Population Viability Research Articles

Weirs: An effective tool to reduce hatchery–wild interactions on the spawning grounds?

AbstractObjectiveHatchery‐produced salmon and steelhead Oncorhynchus mykiss mitigate for habitat loss and support valuable commercial, recreational, and tribal fisheries. However, excessive interactions between hatchery and wild fish can also cause harm to wild populations. Weirs have been implemented as a management tool to remove returning hatchery‐origin Chinook Salmon O. tshawytcha adults to reduce the proportion of hatchery‐origin spawners (pHOS) in spawning areas used by their wild counterparts. Using a decade of data since new weirs were implemented, our objective was to evaluate the efficacy of this management approach.MethodsWeirs were installed in six tributaries of the lower Columbia River, Washington. Using data from both weir operations and spawning ground surveys, we quantified weir efficiency (the proportion of upstream migrants captured by the weir) and resultant pHOS in wild spawning areas and evaluated evidence for unintended effects of weirs on naturally spawning salmon in years with (2011–2017) and without weirs (2002–2010) in one population by evaluating weir effects on spawner apparent residence time, distribution, and recruitment to the juvenile stage.ResultWeir efficiencies were highly variable across years and locations (7.3–100.0%). Estimates of pHOS were variable among populations and years (interannual population mean range: 11.9% to 75.2%) but were higher in all but 2 of the 43 population‐year combinations than needed to maintain recovery‐plan‐targeted levels of population viability using quantitative genetic model‐based standards identified by the Hatchery Scientific Review Group. Several factors contributed to the proportion of hatchery spawners exceeding pHOS standards at the population level, including fish passing weirs during freshets, spawning below weir sites and in tributaries without weirs, and imperfect marking of hatchery‐released juveniles. In the sole watershed with sufficient pre‐weir data to evaluate before–after changes, we documented a downstream shift in the spatial distribution of redds, lower apparent residence time of spawners, and lower production of parr in years following weir installation.ConclusionOur results indicate that using weirs as a tool to reduce hatchery–wild interactions on the spawning grounds is challenging. Weir implementation reduced pHOS; however, in most cases, resulting pHOS was not low enough to facilitate fit and viable wild populations. Weirs also were associated with unintended negative impacts to the single population where we had adequate before and after weir implementation data to evaluate effects. These impacts may be harmful to recovery efforts and offset the intended benefits of weirs to wild populations. Our study highlights the need for adaptive management to realize the goals intended for weirs, underscores the need for experimental design approaches, and identifies opportunities for future work.

Optimizing the Antimicrobial Activity of Sodium Hypochlorite (NaClO) over Exposure Time for the Control of Salmonella spp. In Vitro.

Fish is a nutritionally rich product; however, it is easily contaminated by pathogenic microorganisms, such as Salmonella spp. Therefore, this study aimed to identify the best concentration of sodium hypochlorite (NaClO), exposure time, and water temperature that allow the most effective antimicrobial effect on the viable population of Salmonella spp. Thus, Salmonella Enteritidis ATCC 13076 and Salmonella Schwarzengrund were exposed to different time frames, ranging from 5 min to 38.5 min, temperatures between 5 and 38.5 °C, and NaClO concentrations ranging from 0.36 to 6.36 ppm, through a central composite rotational design experiment (CCRD). The results demonstrated that the ATCC strain exhibited a quadratic response to sodium hypochlorite when combined with exposure time, indicating that initial contact would already be sufficient for the compound's action to inhibit the growth of the mentioned bacteria. However, for S. Schwarzengrund (isolated directly from fish cultivated in aquaculture), both NaClO concentration and exposure time significantly influenced inactivation, following a linear pattern. This suggests that increasing the exposure time of NaClO could be an alternative to enhance Salmonella elimination rates in fish slaughterhouses. Thus, the analysis indicates that the Salmonella spp. strains used in in vitro experiments were sensitive to concentrations equal to or greater than the recommended ones, requiring a longer exposure time combined with the recommended NaClO concentration in the case of isolates from aquaculture.

