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1.
J Fish Biol ; 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38663999

RESUMO

Combining fish tracking methods is a promising way of leveraging the strengths of each approach while mitigating their individual weaknesses. Acoustic telemetry provides presence information as the fish move within receiver range, eliminating the need for tag recovery. Archival tags, on the other hand, record environmental variables on tag retrieval, enabling continuous path reconstruction of a fish beyond coastal regions. This study capitalizes on the combination of both methods for geolocating pollack, Pollachius pollachius, an understudied species of the northeast Atlantic, where declining stocks are raising concern. Essential knowledge of population structure and connectivity between essential habitats is critically lacking and could help inform stock assessment and management. The aims of the study were (1) to evaluate the feasibility of double-tagging pollack, known for being challenging to tag, and (2) to track seasonal movements across the Channel to gain first insights into pollack spatial ecology. In 2022, an extensive network of acoustic receivers was been deployed in the Channel along the French, English, and Belgian coasts as part of the Fish Intel project. We tagged 83 pollack with acoustic transmitters, among which 48 were double-tagged with data storage tags. Post-tagging survival assessment, conducted on a subset of 35 individuals, revealed a successful procedure with a 97% short-term survival rate. By October 2023, the acoustic telemetry network detected 30 out of 83 pollack at least once, with no large-scale movements observed across the Channel. Presence in the network fluctuates seasonally, peaking in summer, particularly among immature fish. Integrating acoustic detections with temperature and depth time series in a geolocation model enabled trajectory reconstruction of 10 recaptured pollack, seven of which were detected by the network. This combined tracking approach revealed coastal movements along the coast of Brittany in France, highlighting the ecological significance of the Iroise Sea for pollack throughout the year, particularly in summer. The geolocation model also suggested movements towards the entrance of the western Channel. This study highlights the complementarity of acoustic telemetry and archival tagging in reconstructing fish movements in their natural environment. As data accumulate, these innovative tracking methods promise to continually unveil new insights into the spatial ecology of the understudied pollack, which is essential for the species' management.

2.
Glob Chang Biol ; 30(4): e17278, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38655695

RESUMO

The increasing frequency and severity of human-caused fires likely have deleterious effects on species distribution and persistence. In 2020, megafires in the Brazilian Pantanal burned 43% of the biome's unburned area and resulted in mass mortality of wildlife. We investigated changes in habitat use or occupancy for an assemblage of eight mammal species in Serra do Amolar, Brazil, following the 2020 fires using a pre- and post-fire camera trap dataset. Additionally, we estimated the density for two naturally marked species, jaguars Panthera onca and ocelots Leopardus pardalis. Of the eight species, six (ocelots, collared peccaries Dicotyles tajacu, giant armadillos Priodontes maximus, Azara's agouti Dasyprocta azarae, red brocket deer Mazama americana, and tapirs Tapirus terrestris) had declining occupancy following fires, and one had stable habitat use (pumas Puma concolor). Giant armadillo experienced the most precipitous decline in occupancy from 0.431 ± 0.171 to 0.077 ± 0.044 after the fires. Jaguars were the only species with increasing habitat use, from 0.393 ± 0.127 to 0.753 ± 0.085. Jaguar density remained stable across years (2.8 ± 1.3, 3.7 ± 1.3, 2.6 ± 0.85/100 km2), while ocelot density increased from 13.9 ± 3.2 to 16.1 ± 5.2/100 km2. However, the low number of both jaguars and ocelots recaptured after the fire period suggests that immigration may have sustained the population. Our results indicate that the megafires will have significant consequences for species occupancy and fitness in fire-affected areas. The scale of megafires may inhibit successful recolonization, thus wider studies are needed to investigate population trends.


