Spatial Scales Research Articles

Multi-scale beta-diversity patterns in testate amoeba communities: species turnover and nestedness along a latitudinal gradient.

The relationship between species diversity and spatial scale is a central topic in spatial community ecology. Latitudinal gradient is among the core mechanisms driving biodiversity distribution on most scales. Patterns of β-diversity along latitudinal gradient have been well studied for aboveground terrestrial and marine communities, whereas soil organisms remain poorly investigated in this regard. The West Siberian Plain is a good model to address diversity scale-dependence since the latitudinal gradient does not overlap with other possible factors such as elevational or maritime. Here, we collected 111 samples following hierarchical sampling (sub-zones, ecosystem types, microhabitat and replicate samples) and performed multi-scale partitioning of β-diversity of testate amoeba assemblages as a model of study. We found that among-ecosystem β-diversity is a leading scale in testate amoeba assemblages variation. Rare species determine β-diversity at all scale levels especially in the northern regions, where rare taxa almost exclusively accounted for the diversity at the ecosystem level. β-Diversity is generally dominated by the turnover component at all scales in lower latitudes, whereas nestedness prevailed at among-ecosystem scale in higher latitudes. These findings indicate that microbial assemblages in northern latitudes are spatially homogeneous and constrained by historical drivers at larger scales, whereas in southern regions, it is dominated by the turnover component both at the microhabitat and ecosystem scales and therefore determined by recent vegetation and environmental heterogeneity. Overall, we have provided the evidence for the existence of negative latitudinal gradient for among-ecosystem β-diversity but not for among-microhabitat and among-sample β-diversity for terrestrial testate amoeba communities.

A stochastic and analytical model of hierarchical fragmentation. The fragmentation of gas structures into young stellar objects in the interstellar medium

Molecular clouds are the most important incubators of young stars clustered in various stellar structures whose spatial extension can vary from a few AU to several thousand AU. Although the reality of these stellar systems has been established, the physical origin of their multiplicity remains an open question. Our aim was to characterise these stellar groups at the onset of their formation by quantifying both the number of stars they contain and their mass using a hierarchical fragmentation model of the natal molecular cloud. We developed a stochastic and predictive model that reconciles the continuous multi-scale structure of a fragmenting molecular cloud with the discrete nature of the stars that are the products of this fragmentation. In this model a gas structure is defined as a multi-scale object associated with a subregion of a cloud. Such a structure undergoes quasi-static subfragmentation until star formation. This model was implemented within a gravo-turbulent fragmentation framework to analytically follow the fragmentation properties along spatial scales using an isothermal and adiabatic equations of state (EOSs). We highlighted three fragmentation modes depending on the amount of fragments produced by a collapsing gas structure, namely a hierarchical mode, a monolithic mode, and a mass dispersal mode. Using an adiabatic EOS we determined a characteristic spatial scale where further fragmentation is prevented, around a few tens of AU. We show that fragmentation is a self-regulated process as fragments tend to become marginally unstable following a $M R$ Bonnor--Ebert-like mass--size profile. Supersonic turbulent fragmentation structures the cloud down to $R 0.1$ pc, and gradually turns into a less productive Jeans-type fragmentation under subsonic conditions so hierarchical fragmentation is a scale dependant process Our work suggests that pre-stellar objects resulting from gas fragmentation, have to progressively increase their accretion rate in order to form stars. A hierarchical fragmentation scenario is compatible with both the multiplicity of stellar systems identified in Taurus and the multi-scale structure extracted within NGC 2264 molecular cloud. This work suggests that hierarchical fragmentation is one of the main mechanisms explaining the presence of primordial structures of stellar clusters in molecular clouds.

