Biological Invasions最新文献

Biological surveillance at an invasion front is hindered by low population densities and, among animals, high mobility of target species. Using the barred owl (Strix varia) invasion of western North American forests as a test case, we tested real-time autonomous recording units (the ecoPi, OekoFor GbR, Freiburg, Germany) by deploying them in an area known to be occupied by the target species. The ecoPi passively record audio, analyze it onboard with the BirdNET algorithm, and transmit audio clips with identifiable sounds via cellular network to a web interface where users can listen to audio to manually vet the results. We successfully detected and lethally removed three barred owls, demonstrating that real-time acoustic monitoring can be used to support rapid interventions at the forefront of an ongoing invasion in which proactive management may be essential to the protection of an iconic native species, the spotted owl (S. occidentalis). This approach has the potential to make a significant contribution to global biodiversity conservation efforts by massively increasing the speed at which biological invasions by acoustically active species, and other time-sensitive conservation challenges, can be managed.

If an animal’s size, age and/or sex influence its vulnerability to an invasive species, the arrival of such an invader can cause rapid changes in the population demography of an affected species. We studied free-ranging varanid lizards (Yellow-spotted monitors, Varanus panoptes) at a site in tropical Australia during the influx of fatally toxic cane toads, Rhinella marina. Mortality was inferred from shifts in population structure, as well as the survival rates (time to death) of 107 radio-tracked lizards. Of 57 deaths whose cause was unambiguous, 32 were due to fatal poisoning by ingesting a cane toad; the other 25 lizards were consumed by pythons. Size and age structure shifted between years, such that the population post-invasion was dominated by smaller, younger lizards, and by females rather than males. Radiotelemetric monitoring confirmed that survival rates were reduced more in males than in females in the post-toad year, with males most at risk late in the dry-season, when food was scarce and females were nesting rather than foraging. Pythons disproportionately consumed larger female lizards during the nesting season. Toad-induced poisoning of adult male varanids (which are larger and bolder than females) likely produced a population that was more resilient to toad impact, but less easily surveyed by conventional techniques.

The shrub, Robinia hispida L., commonly known as the bristly locust, is a native to southeastern United States. It has, however, expanded its range within North America, and established invasive native-alien populations in several American states and Canada. Outside of North America, R. hispida has been introduced to Europe and Asia, where it has naturalised and is considered invasive. Notably, the presence of this shrub has never been reported outside of cultivation in Africa. Despite receiving little scientific attention compared to its congeneric species such as the global invader Robinia pseudoacacia L., R. hispida shares morphological and growth characteristics including rapid growth and a suckering habit. It occupies similar environmental niches in both native and introduced ranges, thriving in thin upland woodlands, woodland edges, thickets, fence rows, roadside embankments, banks of drainage canals, vacant lots, and overgrown waste areas. In South Africa, R. hispida was first recorded in a garden in Polokwane in 1986, while the first record outside of cultivation was near the town of Bethlehem in the Free State Province in 2023, and further surveys were conducted locating additional populations near the towns of Zastron and Clarens in 2024. The potential distribution of R. hispida in South Africa was modelled in MaxEnt using areas climatically representative of the species, based on the Koppen-Geiger climate classifications. The potential distribution includes areas of central South Africa, the east and south coast and the Mediterranean climates of the southern Cape. Management strategies suggested for R. hispida in South Africa, considering the small size of the populations, should include eradication efforts using mechanical and chemical means, followed by continuous monitoring to prevent re-emergence.

We aimed to investigate the presence of the copepod Pseudodiaptomus trihamatus in an estuary in Northeastern Brazil, from a long-term perspective (1987–2023), and its distribution in other nearby estuaries, after 30 years of invasion, especially considering its impacts on native congeneric species. We tested the following hypotheses: (i) The abundance of P. trihamatus increases over time and the abundance of native species decreases; (ii) The β diversity decreases over time; (iii) Copepod composition and β diversity differs over time. The study was carried out in six estuarines systems in Pernambuco, in the Northeastern Brazil. The investigation of long-term variation (1987–2023) was based on the Capibaribe River Estuarine System (CRES), while for the spatial variation (2020–2021), six estuarine systems were considered. We observed that P. trihamatus has occurred in CRES since 1991, 10 years before the first record of the species in Pernambuco. The abundance of P. trihamatus did not increase over time. Furthermore, β diversity increased over time, showing that the presence of P. trihamatus did not cause biotic homogenization through loss of biodiversity. In the spatial variation (2020–2021), we found P. trihamatus in four of the estuaries and was it the third most representative species of the family. The occurrence of P. trihamatus did not significantly affect the Pseudodiaptomidae family and the copepod assemblage, for either long-term or spatial variation. The undetected or negligible impact of P. trihamatus need to be monitored, to prevent a sleeper population from becoming highly abundant and, perhaps, disruptive in this region of Brazil.