A crescente frequência e gravidade dos incêndios causados pelo homem provavelmente terão efeitos deletérios na distribuição e persistência das espécies. Em 2020, mega incêndios no Pantanal brasileiro queimaram 43% do bioma e resultaram na mortalidade em massa da vida selvagem. Nós investigamos mudanças no uso ou ocupação do habitat para uma comunidade de oito espécies de mamíferos na Serra do Amolar, Brasil, após os incêndios de 2020, usando um conjunto de dados de armadilhas fotográficas instaladas no período pré e pós­fogo. Além disso, estimamos a densidade de duas espécies naturalmente marcadas, a onça­pintada Panthera onca e a jaguatirica Leopardus pardalis. Das oito espécies, seis (a jaguatirica, o cateto Dicotyles tajacu, o tatu­canastra Priodontes maximus, a cutia Dasyprocta azarae, o veado mateiro Mazama americana e a anta Tapirus terrestris) tiveram ocupação reduzida após os incêndios, e uma teve uso de habitat estável (a onça­parda, Puma concolor). O tatu­canastra apresentou o declínio mais acentuado na ocupação após os incêndios de 0,431 ± 0,171 para 0,077 ± 0,044. A onça­pintada foi a única espécie com uso crescente de habitat, de 0,393 ± 0,127 para 0,753 ± 0,085. A densidade da onça­pintada permaneceu estável ao longo dos anos (2,8 ± 1,3, 3,7 ± 1,3, 2,6 ± 0,85/100 km2), enquanto a densidade da jaguatirica aumentou de 13,9 ± 3,2 para 16,1 ± 5,2/100 km2. No entanto, o baixo número de onças­pintadas e jaguatiricas recapturadas após o período do fogo sugere que a imigração pode ter sustentado as populações. Nossos resultados indicam que os mega incêndios terão consequências significativas para a ocupação e resiliência das espécies nas áreas afetadas pelo fogo. A escala dos mega incêndios pode inibir uma recolonização bem­sucedida, pelo que são necessários estudos mais amplos para investigar as tendências populacionais.


Assuntos
Ecossistema , Animais , Brasil , Mamíferos/fisiologia , Dinâmica Populacional , Incêndios , Densidade Demográfica , Incêndios Florestais
3.
Ecol Evol ; 14(4): e11221, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38584772

RESUMO

Bottlenose dolphin (Tursiops) populations, also described as the Burrunan dolphins, consist of a resident population of approximately 150 individuals in Port Phillip Bay (PPB), Victoria. Previous reports indicate distribution across a small southern region of PPB; however, little is known about their full distribution patterns across the entire PPB region. Here, we investigate the spatiotemporal distribution of the Burrunan dolphins across four zones representative of PPB benthic habitats and bathymetry to gain a better understanding of the potential drivers of the population's habitat use. Port Phillip Bay, Victoria, Australia. One hundred and twenty-nine boat-based surveys were undertaken between March 2015 and August 2021, encompassing 181 sightings. Generalised linear models (GLMs) were used to investigate annual, seasonal and zonal variation. We found no variation in sighting frequencies between years. Austral summer and winter had a significantly higher sighting frequency than autumn. We found that Burrunan dolphins utilise the entire bay, further extending the species range, and show a significantly higher number of sightings in the southern zone than in any other zones. Overlaying dolphin sightings with known oceanographic characteristics within PPB, we found bathymetry and benthic habitats were potential drivers for the Burrunan dolphins distribution and habitat use within the bay, with the dolphins significantly favouring the 5-10 and 10-15 m contour depths. These results show a more widespread distribution across the bay than previously documented. We recommend expansion of the current marine protected areas in the north and south of the bay. This study has increased our understanding of the vital habitat for the Burrunan dolphin populations. By providing evidence-based conservation recommendations, we hope to improve and contribute to future research, conservation management plans and effective marine protected areas across PPB for the resident Burrunan dolphin population.

4.
Mov Ecol ; 12(1): 21, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38491373

RESUMO

BACKGROUND: Ecological and physical conditions vary with depth in aquatic ecosystems, resulting in gradients of habitat suitability. Although variation in vertical distributions among individuals provides evidence of habitat selection, it has been challenging to disentangle how processes at multiple spatio-temporal scales shape behaviour. METHODS: We collected thousands of observations of depth from > 300 acoustically tagged adult Chinook salmon Oncorhynchus tshawytscha, spanning multiple seasons and years. We used these data to parameterize a machine-learning model to disentangle the influence of spatial, temporal, and dynamic oceanographic variables while accounting for differences in individual condition and maturation stage. RESULTS: The top performing machine learning model used bathymetric depth ratio (i.e., individual depth relative to seafloor depth) as a response. We found that bathymetry, season, maturation stage, and spatial location most strongly influenced Chinook salmon depth. Chinook salmon bathymetric depth ratios were deepest in shallow water, during winter, and for immature individuals. We also identified non-linear interactions among covariates, resulting in spatially-varying effects of zooplankton concentration, lunar cycle, temperature and oxygen concentration. CONCLUSIONS: Our results suggest Chinook salmon vertical habitat use is a function of ecological interactions, not physiological constraints. Temporal and spatial variation in depth distributions could be used to guide management decisions intended to reduce fishery impacts on Chinook salmon. More generally, our findings demonstrate how complex interactions among bathymetry, seasonality, location, and life history stage regulate vertical habitat selection.

