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Calluna vulgaris-dominated heaths and moorlands are habitats of international conservation importance. Degradation has occurred throughout their range with Calluna typically being replaced by grass species. The cessation of grazing is often impractical and rarely results in the recovery of Calluna abundance when it is initially present at low cover. Thus the development of restoration methods is required; these should be practical at a large-scale, in remote areas and create suitable conditions for Calluna germination and establishment, whilst still allowing grazing to occur. A replicated field experiment was established on Nardus stricta and Molinia caerulea-dominated moorlands to test the efficacy of different grazing regimes and intervention techniques aimed at establishing Calluna. Disturbance (rotavation and trampling by animals) to create bare ground increased Calluna establishment. On the Nardus site, Calluna establishment was equally successful on rotavated and trampled plots, but rotavation was more successful on the Molinia site. Seeding with Calluna increased Calluna establishment irrespective of whether a seed-bank was present. At the Nardus site, 0.5 cow/ha for two months in summer led to Calluna establishment and growth similar to that of ungrazed plots and was more successful than a mixed grazing regime (1 ewe/ha plus 0.5 cow/ha for 2 months) or a sheep only regime (1.5 ewes/ha). The creation of small patches of bare ground, seed addition and low intensity grazing enabled the rapid establishment of Calluna on grass-dominated moorlands; such techniques may also be applicable in other habitats where restoration requires the addition of a single/few species and minimal intervention. 相似文献
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A change in the vegetation of UK moorland from Calluna vulgaris-dominated heath to Molinia caerulea- or Nardus stricta-dominated grassland is frequently deemed undesirable on economic and biodiversity grounds. Moorland vegetation restoration is an increasingly practiced management option. However there has been little research on the effectiveness of such management for aiding the restoration of other aspects of moorland biodiversity such as associated insect populations.We sampled Hemiptera and Lepidoptera assemblages from restored, degraded and C. vulgaris-dominated (target) moorland at eight restoration sites in England and Scotland. Vegetation assemblages and additional environmental variables were sampled at the same locations.Vegetation restoration aided the reassembly of moorland insects to a variable extent. Hemiptera restoration success was greatest at mechanically restored sites dominated by C. vulgaris. In addition to treatment, latitude best explained variation in the Hemiptera assemblage. A range of plant species, all either dwarf shrubs or graminoids, acted as further determinants. Lepidoptera restoration success was correlated most closely with the success of restoring the full diversity of the vegetation assemblage and was highest at sites restored by grazing control.The results demonstrate that vegetation restoration brings wider biodiversity benefits and that the form these take may depend on the restoration method used and consequent characteristics of the resultant vegetation assemblage. 相似文献
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Julie A MatarczykAnthony J Willis John A Vranjic Julian E Ash 《Biological conservation》2002,108(2):133-141
Environmental weed invasion threatens the biodiversity of native species. Unfortunately, managing these weeds may also affect biodiversity adversely. A recent example occurred when glyphosate, a herbicide used to control the highly invasive weed, bitou bush (Chrysanthemoides monilifera ssp. rotundata), accidentally drifted over a small population of an endangered shrub, Pimelea spicata. Following concerns that the affected population would not recover and, thereby, cause the local extinction of P. spicata, we conducted a series of glasshouse and field experiments to explore the impacts of glyphosate on this endangered species. Seedlings and young plants of P. spicata, in which the tap root was undeveloped, were killed by a single application of glyphosate. Older plants with a well developed tap root also died back initially, but about 50% of individuals re-sprouted. This re-growth was associated with a significant decrease in tap root diameter, implying that further disturbance, including repeated treatment with glyphosate, would kill plants by impairing their potential for recovery. Unlike some sclerophyllous native shrubs, the tolerance of P. spicata to glyphosate was limited, even when its growth was slowed artificially by limiting water availability. Winter applications of glyphosate to manage infestations of bitou bush will impact adversely on populations of P. spicata and may also affect the other rare and endangered species whose survival is threatened by this species, even though some natives are unaffected by the herbicide. Protecting native biodiversity from bitou bush will involve sustainable weed management that minimises impacts on non-target native species. 相似文献
