Native Ground Research Articles

Planting native trees in degraded grassy woodland does not restore species composition

SummaryRestoration of degraded former Cumberland Plain Woodland by planting of native trees and shrubs was undertaken by Greening Australia (NSW) on the Cumberland Plain, west of Sydney, Australia, from the mid‐1990s. Our study examined the success of this restoration in stands of two ages using species composition as the criterion. The starting point (pasture) and the target (reference woodland) were sampled to document the extent of progress of species composition from pasture through young (3–5 years) and old (9–11 years) restoration stands to reference woodland across three sites at two surveys. Comparisons showed restored stands of both ages differed significantly from pasture, and from each other, showing decreasing similarity between the restoration stands and pasture at all sites. Despite this, species composition in restored stands at all three sites was still significantly different from reference sites, showing that none had achieved the target reference state after 11 years. The trajectory of restored sites between the two surveys was not towards the reference state. Restoration resulted in the establishment of 20 (71%) of the planted species. Recruits from five planted species were found. A further 40 unplanted native ground layer species were found in restoration. Structurally, tree cover increased with time since restoration and was higher in the restored sites. Ground cover, which was very high in pasture was lower in some restored sites. The majority of the unplanted native species were resprouters, and their presence in the above‐ground vegetation was most likely by vegetative resprouting from the bud‐and‐tuber bank as ground cover was lower with the increase in tree cover and shade. Tree and shrub planting by itself has not yet progressed the restored areas to the species composition of reference sites. Additional tools will be needed to assist restoration, specifically the addition of re‐seeder native plants not able to persist through vegetative resprouting after restoration. Measures to control the burden of weeds present in the pasture seed bank are also required.

A Decoupled Buckling Failure Analysis of Buried Steel Pipeline Subjected to the Strike-Slip Fault

Over the past few years, there has been an increased focus on offshore pipeline safety due to the development of offshore oil and gas resources. Both onshore and offshore pipelines may face significant geological hazards resulting from active faults. Pre-excavated soil can be used as backfill for trenches to prevent major pipeline deformations. Since these backfill materials have been heavily remolded, they are softer than the native soil. Therefore, the difference in shear strength between the backfill and native ground may have an effect on the interaction between the pipeline and the backfill. In this paper, the pipeline–backfill–trench interaction is investigated using a hybrid beam–spring model. The P-Y curves obtained from CEL analysis are incorporated into a 3D beam–spring model to analyze the pipeline’s response to lateral strike-slip faults. Additionally, the nonlinearity of pipeline materials is considered to study pipeline failure modes under strike-slip fault movements. A series of parametric studies were conducted to explore the effects of fault intersection angle, pipe diameter, buried depth of the pipe, and soil conditions on the failure modes of buckling pipelines. The developed method can be used to analyze and assess pipeline–backfill–trench interaction when subjected to strike-slip fault displacements.

A step to disentangle diversity patterns in Uruguayan grasslands: Climatic seasonality, novel land‐uses, and landscape context drive diversity of ground flora

AbstractSouth American grasslands contain extraordinary biodiversity and play a central role in the subsistence of regional agroecosystems. In recent decades, afforestation, followed by the soybean planting boom, have led to drastic land‐use changes at the expense of grasslands. Impacts on local biodiversity have remained understudied. We explored the taxonomic richness and ß‐diversity of plants of ground layer (excluding trees and shrubs) at different land uses, its interplay at regional scale with environmental heterogeneity, and at local scale with novel land cover types and landscape configurations. We conducted correlation, principal component, NDMS, and SDR analysis to explore variation of taxonomic richness, richness difference, replacement, and similarity of ground flora as response to environmental filters and land use change across Uruguay. We surveyed 160 plots distributed in 10 land cover types, that is, closed and open native forests, different grasslands, crops, orchards, and timber plantations. We observed overlaying regional patterns driven by seasonality of temperature and precipitation, and land cover shaping taxonomic richness at local scale. Landscape configuration affects diversity patterns of native ground flora, which seems to be sustained mainly by the “old growth grassland” species pool. Taxonomic richness of native species decreases with an increase of distance to grassland. Crops and grasslands harbor a higher number of native species in the ground flora than native forests and timber plantations. The introduction of exotics is driven mostly by crops or highly modified pastures. Diversity patterns only partially reflect the ecoregion concept. Expanding the perspective from conservation in purely natural ecosystems to measures conserving species richness in human‐modified landscapes is a powerful tool against species loss in the Anthropocene.

