Habitat Overlap Research Articles

A matter of size: Does habitat use depend on body size in Amazonian small-stream shrimp species?

ABSTRACT Natural selection is a key driver of organism size and shape, so resource use often depends on individual size. Among populations and assemblages there is overwhelming evidence that size- or stage-specific effects on niche occur mainly in habitat and food dimensions. A 2019 study by E. P. Silva and others, “Habitat segregation among freshwater shrimp species in an Amazonian rainforest stream system,” showed that Amazonian small-stream shrimp species show only slight habitat segregation at the scale of 50 m stream reaches, but that study did not take into account possible effects of intraspecific and interspecific differences in body size on habitat selection. We investigated through nighttime observations if conspecific shrimp of different sizes overlap in habitat use and whether heterospecific individuals of similar sizes differ in habitat use. Generalized linear mixed models were used to test possible relationships between body size and habitat features, and multivariate linear analysis and latent-variable model-based ordination were used to test for intraspecific and interspecific differences in habitat use. Mean frequency of use of habitat features differed among shrimp of different sizes and species, but use of habitat components strongly overlapped. Interspecific habitat overlap was greater among small individuals than large individuals. Our results indicate that size is not a major driver of habitat segregation in shrimp populations and assemblages, although it provides evidence of subtle ontogenetic shifts in habitat use by conspecifics of different sizes as well as differences between individuals of different species with similar sizes.

Habitat and trophic niche overlap among juvenile black sea bass, tautog, and cunner: interspecific interactions amid a species geographic range expansion

Juvenile black sea bass Centropristis striata populations are increasing in southern New England estuaries of the northeastern USA with possible trophodynamic effects on labrid species: tautog Tautoga onitis and cunner Tautogolabrus adspersus. In this study, we examined the abundance, size-structure, and feeding ecology of juvenile sea bass and labrids in Narragansett Bay (Rhode Island, USA) from June to October in 2018 and 2019 and evaluated potential interspecific competition using habitat, diet, and isotopic niche overlap indices. Juveniles (age-0+) of each fish species spatiotemporally co-occurred in shallow, polyhaline habitats throughout the estuary. Age-0 cohorts were numerically dominant across species and initially recruited to the study area in July (minimum total length, TL = 15-20 mm), reached peak abundances in mid- to late summer (maximum abundances = 12-140 fish 100 m-2), and emigrated from field sites in October (maximum TL = 85-96 mm). Stomach content and stable isotope (δ15N and δ13C) analyses determined that focal fishes were generalist carnivores that foraged in bentho-pelagic food webs. Fishes also overlapped in their respective ambit and core isotopic niche space, but interspecific dietary overlap was size-dependent. Dietary overlap was most pronounced between sea bass ≤49 mm TL and labrids ≤59 mm TL due to their mutual reliance on gammarid and caprellid amphipods. Ontogenetic dietary shifts then resulted in food niche segregation, such that sea bass 50-139 mm TL consumed decapod crustaceans and fish, whereas labrids 60-181 mm TL mainly fed on amphipods, worms, bivalves, and turf-associated biota, i.e. bryozoans, hydroids, and seaweeds. Habitat and trophic niche overlap between early juvenile sea bass and labrids purportedly have not caused opposite population trajectories or food resource limitation in Narragansett Bay, indicating an absence of exploitative competition. Alternatively, realized competition between species may be too spatiotemporally restricted to alter their population dynamics. Continuous monitoring of the sea bass’s bio-ecological effects in southern New England estuaries is warranted, however, given their recent range expansion and increasing abundances at northern latitudes.

