Rainforest Research Articles

Agricultural land use policies and landscape dynamics: Evidence from rainforest agroecological zone

Agricultural-land use policies play a crucial role in shaping agroecological landscapes globally. The evidence suggests that some of these policies tend to have undesired feedback/trade-offs, particularly about coastal resource use and conservation planning. The present study explores how agricultural policies influence land use/land cover (LULC) transition patterns in Ghana's Rain Forest Agroecological Zone (RFAZ). Landsat satellite images for 1991, 2008, and 2022 were acquired for the LULC mapping. Change detection and Intensity analysis were used to assess the pattern of land change. Also, documentary research processes were used to review and assess agricultural land use policies. The results showed that before rubber-related policy implementation, oil palm plantation was the dominant LULC type in the 1990 s. In the 1990 s and early 2000 s, there was a conscious government drive to leverage oil palm plantation development. This led to the growth in the size of oil palm plantations within the RFAZ landscape, considering the zone’s conducive natural environment. However, between 2008 and 2022, corresponding to the period of the increased promotion of rubber cultivation through the Outgrower project in the RFAZ, rubber plantations became the predominant land use, with an area of 11,763.81 ha in 2008 and 21,611.61 ha in 2022. The results from the LULC mapping and the intensity analysis showed that the Rubber Outgrowers Plantation Project (ROPP) and Norpalm Smallholder Scheme Project (NSSP) have degraded the natural cover through rubber and oil palm cultivation. The authors conclude that landscape dynamics, particularly in rainforest agroecological zones, represent a nexus challenge transforming policy adaptation's discursive context. The study recommends that agriculture and landscape policy/projects must have/take intermediary steps to address the feedback/trade-offs from well-intended initiatives. The study further suggests that management plans and strategies in the RFAZ should be consistent with the strict protection of forest reserves and water bodies.

Avian functional diversity retained in a tropical rainforest fragment after more than 120 years of turnover

Deforestation is linked to the increasing prevalence of small forest fragments worldwide and an associated loss in functional diversity. However, our long-term understanding on how biodiversity and functional roles respond in such isolated fragments is limited, especially in Southeast Asia. We compared the bird community in a small primary rainforest fragment in the Singapore Botanic Gardens, a UNESCO World Heritage Site, using historical records in 1898 and contemporary surveys conducted in 1998 and 2018–2021. Species composition was expectedly dissimilar between the 1898 and contemporary bird communities (50%), driven mostly by turnover (45.5%) rather than nestedness (4.5%). Despite the changes in community composition and species extirpations, both species richness and functional diversity were retained. Our results suggest that small forest fragments can form novel bird communities that are functionally similar to previous communities that inhabited the fragment, leading to the retention of functional diversity. Such functional redundancy may be encouraged through habitat restoration initiatives adjacent to fragmented forests.

Effects of subtle variation in forest canopy openness on cache pilferage and its implications for forest regeneration.

Scatter-hoarding rodents play important roles in plant regeneration and species coexistence in many forest ecosystems. Cache pilferage, the behavior of rodents seeking or relocating seeds cached by other individuals, is ubiquitous during the scatter-hoarding process. The effects of canopy openness on cache pilferage have received considerable attention, most of which have focused on the comparison between full canopy cover and completely open areas, such as forest gaps. However, little attention has been given to whether the subtle variation in forest canopy openness affects cache pilferage, although subtle variation in light environments exists in many forests, especially tropical and subtropical forests, where the overall canopy is large and the forest window is relatively small. Here, we directly tested these questions by simulating 400 artificial caches, each containing one seed from four selected tree species, in a subtropical forest in southwestern China. The overall canopy openness of the forest was relatively small (with a mean value of 11.1%), but subtle spatial variation still existed (ranging from 5.7% to 19.5%). Overall, caches with lower canopy openness were more likely to be pilfered and removed faster, although not all species showed the same pattern. Our study highlights that subtle variation in forest canopy openness, even in a closed primary forest, has significant effects on cache pilferage by rodents, which may influence the following seed germination and forest regeneration processes. Additionally, seedling species composition may further be altered because the canopy effects on cache pilferage are species-specific.

