Frontiers in Ecology and the Environment最新文献

Accurate estimates of the costs of land protection are useful for understanding where biodiversity conservation goals can be achieved at the lowest cost to society. However, because of the scarcity of high-quality cost maps for tropical countries, conservation planning studies often ignore cost or rely on untested proxies, such as agricultural rent or land-use intensity. Here, we show how analysts can estimate land protection costs using original data of public land acquisitions, global predictor datasets, and simple machine-learning models. For the Colombian Andes, a global biodiversity hotspot, we found that the principal driver of the cost of land protection is urban proximity, not agricultural rent. We derived cost estimates that predict public land protection costs more accurately than available cost proxies and identified new protection priorities for 143 threatened bird species. A more systematic collection of cost records of land protection will help inform public decisions on national and global biodiversity protection priorities.

Fireworks are important elements of celebrations globally, but little is known about their effects on wildlife. The synchronized and extraordinary use of fireworks on New Year's Eve triggers strong flight responses in birds. We used weather radar and systematic bird counts to quantify how flight responses differed across habitats and corresponding bird communities, and determined the distance-dependence of this relationship. On average, approximately 1000 times as many birds were in flight on New Year's Eve than on other nights. We found that fireworks-related disturbance decreased with distance, most strongly in the first five kilometers, but overall flight activity remained elevated tenfold at distances up to about 10 km. Communities of large-bodied species displayed a stronger response than communities of small-bodied species. Given the pervasive nature of this disturbance, the establishment of large fireworks-free zones or centralizing fireworks within urban centers could help to mitigate their effects on birds. Conservation action should prioritize avian communities with the most disturbance-prone, large-bodied bird species.

Yellow-headed (Xanthocephalus xanthocephalus) and red-winged (Agelaius phoeniceus) blackbirds coexist in marshes across North America. Pictured here at Iona Beach Regional Park in Vancouver, British Columbia, males of each species compete for nesting areas. In wetlands across their overlapping ranges, yellow-heads are dominant over red-wings, pushing them out of valuable marsh real-estate to secure the best nesting places.

Unfortunately, since the construction of Vancouver International Airport in 1968 and its expansion in subsequent years, both species have lost substantial extents of marsh habitat. Given their dominant–subordinate relationship, one might expect that habitat loss should disproportionately impact the subordinate red-wings, since they get last choice at nesting habitat, which might limit their reproductive success. Today, however, Iona Beach supports a healthy and abundant population of red-wings, and usually hosts only a few yellow-heads. Indeed, over the past half-century, the population of yellow-heads at Iona Beach has decreased ~95%, down from an estimated 70 individuals in 1970 to only 1–3 nowadays (Campbell RW, Dawe NK, McTaggart-Cowan I, et al. 2001. The Birds of British Columbia. Volume 4. Royal British Columbia Museum Victoria. Vancouver, Canada: UBC Press).

Despite their dominance, the yellow-headed blackbirds of Vancouver have seemingly been more negatively impacted by habitat loss and degradation than their subordinate red-winged cousins. Does their dominant behavior make yellow-heads more vulnerable to change? Are red-wings more tolerant of anthropogenic disturbances? Over the next decade, the potential extirpation of yellow-headed blackbirds from Iona Beach calls into question which blackbird genuinely is the dominant species. Of course, none of this stops the remaining few yellow-heads from bullying the abundant red-wings out of prime nesting space. At least population decline has not adversely impacted their yellow-headed ego!

Distributed within tropical to temperate regions globally, the little egret (Egretta garzetta) is an aquatic bird that occupies a wide range of inland and coastal habitats (Collins Bird Guide 2011, 2nd edn; New York, NY: HarperCollins).

While monitoring avifauna in the Tanagro River (Sala Consilina, Italy), we were alerted about a little egret that was unable to fly and appeared to be stuck in the mud. After a human intervention, it became clear that the bird had one foot trapped within the closed shell of a unionid bivalve (photos courtesy of Carmen Cavallo).