Demographic response of osprey within the lower Chesapeake Bay to fluctuations in menhaden stock

Forage fish support the largest fisheries in the world and play a vital role in marine food webs by transferring energy from plankton to consumers within higher trophic levels. Growing commercial demand for these species and concern for the impact of over harvest on predator populations has driven a paradigm shift in management objectives from maximizing economic return to the establishment of ecosystem-based limits on harvest rates. How well current harvest policy supports noncommercial species like piscivorous birds remains poorly understood. We investigated the relationship between osprey breeding performance within the lower Chesapeake Bay and a menhaden stock index during a period (1974-2021) when the menhaden index fluctuated over 35-fold. Reproductive rate (young/pair/year), brood provisioning (fish/10-h) and the proportion of menhaden in the diet all declined during the study period. Indicators of food stress including brood reduction and nest failure increased during the study period. The population transitioned from reproductive surplus (demographic source) to reproductive deficit (demographic sink). A significant relationship between reproductive rate and the menhaden index suggests that osprey population viability requires that the menhaden stock be restored to 1980s levels. Current ecological reference points based on the food requirements of predatory fish are unlikely to protect the osprey population. We suggest the establishment of menhaden or reproductive thresholds designed to allow osprey to meet demographic targets (1.15 young/pair/year).

Exploration of Jaboticaba (Plinia cauliflora.) Cultivation in Bengkulu: Conservation in an Optimized Environment

Jaboticaba (Plinia cauliflora) is a plant with numerous benefits. The destruction of its natural habitat and illegal logging in areas where Jaboticaba grows have led to concerns about population decline. Therefore, serious conservation efforts are necessary to protect this plant. This research aims to plant and conserve Jaboticaba in an optimal environment in Bengkulu. To maintain the viability of jaboticaba populations, it is essential to protect their natural habitat and implement conservation efforts. The methods used included seedling preparation, jaboticaba planting, and treatment and observation of soil conditions, air, light, and height gain. The results indicated that Jaboticaba can grow in areas with soil pH 5.5; 50% soil moisture, 28℃ air temperature, 69% air humidity, and 900 µmol/m²/s light intensity. The study employed an experimental approach to investigate the growth of Jaboticaba. The growth of Jaboticaba from 15 cm to 30 cm was promoted within the study period through continuous care, including watering and fertilization. The study results indicate that environmental factors play an important role in the growth of Jaboticaba. Therefore, protecting its natural habitat in Bengkulu, Indonesia is crucial for environmental sustainability and human health. Jaboticaba holds high ecological, economic, and health values. The study's findings regarding the cultivation, environmental requirements, and urgency of conservation are enlightening for safeguarding this species for future generations.

Interactions Between Silver Nanoparticles and Culture Medium Biomolecules with Dose and Time Dependencies.

The interaction between silver nanoparticles (AgNPs) and molecules producing coronas plays a key role in cytotoxicity mechanisms. Once adsorbed coronas determine the destiny of nanomaterials in vivo, their effective deployment in the biomedical field requires a comprehensive understanding of the dynamic interactions of biomolecules with nanoparticles. In this work, we characterized 40nm AgNPs in three different nutritional cell media at different molar concentrations and incubation times to study the binding mechanism of molecules on surface nanoparticles. In addition, their cytotoxic effects have been studied in three cell lineages used as tissue regeneration models: FN1, HUV-EC-C, RAW 264.7. According to the data, when biomolecules from DMEM medium were in contact with AgNPs, agglomeration and precipitation occurred. However, FBS medium proteins indicated the formation of coronas over the nanoparticles. Nonetheless, little adsorption of molecules around the nanoparticles was observed when compared to DMEM supplemented with 10% FBS. These findings indicate that when nanoparticles and bioproteins from supplemented media interact, inorganic salts from DMEM contribute to produce large bio-coronas, the size of which varies with the concentration and time. The static quenching mechanism was shown to be responsible for the fluorescence quenching of the bioprotein aggregates on the AgNPs surface. The calculated bioprotein-nanoparticle surface binding constants were on the order of 105M-1 at 37°C, with hydrophobic interactions driven by enthalpy and entropy playing a role, as confirmed by thermodynamic analysis. Cytotoxicity data showed a systematic degrowth in the viable cell population as the number of nanoparticles increased and the diameter of coronas decreased. Cytotoxic intervals associated with half decrease of cell population were established for AgNPs molar concentration of 75µM for 24h and 50µM for 48h. In summary, through the cytotoxicity mechanism of bio-coronas we are able to manipulate cells' expansion rates to promote specific processes, such inflammatory mechanisms, at different time instants.