Light Environment and Photosynthetic Capacities of Leaves at Different Locations within Eggplant Canopies in a Greenhouse in Ontario, Canada

To effectively manage crop production in a greenhouse, it is essential to understand the natural light environment and physiological responses of the plants to light. This study investigated the dynamics of photosynthetic photon flux densities (PPFD) and light quality within the canopies of greenhouse-grown eggplant (Solanum melongena) and the photosynthetic capacities of leaves at different locations within the canopies. The light environment was quantified at 0.2-m intervals within (intra-canopy) and adjacent to (extra-canopy) the crop canopy on both sunny and cloudy days within a commercial greenhouse located in Leamington, Ontario, Canada. Our results indicated a linear decline in extra-canopy PPFD on both sunny and cloudy days, but an exponential decrease in intra-canopy PPFD. The intra-canopy PPFD decreased by 91% and 76% between 0 m and 0.4 m from the canopy apex on sunny and cloudy days, respectively. The lower canopy (0.6–1.2 m) light spectrum consisted largely of far-red light, equal amounts of red light and green light, with a lower percentage of blue light. Parameters derived from leaf-level light response curves indicated that the light-saturated net carbon exchange rate, light saturation point, and light compensation point decreased as the distance from canopy apex increased, whereas quantum yield was unaffected. Thus, leaves in the lower canopy were less efficient at using high PPFD, but they displayed no deterioration of photosynthetic machinery. Based solely on photosynthetic capabilities, leaves between 0 and 1.0 m from the canopy apex should not be removed to decrease the total plant sink strength.

Trap Height Affects Capture of the Pecan Nut Casebearer (Lepidoptera: Pyralidae)1

Abstract The pecan nut casebearer, Acrobasis nuxvorella Neunzig (Lepidoptera: Pyralidae), is a monophagous pest attacking pecan, Carya illinoinensis (Wangenh.) Koch. Pheromone traps attractive to adult males are used to monitor this pest in orchards by placing them in the lower canopy. However, some insects exhibit vertical stratification in tree canopies as does occur for some beneficial and pest species associated with pecan. The objective of this study was to assess vertical stratification of the pecan nut casebearer in the canopy of tall pecan trees when sampling with pheromone traps. Traps were placed at three heights in orchards (1.5, 7.6, and 13.7 m) above ground. In one experiment, only one trap was placed at one of the three heights at a tree. In the other experiment, three traps, one at each height, were placed in the canopy of the same tree. Results from both experiments reveal that the pecan nut casebearer does stratify within the pecan canopy. Significantly more moths were captured in the highest trap than in the traps at the other heights. These results provide information useful for developing pecan nut casebearer management strategies such as mating disruption in pecan orchards with tall trees.

Evaluation of chemical attributes of soils: definition of management zones in silvipastoral system

Soil chemical analysis is a fundamental to achieve optimal cultivation conditions in a productive silvopastoral system, essential for the planning and management of this activity. The objective of this research is to map the spatial distribution of nutrients in the soil in a 5-year-old silvopastoral system composed of brachiaria-brizantha and jacarandá-da-bahia, and to analyze the effect of tree density and canopy on nutrient levels. The study was conducted at the experimental area of the Capixaba Institute for Research, Technical Assistance, and Rural Extension (INCAPER) in the district of Pacotuba, ES. The delimitation of the work area was done using geographic information systems, to create a regular grid of points to enable systematic soil sampling. A total of 75 disturbed soil samples were collected at depths of 0-0.10 m to obtain quantitative soil nutrient data. High-quality images obtained using a remotely piloted aircraft (RPA) allowed for the overlay of soil nutrient data, pasture data, forest inventory data, and sample plot data to assist in comparative analyses. This enabled identification of the areas with lower canopy development, particularly in the northeast portion. By cross-referencing the spatialized soil nutrient data with the data obtained through RPA, it was possible to correlate them with the lower or higher development of the system. The use of RPA, together with a georeferenced database, proved to be an innovative and powerful tool to support decision-making, allowing for the monitoring of system evolution and serving as a basis for evaluating the relationship between chemical elements and tree canopies. Keywords: geostatistics, precision agriculture, soil nutrients.

