Regeneration patterns and persistence of the fog-dependent Fray Jorge forest in semiarid Chile during the past two centuries

The persistence of rainforest patches at Fray Jorge National Park (FJNP) in semiarid Chile (30°40′S), a region receiving approximately 147 mm of annual rainfall, has been a source of concern among forest managers. These forests are likely dependent on water inputs from oceanic fog and their persistence seems uncertain in the face of climate change. Here, we assessed tree radial growth and establishment during the last two centuries and their relation to trends in climate and canopy disturbance. Such evaluation is critical to understanding the dynamics of these semiarid ecosystems in response to climate change. We analyzed forest structure of six forest patches (0.2–22 ha) in FJNP based on sampling within 0.1 ha permanent plots. For the main canopy species, the endemic Aextoxicon punctatum (Aextoxicaceae), we used tree‐ring analysis to assess establishment periods, tree ages, growing trends and their relation to El Niño Southern Oscillation (ENSO), rainfall, and disturbance. The population dynamics of A. punctatum can be described by a continuous regeneration mode. Regeneration of A. punctatum was sensitive to different canopy structures. Growth release patterns suggest the absence of large scale human impact. Radial growth and establishment of A. punctatum were weakly correlated with rainfall and ENSO. If water limits forests patch persistence, patches are likely dependent on the combination of fog and rain water inputs. Forest patches have regenerated continuously for at least 250 years, despite large fluctuations in rainfall driven by ENSO and a regional decline in rainfall during the last century. Because of the positive influence on fog interception, forest structure should be preserved under any future climate scenario. Future research in FJNP should prioritize quantifying the long‐term trends of fog water deposition on forests patches. Fog modeling is crucial for understanding the interplay among physical drivers of water inputs under climate change.     

Structure and composition of edges next to regenerating clear‐cuts in mixed‐wood boreal forest

Abstract. We investigated the spatial and temporal pattern of edge influence on primary (forest structure) and secondary (understory structure and composition) responses at forest edges next to regenerating clear‐cuts in Populus‐dominated boreal forest in Alberta, Canada. We used before/after‐harvest comparisons to determine whether there were significant effects of edge creation in the first and second year after harvest. We also investigated 5‐ and 16‐yr‐old edges to determine whether their structure and composition were significantly different from interior forest. Distance of edge influence (20–60 m) was not extensive compared to findings from studies conducted in other forest types. In the first two years after harvest, there were significant primary responses to edge creation including increased tree mortality, snag breakage and amount of downed coarse woody debris; as well as secondary responses including prolific vegetative regeneration of Populus spp. and a decrease in total shrub cover. Significant edge effects were still detectable 5 and 16 yr after edge creation, despite the rapid regeneration of Populus‐ dominated forest in the adjacent clear‐cuts. These older edges showed evidence of past primary and secondary responses, including a more heterogeneous canopy, along with additional changes in under‐ story composition. At both younger and older edges the distance of edge influence was greater for secondary responses (up to 60 m) than for primary responses (10–20 m). We hypothesize that secondary responses to edge creation start later than primary responses and that the distance of edge influence is greater for secondary (vs. primary) responses.     

Edge influence on plant litter biomass in forest and savanna in the Brazilian cerrado

Edge influence, characterized by differences in ecosystem characteristics between the edge and the interior of remnants in fragmented landscapes, affects a variety of organisms and ecosystem processes. An important feature that may be affected by edges is the amount of plant litter, which provides important habitat for a large variety of organisms and influences ecological processes such as fire dynamics. We studied edge influence on plant litter and fine woody debris in the cerrado of São Paulo state, south‐eastern Brazil. We collected, sorted, dried and weighed plant litter along 180 m‐long transects perpendicular to three savanna and eleven forest edges adjacent to different anthropogenic land uses, with four to five transect per edge. There tended to be less biomass of the finer portions of fine woody debris at both savanna and forest edges. Graminoid litter at savanna edges was greater than in the corresponding interior areas, whereas other litter portions were either unaffected by edges or did not show consistent patterns in either savanna or forest. Edge influence was usually restricted to the first 20 m from the edge, was not influenced by edge characteristics and exhibited no clear differences between savanna and forest areas. Several mechanisms may have led to the variable patterns observed including variation in the plant community, plant architecture, and invasive species. The edge‐related variation in plant litter may putatively lead to, for example, increased fire frequency and intensity at the savanna edges and altered trophic dynamics at forest edges; the mechanisms and consequences of this edge influence should be addressed in future studies.     

