Forest Transect Research Articles

Nesting resource availability for cavity adopter birds in a tropical dry forest of Central Mexico

Nesting resources for cavity-adopter birds commonly have spatial aggregation patterns within tropical dry forests. Spatial aggregation occurs because large trees, carrying large cavities, are restricted within small semideciduous forest areas. In contrast, deciduous forests occupy most of the coverage with smaller trees and cavities. Consequently, semideciduous forest loss could imperil cavity-adopter birds with large bodies. To test this hypothesis, we performed an intensive search in a tropical dry forest in Central-Mexico. We survey five 0.2 Ha transects in both deciduous and semideciduous forest, totalizing a survey of 2 Ha. There were no differences in resource density between deciduous (4 ± 6.51 cavities/Ha) and semideciduous forest (11 ± 6.51 cavities/Ha). However, semideciduous forest cavities had wider entrances and were in larger trees. Besides, 90% of nesting resources for birds with bodies > 6 cm were restricted within the semideciduous forest, including Megascops seductus, an endemic owl, and Ara militaris, a threatened macaw. Bird-excavated cavities were associated with deciduous forest and Pachycereus weberi cacti. In contrast, decay cavities were associated with semideciduous forest and Enterolobium cyclocarpum trees. Our results suggest that the conservation of large-bodied cavity-adopter birds within dry forest depends on semideciduous forest coverage.

Forest terrains influence walking kinematics among indigenous Tsimane of the Bolivian Amazon.

Laboratory-based studies indicate that a major evolutionary advantage of bipedalism is enabling humans to walk with relatively low energy expenditure. However, such studies typically record subjects walking on even surfaces or treadmills that do not represent the irregular terrains our species encounters in natural environments. To date, few studies have quantified walking kinematics on natural terrains. Here we used high-speed video to record marker-based kinematics of 21 individuals from a Tsimane forager-horticulturalist community in the Bolivian Amazon walking on three different terrains: a dirt field, a forest trail and an unbroken forest transect. Compared with the field, in the unbroken forest participants contacted the ground with more protracted legs and flatter foot postures, had more inclined trunks, more flexed hips and knees, and raised their feet higher during leg swing. In contrast, kinematics were generally similar between trail and field walking. These results provide preliminary support for the idea that irregular natural surfaces like those in forests cause humans to alter their walking kinematics, such that travel in these environments could be more energetically expensive than would be assumed from laboratory-based data. These findings have important implications for the evolutionary energetics of human foraging in environments with challenging terrains.

Soil microbial respiration in forest ecosystems along a north-south transect of eastern China: Evidence from laboratory experiments

Soil microbial respiration (MR) is a key process controlling the soil-atmosphere CO2 flux, and is widely studied at individual sites. Yet its spatial variation and underlying mechanism at larger spatial scales are still poorly understood, limiting our estimates of the carbon cycle in terrestrial ecosystems and its feedbacks to climate change. Here, a novel incubation experiment based on the mean annual temperature of soil origin sites along a 4,200 km north–south forest transect of eastern China was conducted to investigate the spatial variations in MR. MR showed a hump-shaped relationship with latitude and peaked around 32° N, which coincided exactly with the ecotone of subtropical and temperate forests. Climate, soil physicochemical and microbial traits explained 56.1% of the total variations in MR across the transect, whereas explained 77.4% and 34.6% in tropical and subtropical versus temperate region, respectively. Soil physicochemical properties were consistently more important in controlling the MR's variation than other variables. Specifically, soil organic carbon was the most important factor in regulating the MR's variation across the transect, whereas its significance decreased when scaling down to tropical and subtropical regions. The mean annual temperature turned into the best indicator of MR in tropical and subtropical forests, whereas the combination of soil organic carbon with total nitrogen concentrations primarily regulated the variations in MR in temperate region. Collectively, our study showed a non-linear latitudinal pattern of soil MR and revealed the diverged controlling factors and mechanisms of MR in different climatic regions. These findings can potentially improve our capacity to predict the soil CO2 flux in Earth system models and the feedbacks to climate change.

