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1.
Samantha A. Setterfield Natalie A. Rossiter‐Rachor Lindsay B. Hutley Michael M. Douglas Richard J. Williams 《Diversity & distributions》2010,16(5):854-861
Aim This study aimed to quantify changes in fire severity resulting from the invasion of Australia’s tropical savannas by the African grass Andropogon gayanus Kunth. (gamba grass). Location Mesic savannas of the Northern Territory, Australia. Method Byram’s fire‐line intensity (If), fuel load and architecture, and two post‐fire indicators of fire intensity – scorch height (SH) and char height (CH) of woody vegetation – were determined for fires in native grass savanna and A. gayanus invaded savanna. Leaf scorch is the height at which the fire’s radiant heat browns leaf tissue, and leaf char is the height that radiant heat blackens or consumes leaf tissue and provides an indirect measure of flame height. These data, and 5 years of similar data collected from the Kapalga Fire Project in Kakadu National Park, were used to develop empirical relationships between If and the post‐fire indices of fire intensity. Results A relationship between A. gayanus If and SH could not be developed because complete canopy scorch occurred in most A. gayanus fires, even at low If. In contrast, A. gayanus If was strongly correlated with CH. This empirical relationship was substantially different from that for native grass fires. For a given If, there was a significantly greater CH in invaded sites. This increase in radiant heat is attributable to the increased biomass (mean 3.6 t ha?1 in native grasses compared to 11.6 t ha?1 in A. gayanus) and height (approximately 0.5 m in native grasses compared to 4 m in A. gayanus) of the standing fine fuel. Main conclusion Andropogon gayanus invasion resulted in substantial changes in fire behaviour. This has important regional implications owing to the current (10,000–15,000 km2) and predicted (380,000 km2) area of invasion and the negative consequences for the native savanna biota that has evolved with frequent but relatively low‐intensity fire. 相似文献
2.
N. A. Rossiter-Rachor S. A. Setterfield M. M. Douglas L. B. Hutley G. D. Cook 《Ecosystems》2008,11(1):77-88
Invasive alien grasses can substantially alter fuel loads and fire regimes which could have significant consequences for fire-mediated
nutrient losses. The effects of the alien grass Andropogon gayanus Kunth. (Gamba grass) on fire-mediated nutrient losses was evaluated in Australia’s tropical savannas. Losses of macronutrients
during fire were determined by comparing the nutrient pools contained in the fine fuel before fire and in the ash after fire.
Pre-fire grass nutrient pools were significantly higher in A. gayanus plots than in native grass plots for all nutrients measured (N, P, K, S, Ca, and Mg). Nutrient losses were substantially
higher in A. gayanus plots, with 113% higher losses for N, 80% for P, 56% for K, 63 for S, 355% for Ca, and 345% for Mg. However, only losses
of N and Mg varied significantly between grass types. A simplified savanna ecosystem nutrient budget estimated that A. gayanus fires led to the net N loss of 20 kg ha−1 y−1. This is a conservative estimate because total fuel loads were relatively low (7.85 t ha−1) for A. gayanus invaded plots leading to a relatively moderate intensity fire (6,408 kW m−1). Higher A. gayanus fuel loads and fire intensities could potentially lead to losses of up to 61.5 kg N ha−1 from the grass fuel. Over the long term, this is likely to lead to depletion of soil nutrients, particularly N, in the already
low-fertility tropical savanna soils. 相似文献
3.
