Biological Invasions

Oficialdegui, Francisco J.; Sánchez, Marta I.; Monsalve-Carcaño, Camino; Boyero, Luz; Bosch, Jaime

doi: 10.1007/s10530-019-02041-6pmid: N/A

Emerging infectious diseases are increasingly recognized as a severe threat to wildlife. Chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is considered one of the most important causes for the decline of amphibian populations worldwide. Identifying potential biological reservoirs and characterizing the role they can play in pathogen maintenance is not only important from a scientific point of view, but also relevant from an applied perspective (e.g. disease control strategies), especially when worldwide distributed invasive species are involved. We aimed (1) to analyse the prevalence and infection intensity of Bd in the invasive red swamp crayfish (Procambarus clarkii) across the western Andalusian region in Spain; and (2) to assess whether the presence of crayfish affects the prevalence and infection intensity of Bd in amphibians of Doñana Natural Space (DNS), a localized highly protected area within the Andalusian region. First, we found that infection prevalence in crayfish guts was 1.5% regionally (four out of 267 crayfish were qPCR positive to Bd, all of them belonging to the same Andalusian population); qPCR positives were histologically confirmed by finding zoosporangia of Bd in gastrointestinal walls of the red swamp crayfish. Second, we found a higher prevalence of Bd infection in DNS (19% for crayfish and 28% for amphibians on average), a place with great diversity and abundance of amphibians. Our analyses showed that prevalence of Bd in amphibians was related to the presence of the red swamp crayfish, indicating that this crayfish could be a suitable predictor of Bd infection in co-occurring amphibians. These results suggest that the red swamp crayfish might be a possible reservoir for Bd, representing an additional indirect impact on amphibians, a role that had not been previously recognised in its invasive range.

Carpio, A.; Miguel, R.; Oteros, J.; Hillström, L.; Tortosa, F.

doi: 10.1007/s10530-019-02042-5pmid: N/A

In a context of the growing concern about the impact of biological invasions, our objective is to review the role of those non-native species that have primarily been introduced for angling purposes in at least one European country. We are particularly interested in: (1) the relative role of sport fish species in the context of non-native species introductions; (2) assessing the relative importance of different fish taxa; (3) identifying similarity patterns in the composition of the angling fish species introduced throughout the continent, and (4) assessing the underlying factors that drive their diversity in Europe. According to our results, 23.6% of the freshwater fish introduced into Europe during the last century were released primarily for angling purposes. The species composition differed among countries, with a higher diversity of introduced angling species in larger countries and in those with a greater GDP per capita, along with a lower latitude. This review stresses that angling was a significant pathway for the introduction of invasive fish species into Europe in the last century. Furthermore, some of the introduced angling species had severe environmental impacts on many European regions. However, introductions of non-native angling species are still occurring. Therefore, existing EU regulations need better enforcement as well as to increase public awareness regarding invasive fish. This will help to preserve biodiversity and improve the sustainability of current angling schemes in increasingly managed European freshwater ecosystems. However, non-native fish could make angling sustainable, although not for biodiversity generally.

Loo, Marcela; Lazic, Desanka; Chakraborty, Debojyoti; Hasenauer, Hubert; Schüler, Silvio

doi: 10.1007/s10530-019-02045-2pmid: 31929722

Genetic admixture and plasticity along with propagule pressure, large seed dispersal distances and fast adaptation support successful establishment and spread of introduced species outside their native range. Consequently, introductions may display climatic niche shifts in the introduced range. Douglas-fir, a controversial forest and ornamental conifer represented by two ecologically different and hybridising varieties, was transferred multiple times outside the native range in North America. Here, we compare climatic and genetic patterns of 38 native populations from North America with six old Pseudotsuga menziesii populations with natural regeneration in the introduced range in Central Europe. Following variety and geographic origin assessment of introduced populations, genotypic and climatic data were examined for signatures of inter-varietal gene flow, reduced genetic diversity, presence of fine-scale spatial genetic structure (SGS), dispersal patterns, and climate similarities between native and introduced range. In the introduced range, dominating coastal variety originated from a restricted area in the US, whereas the interior variety, with limited presence in the European sites, displayed wider geographic origin. Variety hybrids with contributing coastal, but not the interior parent were identified. Differences in genetic diversity between both ranges, but also among the parent and their respective offspring populations in Europe were not found. Old populations in general lacked any SGS, whereas natural regeneration revealed different patterns of SGS. Distances of propagule dispersal ranged between 2.5 and 92 m. The climate of the studied European introduced range was most similar to the climate of the coastal variety from the western Cascade range from which the majority of the analysed coastal European Douglas-fir, but not the European interior variety, was assigned to originate. The results we present here shed not only light on dynamics of invasive species in the introduced range in general, but also allow for refinement of climatic niche modeling when using lower than species level.