Incorporating life history diversity in an integrated population model to inform viability analysis

Life history diversity can significantly affect population dynamics and effects of management actions. For instance, variation in individual responses to environmental variability can reduce extirpation risk to populations, as the portfolio effect dampens temporal variability in abundance. Moreover, differences in habitat use may cause individuals to respond differently to habitat management and climate variability. To explore the role of life history diversity in population trajectories, population models need to incorporate within-population variation. Integrated population modeling (IPM) is a population modeling approach that offers several advantages for sharing information and propagating uncertainty across datasets. In this study, we developed an IPM for an endangered population of Chinook salmon ( Oncorhynchus tshawytscha) in the Wenatchee River, Washington, USA, that accounts for diversity in juvenile life histories, spawning location, and return age. Our analysis revealed that diversity in the age of juvenile emigration from natal streams had a portfolio effect, resulting in a 20% reduction in year-to-year variability in adult abundance in population projections. Our population viability analysis suggests that management interventions may be necessary to meet recovery goals, and our model should be useful for simulating the outcomes of proposed actions.

STUDY OF THE EFFICIENCY AND COMPARATIVE ANALYSIS OF THE APPLICATION OF TECHNIQUES FOR EVALUATING THE QUALITY OF PHYTOPHAGES AND ENTOMOPHAGES AT DIFFERENT STAGES OF ONTOGENESIS

The concept of quality control of insect crops is proposed, which is based on a targeted approach based on the goal and objectives of the implementation of a certain breeding program and is divided into two main directions: control of phytophage production, control of entomophage production. Quality control methods are based on the general biological rule of dependence between the intensity of insect taxis and the overall viability of biomaterial. The effectiveness of methods for assessing the quality of phytophages (on the example of the mother cultures of the grain moth Sitotroga cerealella, the wax moth Galleria mellonella) and entomophages (laboratory and natural populations of P. bioculatus.) of the Center for Mother Cultures of Insects Engineering and Technological Institute “Biotekhnica” of the National Academy of Sciences (ETI “Biotekhnica”) at different stages of ontogenesis was investigated using the indicator the intensity of taxis. As a result of research conducted on the culture of phytophagous, grain moth, a significant difference with the control was established in the indicators of viability of eggs, larvae, pupae and adults: 25; 6; 33 and 11%, respectively. Studies conducted with another phytophagous representative – the wax firefly – also showed positive results (16; 17; 16; 11%, respectively). The obtained (as a result of preliminary quality control) and selection culture had significantly higher viability indicators at all stages of ontogenesis. It was established that the intensity of chemotaxis of larvae of the 1st age of entomophages directly correlates with the indicator of viability of the insect culture. When selecting the starting material for successful culture, it is possible to select by chemotaxis of the larvae after rebirth from the egg. Thus, viability when selecting for Colorado beetle eggs significantly (p<0.01) exceeds this indicator in other selection options – Colorado beetle larvae and wax firefly larvae: 82; 59; 73% respectively. When working with an artificial population of P. bioculatus, on wax moth larvae, the highest intensity of taxis was noted in the variant with wax moth larvae compared to Colorado beetle eggs and Colorado beetle larvae – 37; 34; 29% respectively. This indicates a shift in the number of the population in the direction of individuals that successfully feed on unnatural food. Their viability was significantly higher than the viability in other variants of the study with an artificial population – 78; 71; 68% respectively. The proposed method of selection of starting material for cultivation of P. bioculatus allows differentiation of individuals for further effective reproduction, and the use of such biomaterial in programs of biological protection of plants from pests. A comparative analysis of methods for assessing the quality of phytophagous and entomophagous cultures at different stages of ontogenesis was carried out using the indicator of the overall viability of insect populations. It is an integrated indicator that takes into account the viability of the population at all stages of its development. All tested objects of the study showed that control and improvement of culture quality by the proposed method lead to an increase in the viability of biomaterial by 18.71; 18.56 and 8.86%, respectively (egg, larva, pupa).

