Range Expansion Of Invasive Species Research Articles

Integrating spatial stream network models and environmentalDNAto estimate current and future distributions of nonnative Smallmouth Bass

AbstractObjectiveClimate change is fueling the rapid range expansion of invasive species in freshwater ecosystems. This has led to mounting calls from natural resource managers for more robust predictions of invasive species distributions to anticipate threats to species of concern and implement proactive conservation and restoration actions. Here, we applied recent advances in fish sampling and statistical modeling in river networks to estimate the current and future watershed‐scale spatial distribution of nonnative Smallmouth BassMicropterus dolomieu.MethodsWe integrated a spatial stream network (SSN) model of stream temperature, landscape environmental covariates, and Smallmouth Bass occurrence data based on environmental DNA (eDNA) detections to develop an SSN species distribution model (SDM) representing current Smallmouth Bass distributions in the Chehalis River, Washington State, a large coastal river basin of ongoing watershed‐scale restoration. The SDM was informed by spatially intensive eDNA sampling from 135 locations in the main stem and major tributaries. We then applied downscaled climate change projections to the SSN SDM to predict Smallmouth Bass range expansion in the basin by late century.ResultWe identified high levels of spatial autocorrelation at hydrological distances of ≤10 km in our eDNA data set, underscoring the importance of applying an SSN modeling framework. Stream temperature was identified as the most important environmental covariate explaining variability in Smallmouth Bass occurrence. Model predictions estimated that current suitable summer habitat for Smallmouth Bass habitat spans 681 km and is projected to nearly double by late century (1333 km) under a moderate climate change scenario. Current and future suitable habitat for Smallmouth Bass is prevalent in important tributaries for spring Chinook SalmonOncorhynchus tshawytscha, a species of major conservation concern in the Chehalis River and more broadly along the Pacific coast. In both the main stem and tributaries, the SSN SDM predictions of the upstream leading edges of Smallmouth Bass closely align with (within 4.8 km) edges identified by spatially intensive eDNA sampling.ConclusionOur study highlights the value of integrating SSN models with rapidly growing eDNA data sets for accurate and precise riverine fish distribution estimation. Our application provides crucial insights for anticipating the impacts of shifting invasive species on Pacific salmon Oncorhynchusspp. in a warming world.

Chronosequence of invasion reveals minimal losses of population genomic diversity, niche expansion, and trait divergence in the polyploid, leafy spurge.

Rapid evolution may play an important role in the range expansion of invasive species and modify forecasts of invasion, which are the backbone of land management strategies. However, losses of genetic variation associated with colonization bottlenecks may constrain trait and niche divergence at leading range edges, thereby impacting management decisions that anticipate future range expansion. The spatial and temporal scales over which adaptation contributes to invasion dynamics remain unresolved. We leveraged detailed records of the ~130-year invasion history of the invasive polyploid plant, leafy spurge (Euphorbia virgata), across ~500 km in Minnesota, U.S.A. We examined the consequences of range expansion for population genomic diversity, niche breadth, and the evolution of germination behavior. Using genotyping-by-sequencing, we found some population structure in the range core, where introduction occurred, but panmixia among all other populations. Range expansion was accompanied by only modest losses in sequence diversity, with small, isolated populations at the leading edge harboring similar levels of diversity to those in the range core. The climatic niche expanded during most of the range expansion, and the niche of the range core was largely non-overlapping with the invasion front. Ecological niche models indicated that mean temperature of the warmest quarter was the strongest determinant of habitat suitability and that populations at the leading edge had the lowest habitat suitability. Guided by these findings, we tested for rapid evolution in germination behavior over the time course of range expansion using a common garden experiment and temperature manipulations. Germination behavior diverged from the early to late phases of the invasion, with populations from later phases having higher dormancy at lower temperatures. Our results suggest that trait evolution may have contributed to niche expansion during invasion and that distribution models, which inform future management planning, may underestimate invasion potential without accounting for evolution.

