Variation In Habitat Quality Research Articles

How Does the Three‐North Shelterbelt Engineering of China Improve Its Habitat Quality? A Study of 40 Years of Change Tracking and Driving Factors

ABSTRACTThe Three‐North Shelterbelt Engineering of China (TNSEC) is a large‐scale ecological restoration project that was initiated in 1978 to enhance the ecological environment of the Three‐North Shelterbelt Engineering Region (TNSER). However, the macro long‐term data and driving mechanisms behind habitat quality in the TNSER remain inadequately understood. Therefore, multi‐source observational data, the InVEST model, and spatial analysis techniques were employed to quantify the spatiotemporal evolution of habitat quality in the TNSER since 1980. Additionally, the Optimal Parameters‐based Geographical Detector (OPGD) model was utilized to quantitatively elucidate the driving mechanisms behind changes in habitat quality. The habitat quality of TNSER has remained stable from 1980 to 2020, exhibiting significant spatial agglomeration characteristics. Areas with higher habitat quality are demonstrating a trend of expansion, while regions with poor habitat quality are experiencing fragmentation and expansion. It is anticipated that the habitat quality of TNSER will continue to remain stable in the future; however, areas with poor habitat quality and their adjacent zones are showing signs of deterioration. Changes in habitat quality within TNSER are influenced by multiple factors, primarily socio‐economic factors in nature, with GDP accounting for 55% of the variations in habitat quality. This study offers valuable recommendations for policymakers from a sustainable development perspective, highlighting the critical role of large‐scale ecological projects in enhancing environmental quality amidst ongoing ecological challenges.

The spatiotemporal evolution characteristics and influencing factors of habitat quality in the typical region of the Lunan Economic Belt: a case study of Donggang District, Rizhao.

Habitat quality is a key indicator for evaluating the biodiversity of a region. This study aims to assess the current status and characteristic changes of habitat quality in Donggang District, Rizhao while analyzing the potential factors influencing the quality of the habitat. The study employed the Integrated Valuation of Ecosystem Services and Tradeoffs Habitat Quality (InVEST-HQ) mode to assess the spatiotemporal variations in habitat quality in the Donggang District from 2008 to 2022. GeoDetector was utilized to investigate the impact of various factors on the spatial differentiation characteristics of habitat quality. The potential correlation between economic development and habitat quality was further explored using the Spearman correlation coefficient and Grayscale Association Analysis. The results reveal that habitat quality in Donggang District is highest in the east and lowest in the west, with significant correlations to land use and vegetation coverage. The study highlights a decline in habitat quality over the period, linked to rapid economic growth and industrial expansion. These insights are crucial for balancing urban biodiversity with economic development.

Environmental Drivers of Local Demography and Size Plasticity in Fire Salamanders (Salamandra salamandra).

Conspecific amphibian populations may vary widely in local demography and average body size throughout their geographical range. The environmental drivers of variation may reflect geographical gradients or local habitat quality. Among fire salamander populations (Salamandra salamandra), local demography shows a limited range of variation because high concentrations of skin toxins reduce mortality from predation to a minimum, whereas average adult body size varies significantly over a wide range. This study on four neighboring populations inhabiting the catchments of low-order streams in the upper middle Rhine Valley (Koblenz, Germany) focuses on the identification of local environmental drivers of variation in age and body size. I collected 192 individuals at two localities per stream, measured snout-vent length, clipped a toe for posterior skeletochronological age determination, and released salamanders in situ again. Populations were similar in age distribution. Local habitat quality accounted for a significant proportion of demographic variability, mediated by the impact of landscape-induced mortality risk, including roads and agriculture. Still, the main effect of variation in habitat quality was on adult body size, the result of growth rates of aquatic larvae and terrestrial juveniles. Larvae exposed to non-lethal heavy metal contamination in streams developed into smaller juveniles and adults than clean-water larvae, providing evidence for carry-over effects from one stage to another. The generally small average adult size in the Rhine Valley populations compared to those in other parts of the distribution range indicates the action of a still unidentified environmental driver.

