Dispersal Movements Research Articles

First insights in terrestrial mammals monitoring in the Candelaria and Machay Reserves in the Ecuadorian Tropical Andes.

Habitat disturbance leads to biodiversity decline and modifications in the landscape structure and composition, affecting both dispersal movements and ecological processes at different temporal and spatial scales. The Ecuadorian Tropical Andes harbour suitable habitats for the distribution of a wide variety of species; however, there is a lack of studies focused on mammal diversity and its association with the habitat attributes in the central-eastern slopes. Here, we reported the diversity of terrestrial mammals recorded between 2019 and 2021 in a camera-trap monitoring study in the Candelaria and Machay reserves in the upper basin of the Pastaza River, Ecuador. We performed site-occupancy probability analysis to assess the influence of spatial variables in the species' occurrence and also, based on natural marks, we reported preliminary findings in Andean bear individual identification. We detected 22 species of terrestrial mammals. Alpha diversity was similar between reserves with slightly higher species richness in Machay. Evenness indices showed unequal species distribution, with the Andean bear and domestic dogs exhibiting greater dominance. In addition, species composition was dissimilar between reserves, where the species turnover mostly explained the beta diversity. We observed that Andean bear and puma detections increased according to the natural vegetation cover. Conversely, domestic dogs were frequently detected in cells with an increasing proportion of pastures and crops. Additionally, we identified 26 Andean bears and six individuals recaptured during our study. Our results caution about the disturbance derived from human activities since we recorded unprecedented detections of domestic dogs in wild habitats. Nonetheless, it highlights the importance of private conservation areas (e.g. Candelaria, Machay and others) for supporting the occurrence and dispersal of terrestrial mammal species between larger areas in the upper basin of the Pastaza River.

Dispfit: An R package to estimate species dispersal kernels

Dispersal of organisms is a ubiquitous aspect of the natural world, with wide implications across scales and organization levels. Interest in dispersal has risen sharply over the past 30 years, mostly due to the multiple and rapid global changes ecosystems face. Among the various aspects that may characterize a dispersion event, dispersal distance is considered a key descriptor in a wide variety of studies across taxonomic groups. Typically, dispersal distances are defined in the form of dispersal kernels describing the dispersal distance distribution according to probability density functions. Although numerous methods providing dispersal data exist, there is still a lack of intuitive and comprehensive approaches and tools to estimate dispersal kernels from such data. Here we present the dispfit package, an R software application developed to fill this gap. dispfit fits and compares different families of parameterized functions to describe and predict dispersal distances. It includes 9 well-known and commonly used distributions, computes goodness-of-fit and model selection statistics, and estimate each distribution's parameters, along with their first four moments (mean, standard deviation, skewness, and kurtosis). We describe the main functions included in dispfit and provide an example to illustrate the workflow of the typical analyses performed within the package. We believe that dispfit will critically contribute to improving the modelling of species' dispersal distances, thus enhancing the understanding of the ecological and evolutionary processes involving dispersal movement.

Estimating the onset of natal dispersal for a large diurnal raptor: A methodological comparison

We estimated the onset of natal dispersal for a large diurnal raptor with high propensity towards large-scaled exploratory movements during the post-fledging period, the White-tailed Sea Eagle (Haliaeetus albicilla). We analysed GPS tracking data of 21 juveniles with respect to the onset of natal dispersal comparing six methods available from the recent literature. While none of the methods significantly differed from the visual method, the Distance Threshold method underestimated the dispersal onset for some individuals. Likewise, coefficient of variation methods overestimated the dispersal onset in few cases, presumably because the temporal scale of available GPS fixes did not correspond to the scale of discrete dispersal movements. We conclude that all tested methods are generally suitable to estimate the dispersal onset, specifically if the research question does not depend on an exact but rather a rough estimate. A visual determination might increase flexibility to account for individual behavior and yields consistent results across individuals, but highly reduces the comparability across observers and studies. For research questions relying on exact estimates, we propose using a combination of an automated method and a visual determination as a back-up method for single individuals with clear under- or overestimation. An exploratory comparison showed that the temporal resolution of the GPS may further affect the accuracy of natal dispersal estimates. For individuals with clear movement patterns, high-resolution movement data could increase the accuracy of Coefficient of Variation methods. We underline the necessity for further investigation on the effects of temporal resolution on dispersal onset estimates.

