Killing Carp (Cyprinus carpio) as a Volunteer Practice: implications for community involvement in invasive species management and policy

Community engagement is understood to be one of the keys to successful environmental programs—‘the social pillar’ of management. In this paper we examine community engagement where volunteers participate by killing invasive animals. Most research to date focuses on the biological or management implications of volunteer efforts for the invasive species, with little attention to the people involved or the social acceptability of killing animals in this context. Here, we report on a survey and participant observations of community fishing events in south-eastern Australia, where volunteers fish for and kill carp (Cyprinus carpio). We examine who takes part in these events, their motivations for being involved and the implications for ongoing community engagement. Survey respondents were predominantly well-educated Australian-born men, motivated to fish by a desire to spend time in nature. However, we also noted a strong response from overseas-born men with different motivations. Our survey elicited complex responses regarding killing, illustrating contradictory, sometimes conflicted experiences, which jar with personal motivations. The implications are that questions of ethics must extend to the human volunteers, and that more direct communication of program outcomes and the proposed benefits for volunteers be more rigorously assessed. We argue that invasive species management must contend with the experiences of volunteers, otherwise meaningful dialogue and program objectives risk being undermined.     

Potential distributional changes of invasive crop pest species associated with global climate change

This study investigated the potential global distributional shifts of poikilothermic invasive crop pest species associated with climate change, aiming to understand if their overall global distributions will expand or contract, and how the species distributions will vary across different regions. An ecological niche modelling analysis was conducted for 76 species. The potential distributional changes of the species in 2050 and 2070 were scrutinized for two climate change scenarios, which were further examined across different temperature and precipitation ranges. Results showed that averages of the mean probabilities of presence of the 76 crop pest species were predicted to increase. Higher species turnovers were predicted mostly to occur in areas with increasing predicted species richness. Lower species turnovers, however, were predicted mostly to occur in areas with decreasing predicted species richness. Species richness increases were predicted to occur more often in currently lower temperature (annual mean temperature approximately < 21 °C) or lower precipitation (annual precipitation approximately < 1100 mm) regions. Areas with the current annual mean temperatures at around 27 °C and 7.5 °C, respectively, were predicted to experience the highest decrease and increase in species richness as the climate warms. In conclusion, climate change is likely to expand the pest species’ overall distribution across the globe. It could have more profound impacts on the species distributions of those regions where species richness increases are expected, by altering the species’ community compositions.     

Reproductive characteristics of invasive gammarids in the Rhine-Main-Danube catchment, South Germany

The gammarid composition at 25 sites in the rivers Danube, Main and the southern reaches of the Rhine were studied during the years 2002–2004. Dikerogammarus villosus and Echinogammarus ischnus were the most frequent species prevailing at 17 sites. Sympatric occurrence of D. villosus and E. ischnus was observed at 12 sites. Dikerogammarus haemobaphes was recorded at 7 sites; this species prevailed in the Danube, west of the Weltenburger Enge and in the Isar mouth where it co-existed with native species (Gammarus pulex and/or G. roeseli) at 6 sites. Dikerogammarus bispinosus and E. berilloni were found at only 1 site, where they co-existed with D. villosus and E. ischnus, and with D. villosus and native species, respectively. Investigation of reproductive characteristics at 3 sites showed that females of D. villosus and D. haemobaphes produced the biggest clutches with more than 100 eggs. Females of E. ischnus produced much smaller clutches (10–35 eggs on an average), but very big eggs. Clutch sizes and egg volumes of D. bispinosus and E. berilloni resembled those of native species. Our results suggest that the most successful invaders (D. villosus, D. haemobaphes and E. ischnus) display reproductive traits that facilitate their success. Both Dikerogammarus sp. allocate energy into production of many but small eggs, thus maximizing offspring number, while E. ischnus allocates its energy into production of fewer but large eggs which could be beneficial at sites where food is scarce.     

