Constant gardeners: Endozoochory promotes repeated seedling recruitment in clonal plants

[EN] Paradoxically, seedlings of clonal plants are rarely observed in nature, despite many of these species producing large amounts of seeds every fruiting season. Studies about clonal plants’ recruitment strategies are usually based on experiments carried out under controlled conditions (e.g., laboratory) and rarely consider frugivores’ effects. We tested the role of endozoochory in the seedling recruitment in natural conditions of the bilberry Vaccinium myrtillus, a widely distributed clonal species and a key resource in temperate and boreal regions of Eurasia, which has been suggested to recruit at occasional windows of opportunity (unpredictable conditions in which seedling recruitment may occur within conspecific adult stands). We marked brown bear Ursus arctos, mesocarnivore (red foxes Vulpes vulpes and martens Martes spp.) and passerine feces containing bilberry seeds in the Tatra Mountains (Carpathian Mountains, Southern Poland) and followed the fate of the embedded seeds during two years. We detected bilberry germination associated with 100%, 87.5%, and 50% of brown bear, mesocarnivore, and passerine feces, and also in 43.6%, 41.2%, and 23.1% of the control plots located 5, 10, and 30 m away from the bear scats, respectively. In bear scats, investigated in more detail, 15.7% of the seedlings survived at least one year. The largest numbers of seedlings were associated with bear scats (154.4 ± 237.3 seedlings/m2), especially to those defecated upon the soil disturbances these animals create next to their resting sites. Our results demonstrate that endozoochory facilitates repeated bilberry seedling recruitment in nature, suggesting that studies on the reproductive strategies of clonal plants must consider the role of frugivores. Some frugivores’ behaviors, such as the defecation by bears in the vicinity of their resting sites, may in fact be crucial for the reproduction of clonal plants and for the adaptation of these species to the current changing climatic conditionsSIThis study was supported by the BearConnect project funded by the National Science Centre in Poland (2016/22/Z/NZ8/00121) through the 2015–2016 BiodivERsA COFUND call for research proposals, with the national funders ANR/DLR-PT/UEFISCDI/NCN/ RCN. We thank Aida Parres, Danuta Frydryszak, Carlos Bautista, Katarzyna Chrzaz scik, and Max Murgio for their help during the fieldwork and Tomasz Zwijacz-Kozica for providing the GPS locations of brown bear clusters. Tatra National Park provided the necessary permits to conduct the field work. A stimulating discussion with Sam Steyaert and comments made by two anonymous reviewers improved the overall quality of this manuscript. AGR and NS conceived the study, designed the methodology, and conducted the fieldwork. AGR performed all statistical analyses and wrote a first draft of the manuscript with significant contributions of NS. The authors declare no conflict of interes

Resource pulses and human–wildlife conflicts

Pulsed resources have prominent effects on community and ecosystem dynamics; however, there is little research on how resource pulses affect human–wildlife interactions. Tree masting is a common type of pulsed resource that represents a crucial food for many species and has important bottom-up effects in food webs. In anthropogenic landscapes, years of food shortage after mast years can have negative outcomes for both people and wildlife, for instance when an increased use of anthropogenic foods by animals exacerbates human–wildlife conflicts. Here, we used novel remote sensing indicators of forest productivity and phenology, together with weather cues and ground measures of mast production, to assess whether years of masting and crop failures lead to changes in human–wildlife conflict occurrence. We used a unique 14-year dataset including the production of European beech Fagus sylvatica seeds and brown bear Ursus arctos damage in the northeastern Carpathians as our model system. Linking these data in a panel regression framework, we found that temporal fluctuations in damage occurrence were sensitive to the year-to-year variation in beechnut production. Specifically, the number of damages during bear hyperphagia (i.e., September to December, when bears need to accumulate fat reserves prior to hibernation) was significantly higher in years with low beechnut production than in normal or mast years. Furthermore, we provide evidence that beech masting and failure can be predicted through a combination of remote-sensing, weather, and field indicators of forest productivity and phenology. We demonstrate how pulsed resources, such as tree masting, can percolate through food webs to amplify human–wildlife conflict in human-dominated landscapes. Given the recent range expansion of large carnivores and herbivores in many regions, including Europe, predicting years of natural food shortage can provide a pathway to proactive damage prevention, and thus to foster coexistence between wildlife and people.Peer Reviewe

Seasonal species interactions minimize the impact of species turnover on the likelihood of community persistence