Habitat Overlap and Resource Selection Between Native Blackbuck and Invasive Feral-horse at Point Calimere Wildlife Sanctuary, Southern India

Habitat Overlap and Resource Selection Between Native Blackbuck and Invasive Feral-horse at Point Calimere Wildlife Sanctuary, Southern India

Ontogenetic habitat partitioning among four shark species within a nursery ground

Context Nursery areas provide refuge from predators, rich foraging grounds, and physical conditions conducive to growth and development of juvenile inhabitants. Specifically, the Mississippi Sound in the northern Gulf of Mexico is likely a nursery ground for multiple large and small coastal sharks. Aims and methods Using over a decade of shark survey catch data, we employed habitat modelling approaches to identify preferred environmental conditions and spatial distribution, and quantify core habitat overlap within the Mississippi Sound for young-of-year (YOY), juvenile and adult life stages of four coastal shark species. Results YOY Atlantic sharpnose (Rhizoprionodon terraenovae), blacktip (Carcharhinus limbatus) and finetooth (Carcharhinus isodon) sharks showed a preference for a combination of shallow, warm, low salinity, low dissolved oxygen and turbid waters. Corresponding to shared environmental preferences, spatial distributions of YOY sharks showed a high degree of overlap, particularly in the northern portion of the Mississippi Sound where few adult sharks were observed, suggesting that these life stages partition themselves to avoid predation. Conclusion and implications With a continued rise in US coastal shark populations, we hope this study can help further refine essential fish habitat for these coastal species and provide a framework analysis that can be used to understand habitat partitioning in other regions.

Spatiotemporal predictions of the alternative prey hypothesis: Predator habitat use during decreasing prey abundance

AbstractThe alternative prey hypothesis supposes that predators supported by a primary prey species will shift to consume alternative prey during a decrease in primary prey abundance. The hypothesis implies that during declines of one prey species, a predator modifies their behavior to exploit a secondary, or alternative, species. Despite occurring in many systems, the behavioral mechanisms (e.g., habitat selection) allowing predators to shift toward alternative prey during declines in the abundance of their primary prey are poorly understood. We evaluated habitat selection and use by a generalist predator with respect to two prey species during a dramatic decrease in the abundance of primary prey. Further, we evaluated how spatial variation in access to primary prey affected habitat selection, and assessed similarity and overlap between habitats used by each prey species. Coyotes (Canis latrans) exhibited decreasing selection for cottontail rabbits (Sylvilagus spp.; primary prey) during population decreases but did not shift habitat selection toward neonate mule deer (Odocoileus hemionus; alternative prey). Use of rabbit habitat remained high even during historically low rabbit abundance, while mule deer habitat was used in proportion to its availability. Coyotes seemingly do not make large shifts in habitat selection toward alternative prey following spatial and temporal decreases in the abundance of primary prey, but instead, take advantage of habitat overlap to facilitate prey‐switching behavior. Our work extends previous research conducted under the alternative prey hypothesis by explicitly evaluating the influence of habitat overlap between prey species and variation in access to prey habitat as factors affecting prey‐switching behaviors in predators.

Field assessment of parasitism on the New Zealand endemic Nyctemera annulata by Cotesia urabae: Can non-target impacts be ruled out?

Cotesia urabae is biological control agent (BCA) that was introduced in New Zealand in 2011 against the Eucalyptus defoliating lepidopteran pest Uraba lugens. During pre- and post-release host specificity testing, one non-target moth, the New Zealand endemic Nyctemera annulata, was occasionally attacked, albeit a poor physiological host for C. urabae development. With the BCA now established in the New Zealand environment, we undertook a sentinel larval trial in the field, which included artificial releases of C. urabae, to assess non-target impacts in habitats, either with or without the presence of the target host and its host plant. Approximately two-thirds of all sentinel larvae released in the field were successfully recovered and reared in the laboratory to obtain parasitism. In the overlapping choice habitat (i.e., both target and non-target hosts present along with their host plants), the BCA C. urabae was recovered from 22.3% and 3.1% of target and non-target larvae, respectively. In the habitat devoid of Eucalyptus and its target larvae, C. urabae parasitised only 0.2% of the non-target, suggesting the BCA had immediately dispersed from release sites devoid of host cues. The non-target N. annulata was at greater risk of attack where the habitat overlap was most significant. This provided invaluable data to calibrate non-target risk models. Most importantly, the generalist parasitoids Diolcogaster perniciosus and Meteorus pulchricornis (Braconidae), which were also recovered in our field trials, had a much greater impact upon N. annulata than the specialist BCA.