Condition-transfer maternal effects modulate inter-locus sexual conflict

Abstract Strong sexual selection frequently favors males that increase their reproductive success by harming females, with potentially negative consequences for natural populations. Understanding what factors modulate conflict between the sexes is hence critical to understand both the evolution of male and female phenotypes and the viability of populations in the wild. Here, we model the evolution of male harm while incorporating male-induced maternal effects on offspring quality. We show that because male harm can induce condition-transfer maternal effects that reduce the quality of a harming male’s own offspring, maternal effects can partially align male and female evolutionary interests and significantly curb the evolution of male harm. These effects are independent of relatedness, the scale of competition, mating system, and whether male harm comes before (i.e., harassment) and/or during/after (i.e., traumatic inseminations or toxic ejaculates) mating and are particularly salient when maternal effects influence offspring ability to inflict (sons) or resist (daughters) harm. Our results underscore the potential importance of considering maternal effects to unravel the evolution of sexual conflict.

Evaluation of the therapeutic potential of infrapatellar fat pad adipose-derived stem cells and their secretome for regenerating knee articular cartilage in a rat model of osteoarthritis.

Mesenchymal stem cell (MSC) therapy has ameliorative effects for treating knee osteoarthritis (KOA) disease. Moreover, there is a growing interest in using MSCs-derived secretome (Sec) containing trophic factors secreted by MSCs for KOA treatment. Recently, some studies have suggested that the combination of MSCs and Sec has the potential to treat the diseases. This study aimed to evaluate the ameliorative effects of combined administration of infrapatellar fat pad (IPFP)-derived MSCs, a type of adipose-derived stem cells (ASCs), for treating degenerated cartilage in a rat model of KOA. IPFP-ASCs were isolated from the IPFP of male rats. Sec was obtained from IPFP-ASCs in the fourth passage. Eight weeks after the induction of KOA by collagenase II, the rats were divided into 5 groups (n=5), including a control group with no treatment, and four experimental groups that received sodium hyaluronate (Hyalgan®, Hya), ASCs, Sec, and IPFP-ASCs+Sec, respectively by an infrapatellar injection. To perform the pathological and radiological evaluations, the animals were sacrificed 8 weeks later. Our findings indicated that combined administration of the IPFP-ASCs and Sec statistically (P<0.05) improved scores of medial tibial and femoral condyles and medial fabella osteophytes. Also, it statistically (P<0.05) enhances the cartilage surface, matrix, cell distribution and population viability, and subchondral bone indices. No statistical difference was observed between IPFP-ASCs+Sec and IPFP-ASCs. Administration of IPFP-ASCs+Sec has a therapeutic potential to treat KOA in rats. However, there is no difference in the combined administration of IPFP-ASCs and Sec with IPFP-ASCs alone.

First steps to study the demography of vascular epiphytes in cities.

Urban ecosystems could jeopardize the existence of vascular epiphytes (VE) given that their occurrence is linked to phorophyte availability and particular climatic conditions. Despite reports of VE in cities, nothing is known about their demography. A first step in this direction is to describe their population structures (PS). We established the PS of VE present in urban parks in Oaxaca City (Mexico), addressing the following questions: 1) what is their demographic status? and 2) are there differences in the structure of populations growing in native versus exotic phorophytes? During 2021, we censused all the trees in six urban parks, recording their origin (native or exotic), the epiphytic species found on them and the development stages present in each VE population. Overall, five VE species were documented: Tillandsia ionantha, T. makoyana, T. sp., T. schiedeana and T. recurvata (Bromeliaceae); the first three with only one individual and the latter two with 95 and 5,694, respectively. A MANOVA test indicated significant differences in PS between T. recurvata (type I structure, suggesting a growing population) and T. schiedeana (type III structure, suggesting a senile population) (Wilkes' λ= 0.821, F-Radio= 11.96 P<0.001). PS showed no differences related to tree origin. Our results indicate that it is necessary to conduct demographic studies to have a more accurate idea of the current condition of vascular epiphytes in cities. For instance, even though we found five VS species, only one of them seems to have viable populations in Oaxaca city.

