Tourism can be a powerful tool for wildlife conservation if well controlled and responsibly managed. Apex predators constitute particularly attractive subjects for tourism, but simultaneously they may generate conflict with local communities. Harpy Eagles Harpia harpyja are the largest eagle species and are highly sought-after by ecotourists. The last stronghold of the Harpy Eagle is the Amazon Forest, which is being deforested for cattle ranching. We tested methods for developing Harpy Eagle ecotourism as a potential tool to harmonize these issues. Using camera traps, we collected data on timing of Harpy Eagle visits to their nests, as well as on probabilities of viewing an eagle. Harpy Eagles can only be seen predictably during the first 12 of the 30–36 month nest cycle. In nests with nestlings (up to 5–7 months), adults are visible on a daily basis, and this period lasts 16.6% of the nesting cycle, demanding a minimum of 13, 17, and 26 nests to have at least one nest with a nestling on 90%, 95% and 99% of the days. After this 5–7 month window, we found that two and 4.16 days spent at nests afforded high probabilities of sighting a fledgling or adult eagle, respectively. Harpy Eagles were mainly active at the beginning and the end of the day. Activity core lasted 6.5 decimal hours for adults, peaking at 10h00, and 7.45 decimal hours for fledged eagles, peaking at 15h00. Our results demonstrate that Harpy Eagles fit several criteria for a viable wildlife attraction: predictable in activity and location, viewable, and diurnal, even though at the same time they are considered a rarity. In a broader perspective, Harpy Eagle tourism shows every indication of being a significant tool for more robust rainforest conservation.

Most oviposition by Helicoverpa zea (Boddie) occurs near the top of the canopy in soybean, Glycine max (L.) Merr, and larval abundance is influenced by the growth habit of plants. However, the vertical distribution of larvae within the canopy is not as well known. We evaluated the vertical distribution of H. zea larvae in determinate and indeterminate varieties, hypothesizing that larval distribution in the canopy would vary between these two growth habits and over time. We tested this hypothesis in a naturally infested replicated field experiment and two experimentally manipulated cage experiments. In the field experiment, flowering time was synchronized between the varieties by manipulating planting date, while infestation timing was manipulated in the cage experiments. Larvae were recovered using destructive sampling of individual soybean plants, and their vertical distribution by instar was recorded from three sampling points over time in each experiment. While larval population growth and development varied between the determinate and indeterminate varieties within and among experiments, we found little evidence that larvae have preference for different vertical locations in the canopy. This study lends support to the hypothesis that larval movement and location within soybean canopies do not result entirely from oviposition location and nutritional requirements.

Immense stands of bald cypress [Taxodium distichum (L.) Rich.] make it difficult for herbicide applicators to access the free-floating fern giant salvinia (Salvinia molesta Mitchell), which can be found growing under the canopy of the trees. The difficulty of accessing these areas, as well as avoiding direct contact of herbicides with tree foliage, provides a substantial amount of nonmanaged plant material capable of rapidly reinfesting treated sites, thus making management efforts null and void. Herbicide application during the winter, when bald cypress sheds its leaves, may be an ideal time to manage S. molesta and minimize negative impacts on the nontarget tree. Therefore, the herbicides diquat, glyphosate, flumioxazin, and glyphosate+diquat were evaluated at one of the three application timings (December, January, or February) against S. molesta and immature bald cypress during the winter. All herbicide treatments, except diquat applied in February of year 1, reduced S. molesta biomass 40% to 100%. In addition, flumioxazin applications during December, January, and February provided ≥70% S. molesta control with little or no negative impacts to bald cypress health. A treatment by timing interaction revealed that trees exposed to flumioxazin did not result in a significant decrease in average leaf length when compared with reference trees 20 wk after bud break at any of the three application timings. In addition, bald cypress exposed to flumioxazin produced the highest probability of a refoliation pattern equivalent to the nontreated reference trees. Although complete tree mortality was not documented in either study, delayed and abnormal leaf formation, reduced leaf length, irregular canopy formation, or no negative effects were observed among herbicide-treated bald cypress. This research suggests that winter herbicide applications over the top of dormant bald cypress may be a practical management technique for controlling severe infestations of S. molesta.

