Natural Forest Gaps Research Articles

Coping with extremes: Responses of Quercus robur L. and Fagus sylvatica L. to soil drought and elevated vapour pressure deficit

Climate change, particularly droughts and heat waves, significantly impacts global photosynthesis and forest ecosystem sustainability. To understand how trees respond to and recover from hydrological stress, we investigated the combined effects of soil moisture and atmospheric vapour pressure deficit (VPD) on seedlings of the two major European broadleaved tree species Fagus sylvatica (FS) and Quercus robur (QR). The experiment was conducted under natural forest gap conditions, while soil water availability was strictly manipulated. We monitored gas exchange (net photosynthesis, stomatal conductance and transpiration rates), nonstructural carbohydrates (NSC) concentration in roots and stomatal morphometry (size and density) during a drought period and recovery. Our comparative empirical study allowed us to distinguish and quantify the effects of soil drought and VPD on stomatal behavior, going beyond theoretical models. We found that QR conserved water more conservatively than FS by reducing transpiration and regulating stomatal conductance under drought. FS maintained higher stomatal conductance and transpiration at elevated VPD until soil moisture became critically low. QR showed higher intrinsic water use efficiency than FS. Stomata density and size also likely played a role in photosynthetic rate and speed of recovery, especially since QR with its seasonal adjustments in stomatal traits (smaller, more numerous stomata in summer leaves) responded and recovered faster compared to FS. Our focal species showed different responses in NSC content under drought stress and recovery, suggesting possible different evolutionary pathways in coping with stress. QR mobilized soluble sugars, while FS relied on starch mobilization to resist drought. Although our focal species often co-occur in mixed forests, our study showed that they have evolved different physiological, morphological and biochemical strategies to cope with drought stress. This suggests that ongoing climate change may alter their competitive ability and adaptive potential in favor of one of the species studied.

The Importance of Natural Forest Gap on Migratory Birds in a Lower Montane Forest at Doi Suthep-Pui National Park

The Importance of Natural Forest Gap on Migratory Birds in a Lower Montane Forest at Doi Suthep-Pui National Park

Temporal variation in the population of bulbuls (Family Pycnonotidae) in lower montane forest, Northern Thailand

Abstract. Ponpituk Y, Siri S, Safoowong M, Suksavate W, Marod D, Duengkae P. 2020. Temporal variation in the population of bulbuls (Family Pycnonotidae) in lower montane forest, Northern Thailand. Biodiversitas 21: 3644-3649. Temporal variations in the population of bulbuls (Family Pycnonotidae) were studied over the course of four years in a 16-ha lower montane permanent plot, Northern Thailand. This study aimed to determine the relationship of the temporal variation of forest gaps with the population size of the bulbul, which plays a crucial role in seed dispersal and insect control in tropical forest ecosystems. This long-term monitoring study in a permanent plot was conducted monthly from January 2016 through October 2019. Data were collected using the mist-netting method for the capture-recapture protocol with individual bird banding. A total of 33,120 traps hour for 46 months,180 traps hour per day and 720 traps hour per month were recorded. The banding of a total of 94 individual bulbuls resulted in their classification into 5 species, consisting of Puff-throated Bulbul (Alophoixus pallidus), Mountain Bulbul (Ixos mcclellandii), Black-crested Bulbul (Pycnonotus flaviventris), Ashy Bulbul (Hemixos flavala) and Flavescent Bulbul (Iole virescens). The annual average density of bulbul for four years tended to decrease, but the difference was not significant. The highest average population occurred in 2016 and the lowest in 2018 with the changes being attributable to forest gap. Over time, monthly detection of bulbuls decreased gradually under closed canopy conditions, while in forest gaps, bird detection remained constant. As gap conditions so did detection probabilities. Our findings suggest that natural forest gaps can play an essential role as a temporal inhibitor to the rapid bird population decrease in the lower montane forest. This study will be useful for bird conservation and in balancing ecosystems for sustainability and providing interest in conservation initiatives requiring spatially explicit estimates of density.

