30 research outputs found

    Influence of hatching order and brood size on growth in jackass penguins

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    Jackass penguins Spheniscus demersus hatch two different-sized eggs asynchronously: the second-hatched chick, being, on average, 59% of the weight of the first-hatched chick on hatching. We examined the effect of hatching order on growth rates of mass, culmen length and culmen depth by comparing: (i) growth rates of first-and second-hatched chicks, and (ii) chicks from experimentally synchronized broods to chicks from normal asynchronous broods. Only growth rates in mass showed significant variation. Within a brood, B chicks grew more slowly than A chicks. The effect of synchronizing a brood was to lower the growth rate of both chicks to that of a B chick, suggesting that equal-sized siblings feed less efficiently. Chicks hatching from larger A eggs, that had been synchronized for age and size with chiçks from B eggs, did not grow faster, indicating that chicks hatching from A and B eggs do not have intrinsically different growth rates. Single-chick nests result usually from egg infertility. Singletons showed only a non-significant trend towards faster growth in mass than offspring in two-chick broods, even though food availability in one-chick nests should be better than in two-chick nests. Overall, hatching order had more impact on growth rates of mass than did brood size or egg dimensions

    Community Attitudes and Practices of Urban Residents Regarding Predation by Pet Cats on Wildlife: An International Comparison

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    International differences in practices and attitudes regarding pet cats\u27 interactions with wildlife were assessed by surveying citizens from at least two cities in Australia, New Zealand, the UK, the USA, China and Japan. Predictions tested were: (i) cat owners would agree less than non-cat owners that cats might threaten wildlife, (ii) cat owners value wildlife less than non-cat owners, (iii) cat owners are less accepting of cat legislation/restrictions than non-owners, and (iv) respondents from regions with high endemic biodiversity (Australia, New Zealand, China and the USA state of Hawaii) would be most concerned about pet cats threatening wildlife. Everywhere non-owners were more likely than owners to agree that pet cats killing wildlife were a problem in cities, towns and rural areas. Agreement amongst nonowners was highest in Australia (95%) and New Zealand (78%) and lowest in the UK (38%). Irrespective of ownership, over 85% of respondents from all countries except China (65%) valued wildlife in cities, towns and rural areas. Non-owners advocated cat legislation more strongly than owners except in Japan. Australian non-owners were the most supportive (88%), followed by Chinese non-owners (80%) and Japanese owners (79.5%). The UK was least supportive (non-owners 43%, owners 25%). Many Australian (62%), New Zealand (51%) and Chinese owners (42%) agreed that pet cats killing wildlife in cities, towns and rural areas was a problem, while Hawaiian owners were similar to the mainland USA (20%). Thus high endemic biodiversity might contribute to attitudes in some, but not all, countries. Husbandry practices varied internationally, with predation highest where fewer cats were confined. Although the risk of wildlife population declines caused by pet cats justifies precautionary action, campaigns based on wildlife protection are unlikely to succeed outside Australia or New Zealand. Restrictions on roaming protect wildlife and benefit cat welfare, so welfare is a better rationale

    A Science-Based Policy for Managing Free-Roaming Cats

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    Free-roaming domestic cats (i.e., cats that are owned or unowned and are considered ‘at large’) are globally distributed non-native species that have marked impacts on biodiversity and human health. Despite clear scientific evidence of these impacts, free-roaming cats are either unmanaged or managed using scientifically unsupported and ineffective approaches (e.g., trap-neuter-release [TNR]) in many jurisdictions around the world. A critical first initiative for effective, science-driven management of cats must be broader political and legislative recognition of free-roaming cats as a non-native, invasive species. Designating cats as invasive is important for developing and implementing science-based management plans, which should include efforts to prevent cats from becoming free-roaming, policies focused on responsible pet ownership and banning outdoor cat feeding, and better enforcement of existing laws. Using a science-based approach is necessary for responding effectively to the politically charged and increasingly urgent issue of managing free-roaming cat populations

    Closing the Gap: Communicating to Change Gardening Practices in Support of Native Biodiversity in Urban Private Gardens