Movement ecology of exotic nilgai antelope: A threat to the re‐emergence of cattle fever ticks in the southern USA

AbstractWildlife plays an important role in the emergence of livestock diseases, and their movements can complicate disease management efforts. One of the most significant vector‐borne diseases of livestock worldwide is bovine babesiosis, spread by cattle fever ticks (CFTs; Rhipicephalus [=Boophilus] microplus and Rhipicephalus [=Boophilus] annulatus). Although CFTs were eradicated from the United States by 1943, bovine babesiosis and CFTs are prevalent in México. Recently, management of CFTs in the Texas–México region has been complicated by the presence of free‐ranging, exotic nilgai antelope (Boselaphus tragocamelus). Nilgai are abundant in this region and are competent hosts for CFTs. The goal of this study was to better understand nilgai movements and space use to inform CFT treatment strategies. We analyzed hourly locations from 40 GPS‐collared nilgai in Cameron County, TX, USA, from April 2019 to September 2020. We assigned each nilgai a movement behavior using the net squared displacement metric. We estimated nilgai home range sizes at different temporal scales (monthly, seasonally, and overall) using Brownian bridge movement models. We observed movement patterns consistent with residency (52.5%), seasonal movers (17.5%), dispersal (5%), and unclassified (25%). Resident nilgai had an average maximum axial distance of 7.8 km, while two young females made separate dispersal movements of about 40 km within a year. Overall, nilgai had large and highly variable home ranges: annual median home range estimate for females was 563 ha (range = 105–1545 ha), and for males, it was 937 ha (range = 221–1602 ha). Peak nilgai movements occurred during crepuscular hours, and median hourly movement for females was 57 m/h, and for males, it was 66 m/h. Nilgai home ranges and long‐distance movements have the potential to overlap multiple ranches, as the typical ranch size in South Texas ranges from 250 to 6000 ha. Resident nilgai were more likely to maintain local infestations of CFT. Dispersal events took place during peak tick season, demonstrating the potential for nilgai to aid in the spread of CFT. Understanding these behaviors will help the CFT Eradication Program develop more efficacious treatment strategies to treat infestations in nilgai.

Survival, Dispersal and Initial Migratory Movements of Juvenile Great Spotted Cuckoos Clamator glandarius

El críalo europeo Clamator glandarius es un ave perteneciente a la familia Cuculidae cuya biología se ha estudiado intensamente durante años, sobre todo en el contexto del parasitismo de cría. Sin embargo, todavía existen importantes lagunas en el conocimiento de la biología de esta especie. Estudios recientes han puesto de manifiesto la ausencia de información sobre la supervivencia, la dispersión y las rutas migratorias en los juveniles de esta especie, por lo que el objetivo principal de este estudio es contribuir a llenar este vacío. Para ello, utilizamos radiotransmisores y emisores satélite tipo PTT para estudiar tanto los primeros movimientos en el área de cría, así como los movimientos migratorios de larga distancia de los juveniles de críalo europeo, respectivamente. Comprobamos que una parte importante de los individuos marcados murieron en el área de cría pocos días después de abandonar el nido, con evidencias directas e indirectas que apuntan a la depredación como la principal causa de mortalidad. Nuestros resultados sugieren que los movimientos premigratorios de los juveniles (es decir, los movimientos realizados antes de abandonar la península ibérica) son relativamente diferentes a los encontrados anteriormente para los adultos de esta especie. La elevada tasa de depredación impidió que la mayoría de los cucos juveniles llegaran a su zona de invernada en el África subsahariana, y sólo 3 de los 13 individuos marcados por satélite lograron abandonar la zona de cría y se desplazaron a África utilizando la ruta del Atlántico oriental. En general, la información proporcionada por nuestro trabajo contribuye a una mejor comprensión de la biología de los juveniles de esta especie y podría ser útil para abordar los posibles problemas de conservación a los que pueda enfrentarse en el futuro.—Martínez-Zunzarren, N., Ruiz-Raya, F., Pérez-Contreras, T., Soler, M. e Ibáñez-Álamo, J.D. (2023). Supervivencia, dispersión y movimientos migratorios iniciales de los juveniles de críalo europeo Clamator glandarius. Ardeola, 70: 59-74.