Do edge effects increase the susceptibility of rainforest fragments to structural damage resulting from a severe tropical cyclone?

Abstract If changes in the structural characteristics of rainforest at edges are caused by wind, then physical damage from a tropical cyclone might be greatest at edges or in small fragments that have a high proportion of edge. We tested whether this was true of a fragmented rainforest landscape impacted by a category 4 severe tropical cyclone in March 2006. Six structural variables (canopy cover, canopy height, cover of ground vegetation, leaf litter, stem density and counts of woody debris) were surveyed at 18 rainforest sites (six small linear remnants, and both edges and interiors of six large remnants) on the Atherton Tableland in north‐eastern Queensland, Australia. Data collected 7 and 12 months after the passage of Cyclone Larry were compared with an identical survey conducted 4 years prior to the cyclone. The cyclone had large effects across many components of forest structure. However, sites within 30 m of forest edges in small and large remnants were not impacted more than the interiors of large remnants. It is likely that the high wind intensity from severe tropical cyclones overrides the modest wind protection provided by surrounding forest. The cyclone's effects were highly patchy at local scales (0.5–1.0 km), leading to an increase in among‐site variation in forest structure and the disappearance of significant spatial autocorrelation among large remnant edge‐interior site pairs which had existed prior to the cyclone. The main effect of Cyclone Larry at these study sites was to increase the spatial heterogeneity of forest structure at local scales.     

Viability of ecological processes in small Afromontane forest patches in South Africa

Abstract The conservation of biodiversity is dependent on protecting ecosystem‐level processes. We investigated the effects of fragment size and habitat edge on the relative functioning of three ecological processes – decomposition, predation and regeneration of trees – in small Afromontane forests in KwaZulu‐Natal, South Africa. Ten sampling stations were placed in each of four forest categories: the interior of three large indigenous forest fragments (100 m from the edge), the edges of these large fragments, 10 small indigenous fragments (<1 ha) and 10 small exotic woodlands (<0.5 ha). Fragment size and edge effects did not affect the abundance of the amphipod Talitriator africana, a litter decomposer, and overall dung beetle abundance and species richness significantly. Bird egg predation was marginally greater at large patch edges compared with the other forest categories, while seed predation did not differ among forest categories. Tree seedling assemblage composition did not differ significantly among large patch interiors and edges, and small indigenous fragments. Sapling and canopy assemblage composition each differed significantly among these three indigenous forest categories. Thus, while tree recruitment was not negatively affected by patch size or distance from the edge, conditions in small fragments and at edges appear to affect the composition of advanced tree regeneration. These ecological processes in Afromontane forests appear to be resilient to fragmentation effects. We speculate that this is because the organisms in these forests have evolved under fragmented conditions. Repeated extreme changes in climate and vegetation over the Pleistocene have acted as significant distribution and ecological extinction filters on these southern hemisphere forest biota, resulting in fauna and flora that are potentially resilient to contemporary fragmentation effects. We argue that because small patches and habitat edges appear to be ecologically viable they should be included in future conservation decisions.     