Aquatic insects differentially affect lake sturgeon larval phenotypes and egg surface microbial communities.

Documentation of how interactions among members of different stream communities [e.g., microbial communities and aquatic insect taxa exhibiting different feeding strategies (FS)] collectively influence the growth, survival, and recruitment of stream fishes is limited. Considerable spatial overlap exists between early life stages of stream fishes, including species of conservation concern like lake sturgeon (Acipenser fulvescens), and aquatic insects and microbial taxa that abundantly occupy substrates on which spawning occurs. Habitat overlap suggests that species interactions across trophic levels may be common, but outcomes of these interactions are poorly understood. We conducted an experiment where lake sturgeon eggs were fertilized and incubated in the presence of individuals from one of four aquatic insect FS taxa including predators, facultative and obligate-scrapers, collector-filterers/facultative predators, and a control (no insects). We quantified and compared the effects of different insect taxa on the taxonomic composition and relative abundance of egg surface bacterial and lower eukaryotic communities, egg size, incubation time to hatch, free embryo body size (total length) at hatch, yolk-sac area, (a measure of resource utilization), and percent survival to hatch. Mean egg size varied significantly among insect treatments. Eggs exposed to predators had a lower mean percent survival to hatch. Eggs exposed to predators had significantly shorter incubation periods. At hatch, free embryos exposed to predators had significantly smaller yolk sacs and total length. Multivariate analyses revealed that egg bacterial and lower eukaryotic surface community composition varied significantly among insect treatments and between time periods (1 vs 4 days post-fertilization). Quantitative PCR documented significant differences in bacterial 16S copy number, and thus abundance on egg surfaces varied across insect treatments. Results indicate that lethal and non-lethal effects associated with interactions between lake sturgeon eggs and free embryos and aquatic insects, particularly predators, contributed to lake sturgeon trait variability that may affect population levels of recruitment.

A comprehensive assessment of fungal communities in various habitats from an ice-free area of maritime Antarctica: diversity, distribution, and ecological trait

BackgroundIn the ice-free area of maritime Antarctica, fungi are the essential functioning group in terrestrial and marine ecosystems. Until now, no study has been conducted to comprehensively assess fungal communities in various habitats in Antarctica. We aimed to characterize fungal communities in the eleven habitats (i.e., soil, seawater, vascular plant, dung, moss, marine alga, lichen, green alga, freshwater, feather) in the Fildes Region (maritime Antarctica) using next-generation sequencing.ResultsA total of 12 known phyla, 37 known classes, 85 known orders, 164 known families, 313 known genera, and 320 known species were detected. Habitat specificity rather than habitat overlap determined the composition of fungal communities, suggesting that, although fungal communities were connected by dispersal at the local scale, the environmental filter is a key factor driving fungal assemblages in the ice-free Antarctica. Furthermore, 20 fungal guilds and 6 growth forms were detected. Many significant differences in the functional guild (e.g., lichenized, algal parasite, litter saprotroph) and growth form (e.g., yeast, filamentous mycelium, thallus photosynthetic) existed among different habitat types.ConclusionThe present study reveals the high diversity of fungal communities in the eleven ice-free Antarctic habitats and elucidates the ecological traits of fungal communities in this unique ice-free area of maritime Antarctica. The findings will help advance our understanding of fungal diversity and their ecological roles with respect to habitats on a neighbourhood scale in the ice-free area of maritime Antarctica.

Evaluating the Suitability and Overlap of Resting and Path Habitats of Giant Pandas in the Wanglang Nature Reserve

Habitat fragmentation threatens the survival of giant panda (Ailuropoda melanoleuca); hence, it is vital to protect its habitat. However, a lack of detailed understanding of different functional habitats and their relationships restricts the protective effect. To reveal the relationship between different functional habitats, we distinguished and investigated giant pandas’ resting and path sites and evaluated the suitability patterns and overlap of resting and path habitats in the Wanglang Nature Reserve using MAXENT and overlay methods. A total of 28 resting sites and 30 path sites were used in this study. The results showed that the areas of suitable resting and path habitats were 42.03 km2 and 28.52 km2, respectively, and were fragmented due to the existence of roads. A total of 27.81 km2 of suitable habitat overlapped, indicating many areas have the dual attributes of suitable resting and path habitats for giant pandas. There were almost no suitable resting and path habitats within 200 m and 300 m from roads, respectively. Therefore, measures should be taken to restore the unsuitable habitats distributed in the roadside area and connect the fragmented habitat patches. The indicators and methods used in this study can be considered in studying different functional giant panda habitats and their relationships.