Latin American aquatic mammals: an overview of 12 years focusing on molecular techniques applied to conservation

Ecological information useful for conservation purposes have benefitted from recent and rapid advancements in genetic techniques, revealing unknown aspects of behavior, natural history, population structure and demography of several aquatic mammal species, many of them with conservation concerns. Molecular markers have been used to define management units, to settle taxonomic uncertainties, to control illegal wildlife trade, among others, providing valuable information to decision-making to conserve and manage aquatic mammals. We review genetic studies applied to conservation-related issues involving natural populations of more than 40 species of aquatic mammals in Latin America, covering four taxonomic groups. The main goal was to assess which genetic approaches have been used and to identify gaps in genetic research relating to geographic areas and species. We reviewed studies published in peer-reviewed journals between 2011 and 2022, and found that most were focused on population structure, phylogeography, gene flow and dispersal movements. The review revealed that researchers need to increase and improve the knowledge in those species which face major conservation concern. Scarce findings were related to forensics and its application to wildlife trade. In the era of next-generation-sequencing techniques, just a few studies used genomics as a tool for monitoring gene diversity, an important goal to help us predict how species will cope with climate change events. Looking to the future we suggest which species, geographic areas and genetic studies should be prioritized in a scenario of climate change and increased human threats (e.g., fishery bycatch, habitat degradation, etc.) and the urgent need for conservation actions. Finally, we highlight the benefits of the collaborative works and the necessity of generating a conservation genetic network, with an open agenda to discuss the local and regional problematics. All in all, we strongly emphasize the generation of critical information towards the effective conservation and management of aquatic mammals in Latin America.

Integrating Habitat Availability, Permeability, and Configuration in a Model of Landscape Connectivity: The Contribution of Habitat's Site-to-Site.

The landscape configuration, the permeability of the matrix and the possibility of random dispersal movement of species are essential to robust modeling of the landscape connectivity. To represent this condition, we report a spatial model that integrates graph theory, circuit theory, metrics of habitat availability and includes a temporal aspect by looking into land use changes over time. We identify the possibilities of movement of species site-to-site over time in the landscape, taking into account not only the importance of sites of focal habitats, but also the potential relevance of the matrix for landscape connectivity. The modeling was applied to two rural landscapes, considering three functional groups of mammals with different resource-feeding and habitat requirements. The model indicated multiple and new dispersal non-linear potential routes to each group of mammals, considering its specific requirement to obtain resources and its movement pattern on the agricultural matrix.

Dispersal Movements and Hot Spot Areas of Juvenile Bonelli’s Eagles on the Island of Crete, Greece