Isolation of Primary Mouse Hepatocytes and Non-Parenchymal Cells from a Liver with Precancerous Lesions.

In the early stages of liver carcinogenesis, rare hepatocytes and cholangiocytes are transformed into preneoplastic cells, which can progressively acquire a neoplastic phenotype, favored by the failure of natural antitumor immunosurveillance. The detailed study of both hepatic parenchymal (e.g., hepatocytes) and non-parenchymal cells (NPCs), such as immune cells, could help understand the cellular microenvironment surrounding these pre-cancerous and neoplastic lesions.Cultures of primary hepatocytes are of interest in various biomedical research disciplines, serving as an ex vivo model for liver physiology. Obtaining high viability and yield of primary mouse hepatocytes and other liver cell populations is technically challenging, thus limiting their use. In the first section of the current chapter, we introduce a protocol based on the two-step collagenase perfusion technique (by inferior vena cava) to isolate hepatocytes and, to a lower extent, NPCs and detailed the different considerations to take into account for a successful perfusion. The liver is washed by perfusion, hepatocytes are dissociated with collagenase, and different cell populations are separated by centrifugation. Various techniques have been described for the isolation of healthy and malignant hepatocytes; however, the viability and purity of the isolated cells is frequently not satisfactory. Here, we significantly optimized this protocol to reach improved yield and viability of the hepatocytes and concomitantly obtain preserved NPC populations of the liver.Within NPCs, tissue-resident or recruited immune cells are essential actors regulating hepatocarcinogenesis. However, simultaneous isolation of hepatic leukocytes together with other cell types generally yields low immune cell numbers hindering downstream application with these cells. In the second section of this chapter, as opposed to the first section primarily aiming to isolate hepatocytes, we present a tissue dissociation protocol adapted to efficiently recover leukocytes from non-perfused bulk (pre-)cancerous livers. This protocol has been optimized to be operator-friendly and fast compared to other liver processing methods, allowing easy simultaneous sample processing to retrieve hepatic (tumor-infiltrating) immune cells.

Development of alternative diagnosis of HH1, HH3, HH5 and HCD fertility haplotypes and subfertility syndrome in cattle

AbstractThe increasing prevalence of hereditary anomalies in Holstein cattle populations presents a pressing issue, leading to concerns such as embryonic mortality and the birth of non‐viable offspring. This study addresses the urgency of managing harmful genetic mutations in Holstein cattle by developing alternative diagnostic methods. The research aims to devise effective means to diagnose fertility haplotypes HH1, HH3, HH5, HCD and BY and subfertility syndrome in cattle. To achieve this goal, a range of molecular genetic techniques were employed, including Tetra‐Primer ARMS‐PCR methods, PCR‐RFLP analysis and allele‐specific PCR. These methods facilitated the identification of heterozygous carriers of various fertility haplotypes and subfertility syndrome in Holstein cows and servicing bulls. The study reveals the prevalence of these genetic defects within the Republic of Kazakhstan's cattle population. HH1, HH3, HH5, HCD and BY fertility haplotypes were found to have occurrence rates ranging from 1.4% to 16.6%, with subfertility syndrome detected in 4.5% of Simmental bulls. The practical significance of this research lies in its contribution to genetic monitoring and management strategies for Holstein cattle populations. By introducing affordable, rapid and accurate diagnostic methods, such as the T‐ARMS‐PCR, the study provides a valuable tool for controlling and mitigating the spread of harmful genetic mutations, ultimately improving the overall genetic health and productivity of Holstein cattle in the region. This research addresses a critical need in the cattle breeding industry and underscores the importance of genetic monitoring to ensure the long‐term viability and sustainability of Holstein cattle populations.

