Predicting invasions in Australia by a Neotropical shrub under climate change: the challenge of novel climates and parameter estimation

Aim  To test how well species distributions and abundance can be predicted following invasion and climate change when using only species distribution and abundance data to estimate parameters.
Location  Models were developed for the species' native range in the Americas and applied to Australia.
Methods  We developed a predictive model for an invasive neotropical shrub ( Parkinsonia aculeata) using a popular ecophysiological bioclimatic modelling technique (CLIMEX) fitted against distribution and abundance data in the Americas. The effect of uncertainty in model parameter estimates on predictions in Australia was tested. Alternative data sources were used when model predictions were sensitive to uncertainty in parameter estimates. The resulting best-fit model was run under two climate change scenarios.
Results  Of the 19 parameters used, 9 could not be fitted using data from the native range. However, only parameters that lowered temperature or increased moisture requirements for growth noticeably altered the model prediction in Australia. Differences in predictions were dramatic, and reflect climates in Australia that were not represented in the Americas (novel climates). However, these poorly fitted parameters could be fitted post hoc using alternative data sources prior to predicting responses to climate change.
Conclusions  Novel climates prevented the development of a predictive model which relied only on native-range distribution and abundance data because certain parameters could not be fitted. In fact, predictions were more sensitive to parameter uncertainty than to climate change scenarios. Where uncertainty in parameter estimates affected predictions, it could be addressed through the inclusion of alternative data sources. However, this may not always be possible, for example in the absence of post-invasion data.     

Climatic analysis to determine where to collect and release Puccinia jaceae var. solstitialis for biological control of yellow starthistle

Puccinia jaceae var. solstitialis is an autoecious rust fungus that is native to areas of Afro-Eurasia with a Mediterranean climate. An isolate collected near Sivas, Turkey was released for classical biological control of yellow starthistle (YST), which is an invasive alien weed in California, USA. The fungus has been released throughout California, but long-term establishment rates are generally low, apparently because this ecotype is not well adapted to the climate where the weed is most invasive. Using a site with excellent establishment as a target, the Match Climates function in CLIMEX climate modeling software identified similar sites in and around the San Francisco Bay Area, east to the Central Valley and Sierra foothills, and along the coast of Southern California. Similar sites in other states include Walla Walla, Washington, Pendelton, Oregon and Salt Lake City, Utah. A Compare Locations model based primarily on experimentally measured temperature and humidity requirements of the rust produced similar results. Using Sacramento, California, which is in the center of YST distribution, as a target, the Match Climates function predicted that the best locations to search for rust accessions to use in California are near Tunis, Tunisia, Foggia, Italy, Khalkis, Greece, Kayseri, Turkey, and possibly Constantine, Algeria. This generally agrees with the prediction of a Compare Locations model based on the geographic distribution of YST in California. Climatic factors that limit the long-term establishment of the fungus are likely to be summer heat and/or dry stress and short dew periods.     

Potential exposure of a classical biological control agent of the soybean aphid, Aphis glycines, on non-target aphids in North America

In summer 2007, the Asian parasitoid Binodoxys communis (Hymenoptera: Braconidae) was released in North America for control of the exotic soybean aphid, Aphis glycines (Hemiptera: Aphididae). Despite its comparatively narrow host range, releases of B. communis may still constitute a risk to native aphid species. To estimate the risk of exposure of non-target aphids to B. communis, we merged assessments of temporal co-occurrence with projections of spatial overlap between B. communis and three native aphid species, and in-field measurements of the incidence of ecological filters that may protect these aphids from parasitism. Temporal co-occurrence was assessed between A. glycines and native aphids (Aphis asclepiadis, Aphis oestlundi, and Aphis monardae) at four different locations in Minnesota, USA. The degree of temporal overlap depended greatly on location and aphid species, ranging between 0 and 100%. All of the native aphids were tended by multiple species of ants, with overall ant-attendance ranging from 26.1 to 89.6%. During temporal overlap with A. glycines, 53 ± 11% of A. monardae colonies were partly found in flower heads of their host plant, with flowers acting as a physical refuge for this aphid. The extent of geographic overlap between B. communis and native aphids based upon Climex modeling was 17–28% for A. monardae, 13–22% for A. oestlundi, 46–55% for A. asclepiadis and 12–24% for the A. asclepiadis species complex. The estimated overall probability of potential exposure of B. communis on native aphids was relatively low (P = 0.115) for A. oestlundi and high (P = 0.550) for A. asclepiades. Physical and ant-mediated refuges considerably lowered probability of population-level impact on A. monardae, and could lead to substantial reduction of exposure for the other native aphids. These findings are used to make broader statements regarding the ecological safety of current B. communis releases and their potential impact on native aphid species in North America.     