Potential gross nitrogen mineralization and its linkage with microbial respiration along a forest transect in eastern China

Nitrogen (N) mineralization in soils generally controls biological N availability in terrestrial ecosystems. As the pivotal first step in the overall N mineralization process, gross N mineralization (GNM, defined as the production of ammonium from microbial mineralization of organic N) is inherently coupled with microbial mineralization of soil organic carbon (C) which is commonly referred to as microbial respiration (MR), and that has often been used as a proxy of C availability. However, the pattern of GNM and its underlying mechanisms at a regional scale, and its linkage with MR remain unclear. By analyzing 100 soil samples collected across different forest types along a 3800 km long north-south transect in eastern China, we simultaneously measured the potential GNM using a 15N pool dilution method and MR using a dynamic CO2 trapping technique. We conducted a structural equation model (SEM) to examine the interactive effects of climate, soil pH, microbial substrate availability, and microbial biomass on potential GNM along the forest transect. Furthermore, we conducted a non-linear regression analysis between potential GNM and MR. We found that both potential GNM and MR varied largely, from 0.55 to 16.14 mg N kg−1 soil d−1 and from 3.64 to 24.30 mg C kg−1 soil d−1, respectively, but were not significantly affected by forest type. The SEM analysis showed that 51% of the variation in potential GNM was explained, with microbial substrate availability being the most important influencing factor. There was a positive non-linear relationship between potential GNM and MR (R2 = 0.52, P < 0.0001). Notably, MR alone exerted a comparable role in explaining the variation in potential GNM compared to the interactive effects between multiple factors used in the SEM. Our findings confirm the dominant control of C availability to microbes on potential GNM, and necessitate the incorporation of MR for better modeling GNM in forest soils.

THE AMPHIBIANS AND REPTILES OF RAWA AOPA WATUMOHAI NATIONAL PARK, SOUTHEAST SULAWESI

Rawa Aopa Watumohai National Park (105.194 ha) in Southeast Sulawesi is one of the important conservation areas in Wallacea. This study aimed to measure the diversity of herpetofauna, relative abundance and community similarity in four different habitats. Survey were conducted in January-April 2018 using Visual Encounter Survey (VES) based on time and transects in savanna, riparian, lowland forest, and mangrove. Forty-two species from 17 families were found consisting of 10 species of amphibians and 32 species of reptiles, in which 9 species are endemic i.e. Papurana celebensis and Draco beccarii. The highest diversity (H’) and evenness (E) indexes was found in lowland forest (H’ = 2.497, E = 0.555). The most abundant amphibian was Limnonectes modestus with 85 individuals (23.8%), while the most abundant reptile was Crocodylus porosus with 24 individuals (6.7%). The similarity of communities between the four habitats was low (&lt;0.5), indicating that most species are specialists on particular habitats. Although diversity was relatively low in Rawa Aopa Watumohai National Park, high endemism warrants ongoing efforts to conserve amphibians and reptiles in this national park. &#x0D; Key words: herpetofauna diversity, Indonesia, lowland forest, national park, Sulawesi

Interactive effects of elevation and newly paved road on avian community composition in a scientific reserve, Bioko Island, Equatorial Guinea

AbstractUnderstanding interactive effects between anthropogenic disturbance and abiotic factors on species turnover can help to identify and prioritize conservation of potentially vulnerable tropical bird communities. We investigated the potential factors influencing avian understory community composition along with a recently constructed road across three elevations (300, 800, and 1200 m), each with two sampling sites (road edge vs. interior forest), over a four‐year period on Bioko Island, Equatorial Guinea. Insectivorous species were the most abundant guild‐sampled accounting for 55% of total species diversity within the dataset followed by frequent mixed‐flock followers (48%). Habitat associated with elevation was the most significant factor influencing the composition of avian communities. Additionally, we identified species with clear statistical associations for each elevation: the yellow‐lored bristlebill (Bleda notatus), olive sunbird (Cyanomitra obscura), and white‐tailed warbler (Poliolias lopezi). We found evidence for significant community differences between the disturbance edge and interior forest transects at 300 m only. Likewise, understory insectivores were found at higher numbers within the interior forest transect at this elevation. Based on the data presented here, we suggest low elevation avian understory insectivores should be considered focal species for future assessment studies in this area. Furthermore, since many traditional protected areas focus on upland habitat containing high species endemism, our findings emphasize the importance of equally conserving lowland elevations as they may house commonly overlooked, yet important and diverse segments of the bird community.Abstract in Spanish is available with online material.