The Bonelli’s Eagle (Aquila fasciata) is the main avian predator in almost all the islands of the Greek archipelagos. The phase of its natal dispersal has never been studied in Greece, though it constitutes a crucial part of the species ecology and conservation. In an effort to investigate the movement patterns and settlement areas of young eagles, we tagged 30 fledglings on the island of Crete during 2019–2023 with GPS/GSM transmitters. Fledging date was set the first day with full satellite coverage and consecutive GPS fixes for individual birds while the initiation of the dispersal period was established when they performed consecutive long flights, overstaying away from their natal territory (>10 km). Mean fledgling date was calculated at May 27 (range = 20/5–8/6), whereas the dispersal period started on average on September 03 (range = 30/8–21/9), namely ca. 90–100 days after the abandonment of the nest. All juvenile birds wandered around over the entire island residing primarily in two distinct habitat types i.e. coastal cliffs and satellite islets around Crete and agricultural areas in the lowlands covered with olive groves and vineyards. Preliminary surveys show that the juvenile birds avoid active Bonelli’s Eagle territories and select rural areas near landfills, water reservoirs, fowl pens, and uninhabited islets, specializing on prey species that are readily available (i.e. gulls, corvids, rock pigeons, wild rabbits and poultry). This fact makes them particularly susceptible to human-induced mortality such as electrocution, drowning in open water tanks and poaching, which accounted for ca. 60% of the casualties of this age group. Overall, the study confirms that land use changes and human pressure are the major threats for the species on Crete, likewise in the rest of its distribution range in the Mediterranean.

Database records of koalas (Phascolarctos cinereus) in northern Sydney

This study examined records of koalas (Phascolarctos cinereus) in northern Sydney held in online biodiversity databases. There were 221 unique records distributed across the Northern Beaches, Ku-ring-gai, Hornsby and Hills Shire local government areas from 1788 to 2022, with records from the Northern Beaches local government area comprising 68% of this dataset. Records from the 1970s represented 41% of the dataset (90 records), while there were only 42 records from 2000 to 2022. Post-2000 records were spread broadly, showing no major contraction in distribution compared to the spread of earlier records, but with a notable absence of more recent records on the Barrenjoey Peninsula, a previously documented species stronghold. Substantial proportions of records were found in both protected reserves and privately-owned lands, which alludes to the value of the former but also shows that koala conservation in this capital city cannot rely solely on protected reserves. The 2000–22 records were widely distributed across 15 plant community types and areas of non-native vegetation, probably reflecting breeding and dispersal movements more than specific habitat selection. Possibly due to the same influences, none of the 2000–22 records were matched to areas represented by the Koala Habitat Suitability Model, a prediction model for spatial distribution of potential koala habitat across NSW, with a high habitat suitability score (greater than 0.85). We therefore recommend systematic on-ground surveys to clarify the patterns observed from the records.

Natal Dispersal and Seasonal Migration of White-Tailed Sea Eagles in Khabarovsk Krai (Russia) and Hokkaido (Japan)

White-Tailed Sea Eagles (Haliaeetus albicilla) become sexually mature at 5–6 years and the conditions of habitats and flight paths for local and seasonal movements in the nomadic period between post-fledging and breeding territory occupation are important in terms of population demographic relevance. The purpose of this study is to elucidate post-fledging movements, seasonal migrations, and habitats of immature White-Tailed Sea Eagles by GPS tracking. GPS transmitters were attached to nestlings of White-Tailed Sea Eagles at the middle basin of Amur River (around Slavyanka; 49°50'N, 136°76'E) and Lake Chukchagir (51°59'N, 136°36'E) in Khabarovsk Krai, Russia, and at Abashiri (44°1'N, 144°16'E) in eastern Hokkaido, Japan, in the breeding seasons of 2017–2022. Habitats used by GPS-tagged immatures were investigated with satellite images and field observations. The dispersion of post-fledging sea eagles from their natal nests occurred in autumn (September–October) for both sites in Khabarovsk and Abashiri. The first destinations in dispersal movements were river tributaries or lakes in floodplains in Khabarovsk (n=4) and rivers in Abashiri (n=2). Start timing and the first destination of emigration from natal sites for both breeding areas was considered to be related with upstreaming of salmonid fish for spawning. All of three juveniles fledged in Khabarovsk and tracked at least until their first winter wintered at the coastal area of Primorsky Krai, Russia, approximately 800–1,000 km south of their birthplaces, however, one juvenile took a different migration route to the wintering ground than the other two. Besides, two eagles tracked for more than two years after their birth in Khabarovsk showed the same migration routes in spring and autumn, and in the first year and subsequent years, respectively. Meanwhile, juvenile eagles fledged in Abashiri (n=2) moved to the places up to about 150 km south of their natal sites in their first winter, despite the fact that some major wintering grounds for sea eagles exist around their birthplace. Previous study reported that some colour-ringed immature White-Tailed Sea Eagles fledged at nests in Nemuro (43°19'N, 145°35'E), located approximately 100 km southeast direction of Abashiri, had been observed around their birthplaces in winter (Shiraki, 2002). Not only food availability but also genetic factor may be involved in determination of the wintering area. White-Tailed Sea Eagles over one year old from the nests in Khabarovsk (n=2) and in Abashiri (n=1) visited the vicinity of their natal sites during spring and summer. As White-Tailed Sea Eagles are known to have a tendency to nest in the natal area, young eagles might assess breeding opportunities around their natal sites. Immature White-Tailed Sea Eagles with GPS mostly stayed at habitats with food supplied from human activities, such as small fish discarded in fishery, marine waste, Sika Deer (Cervus nippon) residue left behind after hunting or killed in collisions with vehicles or trains, during winter in both of Primorsky and Hokkaido.

