2,912 research outputs found

    Fire-mediated niche-separation between two sympatric small mammal species

    Full text link
    © 2014 Ecological Society of Australia. Fire is a key ecological process influencing the population dynamics of small mammals. Whilst shifting competitive advantage amongst small mammal species following a single fire event is well-documented, there has been little investigation of the potential influence of fire frequency on small mammal interspecific interactions. In this study, we investigated the effect of fire frequency on the abundance of two small dasyurid mammals, Antechinus stuartii and A. flavipes, which occur sympatrically in some parts of their range. The two antechinus species are known to have different habitat preferences, so it is possible that fire regimes may promote their coexistence in areas of sympatry by altering vegetation structure. To investigate this possibility, we estimated the abundance of both species using replicate sites which differed in the number of times burnt (1-4) during the last four decades, but with identical time-since-fire. Proportionally, we captured greater numbers of A. stuartii in less frequently burnt sites and greater numbers of A. flavipes in more-frequently burnt sites. Hence, fire may mediate niche-separation between these two species. To clarify further this pattern of response to fire frequency, we investigated which structural habitat variables differed between fire frequencies, and compared antechinus abundances with structural vegetation characteristics. We found a trend for lower ground cover density under higher fire frequencies. This offers one potential explanation of the patterns of abundance that we observed. Our study provided insights into the complexities of small mammal responses to fire, and strongly suggests that fire could mediate competitive interactions between species

    Variation of prey responses to cues from a mesopredator and an apex predator

    Full text link
    © 2014 Ecological Society of Australia 39 7 November 2014 10.1111/aec.12138 Original Articles Original Article © 2014 The Authors. Austral Ecology. Detection and avoidance of predator cues can be costly, so it is important for prey to balance the benefits of gaining food against the costs of avoiding predators. Balancing these factors becomes more complicated when prey are threatened by more than one type of predator. Hence, the ability to recognize species-specific predator odours and prioritize behaviours according to the level of risk is essential for survival. We investigated how rock rats, Zyzomys spp. modify their foraging behaviour and giving-up density (GUD) in the presence of an apex predator, the dingo Canis dingo, a mesopredator, the northern quoll Dasyurus hallucatus, a herbivore, the rock wallaby Petrogale brachyotis as a pungency control and water as a procedural control. Both dingoes and quolls consume rock rats, but because quolls can enter small crevices inhabited by rock rats, they pose a greater threat to rock rats than dingoes. Rock rats demonstrated a stronger avoidance to quoll odour than dingo odour, and no avoidance of the pungency control (rock wallaby) and the procedural control (water). GUD values declined significantly over the duration of the study, but did not differ between odour treatments. Our results support the hypothesis that prey vary behaviour according to perceived predator threat, and show stronger responses to potentially more dangerous predators

    Carrion subsidies provided by fishermen increase predation of beach-nesting bird nests by facultative scavengers

    Full text link
    © 2014 The Zoological Society of London. Many predators are also scavengers that feed on carrion and human refuse. Therefore, the availability of carrion can elevate the abundance or activity of facultative scavengers, amplifying predation pressure on prey. On Australian beaches, fishermen often discard fish carcasses that could attract facultative scavengers, both native, such as Australian ravens Corvus coronoides, and invasive, such as European red foxes Vulpes vulpes, and result in elevated rates of predation on wildlife. We tested whether the presence of fish carcasses increased the risk of depredation for nearby nests of beach-nesting birds by deploying artificial nests in 12 subsidized and 12 control patches, spaced 1 km apart, on a beach. We placed a fish carcass in each subsidized patch, but not at control patches. In each patch, we placed two artificial nests, which resembled red-capped plover Charadrius ruficapillus nests, 80 m apart and 40m from carcasses at subsidized patches. Nest predators were identified from tracks and predator activity near subsidized and control nests was measured by counting tracks crossing a straight transect (220m). The activity of a native predator, the Australian raven, was 17 times higher near (<80m) nests with fish carcasses than nests without carcasses. After 72h, 96% of nests near carcasses were depredated compared with 30% of nests without carcasses. Ravens were identified as the culprit for 80% of depredated nests. Although other predators were present in the study area, they did not depredate artificial nests in this experiment. Previous studies have highlighted the effects of permanent and/or large-scale food resources on scavenger abundance and impact. A key management implication of our study is that even small, sparsely distributed, temporally irregular food subsidies, provided by humans, can elevate the activity and predatory impacts of facultative scavengers

    Movements and Habitat Use of an Endangered Snake, Hoplocephalus bungaroides (Elapidae): Implications for Conservation

    Get PDF
    A detailed understanding of how extensively animals move through the landscape, and the habitat features upon which they rely, can identify conservation priorities and thus inform management planning. For many endangered species, information on habitat use either is sparse, or is based upon studies from a small part of the species' range. The broad-headed snake (Hoplocephalus bungaroides) is restricted to a specialized habitat (sandstone outcrops and nearby forests) within a small geographic range in south-eastern Australia. Previous research on this endangered taxon was done at a single site in the extreme south of the species' geographic range. We captured and radio-tracked 9 adult broad-headed snakes at sites in the northern part of the species' distribution, to evaluate the generality of results from prior studies, and to identify critical habitat components for this northern population. Snakes spent most of winter beneath sun-warmed rocks then shifted to tree hollows in summer. Thermal regimes within retreat-sites support the hypothesis that this shift is thermally driven. Intervals between successive displacements were longer than in the southern snakes but dispersal distances per move and home ranges were similar. Our snakes showed non-random preferences both in terms of macrohabitat (e.g., avoidance of some vegetation types) and microhabitat (e.g., frequent use of hollow-bearing trees). Despite many consistencies, the ecology of this species differs enough between southern and northern extremes of its range that managers need to incorporate information on local features to most effectively conserve this threatened reptile. © 2013 Croak et al