Assessment of Habitat Quality in Arid Regions Incorporating Remote Sensing Data and Field Experiments

China’s arid regions are particularly vulnerable to the adverse effects of climate change and human activities, which pose threats to habitat quality. Consequently, evaluations of these effects are vital for devising ecological strategies and initiating regional remediation efforts. However, environmental variations in arid areas can cause habitat quality fluctuations, which complicates precise assessments. This study introduces a refined methodology that integrates remote sensing data and field survey biomass data to modify the habitat quality estimates obtained from the InVEST model in the Altai region over three decades. A comparative analysis of the unmodified, normalized difference vegetation index (NDVI)-modified and biomass-modified habitat quality estimates was conducted. The results revealed an improvement in the correlation between habitat quality and field observations, with a significant increase in the R2 value from 0.129 to 0.603. The unmodified model exhibits subtle variations in habitat quality in mountainous areas, with a slight decline in the plains. However, the modified model shows an increasing trend in mountainous areas. This finding contrasts with the reductions in mountains typically reported by other studies. The refined approach accurately expresses the variations in habitat quality across different habitat types, with declines in forested areas and improvements in shrubland and grassland regions. This model is suitable for arid regions and accommodates urban and agricultural ecosystems affected by human activities, offering empirical data for biodiversity and habitat management.

Spatial distribution and topographic gradient effects of habitat quality in the Chang-Zhu-Tan Urban Agglomeration, China

This study aimed to analyze spatio-temporal changes in habitat quality in Chang-Zhu-Tan Urban Agglomeration during the 2000–2020 period and explore its topographic gradient effects. Using land use data from this period, the InVEST model was employed to assess the spatio-temporal variations in habitat quality. The bivariate spatial autocorrelation model was used to analyze the spatial correlation characteristics between habitat quality and various topographical factors. Additionally, terrain factor analysis was utilized to study the terrain gradient effects on habitat quality in the study area. The results reveal that: (1) The primary land use changes in the study area from 2000 to 2020 predominantly involve substantial arable land and forest conversions into urban development. (2) The average habitat quality indices for 2000, 2010, and 2020 in the Chang-Zhu-Tan Urban Agglomeration stand at 0.651, 0.622, and 0.606, respectively, indicating a consistent declining trend in habitat quality. The distribution of habitat quality grades demonstrates a spatial pattern of “lower in the central surroundings, higher in the surroundings.” (3) The Chang-Zhu-Tan Urban Agglomeration shows significant positive correlations between habitat quality and topographical gradients. Spatial aggregation tendencies between habitat quality and topographical gradients primarily exhibit “high-high” and “low-low” clustering. (4) The habitat quality of the Chang-Zhu-Tan urban agglomeration exhibits a significant topographic gradient effect, primarily characterized by an increase in habitat quality with the rise of the topographic gradient. The study outcomes contribute to unveiling the spatiotemporal variations in habitat quality within the Chang-Zhu-Tan Urban Agglomeration. Moreover, leveraging different habitat types’ distinctive terrain distribution characteristics, it proposes targeted habitat conservation measures, thereby offering theoretical support for biodiversity conservation and territorial spatial planning in the study area.

Collective intelligence facilitates emergent resource partitioning through frequency-dependent learning.

Deciding where to forage must not only account for variations in habitat quality but also where others might forage. Recent studies have suggested that when individuals remember recent foraging outcomes, negative frequency-dependent learning can allow them to avoid resources exploited by others (indirect competition). This process can drive the emergence of consistent differences in resource use (resource partitioning) at the population level. However, indirect cues of competition can be difficult for individuals to sense. Here, we propose that information pooling through collective decision-making-i.e. collective intelligence-can allow populations of group-living animals to more effectively partition resources relative to populations of solitary animals. We test this hypothesis by simulating (i) individuals preferring to forage where they were recently successful and (ii) cohesive groups that choose one resource using a majority rule. While solitary animals can partially avoid indirect competition through negative frequency-dependent learning, resource partitioning is more likely to emerge in populations of group-living animals. Populations of larger groups also better partition resources than populations of smaller groups, especially in environments with more choices. Our results give insight into the value of long- versus short-term memory, home range sizes and the evolution of specialization, optimal group sizes and territoriality. This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.