5.
Mar Pollut Bull ; 202: 116294, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38537499

RESUMO

Shipping is one of the largest industries globally, with well-known negative impacts on the marine environment. Despite the known negative short-term (minutes to hours) impact of shipping on individual animal behavioural responses, very little is understood about the long-term (months to years) impact on marine species presence and area use. This study took advantage of a planned rerouting of a major shipping lane leading into the Baltic Sea, to investigate the impact on the presence and foraging behaviour of a marine species known to be sensitive to underwater noise, the harbour porpoise (Phocoena phocoena). Passive acoustic monitoring data were collected from 15 stations over two years. Against predictions, no clear change occurred in monthly presence or foraging behaviour of the porpoises, despite the observed changes in noise and vessel traffic. However, long-term heightened noise levels may still impact communication, echolocation, or stress levels of individuals, and needs further investigation.

6.
Ecol Evol ; 14(3): e11169, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38529023

RESUMO

Hyadesimyia clausa Bigot is a morphologically striking tachinid that inhabits the Sub-Antarctic Ecoregion of the Magallanes Region in Chile and Tierra del Fuego province in Argentina. Much of the distributional information about this species is restricted to the Cape Horn islands, which have extreme environmental conditions, but the species' natural history, range limits, and habitat use have never been described or confirmed. Our goals were to describe the distributional limits of this sub-Antarctic fly with the help of citizen science and use this information type to describe this tachinid's habitat use and potential biological interactions with nonvascular and vascular flora. We found that citizen science significantly increased our understanding of the extent of occurrence, expanding the known distributional range by 195 km to the north and 153 km to the west. On the contrary, the values for the area of occupancy were not significant, but the occupancy overlap between different records was very low. We confirmed that H. clausa's habitat uses peatlands and although we have not provided evidence of pollination or movement of spores, we hypothesized, that the walking activity of H. clausa could help move sperm from mosses and pollen from the flowers of vascular plants, so they could act as potential pollinators. Citizen science can reduce and eliminate some scientific knowledge shortfalls and propose new ecological questions that could increase our knowledge of extreme ecosystems.

7.
Environ Res ; 251(Pt 2): 118621, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38492834

RESUMO

Pollution and bycatch are two of the main threats for cetaceans worldwide. These threats are exacerbated for nearshore species particularly for those in regions with intense industrial and fishing activities. Burmeister's porpoise is endemic to South America, has a Near Threatened conservation status because of long-term mortality in fisheries. Burmeister's porpoise occur in Mejillones Bay, northern Chile, a hot spot for heavy metals pollution from the mining industry and an intense industrial and artisanal purse-seine fishing area. From 2018 to 2021, we conducted systematic marine surveys to assess the abundance, distribution and habitat use of Burmeister's porpoises. We responded to stranding reports from 2018 to 2022, and necropsied nine individuals. From five of these, we analyzed the metal concentrations (As, Cd, Cr, Cu, Pb, Hg, Se and Zn) in muscle and skin tissues. Results showed an abundance of 76.17 individuals (CV = 25.9%) and an average density of 0.45 individuals/km2 (CV = 26%). Burmeister's porpoises were observed year round, 22.2% were mother-calf pairs present in austral summer at an average of 90.6 m depth in the southwestern bound of the bay. Two-thirds of stranded specimens died due to bycatch and one died due to bottlenose dolphin (Tursiops truncatus) attack. We report a dead Burmeister's porpoise positive for avian flu virus A (H5N1). Metals analyzed were found in muscle and skin tissues of stranded Burmeister's porpoises in the following order (Zn > Cu > Cr > As > Hg > Pb > Cd). Although we could not assess pollution as a cause of mortality, Cr, As and Pb concentrations exceeded the concentrations found in other porpoises species worldwide. We conclude that bycatch and pollution as the main threats for Burmeister's porpoise survival in northern Chile. Future studies should investigate the use of acoustic deterrent alarms to mitigate the bycatch in the bay and consider the Burmeister's porpoise as a sentinel species of pollution in northern Chilean coast.