Conservation prioritization through combined approach of umbrella species selection, occupancy estimation, habitat suitability and connectivity analysis of kingfisher: A study from an internationally important wetland complex (Ramsar site) in India

Assessment of occupancy status, as well as projection of suitable habitats and connectivity of wetland indicator species, and thereby identification of potential conservation umbrella and projection of conservation priority areas are often considered important for wetland conservation. Kingfishers are wetland indicators and suffer from habitat degradation due to world-wide destruction of wetlands. Therefore, they can be considered potential candidates for conservation intervention. The present knowledge about the spatial distribution of suitable areas and habitat connectivity of kingfishers at a landscape level is non-existent. We conducted extensive surveys and recorded four kingfisher species in East Kolkata Wetlands (EKW; Ramsar site No. 1208; ∼125 km2). The occupancy estimates were highest for White-throated kingfisher (Halcyon smyrnensis, WTK), followed by common kingfisher (Alcedo atthis, CK), stork-billed kingfisher (Pelargopsis capensis, SBK) and lowest for pied kingfisher (Ceryle rudis, PK). WTK has the highest amount of suitable areas followed by CK, PK and SBK. The spatial overlap of suitable habitats showed that SBK is the potential umbrella species and therefore provides conservation benefits to other kingfisher species and eventually to the EKW. In addition to water areas, emergent vegetation, crop lands and tree cover are other important habitats for kingfishers. The connectivity analyses revealed that suitable habitats were disjunct and are under various anthropogenic threats. Therefore, we need to protect suitable habitats and connectivity between them. Finally, we identified conservation priority areas. Conservation intervention on these high priority zones will not only be beneficial for kingfishers, but also for other avifauna having similar resource requirements as well as the wetland parse.

A long‐term shift in the summer distribution of Hector’s dolphins is correlated with an increase in cruise ship tourism

Abstract Before the 2020 COVID‐19 pandemic, cruise ship tourism had been one of the fastest growing segments of global tourism, presenting a range of potential impacts. At Akaroa Harbour, Aotearoa New Zealand, the number of annual cruise ship visits more than quadrupled following earthquake damage to Ōtautahi Christchurch's Lyttelton Port in 2011. Akaroa Harbour is an area of core use for endangered and endemic Hector’s dolphins (Cephalorhynchus hectori). Dolphins here are exposed to some of the highest levels of cetacean tourism in Aotearoa New Zealand. Relationships were examined between growth in cruise ship visits, as well as tours focused specifically on dolphins, and long‐term trends in summer distribution of Hector’s dolphins at Akaroa Harbour, from 2000 to 2020. Core use areas for Hector’s dolphins within the harbour were quantified via kernel density estimation using data from 2,335 sightings from over 8,000 km of standardized survey effort. Data were allocated into four periods based on varying levels of tourism. Dolphin habitat preference varied over time, with the greatest change occurring between 2005–2011 and 2012–2015. When comparing these periods, the spatial overlap of core habitat was less than 24%. Dolphin distribution shifted towards the outer harbour after 2011 and has remained relatively consistent since. The observed shift in distribution coincided with the more than fourfold increase in annual cruise ship visits to Akaroa Harbour. Several pressures related to cruise ship tourism are likely to have influenced habitat preferences of dolphins. Further investigation into causal factors of the observed shift is warranted. In the wake of the COVID‐19 pandemic, the future of cruise ship and wildlife tourism is in flux. Our findings suggest that the future re‐development of this industry should follow a precautionary approach, with the onus on industry to provide evidence of sustainability before proceeding.

