What's up? Perspectives from the first international forest canopy conference at Sarasota, Florida, 1994

Journal ArticleJumars, caribineers, pole pruners, tree bicycles, Bosun's chairs, booms, peconhas . . . these terms are not listed in most biological dictionaries. Nor are construction cranes or large treehouses or hot-air dirigibles listed as priority equipment for any scientific laboratories. But these are the essential tools required to provide some of the exciting results reported at the recent First International Forest Canopy Conference during November 1994 at The Marie Selby Botanical Gardens in Sarasota, Florida

Sacred fig trees promote frugivore visitation and tree seedling abundance in South India

While sacred groves (forest fragments protected for religious reasons) are widely acknowledged to have a beneficial effect on biodiversity conservation, the ecological benefits of individual sacred trees remain unknown. Fig trees are present as sacred trees in humandominated landscapes across South Asia and are considered keystone species for wildlife in tropical forests. If frugivores continue to visit fig trees in disturbed landscapes, they may deposit seeds of other tree species beneath fig canopies, ultimately facilitating forest regeneration. We studied whether sacred fig trees in Tamil Nadu, India can facilitate seed dispersal in human-dominated landscapes. We quantified abundance of sacred fig trees at the study site, assessed whether seed-dispersing frugivore visitation to fig trees is affected by human disturbance, and compared tree seedling density beneath fig trees and open areas. We found that some species of frugivorous birds and bats will visit large fig trees in conditions of high human disturbance and that tree seedling density is significantly higher under sacred trees compared to open areas. By promoting frugivore activity, sacred fig trees may have a beneficial effect on biodiversity conservation in human-dominated landscapes

Standard-Level Herbivory in an Old-Growth Conifer Forest Canopy

Herbivory is an important ecological process in forest canopies but is difficult to measure, especially for whole stands. We used the Wind River Canopy Crane in Washington State to access 101 randomly-located sample points throughout the forest canopy. This provided a relatively quick and convenient way to estimate herbivory for a whole stand. The overall level of herbivory was estimated at 1.6% of leaf area. The distribution was strongly skewed to the lower canopy where broad-leafed species experienced higher levels of herbivory. Herbivory averaged 0.3% in conifers and 13.5% in broad-leafed species. Fully half of the sample points had no detectable herbivory. Herbivory in this old-growth conifer forest is among the lowest levels published for forests around the globe and may reflect the general levels of herbivory in temperate coniferous forests during nonoutbreak conditions. Our whole-stand estimate is the first attempt at measuring herbivory for an entire forest stand in the Pacific Northwest

Extending our scientific reach in arboreal ecosystems for research and management

The arboreal ecosystem is vitally important to global and local biogeochemical processes, the maintenance of biodiversity in natural systems, and human health in urban environments. The ability to collect samples, observations, and data to conduct meaningful scientific research is similarly vital. The primary methods and modes of access remain limited and difficult. In an online survey, canopy researchers (n = 219) reported a range of challenges in obtaining adequate samples, including ∼10% who found it impossible to procure what they needed. Currently, these samples are collected using a combination of four primary methods: (1) sampling from the ground; (2) tree climbing; (3) constructing fixed infrastructure; and (4) using mobile aerial platforms, primarily rotorcraft drones. An important distinction between instantaneous and continuous sampling was identified, allowing more targeted engineering and development strategies. The combination of methods for sampling the arboreal ecosystem provides a range of possibilities and opportunities, particularly in the context of the rapid development of robotics and other engineering advances. In this study, we aim to identify the strategies that would provide the benefits to a broad range of scientists, arborists, and professional climbers and facilitate basic discovery and applied management. Priorities for advancing these efforts are (1) to expand participation, both geographically and professionally; (2) to define 2–3 common needs across the community; (3) to form and motivate focal teams of biologists, tree professionals, and engineers in the development of solutions to these needs; and (4) to establish multidisciplinary communication platforms to share information about innovations and opportunities for studying arboreal ecosystems

Forest Canopies

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“Canopy-Less” Monitoring of Biodiversity and Climate Change: Signs of a Leaky Roof

Forest canopies are considered the last biotic frontier, and studies of canopy biota and related processes are just beginning to emerge in some parts of the world. Monitoring changes in biodiversity and related processes have gained much significance in the few last decades, particularly due to climate change. In addition, changes in biodiversity have been addressed by incorporating monitoring at various spatial and temporal scales that range from landscape-level changes, ecosystem dynamics, to population and species-level processes over extended time scales

Vicissitudes of leaves in a tropical rain forest in Madagascar

A sample of 1834 leaves from 83 plants in 26 families was collected in tropical rain forest in Madagascar from three vertical strata: top of emergent trees (up to 37 m), top of trees in upper canopy (about 22 m), and shrubs and saplings at ground level. These leaves were examined for damage by seven different agents: fungi, epiphyllae, mechanical injury, galls, leaf miners, grazing insects and skeletonizing insects. Fungi affected more than 60% of the leaves and grazing insects 45-65%, with other agents each affecting 3-30%; fewer than 4% of the leaves escaped unscathed by any agent. Individual leaves were attacked by up to five agents. There was a sharp decline in proportion of leaves affected by fungi, leaf miners, epiphyllae and mechanical breakage with increasing category of severity. Grazing insects, mechanical injury, and perhaps galls, had greater impact at ground level than in the canopy, with fungi and skeletonizing insects showing the opposite pattern. Leaf miners had lower incidence in the canopy than elsewhere. The observed vertical stratification means that a tree not only needs to balance its defences to meet multiple threats in any stratum, but must adapt to a different suite of challenges during its lifetime. Attack by grazing insects and fungi are major challenges for saplings at ground level, but with increasing height above the ground fungal attack on leaves becomes more prevalent, but attack by grazing insects less so

Evidence for Three-Toed Sloth (Bradypus variegatus) Predation by Spectacled Owl (Pulsatrix perspicillata)

We detected the nighttime death of a radio-collared three-toed sloth (Bradypus variegatus) with an automated radio telemetry system in a Panamanian moist forest. Forensic evidence collected at the fresh carcass, including five pairs of zygodactyl puncture wounds, and the consumption of only soft tissue, suggests that the predator was a large owl, probably Pulsatrix perspicillata. Telemetry data, feces in the sloths' rectum, and old sloth feces at the base of the tree near the carcass suggest that the sloth was descending to the ground to defecate when it was killed. If correct, this is the first record of P. perspicillata killing such a large prey, highlighting the importance of crypsis, and not self-defense, as sloths' anti-predator strategy. This event also suggests there are high risks for sloths climbing to the ground to defecate, a puzzling behavior with no clear evolutionary advantage discovered yet.publishe