8.
Ecology ; : e4296, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38527496

RESUMO

Competition is a prominent mechanism driving population dynamics and structuring community assemblage, which can be investigated by linking shifts in species' ecological niche and the densities of sympatric species because the ecological release from competitive constraints is a density-dependent process. In this work we determine how a steppe passerine community segregates their ecological niches and evaluate the role of competition in inducing changes in the ecological niche of species. We built multidimensional ecological niches (with Gaussian kernel density estimators) using data on the habitat features used by 10 bird species collected from seven sites in the natural steppes of Central Spain over 2 consecutive years. We computed distance and niche similarity metrics to explore the ecological niche partitioning of the bird community. Next, we ran multivariate linear regression models to evaluate the effects of conspecific and heterospecific density (as proxies of intraspecific and interspecific competition, respectively) on niche breadth and/or position of the three most abundant species. We found low niche overlap in the community assemblage but varying levels of niche similarity among pairs of species, which could increase the likelihood of current competition operating in the community. However, we found no effect of heterospecific density on niche breadth or position, although conspecific density was negatively related to niche breadth. Contrary to predictions of competition theory, increased density of conspecifics caused niche contraction. Our results from a multispecies system contribute to advanced knowledge of the biotic mechanisms structuring wildlife communities within the framework of ecological niche theory.

9.
Ecol Evol ; 14(2): e10938, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38333097

RESUMO

Studies of habitat use in breeding birds often assume species have relatively stable breeding distributions. Some species, however, display considerable year-to-year variability, complicating efforts to determine suitable or preferred habitats. After returning to their breeding range, Black-billed Cuckoos (Coccyzus erythropthalmus) and Yellow-billed Cuckoos (C. americanus) are thought to range widely before nesting, resulting in high rates of interannual breeding-site turnover, potentially contributing to conflicting habitat associations found in past studies. However, difficulty detecting these rare and declining species could lead to overinflated estimates of interannual turnover. Using broadcast surveys to increase detection probability, we collected detection/non-detection data in 2019 and 2020 at 41 publicly owned sites in Illinois and performed a dynamic, multi-scale occupancy analysis for each species to separate detection probability from potential interannual turnover and determine landscape and small-scale variables driving habitat use and occupancy dynamics. We found strong support for interannual turnover for both species based on poor performance of non-dynamic models and variation in estimated annual occupancy (20% and 21% increase between years for Black-billed and Yellow-billed Cuckoos, respectively). Black-billed Cuckoos persisted at sites with less forest in the surrounding landscape and used areas with denser understory vegetation. Yellow-billed Cuckoos colonized sites with greater canopy cover, avoided developed landscapes, and used areas with a shorter subcanopy layer. The dynamic nature of habitat use in these two cuckoo species suggests the importance of coordinating management and conservation across a broader spatial scale. Managing for larger patches of dense shrubs in less forested landscapes would benefit Black-billed Cuckoos while Yellow-billed cuckoos would benefit from management creating forested areas with open understories in less-developed landscapes.

10.
J Fish Biol ; 2024 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-38402691

RESUMO

Areas of importance to Southern Ocean skates are poorly defined. Here, we identify a deepwater skate egg case nursery in a discrete location at ~460 m depth off Cape Adare in the Southern Ocean. This is the first confirmed observation of a skate nursery area in the Ross Sea and only the second observation for the Southern Ocean. The morphology and size of the egg cases were consistent with the genus Bathyraja and most likely belong to the Bathyraja sp. (cf. eatonii). The nursery occurs within the "no take" General Protection Zone of the Ross Sea region marine protected area, where commercial fishing is prohibited.