Functional redundancy of Amazonian dung beetles confers community‐level resistance to primary forest disturbance

AbstractTropical forest biodiversity is being threatened by human activities, and species losses during forest disturbance can compromise important ecosystem functions and services. We assessed how species losses due to tropical forest disturbance affect community functional structure, using Amazonian dung beetles as a model group. We collected empirical data from 106 forest transects and used simulated extinction scenarios to determine how species loss influences community structure at regional and local scales. Although functional and taxonomic community metrics were largely unaffected by primary forest disturbance, they differed markedly between primary and secondary forests. However, our extinction scenarios demonstrated scale‐dependence of species losses, whereby functional structure only eroded with species extinction at the local scale. Hence, we extend the spatial insurance hypothesis by demonstrating that landscape‐scale functional redundancy offsets the impact of local species losses and confers community‐level resistance to primary forest disturbance.Abstract in portuguese is available with online material.

Ecology and Conservation of the Laotian langur Trachypithecus laotum in a Protected Area of Laos (Southeast Asia)

Terrestrial species from the Lao People’s Democratic Republic (PDR) are under high threat due to deforestation and overhunting. Previous studies have even defined these forests as subjected to an “empty forest syndrome”, a condition in which forests that are apparently well preserved are instead almost deprived of vertebrate faunas due to extreme exploitation by local communities. Forest specialists, including several primates, are among the most threatened species in the country. The Laotian langur (Trachypithecus laotum) is endemic to Lao PDR, is listed as Endangered by the IUCN Red List, and it is one of the least studied species in the region. A survey on the local distribution, life history and conservation status of the Laotian langur was carried out in Phou Hin Poun National Protected Area, Khammouane Province of Lao PDR. The survey consisted of an initial phase with interviews to select key informants on the Laotian langur and the other primate species of the area. Then, a phase of field surveys along forest transects, totaling 64.1 km of 21 transects, yielded a record of 35 individuals in 9 groups. The highest encounter/detection rate of the Laotian langur was 1 group per km at one sector of the park. In contrast, it was much lower (0.18–0.34 groups/km) in the rest of the protected area. The group sizes were much lower than those observed in the same area between 1994 and 2010, thus suggesting a decline in the population size of langurs. This decline may be linked to habitat loss (timber extraction and mining). Still, also overhunting, as signs of poaching were observed during our field surveys. This was also supported by the reports of our interviewees. Laotian langurs were observed to be sympatric and interact while foraging with the Assamese macaque (Macaca assamensis). In the cases of sympatric occurrence between the two species, we observed that subtle mechanisms of niche partitioning may occur to reduce interspecific competition for food. Further research on the population and ecology of this endangered langur should be conducted to understand the species and aid its conservation.

Large-scale importance of microbial carbon use efficiency and necromass to soil organic carbon.

Optimal methods for incorporating soil microbial mechanisms of carbon (C) cycling into Earth system models (ESMs) are still under debate. Specifically, whether soil microbial physiology parameters and residual materials are important to soil organic C (SOC) content is still unclear. Here, we explored the effects of biotic and abiotic factors on SOC content based on a survey of soils from 16 locations along a ~4000km forest transect in eastern China, spanning a wide range of climate, soil conditions, and microbial communities. We found that SOC was highly correlated with soil microbial biomass C (MBC) and amino sugar (AS) concentration, an index of microbial necromass. Microbial C use efficiency (CUE) was significantly related to the variations in SOC along this national-scale transect. Furthermore, the effect of climatic and edaphic factors on SOC was mainly via their regulation on microbial physiological properties (CUE and MBC). We also found that regression models on explanation of SOC variations with microbial physiological parameters and AS performed better than the models without them. Our results provide the empirical linkages among climate, microbial characteristics, and SOC content at large scale and confirm the necessity of incorporating microbial biomass and necromass pools in ESMs under global change scenarios.