GROWTH ACCELERATION AND GALANTHAMINE CONTENT OF HIPPEASTRUM PAPILIO PLANTS GROWN ON HYDROPONIC SYSTEMS

Hippeastrum papilio (Ravenna) Van Scheepen (Amaryllidaceae) is an endangered endemic species from the rainforests of Brazil. It is not only an attractive ornamental plant, but the species with the highest content of the valuable alkaloid galanthaminе used for treatment of Alzheimer’s disease. The rapid propagation of the plants is crucial for biomass production as an alternative plant raw material for industrial galanthamine extraction. The aim of the present study was to accelerate the growth of H. papilio bulbs using two different hydroponic systems and to evaluate their effectiveness, as well as to determine the galanthamine content in the leaves. Differences in seedlings’ growth on Flood & Drain hydroponic system, on Cutting board hydroponic system, and in soil substrate as a control were significant (P<0.001, Anova single factor). Best results were obtained on the Cutting board hydroponic system where plant weight increased an average of 59.1 ± 24.0 times while the lowest growth was in the control, with an average weight increase of 11.1 ± 4.7 times. One month after adaptation of plants to soil substrate they were analysed by GC-MS. Galanthamine was the main alkaloid in the leaves of plants from all variants, and its content varied between 0.66% and 0.86%, which was commensurable with that of the native plants. Feasibility of soilless cultivation of in vitro propagated H. papilio bulblets was also proven.

Legacy effects of premature defoliation in response to an extreme drought event modulate phytochemical profiles with subtle consequences for leaf herbivory in European beech.

Extreme droughts can have long-lasting effects on forest community dynamics and species interactions. Yet, our understanding of how drought legacy modulates ecological relationships is just unfolding. We tested the hypothesis that leaf chemistry and herbivory show long-term responses to premature defoliation caused by an extreme drought event in European beech (Fagus sylvatica L.). For two consecutive years after the extreme European summer drought in 2018, we collected leaves from the upper and lower canopy of adjacently growing drought-stressed and unstressed trees. Leaf chemistry was analyzed and leaf damage by different herbivore-feeding guilds was quantified. We found thatdrought had lasting impacts on leaf nutrients and on specialized metabolomic profiles. However, drought did not affect the primary metabolome. Drought-related phytochemical changes affected damage of leaf-chewing herbivores whereas damage caused by other herbivore-feeding guilds was largely unaffected. Drought legacy effects on phytochemistry and herbivory were often weaker than between-year or between-canopy strata variability. Our findings suggest that a single extreme drought event bears the potential to long-lastingly affect tree-herbivore interactions. Drought legacy effects likely become more important in modulating tree-herbivore interactions since drought frequency and severity are projected to globally increase in the coming decades.

Microplastics alter the leaf litter breakdown rates and the decomposer community in subtropical lentic microhabitats

Microplastics, pervasive pollutants in aquatic environments, have been primarily studied for their impact on marine ecosystems. However, their effects on freshwater systems, particularly in forested phytotelmata habitats, remain understudied in Subtropical systems. This research examines the influence of varying microplastic concentrations (0.0, 200, 2,000, 20,000, and 200,000 ppm) on leaf litter breakdown of Inga vera (in bags of 10 and 0.05 mm mesh) and the naturally associated invertebrate community occurring in forested phytotelmata. The study employs an experimental design with microplastic concentration treatments in artificial microcosms (buckets with 800 mL of rainwater) arranged in an area of Atlantic Rain Forest native vegetation of Subtropical systems. The results indicate that elevated concentrations of microplastics may enhance leaf litter breakdown (6–8%), irrespective of the bag mesh, attributed to heightened decomposer activity and biofilm formation. Consequently, this contributes to increased invertebrate richness (33–37%) and greater shredder abundance (21–37%). Indicator analysis revealed that Culicidae, Stratiomyidae, Chironomidae, Empididae, Planorbidae, and Ceratopogonidae were indicative of some microplastic concentrations. These findings underscore the significance of accounting for microplastics when evaluating the taxonomic and trophic characteristics of invertebrate communities, as well as the leaf breakdown process in Subtropical systems.