Many of the observed species interactions embedded in ecological communities are not permanent, but are characterized by temporal changes that are observed along with abiotic and biotic variations. While work has been done describing and quantifying these changes, little is known about their consequences for species coexistence. Here, we investigate the extent to which changes of species composition impacts the likelihood of persistence of the predator-prey community in the highly seasonal Bialowieza Primeval Forest (NE Poland), and the extent to which seasonal changes of species interactions (predator diet) modulate the expected impact. This likelihood is estimated extending recent developments on the study of structural stability in ecological communities. We find that the observed species turnover strongly varies the likelihood of community persistence between summer and winter. Importantly, we demonstrate that the observed seasonal interaction changes minimize the variation in the likelihood of persistence associated with species turnover across the year. We find that these community dynamics can be explained as the coupling of individual species to their environment by minimizing both the variation in persistence conditions and the interaction changes between seasons. Our results provide a homeostatic explanation for seasonal species interactions, and suggest that monitoring the association of interactions changes with the level of variation in community dynamics can provide a good indicator of the response of species to environmental pressures

The role of the brown bear Ursus arctos as a legitimate megafaunal seed disperser

© Te Author(s) 2021[EN] Megafaunal frugivores can consume large amounts of fruits whose seeds may be dispersed over long distances, thus, affecting plant regeneration processes and ecosystem functioning. We investigated the role of brown bears (Ursus arctos) as legitimate megafaunal seed dispersers. We assessed the quantity component of seed dispersal by brown bears across its entire distribution based on information about both the relative frequency of occurrence and species composition of fleshy fruits in the diet of brown bears extracted from the literature. We assessed the quality component of seed dispersal based on germination experiments for 11 fleshy-fruited plant species common in temperate and boreal regions and frequently eaten by brown bears. Across its distribution, fleshy fruits, on average, represented 24% of the bear food items and 26% of the total volume consumed. Brown bears consumed seeds from at least 101 fleshy-fruited plant species belonging to 24 families and 42 genera, of which Rubus (Rosaceae) and Vaccinium (Ericaceae) were most commonly eaten. Brown bears inhabiting Mediterranean forests relied the most on fleshy fruits and consumed the largest number of species per study area. Seeds ingested by bears germinated at higher percentages than those from whole fruits, and at similar percentages than manually depulped seeds. We conclude that brown bears are legitimate seed dispersers as they consume large quantities of seeds that remain viable after gut passage. The decline of these megafaunal frugivores may compromise seed dispersal services and plant regeneration processes.SITis study was supported by the BearConnect project funded by the National Science Centre in Poland, (2016/22/Z/NZ8/00121) through the 2015–2016 BiodivERsA COFUND call for research proposals, with the national funders ANR/DLR-PT/UEFISCDI/NCN/RCN. Additional funding from the Polish Ministry of Science and Higher Education (project NN304-294037, NS), the National Science Centre in Poland (project DEC-2013/08/M/NZ9/00469, NS), the National Centre for Research and Development (GLOBE, POLNOR/198352/85/2013, NS, JA) is also acknowledged. We thank the director and staf from the Warsaw Municipal Zoological Garden and from the Krakow Botanical Garden, for providing support and facilities to conduct the bear feeding trials and germination experiment. We thank Teresa Berezowska-Cnota for inspecting seed germination in 2010, and Katarzyna Bojarska for coordinating in the feld part of the seed counting in bear faeces. We appreciate the help from volunteers and students of the Carpathian Brown Bear Project in feld data collection in the Bieszczady Mountains. We thank Kim McConkey and one anonymous reviewer that provided constructive suggestions that greatly improved the manuscript

The role of the brown bear Ursus arctos as a legitimate megafaunal seed disperser