Protected areas are key to global biodiversity conservation efforts. Yet, most protected areas globally face threats of biological invasions either by invasive non-native species established within the protected area or by the imminent establishment of invasive non-native species established in the surrounding landscapes. In face of growing biological invasions, protected area managers must be able to set prevention and control priorities for invasive non-native species management. In this study, we developed a new methodological approach to identify which protected areas should be prioritized for prevention and early detection and which should be prioritized for control of biological invasions. Our methodological approach analyzes the occurrence of invasive species within and around the protected areas and weights the influence of multiple existing pathways to calculate the probability of introduction of invasive species and colonization pressure for each protected area. We evaluated our priority setting model in 280 terrestrial and 42 marine protected areas in Brazil. For the terrestrial protected areas, 84 were classified as priority for prevention and early detection and 124 were classified as priority for control of biological invasions. For the marine protected areas, 25 were classified as priority for prevention and early detection and seven were classified as priority for control of biological invasions. Human population density and percentage of pasture cover surrounding the protected area were the most important factors for priority setting in terrestrial protected areas whereas number of aquiculture activities, density of waterways, distance to ports, distance to oil platforms, and distance from sinking points were the most important factors for priority setting in marine protected areas. In conclusion, the framework presented here provides an objective methodology for managers and stakeholders to decide where to invest their limited resources available for management of biological invasions in protected areas.

Broad infestations of invasive, non-native vegetation have transformed wetlands around the world. Ludwigia hexapetala is a widespread, amphibious invasive plant with a creeping growth habit in open water and an erect growth habit in terrestrial habitats. In the upper San Francisco Estuary of California, L. hexapetala is increasingly terrestrializing into marshes and this expansion may be facilitated by allelopathy. We conducted the first field-based study on L. hexapetala allelopathy to determine whether (1) three allelochemicals known to be exuded by L. hexapetala are expressed in situ, (2) the allelochemicals are detectable in leaves, soil, and water, and (3) allelopathic expression varies by season, salinity, and growth habit (open water “patch” vs. terrestrial marsh “interface” locations). Water, soil, and L. hexapetala leaves were collected in two freshwater sites and two oligohaline sites in the upper San Francisco Estuary in summer 2021, fall 2021, and spring 2022. Myricitrin and quercitrin, known allelochemicals, and salipurposid, a newly identified polyphenol, were detected in water, soil, and leaves. There were significant differences in allelochemical concentrations under fresh versus oligohaline conditions in water and soil, but not leaves. All three allelochemicals generally had higher concentrations in patch versus interface locations, suggesting that L. hexapetala allelopathy plays a greater competitive role in open water than terrestrial habitats. Leaf concentrations of each allelochemical varied seasonally; however, both myricitrin and salipurposid had heightened concentrations in spring. These results suggest that herbicide application in early spring may be most effective in controlling L. hexapetala terrestrialization from open water to marshes.

In agricultural systems, responsive management can mitigate the effects of risk and uncertainty by facilitating adaptation to changing conditions. A tool for evaluating management systems while accounting for risk and uncertainty is Probabilistic Cost Benefit Analysis (PCBA). This study used PCBA to contrast a new responsive disease management strategy against an existing prescriptive strategy. Fungicide application to prevent myrtle rust (MR) in NZ plant nurseries was used as a case study to test if the expected benefits of the responsive strategy justified the investment in potentially more frequent and costlier disease control. A MR risk generator was used to simulate disease progression. Empirical MR risk distribution functions were sampled to stochastically compare net benefits across scenarios, highlighting the potential impact of infrequent but significant disease incursions. Our results showed that the risk-based strategy was more effective at controlling the disease, especially for susceptible myrtle species in high-risk locations. The findings highlighted the essential role of fungicides in propagating highly MR-susceptible species, and that disease management, when responsive to risk, enhanced the efficiency of fungicide use. The Responsive strategy is discussed as an effective management option for nurseries under uncertainty of significant MR incursions. However, in less risky scenarios, the benefits of the responsive strategy were moderate, and operational considerations may favour the standard calendar-based approach. In such cases, the method provided here can help estimate the appropriate fungicide application interval and the associated MR risk.