Peace and Friendship: An Alternative History of the American West by Stephen Aron (review)

Reviewed by: Peace and Friendship: An Alternative History of the American West by Stephen Aron Eran Zelnik (bio) Keywords Western history, Alternative history, Daniel Boone, Indigenous people, Lewis and Clark, Oregon Trail, Dodge City Peace and Friendship: An Alternative History of the American West. By Stephen Aron. (New York: Oxford University Press, 2022. Pp. 320. Cloth, $29.95.) Alternative histories of the west that attempt to complicate, or flat out contradict, declension narratives have been at a premium for several decades [End Page 349] now. Perhaps most famously, after Richard White wrote The Roots of Dependency: Subsistence, Environment and Social Change among Choctaws, Pawnees, and Navajos (Lincoln, NE, 1983), in his next book he sought to frustrate this account of Native American decline, and the result was one of the most influential histories of the west, The Middle Ground: Indians, Empires, and Republics in the Great Lakes Region, 1650–1815 (New York, 1991). In recent decades, perhaps the most noteworthy histories in this vein were Pekka Hämäläinen's Comanche Empire (New Haven, CT, 2009) and Kathleen DuVal's The Native Ground: Indians and Colonists in the Heart of the Continent (Philadelphia, 2006), which related narratives of indigenous strength and dominance over European and other Native adversaries. In Peace and Friendship: An Alternative History of the American West, Stephen Aron brings his deep familiarity with western history to tell a story that differs markedly from traditional narratives of "bloody ethnic cleansings and even genocides" (4). Yet, this study is something of an inversion of DuVal and Hämäläinen's stories of Native power. Instead, Aron "seeks out sites and situations in which colonialism wore a different face and relations between Indians, settlers, and states deviated (for a time) from the monolithic logic of elimination" (4). Even as it attempts to retrieve episodes that challenge the violent framing of most western histories, Peace and Friendship also steers clear of "wishtories": fictionalized "stories about the past" that "cater to contemporary yearnings," such as Disney's Pocahontas or any other "'kumbaya' version of colonialism" (6), for that matter. To do so, Aron takes us on a stroll across the continent that begins with Daniel Boone; Chapter 1 takes place in Revolutionary Kentucky, while Chapter 2 follows Boone down the Ohio River to the region surrounding Apple Creek. Here around the turn of the eighteenth century, Shawnees and Anglo settlers like Boone led something of a peaceful coexistence. This is probably Aron's strongest chapter, in which he provides a good amount of compelling and relatively less familiar evidence regarding the genial relationships fostered between Anglos and Shawnees under Spanish auspices. In Chapter 4, however, we learn that these relationships soured by the War of 1812. Chapter 3 follows Lewis and Clark's famous Corps of Discovery expedition that set out from St. Louis in 1804, while Chapter 5 examines the relationships between Great Plains Indians and settlers on the so-called Oregon Trail from the 1820s through the 1850s. In both cases, Aron sorts [End Page 350] out myth from reality, contending, for example, with the legacy of the famous computer game The Oregon Trail in shaping the memory of the period. Lastly, Chapter 6 explores the history of Dodge City during its heyday in the second half of the nineteenth century, first as a depot for Buffalo hunters, and later as the end destination of cowboys driving cattle up from Texas. As before, Aron contends that violence, in this supposedly notorious hub of gunslingers, was not as ubiquitous as mythologies of the west would have us believe. Aron's study is an intriguing proposition, while his deep familiarity with the materials and his easy and nimble prose make the book an engrossing read. However, by prioritizing narrative flow and a cast of familiar characters and episodes from American history, the book runs into two considerable shortcomings. First—and this is a pitfall many historians (including myself) often fall into—too much of the narrative conveys the historical context in which such fleeting moments of "peace and friendship" first emerged and then disappeared. As a result, far too little of the book relates episodes and evidence of peace and...

