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Abstract Most canopy insect research takes place in tropical forests, where communities are highly vertically stratified. However, temperate forest canopies also provide critical resources to many species and are under intense pressure from global change drivers. The relative lack of knowledge regarding temperate canopy insect ecology impedes our forest management and conservation decisions such that we may be losing temperate canopy biodiversity before we know it exists.We directly compared ant diversity and community composition on the ground and in the tree canopy of North American temperate deciduous forests for the first time. We also evaluated two canopy sampling methods—baits and hand collections.We collected 34 ant species from 102 trees across seven sites. Ant diversity was greater on the ground than in the canopy, and species turnover created distinct communities across vertical strata. Only 12% of species were exclusively arboreal, but 47% were collected in both strata, indicating the canopy is an important resource for temperate ants, even if they are not restricted there.Baiting and hand‐collecting recovered similar species richness, but whether baits captured a subset of hand‐collected species or a unique assemblage was site‐dependent. Nevertheless, we suggest that these methods are most effective in conjunction.Hand collection allowed us to document arboreal nests of 10 species, including the invasive needle ant,Brachyponera chinensis, which was previously thought to be strictly terrestrial.Our results emphasise the importance of including the canopy in temperate forest ecology and conservation assessments.
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Aridity and forest age mediate landscape scale patterns of tropical forest resistance to cyclonic storms
Abstract Cyclonic storms, or hurricanes, are expected to intensify as ocean heat energy rises due to climate change. Ecological theory suggests that tropical forest resistance to hurricanes should increase with forest age and wood density. However, most data on hurricane effects on tropical forests come from a limited number of well‐studied long‐term monitoring sites, restricting our capacity to evaluate the resistance of tropical forests to hurricanes across broad environmental gradients.In this study, we assessed whether forest age and aridity mediate the effects of hurricanes Irma and Maria in Puerto Rico, Vieques and Culebra islands. We leveraged functional trait data for 410 tree species, remotely sensed measurements of canopy height and cover, along with data on forest stand characteristics of 180 of 338 forest monitoring plots, each covering an area of 0.067 ha. The plots represent a broad mean annual precipitation (MAP) gradient from 701 to 4598 mm and a complex mosaic of forest age from 5 to around 85 years since deforestation.Hurricanes resulted in a 25% increase in basal area mortality rates, a 45% decrease in canopy height and a 21% reduction in canopy cover. These effects intensified with forest age, even after considering proximity to the hurricane path. The links between forest age and hurricane disturbances were likely due the prevalence of tall canopies.Tall forest canopies were strongly linked with low community‐weighted wood density (WD). These characteristics were on average more common in moist and wet forests (MAP >1250 mm). Conversely, dry forests were dominated by short species with high wood density (WD > 0.6 g cm−3) and did not show significant increases in basal area mortality rates after the hurricanes.Synthesis. Our findings show that selection towards drought‐tolerant traits across aridity gradients, such as short stature and dense wood, enhances resistance to hurricanes. However, forest age modulated responses to hurricanes, with older forests being less resistant across the islands. This evidence highlights the importance of considering the intricate links between ecological succession and plant function when forecasting tropical forests’ responses to increasingly strong hurricanes.
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- PAR ID:
- 10577245
- Publisher / Repository:
- Journal of Ecology
- Date Published:
- Journal Name:
- Journal of Ecology
- Volume:
- 113
- Issue:
- 1
- ISSN:
- 0022-0477
- Page Range / eLocation ID:
- 53 to 67
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/1365-2745.14437
