共查询到20条相似文献,搜索用时 15 毫秒
1.
J. D. Anadón A. Giménez I. Pérez M. Martínez M. A. Esteve 《Biodiversity and Conservation》2006,15(7):2287-2299
As a result of human activities, natural Mediterranean landscapes (including agro-ecosystems) are characterised by a mosaic-like
structure with habitat-patches at different successional stages. These systems have high biodiversity levels and are home
to a large number of species protected by European laws whose habitats should be adequately managed. In the present work,
we study habitat use from an applied point of view in the spur-thighed tortoise Testudo graeca, an endangered reptile present in semi-arid Mediterranean agro-ecosystems. Results show that, at a landscape scale, the species
selects simplified vegetation structures and includes in its home range re-colonisation shrubland and small non-irrigated
fields. Within the home range, habitat selection patterns vary and areas with higher vegetation cover and complexity are selected.
Detected patterns are discussed in terms of the ecological requirements of the species and with a hierarchical view of resources
and conditions. The implications of our findings for habitat management aimed at the conservation of the species are also
discussed. 相似文献
2.
An improved understanding of the relative influences of climatic and landscape controls on multiple fire regime components is needed to enhance our understanding of modern fire regimes and how they will respond to future environmental change. To address this need, we analyzed the spatio-temporal patterns of fire occurrence, size, and severity of large fires (> 405 ha) in the western United States from 1984–2010. We assessed the associations of these fire regime components with environmental variables, including short-term climate anomalies, vegetation type, topography, and human influences, using boosted regression tree analysis. Results showed that large fire occurrence, size, and severity each exhibited distinctive spatial and spatio-temporal patterns, which were controlled by different sets of climate and landscape factors. Antecedent climate anomalies had the strongest influences on fire occurrence, resulting in the highest spatial synchrony. In contrast, climatic variability had weaker influences on fire size and severity and vegetation types were the most important environmental determinants of these fire regime components. Topography had moderately strong effects on both fire occurrence and severity, and human influence variables were most strongly associated with fire size. These results suggest a potential for the emergence of novel fire regimes due to the responses of fire regime components to multiple drivers at different spatial and temporal scales. Next-generation approaches for projecting future fire regimes should incorporate indirect climate effects on vegetation type changes as well as other landscape effects on multiple components of fire regimes. 相似文献
3.
In the southern California foothills and mountains, pronounced and complex topographic gradients support fire regimes that
vary over short distances. We used LANDIS, a spatially explicit landscape model of disturbance and plant succession, to examine
the resilience of dominant plant species, representing different disturbance response strategies, to the effect of varying
fire rotation intervals (FRI). The simulated fire regimes represented natural, current and very long FRIs for the foothill
shrublands less than 1,400 m (90, 30 and 150 years) and montane forest greater than 1400 m (30, 150, 500 years). The 30-year
FRI allowed obligate resprouting shrubs to dominate over obligate seeders, whereas the 90-year FRI resulted in a stable spatial
distribution of both of these shrub functional types. This is consistent with the literature that suggests that shifts in
shrubland composition are most likely to result from human-caused increases in fire frequency at the low-elevation urban-wildland
interface. An ecotone conifer, Pinus coulteri, showed dramatic shifts in distribution under different FRIs, and retreated to the portion of the landscape representing
its temporal regeneration niche. Both low and high frequency fire maintained the fire tolerant dominant pine (P. jeffreyi) in the montane zone. This contradicts the literature that suggests that a high frequency ground fire regime is required
for the persistence of a pine-dominated forest, but is consistent with studies showing that conifer forests in the western
U.S. have experienced, and are resilient to, a broad range of natural FRIs that include low frequency, high intensity crown
fires. 相似文献
4.
Nicholas Smith 《The Australian journal of anthropology》1999,10(3):288-305
This paper looks at recent attention given to feral cats in Australia, particularly focusing on their symbolic status in eco-nationalist discourses. Australian eco-nationalism is a specific blend of environmentalist and patriotic sentiments which, in an exaggerated way, positions the feral cat as a rapacious European invader predating on native wild life. This vilification of the cat can be related to much earlier forms of (mainly European) symbolism associating the creature with femininity and evil, which I illustrate by looking at the manner in which the feral cat is opposed to the masculinised Australian wild dog—the dingo. I argue that the recent surfacing of this totemic opposition between ‘the howl and the pussycat’ is related to an eco-nationalist sense of place which simultaneously recognises and denies that the human colonisation of Australia was (and is) a form of feral invasion. 相似文献
5.