Native vegetation structure, landscape features and climate shape non‐native plant richness and cover in New Zealand native shrublands

AbstractAimStudies investigating the determinants of plant invasions rarely examine multiple factors and often only focus on the role played by native plant species richness. By contrast, we explored how vegetation structure, landscape features and climate shape non‐native plant invasions across New Zealand in mānuka and kānuka shrublands.LocationNew Zealand.MethodWe based our analysis on 247 permanent 20 × 20‐m plots distributed across New Zealand surveyed between 2009 and 2014. We calculated native plant species richness and cumulative cover at ground, understorey and canopy tiers. We examined non‐native species richness and mean species ground cover in relation to vegetation structure (native richness and cumulative cover), landscape features (proportion of adjacent anthropogenic land cover, distance to nearest road or river) and climate. We used generalized additive models (GAM) to assess which variables had greatest importance in determining non‐native richness and mean ground cover and whether these variables had a similar effect on native species in the ground tier.ResultsA positive relationship between native and non‐native plant species richness was not due to their similar responses to the variables examined in this study. Higher native canopy richness resulted in lower non‐native richness and mean ground cover, whereas higher native ground richness was associated with higher native canopy richness. Non‐native richness and mean ground cover increased with the proportion of adjacent anthropogenic land cover, whereas for native richness and mean ground cover, this relationship was negative. Non‐native richness increased in drier areas, while native richness was more influenced by temperature.Main ConclusionsAdjacent anthropogenic land cover seems to not only facilitate non‐native species arrival by being a source of propagules but also aids their establishment as a result of fragmentation. Our results highlight the importance of examining both cover and richness in different vegetation tiers to better understand non‐native plant invasions.

Peptide Bond of Aqueous Dipeptides Is Resilient to Deep Ultraviolet Irradiation

The susceptibility of aqueous dipeptides to photodissociation by deep ultraviolet irradiation is studied by femtosecond spectroscopy supported by density functional theory calculations. The primary photodynamics of the aqueous dipeptides of glycyl-glycine (gly-gly), alalyl-alanine (ala-ala), and glycyl-alanine (gly-ala) show that upon photoexcitation at a wavelength of 200 nm, about 10% of the excited dipeptides dissociate by decarboxylation within 100 ps, while the rest of the dipeptides return to their native ground state. Accordingly, the vast majority of the excited dipeptides withstand the deep ultraviolet excitation. In those relatively few cases, where excitation leads to dissociation, the measurements show that deep ultraviolet irradiation breaks the Cα-C bond rather than the peptide bond. The peptide bond is thereby left intact, and the decarboxylated dipeptide moiety is open to subsequent reactions. The experiments indicate that the low photodissociation yield and in particular the resilience of the peptide bond to dissociation are due to rapid internal conversion from the excited state to the ground state, followed by efficient vibrational relaxation facilitated by intramolecular coupling among the carbonate and amide modes. Thus, the entire process of internal conversion and vibrational relaxation to thermal equilibrium on the dipeptide ground state occurs on a time scale of less than 2 ps.

Plant defensins as a model to study the thermostability of surface hydrophobic clusters: The Pisum sativum defensin 2 (Psd2)

Plant defensins (PDs) display a CSαβ-fold that lacks a canonical hydrophobic core. They display almost all hydrophobic residues on the protein surface. The exposed hydrophobic residues form surface clusters stabilized by the vicinity of hydrophilic residues and the hydration shell. Here, we used Psd2 as a model to study the formation and stabilization of these local foldons named surface hydrophobic clusters (SHC). We characterized the temperature dependence of 15N CPMG relaxation dispersion profiles to describe the complex dynamics of Psd2 and indirectly study the thermodynamics of SHCs in PDs. We show a correlation between residues undergoing conformational exchange and the SHCs. Chemical shift changes between the native ground state and the first thermally accessible excited state enabled us to map the major conformational changes in Psd2 conformational equilibrium. The observation of a cold-driven excited state revealed that SHCs are stabilized by hydrophobic contacts, which are exposed at low temperatures, leading to a favorable decrease in enthalpy compensated by an unfavorable entropy reduction. At higher temperatures, we detected another excited conformer that may play a role in membrane-specific interaction, as previously described for other defensins.

Assessment of the Response of Trenched–Backfilled Pipelines to Strike-Slip Faults: An Analytical Approach

Trenched pipelines may experience significant lateral displacement due to natural geohazards such as strike slip-fault movements, landslides, etc. Using pre-excavated soil to backfill trenches is a cost-effective option to protect pipelines against large deformations. These backfilling materials are heavily remolded and therefore softer than the native ground. Therefore, the shear strength difference between the backfill and native ground may affect the pipeline–backfill–trench interaction and the failure mechanism of the surrounding soil. By assuming a simplified uniform soil domain, the influence of softer pre-excavated backfilling material on the pipeline–backfill–trench interaction is neglected in the analytical methods that are usually used in the structural health monitoring of buried pipelines. In this study, the effects of trenching and backfilling were incorporated into an analytical solution for a fast assessment of the pipeline response at the early stages of engineering design projects and structural health monitoring. In comparison with other methods, this methodology provides a convenient and efficient method for computing pipeline strain and deflection curves in geohazardous regions.