Megafaunal frugivores can consume large amounts of fruits whose seeds may be dispersed over long distances, thus, affecting plant regeneration processes and ecosystem functioning. We investigated the role of brown bears (Ursus arctos) as legitimate megafaunal seed dispersers. We assessed the quantity component of seed dispersal by brown bears across its entire distribution based on information about both the relative frequency of occurrence and species composition of fleshy fruits in the diet of brown bears extracted from the literature. We assessed the quality component of seed dispersal based on germination experiments for 11 fleshy-fruited plant species common in temperate and boreal regions and frequently eaten by brown bears. Across its distribution, fleshy fruits, on average, represented 24% of the bear food items and 26% of the total volume consumed. Brown bears consumed seeds from at least 101 fleshy-fruited plant species belonging to 24 families and 42 genera, of which Rubus (Rosaceae) and Vaccinium (Ericaceae) were most commonly eaten. Brown bears inhabiting Mediterranean forests relied the most on fleshy fruits and consumed the largest number of species per study area. Seeds ingested by bears germinated at higher percentages than those from whole fruits, and at similar percentages than manually depulped seeds. We conclude that brown bears are legitimate seed dispersers as they consume large quantities of seeds that remain viable after gut passage. The decline of these megafaunal frugivores may compromise seed dispersal services and plant regeneration processes.This study was supported by the BearConnect project funded by the National Science Centre in Poland, (2016/22/Z/NZ8/00121) through the 2015–2016 BiodivERsA COFUND call for research proposals, with the national funders ANR/DLR-PT/UEFISCDI/NCN/RCN. Additional funding from the Polish Ministry of Science and Higher Education (project NN304-294037, NS), the National Science Centre in Poland (project DEC-2013/08/M/NZ9/00469, NS), the National Centre for Research and Development (GLOBE, POL-NOR/198352/85/2013, NS, JA) is also acknowledged.Peer reviewe

Effectiveness of different types of hair traps for brown bear research and monitoring

Non-invasive sampling by hair-trapping is increasingly used worldwide in wildlife research. Despite this rise and the potential of hair samples for ecology and conservation studies, the relative performance of hair collection devices has been rarely tested. Here, we compare the effectiveness of five types of hair traps for brown bears Ursus arctos in the Carpathian Mountains (SE Poland) and test the effects of trap type, season, number of days elapsed since trap installation and trap features on the trapping success in order to provide recommendations for optimal sampling in future studies. The trap types were corral, path-trap, "smola"(beechwood tar) tree-trap, turpentine tree-trap and natural rub. In 2010, we collected 858 hair samples during 2330 inspections of 175 hair traps and found that the most effective traps were smola tree-traps (mean percentage of successful inspections ± SD: 30.2% ± 26.0) and natural rubs (50.8% ± 16.7). Based on this finding, over the following 2 years we focused on 24 smola tree-traps and eight natural rubs. During this long-term survey (2010-2012, 969 inspections, 1322 samples collected) the trapping success increased with time and smola tree-traps achieved similar effectiveness to natural rubs (45.5% ± 29.7 and 45.9 ± 23.4, respectively). We show that when baiting smola tree-traps ten weeks prior to research or monitoring, sampling effectiveness can reach up to 30%. Taking into account the logistical and methodological constraints associated with detecting and using natural rubs for a proper survey design, we recommend using smola tree-traps baited in advance for hair sampling in wildlife studies

Carrion Availability in Space and Time

Introduction Availability of carrion to scavengers is a central issue in carrion ecology and management, and is crucial for understanding the evolution of scavenging behaviour. Compared to live animals, their carcasses are relatively unpredictable in space and time in natural conditions, with a few exceptions (see below, especially Sect. “Carrion Exchange at the Terrestrial-Aquatic Interface”). Carrion is also an ephemeral food resource due to the action of a plethora of consumers, from microorganisms to large vertebrates, as well as to desiccation (i.e., loss of water content; DeVault et al. 2003; Beasley et al. 2012; Barton et al. 2013; Moleón et al. 2014). With a focus on vertebrate carcasses, here we give an overview of (a) the causes that produce carrion, (b) the rate of carrion production, (c) the factors affecting carrion quality, and (d) the distribution of carrion in space and time, both in terrestrial and aquatic environments (including their interface). In this chapter, we will focus on naturally produced carrion, whereas non-natural causes of animal mortality are described in chapter “Human-Mediated Carrion: Effects on Ecological Processes”. However, throughout this chapter we also refer to extensive livestock carrion, because in the absence of strong restrictions such as those imposed in the European Community after the bovine spongiform encephalopathy crisis (Donázar et al. 2009; Margalida et al. 2010), the spatiotemporal availability of carrion of extensive livestock and wild ungulates is similar