Spatial and Temporal Dynamics and Multi-Scenario Forecasting of Habitat Quality in Gansu–Qinghai Contiguous Region of the Upper Yellow River

Human activities exert a profound influence on land use and land cover, and these changes directly influence habitat quality and ecosystem functioning. In the Gansu–Qinghai contiguous region of the upper Yellow River, habitat quality has undergone substantial transformations in recent years due to the synergistic impacts of natural processes and human intervention. Therefore, evaluating the effects of land use changes on habitat quality is crucial for advancing regional sustainable development and improving the worth of ecosystem services. In response to these challenges, we devised a two-pronged approach: a land use simulation (FLUS) model and an integrated valuation of ecosystem services and trade-offs (InVEST) model, leveraging remote sensing data. This integrated methodology establishes a research framework for the evaluation and simulation of spatial and temporal variations in habitat quality. The results of the study show that, firstly, from 1980 to 2020, the habitat quality index in the Gansu–Qinghai contiguous region of the upper Yellow River decreased from 0.8528 to 0.8434. Secondly, our predictions anticipate a decrease in habitat quality, although the decline is not pronounced across all scenarios. The highest habitat quality values were projected under the EP (Ecology Priority) scenario, followed by the CLP (Cultivated Land Priority) scenario, while the BAU (Business as Usual) scenario consistently yielded the lowest values in all three scenarios. Finally, the ecological land, including forest land and grassland, consistently occupied areas characterized by high habitat quality. In contrast, Construction land consistently appeared in regions associated with low habitat quality. The implementation of conservation measures emerges as a crucial strategy, effectively limiting the expansion of construction land and promoting the augmentation of forest land and grassland cover. This approach serves to enhance overall habitat quality. These outcomes furnish a scientific foundation for the judicious formulation of future land-use policies and ecological protection measures.

Recruitment of European sea bass (Dicentrarchus labrax) in northerly UK estuaries indicates a mismatch between spawning and fisheries closure periods.

European sea bass (Dicentrarchus labrax) is a species of high commercial and recreational value, but it exhibits highly variable recruitment rates and has been subject to recent declines. Emergency management measures put in place to protect spawning stocks include the annual closure of commercial and recreational fisheries over a 2-month, February-March, window. Whether this protection measure is having the desired outcome for this data-poor species remains unclear. Otolith microstructural analyses (counts and widths of daily growth rings and check marks indicative of settlement) were used to estimate (1) spawn timing, (2) pelagic larval duration and settlement timing, (3) growth rate and condition, and (4) the otolith-fish size relationship for juvenile European sea bass caught from two estuaries in Wales (Dwyryd, Y Foryd), located at the northern edge of the species range. We observed a significant mismatch between the timing of fisheries closures and the spawning, with 99.2% of recruits having been spawned after the fishery had reopened (back-calculated median spawn date = May 5 ± 17 days SD), suggesting that the closure may be too early to adequately protect this population. Further, we present the first empirically derived estimates of pelagic larval duration for sea bass recruits settling in UK habitats, which showed a strong negative relationship with spawn date. Finally, we found significant differences in fish condition between the two estuaries, suggesting local variation in habitat quality. The results suggest that the timing of current fisheries closures may not be adequately protecting the spawners supplying these northernmost estuaries, which are likely to become increasingly important as sea bass distributions shift northward in our climate future.

Characterization and Multi-Scenario Prediction of Habitat Quality Evolution in the Bosten Lake Watershed Based on the InVEST and PLUS Models

Habitat quality is an important basis for human well-being and the achievement of sustainable development. Based on land-use data for the Bosten Lake Basin in 2000, 2005, 2010, 2015, and 2022, the PLUS and InVEST models are applied in this study to predict and analyze land-use changes and explore the spatial and temporal evolution characteristics of the region’s habitat quality. Additionally, we use a geographic detector model to reveal the drivers of spatial variation in habitat quality. The results show that: (1) Land use in Bosten Lake Basin is dominated by grassland and bare land, with an area share of 93.21%. Habitat quality shows a trend of degradation followed by improvement, with a spatial pattern of high in the northwest and low in the southeast. (2) Habitat quality in 2030 increased from 2022 in all cases, with a mean of 0.354 for the natural development scenario, a maximum of 0.355 for the ecological development scenario, and a minimum of 0.353 for the economic development scenario. (3) The main drivers affecting habitat quality in the Bosten Lake watershed are DEM, mean annual precipitation (MAP), and GDP per capita. X1∩X4 (0.50) and X4∩X10 (0.51) are the interaction factors with the largest dominant effect in 2000, 2010 and 2020, respectively.