The Seedling Community of Tropical Rain Forest Edges and Its Interaction with Herbivores and Pathogens1

Edge effects alter biotic interactions and forest regeneration. We investigated whether edge creation affected the seedling community and its interactions with herbivores and leaf‐fungal pathogens. In forest edges and interior sites in Chiapas, Mexico, we counted all woody seedlings and species (10–100 cm tall) present in 1‐m² plots, measured their size (height and leaf number), and examined them for the occurrence of herbivory and pathogen damage. We investigated relationships between levels of damage and size, species richness and density. Species composition and biotic damage varied greatly among sites and habitats (edge vs interior). Late‐successional species dominated the community, but richness was lower in interior sites and species similarity was greater among edges than among interiors. Nearly all species (95%) present at edges and interiors showed herbivory damage, whereas 76 percent of the species in edge plots and 68 percent in interior plots showed pathogen damage. Although leaf area damaged by herbivores was similar between habitats (average 9.2%), pathogen damage was three times greater in edge plots (1.85%) than in interior plots (0.57%). Size was positively related to biotic damage at both habitats. Relationships between herbivory and pathogen damage and between pathogen damage and leaf number were significant only for edges. Biotic damage was not related to density or species richness. Overall, plant community structure was similar between habitats, but biotic damage was enhanced at edges. Thus, disease spread at edges may arise as a threat to tropical rain forest vegetation.     

西双版纳片断化望天树林气候边缘效应比较研究

对西双版纳片断望天林树（Shorea chinensis)林林缘小气候的季节、水平变化进行了观测研究,对比分析了4个个不小雨林斑块（30hm^2,25hm^2,20hm^2,3hm^2)的小气候边缘效应。结果表明：各雨林斑块林缘均存在明显的小气候边缘效应,其中在干季晴天最为明显,且在上较小斑块林缘出现最高气温及气日较差高于林外的现象;干季,部分林缘小气候要素（最高气温、总辐射、净辐射、最小相对湿度）林缘与林内的差值均是高于或大于雨季的相应值,而地表最高温林缘与林内的差值则是雨季强于干季,各斑块相比,小气候边缘效应波及林内的深度在最大斑块达至最浅（25m),而在最小斑块达到最深（35m)呈现出小气候边缘效应及其影响深度随片继雨林斑块面积减小而增强及向林内进一步延伸的趋势。     

Woody Debris in the Mangrove Forests of South Florida1

Woody debris is abundant in hurricane‐impacted forests. With a major hurricane affecting South Florida mangroves approximately every 20 yr, carbon storage and nutrient retention may be influenced greatly by woody debris dynamics. In addition, woody debris can influence seedling regeneration in mangrove swamps by trapping propagules and enhancing seedling growth potential. Here, we report on line‐intercept woody debris surveys conducted in mangrove wetlands of South Florida 9–10 yr after the passage of Hurricane Andrew. The total volume of woody debris for all sites combined was estimated at 67 m³/ha and varied from 13 to 181 m³/ha depending upon differences in forest height, proximity to the storm, and maximum estimated wind velocities. Large volumes of woody debris were found in the eyewall region of the hurricane, with a volume of 132 m³/ha and a projected woody debris biomass of approximately 36 t/ha. Approximately half of the woody debris biomass averaged across all sites was associated as small twigs and branches (fine woody debris), since coarse woody debris >7.5 cm felled during Hurricane Andrew was fairly well decomposed. Much of the small debris is likely to be associated with post‐hurricane forest dynamics. Hurricanes are responsible for large amounts of damage to mangrove ecosystems, and components of associated downed wood may provide a relative index of disturbance for mangrove forests. Here, we suggest that a fine:coarse woody debris ratio ≤0.5 is suggestive of a recent disturbance in mangrove wetlands, although additional research is needed to corroborate such findings.     