High strength and deformation stability achieved in CrCoNi alloy containing deformable oxides

• The spreading lattice distortion in CrCoNi-O high entropy solution locally relieved the severe interfacial mismatch and led to nanoscale variation of interfacial strain at the matrix-oxide interface. • Dislocations slip transferred from solid solution phase to ceramic phase, enabling the ceramic phase with significant deformability. • The yield strength of the dual-phase samples was twice of the single-phase CrCoNi-O alloy; strong strain hardening was obtained with ultra-high deformation stability, whereas the single-phase CrCoNi-O sample exhibited catastrophic shear localization. Hard secondary phases usually strengthen alloys at the expense of ductility. In this work, we made a dual-phase CrCoNi-O alloy containing a face centered cubic matrix and chromium oxide. On one side, the dispersed chromium oxide nano-particles impeded dislocation movement and increased the strength of the alloy. On another side, the spreading lattice distortion in CrCoNi-O high entropy solution locally relieved the severe interfacial mismatch and led to nanoscale variation of interfacial strain at the matrix-oxide interface, which facilitated dislocations’ transmission from one phase to another. Consequently, unlike the strong but brittle oxide nanoparticles used before, the oxide phase here can afford significant dislocation activities during material's plastic deformation. Comparing the mechanical properties of CrCoNi-O alloys with and without chromium oxide particles, it was found that the yield strength of the dual-phase samples was twice of the single phase CrCoNi-O alloy and strong strain hardening was obtained with ultra-high deformation stability. High density of nanotwins formed in dual-phase samples under high stress, resulting in significant strain hardening according to the well-known twinning-induced plasticity (TWIP) effect. Our results shed light on optimizing the combination of strength and plasticity of compounds by modulating the variation of interfacial strain field based on the spreading lattice distortion.

Natal Dispersal of Eastern Imperial Eagles: Preliminary Results For the Central European Population