THE STABILIZED DUNES: A PILOT STUDY ON THE EFFECT OF ACACIA TORTILIS ON GROUND VEGETATION, FROM THAR DESERT, INDIA

In modern days, sand dune stabilization works are very common in desert areas globally. The purpose is multifaceted; developmental needs, soil moisture conservation works, and prevention of desert spread being the main among them. In the Indian state of Rajasthan, the same works have been ongoing for a long in the Thar desert, primarily by the forest department. This study was aimed as a non replicated administrative study, which has reflected on the possible correlation between the stabilization work by afforestation and gradual loss of native shrub species of desert ecosystem as found from the pilot sites. The preliminary findings of this study were then verified against previous research and findings in other arid regions of the world. Simple counting of standing tree and shrub species was done from 1 sq. m. sample plots of both forest department plantation sites and non-forest land areas. It was found that area with matured grown Acacia tortilis has less ground coverage than other areas. Arid ecosystem has unique survival adaptations, the fast growth of an introduced foreign species impacting the native ground cover can be due to multiple ecological reasons. A much broader replicated study is necessary to ascertain this fact and thereby take necessary measures for preserving both the desert ecosystem and enhance the sand stabilization works

THE LANDS WERE NOT EMPTY

THE LANDS WERE NOT EMPTY

Low‐intensity cattle grazing is better than cattle exclusion to drive secondary savannas toward the features of native Cerrado vegetation

AbstractAlthough livestock have been historically associated with land conversion and biodiversity loss, well‐managed cattle grazing has been reported to contribute to conservation of open ecosystems. Knowing the balance between positive and negative effects of livestock (presence or exclusion) on different ecosystems is, therefore, crucial to support management decisions. We conducted an experiment in a secondary savanna with exotic grasses, used as pasture, to assess the effect of cattle presence in low density and cattle exclusion (in paired plots) on the trajectory of these ecosystems. Richness, composition and structure of the woody community, and exotic grass cover and biomass were compared between treatments in the beginning of the experiment and after 7 years. At the end of the experiment, we also compared composition, richness, and density of the native ground layer. We verified that (a) cattle exclusion accelerates the undesirable woody encroachment, changes the species composition and leads to huge grass fuel accumulation, while (b) cattle grazing/browsing hinders changes in savanna structure and composition and reduces the exotic grass cover and biomass, thus favoring native herbaceous plants. By decreasing the grass biomass, cattle grazing also reduces the system flammability and, therefore, the risk and intensity of wildfires. Together, the positive effects of cattle presence and the negative effects of cattle exclusion lead to the conclusion that cattle should be maintained in these systems. Low‐intensity cattle grazing limits woody and exotic grass invasion, improves native forb biodiversity, and help to maintain composition and structural features of secondary savannas of the Cerrado.Abstract in Portuguese is available with online material

Effects of competition and habitat heterogeneity on native‐exotic plant richness relationships across spatial scales

AbstractAimThe biotic resistance hypothesis posits that greater native species richness limits invasions of exotic species. However, negative native‐exotic richness relationships (NERRs) may reverse with increasing spatial scale, seemingly refuting the hypothesis. Here, we explore the effects of species competitive interactions, environmental factors, habitat heterogeneity and vertical vegetation tiers on the NERRs across spatial scales in native forests.LocationNew Zealand.MethodsWe combined vegetation, land cover and climate data to predict exotic richness from native richness at different vertical tiers (ground to canopy), land cover, plant competition (tree basal area, native ground cover), mean annual temperature and total rainfall. We considered four spatial scales, from single 20 × 20 m plots on an 8‐km grid to groups of plots across grids up to 128 km. Habitat heterogeneity was measured using the variance of climatic conditions among plots within a group.ResultsA negative native tree‐exotic richness relationship (NTERR) was observed at plot level but reversed with increasing spatial scale. Species competitive interactions showed a negative relationship with exotic richness at small/intermediate scales (≤32 km). Rainfall and temperature heterogeneity contributed to the positive NTERR at the largest scale. Adjacent exotic grassland cover had a positive relationship with exotic richness across all scales but did not prevent the NTERR from reversing.Main conclusionsOur analysis shows the importance of considering vegetation structure and adjacent land covers, along with spatial heterogeneity and climatic factors, when testing the biotic resistance hypothesis in forest ecosystems. There is a clear indication that biotic resistance is primarily driven by native trees in the overstorey, probably by limiting resources available to ground tier plants. The results support the notion that the NERR is driven by competitive interspecific interactions at small spatial scales and by habitat heterogeneity at larger scales.