Protected areas are expected to harbour fewer invasive plants due to the absence of anthropogenic disturbance and greater resistance of natural vegetation to invasion. Our study aimed to quantify the impacts of selected invasive plants on native plant species richness, diversity, and composition in five protected areas of Nepal spread across ~ 3403 km² at the Himalayan foothill. Lantana camara, Mikania micrantha, and Parthenium hysterophorus were selected as target species based on their abundance in the study area. For each species, 30 pairs of invaded and uninvaded plots of 10 × 10 m were sampled to record the presence and covers of all vascular plants. The impacts of invaders on species diversity were analyzed using linear mixed-effect models, those on plant community composition by direct gradient ordination. The analysis of merged data, including all studied invaders, showed that the invasions reduced native species richness and diversity, which decreased to less than half of the values recorded in uninvaded plots. Similarly, each of the three species had a significant negative impact on native species richness and diversity when tested separately, with M. micrantha having the greatest impact, followed by P. hysterophorus and L. camara. In addition, the invasion by L. camara explained the greatest percentage of variation in the species composition of the invasive species studied. The results support the invasion meltdown theory, as the invasion promoted the presence of other alien species in the invaded plots.

Invasive earthworms create widespread ecological changes after they are introduced. Non-native earthworms are transported mainly through anthropogenically-mediated activities, including fishing, agriculture, horticulture, and development. Here, we review the ways in which non-native earthworms are transported to new environments. Our conceptual framework involves invasion filters (human activities filter and climate & edaphic filter) that constrain which non-native earthworm species are transported within specific contexts. Differences in earthworms’ ecological behaviors, life cycle, and physiological tolerance of environmental conditions influence which species are transported and which regions can successfully be invaded. Within the human activities filter, we utilize the six invasion pathways that follow a continuum of human intention as laid out by Hulme et al. (J Appl Ecol 45(2):403–414, 2008). Five of these pathways are associated with human activity. Of these, the release, escape, and contaminant pathways are associated with commodities, and the stowaway plus corridor pathways with transportation infrastructure. Major human activities that transport invasive earthworms include the discarding of fishing bait, agriculture, composting and horticulture, and development (e.g., the construction of roads, trails, houses, or campgrounds), but the magnitudes that specific activities transport earthworms are vastly understudied. We conclude that more research needs to be conducted to understand the methods that transport non-native earthworms in order to slow their spread.

In the Great Plains region, the live bait industry relies on approved species of cultured and wild-harvested baitfish. The release of baitfish by anglers is prohibited in most locations, but angler compliance with these regulations can be low. Bait retailers can increase compliance with regulations by communicating with anglers about aquatic invasive species (AIS) risk and through their business practices. We conducted 66 telephone surveys with bait retailers in southeastern South Dakota from June to July 2023 to (1) characterize bait retailer practices that may influence AIS risk and (2) determine the extent and willingness of bait retailers to display educational materials to reduce AIS risk. Fathead minnows (Pimephales promelas) were the most sold species (96% of respondents), and most bait came from wholesale retailers (74%). However, 24% of bait retailers also occasionally bought from local bait harvesters. Non-advertised species were observed at least once in shipments by 35% of bait retailers, but retailers only encountered species they did not intend to order in 1% of their inspections. Regular inspections for non-advertised species in baitfish shipments were conducted by 74% of retailers. Most inspections occurred at the time of receiving a baitfish shipment (36%) or daily (36%). Bait retailers were interested in displaying provided AIS educational materials (80%), including posters and pamphlets (59%), stickers (41%), bait bags (39%), and keychains/boat key floats (36%). Displaying educational materials at bait retail locations may increase angler knowledge of AIS and compliance with bait disposal regulations.