Insects and light interact to mediate vine colonization of fast growing Microberlinia bisulcata tree seedlings in gaps of an African rain forest

AbstractVines thrive in lowland tropical forests, yet the biotic factors underlying their colonization of host tree seedlings and saplings remain surprisingly understudied. Insect herbivores presumably could influence this process, especially where disturbance has opened the canopy (i.e., gaps)—temporary areas of higher primary productivity favoring the recruitment of vines and trees and invertebrates in forests—but their impact on vine colonization has never been experimentally tested. Using data from an insect herbivore exclusion (mesh‐netting cages) experiment conducted in an African rain forest (Korup, Cameroon), I logistically modeled the probability of vines colonizing seedlings of three co‐dominant species (Microberlinia bisulcata vs. Tetraberlinia bifoliolata and T. korupensis) in paired shaded understory and sunny gap locations (41 blocks across 80 ha, starting n = 664 seedlings) in a 1–2‐yr period (2008–2009). Vine colonization occurred almost exclusively in gaps, occurring on 16% of seedlings there. Excluding herbivores in gaps doubled colonization of the light‐demanding and faster growing M. bisulcata but had negligible effects on the two shade‐tolerant, slower growing and less palatable Tetraberlinia species, which together were twice as susceptible to vines under natural forest gap conditions (controls). When protected from herbivores in gaps, more light to individual seedlings strongly increased vine colonization of M. bisulcata whereas its well‐lit control individuals supported significantly fewer vines. These results suggest vines preferably colonize taller seedlings, and because light‐demanding tree species grow faster in height with more light, they are more prone to being colonized in gaps; however, insect herbivores can mediate this process by stunting fast growing individuals so that colonization rates becomes more similar between co‐occurring slow and fast growing tree species. Further influencing this process might be associational resistance or susceptibility to herbivores linked to host species’ leaf traits conferring shade‐tolerant ability as seedlings or saplings. A richer understanding of how vines differentially influence forest regeneration and species composition may come from investigating vine–tree–herbivore interactions across light gradients, ideally via long‐term studies and intercontinental comparisons.Abstract in French is available with online material.

Effect of organic manure fertilizer on the growth of Macaranga gigantea

Abstract. Susanto D, Auliana, Kusuma R, Amirta R. 2019. Effect of organic manure fertilizer on the growth of Macaranga gigantea. Nusantara Bioscience 11: 166-171. M. gigantea planting research has been conducted in several habitats such as natural forest gaps, drained peatland and soil with highly degraded land for rehabilitation. This study investigated the effect of organic manure fertilization on soil, tissue chemical properties and growth performance of Macaranga gigantea planted at dense space of 2,5 m x 2,5 m. The experiment used a randomized block design with treatment of fertilization using goat manure with five gradual concentrations namely P0 (0 g), P1 (100 g), P2 (200 g), P3 (300 g) and P4 (400 g) in which each treatment consisted of three groups with 20 replications for each group, totaling 300 seedlings observed. The results showed that organic manure fertilization promoted stem height, stem diameter, leaf number and nutrient concentrations in the leaves of four-month-old M. gigantea. The best growth performance was gained from the treatment of P3 (300 g), followed by P2, P1, P4, and P0. The highest nutrient contained in leave tissue was potassium, followed by calcium, magnesium, nitrogen and available phosphorus.

The natural forest gaps maintenance diversity of understory birds in Mae Sa-Kog Ma Biosphere Reserve, northern Thailand