Health Benefits of Airborne Terpenoids and Aeroanions: Insights from Thematic Review of Chinese-Language Research on Forest Sensory Experiences

Most research on air chemistry and human health has focused on negative consequences of air pollution from cities, rural dust, mining, or industrial sites. Research on nature tourism and nature therapy, in contrast, focuses on positive benefits of air quality for physical and mental health, e.g., via “clean air clean water” holidays. Aeroanions and terpenoids in forests have received particular attention, especially in China, Japan, and Korea. We review and analyse several hundred articles published in English and Chinese. With a few recent exceptions, English-language research has tested indoor negative ion generators, and concluded that they have no measurable health benefit. It has tested terpenoids in indoor aroma marketing. Chinese-language research, in contrast, has analysed fine-scale components of outdoor environments that affect concentrations of aeroanions and terpenoids: ecosystem, latitude, altitude, temperature, proximity to water, and individual plant species. Historically, health outcomes have been taken for granted, with little rigorous testing. Air quality research has shown that aeroanions can become attached to fine water droplets, e.g., after rain in forests, or in mists produced locally by waterfalls. We hypothesise that the health benefits of aeroanions in natural environments may arise through the scavenging of airborne particulates by negatively charged mists, creating especially clean, dust-free air. We propose that this particularly clean-tasting air, contrasting strongly with polluted urban air, creates positive effects on human mental health and perhaps, also on pulmonary physical health. Mechanisms and outcomes remain to be tested. We also propose testing psychological health effects of airborne terpenoid scents from forest trees.

Bark thickness and related parameters of tree species along an elevation transect leading to treeline in Central Himalaya.

Since treelines are generally fire-free, the trees growing there are expected to have thin bark, unless adaptation to other factors than fire results in the selection of a thick bark. Related to this is also higher proportional investment in inner bark in such an environment of infrequent fire. This study has considered stem bark thickness both in absolute and relative terms and also in the frame of the composition of outer and inner bark components of 20 tree species along an elevation transect (2100-3300m) in high ranges of the Central Himalaya leading to treelines. The study species varied from 2.1 to 16.2mm for total bark thickness and from 1.2 to 18.85% for relative bark thickness. The average absolute total bark thickness across the tree species decreased with elevation from forest to treeline, both when trees of all diameters (10.2 ± 0.84mm for forest and 6.9 ± 1.79mm for treeline) and those of the same stem diameter range (18-20m) were compared (9.10 ± 1.30mm for forest species and 6.38 ± 1.31mm for treeline species). Nevertheless, the treeline bark thickness was similar to those of several forest communities considered to have comparatively thick bark. Like many other biological structures, bark carries out multiple functions; therefore, its thickness could be affected by more than one environmental factor. We suggest that the requirement of mechanical resistance to the snowfall, rainstorms, wind and adaptation to a high sunlight and UV radiations or storage of water, and non-structural carbohydrates could affect total, outer and inner bark thickness. Studies on these aspects in similar ecosystems may help understand the multi-functional attributes of the bark. For trees of comparable sizes (trees with 18-20cm diameter at breast height) treeline species also had lower relative bark thickness (< 6%) than trees of forest below it (> 7%). The median proportion of inner bark of the total bark (70.5%) for our 20 species was more than that for savannas (~ 50%), exposed to frequent fire regime and similar to those of in cool sclerophyllous forests and temperate rain forests where fire return time is > 100years. However, it was lower than the inner bark proportion reported for tropical rain forests. To conclude, in spite of a fire-free environment, the Himalayan treeline and adjoining forest species show mixed bark characters.

Photosynthetic capacity and assimilate transport of the lower canopy influence maize yield under high planting density.

Photosynthesis is a major trait of interest for the development of high-yield crop plants. However, little is known about the effects of high-density planting on photosynthetic responses at the whole-canopy level. Using the high-yielding maize (Zea mays L.) cultivars "LY66," "MC670," and "JK968," we conducted a 2-yr field experiment to assess ear development in addition to leaf characteristics and photosynthetic parameters in each canopy layer at 4 planting densities. Increased planting density promoted high grain yield and population-scale biomass accumulation despite reduced per-plant productivity. MC670 had the strongest adaptability to high-density planting conditions. A physiological analysis showed that increased planting density primarily led to decreases in the single-leaf area above the ear for LY66 and MC670 and below the ear for JK968. Furthermore, high planting density decreased chlorophyll content and the photosynthetic rate due to decreased canopy transmission, leading to severe decreases in single-plant biomass accumulation in the lower canopy. Moreover, increased planting density improved presilking biomass transfer, especially in the lower canopy. The yield showed significant positive relationships with photosynthesis and biomass in the lower canopy, demonstrating the important contributions of these leaves to grain yield under dense planting conditions. Increased planting density led to retarded ear development as a consequence of reduced glucose and fructose contents in the ears, indicating reductions in sugar transport that were associated with limited sink organ development, reduced kernel number, and yield loss. Overall, these findings highlighted the photosynthetic capacities of the lower canopy as promising targets for improving maize yield under dense planting conditions.