On the edge: habitat restoration priorities for three critically endangered bird species on Sangihe, Indonesia

Remnant forests on the small Wallacean island of Sangihe north of Sulawesi hold the entire ranges of more critically endangered (CR) bird species than any other comparable area on earth. We develop habitat association models for three of these CR species to identify critical habitat features as well as areas where habitat falls slightly short of suitability, and to determine whether another area of forest away from the largest block might be suitable as an insurance site for a translocated population. Hopes for all three species appear almost totally pinned to forest within a 13 km2 area of the Sahendaruman crater, with virtually no near‐suitable habitat away from this site. There is, however, little overlap in habitats between one CR species and the other two: cerulean flycatcher Eutrichomyias rowleyi is associated with mature streamside forest with full canopy cover, lianas, and mid‐level growth, while Sangihe whistler Coracornis sanghirensis and Sangihe golden bulbul Hypsipetes platenae are restricted to ridgetop forest with full canopy cover and large trees. We pinpoint small areas (around 5 km2) of forest in the crater that are already suitable or can be made so with habitat management, and these are absolute priorities for conservation action. We show how habitat characteristics identified within models might be enhanced, and how features, especially certain tree species, can be used as indicators of future habitat improvement.

Suitable Habitats of Chrysolophus spp. Need Urgent Protection from Habitat Fragmentation in China: Especially Suitable Habitats in Non-Nature Reserve Areas.

Simple SummaryWild populations of C. pictus and C. amherstiae have been decreasing due to habitat fragmentation and long-term uncontrolled poaching. To support the Chrysolophus spp.’s conservation, we simulated the potential distribution of the two species in China, calculated the patch fragmentation index of suitable habitats of Chrysolophus spp. in nature reserve areas and non-nature reserve areas, and analyzed the habitat status of C. pictus and C. amherstiae in China. Compared with the previous studies, their habitat areas have been reduced. In addition, most of the suitable habitats were not in nature reserves and were highly fragmented. We offer recommendations for the Chinese government to formulate conservation schemes for the Chrysolophus spp. population in the future.Over the past few years, the wild population of Chrysolophus spp. has decreased remarkably. Habitat fragmentation is a significant cause for this serious threat to the survival of Chrysolophus spp. population. In order to further understand the distribution of potentially suitable habitats of Chrysolophus spp., we used the maximum entropy model to predict the potentially suitable habitats of C. pictus and C. amherstiae in China based on the known distribution. According to the prediction results of the model, we calculated the landscape pattern index to compare the fragmentation of the two species’ potential suitable habitats in nature reserves and non-nature reserves. The results showed that the potentially suitable habitat for Chrysolophus spp. only accounted for a small area of China. The suitable habitats for C. pictus were mainly in Sichuan, Shaanxi, Hubei, and other provinces, and the model predicts a total area of 359,053.06 km2. In addition, the suitable habitats for C. amherstiae were mainly distributed in the three-parallel-river area, with a potential total area of 215,569.83 km2. The model also showed that there was an overlap of suitable habitats between the two species in the western edge of the Sichuan Basin. Previously, hybrids of the two pheasants have already been found in this same overlapping area predicted by the model. The landscape pattern index showed that in the potentially suitable habitat for Chrysolophus spp., the fragmentation of non-nature reserve areas was higher than that of nature reserve areas. The results revealed the distribution of potentially suitable habitats for Chrysolophus spp. in China and highlighted that the suitable habitats in non-nature reserve areas were in urgent need of conservation, thereby providing a key reference for the conservation of the Chrysolophus spp. population in the future.

Doru luteipes (Dermaptera: Forficulidae) and Orius insidiosus (Hemiptera: Anthocoridae) as Nocturnal and Diurnal Predators of Thrips.