Siri S, Ponpituk Y, Safoowong M, Marod D, Duengkae P. 2019. The natural forest gaps maintenance diversity of understory birds in Mae Sa-Kog Ma Biosphere Reserve, northern Thailand. Biodiversitas 20: 181-189. We compared the species composition and feeding guilds between under closed canopies and forest gaps in the low-elevation montane evergreen forest in Mae Sa-Kog Ma Biosphere Reserve. Monthly mist netting was used to capture birds from January 2015 to December 2017. In total, 958 individual birds belonging to 65 species were captured over 25,920 sampling hours. Of the total number of birds, 475 were from 51 species (Shannon-Wiener index: H' 2.974) under closed canopies and 483 were from 47 species (H' 2.985) in forest gaps. The number of bird species in gaps increased rapidly and constantly through 1 year following gap creation. Forest gap localities contained 48% of the understory birds in the area. Foliage–gleaning insectivores were the dominant bird feeding guild in both areas. Some species such as Erythrura prasina is a nomadic bird were found on first year of the forest gap only. Overall, we found that the forest gaps created by natural disturbances in the Mae Sa-Kog Ma Biosphere Reserve had no negative impact on the diversity of understory bird communities. The natural forest gap are created by intermediate disturbance promotes a relatively high biodiversity of birds in the ecosystem.

Environmental control of natural gap size distribution in tropical forests

Abstract. Natural disturbances are the dominant form of forest regeneration and dynamics in unmanaged tropical forests. Monitoring the size distribution of treefall gaps is important to better understand and predict the carbon budget in response to land use and other global changes. In this study, we model the size frequency distribution of natural canopy gaps with a discrete power law distribution. We use a Bayesian framework to introduce and test, using Monte Carlo Markov chain and Kuo–Mallick algorithms, the effect of local physical environment on gap size distribution. We apply our methodological framework to an original light detecting and ranging dataset in which natural forest gaps were delineated over 30 000 ha of unmanaged forest. We highlight strong links between gap size distribution and environment, primarily hydrological conditions and topography, with large gaps being more frequent on floodplains and in wind-exposed areas. In the future, we plan to apply our methodological framework on a larger scale using satellite data. Additionally, although gap size distribution variation is clearly under environmental control, variation in gap size distribution in time should be tested against climate variability.

Woody flora of natural forest gaps in a bamboo-dominated forest remnant in southwestern Amazonia

Abstract: Forest gaps, created by the falling of one or more trees, have been seen as a key factor for the maintenance of local plant diversity in tropical forests. In this study, our goal was to determine the floristic composition of woody plants colonizing natural gaps and in the understory of an open, bamboo-dominated (Guadua weberbaueri Pilg.) forest in southwestern Amazonia, Acre, Brazil. We sampled and identified woody plants (≥1 m tall and DBH≤10 cm) in 20 forest gaps and nine adjacent understories. In total, 1656 plants were identified in 159 species, 116 genera and 45 families. A list of species was created, containing habitat, habit, functional group, threat status (Brazilian Flora Red List) and abundance data for each species.

Effects of Forest Gaps on Soil Properties in Castanopsis kawakamii Nature Forest.

The aim of this study is to analyze the effects of forest gaps on the variations of soil properties in Castanopsis kawakamii natural forest. Soil physical and chemical properties in various sizes and development stages were studied in C. kawakamii natural forest gaps. The results showed that forest gaps in various sizes and development stages could improve soil pore space structure and water characteristics, which may effectively promote the water absorbing capacity for plant root growth and play an important role in forest regeneration. Soil pore space structure and water characteristics in small gaps showed more obvious improvements, followed by the medium and large gaps. Soil pore space structure and water characteristics in the later development stage of forest gaps demonstrated more obvious improvements, followed by the early and medium development stages. The contents of hydrolysable N and available K in various sizes and development stages of forest gaps were higher than those of non-gaps, whereas the contents of total N, total P, available P, organic matter, and organic carbon were lower. The contents of total N, hydrolysable N, available K, organic matter, and organic carbon in medium gaps were higher than those of large and small gaps. The disturbance of forest gaps could improve the soils’ physical and chemical properties and increase the population species’ richness, which would provide an ecological basis for the species coexistence in C. kawakamii natural forest.

Forest Gaps Inhibit Foliar Litter Pb and Cd Release in Winter and Inhibit Pb and Cd Accumulation in Growing Season in an Alpine Forest.