The importance of spatial scale and vegetation complexity in woody species diversity and its relationship with remotely sensed variables

Plant species diversity is key to ecosystem functioning, but in recent decades anthropogenic activities have prompted an alarming decline in this community trait. Thus, developing strategies to understand diversity dynamics based on affordable and efficient remote sensing monitoring is essential, as well as examining the relevance of spatial scale and vegetation structural complexity to these dynamics. Here, we used two mathematical approaches to assess the relationship between tropical woody species diversity and spectral diversity in a human-modified landscape in two vegetation types differing in their degree of complexity. Vegetation complexity was measured through the fraction of species that concentrate different proportions of the cumulative importance value index. Species diversity was assessed using Hill numbers at three spatial scales, and metrics of spectral heterogeneity, vegetation indices, as well as raw data from Landsat 9 and Sentinel-2 sensors were calculated and analysed through general linear models (GLM) and Random Forest. Vegetation complexity emerged as an important variable in modelling species from remote sensing metrics, indicating the need to model species diversity by vegetation type rather than region. Hill numbers showed different relationships with remotely sensed metrics, in consistency with the scale-dependency of ecological processes on species diversity. Contrary to multiple previous reports, in our study, GLMs produced the best fits between Hill numbers of all orders and remotely sensed metrics. If we are to meet the need of conducting efficient and speedy woody species diversity monitoring globally, we propose modelling this diversity from remotely-sensed variables as an attractive strategy, so long as the intrinsic properties of each vegetation type are acknowledged to avoid under- or overestimation biases.

Electron transport through two interacting channels in Azurin-based solid-state junctions

The fundamental question of "what is the transport path of electrons through proteins?" initially introduced while studying long-range electron transfer between localized redox centers in proteins in vivo is also highly relevant to the transport properties of solid-state, dry metal-protein-metal junctions. Here, we report conductance measurements of such junctions, Au-(Azurin monolayer ensemble)-Bismuth (Bi) ones, with well-defined nanopore geometry and ~103 proteins/pore. Our results can be understood as follows. (1) Transport is via two interacting conducting channels, characterized by different spatial and time scales. The slow and spatially localized channel is associated with the Cu center of Azurin and the fast delocalized one with the protein's polypeptide matrix. Transport via the slow channel is by a sequential (noncoherent) process and in the second one by direct, off-resonant tunneling. (2) The two channels are capacitively coupled. Thus, with a change in charge occupation of the weakly coupled (metal center) channel, the broad energy level manifold, responsible for off-resonance tunneling, shifts, relative to the electrodes' Fermi levels. In this process, the off-resonance (fast) channel dominates transport, and the slow (redox) channel, while contributing only negligibly directly, significantly affects transport by intramolecular gating.

Imaging the large-scale and cellular response to focal traumatic brain injury in mouse neocortex.

Traumatic brain injury (TBI) affects neural function at the local injury site and also at distant, connected brain areas. However, the real-time neural dynamics in response to injury and subsequent effects on sensory processing and behavior are not fully resolved, especially across a range of spatial scales. We used in vivo calcium imaging in awake, head-restrained male and female mice to measure large-scale and cellular resolution neuronal activation, respectively, in response to a mild TBI induced by focal controlled cortical impact (CCI) injury of the motor cortex (M1). Widefield imaging revealed an immediate CCI-induced activation at the injury site, followed by a massive slow wave of calcium signal activation that traveled across the majority of the dorsal cortex within approximately 30 s. Correspondingly, two-photon calcium imaging in primary somatosensory cortex (S1) found strong activation of neuropil and neuronal populations during the CCI-induced traveling wave. A depression of calcium signals followed the wave, during which we observed atypical activity of a sparse population of S1 neurons. Longitudinal imaging in the hours and days after CCI revealed increases in the area of whisker-evoked sensory maps at early time points, in parallel to decreases in cortical functional connectivity and behavioral measures. Neural and behavioral changes mostly recovered over hours to days in our mild-TBI model, with a more lasting decrease in the number of active S1 neurons. Our results provide novel spatial and temporal views of neural adaptations that occur at cortical sites remote to a focal brain injury.

Bike-Sharing Travel Demand Forecasting via Travel Environment-Based Modeling

This research aims to address the limited consideration given to non-motorized transport facilities in current studies on shared bike travel demand forecasting. This study is the first to propose a method that applies complete citywide non-motorized facility data to predict bike-sharing demand. This study employs a multiscale geographically weighted regression (MGWR) model to examine the effects of non-motorized transport facility conditions, quantity of intersections, and land use per unit area on riding demand at various spatial scales. The results of comparison experiments reveal that riding demand is substantially affected by non-motorized transport facilities and the quantity of intersections.