Anne-Christine Monnet Maria S. Vorontsova Rafaël H. A. Govaerts Jens-Christian Svenning Brody Sandel 《Ecography》2020,43(9):1373-1385
The global distribution of exotic species is the result of abiotic, biotic and dispersal filtering processes that shape the movement and success of species outside their native range. In this study we aim to understand how these filtering processes drive the fluxes of grass species among regions, the factors that influence which species establish outside of their native range, and where they do so. We used national and subnational checklists of native and introduced grass species to determine the extent to which each region was a source or recipient of exotic grass species. We asked how species traits may distinguish those grass species that have naturalized outside their native range from those that have not, and how environmental conditions are related to the distribution of exotic grass species. We found that exotic grass establishment is shaped by an array of factors including characteristics of regions, traits of species and their interactions. Regions with a longer history of human occupation and larger numbers of native grass species were generally the most important sources of exotic species. Global flows of species were mostly driven by a climate match between the native and exotic ranges, but were also highly asymmetric, with regions with recent human arrival being the major hosts of exotic grass species. Tall, annual and C4 grass species exhibited particularly high probabilities of establishment outside their native range. Despite the idiosyncrasy and stochasticity characteristic of exotic species establishment, this biogeographical analysis revealed important generalities across this large plant group. Our results suggest that grass species that have co-occurred with humans for a longer time may be better adapted to living in anthropogenic landscapes, explaining the global asymmetry in species introductions. 相似文献
4.
Abstract. The common waxbill Estrilda astrild was first introduced to Portugal from Africa in 1964, and has spread across much of the country and into Spain. We modelled the expansion of the common waxbill on a 20 × 20 km UTM grid in 4‐year periods from 1964 to 1999. The time variation of the square root of the occupied area shows that this expansion process is stabilizing in Portugal, and reasons for this are discussed. Several methods used to model biological expansions are not appropriate for the present case, because little quantitative data are available on the species ecology and because this expansion has been spatially heterogeneous. Instead, colonization on a grid was modelled as a function of several biophysical and spatio‐temporal variables through the fitting of a multivariate autologistic equation. This approach allows examination of the underlying factors affecting the colonization process. In the case of the common waxbill it was associated positively with its occurrence in adjacent cells, and affected negatively by altitude and higher levels of solar radiation. 相似文献
5.
《生物多样性》编辑部 《生物多样性》2014,22(1):112
<正>2013年度,以下专家为《生物多样性》审阅稿件,在此向大家致以深切的谢意!正是有了各位专家认真、细致、及时地审阅稿件,才保障了刊物的学术质量,缩短了稿件的处理周期,从而帮助刊物赢得更多读者和作者的信赖。 相似文献
6.
新西兰鸟类入侵成功的有关因素 总被引：3，自引：0，他引：3
了解外来入侵物种（alien invasive species,AIS)的生物学涉及纯生物学及应用生物学的问题,但是靠预先设计的实验来加深人们的了解显然是不可能的,然而我们可以研究现有的入侵,这也是一个很好的途径,本文利用新西兰历史上的一些记录,探讨了物种在新环境中成功定居的因素,令人惊奇的是,物种间的生物学差异对成功的定居几乎没有什么作用,相反,真正起作用的是一个物种被引入新环境的频率及数量。 相似文献
7.
Yehezkel Buba;Moshe Kiflawi;Melodie A. McGeoch;Jonathan Belmaker; 《Global Ecology and Biogeography》2024,33(8):e13859
Reducing the rate of alien species introductions is a major conservation aim. However, accurately quantifying the rate at which species are introduced into new regions remains a challenge due to the confounding effect of observation efforts on discovery records. Despite the recognition of this issue, most analyses are still based on raw discovery records, leading to biased inferences. In this study, we evaluate different models for estimating introduction rates, including new models that use auxiliary data on observation effort, and identify their strengths and weaknesses. 相似文献
8.