Where Caciques and Mapmakers Met: Border Making in Eighteenth-Century South America by Jeffrey Alan Erbig Jr.

Reviewed by: Where Caciques and Mapmakers Met: Border Making in Eighteenth-Century South America by Jeffrey Alan Erbig Jr. Santiago Muñoz-Arbeláez (bio) Where Caciques and Mapmakers Met: Border Making in Eighteenth-Century South America jeffrey alan erbig jr. University of North Carolina Press, 2020 280 pp. The lowland plains of Rio de la Plata in South America, along the territories of modern Uruguay, northern Argentina, and southern Brazil, were borderlands in the eighteenth century: a terrain of shifting distributions of power between Jesuit-Guaraní missions, Portuguese and Spanish cities and ranches, and, importantly, the settlements of a diverse set of Indigenous peoples whose names were recorded as Bohanes, Charrúas, Guenoas, Minuanes, Yaros, and others. Europeans called these last encampments tolderías, from the word toldo (tent). In his book Where Caciques and Mapmakers Met: Border Making in Eighteenth-Century South America, Jeffrey Alan Erbig Jr. argues that while Rio de la Plata in the eighteenth century was an Indigenous area dominated by tolderías, power shifted toward the control of European empires during the century, as the borderlands were replaced by agreed-upon imperial borderlines between the Spanish and the Portuguese. In many ways, this process took place in maps. The book is a deep exploration of the shifts of Indigenous and European power by studying eighteenth-century mapmaking and using current-day mapping technologies (and specifically Geographic Information Systems) as a method. The plains of La Plata were crisscrossed by rivers and small hills, with abundant feral livestock. The missions, Spanish and Portuguese settlements, and tolderías all relied on cattle herding that spread over ample, overlapping territories in seasonal migrations. In the eighteenth century, the founding of the Portuguese city Colônia do Sacramento, together with an increasing Spanish desire for the cattle-derived products like hides or jerky (this last product specifically to feed enslaved plantations in the Caribbean), triggered disputes over imperial sovereignty and led to the development of more concrete lines of demarcation between the two empires. Erbig shows that throughout the century a transition from borderlands to borderlines shifted control away from tolderías to the Spanish and Portuguese. After the 1750 Treaty of Madrid and the 1777 Treaty of San [End Page 605] Idelfonso—which defined a ten-thousand-mile boundary between Brazil and Spanish America—the Portuguese and the Spanish designed joint ventures to establish those boundaries. These expeditions traveled through territories commanded by tolderías. Despite the efforts of the Spanish to "reduce" them to fixed settlements to live under the surveillance of Spanish friars and officials, the tolderías maintained their autonomy and dominated the landscape. It was Native ground, mastered by a series of Indigenous people that the Spanish and Portuguese officers did not know well, could not name accurately, and could describe only through a vague term that alluded to the structure of their mobile homes. European cartographers paid taxes to cross and to lodge on Indigenous ground. Yet the maps they produced emphatically did not include the presence of those who governed the territory. Instead, they created clear-cut lines between the Spanish and the Portuguese. These acts of erasure were the most basic expression of colonialism. In the Spanish and Portuguese colonialist rationale, the mobile tolderías could not be legitimate, sovereign polities. The tolderías were understood as barbarians, relics of an earlier stage of human development, left out of maps, and excluded from the negotiation tables where the interimperial treaties were outlined and the border lines were drawn. The map, heavily involved in colonialism, ratified who was seen as a legitimate sovereign nation. I see this very insight into the silence and violence of the map as one of the book's main contributions. The book explores even further the complex relation between the map and the territory. Even though dismissed from European legal treaties and silenced in the maps, the tolderías maintained the actual control over much of La Plata. The Spanish tried to enforce their sovereignty by removing tolderías from what they believed to be their territory; the Portuguese made pacts with caciques (the leaders of the tolderías) to try to get some real control...