A joint spatio-temporal characterization of the major meteorological droughts in Europe

Abstract Drought can be considered one of the most severe and complex weather-related natural hazards. It is a relevant stressor for ecosystems, affecting vegetation, ecosystem productivity, and water and carbon cycles, with a complex web of related impacts. Despite the interlink between the spatial and temporal scales of droughts, these two aspects are often studied separately. In addition, studies generally focus on detecting the events, without trying to investigate similarities among them. In this work, we introduce a set of tools used to summarize the main properties of major droughts in Europe, with the goal of subdividing the events in groups characterized by similar properties. We used a European dataset of meteorological droughts (from 1981 to 2020) that detects events based on the Standardized Precipitation Index using an event-oriented spatio-temporal clustering algorithm. From the analysis, we identified three groups of major meteorological droughts: a first group that is comprised by warm-season events, characterized by a longer duration, a shorter early growing phase, and a longer exhaustion phase; a second group, less numerous, comprised by droughts occurring during the cold season, that tend to have a shorter duration, a longer early growing phase and a shorter exhaustion phase; and a third group comprised of droughts occurring across the two periods. This last class is characterized by a longer duration and a high variability in most of the other characteristics, suggesting that these events may be associated with a large range of driving mechanisms. The proposed procedure allows for a drought classification that can be used for better understanding the mechanisms behind spatio-temporal evolution of these events.

Resilience in River Corridors: How Much Do We Need?

AbstractResilience in river corridors refers to the ability to absorb disturbance and maintain processes, forms, and functions that support the river ecosystem and provide ecosystem services. Resilience derives from characteristics such as three‐dimensional connectivity, spatial heterogeneity, and physical and ecological integrity. Resilience is important as climate warming and growing human populations and consumptive demands change the disturbance regime affecting river corridors. Consequently, river management increasingly focuses on enhancing natural characteristics that create river resilience via (a) identifying the processes and features that promote and sustain resilience, (b) identifying portions of a river network and/or river corridor that are most resilient or most influential in creating resilience at larger spatial scales, and (c) protecting and restoring features that create resilience. Although the basic conceptual framework for these activities is well established, critical questions remain with respect to how reach‐scale management creates catchment‐scale results.

Rhizosphere microbial community construction during the latitudinal spread of the invader Chromolaena odorata

The colonization of alien plants in new habitats is typically facilitated by microorganisms present in the soil environment. However, the diversity and structure of the archaeal, bacterial, and fungal communities in the latitudinal spread of alien plants remain unclear. In this study, the rhizosphere and bulk soil of Chromolaena odorata were collected from five latitudes in Pu’ er city, Yunnan Province, followed by amplicon sequencing of the soil archaeal, bacterial, and fungal communities. Alpha and beta diversity results revealed that the richness indices and the structures of the archaeal, bacterial, and fungal communities significantly differed along the latitudinal gradient. Additionally, significant differences were observed in the bacterial Shannon index, as well as in the structures of the bacterial and fungal communities between the rhizosphere and bulk soils. Due to the small spatial scale, trends of latitudinal variation in the archaeal, bacterial, and fungal communities were not pronounced. Total potassium, total phosphorus, available nitrogen, available potassium and total nitrogen were the important driving factors affecting the soil microbial community structure. Compared with those in bulk soil, co-occurrence networks in rhizosphere microbial networks presented lower complexity but greater modularity and positive connections. Among the main functional fungi, arbuscular mycorrhizae and soil saprotrophs were more abundant in the bulk soil. The significant differences in the soil microbes between rhizosphere and bulk soils further underscore the impact of C. odorata invasion on soil environments. The significant differences in the soil microbiota along latitudinal gradients, along with specific driving factors, demonstrate distinct nutrient preferences among archaea, bacteria, and fungi and indicate complex microbial responses to soil nutrient elements following the invasion of C. odorata.