AimsThe release of heavy metals (such as Pb and Cd) from foliar litter play an important role in element cycling in alpine forest ecosystems. Although natural forest gaps could play important roles in the release of heavy metals from foliar litter by affecting the snow cover during the winter and solar irradiation during the growing season, few studies have examined these potential roles. The objectives of this study were to document changes in Pb and Cd dynamics during litter decomposition in the center of gaps and under closed canopies and to investigate the factors that controlled these changes during the winter and growing seasons.MethodsSenesced foliar litter from six dominant species, including Kangding willow (Salix paraplesia), Masters larch (Larix mastersiana), Mingjiang fir (Abies faxoniana), Alpine azalea (Rhododendron lapponicum), Red birch (Betula albosinensis) and Mourning cypress (Sabina saltuaria), was placed in litterbags and incubated between the gap center and closed canopy conditions in an alpine forest in the eastern region of the Tibetan Plateau. The litterbags were sampled at the snow formation stage, snow coverage stage, snow melt stage and during the growing season. The Pb and Cd concentrations in the sampled foliar litter were determined by acid digestion (HNO3/HClO4).Important findingsOver one year of decomposition, Pb accumulation and Cd release from the foliar litter occurred, regardless of the foliar litter species. However, Pb and Cd were both released from the foliar litter during the winter and accumulated during the growing season. Compared with the gap center and the canopy gap edge, the extended gap edge and the closed canopy showed higher Pb and Cd release rates in winter and higher Pb and Cd accumulation rates during the growing season, respectively. Statistical analyses indicate that the dynamics of Pb were significantly influenced by frequent freeze–thaw cycles in winter and appropriate hydrothermal conditions during the growing season, the dynamics of Cd were strongly influenced by species and the presence of a forest gap at different decomposition stages. These results show that forest gaps could inhibit Pb and Cd release from foliar litter in the alpine forest of western Sichuan. In addition, a decrease in the snow depth in the winter warming scenario would promote the release of Pb during foliar litter decomposition. There exist some difference that may be influenced by litter quality, microenvironment and microtopography during litter decomposition.

Diversity and network structure of invertebrate communities associated to Heliconia species in natural and human disturbed tropical rain forests

We analyzed the influence of natural and anthropogenic habitat disturbance on the structure of invertebrate communities living on two species of Heliconia herbs. We compared the invertebrate community structure associated to both species growing in natural forest gaps, on road edges for H. latispatha, and in riparian vegetation for H. collinsiana. We assessed the topological structure of individual-based Heliconia–invertebrate networks. Species richness was greater in H. collinsiana inhabiting riparian vegetation but no differences were found in the diversity of invertebrates for any Heliconia species and habitat. Invertebrate abundance was greater in gaps for H. latispatha and in riparian vegetation for H. collinsiana showing a species turnover in human disturbed habitats. The invertebrate community was not randomly assembled but highly nested, revealing a structured pattern for all habitat conditions. Heliconia–invertebrate network properties appear to be maintained in human disturbed habitats, despite differences in species richness, abundance and composition and host number and quality. Our study contributes to the understanding of the structure of ecological interactions in contrasting habitats. Because they provide food and habitat for the associated fauna and several microhabitats for colonization, heliconias could be used as habitat elements for invertebrate conservation in human impacted landscapes.

Development, survival, and phenotypic plasticity in anthropogenic landscapes: trade-offs between offspring quantity and quality in the nettle-feeding peacock butterfly.

Habitats selected for development may have important fitness consequences. This is relevant within the framework of niche shifts in human-dominated landscapes. Currently, the peacock butterfly (Aglais io) occurs ubiquitously, covering many habitat types, whereas its distribution used to be much more restricted. Indeed, its host plant (stinging nettle Urtica dioica) was limited to natural forest gaps on relatively nitrogen-rich soil, but due to land use changes and eutrophication, host plants are now quasi-omnipresent in Western Europe. In order to assess the impact of specific anthropogenic habitat types on host plant quality and environmental conditions for phenotypic trait values, an experiment was conducted in woodlands, field margins, and urban gardens. Larval development was studied in field enclosures, and adult traits were analyzed to test predicted effects of warmer and more nitrogen-rich conditions in field margins compared to woodlands and urban gardens. Survival to the adult stage was highest in woodlands and lowest in field margins, and whilst development time did not differ amongst habitat types, butterflies that developed in field margins were larger and had higher lipid content and wing loadings than conspecifics from woodlands and urban gardens. Nettles in field margins provided warmer microclimates. However, and contrary to predictions, the nitrogen level within host plant leaves was highest in woodlands. Hence, anthropogenic landscapes may pose a conflict for choosing what is ultimately the best breeding habitat, as survival was highest in woodlands (followed by urban gardens), but adults with highest fitness predictions were produced in field margins (and secondarily urban gardens).