An innovative temporary escape ramp for deer and other wildlife

Concrete-lined water conveyance canals can be a significant source of mortality for ungulates and other wildlife, which can drown or become entrapped. Various types of wildlife escape structures have been deployed in canals with limited success. From 2011 to 2018, we used camera traps to monitor mule deer (Odocoileus hemionus) use of three different temporary wildlife escape structure designs with the goal of developing an effective escape structure for fawns. We monitored three to five locations at a hydroelectric water conveyance canal, operated by Pacific Gas and Electric Company in the foothills of Central California on the Sierra National Forest, in which trapped fawns had been detected previously during the maintenance period when the canal was dry. Mule deer activity and ramp use varied by year. During the monitoring period, deer were detected in the canal in all years except 2016 and 2017. Fawns and adults used the temporary escape structures to exit the canal in four of these years and 50% of mule deer detections showed ramp use overall. No deer were detected using the escape structures until jute netting and debris were added to the surface of the escape ramps in the third monitoring year. Prior to this modification, fawns were detected trapped in the canal investigating the ramps, but not using them to exit the canal. Deer may be more likely to utilize ramps covered with materials that mimic native ground cover. Seven other wildlife species were detected entering and exiting using the ramps with a general increase in use over years. Our temporary escape ramp design for small canals, when dry, appears to be novel and may be applicable in other areas. When compared to fencing or covering the canal, it is a relatively low-cost solution to reduce animal entrapment.

The use of state‐and‐transition models in assessing management success

AbstractState‐and‐transition models (STM) are valuable tools that aid understanding and management of ecosystems. There also is potential for STMs to be used as a framework to assess whether management actions are achieving desired conservation objectives. However, few published examples exist where STMs have been used in this way. Using high‐quality empirical field data collected in endangered temperate woodlands across a 6‐year period, we explore whether a Box Gum Grassy Woodland STM employed in an Australian agri‐environment scheme can be used to assess whether management interventions are achieving an improvement in woodland Condition State. We found there was insufficient contextual information in the STM to facilitate its robust use as a framework for assessing whether management interventions were achieving conservation outcomes in Box Gum Grassy Woodlands. Weather was a key driver influencing management effectiveness, but its effects were absent from the STM, as were probabilities and time frames for transitions between Condition States. The deficiencies in the STM may preclude accurate conclusions about the effectiveness of the program. Given the influence of weather on the system, longer time frames are required to adequately assess the influence of management on key variables (e.g., native plant richness, native ground cover) underpinning the STM. This case study provides opportunities to understand the potential implications of using insufficiently contextualized STMs as frameworks for assessing whether management actions are achieving desired conservation objectives. It also provides opportunities to learn from what went wrong. To this end, based on our findings, we provide practical recommendations (applicable beyond our case study system) for improving the construction and implementation of STMs for the purposes of evaluating the success of management interventions in ecological restoration and conservation programs.

Comparison of the Particulate Matter Removal Capacity of 11 Herbaceous Landscape Plants

Background and objective Particulate matter (PM) has a fatal effect on health. There have been many studies on the use of plants such as trees and shrubs as eco-friendly and sustainable biofilter for the removal of PM. In forming more green space, ground cover plants play an important role in multi-layered planting. This study was conducted to investigate the ability of plants to reduce PM, targeting Korean native ground cover plants with high availability in urban green spaces. Methods For 4 species of Asteraceae, 4 species of Liliaceae, and 3 species of Rosaceae, one species of plants at a time were placed in an acrylic chamber (800 × 800 × 1000 mm, L × W × H) modeling an indoor space. After the injection of PM, the amount of PM remaining in the chamber over time was investigated. Results For all three types of PM (PM10, PM2.5, PM1), significant difference occurred in the amount of PM remaining between plant species after 1 hour in the Liliaceae chamber, 3 hours in the Asteraceae chamber, and 5 hours in the Rosaceae chamber. With Liliaceae, the leaf area and the amount of PM remaining in the chamber showed a negative (−) correlation. With the Asteraceae and Rosaceae, there was a weak negative correlation between the leaf area and the amount of PM remaining in the chamber. Conclusion When using ground cover plants as a biofilter to remove PM, it is considered effective to select a species with a large total leaf area, especially for Liliaceae.