Enter the Matrix: Use of Secondary Matrix by Mouse Lemurs

Madagascar is home to many threatened and endemic primate species, yet this island has seen dramatic declines in lemur habitat due to forest loss. This forest loss has resulted in an increasingly fragmented forest landscape, with fragments isolated from each other by grasslands (i.e., matrix). The grassland matrix is not entirely homogeneous containing matrix elements such as isolated trees and shrubs and linear features such as drainage lines. Because most lemurs are predominantly arboreal, they may preferentially use matrix elements to facilitate dispersal between fragments for access to mates or reduce feeding competition, allowing gene flow between fragments of habitat. Therefore, it is important to understand to what degree they use the matrix. We investigated matrix use in two mouse lemurs, the grey mouse lemur (Microcebus murinus) and the golden-brown mouse lemur (Microcebus ravelobensis) in a fragmented landscape in northwest Madagascar. We tested the predictions that: (1) lemurs use matrix less often than forest fragments, (2) if they use the matrix, then they will preferentially use matrix elements compared to grassland, and (3) M. murinus will disperse into the matrix further than M. ravelobensis. In 2011, we visually surveyed line transects in four areas containing matrix elements and four adjacent forest fragments during nocturnal walks. In 2017, we set up traplines in four areas of the matrix containing matrix elements, three areas that were grassland, and six traplines in adjacent fragments. We compared the relative abundance of mouse lemurs in matrix transects to fragmented forest transects, and the relative abundance of captured lemurs in matrix elements, grassland, and fragment traplines. We found that encounter rates of mouse lemurs did not significantly differ between the matrix and fragmented forest transects or traplines. Our sample size was too low to determine if the mean distance from the forest was greater for either Microcebus spp. Our study highlights that mouse lemurs do use matrix elements and there may be interspecific differences in use. Further research is needed to confirm species-specific matrix use, why mouse lemurs use matrix, and how much matrix elements facilitate movement for each species in fragmented landscapes.

Options for estimating horizontal visibility in hemiboreal forests using sparse airborne laser scanning data and forest inventory data

Abstract Horizontal visibility v in hemiboreal forest transects was measured in the field and then predicted, both from forest inventory (FI) data and from airborne laser scanning (ALS) data. Stand density N and mean diameter at breast height D were used as arguments in an FI predictive model assuming Poisson distribution of trees on a horizontal plane. It was found that a lack of FI data on forest regrowth and understorey trees caused v to be overestimated. Point cloud metrics of sparse ALS data from summer 2017 and spring 2019 were used as predictive variables for v in regression models. The best models were based on three variables: the 10th percentile of the point cloud height distribution, relative density of returns in a horizontal layer ranging 0.7–2.2 m above the ground, and canopy cover. The models had a coefficient of determination of up to 67% and a residual standard error of less than 25 m. In forests in which fertile soil produces rapid height growth of understorey woody vegetation after recent thinning, visibility was found to be substantially overestimated because the understorey was not detected by the lidar measurements.