Evolutionary patterns and influencing factors of relationships among ecosystem services in the hilly red soil region of Southern China.

As a crucial ecological protection area in China, the Southern hilly red soil region is characterized by uneven spatial and temporal distribution of ecological landscape elements, unpredictable and changeable interrelationships between them, diversified driving factors, and lack of comprehensive consideration of ecosystem services. In order to better understand the interaction between ecosystem services, restore regional ecology, and promote sustainable development, the evolution law and influencing mechanism of ecosystem services and their driving factors are quantitatively analyzed in the study. Based on simulations of different ecosystem services from 2000 to 2020, their spatial and temporal changes and the contributions of main drivers are quantified, their trade-offs and synergies are analyzed, and the changing rules under the influence of natural factors and socioeconomic factors are explored. The results show that (1) the crop production significantly increases in the southwest and north regions, the habitat quality decreases in urban and coastal areas, and the soil retention and water yield show an increasing trend from west to east. (2) Land use/cover is the main driver of carbon storage and habitat quality variation, and precipitation is an important driver of water yield spatial variation. (3) The crop production and the other four ecosystem services show a trade-offs relationship, and the relationship between supporting services and regulating services is the synergetic. (4) The altitude weakens the synergistic relationship between soil retention and habitat quality/carbon storage, while it enhances the synergistic relationship between soil retention and water yield. Driven by precipitation factors, ecosystem services related to water yield have significant differences in the change. The population density enhances the trade-offs of crop production and soil retention, as well as the synergistic relationship between soil retention and habitat quality/carbon storage. In different land use/cover (LULC), the influence of urban land on ecosystem services relationship change is more obvious. Overall, this study can provide scientific bases and policy suggestions for ecosystem protection/restoration in the red soil region of Southern China, which has an important theoretical and practical significance.

How do different processes of habitat fragmentation affect habitat quality? – Evidence from China

Large-scale loss and fragmentation of natural habitats is one of the critical factors in the global decline of biodiversity. Habitat quality is the foundation for supporting biodiversity, so exploring the mechanisms by which habitat fragmentation affects habitat quality is important for biodiversity protection. However, little is known about the specific forms that various processes of habitat fragmentation affect habitat quality. Taking China as an example, the three processes of habitat fragmentation (the decrease in habitat area, the increase in habitat isolation, and the increase in habitat edge) and variations in habitat quality were quantitatively assessed from 2000 to 2020. On this basis, Pearson coefficients, Generalized Additive Model (GAM) and Geographical detector were employed to examine the linear\ on-linear\\combined impacts of habitat fragmentation different processes on habitat quality. The results indicated that there was a clear trend of habitat fragmentation and degradation of habitat quality in 2000–2020. 56.94%, 42.33%, and 50.89% of the area experienced the decrease in habitat area, the increase in habitat isolation, and the increase in habitat edge, respectively, and 63.12% experienced degradation of habitat quality. All three of these habitat fragmentation processes result in a downward trend in habitat quality. However, the specific form of impacts of habitat fragmentation different processes on habitat quality showed non-linear characteristics. The decrease in habitat area and the increase in habitat isolation consistently had a significant negative influence on habitat quality, albeit with varying strengths at different segments. While the increase in habitat edge causes an overall decrease in habitat quality, the two have a more complex non-linear relationship, with response curves varied between positive and negative correlations. In addition, negative impacts on habitat quality are exacerbated when multiple habitat fragmentation processes occur simultaneously. These findings reveal the complex impacts of different habitat fragmentation processes on habitat quality and inform the development of more rational landscape planning and biodiversity conservation measures in China.