The Central European Population of the Eastern Imperial Eagle (Aquila heliaca) is located on its most western global distribution edge. After a strong decline in the last two centuries, the population recovered in the past decades not least due to extensive protection measurements. Conservation and scientific programs on international and national level were implemented in several countries, especially in Hungary, Slovakia, Austria, Czech Republic, and Serbia. In frame of these activities imperial eagle were tagged by satellite transmitter since 2003 in several projects by different organisations of the region. In the current presentation we show preliminary results of an analysis of the natal dispersal movements of the immature birds of this residential population of Eastern Imperial Eagles. Therefore, more than 14 million data points of more than 130 individuals were available and analysed. We defined start of natal dispersal as the point when the young birds left their natal territory (5 km from natal nest) for at least 10 consecutive days. Because of high individual variability, we decided to classify the end of dispersal manually as the time the bird became territorial for the first time. We analysed movement pattern for the whole period of natal dispersal as well as for different life stages/age classes. Therefore we distinguished between breeding (1.2–30.9) and non-breeding season (1.10–30.2) for each year of life of the birds. It turns out that daily travel ranges are higher during the breeding season than outside the breeding season and that activity decreases over the years until the birds start establishing a territory. Furthermore, we estimate utilization distribution (UD) by calculating a dynamic Brownian Bridge Movement Model (dBBMM). Therefor in a first step, a dBBMM was calculated for each single individual. Those individual UDs were summarised up by using days of tracking as weight. The resulting UD gives an overview of distribution and space use of immature Eastern Imperial Eagles. It shows that while wide explorative flights of single birds occur, the majority of the birds stays mainly in Central Europe within the range of the breeding distribution of the population. Additional, there is a connection to the western parts of Greece and the island of Crete. The results help to enhance knowledge about habitat use and identify hotspots for further conservation efforts.

Mapping the connectivity–conflict interface to inform conservation

Balancing the competing, and often conflicting, needs of people and wildlife in shared landscapes is a major challenge for conservation science and policy worldwide. Connectivity is critical for wildlife persistence, but dispersing animals may come into conflict with people, leading to severe costs for humans and animals and impeding connectivity. Thus, conflict mitigation and connectivity present an apparent dilemma for conservation. We present a framework to address this dilemma and disentangle the effects of barriers to animal movement and conflict-induced mortality of dispersers on connectivity. We extend random-walk theory to map the connectivity-conflict interface, or areas where frequent animal movement may lead to conflict and conflict in turn impedes connectivity. We illustrate this framework with the endangered Asian elephant Elephas maximus, a species that frequently disperses out of protected areas and comes into conflict with humans. We mapped expected movement across a human-dominated landscape over the short- and long-term, accounting for conflict mortality. Natural and conflict-induced mortality together reduced expected movement and connectivity among populations. Based on model validation, our conflict predictions that explicitly captured animal movement better explained observed conflict than a model that considered distribution alone. Our work highlights the interaction between connectivity and conflict and enables identification of location-specific conflict mitigation strategies that minimize losses to people, while ensuring critical wildlife movement between habitats. By predicting where animal movement and humans collide, we provide a basis to plan for broad-scale conservation and the mutual well-being of wildlife and people in shared landscapes.

Hide-and-Seek in a Highly Human-Dominated Landscape: Insights into Movement Patterns and Selection of Resting Sites of Rehabilitated Wolves (Canis lupus) in Northern Italy.

Assessing the behavioural responses of floating wolves to human presence is crucial for investigating the chance of wolf populations expanding into urbanised landscapes. We studied the movement ecology of three rehabilitated wolves in a highly human-dominated landscape (Po Plain, Italy) to explore wolf's plasticity amid widespread human pressure. To reach this aim, we estimated individual 95% utilisation distributions (UD) after the release and inspected both 95% UDs and net squared displacements to identify individual movement patterns; tested for differences in movement patterns during day and night; and analysed the selection of resting sites during dispersal movement in a highly human-altered environment. Both the 95% UDs and step lengths were smaller for wolves settling in suitable areas than for those settling in more urbanised areas. All wolves exhibited strong temporal segregation with humans during all movement phases, particularly while dispersing across highly urbanised areas. Main roads and proximity to built-up areas were shown to limit wolves' dispersal, whereas small-wooded patches that provide shelter during rest facilitated long-distance movements. This study provides important insights into wolf movement and settling in urban and peri-urban areas, providing critical knowledge to promote human-carnivore coexistence.

Standardised empirical dispersal kernels emphasise the pervasiveness of long-distance dispersal in European birds.