Northward migration of Red Knots Calidris canutus rufa and environment connectivity of southern Brazil to Canada

Summary During their northward migration, Red Knots Calidris canutus rufa stop at the Lagoa do Peixe National Park in the extreme south of Brazil to build up fat reserves for their journey to their Canadian breeding grounds. We tracked five Red Knots with PinPoint Argos-75 GPS transmitters to investigate differences in migration strategies from this stopover. Tracked birds used two different routes: the Central Brazil route and the Brazilian Atlantic Coast route. One bird flew 8,300 km straight from Lagoa do Peixe to the Delaware Bay (USA). Another bird stopped in Maranhão (north-east Brazil) and a third one used a yet unknown environment for the species, the mouth of the Amazon River at Baía Santa Rosa, Brazil. These two birds made short flights, covering stretches of 1,600 km to 3,600 km between stop-overs, where they stayed from 4 to 18 days. Our study highlights the occurrence of intrapopulation variation in migratory strategies and reveals the connectivity of environments that are essential for the viability of rufa Red Knot populations.

Microwave-enhanced antibacterial activity of polydopamine-silver hybrid nanoparticles.

The ever-increasing risks posed by antibiotic-resistant bacteria have stimulated considerable interest in the development of novel antimicrobial strategies, including the use of nanomaterials that can be activated on demand and result in irreversible damage to pathogens. Microwave electric field-assisted bactericidal effects on representative Gram-negative and Gram-positive bacterial strains were achieved in the presence of hybrid polydopamine-silver nanoparticles (PDA-Ag NPs) under low-power microwave irradiation using a resonant cavity (1.3 W, 2.45 GHz). A 3-log reduction in the viability of bacterial populations was observed within 30 minutes which was attributed to the attachment of PDA-Ag NPs and associated membrane disruption in conjunction with the production of intra-bacterial reactive oxygen species (ROS). A synergistic effect between PDA and Ag has been demonstrated whereby PDA acts both as an Ag NP carrier and a microwave enhancer. These properties together with the remarkable adhesivity of PDA are opening a route to design of antibacterial adhesives and surface coatings for prevention of biofilm formation.

Development of an improved colonization system for human-derived Bifidobacterium longum subsp. longum in conventional mice through the feeding of raffinose or 1-kestose.

How bifidobacteria colonize and survive in the intestine is not fully understood. The administration of bifidobacteria to conventional mice can be used to evaluate their ability to colonize the intestine in the presence of endogenous gut microbiota. However, human-derived bifidobacteria do not readily colonize the intestines of conventional mice, and although colonization by Bifidobacterium breve UCC2003 has been achieved, the viability of such populations requires improvement. Therefore, we aimed to establish a colonization system with human-derived bifidobacteria of high viability in conventional mice using Bifidobacterium longum subsp. longum 105-A. Lactose, raffinose, and 1-kestose were identified as the preferred carbohydrate sources for the growth of this strain in culture. The administration of B. longum 105-A to conventional BALB/c mice fed these carbohydrates showed that diets containing 6% (w/w) raffinose or 1-kestose facilitated colonization with >108 colony-forming units/g feces for 2 weeks. The population of this strain was more stable in the raffinose-fed group than in the 1-kestose-fed group. The ingestion of these prebiotics had a greater impact on the composition of the microbiota than the administration of B. longum 105-A. The ingestion of these prebiotics also increased the fecal concentrations of organic acids, which was indicative of greater intestinal fermentation. Collectively, we established a colonization system for B. longum 105-A with high viability in conventional mice by feeding the mice raffinose or 1-kestose. This system should be useful for elucidation of the mechanisms of colonization and survival of bifidobacteria in the intestines in the presence of the endogenous gut microbiota.