Epiphytic lichens are increasingly included in forest biodiversity monitoring schemes, but most of the standardized guidelines consider only lichens colonizing a small part of tree trunks (1·0–1·5 m) and overlook other important microhabitats, such as fallen branches and stumps. In this paper, we present results of a small-scale pilot study to evaluate the possible advantage of including four distinct microhabitats in standardized procedures for assessing epiphytic lichen diversity. Trunk bases, trunks between 100 and 150 cm above the ground, stumps, and fallen branches were each sampled with a different standardized sampling method along a forest age gradient in temperate deciduous forests of the Caucasian region. Plot-level species richness was contrasted between the standardized sampling procedures of different substrata and a non-probabilistic floristic sampling. The interactions between sampling procedure and stand age were analysed using linear mixed models, and non-metric multidimensional scaling (NMDS) and multi-response permutation procedures (MRPP) were used for comparing species composition. Overall, 97 species were recorded, their richness increasing with increasing stand age. Results were consistent across the gradient of stand age and demonstrated that the adoption of standardized sampling procedures which include stumps and fallen branches in addition to tree trunks would increase the capability of maximizing species capture. This approach would allow researchers to evaluate lichen patterns by simultaneously considering the response of different communities sensitive to different stand-related factors. Despite the likelihood that a non-probabilistic floristic survey would give a more exhaustive picture of the plot-level lichen diversity, standardized sampling procedures that include tree trunks, fallen branches and stumps are likely to represent a reasonable trade-off between exhaustiveness and cost-effectiveness.

Five field experiments were conducted with snap bean (Phaseolus vulgaris L.) row spacings of 15, 25, 36, 46, and 91 cm, all of which were seeded at a constant density of 43 plants/m2. When weeds were allowed to emerge with the crop, row spacings of 15 to 36 cm suppressed weed growth by 18% compared to the conventional 91-cm row spacing. When weeds were controlled for the first half of the season, row spacings of 15 to 36 cm suppressed weed growth by 82% compared to the 91-cm row spacing. The effect of the 46-cm row spacing on weed growth was variable. Weed suppression by narrow rows was explained by a higher rate of snap bean canopy closure in narrow rows. Snap beans in row spacings of 15 to 46 cm produced similar yields and were higher by an average of 23% than yields produced by snap beans in 91 - cm rows.

Shoot growth and morphology of sicklepod responded to distance of sicklepod from the soybean row and relative time of emergence of crop and weed. Sicklepod was added to soybean as either uniform stands of 26 individuals m−2 or as widely spaced individuals. Sicklepod shoot height, number of main-stem nodes, number of primary branches, and shoot dry weight were decreased at 12 wk after emergence when plants were situated closer to a soybean row. Sicklepod that emerged 7 d later than soybean were shorter statured and had fewer main-stem nodes. Virtually all sicklepod overtopped the soybean, but proximity to the soybean row or later emergence reduced shoot dry weight up to 60%. A doubling in branches originating at lower main-stem nodes on sicklepod 25 cm from the row, compared to those in the row (upper branch numbers were unchanged), was associated with a 67% increase in leaves. Sixty to 90% of lower branches reached the upper canopy and thus contributed to the number of leaves above the soybean. Early-season effects of soybean interference on sicklepod reduced lower branches and, as a consequence, leaf production above the soybean late in the season, when sicklepod has the greatest impact on soybean yield.

Light regulates many facets of plant growth and development through the effects of quantity of total energy and of photons, spectral quality, duration, and photoperiod. Numerous techniques and types of equipment are available for quantifying light in plant canopies. The effect of total quantity of light on weed and crop productivity has been described for many cropping systems. Recent work has focused on other aspects of light, in particular, spectral distribution of light (quality), transient light (sunflecks), and plant adaptation to changing light environments. The altered spectral quality of light in a plant canopy affects plant growth and morphology, which in turn affect competition for light. Dynamic plant response to transient light is also important to canopy photosynthesis and productivity. Plant physiological and morphological adaptation to fluctuating light is another potential factor regulating weed/crop interactions. Current cropping practices such as using smother crops and narrow row spacing exploit plant light responses to promote crop growth and suppress weed growth. A better understanding of plant responses to light quality, transient light, and fluctuating light environments will lead to a better understanding of how to manipulate the light environment in crop canopies to improve weed management.