11.
Mov Ecol ; 12(1): 10, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38297368

RESUMO

BACKGROUND: Measuring coastal-pelagic prey fields at scales relevant to the movements of marine predators is challenging due to the dynamic and ephemeral nature of these environments. Whale sharks (Rhincodon typus) are thought to aggregate in nearshore tropical waters due to seasonally enhanced foraging opportunities. This implies that the three-dimensional movements of these animals may be associated with bio-physical properties that enhance prey availability. To date, few studies have tested this hypothesis. METHODS: Here, we conducted ship-based acoustic surveys, net tows and water column profiling (salinity, temperature, chlorophyll fluorescence) to determine the volumetric density, distribution and community composition of mesozooplankton (predominantly euphausiids and copepods) and oceanographic properties of the water column in the vicinity of whale sharks that were tracked simultaneously using satellite-linked tags at Ningaloo Reef, Western Australia. Generalised linear mixed effect models were used to explore relationships between the 3-dimensional movement behaviours of tracked sharks and surrounding prey fields at a spatial scale of ~ 1 km. RESULTS: We identified prey density as a significant driver of horizontal space use, with sharks occupying areas along the reef edge where densities were highest. These areas were characterised by complex bathymetry such as reef gutters and pinnacles. Temperature and salinity profiles revealed a well-mixed water column above the height of the bathymetry (top 40 m of the water column). Regions of stronger stratification were associated with reef gutters and pinnacles that concentrated prey near the seabed, and entrained productivity at local scales (~ 1 km). We found no quantitative relationship between the depth use of sharks and vertical distributions of horizontally averaged prey density. Whale sharks repeatedly dove to depths where spatially averaged prey concentration was highest but did not extend the time spent at these depth layers. CONCLUSIONS: Our work reveals previously unrecognized complexity in interactions between whale sharks and their zooplankton prey.

12.
Sci Total Environ ; 914: 169946, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38199372

RESUMO

Waterbirds are vectors for the dissemination of antimicrobial resistance across environments, with some species increasingly reliant on highly anthropized habitats for feeding. However, data on the impact of their feeding habits on the carriage of antibiotic resistance genes (ARGs) are still scarce. To fill this gap, we examined the microbiota (16S rRNA amplicon gene sequencing) and the prevalence of ARG (high-throughput qPCR of 47 genes) in faeces from white storks (Ciconia ciconia) and lesser black-backed gulls (Larus fuscus) feeding in highly (landfill) and less (paddy fields) polluted habitats. Faecal bacterial richness and diversity were higher in gulls feeding upon landfills and showed a greater abundance of potential pathogens, such as Staphylococcus. In contrast, faecal bacterial communities from storks were similar regardless of habitat preferences, maybe due to a less intense habitat use compared to gulls. In addition, birds feeding in the landfill carried a higher burden of ARGs compared to the surrounding soil and surface waters. Network analysis revealed strong correlations between ARGs and potential pathogens, particularly between tetM (resistance to tetracyclines), blaCMY (beta-lactam resistance), sul1 (sulfonamide resistance) and members of the genera Streptococcus, Peptostreptococcus, and Peptoclostridium. Our work demonstrates how transitioning from paddy fields to landfills fosters the carriage of ARGs and potential pathogens in the bird gut, shedding light on the ecological role of these avian vectors in antimicrobial resistance dissemination.


Assuntos
Charadriiformes , Microbiota , Animais , Charadriiformes/genética , RNA Ribossômico 16S/genética , Aves , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/genética , Bactérias/genética , Genes Bacterianos , Instalações de Eliminação de Resíduos
13.
R Soc Open Sci ; 11(1): 230279, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38269074

RESUMO

Humpback whale song chorusing dominates the marine soundscape in Hawai'i during winter months, yet little is known about spatio-temporal habitat use patterns of singers. We analysed passive acoustic monitoring data from five sites off Maui and found that ambient noise levels associated with song chorusing decreased during daytime hours nearshore but increased offshore. To resolve whether these changes reflect a diel offshore-onshore movement or a temporal difference in singing activity, data from 71 concurrently conducted land-based theodolite surveys were analysed. Non-calf pods (n = 3082), presumably including the majority of singers, were found further offshore with increasing time of the day. Separately, we acoustically localized 217 nearshore singers using vector-sensors. During the day, distances to shore and minimum distances among singers increased, and singers switched more between being stationary and singing while travelling. Together, these findings suggest that the observed diel trends in humpback whale chorusing off Maui represent a pattern of active onshore-offshore movement of singers. We hypothesize that this may result from singers attempting to reduce intraspecific acoustic masking when densities are high nearshore and avoidance of a loud, non-humpback, biological evening chorus offshore, creating a dynamic of movement of singers aimed at increasing the efficiency of their acoustic display.