To capture food in wetlands and on mudflats, E garzetta and other herons commonly rely on a technique known as “foot stirring” or “foot paddling”. Using this method, a heron will extend one leg into the substrate and then rapidly vibrate the submerged foot, thereby disturbing and forcing any hidden or benthic organisms from the subsurface to the surface; at that point, the bird will then stab its beak at any prey that attempt to escape from the disturbance (Wilson Bull 1959; biostor.org/reference/204432). It is highly possible that, while engaging this technique, the observed little egret became trapped by the bivalve.

Although similar events between shorebirds and marine bivalves have been documented (Waterbirds 1999; doi.org/10.2307/1522003), this is to the best of our knowledge the first recorded instance between an aquatic bird and a freshwater unionid. Europe hosts a large unionid biota, including the Chinese pond mussel (Sinanodonta woodiana), one of the largest (130–250 mm long) species worldwide and an eminent invader in our study area. While it is unknown how frequently such events may occur, this potential mortality source for native birds might need to be included among putative impacts of unionid bivalve species, such as the above-mentioned non-native taxon.

Antagonistic interactions between frogs and insects are generally well-documented. In typical predator–prey interactions, these taxa feed on one another at different life stages. Moreover, insects can function as disease vectors or as parasites of frogs, an example being myiasis-causing flies. However, certain antagonistic interactions between frogs and insects are poorly known, specifically interactions that are mediated by sensory cues such as sound or smell. Here, we report an unusual association between Hyloscirtus lindae (Hylidae) and moth flies (Diptera: Psychodidae, Sycoracinae).

On 26 September 2021, JC observed more than 50 individual moth flies (Sycorax sp) on one male H lindae in a high-elevation Andean cloud forest (around 3000 m above sea level) within Ecuador's Napo province. The male tree frog was actively calling from a Guadua bamboo, at 1.5 m above the ground, under a light rain, close to a small creek. Meanwhile, male and female moth flies interacted with each other on the frog while the frog was calling. This reproductive behavior, known as lekking, has been previously observed in moth flies of the island of Borneo in Southeast Asia, specifically upon frogs of the Bufonidae, Microhylidae, and Megophryidae families. Similarly, in Ecuador, male moth flies are suspected to congregate on frogs to locate female moth flies with which to mate. Sycorax moth flies have been documented forming leks on actively calling male frogs, who advertise their presence to conspecific females through acoustic vocalizations. One possible explanation for how moth flies locate male frogs is through eavesdropping of the male frog advertisement signal. However, no study has tested this behavior to date. It has been previously suggested that moth flies form leks on male frogs because it provides an opportunity for lekking female moth flies to partake of a blood meal after copulating; however, we did not observe feeding on this occasion.

As keystone structures in urban ecosystems, trees are critical to addressing many of the current livability, health, and environmental challenges facing cities. Every day, trees are removed from urban landscapes as part of routine management. These tree removals are an opportunity for implementing manipulative experiments to directly measure the social and ecological functions of trees. Here we review the kinds of tree removals that commonly occur in cities, assess the relevant opportunities that arise for research–practice partnerships, and discuss the challenges posed when implementing experiments of this nature. We argue that experimental studies on the routine removal of urban trees will improve and expand the mechanistic understanding of how trees support biodiversity and human well-being in cities beyond current knowledge, which is largely based on correlative studies. Finally, we highlight the opportunity for experiments to be co-designed by scientists and urban land managers, and how “learning while doing” can generate tangible research impacts and improve urban forest decision making.

Prescribed fire is an important management tool for restoring fire-adapted ecosystems and mitigating the risk of high-severity wildfire in the North American Mediterranean climate zone (NAMCZ), much of which was historically characterized by frequent low- to moderate-severity fire. For over a century, policies that excluded fire, curtailed Indigenous cultural burning, and prioritized timber harvesting have, in combination with anthropogenic climate warming, driven large-scale, high-severity fires that are wreaking ecological and socioeconomic havoc. Despite its recognized need, the use of prescribed fire at appropriate scale has been slow to occur. We describe some of the principal obstacles to increasing the application of prescribed fire in the NAMCZ and suggest four strategies for policy makers and high-level managers to overcome them: (1) redoubling federal and state agency commitment and rewarding assertive leadership, (2) increasing funding for prevention-focused management (as opposed to suppression), (3) building capacity through cooperation, and (4) expanding monitoring to inform burn strategies and adaptive management.