Courchamp F Chapuis JL Pascal M 《Biological reviews of the Cambridge Philosophical Society》2003,78(3):347-383
The invasion of ecosystems by exotic species is currently viewed as one of the most important sources of biodiversity loss. The largest part of this loss occurs on islands, where indigenous species have often evolved in the absence of strong competition, herbivory, parasitism or predation. As a result, introduced species thrive in those optimal insular ecosystems affecting their plant food, competitors or animal prey. As islands are characterised by a high rate of endemism, the impacted populations often correspond to local subspecies or even unique species. One of the most important taxa concerning biological invasions on islands is mammals. A small number of mammal species is responsible for most of the damage to invaded insular ecosystems: rats, cats, goats, rabbits, pigs and a few others. The effect of alien invasive species may be simple or very complex, especially since a large array of invasive species, mammals and others, can be present simultaneously and interact among themselves as well as with the indigenous species. In most cases, introduced species generally have a strong impact and they often are responsible for the impoverishment of the local flora and fauna. The best response to these effects is almost always to control the alien population, either by regularly reducing their numbers, or better still, by eradicating the population as a whole from the island. Several types of methods are currently used: physical (trapping, shooting), chemical (poisoning) and biological (e.g. directed use of diseases). Each has its own set of advantages and disadvantages, depending on the mammal species targeted. The best strategy is almost always to combine several methods. Whatever the strategy used, its long-term success is critically dependent on solid support from several different areas, including financial support, staff commitment, and public support, to name only a few. In many cases, the elimination of the alien invasive species is followed by a rapid and often spectacular recovery of the impacted local populations. However, in other cases, the removal of the alien is not sufficient for the damaged ecosystem to revert to its former state, and complementary actions, such as species re-introduction, are required. A third situation may be widespread: the sudden removal of the alien species may generate a further disequilibrium, resulting in further or greater damage to the ecosystem. Given the numerous and complex population interactions among island species, it is difficult to predict the outcome of the removal of key species, such as a top predator. This justifies careful pre-control study and preparation prior to initiating the eradication of an alien species, in order to avoid an ecological catastrophe. In addition, long-term monitoring ofthe post-eradication ecosystem is crucial to assess success and prevent reinvasion. 相似文献
9.
Niche-based modelling as a tool for predicting the risk of alien plant invasions at a global scale 总被引：11，自引：0，他引：11
WILFRIED THUILLER † DAVID M. RICHARDSON‡ PETR PY&#;EK§¶ GUY F. MIDGLEY &#; GREG O. HUGHES MATHIEU ROUGET 《Global Change Biology》2005,11(12):2234-2250
Predicting the probability of successful establishment of plant species by matching climatic variables has considerable potential for incorporation in early warning systems for the management of biological invasions. We select South Africa as a model source area of invasions worldwide because it is an important exporter of plant species to other parts of the world because of the huge international demand for indigenous flora from this biodiversity hotspot. We first mapped the five ecoregions that occur both in South Africa and other parts of the world, but the very coarse definition of the ecoregions led to unreliable results in terms of predicting invasible areas. We then determined the bioclimatic features of South Africa's major terrestrial biomes and projected the potential distribution of analogous areas throughout the world. This approach is much more powerful, but depends strongly on how particular biomes are defined in donor countries. Finally, we developed bioclimatic niche models for 96 plant taxa (species and subspecies) endemic to South Africa and invasive elsewhere, and projected these globally after successfully evaluating model projections specifically for three well‐known invasive species (Carpobrotus edulis, Senecio glastifolius, Vellereophyton dealbatum) in different target areas. Cumulative probabilities of climatic suitability show that high‐risk regions are spatially limited globally but that these closely match hotspots of plant biodiversity. These probabilities are significantly correlated with the number of recorded invasive species from South Africa in natural areas, emphasizing the pivotal role of climate in defining invasion potential. Accounting for potential transfer vectors (trade and tourism) significantly adds to the explanatory power of climate suitability as an index of invasibility. The close match that we found between the climatic component of the ecological habitat suitability and the current pattern of occurrence of South Africa alien species in other parts of the world is encouraging. If species' distribution data in the donor country are available, climatic niche modelling offers a powerful tool for efficient and unbiased first‐step screening. Given that eradication of an established invasive species is extremely difficult and expensive, areas identified as potential new sites should be monitored and quarantine measures should be adopted. 相似文献
10.