A fundamental component of modeling crop interference is the effect of understory photosynthetic photon flux density (PPFD) on weed architecture and growth. The effect of decreased PPFD on spaced redroot pigweed dry matter accumulation, distribution, and plant architecture was quantified by increasing corn density and delaying weed planting date. As canopy-transmitted PPFD declined, total dry matter accumulation decreased and relative dry matter distribution was greater to main-stem components than to branch components. Increased rectangularity in understory weed architecture was associated with a concomitant decrease in branch number. The proportion of leaf area and dry matter in the upper segment of the redroot pigweed increased as PPFD declined with increased corn density. Results suggest that changes in plant architecture, as influenced by canopy-transmitted PPFD, may be as important as those of total dry matter and leaf area when describing and predicting the effects of crop-weed interference.

New Super-High-Density (SHD) olive orchards designed for mechanical harvesting are increasing very rapidly in Spain. Most studies have focused in effectively removing the olive fruit, however the machine needs to put significant amount of energy on the canopy that could result in structural damage or extra stress on the trees. During harvest, a series of 3-axis accelerometers were installed on the tree structure in order to register vibration patterns. A LiDAR (Light Detection and Ranging) and a camera sensing device were also mounted on a tractor. Before and after harvest measurements showed significant differences in the LiDAR and image data. A fast estimate of the damage produced by an over-the-row harvester with contactless sensing could be useful information for adjusting the machine parameters in each olive grove automatically in the future.

The objective of this study was to compare the consistency and accuracy of visually estimated weed biomass and weed control data to data obtained through image analysis. Weed biomass and weed control were evaluated in soybean herbicide efficacy trials conducted at the University of Nebraska–Lincoln during 1992 and 1993. Measurements were based on visual estimates and on aerial photographs taken at a height of 3.5 m above the soil surface. Photographs were digitized and classified, producing pixel values for broadleaf weeds, grass weeds, soybean, and soil. Percent weed cover was calculated in relation to the crop canopy, based on the respective number of pixels per image. Visual and photographic ratings of weed biomass and of weed control were not closely correlated. In the first year the visual method discriminated between more treatments than the photographic method, but the opposite occurred in the second year. The photographic method predicted yield more closely than the visual estimates. We concluded that visual estimates were less consistent and more subject to observer bias than measurements obtained with the photographic method.

A 2-yr field study was conducted during 2007 and 2008 at Stoneville, MS, to determine the effect of twin-row (two rows 38 cm apart on 102-cm beds) and single-row (on 102-cm beds) patterns and glyphosate POST applications with and without fluometuron + S-metolachlor PRE on cotton canopy closure, weed control, and lint yield in two cultivars (‘DP117B2RF’, early maturity, hairy leaf; ‘DP164B2RF’, mid to full maturity, smooth leaf) under an irrigated environment. The experiment was conducted in a split–split plot arrangement of treatments in a randomized complete block design with row pattern as the main plot, cultivars as the subplot, and herbicide programs as the subsubplot. Cotton canopy closed 2 wk earlier in the twin-row pattern compared to the single-row pattern. Canopy closure was unaffected by cultivars and herbicide programs. Control of nine predominant weeds was sufficient (≥ 95%) to support cotton production. Total weed dry biomass was reduced by 35% in twin rows compared to the single-row pattern, 15% in DP117B2RF compared to DP164B2RF cultivar, and ≥ 97% with glyphosate early POST (EPOST), EPOST followed by (fb) mid-season POST (MPOST), EPOST fb MPOST fb late POST (LPOST) following PRE herbicides or three applications of glyphosate POST only without PRE herbicides compared to no herbicide. Cotton grown in twin-row pattern produced 6% higher lint yield than single-row cotton. Cultivar DP117B2RF produced 23% higher lint yield than cultivar DP164B2RF. Lint yields were higher with glyphosate EPOST fb MPOST, EPOST fb MPOST fb LPOST following PRE herbicides or three applications of glyphosate POST only without PRE herbicides (1,210 to 1,230 kg/ha) compared to glyphosate EPOST following PRE herbicides (1,130 kg/ha). These results demonstrated that cotton grown in twin-rows closed canopy early and produced higher lint yields than cotton grown in single-rows.

Epiphytes represent keystone resources for many arthropod and vertebrate species, however their ecology remains poorly explored, especially within the palaeotropics. Several recent studies have examined relationships between epiphyte richness and characteristics of local habitats, although these have all focused on neotropical forests. Here, we aim to determine whether predictors of neotropical epiphyte richness are consistent at a palaeotropical site. A total of 44 host trees (dbh range 25–288 cm) were sampled at two study sites on Buton Island, Indonesia. For each tree, epiphyte richness and seven variables relating to characteristics of the host tree and surrounding habitats were recorded: site (a proxy value for disturbance level and water availability), host above-ground biomass (agb), altitude, bark texture, exposure, emergence and crown area. Gaussian GLM analyses indicated that the percentage deviance explained in epiphyte richness per host was greatest for agb (20.9%), crown area (19.6%) and site (15.5%); similar to previous findings from the neotropics. Results therefore suggest that high epiphyte diversity within palaeotropical forests is most likely to be found in large tracts of undisturbed forest, supporting large, broad-crowned trees.