The Effects of Several Forms of Leaf Area Management and Different canopy heights with vertical shoot positioning on Berry Ripening and Wine Quality

The goal of this research was to investigate different canopy heights and canopy management approaches in VSP-trained vineyards on the production of sugar and other substances present in berries and must, as well as on the resulting wine quality. Two sites, one high vigor and one low vigor, were selected for this study, with the following treatments tested: [1] ‘control’, shoots were topped according to standard practices; [2] ‘without lateral shoots’, all lateral shoots were removed; [3] ‘low canopy’, the canopy was shortened to 50 cm below the height of the ‘control’; [4] ‘twisted shoots’, shoots were not hedged, but instead were horizontally twisted along the upper wires. The ‘low canopy’ treatment revealed little effect on grape ripening parameters, especially in the low vigor trials. Upon sensory analysis, the quality of wine derived from this treatment did not score higher than the control, but rather repeatedly lower. Furthermore, ‘low canopy’ wines exhibited atypical aging notes, and in certain vintages more Berry shrivel was observed during the vegetative season. The ‘twisted shoots’ treatment displayed repeatedly higher YAN values in the must, especially in vineyards with higher vigor, which led to an increase in potential vine fertility. Thus, shortening the canopy was not found to be a suitable technique to delay ripening or improve wine quality.

Some Observations from a Summer Trip to Alaska

Last summer my wife and I went to Alaska for a couple of weeks. In my nearly 40 years of work with the U.S. Fish and Wildlife Service I never had the opportunity to experience Alaska’s wetlands, so I had to do it in retirement — one item on my bucket list. We started our trip in Anchorage and our first stop with the rental car was Potter Marsh which has a great boardwalk system traversing the marsh. To our surprise after walking just 100 yards, we saw a moose feeding in the shallow water...what a sight at our first stop. We then went to Seward and along the way stopped at the Alaska Wildlife Conservation Center and Exit Glacier. When back in Anchorage we stopped at 49th State Brewing where I had two pints of a delicious imperial stout — “Candy Bar” — brewed with peanuts, chocolate, and caramel...perfect for my sweet tooth (sorry but the beer was just so good I have to give it a shout-out). We also visited a high school classmate who was a teacher in Anchorage and spent a day in Talkeetna where we spoke with Aurora Dora, a local photographer who has captured some amazing images of the Aurora Borealis (check out images on her website: https://auroradora.com/). Here we also sampled some birch syrup made from White or Paper Birch (Betula papyrifera var. humilis and B. neoalaskana). On Day 3 we began our Princess land-sea cruise tour as we headed north to Denali for a couple of days and then took the scenic train to Whittier (great views of Alaska’s wetlands on the way, despite the rain) and then to various ports via ship. I was hoping to see some bears in Denali and other places, but the salmon were not yet running, so bears were out of sight although I did see one running across a meadow at some distance. I also saw a few along with other animals common to the state at the Alaska Wildlife Conservation Center where they rescue injured/orphaned wildlife. Some high points of the trip were seeing Denali in all its glory, a female moose with calf at Horseshoe Lake, wildflowers in bloom along the Savage River Trail and the Savage Alpine Trail (exhausting but great time for wildflower photography), a hike across a local bog at Hoonah (Icy Strait Point), a hike through a temperate rain forest (Tongass National Forest) to Mendenhall Glacier, and seeing Humpback Whales (Megaptera novaeangliae) bubblenet feeding in Auke Bay, plus views of a few other glaciers and whales during the cruise. If you don’t know what bubble-net feeding is ... check out this website: https:// www.youtube.com/watch?v=z00G0RxeSP0. There’s still more to see in Alaska, so we’ll probably be heading back in late summer 2025 to travel inland. Here’s some mostly wetland-centric images from the trip.