Effects of logging and coarse woody debris harvest on lepidopteran communities in the eastern deciduous forest of North America

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Down by the riverside: Riparian edge effects on three monkey species in a fragmented Costa Rican forest

Rivers represent natural edges in forests, serving as transition zones between landscapes. Natural edge effects are important to study to understand how intrinsic habitat variations affect wildlife as well as the impact of human-induced forest fragmentation. We examined the influence of riparian and anthropogenic edge on mantled howler, white-faced capuchin, Central American spider monkeys, and vegetation structure at La Suerte Biological Research Station (abbreviated as LSBRS), Costa Rica. We predicted lower monkey encounter rate, tree species richness, and median dbh at both edge types compared to interior and that monkeys would show species-specific responses to edge based on size and diet. We expected large, folivorous–frugivorous howler monkeys and small, generalist capuchins would be found at increased density in forest edge, while large, frugivorous spider monkeys would be found at decreased density in forest edge. We conducted population and vegetation surveys along interior, riparian, and anthropogenic edge transects at LSBRS and used GLMM to compare vegetation and monkey encounter rate. Tree species richness and median dbh were higher in forest interior than anthropogenic edge zones. Although spider monkey encounter rate did not vary between forest edges and interior, howler monkeys were encountered at highest density in riparian edge, while capuchins were encountered at highest density in anthropogenic edge. Our results indicate that diverse forest edges have varying effects on biota. Vegetation was negatively affected by forest edges, while monkey species showed species-specific edge preferences. Our findings suggest that riparian zones should be prioritized for conservation in Neotropical forests.     

Anthropogenic edges impact howler monkey (Alouatta palliata) feeding behaviour in a Costa Rican rainforest

Anthropogenic forest fragmentation impacts many aspects of animal behaviour, including feeding ecology. With forests increasingly fragmented in tropical regions due to human development, the proportion of forest edge (≤?100 m from clear-cut regions) is higher relative to forest interior. Forest edges differ in vegetation from interior, making it important to better understand how anthropogenic edges impact the feeding behaviour of primates such as mantled howler monkeys (Alouatta palliata). We predicted that howler monkeys would feed on higher-quality plant resources, from a larger number of tree families, and from larger trees in forest interior compared to anthropogenic forest edge. We surveyed howler monkey feeding behaviour across forest zones in a fragmented rainforest in Costa Rica, La Suerte Biological Research Station. We observed individual monkeys for 30-minute periods, collecting data on their feeding behaviour and tree use at 2-minute intervals. We measured feeding trees and recorded the plant parts and taxonomy of resources consumed. Monkeys consumed more leaves and fewer stems and fed from a smaller number of tree families in the forest interior, while they consumed fewer leaves and more stems and fed from a larger number of tree families in the forest edge. Monkeys also fed from larger, taller trees in the forest interior than the edge. The differences in howler monkey feeding behaviour between forest zones attest to the impact of human disturbance on howler monkey feeding ecology.

     

Effects of habitat fragmentation on the movement patterns and dispersal ability of the brown spiny rat (<Emphasis Type="Italic">Maxomys rajah</Emphasis>) in the Planted Forest Zone of Sarawak,Eastern Malaysia

Brown spiny rats (Maxomys rajah) were translocated from continuous secondary forest to small isolated patches of remnant native forest embedded within Acacia mangium plantation in the Planted Forest Zone of Sarawak, East Malaysia, and fitted with tracking spools to monitor behaviours in novel environments and to record responses to a range of habitat edge features. Forest roads, large clearings and acacia plantation compartments were found to pose barriers to dispersal of brown spiny rats over short temporal scales, whereas old regenerating haul trails were readily crossed on 50% of the encounters. Downed woody debris accounted for a greater proportion of the travel route compared with brown spiny rats tracked in secondary and primary forest in Sabah, which may represent heightened predator avoidance in new environments. Provision of downed woody debris within plantation compartments may improve the dispersal ability of brown spiny rats in this modified landscape, and thus promote metapopulation dynamics and colonisation of vacant habitat patches.     