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The effects of herbicides applied to a direct drilled and traditionally tilled wheat field on trap catches of the abundant Collembola and Formicidae were examined. Significantly higher abundances of Collembola and species richness of ants were found on the direct-drilled plots. A significant effect of the herbicides, bromoxynil (C7H3Br2NO) and hoegrass (diclofop-methyl), on the activity of two of the fourteen species of surface-dwelling Collembola was detected but no effect was observed on surface-active Formicidae. Jeannenotia stachi numbers were significantly more reduced on the direct-drilled compared to the traditionally tilled plot after herbicide treatment possibly because of higher predator abundance on the latter. In the short term, herbicides have a minimal effect on most species of surface-active arthropods although Collembola were more adversely affected than Formicidae. 相似文献
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A field experiment was carried out to investigate the impact of four different management treatments on the response of Calluna-dominated heathland to nitrogen additions of 0 or 30 kg ha−1 yr−1 at a lowland heath in Surrey, England. Post-management Calluna regeneration, growth and canopy development were significantly affected by both the form of management and by nitrogen addition. The effect of nitrogen on shoot growth was lower, in absolute terms, in those plots which had undergone more intensive management treatments. Seedling establishment was higher in plots which received a simulated accidental burn treatment, reflecting the greater proportion of bare ground and the high degree of physical disturbance associated with this treatment. Invasion by Deschampsia seedlings was increased by nitrogen addition, particularly in simulated accidental burn plots. In the long term, the need to maintain a low nutrient environment to favour Calluna dominance, particularly in the face of elevated nitrogen deposition, favours the use of managements which result in the export of a significant proportion of the organic nitrogen stores. However, further study is required to ensure that initial enhancement of seedling invasion by grass and other species, associated with these more intense managements, does not outweigh the long term benefits of associated nutrient removal. 相似文献
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Pauline M. Currey David Johnson René van der Wal Lucy J. Sheppard Rebekka R.E. Artz 《Soil biology & biochemistry》2011,43(3):495-502
To understand the implications of atmospheric nitrogen deposition on carbon turnover in peatlands, we conducted a 13C pulse labeling experiment on Calluna vulgaris and Eriophorum vaginatum already receiving long-term (5 years) amendments of 56 kg N ha−1 y−1 as ammonium or nitrate. We examined shoot tissue retention, net ecosystem respiration returns of the 13C pulse, and soil porewater DOC content under the two species. 13C fixation in Eriophorum leaves was enhanced with nitrogen addition and doubled with nitrate supply. This newly fixed C appeared to be relocated below-ground faster with nitrogen fertilization as respiration returns were unaffected by N inputs. By contrast, increases in 13C fixation were not observed in Calluna. Instead, net ecosystem respiration rates over Calluna increased with N fertilization. There was no significant label incorporation into DOC, suggesting a conservative strategy of peatland vegetation regarding allocation of C through root exudation. Greater concentrations of total DOC were identified with nitrate addition in Calluna. Given the long-term nature of the experiment and the high N inputs, the overall impacts of nitrogen amendments on the fate of recently synthesized C in Eriophorum and Calluna in this ombrotrophic peatland were surprisingly more moderate than originally hypothesized. This may be due to N being effectively retained within the bryophyte layer, thus limiting, and delaying the onset of, below-ground effects. 相似文献
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Pia L. Nielsen Louise C. Andresen Anders Michelsen Inger K. Schmidt Jane Kongstad 《Applied soil ecology》2009,42(3):279-287