Reorientation in Tilted Stems of Papaya by Differential Growth

Premise of research. Papaya (Carica papaya L.) is a fast-growing plant that is able to reorient quickly from a tilted position due to a local growth in the basal stem region. This seems to be a necessary adaptation in the struggle for light in the plant’s natural habitat, natural forest gaps. Interestingly, the stem anatomy of papaya consists exclusively of parenchymatous wood exhibiting substantial turgor pressure. The only reinforcing tissue is found in the bark, consisting of a lattice-like mesh of lignified fibers filled with parenchyma. This peculiar mechanism of reorientation raised questions concerning the role of turgor pressure during growth and the mechanical interactions between fiber mesh and parenchyma as a consequence of the unusual anatomy.Methodology. A set of mechanical measurements of sections of secondary phloem and xylem were conducted, comparing Young’s modulus and turgor pressure of the upper and lower sides of reerecting stems. Additionally, tissues from both sides were microscopically analyzed.Pivotal results. We found that Young’s moduli differed significantly between tissues from both sides of reerecting stems due to morphological adaptations. Experimental data showed that turgor pressure remained constant during cell expansion throughout the erecting process. Thus, cell growth and turgor pressure sustaining water inflow are in a state of equilibrium. Microscopic analyses revealed pronounced radially directed cell growth in the upper side of the xylem in comparison to the lower side.Conclusions. The stem bends upward via a coupling effect due to local secondary growth of the xylem affecting the peculiar phloem fiber arrangement. The xylem extends by directed radial growth on the upper side of leaning stems and generates an outward-pointing force. The phloem fiber mesh expands in a tangential direction. As a result, the structure contracts in an axial direction and eventually causes a pulling force on the upper side.

Effects of forest gaps on some microclimate variables in Castanopsis kawakamii natural forest

The objective of this study was to understand the effects of forest gap and variations in different seasons, gap size, locations and diurnal variations on forest microclimate and soil water content. Spatial and temporal distribution features of air temperature (TA), soil temperature (TS), relative humidity (h) and soil water content (Ψ) were measured in Castanopsis kawakamii natural forest gaps created by a severe typhoon or fallen dead trees. The results showed that: (1) the variations of TA, h, and TS in four seasons were extremely significant. The variations of Ψ in four seasons were extremely significant except for those between spring and summer. (2) The diurnal variations of TA and TS were expressed with a single peak curve. The diurnal variations of h and Ψ presented a high-low-high trend. (3) The variations of TA, h, and TS were extremely significant among the large, medium and small gaps in C. kawakamii natural forest. Medium gaps had the highest TA and the lowest h while small gaps were just contrary to medium gaps. The variations of Ψ were extremely significant for large, medium and small gaps except those between the medium and large gaps. (4) The TA, h, TS and Ψ were decreased from the gap center, canopy gap, expanded gap to understory. These results will help further our understanding of the abiotic and consequent biotic responses to gaps in the mid-subtropical broadleaved forests, which also provide a theoretical basis for the scientific management and population restoration of C. kawakamii natural forest.

Jodï horticultural belief, knowledge and practice: incipient or integral cultivation?

