climate cycling did not affect haplotype distribution in an abundant Southern African avian habitat generalist species, the familiar chat (Oenanthe familiaris).

Avian species diversity in Southern Africa is remarkably high, yet the mechanisms responsible for that diversity are poorly understood. While this is particularly true with respect to species endemic to the subregion, it is unclear as to how more broadly distributed African species may have colonized southern Africa. One process that may in part account for the high bird species diversity in southern Africa is a "species pump" model, wherein the region was repeatedly colonized by lineages from areas further north: a pattern related to climate cycling and the eastern African arid corridor. Once occupying southern Africa, with its many varied biomes, it is possible that climate cycling further affected lineages by generating genetic diversity in multiple refugia, a pattern recently shown for several southern African bird species. Here, we used mtDNA to address these questions in a widespread, sedentary habitat generalist bird species, the familiar chat (Oenanthe familiaris). The phylogenetic structure suggests a north-to-south colonization pattern, supporting the "species pump" model. Haplotype diversity was partitioned into two distinct clusters: southern Africa and Malawi (East Africa). Southern African haplotypes were not geographically partitioned, and we hypothesize that this pattern has arisen because this species is a habitat generalist, and as such resilient to habitat-altering climate perturbations. Based on our phylogenetic results, we discuss the validity of currently recognized subspecies.

Hibernation nest site selection but not overwinter activity is associated with microclimatic conditions in a hibernating mammal

Fine-scale variation in microclimates between habitats may impact energy consumption for the organisms that inhabit them. This may be particularly important for sedentary species or those unable to change habitats for long periods, such as hibernators. Low ambient temperatures were traditionally thought key to microclimatic selection for hibernation locations, but recent research suggests that other factors may contribute or exceed ambient temperature in importance. We aimed to characterise microclimates at hibernacula of wild hibernating hazel dormice Muscardinus avellanarius, and test how these microclimates differ to those at locations without hibernacula using a microclimatic modelling approach. Dormice hibernated in areas with warmer soil temperatures and lower variability in humidity and relative shortwave radiation. These results add to the growing body of evidence that low ambient temperatures may not be the primary driver of hibernation microclimate selection, although temperature is still likely to play an important role. We also found that ambient temperatures measured at the microclimatic level were substantially buffered compared to point samples taken at the nearest weather station (∼1.6 km away), highlighting the importance of considering microclimates in wildlife conservation in the face of future environmental change.

Beneath the lens: Exploring the impacts of underwater photographers in marine-based tourism

As scuba diving proliferates in popularity as a nature-based recreational activity, the associated benefits and impacts are correspondingly emerging. Previous studies showed that underwater photographers are potentially the more impactful group of scuba divers. To further explore the impacts and behaviour of underwater photographers, this study attempted to predict their impacts through three photography-related variables, including species of interest, photography habit, and photography commitment through a case study in Hong Kong. A scuba diver survey was performed in summer 2021 to assess the impacts of divers, a follow-up questionnaire survey was delivered, and a total of 106 samples were collected. Findings showed that underwater photographers caused more negative impacts than ordinary scuba divers. Among underwater photographers, individuals more interested in conspicuous and actively moving species have more frequent contact with marine organisms. In contrast, those more interested in cryptic and sedentary species were more likely to cause intentional contact. Underwater photographers with greater commitment also showed more frequent and more intentional connections. Implications were drawn regarding underwater photographers' behaviors, and relevant suggestions were recommended to address the potential concerns. Management implicationThis study highlights the significant ecological impacts of underwater photographers who cause higher contact rates with the coral community, which causes more severe damage. The research suggested various policies for the protected areas managers to mitigate the advert ecological impacts from the recreational divers as follows:●Train underwater photographers on proper techniques to reduce ecological impact.●Regulate the use of professional photography devices in marine environments.●Implement comprehensive pre-dive briefings to promote eco-friendly diving practices.●Use supervised dives to ensure adherence to environmental guidelines.By adopting the above measurements, the marine ecosystem can be protected, which can promote sustainable tourism practices.