Population, nesting characteristics, and breeding ecology of the critically endangered Gyps indicus in Mudumalai Tiger Reserve, South India

The species extinction rate has recently accelerated worldwide and is a thousand times higher than through natural processes alone. Small, isolated populations are especially vulnerable to extinction due to deterministic and stochastic threats. Hence, the conservation of such populations is challenging. The present study from 2015 to 2021 aimed to understand the population, nesting characteristics, and breeding ecology of the country’s southernmost population of Gyps indicus in Mudumalai Tiger Reserve, South India. The population estimation was performed on the roosting and nesting sites of Gyps indicus in the Mudumalai Tiger Reserve. To study the nesting characteristics and breeding ecology, each nesting colony was systematically visited four times per month during the breeding season (October to May). Assessments of threats were estimated during the field visits. In 2015–2021, four breeding sites were identified. Two nesting sites were identified in 2016 and two more in 2017 and 2020. The mean altitude of the nesting sites was 1122.25 ± 170.06 m a.s.l., ranging from 821 m a.s.l. to 1600 m a.s.l. In the Protected Area, two nests were located on east-facing exposure, one nest on southeast-facing exposure, and one nest on south-facing exposure. In terms of population composition, the mean number of adult individuals steadily increased from 9.5 ± 0.46 in 2016 to 14.08 ± 0.67 in 2021. Consequently, the mean total number of individuals per colony increased from 13.66 ± 0.56 in 2016 to 27.83 ± 0.62 in 2021. A total of 40 (in average, 6.66 ± 0.49 pairs/year) territorial pairs with occupied nests were observed in 2015–2021. Of them, 31 (in average, 5.16 ± 0.30 pairs/year) breeding pairs had laid eggs. Successful incubation was recorded, and the mean incubation period was 63.64 ± 1.74 days. Out of 31 incubated nests, 23 fledglings (3.83 ± 0.47 individuals/year) successfully came out with 74% breeding success. The entire nesting period was 128.43 ± 1.16 days. In total, out of 17 failed breeding attempts nine (53%) were detected before egg laying, and eight (47%) were found during incubation. There were no significant differences between nests abandoned before and after egg laying (t = 0.4152, p &gt; 0.05). During the breeding seasons of 2015–2017, a human-made forest fire posed a serious threat to nesting colonies of Gyps indicus, resulting in no observed nesting. A species-specific conservation-oriented action programme is necessary to secure this last southernmost wild viable Gyps indicus population in the Mudumalai Tiger Reserve. At this juncture, we highly recommend declaring the buffer zone of the Mudumalai Tiger Reserve as a «Vulture Sanctuary» to provide a legal protection of the Gyps indicus population living in the studied area.

Host and floral communities shape parasite prevalence and reproduction in intensively managed forests

AbstractUnderstanding how working landscapes can maintain viable wildlife populations is key to evaluating their conservation potential. We assessed the potential of intensively managed conifer forests for supporting healthy, productive bee populations in one of the major timber‐growing regions of the world, the Pacific Northwest. We examined the direct effect of the number of years post‐harvest and other forest characteristics on flowering plant and bee communities and their indirect effect on parasite prevalence (Apicystis spp., Ascosphaera spp., and Crithidia spp.) and reproduction of a native, forest‐dwelling solitary bee (Osmia lignaria). Forest characteristics, including the time elapsed since harvest, influenced floral and bee community diversity and abundance and indirectly impacted parasite prevalence and offspring production. We found that increased bee diversity was associated with reduced parasite prevalence—consistent with a dilution effect—but the strength of the relationship varied across the different parasites. Additionally, bee abundance was more consistently associated with increased parasite prevalence, providing evidence of amplification. Floral abundance was only associated with lower Apicystis spp. prevalence. Across all parasite models, however, the values were &lt;20%, indicating that additional factors shape bee communities beyond those we examined. Offspring production was positively related to floral diversity but not to parasite prevalence. Our results suggest that managing floral diversity is critical to enhancing the value of these landscapes for wild bee communities, both directly through promoting bee diversity and reproduction, and indirectly through facilitating parasite dilution.

Environmental complexity mitigates the demographic impact of sexual selection.