Environmentally independent selection for hybrids between divergent freshwater stickleback lineages in semi-natural ponds.

Hybridization following secondary contact of genetically divergent populations can influence the range expansion of invasive species, though specific outcomes depend on the environmental dependence of hybrid fitness. Here, using two genetically and ecologically divergent threespine stickleback lineages that differ in their history of freshwater colonization, we estimate fitness variation of parental lineages and hybrids in semi-natural freshwater ponds with contrasting histories of nutrient loading. In our experiment, we found that fish from the older freshwater lineage (Lake Geneva) and hybrids outperformed fish from the younger freshwater lineage (Lake Constance) in terms of both growth and survival, regardless of the environmental context of our ponds. Across all ponds, hybrids exhibited the highest survival. Although wild-caught adult populations differed in their functional and defence morphology, it is unclear which of these traits underlie the fitness differences observed among juveniles in our experiment. Overall, our work suggests that when hybrid fitness is insensitive to environmental conditions, as observed here, introgression may promote population expansion into unoccupied habitats and accelerate invasion success.

Dynamic connectivity analyses to inform management of the invasive American mink and its native competitor, the European mink

Forecasting habitat suitability and connectivity can be central to both controlling range expansion of invasive species and promoting native species conservation, especially under changing climate conditions. This study aimed to identify and prioritize areas in Spain to control the expansion of one of the most harmful invasive species in Europe, the American mink, while conserving its counterpart, the endangered European mink, under current and future conditions. We used ensemble habitat suitability and dynamic connectivity models to predict species ranges and movement routes considering likely climate change under three emission scenarios. Then, using habitat availability metrics, we prioritized areas for invasive mink control and native mink conservation and classified them into different management zones that reflected the overlap between species and threat from American to European minks. Results suggest that both species are likely to experience declines in habitat and connectivity under climate change scenarios with significantly larger declines by the end of the century for European minks (72 and 80% respectively) than for American minks (41 and 32%). Priority areas for management of both species varied over time and across emission scenarios, with a general shift in priority habitat towards the North-East of the study area. Our findings demonstrate how habitat suitability and dynamic connectivity approaches can guide long-term management strategies to control invasive species and conserve native species while accounting for likely landscape changes. The simultaneous study of both invasive and native species can support prioritized management action and inform management planning of the intensity, extent, and techniques of intervention depending on the overlap between species.

Live to Die Another Day: Regeneration in Diopatra aciculata Knox and Cameron, 1971 (Annelida: Onuphidae) Collected as Bait in Knysna Estuary, South Africa

Regeneration is critical for survivorship after injury, sublethal predation, and asexual reproduction; it allows individuals to recover, potentially enabling populations of bait species to overcome the effects of bait collection through incidental asexual reproduction. Opportunities for regeneration are created when worms break during collection (which happens more often than not) and are thrown back into the estuary. Additionally, the trade and movement of bait could result in the range expansion of invasive species. This study investigated bait collection habits of local fishermen and the in situ incidence of regeneration in the estuarine moonshine worm, Diopatra aciculata. The evidence shows that this species is capable of anterior and posterior regeneration. The disproportionately small percentage of worms that seem to be recovering from the degree of damage that may be inflicted during bait collection suggests that regeneration may not help worms to withstand the effects of bait collection. However, the continuous movement and discarding of even small numbers of bait in other estuaries can lead to range expansion through incremental build-up, forming new populations, if these fragments are large enough to regenerate.

Long distance dispersal of monk parakeets

Invasive species threaten biodiversity all around the world and for this reason, identifying the causes and mitigating their effects is a priority in conservation biology. One of the most important factors when dealing with invasive species is dispersal, because the distribution of dispersal distances among members of a population can greatly affect the rate of spread of these invasive populations. Long distance dispersal events have a disproportionately large influence on dispersal kernel estimations, but because of restricted spatial sampling scales they are difficult to detect. Here we use an extensive database of 3,114 monk parakeets ringed in Barcelona city since 2002 as part of an extensive control program across Catalonia where 3,460 birds have been captured since 2013. Our aim was to describe these long–distance movements of monk parakeets. We recorded dispersal distances of over 10 km for a total of eight individuals. Long–distance dispersions were in all directions and both males and females were involved. While some individuals moved in their first year, others delayed dispersal several years. Given that long–distance dispersal events can have a large influence on the rate of range expansion of invasive species this information can be of great utility when modeling the dispersal and spread of the species.