Using spatial capture‐recapture models to estimate spotted hyaena (Crocuta crocuta) population density and assess the influence of sex‐specific covariates on space use and detection probability

AbstractDespite being resident or reintroduced to multiple South African protected areas, spotted hyaena (Crocuta crocuta) have been subject to limited population monitoring and are not managed in the same intensive way as other large carnivores. Considering the species' significant influence on ecosystem processes, robust estimates of population density are necessary to inform conservation management. In this study, we ran a single‐season camera trap survey in the Main Camp section of Addo Elephant National Park (Addo), South Africa, and used spatial capture‐recapture (SCR) models to estimate spotted hyaena population density. Spotted hyaena density was estimated to be 11.13 (± SE 1.96) individuals/100 km2, with an estimated abundance of 37 (± SE 6.44) individuals. Using our database of sexed spotted hyaena individuals, we found no significant difference for sex‐specific SCR parameters (baseline encounter probability and spatial scale parameter), suggesting the incorporation of sex‐specific information may not be as necessary for spotted hyaena as it is for territorial felids and other species with more pronounced differences in range size. Spotted hyaena density in Addo was comparable to previous SCR studies and towards the higher end of known densities. Our estimate provides an important baseline for monitoring reintroduction success in Addo, and we advocate for increased SCR monitoring of spotted hyaena in South African protected areas to inform a metapopulation approach to the species' management.

Peak beta diversity occurs at regional spatial grains

Beta diversity (β) quantifies the dissimilarity between communities and is thus fundamental to biogeography and spatial ecology. However, multiple and conflicting hypotheses exist to explain how β varies with spatial scale (here grain within a constant extent). Some resolution on spatial scaling of β may help clarify long-standing debate about: (a) β itself and (b) the ecological community concept, because the clearest spatial size of an ecological community corresponds to the scale with maximal β. Here we test five alternative hypotheses for β spatial scaling by calculating β for four very different taxa (ants, birds, diatoms, and trees) at spatial grains ranging from one to one million km2 in a constant spatial extent (contiguous USA). We also test repeatability for: (a) summer and winter bird β in six consecutive years; (b) trees through time (4 years, spaced 5 years apart). Specifically, we organize point data into hexagonal polygons, and then calculate mean pairwise β between each hexagon and its neighbors. We also calculate the deviation of β from two null models (assuming either spatial heterogeneity or homogeneity). For multiple reasons, β deviation based on spatial heterogeneity was preferable to that based on spatial homogeneity. For all taxa, β peaks at regional scales: trees ~300 km2; winter birds ~500 km2; summer birds ~2000 km2; ants ~2000 km2; diatoms ~11,000 km2. Also, spatial scaling is consistent inter-annually (birds, trees) and sensitive to seasonality (birds). Results broadly support the regional community concept and, based on the variety of taxa evaluated here, similar patterns are likely across the tree of life. Local ecological and evolutionary forces scale up to form regional community patterns and results here support efforts to coordinate local conservation efforts in regions (e.g., corridors and networks) to best conserve biodiversity. Beta diversity peaked at substantial spatial scales for all taxa evaluated here (ants, birds, diatoms, trees), suggesting a general pattern. The regional community concept advanced by Robert Ricklefs is supported empirically, in preference to four other hypotheses also tested. Beta diversity calculations used a relatively new deviation from a spatially heterogeneous null, which modestly adjusted observed beta diversity. Results support use of this newer beta deviation rather than the older beta deviation based on spatial homogeneity. Given that ecological communities appear regional in scale, local biodiversity conservation work can best ensure success if it is regionally coordinated.

Partial asynchrony of coniferous forest carbon sources and sinks at the intra-annual time scale

As major terrestrial carbon sinks, forests play an important role in mitigating climate change. The relationship between the seasonal uptake of carbon and its allocation to woody biomass remains poorly understood, leaving a significant gap in our capacity to predict carbon sequestration by forests. Here, we compare the intra-annual dynamics of carbon fluxes and wood formation across the Northern hemisphere, from carbon assimilation and the formation of non-structural carbon compounds to their incorporation in woody tissues. We show temporally coupled seasonal peaks of carbon assimilation (GPP) and wood cell differentiation, while the two processes are substantially decoupled during off-peak periods. Peaks of cambial activity occur substantially earlier compared to GPP, suggesting the buffer role of non-structural carbohydrates between the processes of carbon assimilation and allocation to wood. Our findings suggest that high-resolution seasonal data of ecosystem carbon fluxes, wood formation and the associated physiological processes may reduce uncertainties in carbon source-sink relationships at different spatial scales, from stand to ecosystem levels.