Carrera-Martínez, Roberto; Aponte-Díaz, Laura; Ruiz-Arocho, Jorge; Lorenzo-Ramos, Alexander; Jenkins, David

doi: 10.1007/s10530-019-02046-1pmid: N/A

Tropical dry forests are threatened by invasive species. In Puerto Rican dry forests, two of these invasive species are the Harrisia cactus mealybug Hypogeococcus sp. (HCM), a member of the H. pungens-complex (Hemiptera: Pseudococcidae), and the liana Jasminum fluminense (Oleaceae). Here, we aim to determine the effects of HCM and J. fluminense on the flower and fruit production of Pilosocereus royenii and on the short-term mortality of the native columnar (P. royenii and Stenocereus fimbriatus), semi-epiphytic (Selenicereus trigonus and Leptocereus quadricostatus), and globular (Melocactus intortus) cacti of Puerto Rico. To assess HCM infestation, we created a numerical infestation index with six categories, ranging from uninfested and healthy, to heavily infested cacti (0–5) based on the number and size of tumors. Flower and fruit production of P. royenii was observed at three sites, while the survival of all cactus species was observed at twelve sites for 2 years. Mortality of all cacti species increased with severe HCM infestation. Mortality was highest in M. intortus, and lowest in St. fimbriatus and L. quadricostatus. Mortality of P. royenii was negatively correlated to precipitation, and positively to HCM and liana infestation. Individuals of P. royenii that were heavily infested with both HCM and lianas were more likely to die than healthy cacti only infested with lianas, while P. royenii flower and fruit production was negatively correlated only with HCM infestation. This suggests that J. fluminense becomes a better competitor during dry periods when P. royenii is infested with HCM. While other members of the H. pungens-complex are considered biocontrol agents in places where columnar cacti are not native, this study demonstrates that HCM species found in Puerto Rican dry forests could potentially decrease the biodiversity of these cacti in their native habitats.

Bajwa, Ali; Farooq, Muhammad; Nawaz, Ahmad; Yadav, Lava; Chauhan, Bhagirath; Adkins, Steve

doi: 10.1007/s10530-019-02047-0pmid: N/A

Invasive plant species often have negative impacts on agriculture and society in addition to their detrimental effects on biodiversity and environment. It is important to assess such impacts to devise effective management plans. A field survey study was carried out to assess the socio-economic effects of a highly invasive plant species, parthenium weed (Parthenium hysterophorus L.) across the three different cropping regions in Punjab province of Pakistan. The farming communities of different cropping regions reported significant effects of parthenium weed on their crop and livestock production, health and social well-being. The mixed cropping region was heavily infested and most affected region, whereas the cotton–wheat region was least affected. Farmers were well-aware of parthenium weed presence, its biology, habitat, and mode of dispersal across the landscape. All the major crops cultivated were infested by varying degrees of weed densities with potato, sugarcane and maize being the most infested crops. Farmers were generally good at managing the weed in crops which cost them significant amounts of money (ca. $205 per household). Parthenium weed also infested the fodder collection and grazing sites affecting the livestock production negatively. Each farmer lost an additional ca. $935 annually due to the weed infestations on fodder collection sites. A significant proportion of farmers also reported negative effects of the weed on animal health (22–36%) and human health (14–24%). The average annual costs associated with animal health and human health were ca. $2031 and $73 per household, respectively. Despite acknowledging the value of weed management in non-cropped areas, fewer farmers managed it practically in such areas. Most farmers reported parthenium weed as a very difficult-to-manage weed. About 37% of farmers were willing while 60% were likely to participate in a potential management program in future. A comprehensive management strategy is urgently needed to address the looming crisis of parthenium weed invasion across the province and similar approach must be implemented at the national and international level.