The Brazilian Amazon rain forest has lost c. 17% of its originally forested portion, due to deforestation and selective logging. Forest degradation caused by logging contributes to loss of animal species that require specialized habitats to survive, such as woodcreepers that inhabit understorey areas. Habitat associations of woodcreeper species can be important for identifying species that have restricted distribution and/or habitat specialization. Our study investigates the effects of spatial variation in forest structure and some landscape features (canopy openness, altitude, distance to stream and exploited basal area) on the abundance and composition of woodcreeper assemblage in selectively logged tropical forests in Southern Amazonia. We used mist-nets and points count to quantify the composition and abundance of woodcreepers in 32 plots in three sites. Plots were spatially arranged in PPBio LTER sites (long-term ecological research plots, systematically spaced at 1-km intervals) in Southern Amazonia. A total of 240 individuals (captured, observed and/or heard) belonging to 11 woodcreeper species were detected. Mantel tests showed that there is no spatial autocorrelation among woodcreeper assemblage and distance between plots. Altitude and canopy openness were significantly associated with the composition of the woodcreeper assemblage. Altitude was negatively associated with species richness, and the abundance of the two dominant species (Glyphorynchus spirurus and Xiphorhynchus elegans). The negative relationship with canopy openness suggests that woodcreeper assemblages that inhabit understorey are likely to be indirectly affected by selective logging which reduces canopy cover. The selective logging indirectly changes bird species assemblages, and depending on the intensity, may result in the local extinction of some insectivorous species. Short- and long-term studies addressing different intensities of selective logging are needed to determine the impacts on the bird species and forest structure.

Secondary hemiepiphytes rely on other plants (hosts) to grow vertically. After germinating on the forest floor, their seedlings search a host to ascend. We recorded information on survival, growth, reproduction and vegetative propagation of three Heteropsis species, to evaluate what drives their vital rates. We measured 700 individuals of each study species between 2007 and 2009 in the southern Colombian Amazon. A gradual increase in stem length, leaf size, number of roots and plagiotropic branches was found with increasing height of Heteropsis individuals on their hosts. Survival of leafless non-climbing seedlings was very low (28% annually); increasing substantially (84–94%) once the seedling had ascended a host. The three Heteropsis species presented slow height growth rates (c. 2–8 cm y−1) with large variation, while a substantial percentage of the stems (31–62%) did not grow or dried out. Vegetative propagation in Heteropsis may act as a dispersion-propagation strategy to find a suitable host and reach the canopy again after falling. The slow growth rates suggest that Heteropsis individuals that have reached the canopy are rather old. Once plants have reached the tree crowns, their longevity is largely determined by the survival of the host tree.

The vertical gradient of the community structure of epiphytic lichens in forest canopies was studied in southern Estonian coniferous forests. All lichen species on 15 Norway spruces and 15 Scots pines were recorded; age of trees ≥100 years. Species were sampled in height ranges on entire trees from the bottom to the top. The number of lichen species on pine trunks decreased with height from the ground, whereas the number of species on branches increased. There was no significant vertical change in the number of lichen species on spruce trunks; number of species on spruce branches was highest in mid canopy. The mean number of lichen species on a tree was 41 in spruces and 34 in pines; the mean number of species on the first 2 m was 14 in spruces and 12 in pines. According to the results, about two thirds of a tree's lichen species remain unrecorded if only the first 2 m near the ground are surveyed. Many lichen species were found only higher than 2 m, including several common species (e.g. Buellia griseovirens, Lecanora pulicaris, and Melanohalea exasperatula), but also some locally rather rare (Fellhanera subtilis, Micarea nitschkeana, Rinodina efflorescens) or red-listed ones (Evernia mesomorpha, Usnea barbata, U. fulvoreagens, U. substerilis, U. wasmuthii) and one new species for Estonia, Lecanora farinaria. There were also some species, such as Chaenotheca stemonea, Cladonia cenotea and C. norvegica, that were restricted to the lowest 2 m. The results indicate that canopy lichens form a significant part of lichen diversity in coniferous forests, and could add valuable information when estimating forest lichen diversity for conservation and other purposes.