Correcting for enzyme immunoassay changes in long term monitoring studies

Enzyme immunoassays (EIAs) are a common tool for measuring steroid hormones in wildlife due to their low cost, commercial availability, and rapid results. Testing technologies improve continuously, sometimes requiring changes in protocols or crucial assay components. Antibody replacement between EIA kits can cause differences in EIA sensitivity, which can hinder monitoring hormone concentration over time. The antibody in a common cortisol EIA kit used for long-term monitoring of stress in wildlife was replaced in 2014, causing differences in cross reactivity and standard curve concentrations. Therefore, the objective of this study was to develop a method to standardize results following changes in EIA sensitivity. We validated this method using cortisol concentrations measured in the hair of brown bears (Ursus arctos). • We used a simple linear regression to model the relationship between cortisol concentrations using kit 1 and kit 2. • We found a linear relationship between the two kits (R2 = 0.85) and used the regression equation (kit2 = (0.98 × kit1) + 1.65) to predict cortisol concentrations in re-measured samples. • Mean predicted percent error was 16% and 72% of samples had a predicted percent error <20%, suggesting that this method is well-suited for correcting changes in EIA sensitivity.publishedVersio

The diet of the Marbled Teal Marmaronetta angustirostris in southern Alicante, eastern Spain

We present a study of the diet of the globally threatened Marbled Teal Marmaronetta angustirostris in the southern Alicante wetlands, the most important site for the European population. We analysed the gut contents of 64 fully-grown teal collected between 16 June and 24 November from 1992 to 2000, and 31 ducklings (29 of the newly hatched age class I a) collected between 18 May and 16 July from 1994 to 1998. The ducklings died following rescue from a concrete irrigation channel, and all but 4 fully-grown teal died in various mortalities. We also analysed 20 faecal samples collected from fully-grown teal in July-August in 1999 and 2000, plus faecal samples collected from five broods after their rescue from the channel. Seeds (72% by aggregate percent of gullet volume), supplemented by invertebrates (21%) dominated gut samples from fully-grown teal. The most important food item was Scirpus litoralis seeds (43% by aggregate percent of gullet volume) consumed mainly when floating on the water surface. The importance of invertebrates was probably underestimated owing to the poor quality of gut samples. Chironomid larvae and pupae, Corixidae and their eggs, ants, ostracods and amphipods were the most abundant invertebrates by volume. Green plant material (probably Potamogeton pectinatus) was abundant in July faeces. There were no clear seasonal trends in diet, perhaps because of the poor quality of most gut samples and variation between years in the seasonal patterns of abundance of different seeds and invertebrates. Ducklings fed mainly on invertebrates, especially chironomid adults and pupae, Coleoptera, Corixidae and ants. They consumed more green plant matter than seedsLe régime alimentaire de la Sarcelle marbrée Marmaronetta angustirostris a été étudié dans les marais du sud de l'Alicante, le site le plus important pour la population européenne de cette espèce globalement menacée. Nous avons analysé les contenus stomacaux de 64 individus volants, récoltés entre le 16 juin et le 24 novembre, de 1992 à 2000, ainsi que de 31 canetons (29 de la classe d'âge la, récemment éclos), obtenus entre le 18 mai et le 16 juillet, de 1994 à 1998. Les canetons décédèrent après leur récupération dans un conduit d'irrigation bétonné et tous les individus volants, sauf quatre, périrent lors de divers épisodes de mortalité généralisée. Nous avons aussi analysé les échantillons fécaux de 20 oiseaux volants recueillis en juillet-août, en 1999 et 2000, plus ceux correspondant à cinq couvées récupérées dans le conduit d'irrigation. Les graines (72 % en volume) et les invertébrés (21 %) dominaient dans les gésiers des oiseaux volants. Les graines de Scirpus litoralis (43 % en volume), principalement consommées quand elles flottent à la surface de l'eau, constituaient l'item alimentaire le plus important. L'importance des invertébrés a probablement été sous-estimée en raison de la mauvaise qualité des contenus stomacaux. Les larves et les pupes de chironomes, les Corixidés et leurs œufs, les fourmis, les ostracodes et les amphipodes étaient, en volume, les invertébrés les plus abondants. Les végétaux verts (probablement Potamogeton pectinatus) étaient abondants dans les fèces de juillet. Aucune saisonalité alimentaire n'a été clairement détectée, peut-être en raison de la qualité médiocre de la plupart des échantillons stomacaux et des variations interannuelles des patrons saisonniers d'abondance des divers graines et invertébrés. Les canetons se nourrissent principalement d'invertébrés, en particulier d'adultes et de pupes de chironomes, de Coléoptères, de Corixidés et de fourmis. Ils consomment plus de végétaux verts que de graines