Reactions of wintering passerines to male calls of the European cuckoo Cuculus canorus

The reaction of birds to the nest parasite, the European cuckoo Cuculus canorus, has been the subject of extensive testing in various aspects. However, while the cuckoo is a long-distance migrant, some of its hosts are sedentary species. In this study, we aimed to investigate whether species, primarily hosts, react to the presence of the cuckoo also in the winter season. This behaviour may involve an attempt to drive the parasite away from locations that will subsequently become their breeding sites. During playback experiments conducted in the winter of 2021/2022 in Poland, we demonstrated that numerous bird species react to the male cuckoo calls in winter. These calls may be perceived as a source of danger, particularly by cuckoo hosts, who responded to this call more frequently than non-hosts and the control species (pigeon). Nonetheless, the birds’ reactions were not strong, as they did not approach the source of the call. However, our results are constrained by the limited number of cuckoo host species wintering in Poland. To better evaluate the intensity of bird responses to the male cuckoo’s call during the non-breeding season, further studies should be conducted in regions where a greater variety of species, especially those most susceptible to parasitism, overwinter.

Spatial population genetic structure of Caquetaia kraussii (Steindachner, 1878) evidenced by species-specific microsatellite loci in the middle and low basin of the Cauca River, Colombia.

The adaptative responses and divergent evolution shown in the environments habited by the Cichlidae family allow to understand different biological properties, including fish genetic diversity and structure studies. In a zone that has been historically submitted to different anthropogenic pressures, this study assessed the genetic diversity and population structure of cichlid Caquetaia kraussii, a sedentary species with parental care that has a significant ecological role for its contribution to redistribution and maintenance of sedimentologic processes in its distribution area. This study developed de novo 16 highly polymorphic species-specific microsatellite loci that allowed the estimation of the genetic diversity and differentiation in 319 individuals from natural populations in the area influenced by the Ituango hydroelectric project in the Colombian Cauca River. Caquetaia kraussii exhibits high genetic diversity levels (Ho: 0.562-0.885; He: 0.583-0.884) in relation to the average neotropical cichlids and a three group-spatial structure: two natural groups upstream and downstream the Nechí River mouth, and one group of individuals with high relatedness degree, possibly independently formed by founder effect in the dam zone. The three genetic groups show recent bottlenecks, but only the two natural groups have effective population size that suggest their long-term permanence. The information generated is relevant not only for management programs and species conservation purposes, but also for broadening the available knowledge on the factors influencing neotropical cichlids population genetics.

Impacts of noise pollution from high-speed rail and road on bird diversity: a case study in a protected area of Italy

The disturbance of infrastructures may affect biological communities that are exposed to them. This study assesses the impact of high-speed (highway and railway) infrastructures in a protected study site, the Natural Reserve Fontanili di Corte Valle Re (Emilia–Romagna, Italy). We compared bird diversity with sound intensity and frequency in three sampling areas, increasingly distant from the infrastructures at the border with the reserve, during the last 4 years (2019–2022), monitoring sedentary, nesting, and migratory bird species. We hypothesize a decreasing diversity closer to the source of disturbance, which is mostly attributable to noise pollution. Our findings confirmed this trend, and we show that, in particular, disturbance seems to influence species richness more than the total abundance of birds. We also discovered that highway disturbance was much higher than railway in terms of frequency and duration. In light of these results, we suggest that some species, which have a behavioral ecology strongly based on singing to communicate with each other for their reproductive and defensive strategies, may suffer more from constant acoustic disturbance. The installation of effective noise barriers to shield the sound produced by the highways should be considered a mandatory request not only in proximity to houses but also in the vicinity of protected areas.