Mark J. Farnworth Nicholson G. Dye Natasha Keown 《Journal of applied animal welfare science : JAAWS》2013,16(2):180-188
Pinpointing and safeguarding the welfare status of domestic cats is problematic, especially in New Zealand where cats are introduced predators with significant impact on indigenous fauna. Usually the identification of welfare status depends on conservational, legal, and public attitudes that are often contrasting. Cats may rapidly transgress definitions placed on them, confounding attempts to categorize them. In 1 generation, cats can move from a human-dependent state (“stray” or “companion”) to wild (“feral”). Often this categorization uses arbitrary behavioral and or situational parameters; consequent treatment and welfare protection for these cats are similarly affected. Terminology used to describe cats is not equitable across research. However, the New Zealand Animal Welfare (Companion Cats) Code of Welfare 2007 seeks to create a new definition of the terms companion, stray, and feral. It distinguishes between cats who live within and without human social constructs. This legislation mandates that cats in human environments or indirectly dependent on humans cannot be classified as feral. Such definitions may prove vital when safeguarding the welfare of free-living domestic cats and cat colonies. 相似文献
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Bernardi Rafael E. Staal Arie Xu Chi Scheffer Marten Holmgren Milena 《Ecosystems》2019,22(7):1457-1465
Ecosystems - Livestock grazing is the most extensive human land use and one of the key drivers of the conversion of tropical forests into grasslands. Livestock effects on vegetation structure are... 相似文献
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Carol de Jong Hume Field Anson Tagtag Tom Hughes Dina Dechmann Sarah Jayme Jonathan Epstein Craig Smith Imelda Santos Davinio Catbagan Mundita Lim Carolyn Benigno Peter Daszak Scott Newman 《PloS one》2013,8(11)
Species of Old World fruit-bats (family Pteropodidae) have been identified as the natural hosts of a number of novel and highly pathogenic viruses threatening livestock and human health. We used GPS data loggers to record the nocturnal foraging movements of Acerodon jubatus, the Golden-crowned flying fox in the Philippines to better understand the landscape utilisation of this iconic species, with the dual objectives of pre-empting disease emergence and supporting conservation management. Data loggers were deployed on eight of 54 A. jubatus (two males and six females) captured near Subic Bay on the Philippine island of Luzon between 22 November and 2 December 2010. Bodyweight ranged from 730 g to 1002 g, translating to a weight burden of 3–4% of bodyweight. Six of the eight loggers yielded useful data over 2–10 days, showing variability in the nature and range of individual bat movements. The majority of foraging locations were in closed forest and most were remote from evident human activity. Forty-six discrete foraging locations and five previously unrecorded roost locations were identified. Our findings indicate that foraging is not a random event, with the majority of bats exhibiting repetitious foraging movements night-to-night, that apparently intact forest provides the primary foraging resource, and that known roost locations substantially underestimate the true number (and location) of roosts. Our initial findings support policy and decision-making across perspectives including landscape management, species conservation, and potentially disease emergence. 相似文献
10.