Spatiotemporally non-stationary evolution of groundwater levels in Poyang Lake Basin driven by meteorological and hydrological factors

The complex relationship between wet-dry transition in the Poyang Lake basin and groundwater storage significantly affects the lake's hydrology, downstream ecological state, and overall security along the Yangtze River in China. There is, however, a notable lack of systematic exploration into how various factors drive spatiotemporal variability in groundwater level (GWL). Using local indicators of spatial association (LISA), spatial non-stationarity models, and multi-source data, our analysis explores the spatial distribution of GWL and quantifies the influence of driving factors on its spatiotemporal non-stationarity at annual and monthly scales. We also compare driving factor contributions in hilly, plain, and local areas within the Poyang Lake basin. Our findings reveal significant local clustering of GWL, indicating substantial spatial autocorrelation and geographic heterogeneity in GWL. Influencing factors exhibit non-stationary effects on GWL at spatial and temporal scales, with precipitation (P), ground surface elevation (GSE), and soil moisture (SM) being primary contributors, generally exerting positive effects. SM contributes most during dry years and normal periods. P and the Palmer Drought Severity Index (PDSI) have greater impacts in hilly areas, while GSE shows the opposite trend. Rainfall is a source of groundwater recharge, with a lagged response observed in GWL to rainfall in this basin. The lag time is about 1–2 months. Evapotranspiration is not the dominant discharge pathway. The decrease in GWL during the dry season is mainly due to reduced precipitation recharge and increased lateral groundwater discharge from areas of high hydraulic head to areas of low hydraulic head.

Seasonal drought treatments impact plant and microbial uptake of nitrogen in a mixed shrub grassland on the Colorado Plateau.

For many drylands, both long- and short-term drought conditions can accentuate landscape heterogeneity at both temporal (e.g., role of seasonal patterns) and spatial (e.g., patchy plant cover) scales. Furthermore, short-term drought conditions occurring over one season can exacerbate long-term, multidecadal droughts or aridification, by limiting soil water recharge, decreasing plant growth, and altering biogeochemical cycles. Here, we examine how experimentally altered seasonal precipitation regimes in a mixed shrub grassland on the Colorado Plateau impact soil moisture, vegetation, and carbon and nitrogen cycling. The experiment was conducted from 2015 to 2019, during a regional multidecadal drought event, and consisted of three precipitation treatments, which were implemented with removable drought shelters intercepting ~66% of incoming precipitation including: control (ambient precipitation conditions, no shelter), warm season drought (sheltered April-October), and cool season drought (sheltered November-March). To track changes in vegetation, we measured biomass of the dominant shrub, Ephedra viridis, and estimated perennial plant and ground cover in the spring and the fall. Soil moisture dynamics suggested that warm season experimental drought had longer and more consistent drought legacy effects (occurring two out of the four drought cycles) than either cool season drought or ambient conditions, even during the driest years. We also found that E. viridis biomass remained consistent across treatments, while bunchgrass cover declined by 25% by 2019 across all treatments, with the earliest declines noticeable in the warm season drought plots. Extractable dissolved inorganic nitrogen and microbial biomass nitrogen concentrations appeared sensitive to seasonal drought conditions, with dissolved inorganic nitrogen increasing and microbial biomass nitrogen decreasing with reduced soil volumetric water content. Carbon stocks were not sensitive to drought but were greater under E. viridis patches. Additionally, we found that under E. viridis, there was a negative relationship between dissolved inorganic nitrogen and microbial biomass nitrogen, suggesting that drought-induced increases in dissolved inorganic nitrogen may be due to declines in nitrogen uptake from microbes and plants alike. This work suggests that perennial grass plant-soil feedbacks are more vulnerable to both short-term (seasonal) and long-term (multiyear) drought events than shrubs, which can impact the future trajectory of dryland mixed shrub grassland ecosystems as drought frequency and intensity will likely continue to increase with ongoing climate change.

Climate and Land Use Changes Impact the Future of European Amphibian Functional Diversity

Climate and land use changes drive shifts in species distributions, causing variations in species richness. Yet the influence of shifts in species distributions on functional diversity at broad spatial scales remains uncertain. Here, we explored the potential effect of climate and land use changes on the functional diversity of European amphibian assemblages from the present to 2050, along with their effect on species richness. We performed species distribution modelling using a scenario of climate and land use change to estimate current and future potential distributions of 73 species. We estimated functional diversity using morphological and ecological functional traits. Our results highlight the intricate effects of climate and land use changes on taxonomic and functional diversity of amphibians. A climate-induced northward expansion of amphibians is anticipated, with temperature, precipitation, and forest cover prominently shaping future assemblages. Species expected to have shrinking ranges (n = 35) tend to mature sexually at a later age, produce fewer offspring per reproductive event, and live at higher maximum altitudes compared to species expected to expand (n = 38). Furthermore, trait composition changes are expected to exceed predictions based solely on species richness. These changes will vary geographically, with northern regions likely experiencing substantial increases in functional richness and functional redundancy, i.e., the coexistence of species with similar functional roles. Our findings underscore that functional diversity changes might serve as an early warning signal to assess human impacts on biodiversity.