Functional activity of the blood system of two migratory species of the Ural

The presented data on the study of the functional activity of the blood system of migratory species of the fauna of the Urals: Vespertilio murinus [Linnaeus, 1758], and Pipistrellus nathusii Keyserling et [Blasius, 1839]. Multivariate nonparametric analysis of variance of red blood parameters (p 0.05) of migrating bats and the sedentary pond bat showed significant species differences. In bats, a certain genetically determined multidirectionality in the mobilization of emergency regulation mechanisms of the lymphoid blood system of sedentary and migratory species has been noted.

Movements and spatial distribution of an endangered fish (Sciaena umbra) within a marine protected area

The brown meagre (Sciaena umbra) is an endangered species, which requires specific protection measures to ensure its conservation. These measures need to be informed by high-quality scientific knowledge on their space use patterns. Here, we used acoustic telemetry to assess its seasonal movement patterns and habitat use within a marine protected area (MPA). Our results suggested that S. umbra is a highly sedentary species (home range < 1.0 km2) and, therefore, the MPA is extensive enough to protect the local population. Their population was discretely distributed in two main areas within the MPA, which was likely a result of habitat segregation and density-dependent movements. The temporal variability of their movements further uncovered when and where spawning occurs (mainly, but probably not only, in the fully protected area in June) and indicated that spillover of this species is limited but still possible. Overall, we highlight the importance of MPAs in the recovery of S. umbra, we advocate the need to perpetuate the current national fishing bans and extend it to other countries in the Mediterranean region, and we emphasize that considering the fine-scale movements of S. umbra in future management actions is key to achieving a successful recovery of their populations.

Recent increasing homogenisation in Austrian butterfly communities over the past decades

In Europe, abundance, biomass and species richness of many insect taxa declined during the last decades. This decline might be accompanied by long‐term temporal changes in community composition and dominance orders. Here, we use the data base of the natural history museum of Salzburg based on museum records and field books on Austrian butterflies covering the years 1945–2018 and asked 1) whether and how community composition of important butterfly guilds changed and 2) whether these changes are in accordance with reciprocal shifts in species abundances leading to increased functional stability. In comparisons of annual changes in dominance orders, we found an increasing tendency of compositional stability of dominant species. The trend was most pronounced in generalist and dispersive species, while dominant grassland, xerothermophilic and sedentary species tended to decrease in relative abundance. We also demonstrate a temporal trend towards increasing regional stability in relative abundance rank orders. We did not find compelling evidence for reciprocal shifts in abundances of dominant and subdominant species of the same guild and of asynchronous population fluctuations as required by models that link abundance compensation and functional stability. Our study highlights the ongoing trend towards faunal homogenisation at regional spatial scales in the European Alps.

Near or far: revision of distribution, breeding and winter ranges of two sibling Pipistrellus species (Chiroptera, Vespertilionidae) in Eastern Europe and the Caucasus

Abstract Knowledge of species distribution and, for migratory species, seasonal occurrence is particularly important for vulnerable and protected animals such as bats. The former European bat species Pipistrellus pipistrellus was split into two, Pipistrelus pipistrellus s.s. and Pipistrelus pygmaeus, over 20 years ago. However, their distribution, breeding and winter ranges as well as migratory status in Eastern Europe and the Caucasus remained obscure. In our study, we scrutinised records of both species and assessed the sex ratio during their breeding season in this region. We show that Pipistrellus pipistrellus s.s. has a significantly smaller range than previously assumed, being restricted to the southern part of the study area. On the contrary, Pipistrelus pygmaeus has a broader distribution, covering the Caucasus and Eastern Europe, up to ca. 59° N. Hence, all historical records and long‐distance movements of Pipistrellus pipistrellus sensu lato from Eastern Europe within the inferred allopatric occurrence of Pipistrelus pygmaeus should be attributed to Pipistrelus pygmaeus. The high portion of adult males in breeding localities, mass wintering within the breeding range and lacking evidence of long‐distance seasonal movements imply that Pipistrellus pipistrellus s.s. is a sedentary species. In Pipistrelus pygmaeus, the sex ratio among adults during the breeding season varies latitudinally. The female‐biased sex ratio, absence of mass wintering and the historical long‐distance recoveries of ringed individuals suggest that this species is migratory in Eastern Europe. The male‐biased sex ratio during the breeding season, along with late autumn records, suggests that the Caucasus represents its winter range.