Mori, Emiliano; Ferretti, F.; Fattorini, N.

doi: 10.1007/s10530-019-02048-zpmid: N/A

Interspecific interactions shape the structure of animal communities, and they rely on a number of multifactorial mechanisms, including e.g. activity rhythms, ectoparasite prevalence, predation pressure and food habits. Despite this, no study has analysed multispecies interactions by combining such a high number of aspects, mostly because the experimental manipulation of studied populations is rarely possible. In our work, we assessed several aspects of interspecific interactions in a rodent assembly composed by three species, by examining diet and temporal- niche partitioning, as well as relevant ectoparasite load and predation pressure, in a natural environment. We analysed stomach contents and ectoparasite load of 78 individuals belonging to all the species, whereas activity rhythms were measured with camera trapping (2200 night-traps, throughout 1 year). Our findings showed that the largest-sized species, i.e. the brown rat Rattus norvegicus was the strongest competitor and may affect diet, temporal behaviour and susceptibility to parasites of smaller-sized ones, i.e. the black rat Rattus rattus and the house mouse Mus domesticus. Larger-sized species showed a broader trophic niche with respect to smaller-sized ones, whereas the smallest species seemed to avoid the largest ones by shifting its temporal activity when the latter was mostly inactive. Larger-sized species may also act as potential predators towards smaller ones, which are also more vulnerable to ectoparasite infestation and to the predation by the only raptor bird present in the study area, the barn owl Tyto alba. We therefore highlight the importance to carry out community-wide studies, to understand interspecific intraguild relationships.

Navarro-Barranco, C.; Muñoz-Gómez, B.; Saiz, D.; Ros, M.; Guerra-García, J.; Altamirano, M.; Ostalé-Valriberas, E.; Moreira, J.

doi: 10.1007/s10530-019-02049-ypmid: N/A

The addition or loss of habitat-forming species may lead to significant changes in the structure and functioning of marine benthic ecosystems as a whole. However, the nature of the impact of invasive macroalgae on native mobile invertebrate assemblage is still hard to predict. In this sense, the degree of morphological resemblance (mainly structural complexity) between native and exotic habitat-forming species has been proposed as a suitable predictor of epifauna response to biological invasions. The recently introduced macroalga Rugulopteryx okamurae is becoming a dominant element in coastal rocky bottoms in the Strait of Gibraltar, where it is sympatric with the native species Dictyota dichotoma. Despite the high morphological similarity between both habitat-forming species, native and exotic macroalgae hosted different macrofaunal assemblages. Dictyota dichotoma showed lower number of species, abundance of individuals, and diversity values than the introduced macroalga. Most shared species showed higher abundance on R. okamurae, but there was high variability in the response to macroalgal identity across higher taxa. Thus, there were no major differences in polychaete assemblage between macroalgal species or among sites, when considering univariate measures (abundance of individuals, number of species and H′ values) or species composition (with the exception of abundance values), while peracarid crustaceans and molluscs showed the opposite pattern. Therefore, our results suggest that morphological similarities among habitat-forming species do not always allow predicting of whether the invasive taxa are functionally equivalent to native ones. They also highlight the relevance of fine taxonomical resolution for revealing complex impacts of invasive macroalgae. In addition, R. okamurae’s capacity to determine significant changes on native fauna has been pointed out.