Fitness‐related traits are maximized in recently introduced, slow‐growing populations of a global invasive clam

AbstractMany species are shifting their ranges and being forced to rapidly respond to novel stressful environmental conditions. Colonizing individuals experience strong selective forces that favor the expression of life history traits notably affecting dispersal and reproductive rates in newly invaded habitats. Limited information is currently available on trait variation within the invasive range despite being critical for understanding ecological and evolutionary factors that drive the process of range expansion of invasive species. Here we evaluated life history shifts in the widely introduced Asian clam Corbicula cf. C. fluminea within its invaded range. Through an exhaustive literature search, we obtained data for 17 invasive populations of this clam from different ecosystems worldwide. We tested the relationship between population and individual parameters relevant to the process of range expansion. Our main results are that recently introduced populations of clams were characterized by (a) low density and low rate of population increase, (b) earlier reproduction in slow‐growing populations of clams, and (c) no effect of density on population increase. All populations of the Asian clam analyzed in this study, which are fixed for one genotype (the lineage called Form A/R), experienced different selective environments in the introduced range. These findings support the perspective that adaptive phenotypic plasticity favored the expression of traits that maximize fitness in recently established populations, which faced stronger r‐selective forces relative to long‐established ones. We discuss the role of plasticity in facilitating rapid adaptation and in increasing the likelihood of populations to overcome difficulties associated with low densities and low population increase in newly invaded areas.

Predicting the Current and Future Distribution of the Invasive Weed Ageratina adenophora in the Chitwan–Annapurna Landscape, Nepal

With increasing globalization, trade, and human movement, the rate of alien species introduction has increased all around the globe. In addition, climate change is thought to exacerbate the situation by allowing range expansion of invasive species into new areas. Predicting the distribution of invasive species under conditions of climate change is important for identifying susceptible areas of invasion and developing strategies for limiting their expansion. We used Maxent modeling to predict the distribution of one of the world's most aggressive invasive weeds, Ageratina adenophora (Sprengel) R. King and H. Robinson, in the Chitwan–Annapurna Landscape (CHAL) of Nepal under current conditions and 3 future climate change trajectories based on 3 representative concentration pathways (RCPs 2.6, 4.5, and 8.5) in 2 different time periods (2050 and 2070) using species occurrence data, and bioclimatic and topographic variables. Minimum temperature in the coldest month was the most important variable affecting the distribution of A. adenophora. About 38% (12,215 km2) of the CHAL area is climatically suitable for A. adenophora, with the Middle Mountain physiographic region being the most suitable one. A predicted increase in current suitable areas ranges from 1 to 2% under future climate scenarios (RCP 2.6 and RCP 8.5). All protected areas and 3 physiographic regions (Siwaliks, High Mountain, High Himalaya) are likely to gain climatically suitable areas in future climate scenarios. The upper elevational distribution limit of the weed is expected to expand by 31–48 m in future climate scenarios, suggesting that the weed will colonize additional areas at higher elevations in the future. In conclusion, our results showed that a vast area of CHAL is climatically suitable for A. adenophora. Expected further range expansion and upslope migration in the future make it essential to initiate effective management measures to prevent further negative impacts of this invasive plant.