Climatic requirements of the eastern paralysis tick,Ixodes holocyclus,with a consideration of its possible geographic range up to 2090

The eastern paralysis tick, Ixodes holocyclus, is an ectoparasite of medical and veterinary importance in Australia. The feeding of I. holocyclus is associated with an ascending flaccid paralysis which kills many dogs and cats each year, with the development of mammalian meat allergy in some humans, and with the transmission of Rickettsia australis (Australian scrub typhus) to humans. Although I. holocyclus has been well studied, it is still not known exactly why this tick cannot establish outside of its present geographic distribution. Here, we aim to account for the presence as well as the absence of I. holocyclus in regions of Australia. We modelled the climatic requirements of I. holocyclus with two methods, CLIMEX, and a new envelope-model approach which we name the ‘climatic-range method’. These methods allowed us to account for 93% and 96% of the geographic distribution of I. holocyclus, respectively. Our analyses indicated that the geographic range of I. holocyclus may not only shift south towards Melbourne, but may also expand in the future, depending on which climate-change scenario comes to pass.     

气候变暖背景下新疆和中哈边境亚洲飞蝗适生区预测及变化

亚洲飞蝗Locusta migratoria migratoria是中国新疆与哈萨克斯坦边境区域重要害虫之一,具迁飞性且繁殖能力强,对农牧业经济造成巨大伤害。本文以亚洲飞蝗为研究对象,根据其发生区和相关生物学特性,利用CLIMEX 4.0.2和ArcGIS 10.2相结合,预测其在新疆和中哈边境区域亚洲飞蝗的潜在地理分布。亚洲飞蝗的适生区在新疆境内集中分布在北疆（42.69~48.29°N）,包括伊犁、博尔塔拉中部、塔城西北部及南部、阿勒泰西部、昌吉和乌鲁木齐南部地区;哈萨克斯坦境内主要分布在北纬47.03~51.65°N区域,包括东哈萨克斯坦州北部、阿拉木图州东南部境内的湖泊及河流沿岸地区,这与亚洲飞蝗的现有分布点和历史发生记录吻合。未来气候变暖情景下,亚洲飞蝗在中哈边境新疆境内的适生区逐渐扩大,其中在阿勒泰、伊犁、昌吉及乌鲁木齐的高度适生区面积增加,哈密开始出现高度适生区;在哈萨克斯坦边境区域的适生区略有增加,其中东哈萨克斯坦州地区高度适生区面积减少明显。研究结果对区域内亚洲飞蝗的预测预报和综合防控具有重要意义。     

Climate change scenarios and models yield conflicting predictions about the future risk of an invasive species in North America

• 1 The pea leafminer Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) is an invasive species in North America and a serious economic pest on a wide variety of crops. We developed a bioclimatic envelope model (BEM) for this species and examined the envelope's potential location in North America under various future climates.
• 2 We compared the future bioclimatic envelopes for L. huidobrensis using either simple scenarios comprising uniform changes in temperature/precipitation or climate projections from general circulation models (GCMs). Our simple scenarios were: (i) an increase of 0.1°C per degree in latitude with a 20% increase in summer precipitation and a 20% decrease in winter precipitation and (ii) an overall increase of 3°C everywhere, also with the same changes in precipitation. For GCM‐modelled climate change, we used the Canadian Centre for Climate Modelling and Analysis GCM (CGCM2) and the Hadley Centre climate model (HadCM3), each in combination with two scenarios from the Special Report on Emissions Scenarios (A2 and B2).
• 3 The BEM results using the simple scenarios were more similar to each other than to the results obtained using GCM projections. The results were also qualitatively different (i.e. spatially different and divergent) depending on which GCM‐scenario combination was used.
• 4 This modelling exercise illustrates that: (i) results using first approximation simple climate change scenarios can give predictions very different from those that use GCM‐modelled climate projections (comprising a result that has worrying implications for empirical impact research) and that (ii) different GCM‐models using the same scenario can give very different results (implying strong model dependency in projected biological impacts).