Dispersal is a key life-history trait for most species and is essential to ensure connectivity and gene flow between populations and facilitate population viability in variable environments. Despite the increasing importance of range shifts due to global change, dispersal has proved difficult to quantify, limiting empirical understanding of this phenotypic trait and wider synthesis. Here, we introduce a statistical framework to estimate standardised dispersal kernels from biased data. Based on this, we compare empirical dispersal kernels for European breeding birds considering age (average dispersal; natal, before first breeding; and breeding dispersal, between subsequent breeding attempts) and sex (females and males) and test whether different dispersal properties are phylogenetically conserved. We standardised and analysed data from an extensive volunteer-based bird ring-recoveries database in Europe (EURING) by accounting for biases related to different censoring thresholds in reporting between countries and to migratory movements. Then, we fitted four widely used probability density functions in a Bayesian framework to compare and provide the best statistical descriptions of the different age and sex-specific dispersal kernels for each bird species. The dispersal movements of the 234 European bird species analysed were statistically best explained by heavy-tailed kernels, meaning that while most individuals disperse over short distances, long-distance dispersal is a prevalent phenomenon in almost all bird species. The phylogenetic signal in both median and long dispersal distances estimated from the best-fitted kernel was low (Pagel's λ < 0.25), while it reached high values (Pagel's λ >0.7) when comparing dispersal distance estimates for fat-tailed dispersal kernels. As expected in birds, natal dispersal was on average 5km greater than breeding dispersal, but sex-biased dispersal was not detected. Our robust analytical framework allows sound use of widely available mark-recapture data in standardised dispersal estimates. We found strong evidence that long-distance dispersal is common among European breeding bird species and across life stages. The dispersal estimates offer a first guide to selecting appropriate dispersal kernels in range expansion studies and provide new avenues to improve our understanding of the mechanisms and rules underlying dispersal events.

Dispersal without drivers: Intrinsic and extrinsic variables have no impact on movement distances in a terrestrial amphibian.

Dispersive movements are often thought to be multicausal and driven by individual body size, sex, conspecific density, environmental variation, personality, and/or other variables. Yet such variables often do not account for most of the variation among dispersive movements in nature, leaving open the possibility that dispersion may be indeterministic. We assessed the amount of variation in 24 h movement distances that could be accounted for by potential drivers of displacement with a large empirical dataset of movement distances performed by Fowler's Toads (Anaxyrus fowleri) on the northern shore of Lake Erie at Long Point, Ontario (2002–2021, incl.). These toads are easy to sample repeatedly, can be identified individually and move parallel to the shoreline as they forage at night, potentially dispersing to new refuge sites. Using a linear mixed‐effect model that incorporated random effect terms to account for sampling variance and inter‐annual variation, we found that all potential intrinsic and extrinsic drivers of movement accounted for virtually none of the variation observed among 24 h distances moved by these animals, whether over short or large spatial scales. We examined the idea of movement personality by testing variance per individual toad and found no evidence of individuality in movement distances. We conclude that deterministic variables, whether intrinsic or extrinsic, neither can be shown to nor are necessary to drive movements in this population over all spatial scales. Stochastic, short time‐scale movements, such as daily foraging movements, can instead accumulate over time to produce large spatial‐scale movements that are dispersive in nature.

Scatter-hoarding birds disperse seeds to sites unfavorable for plant regeneration

Scatter-hoarding birds provide effective long-distance seed dispersal for plants. Transporting seeds far promotes population spread, colonization of new areas, and connectivity between populations. However, whether seeds transported over long distances are deposited in habitats favorable to plant regeneration has rarely been investigated, mainly due to methodological constraints. To investigate dispersal patterns and distances of Swiss stone pine (Pinus cembra) seeds we utilized advances in tracking technology to track the movements of their sole disperser, the spotted nutcracker (Nucifraga caryocatactes). We found routine individual movements between single seed harvesting and seed caching site. Harvesting sites of individual birds overlapped, whereas seed caching sites were separated and located on average 5.3 km away from the harvesting site. Interestingly, most distant caching sites were located at low elevations and in spruce forest, where Swiss stone pine does not naturally occur. This suggests that nutcrackers disperse seeds over long distances but that a large portion of these seeds are cached outside the known pine habitat. Therefore, we conclude that the implications of such long-distance seed dispersal movements for plant populations should be carefully considered in combination with the effects of habitat quality on plant recruitment.