Predicting range expansion of invasive species: Pitfalls and best practices for obtaining biologically realistic projections

AbstractAimSpecies distribution models (SDMs) are widely used to forecast potential range expansion of invasive species. However, invasive species occurrence datasets often have spatial biases that may violate key SDM assumptions. In this study, we examined alternative methods of spatial bias correction and multiple methods for model evaluation for seven invasive plant species.LocationNorth America.TaxonCommon Tansy (Tanacetum vulgare), Wild Parsnip (Pastinaca sativa), Leafy Spurge (Euphorbia virgata), Common Teasel (Dipsacus fullonum), Brown Knapweed (Centaurea jacea), Black Swallowwort (Vincetoxicum nigrum) and Dalmatian Toadflax (Linaria dalmatica).MethodsWe employed bias‐correction measures for both occurrence sampling and background sampling inputs in a factorial design for Maxent resulting in six potential models for each species. We evaluated our models for complexity, model fit and using commonly employed evaluation metrics: AUC, partial AUC, the continuous Boyce index and sensitivity. We then developed a structured process for model selection.ResultsModels developed without occurrence or background bias correction often were overly complex and did not transfer well to expanding range fronts. Conversely, models that employed occurrence and/or background bias‐correction measures were less complex, had better AICc scores and had greater projection into incipient areas. These simpler models were also more likely to be selected when evaluated using a process that integrated multiple evaluation metrics. We found that invasion history (e.g. established versus incipient) was associated with the effectiveness of spatial bias correction techniques.Main ConclusionsWhile challenges exist in building climate‐based correlative species distribution models for invasive species, we found that methods relying on maximizing AUC performed poorly for invasive species. We advocate for the use of multiple and diverse metrics for model evaluation. Users of species distribution models need to incorporate explicit consideration of model discrimination, model fit and model complexity into their decision‐making processes if they are to build biologically realistic models.

Exploring larval phenology as predictor for range expansion in an invasive species

Predicting range expansion of invasive species is one of the key challenges in ecology. We modelled the phenological window for successful larval release and development (WLR) in order to predict poleward expansion of the invasive crab Hemigrapsus sanguineus along the Atlantic coast of North America and north Europe. WLR quantifies the number of opportunities (in days) when larval release leads to a successful completion of the larval phase; WLR depends on the effects of temperature on the duration of larval development and survival. Successful larval development is a necessary requirement for the establishment of self‐persistent local populations. WLR was computed from a mechanistic model, based on in situ temperature time series and a laboratory–calibrated curve predicting duration of larval development from temperature. As a validation step, we checked that model predictions of the time of larval settlement matched observations from the field for our local population (Helgoland, North Sea). We then applied our model to the North American shores because larvae from our European population showed, in the laboratory, similar responses to temperature to those of a North American population. WLR correctly predicted the northern distribution limit in North American shores, where the poleward expansion of H. sanguineus appear to have stalled (as of 2015). For north Europe, where H. sanguineus is a recent invader, WLR predicted ample room for poleward expansion towards NE England and S Norway. We also explored the importance of year‐to‐year variation in temperature for WLR and potential expansion: variations in WLR highlighted the role of heat waves as likely promoters of recruitment subsidising sink populations located at the distribution limits. Overall, phenological windows may be used as a part of a warning system enabling more targeted programs for monitoring.

Shipwrecks help invasive coral to expand range in the Atlantic Ocean

The invasive coral Tubastraea tagusensis (sun coral) is a habitat-forming species currently increasing its geographical range into the Atlantic Ocean, thereby causing negative ecological and socioeconomic impacts. Scuba divers observed this coral in the western equatorial Atlantic in January 2020, growing at high densities on a shipwreck from World War II (sunk in 1943) at a depth of approximately 32 m. Available footage from the beginning of the decade (2012–2018) shows no obvious signs of sun coral on this shipwreck, suggesting recent colonization and range expansion. The recent evidence of expansion was found 200 km east of the last record, which was also found on a WWII shipwreck (sunk in 1942) in 2016. We have identified hundreds of overlooked WWII shipwrecks, as well as new wrecks in shallow and mesophotic waters, that may provide stepping-stone habitats for this coral to expand its distribution in the Atlantic. We discuss the role of shipwrecks as a network of stepping stones for the sun coral spread, creating complementary paths for the invasiveness by overcoming physiological traits and the short lifespan of the coral larvae. Previous research underestimates the importance of these artificial stepping-stone patches in sustaining crucial dispersal events and range expansion of invasive species. These results are a call to action to manage the invasive Tubastraea corals at a national and international scale in the Atlantic basin.