Fog Water and Ecosystem Function: Heterogeneity in a California Redwood Forest

Fog is thought to influence ecological function in coastal forests worldwide, yet few data are available that illuminate the mechanisms underlying this influence. In a California redwood forest we measured water and nitrogen (N) fluxes from horizontally moving fog and vertically delivered rain as well as redwood tree function. The spatial heterogeneity of water and N fluxes, water availability, tree water use, and canopy N processing varied greatly across seasons. Water and N fluxes to soil (annual average of 98% and 89%, respectively) across the whole forest occurred primarily in the rain season and was relatively even across the whole forest. In contrast, below-canopy flux of fog water and N declined exponentially from the windward edge to the forest interior. Following large fog events, soil moisture was greater at the windward edge than anywhere else in the forest. Physiological activity in redwoods reflected these differences in inputs across seasons: tree physiological responses did not vary spatially in the rain season, but in the fog season, water use was greater, yet water stress was less, in trees at the windward edge of the forest versus the interior. In both seasons, vertical passage through the forest changed the amount of water and form and concentration of N, revealing the role of the tree canopy in processing atmospheric inputs. Although total fog water inputs were comparatively small, they may have important ecosystem functions, including relief of canopy water stress and, where there is fog drip, functional coupling of above- and belowground processes. Author Contributions  We make no distinction in effort and contribution between the first and second authors or between the third and fourth authors. HAE and KCW were responsible for project design, oversight, data analysis, synthesis, and writing. PHT analyzed N samples and contributed significantly to interpretation of data. TED established the initial tree physiology study site, provided and analyzed the data on tree physiology, and contributed to the synthesis of these data. MKF first identified the lack of connection between inputs and microbial processing and catalyzed synthesis regarding belowground processing. AME created figures, performed field and laboratory work, and was database manager. VKSB collected field samples and carried out the litterfall study. All authors edited the paper.     

Rain Forest Structure at Forest-Pasture Edges in Northeastern Costa Rica

Land-use change in the Sarapiquí region of Costa Rica has resulted in a fragmented forest landscape with abrupt edges between forest and pasture. Forest responses to edge effects vary widely and can significantly affect ecosystem integrity. Our objective was to examine forest structure at 20+ yr old forest-pasture edges in Sarapiquí. Three transects with 0.095-ha plots at seven distances from forest edges were established in each of six forest patches. Stem density, basal area, and aboveground biomass in trees and palms ≥ 10-cm diameter at breast height were measured in all plots. In addition, hemispherical photographs were taken to determine leaf area index, understory light availability, and percent canopy openness. Linear mixed-effects models showed significantly higher tree stem density at forest edges, relative to interiors, a pattern reflected by increased stem density, basal area, and aboveground biomass in small diameter trees (≤ 20 cm) growing near edges. No differences in total tree basal area, aboveground biomass, or hemispherical photograph-derived parameters were detected across the forest edge to interior gradient. The recruitment of small diameter trees following edge creation has contributed to the development of dense vegetation at the forest edge and has aided in the maintenance of similar tree basal area and aboveground biomass between edge and interior environments. These data reflect on the robustness of forest edges in Sarapiquí, a characteristic that will likely minimize future detrimental edge effects and promote a number of high-value environmental services in these forests.     

Resistance of Island Rainforest to Invasion by Alien Plants: Influence of Microhabitat and Herbivory on Seedling Performance

Experiments have promise in determining mechanisms by which communities resist invasion. Growth and survivorship of transplanted seedlings of introduced tree species (Leucaena leucocephala, Muntingia calabura, Adenanthera pavonia, and Clausena excavata) were used to assess abiotic (light regime) and biotic resistance (herbivory) to invasion of rainforest on Christmas Island (Indian Ocean). At four sites, seedlings were transplanted into the forest edge along roadside verges and into adjacent intact forest; half were caged to prevent access by the dominant seedling consumer, the red land crab (Gecarcoidea natalis). Red crab densities did not differ between roadside and forest plots. Red crabs initially reduced survivorship of Leucaena in both edge and interior plots but virtually all seedlings in the forest interior were dead after 41 weeks. Survivorship of Muntingia was also initially reduced by crabs in the forest edge, but again, all but one seedling died by the end of the experiment. Seedlings of Adenanthera and Clausena fared much better overall, surviving well in both locations. Red crabs had no overall effect on Adenanthera survival but significantly reduced survival of Clausena in forest plots. For both species, seedling performance was greater in the forest edge than in the forest interior. Red crabs had no effect on height increment for either species; however, for Clausena, red crabs reduced seedling mass in the forest interior. Both Adenanthera and Clausena were able to persist in the intact forest. Clausena is now actively invading intact rainforest, but Adenanthera appears dispersal-limited. Resistance factors in intact forest appear hierarchical: biotic resistance afforded by land crabs can impede establishment of some plant invaders but seedling responses to abiotic factors (e.g., the light regime) largely overwhelm its effect. Together, these two community attributes are likely to restrict the range of plant invaders to a small suite of species that can successfully establish in intact rainforest on the island. However, increased propagule pressure from a variety of shade-tolerant species and further declines in the abundance of the dominant seedling consumer may lead to increasing invasion success in this island rainforest. This revised version was published online in July 2006 with corrections to the Cover Date.     