Marcel Rejmánek Brian J. Huntley Johannes J. Le Roux David M. Richardson 《African Journal of Ecology》2017,55(1):56-69
Angola is one of the most neglected African countries in terms of botanical research, in respect of both native and naturalized species. We conducted a rapid assessment of invasive plant species in western Angola during August 2014. In thirteen primary vegetation types, we recorded populations of 44 naturalized plant species, nineteen of which are conclusively invasive (spreading far from introduction sites). Dense invasive populations of Chromolaena odorata, Inga vera and Opuntia stricta pose the greatest environmental and economic threats. Some species with known taxonomic and/or biogeographic uncertainties (e.g. Chromolaena odorata and Ageratina adenophora) or which lacked key characteristics for identification such as flowers during our survey (e.g. Eucalyptus spp.) were subjected to DNA barcoding for comparisons with available genetic data from other studies. This approach allowed us to confirm the identity of taxonomically challenging taxa such as Inga vera, Opuntia stricta and Prosopis chilensis, to conclusively differentiate Chromolaena odorata from Ageratina adenophora, and identify the subspecific identity of Acacia saligna. Canonical correspondence analysis was used to assess the presence and abundance of invasive plant species with respect to the major abiotic factors and vegetation types. Three fairly distinct groups of species emerge from this analysis: (i) species of dry lowland habitats (Calotropis gigantea, Leucaena leucocephala and Opuntia stricta); (ii) species of relatively wet habitats at mid elevations (Ageratum conyzoides, Bidens pilosa, Cardiospermum grandiflorum, Chromolaena odorata, Solanum mauritianum and Tithonia diversifolia); and (iii) upland species (Ageratina adenophora, Galinsoga parviflora and Tagetes minuta). Several invasive species that are widespread in other tropical and subtropical African countries are currently either missing (e.g. many Australian Acacia species, Azolla filiculoides, Broussonetia papyrifera, Clidemia hirta, Parthenium hysterophorus, Rubus rosaefolius, Salvinia molesta), have only very localized populations in Angola (e.g. Lantana camara, Prosopis chilensis) or exist only as planted individuals (e.g. Acacia mearnsii and A. saligna subsp. saligna). 相似文献
11.
12.
Alessandro Nota;Sandro Bertolino;Francesco Tiralongo;Alfredo Santovito; 《Global Change Biology》2024,30(6):e17362
The presence of alien species represents a major cause of habitat degradation and biodiversity loss worldwide, constituting a critical environmental challenge of our time. Despite sometimes experiencing reduced propagule pressure, leading to a reduced genetic diversity and an increased chance of inbreeding depression, alien invaders are often able to thrive in the habitats of introduction, giving rise to the so-called “genetic paradox” of biological invasions. The adaptation of alien species to the new habitats is therefore a complex aspect of biological invasions, encompassing genetic, epigenetic, and ecological processes. Albeit numerous studies and reviews investigated the mechanistic foundation of the invaders' success, and aimed to solve the genetic paradox, still remains a crucial oversight regarding the temporal context in which adaptation takes place. Given the profound knowledge and management implications, this neglected aspect of invasion biology should receive more attention when examining invaders' ability to thrive in the habitats of introduction. Here, we discuss the adaptation mechanisms exhibited by alien species with the purpose of highlighting the timing of their occurrence during the invasion process. We analyze each stage of the invasion separately, providing evidence that adaptation mechanisms play a role in all of them. However, these mechanisms vary across the different stages of invasion, and are also influenced by other factors, such as the transport speed, the reproduction type of the invader, and the presence of human interventions. Finally, we provide insights into the implications for management, and identify knowledge gaps, suggesting avenues for future research that can shed light on species adaptability. This, in turn, will contribute to a more comprehensive understanding of biological invasions. 相似文献
13.
随着经济全球化快速发展,外来物种入侵危害日益严重。“十三五”时期,我国针对当前面临的重大外来物种入侵威胁,按照基础前沿、共性关键技术与重大产品研发、典型应用示范研究3个层面,部署了一系列科技项目,取得了一批重大科研成果:阐明了入侵物种的入侵机理和进化机制,以及入侵植物与脆弱生态系统互作的调控机制;建立了潜在农业入侵生物信息分析平台,新发外来入侵物种的风险预测与评估模型,重大外来入侵物种的快速检测识别与监测预警技术,以及综合防控技术体系;围绕豚草、空心莲子草、苹果蠹蛾、番茄潜叶蛾、甜菜孢囊线虫等危害特点,开展全程防控技术应用示范。“十三五”期间,基本实现了潜在入侵物种数据量持续丰富完善,新发/突发入侵物种应急防控技术产品有效储备能力增强,重大入侵物种综合防控技术体系逐步健全的良好格局。面向“十四五”,建议继续支持外来物种入侵防控研究,推动“关口前移、疆域监控、灭除阻截、联控减灾”等核心技术的研发,实现有效防控生物入侵的重大目标。 相似文献
14.