Theory and practice to conserve freshwater biodiversity in the Anthropocene

Abstract The unprecedented impact of human activities on nature has led scientists to propose we might now be in a new geological epoch: the Anthropocene. Significant human alterations of freshwater systems include massive changes to soil erosion–deposition dynamics, hydrological regimes via impoundment and diversion, land‐use conversion, chemical and nutrient pollution, and human‐assisted range expansion of invasive species. In this human‐dominated epoch, biodiversity, which includes all life on Earth, is at risk, and freshwater biodiversity shows the strongest examples of the extent of this threat. We live in a world where it is necessary to find optimal ways to balance the growing human need for fresh water with ensuring that freshwater ecosystems remain functional in support of the biodiversity that inhabits them and the services these systems provide. Within the broader context of freshwater management in the Anthropocene, this special issue targets freshwater biodiversity and habitat conservation through a variety of lenses. Four main areas of emphasis include: conservation approaches; advances in model and tool development; enhancing water planning; and management and protection of species and habitats. For manuscripts included in this special issue, all authors were instructed to demonstrate how the material presented, be it commentary, conservation prioritization, new methodology or other subject matter, is broadly applicable and transferable.

Niche expansion of the invasive plant species Ageratina adenophora despite evolutionary constraints

AbstractAimEcological inferences drawn from studies on niche dynamics of invasive species are often limited due to difficulties in disentangling evolutionary adaptations of the fundamental niche from demographic and interspecific processes shaping the realized niche. We used Ageratina adenophora, an invasive plant with restricted evolutionary potential to investigate shifts in the realized climatic niche independent of potential evolutionary adaptations.LocationNative Mexican range; exotic ranges in Asia, the USA, the Canary Islands and Australia.TaxonInvasive Asteraceae A. adenophora (Spreng.) R.M.King & H.Rob. Commonly known as Crofton weed.MethodsWe compiled a robust occurrence dataset of A. adenophora for its native Mexican range and four exotic ranges (Asia, USA, Canary Islands, and Australia) and quantified pairwise niche overlap (Schoener's D) and niche dynamic (stable, unfilling and expansion) indices between the native and exotic ranges in reduced climatic space using smoothed occurrence densities. Niche shift was statistically tested using niche equivalency tests.ResultsThe value of niche overlap (Schoener's D) differed considerably, ranging from relatively high between Mexico and Asia to low between Mexico and Australia. The niche dynamic indices indicated highest level of niche stability in Asia while highest degree of unstable niche was detected in Australia due to both niche expansion and unfilling. The niche similarity tests indicated that the native niche is more similar to the exotic niche than any randomly sampled niche from the exotic range. However, the niche equivalency tests showed evidence of niche differentiation as the observed niche overlap was lower than expected by chance for all pairwise comparisons. Jointly these tests indicate that despite the similarity, the native niche is not perfectly identical to any of the exotic niches.Main conclusionsThe current study has direct implications for understanding range expansion of invasive species even in the absence of evolutionary adaptation. Our study indicates that invasive species can occupy different, non‐consistent realized climatic niches in different parts of the world, thus limiting the transferability of species distribution models and corresponding risk assessments or future projections.

Loss of plasticity in life‐history strategy associated with secondary invasion into stressful environments in invasive narrowleaf plantain (Plantago lanceolata L.)