Eutrofication is a threat against nutrient-poor habitats as increased amounts of nutrients in ecosystems may cause changes in the vegetation. Nitrogen (N) deposition leads to conversion of Calluna heathlands into graminoid dominated heath, but low availability of P may hinder or slow down this process.In this study the soil properties under two dominant heathland plants, the dwarf shrub Calluna vulgaris and the grass Deschampsia flexuosa, were investigated, with focus on nutrient content in the organic top soil and soil microbes during the main growing season and effects of nutrient amendments. The concentration of inorganic and dissolved organic N was significantly higher under D. flexuosa than C. vulgaris all though there were the same amounts of total N in the soil below the two species. N and P amendment enhanced available N and P in the soil, but added nutrients had little direct effects on microbes. The microbial biomass on the other hand was positively related to soil water content in fertilized plots indicating that this was due to an indirect effect of enhanced nutrient availability. Microbial N and P pools were respectively 1000 and 100 times higher than the pool of inorganic N and P, and microbes therefore may play an important role in regulating plant nutrient supply. Judged from responses of inorganic and microbial N and P concentrations to added N and P, N seemed to limit C. vulgaris and soil microbes below while P seemed to limit D. flexuosa and soil microbes below this species. There were lower rates of net nitrification, net ammonification and DOC and DON production rates during winter in the soil under C. vulgaris than below D. flexuosa, although all these rates were equal under the two species on an annual basis. This indicates that these microbial processes were taking place during winter but were affected by exudates from C. vulgaris. 相似文献
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The roosts of many IUCN-listed cave-roosting bat species are under threat from tourist development in SE Europe and other regions of the world. Much-needed conservation strategies require, among other information, an understanding of their roost movements and population dynamics, which can now be obtained relatively quickly using advanced models. We have studied the long-fingered bat, Myotis capaccinii, an obligate cave-dweller, in Dadia National Park, Greece. The species formed colonies of up to a few thousand individuals and was highly mobile, frequently switching summer roosts up to 39 km apart, even during late pregnancy. The bats migrated to distant hibernacula including a cave in Bulgaria 140 km NW of the Park. Adult recapture probabilities varied with season and sex: low female recapture rates in autumn, relative to spring and summer, indicated non-random temporary emigration following nursery colony dispersal. The opposite pattern was seen in males: increasing recapture rates in the autumn suggest that males gather in these roosts to mate with females in transit. Adult survival (0.86-0.94) was similar in females and males, similar in winter and summer, and comparable to recent estimates for other bats based on similar modelling techniques. Sex-based differences in juvenile recapture suggest female philopatry and male-biased dispersal. Our work shows that protection of M. capaccinii roosts must extend beyond the Park’s and indeed the country’s boundaries: its conservation requires large-scale, trans-national integrated conservation plans. Our results will apply to many other warm-temperate species with similar life history cycles. 相似文献
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Deanna P. Rokich Jack Harma Shane R. Turner Rohan J. Sadler 《Biological conservation》2009,142(4):850-869
Five experiments were implemented to collect information related to the effects of fluazifop-p-butyl (active chemical in grass selective herbicides, Fusilade® and Fusilade Forte™) on seed germination, seedling emergence, growth and health of species native to southwest Australia (a grass and non-grasses), together with several co-occurring introduced species (grasses and a non-grass). Experiments investigated effects of herbicide concentrations, seed burial depths, seed-sowing times since herbicide application and application locations (foliage versus soil). Both herbicides, at half to quadruple strength of recommended field application concentrations, adversely affected development of native and introduced species, both grasses and non-grasses. Herbicidal effects were observed during the seed germination phase, and if germination had occurred, during seedling emergence and, finally, during plant establishment. However, effects were more pronounced after seed germination, particularly on development of seedlings and plants, with retardation and/or discoloration of either radicles or shoots. Not unexpectedly, seedlings from seeds buried deeper in the sand medium (20 mm) struggled to emerge. Both herbicides demonstrated residual characteristics by impeding seedling emergence and growth from seeds sown at various dates (up to maximum test duration of 3 weeks) following exposure of the sand medium to the herbicides. Further, herbicide application to sand only, produced effects on 5-6 months old plants that were similar as application to foliage only, demonstrating herbicide uptake from sand. While the findings support independent research, they contradict the purported herbicide characteristics by commercial sources - grass selective, post-emergent, non-residual, rapid breakdown and active through foliar application only. Implications of these herbicides for biodiversity conservation are discussed. 相似文献