哀牢山中山湿性常绿阔叶林木质藤本对边缘效应的响应

全球范围内森林片断化现象日益严重。与其他木本植物(乔木和灌木)相比, 木质藤本更趋向于分布在片断化森林的边缘, 因而了解木质藤本对边缘效应的响应对于进一步了解其对森林动态的影响极其必要。本文对哀牢山中山湿性常绿阔叶林林缘到林内环境梯度上木质藤本的变化进行了调查。在形成年龄分别为13年、35年和53年的3种类型的林缘, 设置从林缘向林内连续延伸的长方形样地(20 m × 50 m)各10个(总面积3 ha), 每个样地再划分为5个20 m × 10 m的样方。在每个样方内对胸径≥ 0.2 cm且长度≥ 2.0 m的木质藤本进行了每木调查。在3 ha的林缘样地中共记录到木质藤本植物2,426株, 隶属于14科19属31种。木质藤本的物种丰富度和多度均随距林缘距离的增加而降低, 边缘效应深度在35年林缘的边缘为30 m, 13和53年林缘的边缘则为20 m; 它们的胸高断面积在53年林缘的边缘效应深度为20 m, 但在13和35年林缘的不同距离上差异不显著。木质藤本对边缘效应的响应在物种水平上存在显著差异, 主要呈现正向和中性的响应格局, 包括只分布于林缘的物种, 和从林缘到林内环境梯度上密度逐渐降低的物种; 也有对边缘效应不敏感的物种。典范对应分析(CCA)表明, 林冠开度、边缘形成年龄和土壤水分是决定木质藤本在片断化森林边缘分布的重要影响因子。     

Nucleation-driven regeneration promotes post-fire recovery in a Chilean temperate forest

Nucleation is a successional process in which extant vegetation facilitates seed dispersal and recruitment of other individuals and species around focal points in the landscape, leading to ecosystem recovery. This is an important process in disturbed sites where regeneration is limited by abiotic conditions or restrictive seed dispersal. We investigated forest recovery in a large burned area of evergreen temperate rainforest in southern Chile subjected to seasonal soil waterlogging, and assessed the relevance of nucleation processes in overcoming biotic and physical barriers for tree species regeneration. We measured richness and abundance of woody species in relation to patch size, as well as abiotic factors such as light and soil moisture within and outside patches. We found higher tree regeneration in existing patches than in open areas. We recorded an increase of patch size over time, associated with the increase in number of individuals and tree species. Soils in open areas were waterlogged, especially in winter, while patches were not. Trees in patches also acted as perches, enhancing bird-mediated seed rain. Seeds of fleshy-fruited tree species arrived first at patches and seedlings were more frequent in smaller, younger patches, while the number of seedlings of trees with wind-dispersed seeds increased in larger, older patches. Our study shows that woody species seem incapable of recruiting in open and waterlogged soils and depend strongly on extant vegetation patches to establish. In this fire-disturbed evergreen temperate forest regeneration occurs via nucleation, where new individuals contribute to a centrifugal kind of patch growth.     