Application of indigenous benthic amphipods as sediment toxicity testing organisms

A series of experiments were conducted to develop standard test organisms and test protocols for measuring sediment toxicity using candidate amphipods such asMandibulophoxus mai, Monocorophium acherusicum, Haustorioides indivisus, andHaustorioides koreanus, which are indigenous to Korea. The relevant association of test species with sediment substrates was one of the important factors in sediment bioassay. The indigenous amphipodsM. mai andM. acherusicum were well associated with test sediments when they were exposed to various sediment substrates from sand to mud. The tolerant limits to various physico-chemical factors affecting bioassay results such as temperature, salinity and ammonia, as well as sensitivities to reference toxicant and contaminated sediments, were investigated usingM. mai andM. acherusicum in the present study. These amphipods were tolerant to relatively wide ranges of salinity (10~30 psu) and ammonia (<50 ppm), and displayed relevant sensitivity to temperature as well. They are more sensitive to Cd, the reference toxicant, when compared to the standard test species used in other countries. Field-sediment toxicity tests revealed thatM. mai would be more sensitive to sediment-associated pollutants thanM. acherusicum, while the sensitivity ofM. acherusicum was comparable to that ofLeptocheirus plumulosus, which has been used as a standard test species in the United States of America. Overall results of this first attempt to develop an amphipod sediment toxicity test protocol in Korea indicated thatM. mai andM. acherusicum would be applicable in the toxicity assessment of contaminated sediments, following the further evaluation encompassing various ecological and toxicological studies in addition to test method standardization.     

Is exotic plant invasion enhanced by a traditional wildlife habitat management technique?

Soil disturbance is a wildlife habitat management tool that retards succession and promotes early seral vegetation. Our objective was to determine responses of two invasive herbaceous species (Pennisetum ciliare and Salsola iberica) and native perennial grasses to disking on different soils. Two 10 ×40 m plots were delineated within each of 4 blocks on Ramadero loams and 4 blocks on Delmita fine sandy loams. On Delmita soils, canopy cover of P. ciliare, S. iberica, and native perennial grasses averaged across all years was not affected by disking (ANOVA, P>0.05). On Ramadero soils, P. ciliare canopy cover was similar (Tukey's, P>0.05) on control and disked plots for the first 4 years post-disturbance, but P. ciliare cover was 10-fold greater (Tukey's, P=0.02) the 5th year after disking on disked versus control plots. On Ramadero soils, S. iberica canopy cover averaged across all years was 221 times greater (ANOVA, P=0.05) on disked plots than on control plots. Disking did not affect native perennial grass canopy cover. Land managers should consider soil series when disking for wildlife management, as disking disturbance may exacerbate exotic plant ingress and establishment on certain soils.     

Habitat suitability of the invasive water hyacinth and its relation to water quality and macroinvertebrate diversity in a tropical reservoir

In this study, we assessed the relationship between the occurrence of the invasive water hyacinth (Eichhornia crassipes) and water quality properties as well as macroinvertebrate diversity in a tropical reservoir, situated in western Ecuador. Macroinvertebrates and physico-chemical water quality variables were sampled at 32 locations (during the dry season of 2013) in both sites covered and non-covered by water hyacinth in the Daule-Peripa reservoir. The results indicated that, in terms of water quality, only turbidity was significantly different between sampling sites with and without water hyacinth (Mann–Whitney U-test, p < 0.01). The habitat suitability model showed that water hyacinth was present at sites with a low turbidity. The percentage water hyacinth cover increased with decreasing turbidity. The Biological Monitoring Working Party-Colombia score and the Margalef diversity index were significantly higher (Mann–Whitney U-test, p < 0.01) at sampling sites where water hyacinth was present compared to water hyacinth absent sites. However, there were no significant differences in the Shannon–Wiener index, Evenness index and Simpson index between the sampling sites with and without water hyacinth. Our results suggest that water hyacinth cover was an important variable affecting the diversity of macroinvertebrates in the Daule-Peripa reservoir, with intermediate levels of water hyacinth cover having a positive effect on the diversity of macroinvertebrates. Information on the habitat suitability of water hyacinth and its effect on the physico-chemical water quality and the macroinvertebrate community are essential to develop conservation and management programs for large tropical reservoirs such as the Daule-Peripa reservoir and the Guayas river basin, where water resources are being at high risk due to expansion of agricultural and industrial development activities.     