14.
Ecol Evol ; 14(1): e10867, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38274862

RESUMO

Global declines in tree populations have led to dramatic shifts in forest ecosystem composition, biodiversity, and functioning. These changes have consequences for both forest plant and wildlife communities, particularly when declining species are involved in coevolved mutualisms. Whitebark pine (Pinus albicaulis) is a declining keystone species in western North American high-elevation ecosystems and an obligate mutualist of Clark's nutcracker (Nucifraga columbiana), an avian seed predator and disperser. By leveraging traditional point count surveys and passive acoustic monitoring, we investigated how stand characteristics of whitebark pine in a protected area (Glacier National Park, Montana, USA) influenced occupancy and vocal activity patterns in Clark's nutcracker. Using Bayesian spatial occupancy models and generalized linear mixed models, we found that habitat use of Clark's nutcracker was primarily supported by greater cone density and increasing diameter of live whitebark pine. Additionally, we demonstrated the value of performing parallel analyses with traditional point count surveys and passive acoustic monitoring to provide multiple lines of evidence for relationships between Clark's nutcracker and whitebark pine forest characteristics. Our findings allow managers to gauge the whitebark pine conditions important for retaining high nutcracker visitation and prioritize management efforts in whitebark pine ecosystems with low nutcracker visitation.

15.
Ecol Appl ; 34(2): e2919, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37688799

RESUMO

The practice of space-for-time substitution assumes that the responses of species or communities to land-use change over space represents how they will respond to that same change over time. Space-for-time substitution is commonly used in both ecology and conservation, but whether the assumption produces reliable insights remains inconclusive. Here, we tested space-for-time substitution using data from the North American Breeding Bird Survey (BBS) and Global Forest Change (GFC) to compare the effects of landscape-scale forest cover on bird richness and abundance over time and space, for 25 space-time comparisons. Each comparison consisted of a landscape that experienced at least 20% forest loss over 19 years (temporal site) and a set of 15-19 landscapes (spatial sites) that represented the same forest cover gradient over space in 2019 as experienced over time in their corresponding temporal site. Across the 25 comparisons, the observed responses of forest and open-habitat birds to forest cover over time generally aligned with their responses to forest cover over space, but with comparatively higher variability in the magnitude and direction of effect across the 25 temporal slopes than across the 25 spatial slopes. On average, the mean differences between the spatial and temporal slopes across the 25 space-time comparisons frequently overlapped with zero, suggesting that the spatial slopes are generally informative of the temporal slopes. However, we observed high variability around these mean differences, indicating that a single spatial slope is not strongly predictive of its corresponding temporal slope. We suggest that our results may be explained by annual variability in other relevant environmental factors that combine to produce complex effects on population abundances over time that are not easily captured by snapshots in space. While not being a 1:1 proxy, measuring bird responses to changes in habitat amount in space provides an idea on how birds might be expected to eventually equilibrate to similar changes in habitat amount over time. Further, analyses such as this could be potentially used to screen for cases of regional space-time mismatches where population-limiting factors other than habitat could be playing a more important role in the population trends observed there.


Assuntos
Aves , Florestas , Animais , Fatores de Tempo , Ecologia
16.
Ecol Evol ; 13(12): e10765, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38077515

RESUMO

Animal dietary choices help us understand a species' feeding behaviour and are particularly relevant in conservation management. The aim of this study was to gather knowledge on dietary choices and the foraging behaviour of the Grizzled Giant Squirrel (Ratufa macroura) in Chinnar Wildlife Sanctuary, Southern Western Ghats, Kerala, India. The objectives were in particular to determine the food composition, seasonal fluctuations in food selection and feeding technique. Through an observational sampling method, focal animal sampling, the Grizzled Giant Squirrel in Chinnar Wildlife Sanctuary was found to feed on 30 plant species belonging to 18 families. The most used plant family was Fabaceae, with eight species, followed by Moraceae (four species) and Anacardiaceae (two species). The food species consumed included 22 trees, four climbers, one liana, one paraphyte, one shrub and one succulent species. The squirrel spent the most time feeding on Bauhinia racemosa (19.79%), followed by Tamarindus indica (14.08%) and Nothopegia beddomei (9.89%). The squirrel's diet choice was primarily influenced by the availability of food tree species and food resources rather than the season and nontree species were also found in the diet of Grizzled Giant Squirrel. Although the Grizzled Giant Squirrel exhibits some plasticity in its dietary choices, the available diversity of mature trees and plants as food sources appears to be important for its conservation in the fragmented riparian forest of the Western Ghats in Southern India.