     

Rearing and release of Homichloda barkeri (Jacoby) (Coleoptera: Chrysomelidae: Alticinae) for the biological control of prickly acacia, Acacia nilotica ssp. indica (Mimosaceae) in Australia

Abstract Prickly acacia, Acacia nilotica ssp. indica , a major weed of the Mitchell Grass Downs of northern Queensland, has been the target of biological control projects since the 1980s. The striped leaf-feeding beetle, Homichloda barkeri (Coleoptera: Chrysomelidae: Alticinae), was the third insect approved for release for the control of this weed in Australia. However, mass rearing this insect under glasshouse conditions proved to be difficult and time consuming as there were problems associated with low egg-hatching rates and poor larval survival. Eggs in diapause were stimulated to hatch by repeated wetting and drying. Larvae were fed on potted prickly acacia plants in cages. Late-instar larvae were collected and transferred to a mix of sand, peat moss and vermiculite for pupation and adult emergence. Over 10 500 adults were released at 28 sites in north Queensland between November 1996 and December 1999. Initial releases of insects confined to gauze cages resulted in limited adult survival, oviposition and development of first-generation larvae. First-generation larvae were observed at two sites where cages were not used. However, later inspections of release sites, including those made in April and December 2000, April 2001 and late March 2002, failed to find any trace of the insect, which is assumed to have failed to establish. Possible reasons for this failure are discussed.     

Effect of climate change on the potential distribution of the common cutworm (Spodoptera litura) in South Korea

Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), known as common cutworm, is a worldwide pest that causes severe damage to various crops and vegetables in South Korea. In this study, we predicted the potential distribution of S. litura in South Korea in a climate change scenario by applying species distribution modeling. We used the CLIMEX software as a main tool and determined optimal parameter values to simulate the current distribution of S. litura in Asia. We then used these parameter values to predict the species' future distribution in South Korea. As a result, we prepared maps indicating areas with suitable climate for S. litura and showed that these areas gradually increased as a result of climate change. Approximately 98% of the areas in South Korea were predicted to have a favorable climate for S. litura in 2100; 63.2% of the area in South Korea is currently favorable. To the best of our knowledge, this is the first study to predict the potential distribution of S. litura in South Korea, and it provides the basic data necessary to establish an optimal control strategy of this species.     

Evaluating the invasion risk of longhorn crazy ants (Paratrechina longicornis) in South Korea using spatial distribution model

The longhorn crazy ant (Paratrechina longicornis) is a globally distributed ant species with a high invasion risk, suggesting the need to use species distribution modeling to evaluate its potential distribution. Therefore, this study aimed to predict the potential distribution of longhorn crazy ants in response to climate change by using CLIMEX and Maxent and identifying the climatic factors that influence their habitat. Then, the model outcomes were used to construct an ensemble map to evaluate invasion risk in South Korea. The results indicated that temperature-related variables mainly affect the distribution of the longhorn crazy ant, and the two models showed consensus regions in South America, Africa, Australia, and Southeast Asia. Due to climate change, it was expected that the northern limit would somewhat rise. In South Korea, high-risk areas were predicted to be located along the coasts, but they would expand as a consequence of climate change. Since the invasion of longhorn crazy ants has occurred via commercial trades, a relatively high risk in coastal areas demands a high level of attention. We expect that this study will provide initial insight into selecting areas for longhorn crazy ant quarantine with ensemble species distribution modeling.     

落叶松大小蠧在中国适生性分析

运用CLIMEX软件和ArcGIS软件,对落叶松大小蠹Dendroctonus simplex Leconte在中国的适生区进行了预测.结果表明:落叶松大小蠹在我国有很高的适生性,适生范围涉及30个省、市、区,其中黑龙江、吉林、内蒙古、新疆东部、西藏中部和青海为高度适生区.