Tree Regeneration and Understory Woody Plants Show Diverse Responses to Forest–Pasture Edges in Costa Rica

ABSTRACT Edge effects along tropical forest–pasture margins are thought to cause a shift toward early successional characteristics of the understory forest vegetation. We tested this idea by sampling vegetation at five forest sites in northeast Costa Rica each of which had edges that were established over 20 yr earlier. Four of these sites had been selectively logged. We sampled woody plants >0.2 and ≤1.3 m height in 54 m² within 0.2 ha plots at edges (N=14), and at 150 m (N=11) and 300 m from edges (N=9). Composition and diversity did not vary with edge distance. Abundance of tree regeneration, mainly of canopy and emergent species, increased at edges. Abundance of lianas and slow‐growing tree species did not differ significantly across the sampling locations. Weighted mean wood density varied little, with a reduction at edges for canopy species. Palms were less abundant at edges, but not less species rich. At edges, these plant assemblages maintain many of the characteristics of forest interior vegetation, though the changes observed may indicate ongoing functional change. Degradation of forest–pasture edges is not a universal feature of tropical forest fragmentation, and forests with high rates of natural turnover might have a high capacity to maintain themselves within forest edges alongside pasture.     

Ant colonization and coarse woody debris decomposition in temperate forests

Ants are ubiquitous, abundant and have widespread impacts on ecological communities and ecosystem processes. However, ant effects on coarse woody debris decomposition are unexplored. Several ant species colonize coarse woody debris for nesting, and this puts them in contact with fauna and microbes that utilize coarse woody debris as habitat and food, potentially influencing nutrient cycling and, ultimately, forest productivity. We report results from a field experiment employing 138 artificial ant nests (routed pine blocks) across five locations in southeastern US deciduous forests. We examine the correspondence between ant, termite and wood-eating fungi colonization and variation in coarse woody debris decomposition. After 1 year, nests colonized by ants had 5% more mass than those not colonized. Ant colonization corresponded with significantly less termite- and fungal-mediated decomposition of the nests. Without ants, termites removed 11.5% and fungi removed 4% more wood biomass. Ants, termites and wood-eating fungi all colonized pine nests where temperatures were highest, and ants also preferred higher soil moisture whereas termites and fungi responded negatively to high soil moisture when temperatures were higher. Ants reduce termite colonies through predation, and may inhibit fungi through the secretion of antimicrobial compounds. Our results indicate that interactions between forest understory ants, termites and fungi may influence the rate of coarse woody debris decomposition—biotic interactions that potentially influence forest structure and function.     

Predation on artificial avian nests is higher in forests bordering small anthropogenic openings

Habitat edges alter the diversity of avian communities and are often associated with higher rates of nest predation. However, most previous studies on habitat edges have been conducted along long linear corridors or at the transition between large field and forest patches in agricultural systems. Less is known about predation rates when the habitat edge is the result of a small interior forest opening. We assessed predation rates on artificial nests mimicking ground and shrub nesters in Northern Michigan forests perforated by small clearings used previously for oil and gas extraction. Nests were placed at varying distances from the edges of these clearings, and in similar spatial arrangements within unfragmented interior forest plots. Predation rates increased in forests near edges, but significant impacts were limited to shrub nests. Markings on predated clay eggs indicated that the type of predation also differed. Scratch marks were the most prevalent egg indentation, but eggs with poked holes were twice as common near the forest edge. The increase in the number of poked eggs suggests that a higher density of avian predators occurred in forests near an edge. Predation rates at forest edges did not vary by distance from the forest edge. Surveys of the avian community revealed differences between edge and interior forests: American Crows Corvus brachyrhynchos and Blue Jays Cyanocitta cristata, two species known to predate bird nests, were more common near edges. Our results suggest that small forest openings alter the avian community and may adversely impact reproductive output in some species. If the alteration of these processes results in population‐level impacts, small forest perforations should be avoided when possible and reforestation of abandoned well‐pads should be encouraged.