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Frank M. Chambers Dmitri Mauquoy Andy Gent Freya Pearson Peter S. Jones 《Biological conservation》2007,137(2):197-209
Many European blanket mires are degraded and contain few Sphagna. In Wales, more than half exhibit symptoms of degradation. We used palaeoecological techniques to chronicle recent vegetation history at two upland localities in South Wales to provide an understanding of the contribution of various factors in mire degradation and to aid wider conservation management strategies. The data suggest a major vegetation change post-dated the start of the industrial revolution. There was evidence for increased burning activity, but as this phenomenon was not present in all profiles it seems unlikely that fire was the principal or sole agent in vegetation change. Rather, increased atmospheric input, plus a change in grazing pressure, may have been responsible. The implications for conservation management are far-reaching. The present overwhelming dominance of Molinia at Hirwaun Common is unprecedented. So also is a local dominance of Calluna, shown in one area at Mynydd Llangatwg. Hence, the approbation often accorded to Callunetum needs to be tempered with the knowledge that its presence in the Mynydd Llangatwg landscape is not long-standing. Indeed, millennial-scale dominance of Sphagnum imbricatum characterizes the earlier record. Its demise and that of Drosera intermedia took place in historical times. Both localities show floristic impoverishment within the 20th Century, with relatively recent single-taxon supremacy. So, conservation management to reduce the current pre-eminence of Molinia would not run counter to long-established dominance; ways to achieve this are suggested. The methods used in this study have wide applicability in mire conservation. 相似文献
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The United Kingdom Overseas Territories (UKOTs) are globally important for a high diversity of endemic and threatened plant species but are poorly represented in plant ecological literature. This lack of ecological research is compounded by a lack of funding and skills. Cost effective approaches of compiling conservation relevant information are required. Here we present the first examination of a species from the UKOTs presented within the standard framework of a Biological Flora. This framework allows a convenient way to compile ecological information and assess missing data. The account reviews all available information on Euphorbia origanoides L. (Ascension spurge) from Ascension Island (South Atlantic Ocean) relevant to understanding its ecology and conservation, including soil chemistry, climate and plant community data. E. origanoides is an endemic perennial, found in dry, lava plains of Ascension Island with soils comprised of weathered volcanic scoria. E. origanoides has suffered habitat loss through the introduction of invasive species and survival in the wild is currently under threat. We relate the information gathered for this Biological Flora to the conservation of the species in the wild and propose the framework should be used as one way of compiling information relevant for conservation managers. The framework is beneficial as it allows an evidence-based approach to conservation but also permits the prioritisation of research and can help conservation managers to meet targets for the Convention on Biological Diversity and the Global Strategy for Plant Conservation. 相似文献
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Natural hybridization between plant species often occurs in disturbed habitats and it is generally considered a threat for rare and endangered species. A different situation occurs in Mediterranean food deceptive orchids, where hybridization is a common phenomenon, as a natural consequence of their unspecific pollination system.Here, we present molecular and ecological evidence from a hybrid zone between Orchis mascula and O. pauciflora in order to address the consequences of hybridization on local orchid evolution and to assess conservation priorities for hybrids and hybrid zones in orchid conservation programs.We find that, although hybrids among the two target taxa are formed relatively frequently, hybrid zones often consist of F1 individuals, whereas backcrosses and later generation hybrids appear to be either rare or absent, presumably as a consequence of post-zygotic reproductive barriers acting in these food-deceptive orchids. Experimental evidence further indicates that hybrids are less fit than the parental species in attracting pollinators and that parental taxa exhibit higher or similar fitness in sympatry compared to allopatric populations. Since introgression is not frequent as indicated by molecular analyses, fitness and phenotypic trait differences observed among sympatric and allopatric populations of the parental taxa may be a consequence of pollinator-mediated selection.Our experimental data confirm that hybridization is a natural phenomenon in food-deceptive orchids and that it does not pose a threat to their survival. Furthermore, sympatric zones provide the stage for evolutionary processes in orchids, and this peculiarity should be taken into account when devising orchid conservation strategies. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(17):2235-2246