17.
Animals (Basel) ; 13(24)2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-38136812

RESUMO

Small undisturbed patches in urban environments serve as important refuges for wildlife, e.g., hedgehogs. However, the effects of urbanization on certain biological aspects, like nesting behavior, remain unknown. We captured and tracked the movement of 30 male hedgehogs of two co-existing species: Algerian and European hedgehogs. The study was carried out in Valencia (eastern Spain). We distinguished six macrohabitats and five subhabitats. We analyzed the proportions of the macro and subhabitats where nests were found to calculate a resource selection function and fit GLMs. Hedgehog nests tended to concentrate in areas with little human disturbance and were built in hedges or under bush-like vegetation. We did not find any significant differences between species or other considered groups. We noted that nests were distributed around hard-to-find suitable habitat patches. We even recorded a case of two males from both species simultaneously using one nest. Our results suggest that hedgehog conservation in urban environments can be improved by the correct management of forest patches by conserving bush-like vegetation and improving the connectivity between suitable patches with ecological corridors.

18.
Proc Biol Sci ; 290(2010): 20230957, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37909073

RESUMO

Recent studies have suggested the presence of moonlight mediated behaviour in avian aerial insectivores, such as swifts. Here, we use the combined analysis of state-of-the-art activity logger data across three swift species, the common, pallid and alpine swifts, to quantify flight height and activity in responses to moonlight-driven crepuscular and nocturnal light conditions. Our results show a significant response in flight heights to moonlight illuminance for common and pallid swifts, i.e. when moon illuminance increased flight height also increased, while a moonlight-driven response is absent in alpine swifts. We show a weak relationship between night-time illuminance-driven responses and twilight ascending behaviour, suggesting a decoupling of both crepuscular and night-time behaviour. We suggest that swifts optimize their flight behaviour to adapt to favourable night-time light conditions, driven by light-responsive and size-dependent vertical insect stratification and weather conditions.


Assuntos
Aves , Voo Animal , Animais , Voo Animal/fisiologia , Aves/fisiologia , Insetos
19.
Animals (Basel) ; 13(21)2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37958070

RESUMO

This study presents the first successful capture using GPS tagging of a jaguar (Panthera onca) using a minimally invasive capture system (MICS). We used snare-foot traps and a MICS during two capture campaigns in a fragment of Atlantic Forest in southeastern Brazil. The specimen disarmed snares on different occasions, and capture was only possible with the MICS. The captured jaguar, an estimated 16-year-old adult male, was monitored using a GPS Vertex Plus Iridium collar with an optimal performance of 86% in expected locations. The jaguar's home range (659 km2 by MPC and 174 km2 by 95%K) was within the observed range for the species and the animal was primarily maintained in protected areas. The habitat types most frequently used were native grassland (27.2% of 4798 fixes), marsh (24.8%), and dense lowland forest (24.7%). The use of a MICS for trapping jaguars is a promising technique that shows advantages in terms of efficiency, selectivity, portability, reduced potential risk of injury to animals or trappers, and animal stress compared to other capture methods used for the species.

20.
Ecol Evol ; 13(10): e10624, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37869432

RESUMO

Agricultural commodity production is one the main drivers of deforestation in Legal Brazilian Amazonia resulting in a deforested and/or fragmented landscape formed by forest remnants of different sizes and shape embedded within the agricultural matrix. As an ecosystem engineer and a crucial seed predator, white-lipped peccaries (Tayassu pecari) play a pivotal role in forest structure, biodiversity, and nutrient cycling. However, they are highly sensitive to habitat fragmentation and hunting pressure. White-lipped peccaries are, therefore, a wide-ranging "landscape species," the spatial and ecological requirements of which can be used to guide conservation planning in human-modified landscapes. Using data from GPS-tracked individuals in large-scale mechanized agriculture landscapes in the state of Mato Grosso, Brazil's largest soybean and maize producer, we investiated the home range size and resource selection during both the crop and non-crop season. We observed a seasonal variation in home range size and an increased selection for croplands during the crop season. White-lipped peccaries favored native vegetation patches and also exhibited avoidance of locations distant from perennial water bodies and distant cropland locations far from forest remmants. This study can contribute to inform effective conservation strategies and land management practices aimed at preserving suitable habitats and promoting wildlife coexistence with working agricultural landscapes.

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