Ants and predators cope with pest pressures by interacting with the surrounding vegetation at low spatial scales

AbstractBiological control of pests can be enhanced by the presence of semi‐natural habitats within agricultural landscapes. However, this assumption remains controversial due to inconsistencies related to the type of agroecosystems and the natural enemies studied. Within olive orchards, there is a lack of information regarding the interaction among natural enemies and their relation with habitat structure to control pests at the landscape scale. Here, we investigate the effects of the natural habitat on the pest, pest damage and the interaction of pests and natural enemies – using a trophic guild approach, in organic olive orchards. For this, we decomposed the natural habitats into vegetation structures and analysed their effects with a multi‐scale perspective. Our results show that (1) greater proportions of natural habitats increase the abundance of ants (omnivores) and predators and diminish pest pressures – reducing the impact of Prays oleae on olive fruits. (2) Vegetation structures within natural habitats were grouped, based on their effects, into three main vegetation groups: grassland and forest, scrublands and olive trees. However, the dense scrubland and the dense forest improve the abundance of natural enemies that are linked to pest damage the most. (3) Prays oleae increases in landscapes dominated by low numbers of patches that are highly aggregated. Conversely, ants and predators increased in landscapes dominated by high numbers of patches that have a less edge‐resembling shape. (4) Within the olive canopy, the abundance of lacewing larvae and salticid spiders is related to lower pest damage and a reduction in P. oleae adults respectively. However, when ants and predators interact with the natural habitat, they can cope with pest pressures without the need for high abundances, supporting ‘the more‐effective natural enemy hypothesis’ in agroecosystems.

Multispecies macrozoobenthic seasonal bioturbation effect on sediment erodibility

Bioturbation in estuarine environments describes all sediment reworking processes implied in sediment transport. However, modelling at large spatial and temporal scales remains a challenge because of the need to consider the fauna at the community level, and because animal behaviour is highly seasonal with non-linear effects of macrofauna functional trait interactions. Bioturbation processes can be linked to the activity of organisms, based on the principle of energy ecology, linking the metabolic rate to the erodibility of a sediment colonised by benthic fauna. This study investigates this postulate by evaluating the erodibility parameters of a sediment subjected to: i) the bioturbation under seasonal temperature variations; ii) the synergistic bioturbation of different species. The experimental design consisted of: i) three temperature levels (winter, spring and summer), ii) three types of species duos (Cerastoderma edule and Macoma balthica; Scrobicularia plana and Hediste diversicolor; Corophium volutator and Peringia ulvae) at 4 different relative densities. Two successive experiments were carried out on the same individuals: measurement of oxygen consumption of fauna then measurement of the erodibility of the colonised sediment in a flume. The oxygen consumption confirmed that the metabolic rate is a good model of the fauna respiration, regardless of species. The erosion results indicated that the metabolic rate in the case of the fluff layer resuspension is an interesting descriptor for 1) the assessment of the bioturbation under variable temperatures and 2) the integration of the two different bioturbator species that could co-occur in the same habitat. In contrast, the effect of bioturbation on the mass sediment erosion threshold cannot be easily modelled by using the metabolic rate and the classification in functional groups is required. Bioturbation models of the fluff layer using metabolic rate is a promising tool for modelling the effects of faunal communities on sediment transport at the scale of an estuary and over the long term, even projected in the context of global warming.