Current knowledge about the behavior of forest species under herbicide treatment regarding selectivity, resistance, and fitotoxic effects is insufficient. This study assesses the selectivity of sulfentrazone and glyphosate on Hymenaea courbaril L. seedlings (jatoba) and the effects of this herbicide on the rhizospheric microbial activity of those plants. For this assessment, two experiments were conducted. In the first one, 10 treatments were compounded by the combination of two herbicides (glyphosate and sulfentrazone) applied in five doses (0.00, 0.09, 0.18, 0.35, and 0.70 L ha?1). The second experiment assessed effects of the combination of five doses of the herbicide sulfentrazone and two types of substrate (rhizospheric and nonrhizospheric cultivated with jatoba seedling). To assess the selectivity of seedling to the herbicide, visual assessments of toxicity were carried out 15, 30, 45, and 60 days after the application. To determine the effect of sulfentrazone on rhizospheric activity, the basal respiration and of microbial biomass carbon (CBM) associated with substrates was evaluated. A good tolerance of the seedling with the herbicide was observed even at higher doses, indicating potential use in control of weeds in areas of jatoba planting in the initial phase of development. Regarding microbiological indicators, it is verified that the evolution of carbon dioxide carbon (C-CO2) and CBM were effective in the presence of herbicides, which can constitute auxiliary tools for environmental-impact monitoring of the herbicides. 相似文献
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We used models integrating road maps, traffic volume, and snake movements to examine the potential for roads to contribute to mortality in two species of water snakes that differ in their vagility, use of terrestrial habitats, and conservation status. Road networks and traffic volumes typical of three regions in Indiana, USA, may account for mortality of 14-21% of the population per year in the more vagile, terrestrial, and imperiled copperbelly water snake (Nerodia erythrogaster neglecta) but only 3-5% mortality in the more sedentary, aquatic, and common northern water snake (Nerodia sipedon). The majority (>91%) of road crossings and associated mortality are predicted to occur during overland migrations to other wetlands, suggesting roads bisecting travel routes between wetlands may function as mortality sinks. Our models highlight the proportionately greater risk of mortality for the more vagile and imperiled species, N. e. neglecta, and suggest current wetland conservation strategies that focus on the wetland alone are unlikely to adequately protect wetland biodiversity from certain types of anthropogenic habitat modification. What is needed is a landscape approach to wetland conservation that considers not only the quality of wetlands and nearby terrestrial habitats, but also ensures that terrestrial corridors between wetlands remain permeable and offer safe passage for wildlife. 相似文献
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Kunzea sinclairii is a local endemic on Great Barrier Island, northeastern New Zealand. While variously ranked as vulnerable and endangered in the past, we show that this species is naturally uncommon and under no threat of extinction. Previous assessments of its conservation status have been based on inadequate knowledge of its ecology. K. sinclairii is a rupestral species whose optimum habitat is low shrubland on rhyolitic rock outcrops and cliffs. Because of past logging and burning of forest adjacent to the habitat to which it is adapted, K. sinclairii expanded its range. However, in regeneration back to forest, K. sinclairii is being excluded as it is overtopped by other species. This has led to the impression that it is declining. Similarly, a suggestion that K. sinclairii could be threatened by hybridisation with the more abundant closely related K.ericoides is not supported as the hybrids are confined to the disturbed sites created by logging and fire. This case study highlights the importance of having a good understanding of the ecology of uncommon plant species before making decisions on their conservation. Natural rarity does not itself necessarily equate with increased extinction risk and these taxa should not be classified as threatened. 相似文献