Albuquerque, Fábio; Macías-Rodríguez, Miguel; Búrquez, Alberto; Astudillo-Scalia, Yaiyr

doi: 10.1007/s10530-019-02050-5pmid: N/A

In the last decades, more than six hundred exotic species have become established throughout the region of the southwestern United States and northwestern Mexico, including the African buffelgrass (Cenchrus ciliaris L.). Buffelgrass often causes negative impacts on natural ecosystems and it is considered a highly invasive species in many parts of the world. We used 18,550 records from 260 datasets and species distribution modeling (SDM) to provide support for the climatically based and topographic hypotheses, which claim that current climate and topography affect species distribution patterns of plants. We also investigated (1) the geographical distribution of habitat suitability across biotic communities of the Southwest United States and northern Mexico, (2) the association between habitat suitability, climate variables and topography, and (3) the potential effects of climate change on the future distribution of buffelgrass. We found that the geographic pattern of suitability in the southwest generally increases west- and southward, with some high suitability areas also occurring in southern areas of Arizona, USA, and across the state of Sonora, Mexico. We observed that mean temperature and annual precipitation explain spatial variation in suitability better than other climatic and non-climatic variables. Climate change models indicated significant opportunities for contraction across the buffelgrass’ range and fewer for range expansion. In all scenarios, SDMs predicted a high contraction of suitable habitat. Most of these contractions would occur in portions of the Sonoran Desert and the foothills of the Sierra Madre Occidental. We show, for the first time, the potential changes in buffelgrass habitat suitability across major biomes of the Southwest region, under future climate change scenarios.

Japelj, Anže; Kus Veenvliet, Jana; Malovrh, Judita; Verlič, Andrej; Groot, Maarten

doi: 10.1007/s10530-019-02052-3pmid: N/A

Invasive alien species (IAS) require management to mitigate their impact on ecosystems. The success of management decisions often depends on whether they are socially acceptable and to what extent people are willing to be actively involved in an early warning and rapid response system (EWRR). We administered a nation-wide public poll to assess people’s knowledge on plant, insect and fungal IAS; their perception of IAS as an environmental problem; and their support for different IAS management measures. Most respondents (76%) knew the term IAS, and more than half (62%) provided a correct definition. Species with more media attention and those that are easily visible are more frequently identified correctly. Almost all respondents (97%) support an EWRR system; however, there is heterogeneity in terms of the types of actions people approve of. Non-lethal measures garner more support than lethal ones. Gender and previous knowledge also affect the level of agreement. The willingness-to-pay question largely confirmed this, as people were divided into four classes according to their preferences for either biological, mechanical or chemical measures to control IAS; completeness and location of removal; and having an EWRR established. Mechanical removal is the most preferred treatment in two of the four classes, and complete removal is preferred over partial removal in one of the four classes. Having an EWRR is consistently supported in all classes, and removal in urban areas is preferred over removal in forestland in only one class.

Andersen, Jeremy; Havill, Nathan; Broadley, Hannah; Boettner, George; Caccone, Adalgisa; Elkinton, Joseph

doi: 10.1007/s10530-019-02054-1pmid: N/A

In North America the invasive winter moth (Operopthera brumata) has caused defoliation in forest and fruit crop systems in British Columbia, Nova Scotia, Oregon, and in the northeastern United States (the “Northeast”). In the Northeast, it was previously shown that hybridization is occurring with a native congener, Bruce spanworm (O. bruceata)—a species that has a broad distribution across much of North America. Whether hybridization among winter moth and Bruce spanworm populations has occurred in all of regions where winter moth established is unknown. One factor that might influence hybridization between these two species is the presence of reproductive manipulating endosymbionts, such a Wolbachia. To determine the geographic extent of hybridization among populations of these two species, we classified 1400 field-collected moths from Europe and North America as either being winter moth, Bruce spanworm, or hybrids using 10–12 polymorphic microsatellite loci. We then screened each individual for the presence of Wolbachia by PCR amplification of the wsp gene fragment. For all hybrids, we determined their maternal species-lineage by PCR amplification and sequencing of the mitochondrial locus cytochrome oxidase I. We find that winter moth x Bruce spanworm hybrid individuals appear to be present in all regions of North America that winter moth has invaded, and that hybrids are of both winter moth and Bruce spanworm maternal-origins. In addition, we find Wolbachia infected individuals from all species in North America, and that winter moth individuals in North America have a much lower infection rate (11.5%) than individuals in Europe (55.1%).