The Global Invasive Species Database, GISD, comprises 27 species of the most significant invasive alien insects in the world (through November, 2005), 6 of which are originally native to China, 11 are established in China, and 10 have a potential invasion threat to China. This paper discusses these species in terms of distribution, harmfulness and dispersal ways, and finds that: (i) Information regarding invasive insects in the GISD remains inadequate. Such harmful invasive species as Opogona sacchari (Bojer), Oracella acuta (Lobdell), and Dendroctonus valens LeConte are not included. (ii) Ten species of invasive insects, particularly Lasius neglectus Van Loon and Linepithema humile (Mayr) which become established in areas near China, have the potential to become established in China. (iii) Special attention should be paid to species from Asia and the Americas because of their greater likelihood of becoming established in China. Finally, some management strategies including legislation, quarantine, early warning, prevention and control are suggested. 相似文献
15.
Elia Lo Parrino;Mattia Falaschi;Raoul Manenti;Gentile Francesco Ficetola; 《Ecography》2023,2023(2):e06432
Species distribution models are often used to predict the potential distributions of invasive species outside their native ranges and rely on the assumption of realized niche conservatism. Analyses observed that freshwater invasive species often show high degrees of niche expansion, suggesting limited reliability of species distribution models. However, observed niche shifts can arise because of both actual niche shifts, determined by biological factors, and apparent shifts, due to methodological issues. We compared metrics of niche dynamics calculated using different sets of variables to identify factors that could influence the rate of niche shifts. We collected presence-only data for 40 freshwater invasive animal species, then measured niche shift dynamics using 14 different combinations of environmental variables. Shifts were assessed measuring niche overlap, expansion and unfilling, and testing for niche conservatism. We then built generalized linear mixed models relating niche shifts to methodological choices and biological features. Our results showed that methodological choices strongly affected all the considered niche dynamics metrics, while the effects of biological features were less prominent. Moreover, different niche dynamic measures sometimes provided contradictory assessments of niche conservatism. Niche analyses are powerful tools to predict areas at risk of invasion, but inappropriate methodological choices can lead to apparent niche shifts, questioning niche model reliability and biological interpretation. The high rate of niche expansion observed in freshwater invasive species highlights the importance of delineating objective criteria to determine the set of variables to be used in niche dynamic assessments. 相似文献
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17.
Andropogon gayanus (gamba grass) is an introduced pasture grass that threatens Australia's tropical savannas by modifying fire regimes and species composition. To understand the establishment requirements of A. gayanus, we undertook a field experiment to determine the effect of canopy cover and ground layer disturbance on seedling emergence and survival. Seed was sown under three canopy treatments (undisturbed, artificial canopy gap, and natural canopy gap) and under three ground layer treatments (Control, Vegetation disturbed, and Soil disturbed). Results have shown that A. gayanus can establish and survive regardless of canopy cover or ground disturbance, although such site disturbances will increase establishment success. Disturbance of both the overstorey canopy and the ground layer increased A. gayanus emergence, whereas seedling survival to 12 mo after seed sowing was affected by ground layer disturbance alone. Disturbance of the canopy increased light transmission, which may have promoted germination. Ground layer disturbance may also have increased light transmission and suitable sites for establishment, and reduced competition for resources, such as water and nutrients. The ability of A. gayanus to spread along disturbed areas, establish in relatively undisturbed savannas, and resprout after fire within 6 mo after seedling emergence suggests that this species will become increasingly widespread in Australia's tropical savannas. Its control is urgently required. 相似文献
18.