Thrips (Thysanoptera, Thripidae) are pests of several crops and their chemical control is mainly hindered by their thigmotactic habits, which in turn allows the use of biological control agents with similar habits. Orius (Hemiptera: Anthocoridae) are effective control agents for thrips and are commercialized in many countries. Habitat overlap exists between Doru luteipes (Scudder) (Dermaptera: Forficulidae) and thrips, making D. luteipes a potential predator in the control of these insects. Our goals were to confirm the predatory ability of D. luteipes when exposed to thrips, Caliothrips phaseoli (Hood), and to evaluate the interaction between D. luteipes and Orius insidiosus Say for the control of thrips using behavioral and feeding preference tests. The ability of D. luteipes and O. insidiosus to prey on thrips at all stages was tested by predation bioassays; adults of D. luteipes consumed 210.9 ± 23.2 thrips per day, while adults of O. insidiosus consumed 32.4 ± 3.6 thrips per day. Intraguild predation was absent, and the predatory behavior feeding of the two predatory species was not altered in the presence of the other predator. In addition, these predators forage at different times-O. insidiosus during the day and D. luteipes at night, indicating that both predators do not interact negatively, allowing the use of both in a biological pest control program for thrips.

Co-occurrence, ecological profiles and geographical distribution based on unique molecular identifiers of the common freshwater diatoms Fragilaria and Ulnaria

Diatom taxonomy has evolved in recent years, with many new species described and new approaches such as molecular genetics showing the existence of cryptic diversity within currently accepted species. This cryptic diversity is not well understood even for common freshwater genera such as Fragilaria and Ulnaria. The purpose of our study was to define taxon-specific ecological profiles and geographical distributions for unique molecular identifiers (amplicon sequence variants, ASVs) linked to curated taxonomy for these genera. Our goal is to contribute to the development of ecological assessment methods, and to the understanding why we often observe so many diatom species co-occurring in a single sample. We filtered a large (770 samples) metabarcoding dataset with linked environmental data covering several countries in Europe for genetic variants (ASVs) assigned to currently accepted species of our target genera. We studied the geographical distribution of the ASVs, and tested for ASV-pair co-occurrence. We modelled ASV-specific preferences for pH, alkalinity, total nitrogen, total phosphorus and conductivity, and analysed their preference for lakes or streams as habitat. Our study confirmed that there seems to be no general geographical barrier for the distribution of freshwater benthic diatom ASVs in Europe, but that dispersal is not rapid enough to hide historical events. The Fragilaria and Ulnaria ASVs in our study showed considerable overlap in geographical distribution, habitat and ecological preferences. We found evidence that only large differences in preferences for the analysed water chemistry variables prevented the co-occurrence of ASVs at the same sites. Instead, Fragilaria and Ulnaria ASVs co-occurred frequently in samples. We found subtle differences in ecological preferences for some ASV pairs, which might in part explain the co-occurrence by the avoidance of direct competition. However, the great overlap in distribution and ecological preferences suggests that other factors not studied here were also responsible for the observed co-occurrences and high richness of ASVs found at many sites. To our knowledge, we are the first to use ASVs in combination with a curated taxonomy to understand co-occurrence, specific ecological profiles and large-scale geographical distribution for unique identifiers not biased by the quality of reference databases, clustering methods, or non-harmonized morphological identification. Thus, our results can now be used in subsequent projects to interpret ASV occurrences, e.g. for development of ecological assessment methods.

Forecasting shifts in habitat suitability of three marine predators suggests a rapid decline in inter-specific overlap under future climate change.