The Combination of High-Light Efficiency Pruning and Mulching Improves Fruit Quality and Uneven Maturation at Harvest in Camellia oleifera

Camellia oleifera Abel is rich in oil, which is beneficial to human health. Seasonal drought and uneven canopy microclimate distributions result in low yields and picking efficiencies. To reveal the features of fruit development in the canopy and evaluate the impact of pruning on the canopy microclimate and fruit parameters, a field experiment was carried out in Zhuzhou, Hunan. The C. oleifera tree canopy was divided into four positions: inside the upper canopy (UI); inside the lower canopy (LI); outside the upper canopy (UO); and outside the lower canopy (LO). A combination of high-light efficiency tree pruning and mulching with camellia shells and weedproof film (CPM) was tested and compared with mulching (M). Compared with temperature and humidity, canopy light intensity is a key climate factor that affects the development of Camellia oleifera fruits. CPM improved the canopy light distribution and increased the light intensity inside the canopy of C. oleifera. There was no significant difference in the fruit cracking rate among the four canopy positions in the CPM treatment, which indicated that the fruit maturation period tended to be consistent across the canopy positions. Treatment with CPM resulted in 24.14% and 4.11% greater yield and oil content ratios, respectively, than the treatment with M. The fresh weight of the fruits from LO was the lowest, and the fatty acid accumulation was the lowest due to the poor light availability. CMP increased fruit quality, particularly in LI, which was 41.92%, 36.36%, 13.21%, and 12.79% greater in terms of fresh weight, yield, fresh seed rate, and oil content, respectively, than M. Unfortunately, there was no discernible difference in fatty acid components between CPM and M. Our research suggested that pruning combined with the mulching of organic material is an effective way to alleviate seasonal drought and uneven fruit maturation in C. oleifera trees, further increasing yield and fruit quality.

Canopy cover and microtopography control precipitation-enhanced thaw of ecosystem-protected permafrost

Northern high-latitudes are projected to get warmer and wetter, which will affect rates of permafrost thaw and mechanisms by which thaw occurs. To better understand the impact of rain, as well as other factors such as snow depth, canopy cover, and microtopography, we instrumented a degrading permafrost plateau in south-central Alaska with high-resolution soil temperature sensors. The site contains ecosystem-protected permafrost, which persists in unfavorable climates due to favorable ecologic conditions. Our study (2020–2022) captured three of the snowiest years and three of the four wettest years since the site was first studied in 2015. Average thaw rates along an across-site transect increased nine-fold from 6 ± 5 cm yr−1 (2015–2020) to 56 ± 12 cm yr−1 (2020–2022). This thaw was not uniform. Hummock locations, residing on topographic high points with relatively dense canopy, experienced only 8 ± 9 cm yr−1 of thaw, on average. Hollows, topographic low points with low canopy cover, and transition locations, which had canopy cover and elevation between hummocks and hollows, thawed 44 ± 6 cm yr−1 and 39 ± 13 cm yr−1, respectively. Mechanisms of thaw differed between these locations. Hollows had high warm-season soil moisture, which increased thermal conductivity, and deep cold-season snow coverage, which insulated soil. Transition locations thawed primarily due to thermal energy transported through subsurface taliks during individual rain events. Most increases in depth to permafrost occurred below the ∼45 cm thickness seasonally frozen layer, and therefore, expanded existing site taliks. Results highlight the importance of canopy cover and microtopography in controlling soil thermal inputs, the ability of subsurface runoff from individual rain events to trigger warming and thaw, and the acceleration of thaw caused by consecutive wet and snowy years. As northern high-latitudes become warmer and wetter, and weather events become more extreme, the importance of these controls on soil warming and thaw is likely to increase.

Rehabilitation of tropical urban streams improves their structure and functioning