Ground cover and native ant predation influence survival of metamorphic amphibians in a southeastern pine savanna undergoing restoration

Longleaf pine savannas historically supported abundant ground cover maintained by frequent fire but little other disturbance. Ground cover creates microclimates with lower temperatures, higher humidity, and increased soil moisture that may benefit wildlife, particularly small vertebrates such as amphibians. Today, most historical pine savannas have had extensive soil disturbance and altered fire regimes resulting in reduced ground cover and altered soil fauna communities including predatory invertebrates. We used a factorial terrestrial cage study to test the effects of native wiregrass (Aristida spp.) cover and the exclusion of a native predatory ant (Dorymyrmex smithi) on the survival of post‐metamorphic Ornate chorus frogs (Pseudacris ornata) and Gopher frogs (Rana capito). Although we were unable to achieve full ant exclusion, ant reduction in exclusion treatments and plant cover had an interactive effect on metamorph survival. Ant exclusion tended to increase Gopher frog survival and this effect was more pronounced when wiregrass was present. Within ant treatments, survival of Gopher frogs increased slightly with increasing wiregrass cover. Ornate chorus frogs had a high probability of survival (>95%) in all ant exclusion treatments regardless of wiregrass cover; however, in treatments without ant exclusion, survival increased with increasing wiregrass cover. Our results demonstrate that high abundances of a native ant species and low coverage of native wiregrass, which are legacies of historical soil disturbance and altered fire regimes, interact to elevate mortality of juvenile amphibians. Minimizing soil disturbance and restoring native ground cover are likely important for amphibian habitat management within historical southeastern pine savannas.

Where Caciques and Mapmakers Met: Border Making in Eighteenth-Century South America

Where Caciques and Mapmakers Met: Border Making in Eighteenth-Century South America

Comparative Meta-analysis Effects of Nonnative Ants (Hymenoptera: Formicidae), Ground Beetles (Coleoptera: Carabidae), and Bark and Ambrosia Beetles (Coleoptera: Curculionidae) on Native Confamilials.

Nonnative species often transform local communities to the detriment of native species. Much of the existing invasion ecology research focuses on the effects of a few extremely impactful species, and it is less clear how nonnative species which are not causing economic or ecological impacts alter closely related natives at risk of being displaced. Filling these knowledge gaps is critical because consequences of nonnative species are likely to vary depending on taxonomic scale, functional trait, and spatial or temporal niche. We conducted a meta-analysis to evaluate how biodiversity of native Formicidae (ants), Carabidae (ground beetles), and Scolytinae (bark and ambrosia beetles) species changes across a gradient of pressure from nonnative confamilials. We calculated Hill numbers for each group from data presented in literature and correlated native diversity metrics to proportion of nonnative species. Species richness of native ants was significantly negatively correlated with proportions of nonnative ants, whereas bark and ambrosia beetle metrics showed a nonsignificant negative correlation. Nonnative ground beetles had neutral effects on diversity of native ground beetles. Resulting contrasting patterns of invasive species effects on natives suggest complex biotic and abiotic factors driving effects of nonnative species in these groups. Our results suggest that a few extreme examples (e.g., red imported fire ants) drive most of the changes seen in native arthropod communities. To accurately assess impacts of invaders on native arthropod diversity, baseline data are needed, and community analyses must consider diverse functional traits of native taxa and improve the depth and breadth of community sampling.

Experimental study of trench effect on lateral failure mechanisms around the pipeline buried in clay

Pipelines are usually trenched and backfilled using the pre-excavated soil as cost-effective protection against the environmental, constructional, and operational loads. The design of buried pipelines for potential lateral displacements caused by ground movements is a challenging aspect that is usually simplified by assuming a uniform soil stratum. However, the remoulded backfilling material and its lower stiffness compared with the native ground can significantly affect the soil failure mechanisms and the mobilized lateral soil resistance. In this study, a qualitative experimental assessment was conducted to investigate the lateral pipeline-backfill-trench interaction effect on soil failure mechanisms and the resultant lateral soil resistance in shallow and deep burial conditions. Particle image velocimetry (PIV) was used to observe the interactive soil displacements directly. The partially drained condition was adopted to magnify the pipeline-backfill-trench interaction effects. It was observed that the interactive effects of pipeline, backfill, and trench precede their individual shear strengths and reduce the ultimate soil resistance. Also, the study revealed the significance of the pipeline/trenchbed interaction in the mobilization of the lateral soil resistance and several other mechanisms not yet addressed in the literature. As a result, several new research avenues were identified, and the ground was prepared for proposing cost-effective solutions to improve the prediction of the lateral response of buried pipelines in the near future.