Introduction. Optimising agricultural water use implies thecombination of physiological, technological and engineering techniques, especially thosefor continuously monitoring the water status of plants subjected to deficit irrigation. Amethodology to estimate water stress of young almond trees from thermal images wasdeveloped based on assessing the physiological status of almond crops under limitedwater-supply conditions. Materials and methods. Two irrigation treatmentswere tested during the maximum evapotranspirative demand period (214th to the 243rd day ofthe year) in an experimental almond [Prunus dulcis (Mill) D.A. Webb, cv.Guara] orchard: a low-frequency deficit irrigation (LFDI) treatment, irrigated accordingto the plant-water status, and a fully irrigated treatment (C100) at 100% of cropevapotranspiration. Daily canopy temperature at midday (TC) was measured with an infraredcamera, together with standard measurements of stem-water potential (ΨStem) and stomatalconductance (gS). The time course of these parameters and their relationships wereanalysed. Results and discussion. The time course of the parameters studiedshowed highly significant correlations among the differentials of canopy-air temperature(ΔT), ΨStem and gS. The methodological protocol for analysing thermal images allowed atime saving in processing information and additionally offered the possibility ofestimating the ΨStem and gS values. Conclusion. Our results confirm thatinfrared thermography is a suitable technique for assessing the crop-water status and canbe used as an important step towards automated plant-water stress management in almondorchards.

The impact of hurricanes on tropical forests has been well documented in recent decades, with hurricane disturbance hypothesized to be a leading contributor to maintenance of the high diversity of trees in lowland tropical rain forests (Frangi & Lugo 1991, Vandermeer et al. 2000). Hurricanes have a heterogeneous impact both on landscapes and tree species (Liu & Fearn 2000, Walker et al. 1996). Damage to trees can take many forms, from leaf loss to stem snapping to uprooting, and is variable across the landscape due to topography, wind speed, direction and tree density (Walker 1995).

We investigated the pollinator assemblage in Myristica dactyloides, a dioecious tree species occupying the intermediate canopy stratum of the mid- and high-elevation wet evergreen forests and endemic to Sri Lanka and the Western Ghats of India. We surveyed two populations and, in one of them, marked four male and three female trees for observations on floral display and insect foraging, and two female trees for experimental pollination. Yellow sticky traps were used to sample insects in the canopy during the flowering season of December 2007 in addition to direct observations of insect activity in 2006. Myristicaceae members from other tropical areas have been reported to be specialized to beetle pollination, but our observations provide evidence of a generalist pollination system in M. dactyloides, composed of small, diverse insects: thysanopterans (thrips), coleopterans (beetles), halictid bees and dipterans (syrphid and phorid flies). Quantifying floral display, we found that female inflorescences were smaller, offered no reward and attracted significantly fewer pollinators in comparison to male inflorescences. Fruit set was low and could be attributed to a 29% flower abscission and abortion of young fruits, but a reasonably high natural pollination efficiency combined with pollination experiments established that there was no pollination limitation in the study population.

Tropical rain forests harbour the most diverse plant and animal assemblages known to science, but our understanding of assemblage structure and species interactions is limited. Bats, as the only flying mammals, have the potential to exploit resources from all strata in forest communities. Thus, fruit-eating phyllostomid bats often have been categorized into canopy-, subcanopy- and understorey-foraging species, based largely upon the height at which they were most frequently captured. Here we challenge this classification and use stable carbon isotopes to assess foraging height of bat species at an Amazonian rain-forest site in Ecuador and at a Caribbean lowland rain-forest site in Costa Rica for comparison with data from mist-net captures. The proportion of the heavy stable carbon isotope 13C in relation to the lighter 12C isotope increases in plants from ground level to the canopy (0.12‰ m−1–0.18‰ m−1), and these differences in stable carbon isotope signatures are reflected in the body tissue of phytophagous bats. We used the stable carbon isotope ratio (δ13C) of wing tissue to estimate the foraging heights of 54 phyllostomid species in two Neotropical bat assemblages. Based on stable isotope data, phyllostomid species exploit food resources at all vertical strata of the forest. Capture height was not a reliable predictor of foraging height and suggests that bats most likely use lower strata to commute between foraging sites to avoid predators. Vertical stratification is likely to be a key factor promoting niche partitioning, thus promoting high local species richness in many tropical animal assemblages.