AbstractAdaptation to changing environments is a fundamental process occurring throughout a species’ range, particularly under novel and stressful conditions at the range‐edges of invasive species. However, the evolutionary consequences associated with adaptation are still poorly understood. Secondary invasion into stressful areas may incur fitness costs that could limit range expansion. In addition, developmental plasticity is predicted to be lost under strong selection in stressful habitats. We assessed populations across a range transect of an invasive plant (Plantago lanceolata L.) for a loss of developmental plasticity and for adaptation costs, where there was prior expansion inland into stressful and novel areas from relatively benign areas closer to the coast. In the glasshouse, we grew plants from seed originating from two secondary invasion locations (near‐edge and edge), and from the range centre location representing the area of primary invasion. Plants were exposed to high or low nutrient treatment, and novel copper stress and control (no copper) treatment to assess adaptation costs associated with secondary invasion. In addition, we compared the costs in near‐edge and edge plants. Developmental plasticity in life‐history traits was lost for secondary invasion plants compared to plants from the range centre. Plants from secondary invasion locations expressed a slower life‐history under both nutrient treatments. In contrast, range‐centre plants were able to switch to a faster life‐history under high nutrient treatment. Our copper treatment had only slight effects on plants, where they expressed intermediate specific leaf area (SLA) under copper treatment. Near‐edge plants had the lowest plant size and reproduction. The loss of plasticity associated with secondary invasion may have implications on evolution in range‐edge populations. Phenotypic plasticity may have initially mediated ecological adaptation to stressful habitats; however, adaptation to stressful conditions can also have the consequence of inhibiting further range expansion in invasive species.

Sex‐specific shifts in morphology and colour pattern polymorphism during range expansion of an invasive lizard

AbstractAimHuman‐assisted range expansion of animals to new environments can lead to phenotypic shifts over ecological time‐scales. We investigated whether phenotypic changes are sex‐specific using an invasive lizard (Lampropholis delicata).LocationPacific region (Hawaiian Islands, Lord Howe Island, New Zealand, eastern Australia).MethodsUsing our knowledge of the introduction history of L. delicata, we examined museum specimens of individuals collected across the native and introduced range to determine whether shifts in morphology or colour pattern polymorphism had occurred during its range expansion, and if so, whether they differed between the sexes.ResultsSexual dimorphism in both size and shape was documented within the native range of the delicate skink. However, during range expansion, phenotypic shifts were observed in shape, but not size. In two of the three invasive populations, these phenotypic shifts were sex‐specific. In the Hawaiian Islands, changes in shape were driven by males, whereas in New Zealand it was due to shifts in females. Similarly, changes in the frequency of a colour pattern polymorphism, a mid‐lateral stripe shown to have sex‐specific impacts on fitness (positive in females, negative in males), occurred following colonization of the Hawaiian Islands and Lord Howe Island. In Hawaii, the incidence of the polymorphism increased over time in females, and decreased in males.Main conclusionsPhenotypic shifts during the range expansion of invasive species may be sex‐specific, and are potentially related to the degree of realized niche shift that has occurred between the source and introduced range.

Evidence for the transfer of a soil‐borne contaminant from plants to ants via an aphid mediator

1. Uptake of environmental contaminants by lower trophic groups can have negative effects on higher trophic groups. This study tested the ability of selenium, an environmental contaminant found in high concentrations throughout the tissues of certain accumulating plants, to be transferred to ants via aphid tissue and honeydew.2. Plants of the selenium accumulator, Raphanus sativus (wild radish), were watered with three different selenium treatments (0, 0.25 or 0.5 µg Se ml−1). Aphids, Myzus persicae, and Argentine ant colonies, Linepithema humile, were added to each caged plant and allowed to interact freely. Ant colonies were supplemented with one of three different food options to encourage the consumption of aphids, aphid honeydew, or aphids and honeydew.3. The accumulation of selenium by each trophic group and a trophic transfer factor (TTF) was calculated. The TTF for plants to aphids was > 1, indicating biomagnification, whereas the TTF for aphids to worker ants was < 1, indicating only biotransfer. Accumulated levels by worker ants did not statistically differ as a result of diet.4. The amounts of selenium acquired by ants as a factor of diet and caste were compared. Plants, aphids and worker ants accumulated selenium in a dose‐dependent manner. Ant queens did not contain detectable amounts of selenium. Honeydew contained comparable amounts of selenium to plant selenium levels.5. Access to toxic compounds via honeydew and insect protein may have negative effects on the range expansion of invasive species, such as the Argentine ant.

