Frontiers in Ecology and the Environment最新文献

In June 2022 during the Tsuyu, a month-long season of persistent light rain unique to East Asia, I observed Diphylleia grayi flowers taking on a fantastic glass-like appearance in Nagano, Japan. Endemic to Japan and Sakhalin but distributed mostly in central Japan, the species is known informally as the “skeleton flower” outside of Japan. In dry weather, the petals of the skeleton flower appear white because light is diffusely reflected by numerous air-filled gaps in their cellular structure. When these gaps become filled with rain, however, the petals become transparent – a phenomenon that has attracted the attention of materials scientists (ACS Appl Mater Interfaces 2018; doi.org/10.1021/acsami.8b12490). Notably, the petals do not become transparent immediately after rain begins to fall; rather, light rain must fall continuously for about one day. Also, even after the weather clears, the petals remain temporarily transparent, until they dry.

Three Diphylleia species are known. In addition to D grayi, the familiar skeleton flower, Diphylleia sinensis occurs in central China, and Diphylleia cymosa is found in the southern Appalachian Mountains of the southeastern US (J Arnold Arbor 1984; doi.org/10.5962/p.36691). However, it is not known whether the flower petals of these two species also become transparent during rainy weather. If transparent petals are unique to D grayi, they may be an adaptation to the Tsuyu. What ecological function might the transparent petals have? Do flowers with transparent petals provide signals for pollinating insects? Is it possible to discern whether insect pollinators are more or less likely to visit flowers with transparent petals versus those with white petals, despite the potentially confounding presence of rain?

The parasitoid wasp Hymenoepimecis bicolor (Ichneumonidae) is able to manipulate the web-building behavior of its host, the golden silk orb-weaver Trichonephila clavipes (Araneidae). The host spider constructs a modified and complex web, which serves not only as a stable platform to suspend the wasp larva's cocoon but also as a barrier against hyperparasitoids and potential predators. Before depositing an egg on the host spider's abdomen, the H bicolor female immobilizes the spider by inserting its ovipositor – and releasing paralyzing substances – into the spider's mouth. Selecting a host of the proper size is essential: too small a spider may provide an insufficient source of food for the developing larva, whereas too large a spider may pose a serious risk during host interception and immobilization.

The attacking and subduing behaviors of polysphinctine wasps are not well known but may involve sophisticated sequences, including pulling a thread of the intended host's web with the foreleg, imitating struggling prey, to attract the spider (Entomol Sci 2009; doi.org/10.1111/j.1479-8298.2009.00338.x) and waiting for an opportunity to attack while resting on the web's non-viscid barrier threads (Naturwissenschaften 2007; doi.org/10.1007/s00114-006-0177-z). The above-described direct attack behavior of H bicolor, however, is preceded by a short period in which the wasp hovers around the potential host. Would it be possible for the female wasp to correctly evaluate the risks and quality of their potential hosts with just a quick visual inspection? Are chemical cues involved in host selection?

Several arthropod species, including caterpillars and spiders, commonly construct leaf-based shelters in the form of rolls, tents, and tiers for protection from predators and extreme physical conditions, affording them safety during development and reproduction. By building such shelters, these organisms qualify as ecosystem engineers (Neotrop Entomol 2016; doi.org/10.1007/s13744-015-0348-8), indirectly facilitating arthropod diversity on host plants (Arthropod-Plant Interact 2019; doi.org/10.1007/s11829-018-9661-6).

In the Cerrado Rupestre vegetation of southeastern Brazil (Nat Conserv -Bulgaria 2022; doi.org/10.3897/natureconservation.49.89237), we observed a gall-forming species of nematode that also induces a plant's gall-infested leaves to roll – the first recorded case, to the best of our knowledge (Ecol Entomol 2021; doi.org/10.1111/een.12993). The microscopic (600 μm) nematode Ditylenchus gallaeformans induces galls on the shrub Miconia ligustroides. As the galls develop over time, they cause the undersides of the leaves to curl, forming rolls roughly 20 mm in diameter (top). The interiors of the rolled leaves with attached galls are frequently colonized by many arthropod species, especially spiders, which deposit thick layers of silk to envelop and protect their egg sacs (bottom). As compared to host plants with intact (unmodified) leaves, host plants with gall-induced rolled leaves, which remain on the plants for approximately eight months, are associated with higher arthropod abundance and diversity (Ecol Entomol 2021; doi.org/10.1111/een.12993).