This paper describes the Jodï horticultural system, including belief, knowledge and practice aspects. The horticultural practices of the Jodï were previously characterized as 'incipient cultivation' but such practices were poorly described and documented. The antiquity of cultivation among this group is suggested by the prominence and significance of horticultural products and techniques in myth and ritual. Our field observations uncovered a fairly sophisticated system of plant management in swiddens, house gardens, trail gardens and natural forest gaps. An inventory of 67 cultivated plant species was documented, of which 36 are utilized for food, 20 for magical or medicinal purposes, and 11 for technology. The Jodï prolong the productive phase of their gardens for five years or more through successive planting-harvesting-replanting operations. Jodï swiddens display an elaborate polycultivated appearance and they possess at least five principal crops: plantain/banana, maize, yams, sweet potato, and sweet manioc. Another distinctive feature is the extensive use of natural gaps in the forest canopy as cultivation zones. The results of this study suggest that while Jodï horticultural practice is well integrated with a nomadic, foraging-dependent lifestyle, nevertheless this system does not deserve to be labeled as 'incipient' and instead is more integral than was recognized previously.

Competition Zone of Castanopsis kawakamii Seedlings by Single Slope Change Point Analysis

The competition among the Castanopsis kawakamii seedlings were calculated with improved competition model for individual tree of Hegyi,which were optimized by the exponential smoothing model.The optimum competition ranges were confirmed by single slope change point analysis.The results showed that:(1) The average competition intensity of the C.kawakamii seedlings decreased with increasing of the competition distance.The competition intensity decreased quickly at early stage and then slow down in a certain extent,and there existed a turning point in the change range called the seedlings competition zone in the C.kawakamii natural forest gap and understory.(2) The minimum mean square errors of the third index smooth values of the C.kawakamii seedlings competition intensity in the forest gap and understory were 0.401 5 and 0.385 1 when smoothing coefficient α=0.8 and α=0.7 respectively.By applying the method of single slope change point,the optimal sampling competition zone of the C.kawakamii seedlings competition intensity were 1.70 and 1.90 meters distance from the objective trees in forest gap and understory.The results help us to determine the competition zone for the C.kawakamii seedlings’ competition pattern.

Insect Herbivory and Leaf Disease in Natural and Human Disturbed Habitats: Lessons from Early‐SuccessionalHeliconiaHerbs

ABSTRACTThe interaction of plants with insect herbivores and fungal pathogens can affect community dynamics, but there is little information on how this antagonistic interaction may be altered in human‐disturbed tropical systems. We examined whether the amount and quality of foliar damage on the pioneer herbsHeliconia latispathaandHeliconia collinsianaare distinct on road edges and secondary riparian vegetation compared with natural gaps in continuous forest (controls) in Mexico. We also investigated some physical and biological mechanisms that may jointly explain such differences. The overall insect damage inH. latispathawas similar between road edges and natural forest gaps (8.0% vs. 7.2% of leaf area). Damage by caterpillars, however, decreased from 4.2 percent in forest gaps to 0.5 percent on road edges, whereas damage by leaf‐cutting ants increased from 0 to 5.8 percent. In secondary riparian vegetation, where none of the leaves sampled were attacked by ants, overall herbivore damage inH. collinsianawas less than half that observed in forest gaps (3.0% vs. 6.7%), and driven mainly by differences in caterpillar damage (2.5% vs. 6.2%). By contrast, attack by leaf fungal pathogens was two to three times greater in both human‐disturbed habitats than in gaps (8.2–9.6% vs. 3.7–4.2%). Potential mechanisms underlying these differences involved human‐induced shifts in air and soil temperature driven by greater light availability, as well as changes in relative humidity, leaf toughness, foliar condensed tannins, and local abundance of herbivores. Our results indicate that human disturbance alters insect herbivory and may increase proliferation of leaf disease.Abstract in Spanish is available in the online version of this article.