Research on habitat quality in arid urban agglomerations: Influencing mechanisms and multi‐scenario simulations

AbstractIn the context of climate change and rapid urbanization, there have been unparalleled changes in land use and land cover (LULC), resulting in substantial impacts on the surrounding habitat quality (HQ), particularly in ecologically vulnerable arid regions. However, previous studies on the influencing mechanisms of HQ in arid urban agglomerations and future multi‐scenario simulations remain limited. To fill this knowledge gap, this study aimed to reveal the influencing mechanisms in HQ changes and to develop a multi‐scenario HQ assessment framework within arid urban agglomerations. We assessed the spatiotemporal variations in HQ using the InVEST model and three periods of LULC data for the urban agglomeration on the northern slope of the Tianshan Mountains (UANSTM), and the partial least squares structural equation model was introduced to explore the interactions between natural and non‐natural factors and their impacts on HQ. Additionally, we coupled multi‐objective programming and PLUS models to predict the LULC under different optimization scenarios (natural development scenario (NDS), ecological protection scenario (EPS), ecological–economic coordinated scenario, and economic development scenario) for the UANSTM in 2030, and to assess HQ. Results show that (1) the HQ index of the UANSTM was 0.507, 0.520, and 0.495 in 2000, 2010, and 2020 respectively, with a spatial distribution pattern of high values in the west, low values in the east, and high in the central and low in the north and south; (2) geomorphic, climatic, and LULC factors have direct positive effects on HQ, while socio‐economic factors have a direct negative effect on HQ. In addition, geomorphic, socio‐economic, and climatic factors also influence HQ through potential indirect paths. Climatic and LULC factors enhance the positive effect of geomorphic on HQ while counteracting the direct negative effect of socio‐economic factors on HQ. Climatic factors have the largest negative effect on HQ through their influence on LULC; (3) according to the four scenarios in 2030, the highest HQ index (increased by 0.13%) was found under the EPS, which also aligns more closely with SDGs. Conversely, NDS showed the lowest HQ index (declined by 2.59%). The research results could provide a scientific basis for promoting sustainable land management and ecological conservation for the UANSTM.

Population status, habitat preferences and predictive current and future distributions of three endangered Silene species under changing climate.

One of the most crucial steps in the practical conservation of endangered endemic mountain plants is to address their population size status and habitat requirements concurrently with understanding their response to future global warming. Three endangered Silene species-Silene leucophylla Boiss., S. schimperiana Boiss., and S. oreosinaica Chowdhuri-in Egypt were the focus of the current study. These species were examined for population status change, habitat quality variables (topography, soil features, and threats), and predictive current and future distributions. To find population size changes, recent field surveys and historical records were compared. Using Random Forest (RF) and Canonical Correspondence Analysis (CCA), habitat preferences were assessed. To forecast present-day distribution and climate change response, an ensemble model was used. The results reported a continuous decline in the population size of the three species. Both RF and CCA addressed that elevation, soil texture (silt, sand, and clay fractions), soil moisture, habitat-type, chlorides, electric conductivity, and slope were among the important variables associated with habitat quality. The central northern sector of the Saint Catherine area is the hotspot location for the predictive current distribution of three species with suitable areas of 291.40, 293.10, and 58.29 km2 for S. leucophylla, S. schimperiana, and S. oreosinaica, respectively. Precipitation-related variables and elevation were the key predictors for the current distribution of three Silene species. In response to climate change scenarios, the three Silene species exhibited a gradual contraction in the predictive suitable areas with upward shifts by 2050 and 2070. The protection of these species and reintroduction to the predicted current and future climatically suitable areas are urgent priorities. Ex-situ conservation and raised surveillance, as well as fenced enclosures may catapult as promising and effective approaches to conserving such threatened species.

Population level behavioural responses to variation in habitat quality across multiple locations in a fragmented landscape

Population level behavioural responses to variation in habitat quality across multiple locations in a fragmented landscape

Spatiotemporal variation of habitat quality and its response to fractional vegetation cover change and human disturbance in the Loess Plateau

It is of great practical significance to regional ecological conservation and restoration to explore the spatiotemporal variation characteristics of habitat quality in the ecologically fragile Loess Plateau. This study firstly explored the habitat quality in the Loess Plateau during 2000-2020 with the Integrated Valuation of Ecosystem Services and Trade-offs model. Then this study revealed the response characteristics of habitat quality to the fractional vegetation cover (FVC) change and human disturbance with the geographically weighted regression (GWR) model. Results showed habitat quality tended to improve in 51.16% of the study area, and area of high or very high habitat quality increased by 1.78%. Besides, FVC showed dominantly significant increase (62.42%) and high stability (69.66%) in the study area, and human disturbance increased remarkably in 18.11% of the study area but maintained the same level in 91.83% of the study area. Additionally, areas with positive correlation between habitat quality change and FVC and between habitat quality change and human disturbance change accounted for 52.56% and 37.38% of the study area, respectively, indicating FVC played dominant role in affecting the regional habitat quality variation. This study can provide important decision support information for the future ecological conservation of the Loess Plateau.