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    Private gardens collectively comprise the largest green space in most cities and the greatest potential for increasing the extent of wildlife-friendly and native-dominated habitat, improving the quality of ecosystem services, and providing opportunities for urban dwellers to reconnect with nature. Because attitudes and values driving landscape preferences in gardens are complex and often not conducive to biodiversity, and a gap exists between the possession of knowledge or values and the expression of pro-environmental behavior, facilitating change in gardening behavior is challenging. We attempted to improve knowledge and influence values, attitudes, and gardening behavior of 55 householders in favor of native biodiversity and environmentally friendly practices, through a two-way communication process, or interactive dialog, during a process of biodiversity documentation of their gardens. Informative feedback on their garden with a normative component was also provided. Despite being well educated and knowledgeable about common species at the start of the study, an increase in knowledge and shift in attitude was detected in 64% of householders: 40% reported a greater understanding of wildlife, and 26% made changes in their gardens, 13% to support native biodiversity. The normative component of our feedback information was of particular interest to 20% of householders. Because neighborhood norms influence gardening practices, changes adopted by a proportion of householders should be perpetuated across neighborhoods. The process of biodiversity assessment, dialog, and feedback was effective in improving knowledge of wildlife and native species, and stimulated a shift in attitude that resulted in native-friendly gardening practices. These changes were detected primarily through open self-report questions, rather than quantitative measures

    Native and exotic woody vegetation communities in domestic gardens in relation to social and environmental factors

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    Vegetation in private gardens contributes significantly to plant species richness and vegetation volume across urban areas. Drivers of garden diversity and structure are complex, reflecting the diversity of social, cultural, and socioeconomic characteristics of the householders who manage their gardens, as well as their predecessors. Here we investigate the woodiness of gardens, and focus on (1) the prevalence of native versus exotic woody plants and (2) the influence of characteristics of garden owners, the gardens, and their proximity to neighborhood green spaces to identify the degree to which these factors explain patterns in native and exotic woody species communities in entire (back and front) gardens in southern temperate New Zealand. We found few consistent patterns in structure in woody species community composition. Outlying gardens were characterized by low species richness and abundance. Thirty-seven species commonly occurred across most gardens: most of these were exotic. Twelve native species were common throughout most gardens. There was significant but weak matching to social and environmental variables: vegetated area, species knowledge, and education explained pattern in native communities, whereas vegetated area, species knowledge, and householder age explained variation in exotic communities. Native trees > 5 m tall occurred in only 58% of gardens. Tall tree density was 10/ha, and 29% of gardens lacked any trees > 5 m. Tree presence was weakly (positively) associated with extent and proximity of neighborhood green space. We suggest that the legacy of previous owners' gardening practices is important to consider when identifying drivers of garden plant community structure

    An evaluation of the accuracy and performance of lightweight GPS collars in a suburban environment.

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    The recent development of lightweight GPS collars has enabled medium-to-small sized animals to be tracked via GPS telemetry. Evaluation of the performance and accuracy of GPS collars is largely confined to devices designed for large animals for deployment in natural environments. This study aimed to assess the performance of lightweight GPS collars within a suburban environment, which may be different from natural environments in a way that is relevant to satellite signal acquisition. We assessed the effects of vegetation complexity, sky availability (percentage of clear sky not obstructed by natural or artificial features of the environment), proximity to buildings, and satellite geometry on fix success rate (FSR) and location error (LE) for lightweight GPS collars within a suburban environment. Sky availability had the largest affect on FSR, while LE was influenced by sky availability, vegetation complexity, and HDOP (Horizontal Dilution of Precision). Despite the complexity and modified nature of suburban areas, values for FSR (mean= 90.6%) and LE (mean = 30.1 m) obtained within the suburban environment are comparable to those from previous evaluations of GPS collars designed for larger animals and within less built-up environments. Due to fine-scale patchiness of habitat within urban environments, it is recommended that resource selection methods that are not reliant on buffer sizes be utilised for selection studies

    Mean location error (µLE ± SD) for each HDOP value.

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    <p>Mean location error (µLE ± SD) for each HDOP value for lightweight GPS collars across all suburban habitats and sky availability classes, Dunedin.</p

    Descriptions of the five urban habitat types in which common brushtail possums (<i>Trichosurus vulpecula</i>) were surveyed in Dunedin, New Zealand produced by Freeman and Buck [44].

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    <p>Descriptions of the five urban habitat types in which common brushtail possums (<i>Trichosurus vulpecula</i>) were surveyed in Dunedin, New Zealand produced by Freeman and Buck <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058422#pone.0058422-Freeman1" target="_blank">[44]</a>.</p
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