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Nadeem Iqbal Sudheesh Manalil Bhagirath S. Chauhan Steve W. Adkins 《Archives of Agronomy and Soil Science》2013,59(13):1885-1899
ABSTRACTGlyphosate-resistant (GR) weeds are the biggest concern for all cotton stakeholders worldwide. Currently, 43 weeds species are resistant to glyphosate and the number is increasing at an alarming rate. Soil residual/pre-emergence (PRE) herbicides like Pendimethalin and S-metolachlor can be effectively used for the control of GR weeds; however, their use is very limited at farmer’s side due to the adoption of herbicide-tolerant technology with complete reliance on glyphosate. The present study was conducted to evaluate the performance of PRE and post-emergence (POST) herbicides in glyphosate-tolerant (GT) cotton. The herbicide treatments were pendimethalin and S-metolachlor as PRE-residual, and glyphosate was applied as POST at 20 days after sowing (DAS) either alone or in combination with other herbicides like S-metolachlor, pendimethalin, and haloxyfop. A second application of glyphosate was made at 35 DAS. Results revealed that pendimethalin and S-metolachlor treatments gave 100% suppression of all dominant weeds and increased lint yield by 310–350% as compared to weedy control. In contrast, glyphosate applied once and twice, gave weed biomass reduction of only 10–86%, and increased lint yield by 136–185% over weedy control. This research established that PRE application of pendimethalin and S-metolachlor can be included in the weed management program of GT cotton. 相似文献
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Dramatic changes have been documented in New Zealand's vertebrate faunas since human settlement, involving major declines and extinctions, but over recent years few species have declined in numbers so rapidly as the terrestrial Archey's frog Leiopelma archeyi (Anura: Leiopelmatidae). Long-term monitoring over more than 20 years revealed a major population reduction of the species over 1996-2001 and L. archeyi is now classified as Nationally Critical under the New Zealand threat classification system. The decline progressed northwards in the Coromandel ranges, and mostly larger (female) frogs survived. On a 100 m2 study plot at Tapu Ridge, annual population estimates averaged 433 frogs (SE ±32) over 1984-1994, declining by 88% to average 53 frogs (SE ±8) over 1996-2002. A mean annual survival rate of 82% for most years declined to 33% over 1994-1997. There is mounting evidence to suggest that disease is the major agent of decline, supported by (1) the rapidity and severity of decline, (2) the progressive (south to north) nature of decline, and (3) finding frogs with chytriodiomycosis from Batrachochytrium dendrobatidis at the time of decline. Surprisingly, sympatric populations of the semi-aquatic Leiopelma hochstetteri have not declined dramatically, nor has a western population of L. archeyi at Whareorino, despite chytridiomycosis occurring in some frogs there. Sustaining and restoring populations of L. archeyi in New Zealand raises major challenges for conservation management. 相似文献
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Diogenis F. Ferreira-Junior Renato Almeida Sarmento Althiéris de Souza Saraiva Renata Ramos Pereira Marcelo Coutinho Picanço João L. T. Pestana Amadeu M.V.M. Soares 《Water, air, and soil pollution》2017,228(10):390
Glyphosate is an herbicide commonly used worldwide for weed control and generally applied as part of a formulated product, such as Roundup. Contamination of surface water by glyphosate-based herbicides can cause deleterious effects in organisms, mainly in aquatic systems near to intensive agricultural areas (e.g., transgenic soybean crops). Given the lack of toxicological information concerning effects of glyphosate-based herbicides on tropical aquatic ecosystems, we aimed to evaluate the lethal and sub-lethal effects of Roundup Original® on the dipteran Chironomus xanthus. The endpoints evaluated included survival, growth, and emergence. The results showed that the 48 h LC50 for glyphosate to C. xanthus was 251.5 mg a.e./L. Larval growth of C. xanthus was reduced under glyphosate exposure (LOEC for body length = 12.06 mg/L; LOEC for head capsule width = 0.49 mg/L). No effects were observed in terms of cumulative percentage of imagoes emergence. However, low concentrations of glyphosate caused delayed emergence of females (at 1.53 mg/L) and induced fast emergence of males (at 0.49 mg/L), compared to control treatment. The deleterious effects of environmental relevant concentrations of glyphosate (0.7 mg/L) observed in terms of C. xanthus growth and development suggest that glyphosate-based herbicides can have negative consequences for aquatic non-target invertebrates such as Chironomus. Multigerational assays are needed to assess the long term effects of glyphosate on C. xanthus populations. Finally, our study adds ecotoxicological data on the effects of glyphosate-based herbicides on tropical freshwater invertebrates. 相似文献