Phorophyte type determines epiphyte-phorophyte network structure in a Mexican oak forest

Phorophytes are assumed to act as facilitators for epiphytes, but empirical evidence indicates that they also act as amensalists. While few epiphytes can colonize most phorophytes, some epiphytes (such as orchids) appear in few phorophytes and/or have low population sizes, suggesting that are strongly phorophyte-limited. We assume that phorophyte type must determine the structure of the interaction network between epiphytes and phorophytes. In order to identify phorophyte type, we studied their distribution of epiphytes and, using two methods for measuring interaction intensity (raw and standardized data), analyzed the structure of the epiphyte-phorophyte interaction network. We quantified and identified all of the epiphytes and their phorophytes in all of the woody plants (diameter at breath height ≥ 5 cm) found in five 0.1 ha transects (10 × 100 m) in an oak forest of central Mexico. Acacia farnesiana and Bursera copallifera were the preferred phorophytes with greater epiphyte loads than would be expected by chance, while Quercus magnoliifolia and Q. candicans were limiting, with less epiphytes than would be expected by chance. In the network analyses, the preferred phorophytes concentrated interactions. These included B. copallifera, which, despite being infrequent, had the highest intensity of interaction with the most abundant epiphyte (Viridantha atroviridipetala: Bromeliaceae), while the most abundant phorophyte (Q. magnoliifolia) had low interaction intensity. This study reinforces the increasing evidence showing that epiphytes can be phorophyte-limited and shows that the type and importance of phorophytes within the interaction network is not determined by their abundance.

Species diversity and threats on the habitat of Vatica javanica in the Ciangir Forest, Indonesia

Vatica javanica is one of the endemic dipterocarp species in Java. It is highly prioritized to be conserved and categorized as critically endangered A1cd, D ver 2.3 based on International Union for Conservation of Nature red list. There is still a lack of ecological study related to this Javan endemic dipterocarp. At the national level, V. javanica is categorized as critical EN A2cd; B2ab (ii, iii) ver.4.0. Information on the current population condition is essential to support the baseline data for the conservation effort of the species. To investigate the species diversity and threats in V. javanica’s natural habitat, we established 26 transects of 20m x 50m based on the V. javanica’ occurrence and identified all the plant species (d = >1cm) composed V. javanica’s population. V. javanica was only found at four out of 26 transects in the Ciangir forest, Kuningan District, West Java, Indonesia. The result showed that the species diversity in this population was very high, Simpson diversity index (α) = 0.96. Furthermore, based on the result of the critical value index (IVI), the population was dominated by V. javanica (20.97), Ficus sp. (11.01), Eurya acuminata (11.01), Dillenia obovata (10.72), and Lithocarpus sundaicus (10.31). This study identified that natural (landslides) and human intervention (land conversion) as the major threats for the species.

Catchment-wide variations and biogeochemical time lags in soil fatty acid carbon isotope composition for different land uses: Implications for sediment source classification

Stable carbon isotope values of fatty acids (>20 C-atoms) (δ13C-FAs) have been increasingly used to apportion sediment sources using isotope mixing models. Understanding the variation of δ13C-FAs within catchment land uses is crucial for correct classification of sediment sources but it has rarely been evaluated. Here, we assessed the variability of δ13C values of FAs (C22–32) in soils under land uses within a catchment (23 km2) in the mid-hills of Nepal. High δ13C-FA variability in agricultural terraces (−32.8‰ to −20.2‰) and mixed forest (−37.3‰ to −22.3‰) was observed. This is due to differences in inputs of FAs of different chain-lengths with variable δ13C-FAs values by C3 and C4 crops as well as from farmyard manure in agricultural terraces. The pine plants succession in the forest and differences in FA preservation explained the observed variation in δ13C-FA values in a mixed forest. A pine forest transect that had undergone land cover change about 40 years ago showed high variability of δ13C-FA values strongly linked to legacy effects of previous C4 crops. Importantly, soils from the border of a land use and fresh surface deposits mostly increased the within-land use variability of δ13C-FAs values. Overall, δ13C-FA values have low potential to function as a robust tracer for high resolution discrimination of land uses and the validity of a priori sediment source classification is most questionable in catchments that have undergone land cover change. Cluster analysis was promising for identifying and combining functionally similar land uses to define more meaningful sediment sources at the catchment scale.