John T. Delaney Raymond A. Moranz Diane M. Debinski David M. Engle James R. Miller 《PloS one》2016,11(11)
In grasslands, overgrazing by domestic livestock, fertilization, and introduction of exotic forage species leads to plant communities consisting of a mixture of native and exotic species. These degraded grasslands present a problem for land managers, farmers, and restoration ecologists concerned with improving biodiversity while continuing to use the land for livestock production. Here we assessed the response of butterfly and plant community composition to the use of fire and moderate grazing by domestic cattle on degraded grasslands dominated by exotic plants. We evaluated change by comparing experimental pastures to two reference sites that were grasslands dominated by native plants. We used two burning and grazing treatments: 1) patch-burn graze, a heterogeneously managed treatment, where one third of the pasture is burned each year and cattle have free access to the entire pasture, and 2) graze-and-burn, a homogenously managed treatment, where the entire pasture is grazed each year and burned in its entirety every three years. We tested for change in the butterfly and plant community composition over seven years using Bray-Curtis dissimilarity measures. Over the course of seven years, degraded pastures in both treatments became more similar to reference sites with respect to the butterfly and plant communities. Only two butterfly species and two plant functional guilds exhibited significant linear trends over time, with varying responses. Compositional changes in both the butterfly and plant communities indicate that the use of moderate grazing and fire may shift butterfly and plant communities of exotic-dominated grasslands to be more similar to reference tallgrass prairies over time. 相似文献
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The association of the exotic fire ant, Solenopsis invicta with man-modified habitats has been amply demonstrated, but the fate of such populations if ecological succession proceeds has rarely been investigated. Resurvey of a fire ant population in a longleaf pine plantation after 25 years showed that the recovery of the site from habitat disturbance was associated with a large fire ant population decline. Most of the persisting colonies were associated with the disturbance caused by vehicle tracks. In a second study, mature monogyne fire ant colonies that had been planted in experimental plots in native groundcover of the north Florida longleaf pine forest had mostly vanished six years later. These observations and experiments show that S. invicta colonies rarely persist in the native habitat of these pine forests, probably because they are not replaced when they die. A single site harbored a modest population of polygyne fire ants whose persistence was probably facilitated by reproduction through colony fission. 相似文献
13.
James R. Welch 《Human ecology: an interdisciplinary journal》2014,42(1):47-59
Conservation attention to indigenous hunting with fire in the cerrado largely focuses on sustainability as construed in scientific terms rather than according to indigenous points of view. Towards the goal of reframing the debate in terms more congruent with indigenous perspectives, I address how the Xavante (A’uw?) view ritualized and collective hunting, including hunting with fire, as indispensable means of acquiring gifts by which to celebrate important events, express feelings of respect and gratitude towards others, promote positive social values among male youth, and maintain the group’s ethnic identity. In particular, ritualized exchanges of game meat are necessary and culturally appropriate means of expressing esteem for others at some of life’s most important moments. For the Xavante, the social imperative to give and receive gifts of meat during weddings and initiation ceremonies motivates efforts to maintain the collective hunting with fire tradition in a manner that ensures its long term environmental viability. 相似文献
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Feral pigs (Sus scrofa) are an invasive species that disrupt ecosystem functioning throughout their introduced range. In tropical environments, feral pigs are associated with predation and displacement of endangered species, modification of habitat, and act as a vector for the spread of exotic vegetation and disease. Across many parts of their introduced range, the diet of feral pigs is poorly known. Although the remote location and difficult terrain of far north Queensland makes observing feral pig behavior difficult, feral pigs are perceived to seek refuge in World Heritage tropical rainforests and seasonally 'crop raid' into lowland sugarcane crops. Thus, identifying how feral pigs are using different components of the landscape is important to the design of management strategies. We used the stable isotope composition of captured feral pigs to determine the extent of rainforest and sugarcane habitat usage. Recently grown hair (basal hair) from feral pigs captured in remote rainforest indicated pigs met their dietary needs solely within this habitat. Stable carbon and nitrogen isotope values of basal hair from feral pigs captured near sugarcane plantations were more variable, with some individuals estimated to consume over 85% of their diet within a sugarcane habitat, while a few consumed as much as 90% of their diet from adjacent forested environments. We estimated whether feral pigs switch habitats by sequentially sampling δ(13)C and δ(15)N values of long tail hair from a subset of seven captured animals, and demonstrate that four of these individuals moved between habitats. Our results indicate that feral pigs utilize both sugarcane and forest habitats, and can switch between these resources. 相似文献
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Understanding the impact of grazing intensity on grassland production and soil fertility is of fundamental importance for grassland conservation and management. We thus compared three types of alpine steppe management by studying vegetation traits and soil properties in response to three levels of grazing pressure: permanent grazing (M1), seasonal grazing (M2), and grazing exclusion (M3) in the alpine steppe in Xainza County, Tibetan Plateau. The results showed that community biomass allocation did not support the isometric hypothesis under different grassland management types. Plants in M1 had less aboveground biomass but more belowground biomass in the top soil layer than those in M2 and M3, which was largely due to that root/shoot ratios of dominant plants in M1 were far greater than those in M2 and M3. The interramet distance and the tiller size of the dominant clonal plants were greater in M3 than in M1 and M2, while the resprouting from rhizome buds did not differ significantly among the three greezing regimes. Both soil bulk density and soil available nitrogen in M3 were greater than in M1 at the 15–30 cm soil depth (P = 0.05). Soil organic carbon and soil total nitrogen were greater in M3 than in M1 and M2 (P = 0.05). We conclude that the isometric hypothesis is not supported in this study and fencing is a helpful grassland management in terms of plant growth and soil nutrient retention in alpine steppe. The extreme cold, scarce precipitation and short growing period may be the causation of the unique plant and soil responses to different management regimes. 相似文献
18.