High-Resolution Rainfall Estimation Using Ensemble Learning Techniques and Multisensor Data Integration

In Indonesia, the monitoring of rainfall requires an estimation system with a high resolution and wide spatial coverage because of the complexities of the rainfall patterns. This study built a rainfall estimation model for Indonesia through the integration of data from various instruments, namely, rain gauges, weather radars, and weather satellites. An ensemble learning technique, specifically, extreme gradient boosting (XGBoost), was applied to overcome the sparse data due to the limited number of rain gauge points, limited weather radar coverage, and imbalanced rain data. The model includes bias correction of the satellite data to increase the estimation accuracy. In addition, the data from several weather radars installed in Indonesia were also combined. This research handled rainfall estimates in various rain patterns in Indonesia, such as seasonal, equatorial, and local patterns, with a high temporal resolution, close to real time. The validation was carried out at six points, namely, Bandar Lampung, Banjarmasin, Pontianak, Deli Serdang, Gorontalo, and Biak. The research results show good estimation accuracy, with respective values of 0.89, 0.91, 0.89, 0.9, 0.92, and 0.9, and root mean square error (RMSE) values of 2.75 mm/h, 2.57 mm/h, 3.08 mm/h, 2.64 mm/h, 1.85 mm/h, and 2.48 mm/h. Our research highlights the potential of this model to accurately capture diverse rainfall patterns in Indonesia at high spatial and temporal scales.

The use of conceptual models to structure stock assessments: A tool for collaboration and for “modelling what to model”

Conceptual models are simplified representations of the main components and processes of a dynamic system, the mechanisms by which they are related, and the ways they are observed (i.e., the data generating processes). Constructing a conceptual model (CM) should be the first step when planning a new stock assessment or updating previous assessments, because it can improve the modelling process by guiding the workflow and “modelling what to model”. CMs should be built by summarizing information about a system while also proposing hypotheses or assumptions about the uncertainties and unknown aspects. Several steps are necessary to build a CM: 1) gather known information about the species and the fisheries that interact with it, 2) state the objectives of the stock assessment, 3) define the spatial scale, 4) define the temporal scale, and 5) outline components and processes of the system (biological, fisheries and observation processes) and what drives them. Initial draft CMs should be based on the best available science and constructed using the fundamental principles of ecology, socioecology, fisheries and other relevant sciences. CMs offer a framework for integrating knowledge across domains, and benefit from an elicitation process. The elicitation process is a set of deliberate activities (e.g., workshops) that allow other experts and relevant parties to contribute with their knowledge to enrich draft CMs. CMs are not static entities but rather dynamic constructs that can identify future research directions and evolve to incorporate new insights and knowledge. Fisheries systems for highly migratory pelagic species in the Pacific Ocean (north Pacific Albacore tuna, eastern Pacific Dorado, and south Pacific Swordfish) are used as examples to illustrate how to develop CMs, and demonstrate improvements to the subsequent assessment models following development of the CMs.

Graph-theoretic modeling reveals connectivity hotspots for herbivorous reef fishes in a restored tropical island system

ContextSeascape connectivity refers to how the spatial configuration of marine habitats facilitates or hinders the movement of organisms, nutrients, materials or energy. Predicting and ranking potential connectivity among habitat patches for coral reef fishes helps to understand how reef fishes could utilize and connect multiple habitat types through the flow of nutrients, energy and biomass across the wider seascape during foraging movements.ObjectivesTo advance a spatially explicit understanding of connectivity linkages within a tropical atoll system by modeling, mapping and quantifying potential seascape connectivity for two locally abundant herbivorous reef fish species, the parrotfish, Chlorurus spilurus (pahoro hohoni or pa’ati pa’apa’a auahi), and the surgeonfish, Acanthurus triostegus (manini).MethodsWe applied a two-step modeling approach by first mapping habitat suitability for the focal species. A graph-theoretic modeling technique was then applied to model and measure the contribution of benthic habitat patches to species-specific potential connectivity within the seascape.ResultsHabitat suitability was higher and less fragmented for C. spilurus than for A. triostegus. Potential ecological connectivity estimates for C. spilurus were higher across the entire seascape, with differences between species likely driven by local-scale benthic habitat patch configuration and species home ranges. Hotspots of ecological connectivity across the atoll were mapped for both species.ConclusionsDespite advances in the application of graph-theoretic techniques in the coastal environment, few marine conservation and restoration measures currently integrate spatial information on ecological connectivity. This two-step spatial modeling approach holds great potential for rapid application of connectivity modeling at multiple spatial scales, which may predict ecological responses to conservation actions including active habitat restoration.