Urban streams are affected by a complex combination of stressors, which modify physical habitat structure, flow regime, water quality, biological community composition, and ecosystem processes and services, thereby altering ecosystem structure and functioning. Rehabilitation projects have been undertaken in several countries to rehabilitate urban streams. However, stream rehabilitation is still rarely reported for neotropical regions. In addition, most studies focus on structural aspects, such as water quality, sediment control, and flood events, without considering ecosystem function indicators. Here, we evaluated the structure and functioning of three 15-y old rehabilitated urban stream sites in comparison with three stream sites in the best available ecological condition (reference), three sites with moderate habitat alteration, and three severely degraded sites. Compared to degraded streams, rehabilitated streams had higher habitat diversity, sensitive macroinvertebrate taxa richness, and biotic index scores, and lower biochemical oxygen demand, primary production, sediment deposition, and siltation. However, rehabilitated streams had higher primary production than moderate and reference streams, and lower canopy cover, habitat diversity, sensitive macroinvertebrate taxa richness, and biotic index scores than reference streams. These results indicate that rehabilitated streams have better structural and functional condition than degraded streams, but do not strongly differ from moderately altered streams, nor have they reached reference stream condition. Nonetheless, we conclude that rehabilitation is effective in removing streams from a degraded state by improving ecosystem structure and functioning. Furthermore, the combined use of functional and structural indicators facilitated an integrative assessment of stream ecological condition and distinguished stream conditions beyond those based on water quality indicators.

Freezing and Mechanical Failure of a Habitat-Forming Kelp in the Rocky Intertidal Zone.

Kelp and other habitat-forming seaweeds in the intertidal zone are exposed to a suite of environmental factors, including temperature and hydrodynamic forces, that can influence their growth, survival, and ecological function. Relatively little is known about the interactive effect of temperature and hydrodynamic forces on kelp, especially the effect of cold stress on biomechanical resistance to hydrodynamic forces. We used the intertidal kelp Egregia menziesii to investigate how freezing in air during a low tide changes the kelp's resistance to breaking from hydrodynamic forces. We conducted a laboratory experiment to test how short-term freezing, mimicking a brief low-tide freezing event, affected the kelp's mechanical properties. We also characterized daily minimum winter temperatures in an intertidal E. menziesii population on San Juan Island, WA, near the center of the species' geographic range. In the laboratory, acute freezing events decreased the strength and toughness of kelp tissue by 8-20% (change in medians). During low tides in the field, we documented sub-zero temperatures, snow, and low canopy cover (compared to summer surveys). These results suggest that freezing can contribute to frond breakage and decreased canopy cover in intertidal kelp. Further work is needed to understand whether freezing and the biomechanical performance in cold temperatures influence the fitness and ecological function of kelp and whether this will change as winter conditions, such as freezing events and storms, change in frequency and intensity.

Excastra albopilosa, a remarkable new genus and species of Lamiinae (Insecta: Coleoptera: Cerambycidae) from southeastern Queensland, Australia

A new genus and species of Cerambycidae from the subfamily Lamiinae is described from subtropical rainforest in southeastern Queensland, Australia. Excastra albopilosa gen. et sp. nov. is easily distinguished from all other Australian Lamiinae by its dense covering of short adpressed white setae and the long erect white setae forming twisted spires. A modification to the key to Australian Lamiinae genera is provided to accommodate Excastra gen. nov.

Cuticular Hydrocarbon Profiles of Himalayan Bumble Bees (Hymenoptera: Bombus Latreille) are Species-Specific and Show Elevational Variation.

Bumble bees are important pollinators in natural environments and agricultural farmlands, and they are in particular adapted to harsh environments like high mountain habitats. In these environments, animals are exposed to low temperature and face the risk of desiccation. The Eastern Himalayas are one of the recognized biodiversity hotspots worldwide. The area covers subtropical rainforest with warm temperature and high precipitation as well as high mountain ranges with peaks reaching up to 7,000m, shaping a diverse floral and faunal community at the different elevational zones. To identify possible adaptation strategies, we investigated the cuticular hydrocarbon profiles of four bumble bee species occurring at different elevational ranges in Arunachal Pradesh, the northeastern most state in India. At 17 locations along an elevational gradient, we collected workers of two species from lower elevations (B. albopleuralis and B. breviceps; ~ 100m - 3,000m asl) and two species from higher elevations (B. prshewalskyi and B. mirus; ~ 2,800m - 4,500m asl). The CHC profiles of all four species showed a significant degree of variation in the composition of hydrocarbons, indicating species specificity. We also found clear correlation with elevation. The weighted mean chain length of the hydrocarbons significantly differed between the low and high elevation species, and the proportion of saturated hydrocarbons in CHC profiles significantly increased with the elevational range of the bumble bee species. Our results indicate that bumble bees living at high elevations reduce the risk of water loss by adapting their CHC composition on their cuticle, a phenomenon that has also been found in other insects like ants and fruit flies.