    Latinx Children’s Push and Pull of Spanish Literacy and Translanguaging

    Get PDF
    We explored 19 Latinx children’s literacies in Spanish and translanguaging by asking, “What are Latinx children’s experiences and beliefs regarding Spanish and translanguaging reading and writing? How do tutorial staff and teacher candidates (TCs) help the youth to resist hegemonic and bracketing practices of English-only?” This study took place in a South Texas tutorial agency, where children voluntarily attended for after-school homework help. Data sources consisted of questionnaires, interviews, focus groups, hobby essays, and newsletter articles. Most children reported negative school-related language experiences and expressed dislike and unease regarding Spanish and translanguaging reading and writing, although they lived less than 10 miles from the Mexico border. However, two tutorial staff and 15 TCs provided counter narratives and modeled that Spanish and translanguaged (hybrid) reading and writing are neither wrong nor difficult. Schools’ accountability pressures and the U.S. socio-political milieu move language to the center (centripetal forces), while forces that resist normalization are centrifugal. Implications relate to how neighborhood educational centers, TCs, and classroom teachers can help subaltern youth to resist centripetal language forces

    Developing and Integrating the Management of Elder Abuse in Primary Practice: A Case Study Using A Web-Based CME Course Format

    Get PDF
    Introduction: As the population in the United States continues to age, more attention in primary practice settings is now devoted toward managing the care of the elderly. The occurrence of elder abuse is a growing problem. It is a condition many professionals in primary care may be ill prepared with the knowledge or resources to identify and manage. [See PDF for complete abstract

    Original investigatiOn efficacy of a DvD-Based smoking Cessation intervention for african americans

    Get PDF
    aBstraCt introduction: Previous research suggests that African American smokers may have improved outcomes if interventions are culturally specific. However, few interventions sufficiently address the unique needs of this population in a format with large reach potential. The purpose of this study was to test the efficacy of a newly developed digital video disc (DVD)-based cessation intervention targeting African Americans

    Degradation mechanism of hybrid tin-based perovskite solar cells and the critical role of tin (IV) iodide

    Get PDF
    Tin perovskites have emerged as promising alternatives to toxic lead perovskites in next-generation photovoltaics, but their poor environmental stability remains an obstacle towards more competitive performances. Therefore, a full understanding of their decomposition processes is needed to address these stability issues. Herein, we elucidate the degradation mechanism of 2D/3D tin perovskite films based on (PEA)0.2(FA)0.8SnI3 (where PEA is phenylethylammonium and FA is formamidinium). We show that SnI4, a product of the oxygen-induced degradation of tin perovskite, quickly evolves into iodine via the combined action of moisture and oxygen. We identify iodine as a highly aggressive species that can further oxidise the perovskite to more SnI4, establishing a cyclic degradation mechanism. Perovskite stability is then observed to strongly depend on the hole transport layer chosen as the substrate, which is exploited to tackle film degradation. These key insights will enable the future design and optimisation of stable tin-based perovskite optoelectronics

    The Effects of Two Planning Interventions on the Oral Health Behavior of Iranian Adolescents: A Cluster Randomized Controlled Trial.

    Get PDF
    PURPOSE: The aim of this study was to investigate the effectiveness of a planning intervention (specifying when, where, and how to act) and an implementation intention intervention (specifying the same in the format of an if-then plan) in increasing self-reported brushing in adolescents. METHODS: The study adopted a cluster randomized controlled trial design, and 1158 students in 48 schools were randomized to planning, implementation intention, or active control conditions. After baseline assessment, all participants received a leaflet containing information and recommendations on oral health and instructions on correct brushing behavior. After reading the leaflets, they were provided with a toothbrush and toothpaste plus a calendar in which to record their brushing. Participants in the planning condition and in the implementation intention condition also received instructions to form specific plans regarding brushing behavior. Self-reported brushing, perceived behavioral control, self-monitoring, intention, frequency of planning, oral health-related quality of life, and dental plaque and periodontal status were measured 1 and 6 months later. RESULTS: Both intervention conditions showed a significant improvement in the frequency of self-reported brushing, self-monitoring, frequency of planning, intention, perceived behavioral control, plaque index, periodontal health, and oral health-related quality of life compared to the control condition at both follow-ups. Comparing the two intervention conditions revealed that adolescents who received the implementation intention intervention had significantly greater improvement in the frequency of self-reported brushing, intention, frequency of planning, and periodontal health than those in planning condition. CONCLUSIONS: Taken together, the findings suggest that forming implementation intentions as well as planning has the potential to increase dental self-reported brushing rates in adolescents, but that forming implementation intentions has the strongest impact on dental hygiene behavior and is, therefore, recommended. TRIAL REGISTRATION NUMBER: The trial was registered with the ClinicalTrials.gov database (NCT02066987) https://www.clinicaltrials.gov/ct2/show/NCT02066987
    corecore