Avian responses to an extreme weather event: The case of the ‘Filomena’ snowstorm in Madrid (central Spain)

Cold spells and severe weather may have detrimental effects in wild birds, but owing to the stochastic nature of these events, it is not always possible to measure their impacts. In January 2021, a strong snowstorm known as ‘Filomena’ affected Spain, mainly the region of Madrid (Central Spain), which was fully covered with snow and suffered freezing temperatures for a fortnight. Using bird surveys conducted in the winter-spring of 2020 and 2021 (before and after Filomena) at same locations, we addressed the possible impact of the cold spell in three widespread gamebirds: Wood Pigeon (Columba palumbus), Eurasian Magpie (Pica pica) and Red-legged Partridge (Alectoris rufa). No significant abundance differences were found between years for none of the species and hunting pressure was only significantly reduced for Partridges, hence this species may have been negatively affected by Filomena. Results suggest that in response to Filomena, Pigeons conducted partial migration in search of better conditions, while Magpies aggregated in certain areas of Madrid and Partridges endured the harsh conditions within their home ranges. Our results highlight the importance to alleviate negative impacts of extreme weather events in wild birds through management actions, especially for sedentary species.

Algunos aspectos estructurales y ecológicos de la ictiofauna del Sistema de Iberá (Corrientes, Argentina)

The present paper deals with the structure, distribution and main ecological characteristics of the fish fauna in the wide complex of lenitic water bodies within the Iberá system, at Corrientes Province, Argentina.&#x0D; In the waters of such basin -which covers nearly 1,200,000 ha- were recorded 81 species of fishes, of 59 genera, 19 families and 8 orders. The basic structure of the fish fauna was given by sedentary species (it is: species able to thrive and reproduce in lenitic waters) that are exclusive in the northern area of the system, while only two typical migratory fishes: Prochilodus platensis and Salminus maxillosus, were present at the Southern area (more under the influence of the Corrientes River).&#x0D; The fish productivity is very poor from the economical point of view, particularly at the northern area, being in the higher trophic level fishes of low value, such as Hoplias malabaricus and Hoplerythrinus unitaeniatus (“tarariras”), Acestrorhamphus jenynsi and Acestrorhynchus falcatus (“dientudos”), and more frequently Serrasalmus nattereri and S. spilopleura ("pirañas”).&#x0D; This particular situation is due to the actual high concentration of organic matter derived from the exuberant aquatic vegetation. It is possible that the Iberá system had played in the past, in an environment of large open pools, a very important role in the fish productivity of the regional waters.

Bird’s Consortium Ties with Parthenocissus inserta (A. Kern.) Fritsch., 1922 on the Example of Forest Parks and City Phytocenoses in Kyiv City (Ukraine)