Effects of long-range taxis and population pressure on the range expansion of invasive species in heterogeneous environments

We consider a new model for biological invasions in periodic patchy environments, in which long-range taxis and population pressure are incorporated in the framework of reaction-diffusion-advection equations. We assume that long-range taxis is induced by a weighted integral of stimuli within a certain sensing range. Population pressure is incorporated in the diffusion coefficient that linearly increases with population density. We first analyze the model in the absence of population pressure and demonstrate how the sensing length of long-range taxis influences the range expansion pattern of invasive species and its rate of spread. The effects of population pressure are examined for both homogeneous and periodic patchy environments. For the homogeneous environment, an exact and explicit traveling wave solution and the spreading speed are obtained. For the periodic patchy environment, we find numerically that a population starting from any localized distribution evolves to a traveling periodic wave if the null solution of the RDA equation is locally unstable, and that the traveling wave speed significantly increases with increasing population pressure. Furthermore, the population pressure and taxis intensity synergistically enhance the spreading speed when they are increased together.

Analysis of the invasiveness of spotted wing Drosophila (Drosophila suzukii) in North America, Europe, and the Mediterranean Basin

The polyphagous Asian vinegar fly Drosophila suzukii (spotted wing Drosophila) is a native of Eastern and Southeastern Asia. It emerged as an important invasive insect pest of berries and stone fruits in the Americas and Europe beginning in 2008. Species distribution models are commonly used for analyzing the extant and potential range expansion of invasive species. Previous modeling efforts for D. suzukii include a degree-day model, a MaxEnt ecological niche model, a demographic model incorporating the effects of temperature, and a preliminary mechanistic physiologically-based demographic model (PBDM). In the present analysis, we refine the PBDM for D. suzukii based on biological data reported in the literature. The PBDM is used to assess the effects of temperature and relative humidity from a recently published global climate dataset (AgMERRA) on the prospective geographic distribution and relative abundance of the pest in the USA and Mexico, and in Europe and the Mediterranean Basin. Our focus is on areas of recent invasion and of predicted higher invasiveness in these areas. Although the species is native to Asia and is of putative temperate origins, it has established in subtropical to north temperate zones worldwide where it infests a wide range of wild and domesticated berries and stone fruits. The model captures the observed phenology of D. suzukii at specific locations, as well as the potential geographic distribution and relative favorability across larger regions. The main limiting factor is cold winter temperature in northern areas, though high temperatures and low relative humidity may be limiting in arid areas. The effect of greater cold tolerance in winter morph adults is explored.

Climate change turns up the heat on vertebrate pest control

Climate change and invasive species threaten global food security and native biodiversity. Individually, they can degrade resources and ecosystem services, and increase management costs. Together, they can produce complex effects, such as facilitating range expansion of invasive species. Climate change may also constrain the ability to manage invasive mammalian species by directly disrupting optimal strategies for control. Invasive species are often most susceptible to anthropogenic control methods when natural food is limiting. We demonstrate quantitatively how a trend towards warmer winters over the past >60 years has significantly reduced the window of time for effective control of an invasive mammalian pest (European rabbit Oryctolagus cuniculus) in temperate New Zealand. The phenomenon described is likely generalizable to the control of other vertebrate pests, particularly in temperate systems where they are seasonally food limited. Climate change may thus exacerbate the unwanted impacts of invasive species by reducing our ability to manage them effectively.