Haoxiang Zhao;Xiaoqing Xian;Nianwan Yang;Ting Chen;Jianyu Li;Andy Sheppard;Fanghao Wan;Guojun Qi;Wanxue Liu; 《Global Change Biology》2024,30(11):e17583
Prioritizing potential invasive alien species, introduction pathways, and likely places susceptible to biological invasions is collectively critical for developing the targeting of management strategies at pre-border, border, and post-border. A framework for prioritizing the invasion management that considered all these elements in combination is lacking, particularly in the context of potential coinvasion scenarios of multispecies. Here, for the first time, we have constructed a coupling framework of biological invasions to evaluate and prioritize multiple invasion risks of 35 invasive alien mealybugs (IAMs) that posed a significant threat to the agri-horticultural crops in China. We found that the imported tropical fruits from free trade areas of the Association of Southeast Asian Nations to entry ports of southern China were the primary introduction pathway for IAMs, vectored on various fruit commodities. There was also a high probability for cointroductions of potential multi-IAMs with a single imported tropical fruit. The potential distribution of such IAMs with dissimilar net relatedness were mainly located in southern China. These distributions, however, are likely to expand to the higher latitudes of northern China under future climate and land use/land cover changes. Temperature and anthropogenic factors were both independently and collectively determining factors for the diversity and distribution patterns of imported IAMs under near-current climate conditions. Our findings highlight that these multiple components of global change have and will continue to facilitate the introduction and establishment risks of IAMs in southern China, as well as the spread risk into northern China. Additionally, our findings, for the first time, demonstrated management prioritization across the continuous invasion stages of 35 IAMs in China, and provide additional insights into the development of targeting of their biosecurity and management decisions. 相似文献
19.
Dario Capizzi 《Mammal Review》2020,50(2):124-135
- Impacts of alien invasive species on island communities and ecosystems may be even more detrimental than on the mainland. Therefore, since the 1950s, hundreds of restoration projects have been implemented worldwide, with the aim of controlling or eradicating alien species from islands. To date, no review has been focused on eradication on Mediterranean islands. To fill the gap, I reviewed the available information concerning mammal eradications so far carried out on Mediterranean islands, examining the details of several aspects of project implementation and monitoring.
- I obtained data for 139 attempted eradications on 107 Mediterranean islands in eight countries, with Greece, Italy, and Spain accounting for the highest number. Eradication projects targeted 13 mammal species. The black rat Rattus rattus was the target of over 75% of the known attempted eradications in the Mediterranean Basin; other species targeted were feral goat Capra hircus, house mouse Mus musculus, European rabbit Oryctolagus cuniculus, and domestic cat Felis catus. The most widely adopted technique was poisoning (77% of all eradications), followed by trapping (15%) and hunting (4%). However, techniques were largely target-specific.
- The average failure rate was about 11%. However, this percentage varied according to the specific mammalian order, and eradications of Carnivora failed more often than those of other mammals. Among rodents, house mouse eradication attained a very high failure rate (75%). Reinvasion occurred after 15% of successful eradications.
- A better understanding of the motivations of animal rights activists may improve the chance of success when eradicating charismatic or domesticated species. Furthermore, it is crucial to collect data and case studies about reinvasions, in order to strengthen biosecurity programmes following eradication. As in other parts of the world, the next frontier in alien mammal management on Mediterranean islands concerns the eradication of invasive species from inhabited islands.
20.
Doria R. Gordon Daphne A. Onderdonk Alison M. Fox Randall K. Stocker 《Diversity & distributions》2008,14(2):234-242
The ecological and economic advantages of preventing introduction of species likely to become invasive have increased interest in implementing effective screening tools. We compared the accuracy of the Australian Weed Risk Assessment (WRA) system with that across the six geographies in which it has been tested (New Zealand, Hawaii, Hawaii and Pacific Islands, Czech Republic, Bonin Islands and Florida). Inclusion in four of the tests of a secondary screening tool, developed to reduce the number of species requiring further evaluation, decreased the number of species with that outcome by over 60% on average. Averaging across all tests demonstrated that the WRA system accurately identified major invaders 90%, and non-invaders 70%, of the time. Examined differently, a species of unknown invasive potential is on average likely to be correctly accepted or rejected over 80% of the time for all of these geographies when minor invaders are categorized as invasive. Whereas increasing consistency in definitions and implementation would facilitate understanding of the general application of the WRA system, we believe that this tool functions similarly across islands and continents in tropical and temperate climates and has been sufficiently tested to be adopted as an initial screen for plant species proposed for introduction to a new geography. 相似文献