Abstract Parthenocissus inserta (A. Kern.) Fritsch. adapts to living in the forests of Ukraine. The influence of P. inserta on native species and its consortial ties with representatives of the secondary ranges biota, in particular birds, has not been studied. The purpose of this study is to make an inventory of the consorts’ ornithocomplexes of P. inserta, to give a comparative analysis of topic and trophic consorts as a result of an introduced species’ participation in the transformation of habitat’s conditions. The material was collected from 2019 to 2022 in forest parks and urban green spaces of the Kyiv city. The bird distribution was determined by the standard method of counting birds at points. Exactly 12.2 ha of P. inserta plantations were surveyed. Trophic consortium relationships of P. inserta with 32 bird species and topic ones with six bird species were revealed. The species composition of consorts was higher in forest fragments than in urban plantations (26 and 21 species, respectively). In the ornithocomplexes of P. inserta consorts in forest biotopes, there was a smaller pressure of dominant species and a more evenly ranked distribution of species by abundance than in urbanized ones. The similarity of the consort’s species composition in urbanized and natural biotopes according to the Sorensen index was 0.64, in consorts 1 and 2 of the consortium concentres was 0.32, and in topic and trophic consorts was 0.27. According to the status of stay in the region, trophic consorts of P. inserta were mainly resident birds – 20 species (62.50%), wintering birds – six species (18.75%), and birds migrating through the region – six species of birds (18.75%). Among the topic consorts, there were four species of sedentary species and two species arriving for nesting. Principal component analysis revealed the largest positive relationship between P. inserta planting area and the number of consort bird species nesting (0.999) and feeding (0.889) on girlish vine plants. We predict that in the future, P. inserta will be more strongly woven into the matter cycle of the secondary range ecosystems. The study of consortial relationships between invasive plants and birds, taking into account the knowledge of the ecological characteristics of consort birds, will make it possible to more effectively prevent the spread of plants into natural biotopes.

Unraveling trait‐based fish community assembly in tropical reservoirs

AbstractDamming of large rivers has promoted well‐documented ecosystem changes that constitute critical threats to freshwater fish biodiversity. However, it is unclear how trait–environment relationships drive community assembly in older (&gt;50 years) tropical river‐reservoir systems. We assessed physical features filtering functional traits (RLQ and fourth‐corner approaches) in seven tropical reservoirs along a major river, in southeastern Brazil, and correlated taxonomic and functional counterparts of local and beta diversity to assess niche‐based assembly processes under prevailing environmental conditions (null model approach). Lower littoral habitat availability (smaller area, volume, and riverine influence) favored species inhabiting open areas that feed on the bottom (mostly migratory species). Downstream position (lower elevation and inflow of water from the mainstem) allowed migrators to enter the reservoirs and promoted environmental heterogeneity, favoring detritivores, invertivores, and carnivorous generalists. Total blocking of the main channel excluded most migratory species from reservoirs at upstream reaches, whereas higher riverine influence and hydrological stability (larger area, volume, and water residence time) favored small‐sized sedentary species (omnivores and piscivores with parental care, mostly non‐native species) in the littoral zone. Correlations differing from null expectations for alpha diversity and nestedness revealed that niche‐based processes support species richness and loss under higher riverine influence and hydrological stability. Our study supports the importance of physical features to set functional spaces available for fish species, but random processes that boost taxonomic differences between reservoirs, largely related to non‐native species introductions, are the primary drivers of fish assemblage structure in tropical reservoirs long‐term disconnected from riverine dynamics.

Historical navigation routes in European waters leave their footprint on the contemporary seascape genetics of a colonial urochordate

Humans have intensively sailed the Mediterranean and European Atlantic waters throughout history, from the upper Paleolithic until today and centuries of human seafaring have established complex coastal and cross-seas navigation networks. Historical literature revealed three major long-lasting maritime routes (eastern, western, northern) with four commencing locations (Alexandria, Venice, Genoa, Gibraltar) and a fourth route (circum-Italian) that connected between them. Due to oceangoing and technological constraints, most voyages were coastal, lasted weeks to months, with extended resting periods, allowing the development of fouling organisms on ship hulls. One of the abiding travellers in maritime routes is the colonial ascidian Botryllus schlosseri already known since the eighteenth century in European and Mediterranean ports. This species, was almost certainly one of the common hull fouling travellers in all trade routes for centuries. Employing COI haplotypes (1008 samples) and microsatellite alleles (995 samples) on colonies sampled from 64 pan-European sites, present-day Botryllus populations in the Mediterranean Sea/European Atlantic revealed significant segregation between all four maritime routes with a conspicuous partition of the northern route. These results reveal that past anthropogenic transports of sedentary marine species throughout millennia long seafaring have left their footprint on contemporary seascape genetics of marine organisms.