Study of spatiotemporal variation and driving factors of habitat quality in the northern foothills of the Qinling Mountains: a case study of Xi’an, China

As earth surface human activities become more frequent, global ecosystem service functions and especially biodiversity maintenance functions are challenged. This study aimed to analyze spatiotemporal changes in Xi‘an section of the northern foothills of the Qinling Mountains from 1990 to 2020. Temporal and spatial changes in habitat quality in the study area were visualized using InVEST model and land use data, and factors affecting habitat quality were analyzed using Geodetector. The results showed that during the study period, the cultivated land, grassland, and water decreased by 16.40%, 74.37%, and 35.39%, respectively, while the area of forest land and construction land increased, among which the construction land increased by 117.70%, the largest increase, and the forest land increased by 8.47%. The main changes in land use are the conversion of cultivated land into forest land and construction land, and the conversion of grassland into forest land and cultivated land. During the period 1990–2020, the average habitat quality index in the study area changed from 0.8617 to 0.8585, showing a slow decreasing trend. The spatial distribution of habitat quality showed a trend of “high in the south, moderate in the north, and low in the northwest”. The high habitat quality was mainly concentrated in the southern forest land, the middle habitat quality was mainly distributed in the northern cultivated land, and the low habitat quality was mainly distributed in the northwest construction land. The land use type has a great influence on habitat quality, and the interaction between any two factors is stronger than that of a single factor. The temporal and spatial variation of habitat quality is influenced by both natural and human factors. This study provides a theoretical basis for ecological protection and nature reserve planning in the Qinling Mountains region.

Interplay between pond size and matrix extent drives odonate diversity patterns in a fragmented landscape

AbstractLandscape fragmentation impacts freshwater habitats and their quality, affecting aquatic insect assemblages. Adjacent terrestrial areas are important secondary habitats where amphibiotic insects mature, feed, find mates, and move to locate aquatic breeding habitats. Using a factorial design with 27 small and large ponds within small and large natural patches in an exotic tree plantation-fragmented landscape of South Africa, and odonates as model organisms, we investigated (1) how pond size/natural terrestrial patch size interaction affects odonate diversity patterns versus habitat quality variables, and (2) determined whether anisopterans and zygopterans respond differently to landscape fragmentation. Species richness was similar among ponds. However, odonate abundance was highest in large ponds regardless of natural terrestrial patch size. Zygopteran functional richness and diversity was driven by pond and natural patch size, suggesting that zygopterans are sensitive to landscape fragmentation. In contrast, anisopterans were more resilient to fragmentation and more likely to select suitable habitats following water chemistry and vegetation characteristics. Overall, large ponds were occupied by different odonate assemblages compared to small ponds, and occupancy was strongly associated with mobility traits. These findings emphasize that ponds in both small and large natural terrestrial patches have conservation value. A pondscape that represents various pond sizes is important for maintaining regional odonate diversity. Pond conservation needs to be considered in the wider terrestrial context, which host a range of important secondary habitats. Adjacent natural terrestrial habitats also connect nearby aquatic habitats, which enable insects to move across the landscape in response to natural and artificial drivers.

Using individual-based bioenergetic models to predict the aggregate effects of disturbance on populations: A case study with beaked whales and Navy sonar.

Anthropogenic activities can lead to changes in animal behavior. Predicting population consequences of these behavioral changes requires integrating short-term individual responses into models that forecast population dynamics across multiple generations. This is especially challenging for long-lived animals, because of the different time scales involved. Beaked whales are a group of deep-diving odontocete whales that respond behaviorally when exposed to military mid-frequency active sonar (MFAS), but the effect of these nonlethal responses on beaked whale populations is unknown. Population consequences of aggregate exposure to MFAS was assessed for two beaked whale populations that are regularly present on U.S. Navy training ranges where MFAS is frequently used. Our approach integrates a wide range of data sources, including telemetry data, information on spatial variation in habitat quality, passive acoustic data on the temporal pattern of sonar use and its relationship to beaked whale foraging activity, into an individual-based model with a dynamic bioenergetic module that governs individual life history. The predicted effect of disturbance from MFAS on population abundance ranged between population extinction to a slight increase in population abundance. These effects were driven by the interaction between the temporal pattern of MFAS use, baseline movement patterns, the spatial distribution of prey, the nature of beaked whale behavioral response to MFAS and the top-down impact of whale foraging on prey abundance. Based on these findings, we provide recommendations for monitoring of marine mammal populations and highlight key uncertainties to help guide future directions for assessing population impacts of nonlethal disturbance for these and other long-lived animals.