By diverting nutrients to feed the nematode larvae within them, the galls directly damage the host plants. At the same time, however, the galls may indirectly protect host plants from herbivory, given that the spiders that take refuge in these rolled structures repel sap-sucking and chewing insects (Ecol Entomol 2021; doi.org/10.1111/een.12993). Does gall presence have a net positive or negative effect on host plants? In addition, could galls accelerate the decomposition rates of the fallen infected leaves?

Flagship species are an important tool for mobilizing support for conservation. Here, we extend this concept to include individual organisms, whose characteristics, fates, and connections to people can garner public attention, attract conservation support, and spur activism. Flagship individuals typically share a similar suite of characteristics, including (1) species-level traits associated with charisma; (2) individual traits that are unique or distinctive; (3) a high degree of exposure to humans; and (4) a known, noteworthy life history or fate. The interplay between these characteristics and human agency establishes unique connections between flagship individuals and people, and generates widespread media attention. We discuss how the selection and promotion of flagship individuals can inspire empathy and, ultimately, conservation action. Finally, we identify the limitations of the flagship individual approach, while arguing that, if carefully and strategically implemented, it has the potential to produce substantial benefits for conservation policy and practice.

New investments in conservation are needed to halt and reverse the rapid and extensive changes to ecosystems driven by growing human demands for natural resources. A major barrier is matching viable financing solutions to conservation projects. Recent conservation finance studies catalog available financing options but do not provide adequate guidance on which financing pathways are suitable for a particular conservation project. Studies in the natural capital literature identify activities that best serve the conservator's objectives but typically fail to address the question of how to pay for them. We attempt to bridge these literature sources by providing a framework for identifying the specific conditions that must be satisfied by a project in order for an existing financing mechanism to be viable. Notably, our framework quickly reveals financing approaches that can be eliminated. We demonstrate the utility of this approach through conservation case studies on establishment of native forests, coral reef restoration, oyster restoration, and island biosecurity.

Given declines in biodiversity and ecosystem services, funding to support conservation must be invested effectively. However, funds for conservation often come with geographic restrictions on where they can be spent. We introduce a method to demonstrate to supporters of conservation how much more could be achieved if they were to allow greater flexibility over conservation funding. Specifically, we calculated conservation exchange rates that summarized gains in conservation outcomes available if funding originating in one location could be invested elsewhere. We illustrate our approach by considering nongovernmental organization funding and major federal programs within the US and a range of conservation objectives focused on biodiversity and ecosystem services. We show that large improvements in biodiversity and ecosystem service provision are available if geographic constraints on conservation funding were loosened. Finally, we demonstrate how conservation exchange rates can be used to spotlight promising opportunities for relaxing geographic funding restrictions.

Although human reshaping of the nitrogen (N) cycle is well established, contributions of individual N sources to riverine and coastal eutrophication are less certain. Urban N fluxes are potentially substantial, particularly from sewer overflows. Results from four longitudinal surveys in rivers in and around the city of Pittsburgh, Pennsylvania, were used to characterize N chemistry and isotopic composition and were compared with LOADEST-model-derived total N (TN) flux budgets from three urban areas along the Ohio River (Pittsburgh, Pennsylvania; Cincinnati, Ohio; and Louisville, Kentucky). Triple nitrate isotopes reveal that riverine nitrate in the Pittsburgh region is dominated by wastewater inputs despite high atmospheric deposition rates. Our budget estimates demonstrate that the magnitude of urban N yields is comparable to yields reported for agricultural watersheds and that these high urban N yields cannot consist of permitted, point-source discharges alone. Our results reveal that nonpoint sources in urban systems represent an important but overlooked source of TN to overall riverine budgets.