Estructura del bosque altoandino y páramo en el Macizo de Bijagual, Boyacá, Colombia

Abstract. Structure of the high Andean forest and paramo in the Bijagual Massif, Boyacá, Colombia. Introduction: Colombia has increased research due to the necessity of knowing the country´s biodiversity and ecosystems, as well as to establish priorities for their protection throughout the national territory. The knowledge of the Boyacá ecosystems and the high Andes are not an exception. Objective: this work provides information on diversity and structure of the Bijagual Massif, a high mountain area defined as a biological corridor, with paramo (2 900 - 3 460 masl) and high Andean forest (2 682 -3 268 masl) ecosystems. Methods: Sampling consisted of 27 random transects in the high Andean forest (100 x 2.5 m) and 13 in the paramo (10 x 5 m). We recorded abundance data, growth form, height, coverage, DAP and basal area. We calculated diversity analyses (H’, D and Jaccard), of vertical and horizontal structure. Results: Estimated species richness of 429 species in 86 families. Similarity does not exceed 46 % between sampling units, data that supports the heterogeneity of the Bijagual Massif. We recorded 10 777 individuals in the forest. The most abundant and richest growth forms were herbs (2 595/104) and trees (2 189/67), while lower in abundance and richness were vines (466/29). In the paramo 3 337 individuals, with a dominance of herbs (in frailejonal, shrubs and pajonal), rosettes (in frailejonal and pajonal) and shrubs. Species with ecological representativeness are: Clusia multiflora, C. elliptica, C. alata, Weinmannia rollottii, Brunellia comocladifolia and Viburnum triphyllum. Conclusion: These results confirm the uniqueness of these high mountain ecosystems and the need to maintain the heterogeneity before the occurence of soil transformation processes. The last, is supported by the high species turnover among sampling units, the dominance per physiognomic type, and the ecological significance of arboreal and shrub species in the forest and those that reoccur in the paramo. Here we define Bijagual, as a biological corridor with great biodiversity.

How forest structure varies with elevation in old growth and secondary forest in Costa Rica

Clarifying how forests vary with elevation can inform our understanding of forests and their responses to climate. Despite the prevalence of secondary forests (defined as regrowth after disturbance), few studies have examined how their structure and recovery vary with elevation. Here, in apparently the first study of its kind, we explored how basal area, stem density and community wood specific gravity of stems ≥ 10 cm diameter vary along an old growth and a 25–30 years old secondary forest transect, each spanning over 2000 m of elevation in Costa Rica. The old growth transect comprises 29 plots of 0.25 ha from 440 to 2900 m.asl. and the secondary 28 plots of 0.1 ha and 10 plots of 0.25 ha from 600 to 2750 m.asl. We characterized how stand characteristics vary with elevation using linear and generaled additive models. To our surprise basal area increased with elevation not only in the old growth (from 24 to 56 m2/ha) but also in the secondary forest (11 to 59 m2/ha). This increase reflected the greater density of larger trees (≥40 cm diameter) at higher elevations. Basal area decreased with inferred water availability (global aridity index) in the secondary, but not the old growth forest. Surprisingly, wood specific gravity revealed no clear pattern with elevation in either transect though within stand variation decreased with elevation in both. In both forests, basal area is positively correlated with mean wood specific gravity, being significantly greater in stands with less variation in wood specific gravity. We interpret these patterns as resulting from reduced mortality of larger trees at higher versus lower elevations in both old-growth and secondary forest. Our results imply that planting trees to enhance recovery would be more beneficial in lowland than in high elevation forests.

Does metal pollution affect the stoichiometry of soil-litter food webs?

To date, the field of ecological stoichiometry has focused mainly on macro-elements in aquatic systems. We investigated terrestrial systems and included micro-elements in the study to assess the elemental transfer in a detritivorous food web. We compared the food webs of six sites differing in the type and degree of metal pollution along two forest transects contaminated with copper or zinc. We measured 11 elements in the litter, herbivores, detritivores, predators and omnivores. Based on the concentrations of the elements, the differences between the trophic groups were visualized using PCA. At all the sites, the litter C:N, C:P, C:K and C:Na ratios were higher than those in the animals. The C:Cu, C:Zn and C:Ca ratios of the invertebrate trophic groups were significantly different from each other. The calculated resource:consumer N:P ratio suggests that invertebrates in the studied forests are N limited but not P limited. The presence of similar patterns at all the sites suggests that metal pollution at the studied intensity somewhat affects the transfer of elements in terrestrial macro-invertebrate food webs.