Sexual selection and the evolution of costly mating strategies can negatively impact population viability and adaptive potential. While laboratory studies have documented outcomes stemming from these processes, recent observations suggest that the demographic impact of sexual selection is contingent on the environment and therefore may have been overestimated in simple laboratory settings. Here we find support for this claim. We exposed copies of beetle populations, previously evolved with or without sexual selection, to a 10-generation heatwave while maintaining half of them in a simple environment and the other half in a complex environment. Populations with an evolutionary history of sexual selection maintained larger sizes and more stable growth rates in complex (relative to simple) environments, an effect not seen in populations evolved without sexual selection. These results have implications for evolutionary forecasting and suggest that the negative demographic impact of sexually selected mating strategies might be low in natural populations.

Global and regional patterns in distribution and threat status of zoo collections of turtles and tortoises

Turtles are a globally threatened group of reptiles. Zoo populations may contribute to the conservation of species, including turtles, but collection composition may not align with conservation needs. We combined data from the Zoological Information Management System (ZIMS), EDGE of Existence, the IUCN Red List and the Reptile Database to investigate zoo turtle holdings on global and regional scales. Globally, zoo collections were representative of turtle diversity, regional species distributions and threat statuses, indicating no bias towards threatened species and no taxonomic or distribution blind spots. Species kept in zoos had significantly lower EDGE scores than those not represented, and threatened species were no more likely to have been bred in the year prior to data collection (before March 2022) or have non-viable populations, but were more likely to have a larger population size. Although Africa, Asia and South America have the smallest turtle holdings in terms of species, allowing for regional capacity, these regions hold more, while Europe holds fewer than expected turtle species – North American and Asian holdings do not differ from expected. African, Asian, North and South American regions significantly bias their collections towards native species. We found evidence for significant increases in turtle populations at the genus level following the EAZA Shellshock campaign in Europe. ZIMS data are limited by taxonomy, membership and accuracy of records but provide the best window into patterns of zoo turtle collections. While holding a species in a zoo does not equate to conservation value, based on these data, we recommend that conservation prioritisation exercises are developed for all turtle species, holding institutions or regional taxonomic advisory address population viability and support for institutions working with significant turtle populations in captivity to join ZIMS is provided. Keywords: chelonia, ex-situ, zoos, conservation, ZIMS

Functional responses in American marten habitat selection indicate cumulative effects of progressive habitat change

AbstractShifts in habitat selection may serve as behavioral indicators of changing habitat quality and can provide an insight into the effects of chronic disturbance on wildlife populations before rates of occurrence and other metrics related to population viability are affected. Long‐term studies can provide unique opportunities to understand animals' behavioral responses to the cumulative effects of habitat disturbance that may be missed by short‐term studies or space‐for‐time substitution. Using the American marten (Martes americana) as a focal species, we evaluated the effects of progressive habitat disturbance on an animal population by identifying changes in habitat availability and selection over time. Marten are strongly associated with mature forest conditions and are thus sensitive to forest harvesting, which is a chronic and prevalent form of disturbance across the species' range. We developed resource selection functions that characterized both temporally consistent patterns and functional responses in the relative selection of habitats by marten at the patch scale. We used a combination of marten location data collected during three periods over 30 years of extensive forest change in northern Maine and a habitat classification scheme informed by species' behavior and designed to capture habitat changes over time. Marten increased their selection of tall (&gt;12 m mean tree height) mature forest, including uncut forest and regenerated clearcuts, in response to decreased availability. Marten also increased avoidance of early‐successional forest (&lt;9 m mean tree height) in response to increased availability. These functional responses in habitat selection appear to enable marten to maintain access to required resources in mature forest and limit exposure to risky or resource‐poor habitat within home ranges. However, a declining trend in the occurrence of resident adult females may indicate a limit to the functional response strategies for individuals unable to incur the energetic or prey‐related costs that may be associated with strong functional responses. Our results suggest that, despite adaptive habitat selection strategies, there are minimum thresholds of mature forest availability below which resident adults, particularly females, will struggle to persist. We recommend forest management strategies targeted at minimizing the strength of functional responses displayed by marten within occupied landscapes.