Phenotypic and environmental correlates of natal dispersal movements in fragmented landscapes

ContextNatal dispersal critically influences eco-evolutionary dynamics and the persistence of spatially structured populations. As both short- and long-distance movements contribute to population persistence in fragmented landscapes, understanding dispersal requires assessing phenotypic and environmental effects on a wide range of distances.ObjectivesTo assess phenotypic and environmental correlates of dispersal movements in fragmented landscapes.MethodsWe radio-tracked juvenile middle spotted woodpeckers in fragmented landscapes to assess phenotypic and environmental effects on emigration age, transfer duration (in days), and transfer distances.ResultsLarge fledglings and those in good condition emigrated earlier than smaller individuals and those in worse condition. Birds in better condition also reduced transfer duration. Overall, females dispersed earlier, remained shorter at transfer and moved further than males. However, while females increased transfer distances with increasing connectivity, males increased distances with decreasing connectivity. Emigration age increased with decreasing patch size and increasing patch quality, and with decreasing population density in patches with soft edges. Both transfer duration and distance increased with decreasing population density.ConclusionsThe correlations between phenotypic traits of fledglings and their posterior movements suggest that early-life conditions influenced dispersal through carry-over effects. Early emigration from low-quality and high-populated patches can be a behavioural mechanism to quickly escape adverse natal conditions, but population density effects were modulated by edge hardness. Finally, because reductions in connectivity led to similar transfer distances between sexes through a reduction in female distances, a lack of sex-biased dispersal can be a previously overlooked effect of habitat isolation that may alter eco-evolutionary dynamics.

Asymptotic behavior of solutions of an ODE-PDE hybrid competition system

We study the large-time behavior of a two-species competition model in a spatially heterogeneous environment and investigate the influence of dispersal strategy on the competition. In particular, we allow one species to exhibit a random dispersal movement while the second species is constrained to a non-spatial movement dynamic. We show that there is a nonnegative threshold number (possibly equal to infinity and determined by both species' local intrinsic growth rates) such that the species adopting the random dispersal strategy persists uniformly in space if its diffusion rate is kept below this number while it goes extinct if its diffusion rate is greater than this number. Furthermore, in the critical case that the diffusing species' movement rate equals this number, exactly two scenarios are possible: the non-diffusing species wins the competition if it has a sink area; otherwise, both species coexist.

Patterns of gene flow across multiple anthropogenic infrastructures: Insights from a multi-species approach

Large-scale Transportation Infrastructures (LTIs) are among the main determinants of landscape fragmentation, with strong impacts on animal dispersal movements and metapopulation functioning. Although the detection of LTIs impacts is now facilitated by landscape genetic tools, studies are often conducted on a single species, although different species might react differently to the same obstacle. We surveyed four species (a snake, an amphibian, a butterfly and a ground-beetle) in a landscape fragmented by six LTIs: a motorway, a railway, a country road, a gas pipeline, a power line and a secondary road network. We hypothesized that LTIs carrying vehicles would mostly impact ground-dwelling species, possibly in a cumulative way. We showed that half of the overall explained genetic variability across all species was due to LTIs. While the butterfly was seemingly not impacted by any LTI, the genetic structure of the three other species was mostly influenced by roads and motorway. The power line did not affect any species and the gas pipeline only impacted gene flow in the ground-beetle through forest fragmentation, but roads systematically affected at least two species. Interestingly, we also showed that some LTIs could somehow promote gene flow, embankments probably providing favourable habitats for vertebrate species. Considering the high variability in species response to LTIs, we argue that drawing general conclusions on landscape connectivity from the study of a single species may lead to counterproductive mitigation measures and that multi-species approaches should be more systematically considered in conservation planning.