Artificial light at night, in interaction with spring temperature, modulates timing of reproduction in a passerine bird.

The ecological impact of artificial light at night (ALAN) on phenological events such as reproductive timing is increasingly recognized. In birds, previous experiments under controlled conditions showed that ALAN strongly advances gonadal growth, but effects on egg‐laying date are less clear. In particular, effects of ALAN on timing of egg laying are found to be year‐dependent, suggesting an interaction with climatic conditions such as spring temperature, which is known have strong effects on the phenology of avian breeding. Thus, we hypothesized that ALAN and temperature interact to regulate timing of reproduction in wild birds. Field studies have suggested that sources of ALAN rich in short wavelengths can lead to stronger advances in egg‐laying date. We therefore tested this hypothesis in the Great Tit (Parus major), using a replicated experimental set‐up where eight previously unlit forest transects were illuminated with either white, green, or red LED light, or left dark as controls. We measured timing of egg laying for 619 breeding events spread over six consecutive years and obtained temperature data for all sites and years. We detected overall significantly earlier egg‐laying dates in the white and green light vs. the dark treatment, and similar trends for red light. However, there was a strong interannual variability in mean egg‐laying dates in all treatments, which was explained by spring temperature. We did not detect any fitness consequence of the changed timing of egg laying due to ALAN, which suggests that advancing reproduction in response to ALAN might be adaptive.

Phenotypic matching in ovipositor size in the parasitoid Galeopsomyia sp. (Hymenoptera, Eulophidae) attacking different gall inducers

ABSTRACT Parasitoid ovipositor size importantly affects host choice; those attacking exposed hosts usually have shorter ovipositors compared to those needing drilling deeper through substrates such as plant tissue and gall tissue. Most studies treat this theme at the interspecific level, and the aim of this work was to test for intraspecific variation and phenotypic matching in ovipositor size for Galeopsomyia sp. attacking galls. Galls were sampled from Guapira opposita(Nyctaginaceae), a host plant to five species of Bruggmannia gallers (Diptera, Cecidomyiidae) in southern Brazil: Bruggmannia elongata, B. robusta, B. acaudata, and two undescribed species of Bruggmannia (sp. 1 and sp. 2). On forest transects, all galls from the 30 first galled plants found were sampled and kept in sealed plastic bags until parasitoid emergence. A total of 15 samples were done along two years. We measured galler last instar larvae length and gall thickness for each galling species, and ovipositor length for all Galeopsomyia sp. individuals emerging from the galls. There were no differences in larval length among galler species. However, Bruggmannia sp. 1 and sp. 2 galls were significantly thicker than those of B. acaudata, and the latter thicker than both B. elongata and B. robusta galls. Wasp ovipositor size differed significantly between those coming from Bruggmannia sp. 1 and sp. 2 galls relative to all others. Host extended phenotype size is thus fundamental to determine parasitoid size, but in this case host (larval) size does not change among species, although gall thickness was different. Thicker galls were attacked by larger parasitoids with longer ovipositors, denoting phenotypic matching. Thicker galls appear to be selecting larger parasitoid individuals, which in the long run can lead to important evolutionary change as well.

Dissolved Organic Carbon Flux On Forest Toposequences in Jambi, Indonesia

DOC fluxes were studied within soil profiles on forest toposequences transect of Bukit Dua Belas National Park and Harapan Forest, Jambi, Indonesia. DOC concentration was determined using NPOC (Non Purgeable Organic Carbon) method. Amount and DOC flux from soil horizons on the lower slope was significantly higher than that from the middle and the upper slopes. Amount and DOC flux from AO soil horizon was significantly higher than that from AB and B soil horizons. DOC was maximally accumulated from AO soil horizon of soil profile on lower slope during rainy season.