基于个体的空间显性模型和遥感技术模拟入侵植物扩张机制

PDF HTML阅读 XML下载 导出引用 引用提醒 基于个体的空间显性模型和遥感技术模拟入侵植物扩张机制 DOI: 10.5846/stxb201405090918 作者: 作者单位: 南京师范大学地理科学学院,南京师范大学地理科学学院,南京师范大学地理科学学院,南京师范大学地理科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(31470519,31370484,40901094);江苏省自然科学基金项目(BK20131399);江苏省高校优势学科建设工程资助项目 The dispersal mechanism of invasive plants based on a spatially explicit individual-based model and Remote sensing technology: a case study of Spartina alterniflora Author: Affiliation: College of Geography Science,Nanjing Normal University,College of Geography Science,Nanjing Normal University,College of Geography Science,Nanjing Normal University,College of Geography Science,Nanjing Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于个体的空间显性模型和遥感技术,以互花米草为例,模拟了自1997到2010年的种群扩张动态,揭示了土地利用变化与潮间带高程的影响;并通过全局敏感性分析揭示了种子扩散、成体存活率、有性和无性繁殖等种群统计学特征对互花米草种群扩张的相对重要性。研究结果发现:1)有性繁殖与无性繁殖共同决定互花米草种群快速扩张;2)潮间带高程和土地利用变化显著影响模型预测的精度,对互花米草种群扩张有非常重要的影响;3)成体存活率与种子长距离扩散是影响互花米草种群扩张速度最重要的因素;无性繁殖比有性繁殖对种群扩张的影响更大;种子长距离扩散比本地扩散更为重要,同时,小概率的种子长距离扩散事件对种群扩张有非常重要的影响。为了经济有效地控制外来入侵植物的扩张,应该抑制种子的长距离扩散和移除种子长距离扩散形成的位于入侵前沿的小斑块。 Abstract:Biological invasion is a major cause of biodiversity loss, and poses a growing threat to human health. Therefore, it is necessary to reveal the dispersal mechanisms of invasive plants for biological conservation. Spatially explicit individual-based models account for the life history of a target species, in addition to its dispersal ability;thus, abiotic factors, such as landscape heterogeneity and changes, are widely used for simulating population dynamics. Remote sensing (RS) is an important tool for elucidating changing vegetation patterns associated with broad-scale plant invasions. Therefore, by combining spatially explicit individual-based models with RS and GIS (Geographic Information System) information, it is possible to simulate the population expansion of invasive species accurately in realistic landscapes and to understand their invasive mechanisms. However, few spatially explicit, individual-based models have used RS to investigate spatial and temporal land use changes. In this study, a spatially explicit, individual-based model, combined with remote sensing technology, was built to simulate the range expansion of Smooth cordgrass (Spartina alterniflora) in Yancheng Coastal Wetlands, China, from 1999 to 2010, and to reveal how land use and tideland elevation impact range expansion. Furthermore, a global sensitivity analysis was used to identify the relative importance of adult survival rate, seed dispersal, and sexual and asexual reproduction on range expansion. The results show that removing sexual propagation or asexual reproduction greatly reduces the expansion rate. Thus, rapid expansion requires both sexual and asexual reproduction. Land use changes and tideland elevation reduce simulation accuracy, indicating that they have significant impacts on range expansion. In the global sensitivity analysis, adult survival rate and long-distance seed dispersal distance represented the two most important factors influencing S. alterniflora invasion, while seed production, maximum capacity, and the proportion of long-distance dispersal were the three least important factors. Asexual reproduction contributes much more significantly to quick range expansion than sexual reproduction, except for long-distance dispersal. Seeds dispersed long distances contribute more to quick range expansion than local seed dispersal. Moreover, even a few long-distance dispersal events are enough for quick range expansion. Therefore, invasion control strategies should target a single reproduction mode to decrease expansion rates. Here, realistic strategies for controlling and managing invasion are suggested to remove low density, small patches formed by long-distance seed dispersal at the invasion front before the onset of the growing period, and to limit long-distance seed dispersal during the growing period. The integration of these results to control strategies for S. alterniflora and similar invasive species would considerably reduce management costs, while the likelihood of local or complete eradication would increase. In conclusion, spatially explicit individual-based models combined with RS are verified as being very suitable for simulating the range expansion of invasive species in a realistic landscape, and for revealing dispersal mechanisms. 参考文献 相似文献 引证文献