Do beluga whales truly migrate? Testing a key trait of the classical migration syndrome

BackgroundMigration enables organisms to access resources in separate regions that have predictable but asynchronous spatiotemporal variability in habitat quality. The classical migration syndrome is defined by key traits including directionally persistent long-distance movements during which maintenance activities are suppressed. But recently, seasonal round-trip movements have frequently been considered to constitute migration irrespective of the traits required to meet this movement type, conflating common outcomes with common traits required for a mechanistic understanding of long-distance movements. We aimed to test whether a cetacean ceases foraging during so-called migratory movements, conforming to a trait that defines classical migration.MethodsWe used location and dive data collected by satellite tags deployed on beluga whales (Delphinapterus leucas) from the Eastern Beaufort Sea population, which undertake long-distance directed movements between summer and winter areas. To identify phases of directionally persistent travel, behavioural states (area-restricted search, ARS; or Transit) were decoded using a hidden-Markov model, based on step length and turning angle. Established dive profiles were then used as a proxy for foraging, to test the hypothesis that belugas cease foraging during these long-distance transiting movements, i.e., they suppress maintenance activities.ResultsBelugas principally made directed horizontal movements when moving between summer and winter residency areas, remaining in a Transit state for an average of 75.4% (range = 58.5–87.2%) of the time. All individuals, however, exhibited persistent foraging during Transit movements (75.8% of hours decoded as the Transit state had ≥ 1 foraging dive). These data indicate that belugas actively search for and/or respond to resources during these long-distance movements that are typically called a migration.ConclusionsThe long-distance movements of belugas do not conform to the traits defining the classical migration syndrome, but instead have characteristics of both migratory and nomadic behaviour, which may prove adaptive in the face of unpredictable environmental change. Such patterns are likely present in other cetaceans that have been labeled as migratory. Examination of not only horizontal movement state, but also the vertical behaviour of aquatic animals during directed movements is essential for identifying whether a species exhibits traits of the classical migration syndrome or another long-distance movement strategy, enabling improved ecological inference.

Evaluating future habitat quality responding to land use change under different city compaction scenarios in Southern China

Rapid urban expansion, accompanied by intense landscape changes, significantly affects natural habitats. Promoting sustainable urban development, such as the compact city strategy, is essential to balance ecosystem conservation and socio-economic development. Previous studies have generally focused on exploring the ecosystem impact of urban expansion concerning the future projections of climate, population, and economic development. Less attention has been paid to how different urban forms modify the landscape and affect habitats at a fine resolution. This study has built a framework to demonstrate future land use change under various city compaction scenarios using a bottom-up Cellular Automata (CA) model and a top-down Markov model. Then the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model was incorporated to evaluate the resultant habitat quality. By taking the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as the study area, three future compact city scenarios in 2040 and 2060 were proposed to examine the accumulative effect of urban growth. The results show that by 2040, the high-compact scenario will cause the highest habitat quality degradation among all scenarios due to marked cropland displacement induced by urban edge expansion. By 2060, intensified medium or low-compact scenarios tend to create new urban clusters outside the existing urban areas, resulting in severe habitat isolation and fragmentation. The GBA presents significant spatial heterogeneity in habitat quality variation because of the uneven development between the core and key node cities. Our results suggest that a collaborative strategy should be promoted to motivate the unique advantages of each city. This could include maintaining the amount and connectivity of open space under city integration processes and reserving high-quality cropland, such as fish-pod-based agriculture, to mitigate habitat quality degradation. This study can provide insights for developing long-term land use management when applying compact city strategies to balance ecological conservation and urban development needs.