The red swamp crayfish Procambarus clarkii in Europe: Impacts on aquatic ecosystems and human well-being

Procambarus clarkii is currently recorded from 16 European territories. On top of being a vector of crayfish plague, which is responsible for large-scale disappearance of native crayfish species, it causes severe impacts on diverse aquatic ecosystems, due to its rapid life cycle, dispersal capacities, burrowing activities and high population densities. The species has even been recently discovered in caves. This invasive crayfish is a polytrophic keystone species that can exert multiple pressures on ecosystems. Most studies deal with the decline of macrophytes and predation on several species (amphibians, molluscs, and macroinvertebrates), highlighting how this biodiversity loss leads to unbalanced food chains. At a management level, the species is considered as (a) a devastating digger of the water drainage systems in southern and central Europe, (b) an agricultural pest in Mediterranean territories, consuming, for example, young rice plants, and (c) a threat to the restoration of water bodies in north-western Europe. Indeed, among the high-risk species, P. clarkii consistently attained the highest risk rating. Its negative impacts on ecosystem services were evaluated. These may include the loss of provisioning services such as reductions in valued edible native species of regulatory and supporting services, inducing wide changes in ecological communities and increased costs to agriculture and water management. Finally, cultural services may be lost. The species fulfils the criteria of the Article 4(3) of Regulation (EU) No 1143/2014 of the European Parliament (species widely spread in Europe and impossible to eradicate in a cost-effective manner) and has been included in the “Union List”. Particularly, awareness of the ornamental trade through the internet must be reinforced within the European Community and import and trade regulations should be imposed to reduce the availability of this high-risk species.     

Detecting subcanopy invasive plant species in tropical rainforest by integrating optical and microwave (InSAR/PolInSAR) remote sensing data,and a decision tree algorithm

In this paper, we propose a decision tree algorithm to characterize spatial extent and spectral features of invasive plant species (i.e., guava, Madagascar cardamom, and Molucca raspberry) in tropical rainforests by integrating datasets from passive and active remote sensing sensors. The decision tree algorithm is based on a number of input variables including matching score and infeasibility images from Mixture Tuned Matched Filtering (MTMF), land-cover maps, tree height information derived from high resolution stereo imagery, polarimetric feature images, Radar Forest Degradation Index (RFDI), polarimetric and InSAR coherence and phase difference images. Spatial distributions of the study organisms are mapped using pixel-based Winner-Takes-All (WTA) algorithm, object oriented feature extraction, spectral unmixing, and compared with the newly developed decision tree approach. Our results show that the InSAR phase difference and PolInSAR HH–VV coherence images of L-band PALSAR data are the most important variables following the MTMF outputs in mapping subcanopy invasive plant species in tropical rainforest. We also show that the three types of invasive plants alone occupy about 17.6% of the Betampona Nature Reserve (BNR) while mixed forest, shrubland and grassland areas are summed to 11.9% of the reserve. This work presents the first systematic attempt to evaluate forest degradation, habitat quality and invasive plant statistics in the BNR, and provides significant insights as to management strategies for the control of invasive plants and conversation in the reserve.     

黄河三角洲区域泥螺入侵与扩散研究进展

莱州湾西岸作为黄河三角洲的重要组成部分,位于渤海沿岸,滩涂岸线长而广阔、海水有机物质丰富、饵料充足,为底栖动物的生长提供了优越条件。为探寻黄河三角洲区域泥螺入侵历史,梳理总结扩散现状,探讨对当地传统生物造成的危害,保护黄河三角洲生物多样性和生态系统稳定。文章对历史资料和相关文献进行汇总整理。结果显示：2001年前莱州湾以及黄河口附近海域均无泥螺分布,现有泥螺种群来源于2001年人工引种。在黄河三角洲区域,泥螺分布范围持续扩大,向北已扩展至滨州沿岸潮间带海域,局部区域最高密度达160 ind/m2,被列为外来入侵物种,纳入了国家海洋局的生态监控体系中。泥螺与当地底栖贝类生物争夺营养和空间资源,产生种间竞争,导致种群生态位偏移。泥螺入侵成为优势种,建立了稳定的种群。