Mark W. Chynoweth Christopher A. Lepczyk Creighton M. Litton Steven C. Hess James R. Kellner Susan Cordell 《PloS one》2015,10(3)
Advances in wildlife telemetry and remote sensing technology facilitate studies of broad-scale movements of ungulates in relation to phenological shifts in vegetation. In tropical island dry landscapes, home range use and movements of non-native feral goats (Capra hircus) are largely unknown, yet this information is important to help guide the conservation and restoration of some of the world’s most critically endangered ecosystems. We hypothesized that feral goats would respond to resource pulses in vegetation by traveling to areas of recent green-up. To address this hypothesis, we fitted six male and seven female feral goats with Global Positioning System (GPS) collars equipped with an Argos satellite upload link to examine goat movements in relation to the plant phenology using the Normalized Difference Vegetation Index (NDVI). Movement patterns of 50% of males and 40% of females suggested conditional movement between non-overlapping home ranges throughout the year. A shift in NDVI values corresponded with movement between primary and secondary ranges of goats that exhibited long-distance movement, suggesting that vegetation phenology as captured by NDVI is a good indicator of the habitat and movement patterns of feral goats in tropical island dry landscapes. In the context of conservation and restoration of tropical island landscapes, the results of our study identify how non-native feral goats use resources across a broad landscape to sustain their populations and facilitate invasion of native plant communities. 相似文献
19.
粉苞苣属(Chondrilla L.)植物是菊科多年生草本,约25种,主要分布中亚、北亚和欧洲。我国有10种,主要分布在新疆北部。通过对粉苞菊的生境、分布调查,得知粉苞苣属植物在新疆分布非常广泛,主要生长于砾石地和沙地,在公路两旁有大量的自然分布。粉苞苣属植物花期长,花色鲜艳,姿态优雅,是一种难得的野生观赏植物;同时,粉苞苣属植物具有耐盐碱、抗旱及耐贫瘠的特性,以其强盛的适应性和繁殖能力生长于荒漠、戈壁地带,是园林绿地、公路铁路和荒山荒坡绿化的理想植物。 相似文献
20.
After rainfall and soils, fire and herbivory are two of the main determinants of savanna ecosystems. Although the interactive effects of fire and herbivores on soil and vegetation are widely acknowledged few studies have addressed these two factors in concert, and none of the studies has focused on the Kalahari sand system. We experimentally studied how annual late dry season fires and grazing affect herbaceous plant species composition, above- and belowground biomass, and soil and grass nutrient concentrations in the nutrient-poor semi-arid Kalahari system in northern Botswana. Four treatments (fire, grazing, fire + grazing, and no-fire–no-grazing) were applied for two consecutive years in the late dry season. Plant species composition was affected by treatment and year. The no-fire–no-grazing treatment was distinctly different from all the other treatments in terms of species composition. Beta diversity was lower on the fire treatment and grazing treatment, but not where fire and grazing were combined. Fire and grazing alone or in combination did not have a substantial effect on biomass, soil and plant nutrients or plant species alpha diversity. Plant nitrogen was the only element that differed between treatments, with high concentrations on all the grazed treatments in the first year and low levels on the fire-alone treatment during the second year. The results show that fire and grazing mainly affect species composition and large-scale biodiversity patterns as indicated by the no-fire–no-grazing treatment being distinctly different from other treatments, suggesting the evolutionary adaptation of this dystrophic Kalahari sand system to herbivory and fire. 相似文献