Understanding how environmental and climate change can alter habitat overlap of marine predators has great value for the management and conservation of marine ecosystems. Here, we estimated spatiotemporal changes in habitat suitability and inter‐specific overlap among three marine predators: Baltic gray seals (Halichoerus grypus), harbor seals (Phoca vitulina), and harbor porpoises (Phocoena phocoena) under contemporary and future conditions. Location data (>200 tagged individuals) were collected in the southwestern region of the Baltic Sea; one of the fastest‐warming semi‐enclosed seas in the world. We used the maximum entropy (MaxEnt) algorithm to estimate changes in total area size and overlap of species‐specific habitat suitability between 1997–2020 and 2091–2100. Predictor variables included environmental and climate‐sensitive oceanographic conditions in the area. Sea‐level rise, sea surface temperature, and salinity data were taken from representative concentration pathways [RCPs] scenarios 6.0 and 8.5 to forecast potential climate change effects. Model output suggested that habitat suitability of Baltic gray seals will decline over space and time, driven by changes in sea surface salinity and a loss of currently available haulout sites following sea‐level rise in the future. A similar, although weaker, effect was observed for harbor seals, while suitability of habitat for harbor porpoises was predicted to increase slightly over space and time. Inter‐specific overlap in highly suitable habitats was also predicted to increase slightly under RCP scenario 6.0 when compared to contemporary conditions, but to disappear under RCP scenario 8.5. Our study suggests that marine predators in the southwestern Baltic Sea may respond differently to future climatic conditions, leading to divergent shifts in habitat suitability that are likely to decrease inter‐specific overlap over time and space. We conclude that climate change can lead to a marked redistribution of area use by marine predators in the region, which may influence local food‐web dynamics and ecosystem functioning.

Integrated species distribution models reveal spatiotemporal patterns of human-wildlife conflict.

To mitigate human-wildlife conflict it is imperative to know where and when conflict occurs. However, standard methods used to predict the occurrence of human-wildlife conflict often fail to recognize how a species distribution likely limits where and when conflict may happen. As such, methods that predict human-wildlife conflict could be improved if they could identify where conflict will occur relative to species' underlying distribution. To this end, we used an integrated species distribution model that combined presence-only wildlife complaints with data from a systematic camera trapping survey throughout Chicago, Illinois. This model draws upon both data sources to estimate a latent distribution of species; in addition, the model can estimate where conflict is most likely to occur within that distribution. We modeled the occupancy and conflict potential of coyote (Canis latrans), Virginia opossum (Didelphis virginiana), and raccoon (Procyon lotor) as a function of urban intensity, per capita income, and home vacancy rates throughout Chicago. Overall, the distribution of each species constrained the spatiotemporal patterns of conflict throughout the city of Chicago. Within each species distribution, we found that human-wildlife conflict was most likely to occur where humans and wildlife habitat overlap (e.g., featuring higher-than-average canopy cover and housing density). Furthermore, human-wildlife conflict was most likely to occur in high-income neighborhoods for Virginia opossum and raccoon, despite the fact that those two species have higher occupancy in low-income neighborhoods. As such, knowing where species are distributed can inform guidelines on where wildlife management should be focused, especially if it overlaps with human habitats. Finally, because this integrated model can incorporate data that have already been collected by wildlife managers or city officials, this approach could be used to develop stronger collaborations with wildlife management agencies and conduct applied research that will inform landscape-scale wildlife management.

Data Quality Influences the Predicted Distribution and Habitat of Four Southern-Hemisphere Albatross Species

Few studies have assessed the influence of data quality on the predicted probability of occurrence and preferred habitat of marine predators. We compared results from four species distribution models (SDMs) for four southern-hemisphere albatross species, Buller’s (Thalassarche bulleri), Campbell (T. impavida), grey-headed (T. chrysostoma), and white-capped (T. steadi), based on datasets of differing quality, ranging from no location data to twice-daily locations of individual birds collected by geolocation devices. Two relative environmental suitability (RES) models were fit using minimum and maximum preferred and absolute values for each environmental variable based on (1) monthly 50% kernel density contours and background environmental data, and (2) primary literature or expert opinion. Additionally, two boosted regression tree (BRT) models were fit using (1) opportunistic sightings data, and (2) geolocation data from bird-borne electronic tags. Using model-specific threshold values, habitat was quantified for each species and model. Model variables included distance from land, bathymetry, sea surface temperature, and chlorophyll-a concentration. Results from both RES models and the BRT model fit with opportunistic sightings were compared to those from the BRT model fit using geolocation data to assess the influence of data quality on predicted occupancy and habitat. For all species, BRT models outperformed RES models. BRT models offer a predictive advantage over RES models by being able to identify relevant variables, incorporate environmental interactions, and provide spatially explicit estimates of model uncertainty. RES models resulted in larger, less refined areas of predicted habitat for all species. Our study highlights the importance of data quality in predicting the distribution and habitat of albatrosses and emphasises the need to consider the pros and cons associated with different levels of data quality when using SDMs to inform management decisions. Furthermore, we examine the overlap in preferred habitat predicted by each SDM with fishing effort. We discuss the influence of data quality on predicting the wide-scale distributions of pelagic seabirds and how these impacts could result in different protection measures.