Influences of life history, environmental gradients, and disturbance on riparian tree regeneration in Western Oregon

In two related field studies: (1) a multiscale riparian forest inventory and (2) a comparative study of natural forest gap and nongap environments, we explored regeneration patterns of native riparian trees in relation to large- and small-scale ecological drivers in four western Oregon watersheds spanning a climatic gradient from dry to wet. Twenty-three tree species were classified by life history traits into five functional groups that differed in shade and drought tolerance; distribution and abundance of tree regeneration were analyzed by group. For most groups, seedling abundance varied substantially across the large scale climate gradient. In particular, drought tolerant species decreased sharply in abundance from the drier to wetter watersheds. Overall seedling frequency and diversity also decreased from the driest to wettest watersheds, while nurse log use increased. Regeneration of most, but not all, species was greater in gaps. Principal conclusions are that life history information was useful for categorizing species and quite predictive of regeneration behavior overall, yet for many species contextual factors such as climate, forest structure, and adjoining species were also very important. Species appeared to regenerate opportunistically wherever local conditions fell within their environmental tolerances and competitive abilities. Management or restoration of riparian forests, therefore, requires knowledge of site conditions, the life history of the riparian trees present, and in particular an understanding of the species’ environmental tolerances, disturbance responses, and competitive abilities relative to one another.

A structured inventory of spiders (Arachnida, Araneae) in natural and artificial forest gaps at Porto Urucu, Western Brazilian Amazonia

A preliminary survey of the spider fauna in natural and artificial forest gap formations at “Porto Urucu”, a petroleum/natural gas production facility in the Urucu river basin, Coari, Amazonas, Brazil is presented. Sampling was conducted both occasionally and using a protocol composed of a suite of techniques: beating trays (32 samples), nocturnal manual samplings (48), sweeping nets (16), Winkler extractors (24), and pitfall traps (120). A total of 4201 spiders, belonging to 43 families and 393 morphospecies, were collected during the dry season, in July, 2003. Excluding the occasional samples, the observed richness was 357 species. In a performance test of seven species richness estimators, the Incidence Based Coverage Estimator (ICE) was the best fit estimator, with 639 estimated species. To evaluate differences in species richness associated with natural and artificial gaps, samples from between the center of the gaps up to 300 meters inside the adjacent forest matrix were compared through the inspection of the confidence intervals of individual-based rarefaction curves for each treatment. The observed species richness was significantly higher in natural gaps combined with adjacent forest than in the artificial gaps combined with adjacent forest. Moreover, a community similarity analysis between the fauna collected under both treatments demonstrated that there were considerable differences in species composition. The significantly higher abundance of Lycosidae in artificial gap forest is explained by the presence of herbaceous vegetation in the gaps themselves. Ctenidae was significantly more abundant in the natural gap forest, probable due to the increase of shelter availability provided by the fallen trees in the gaps themselves. Both families are identified as potential indicators of environmental change related to the establishment or recovery of artificial gaps in the study area.

Use of Forest Edges by Bats in a Managed Pine Forest Landscape

ABSTRACT Forest edges often have increased species richness and abundance (edge effect) and affect spatial behaviors of species and dynamics of species interactions. Landscapes of intensively managed pine (Pinus spp.) stands are characterized by a mosaic of patches and linear forest edges. Managed pine forests are a primary landscape feature of the southeastern United States, but the effects of intensive management on bat communities are poorly understood. Insectivorous bats are important top predators in nocturnal forest food webs. We examined bat foraging behavior along forest edges and in 4 structurally distinct stand types (open‐canopy pine, prethinned pine, thinned pine, and unmanaged forest) within a managed pine forest in the coastal plain of North Carolina, USA. During May‐August, 2006 and 2007, we recorded echolocation calls using Pettersson D240X bat detectors linked to digital recorders at 156 sites. We also sampled nocturnal flying insects at each site using Malaise insect traps. We used negative binomial count regression models to describe bat foraging behavior relative to forest edges, stand types, and prey availability. Although some species showed affinities for certain stand types and prey items, bat activity patterns were most strongly related to forest edges. Edges were used extensively by 6 aerial‐hunting bat species, but avoided by Myotis species. Forest edges function similarly to natural forest gaps, by providing foraging opportunities for aerial‐hunting bat species. Therefore, the maintenance of forest edges in managed pine landscapes may enhance foraging habitat for aerial‐hunting bat species.