Why the long teeth? Morphometric analysis suggests different selective pressures on functional occlusal traits in Plio-Pleistocene African suids

AbstractNeogene and Pleistocene African suids displayed convergent evolutionary trends in the third molar (M3) morphology, with increasingly elongated and higher crowns through time. While these features can prevent premature loss of masticatory functionality and potentially increase long-term reproductive success, changes in dental occlusal traits such as enamel complexity and thickness can also improve chewing efficiency and increase short-term energetic return. While both long-term and short-term benefits can contribute to the thriving of a lineage, the selective pressures associated with each category can be different. To examine how crown elongation correlates with these functional occlusal traits, we selected M3s ofKolpochoerus,Notochoerus, andMetridiochoerusfrom Kenya and South Africa, dated between 3.0 Ma and 0.4 Ma. To account for dental wear, we used micro-computed tomography imaging of unworn/slightly worn M3s to simulate wear progression within each tooth. We compared morphometric representatives of occlusal enamel complexity and thickness among the specimens following their respective wear trajectories. We found that M3 elongation correlates with higher occlusal complexity and thinner enamel inNotochoerusandMetridiochoeruslineages through time. InKolpochoerus, enamel complexity and thickness were generally maintained through time, despite M3 elongation. The differences in M3 morphometric trends suggest thatKolpochoeruslikely experienced a different set of selective pressures on functional occlusal traits compared withNotochoerusandMetridiochoerus. The shared evolutionary trends of M3 specialization amongNotochoerusandMetridiochoerussuggest similar selective pressures on their chewing efficiency and the possibility of a dietary niche overlap in more xeric habitats.

Global-Scale Environmental Niche and Habitat of Blue Shark (Prionace glauca) by Size and Sex: A Pivotal Step to Improving Stock Management

Blue shark (Prionace glauca) is amongst the most abundant shark species in international trade, however this highly migratory species has little effective management and the need for spatio-temporal strategies increases, possibly involving the most vulnerable stage or sex classes. We combined 265,595 blue shark observations (capture or satellite tag) with environmental data to present the first global-scale analysis of species’ habitat preferences for five size and sex classes (small juveniles, large juvenile males and females, adult males and females). We leveraged the understanding of blue shark biotic environmental associations to develop two indicators of foraging location: productivity fronts in mesotrophic areas and mesopelagic micronekton in oligotrophic environments. Temperature (at surface and mixed layer depth plus 100 m) and sea surface height anomaly were used to exclude unsuitable abiotic environments. To capture the horizontal and vertical extent of thermal habitat for the blue shark, we defined the temperature niche relative to both sea surface temperature (SST) and the temperature 100 m below the mixed layer depth (Tmld+100). We show that the lifetime foraging niche incorporates highly diverse biotic and abiotic conditions: the blue shark tends to shift from mesotrophic and temperate surface waters during juvenile stages to more oligotrophic and warm surface waters for adults. However, low productivity limits all classes of blue shark habitat in the tropical western North Atlantic, and both low productivity and warm temperatures limit habitat in most of the equatorial Indian Ocean (except for the adult males) and tropical eastern Pacific. Large females tend to have greater habitat overlap with small juveniles than large males, more defined by temperature than productivity preferences. In particular, large juvenile females tend to extend their range into higher latitudes than large males, likely due to greater tolerance to relatively cold waters. Large juvenile and adult females also seem to avoid areas with intermediate SST (~21.7-24.0°C), resulting in separation from large males mostly in the tropical and temperate latitudes in the cold and warm seasons, respectively. The habitat requirements of sensitive size- and sex-specific stages to blue shark population dynamics are essential in management to improve conservation of this near-threatened species.