This open access book describes the serious threat of invasive species to native ecosystems. Invasive species have caused and will continue to cause enormous ecological and economic damage with ever ...increasing world trade. This multi-disciplinary book, written by over 100 national experts, presents the latest research on a wide range of natural science and social science fields that explore the ecology, impacts, and practical tools for management of invasive species. It covers species of all taxonomic groups from insects and pathogens, to plants, vertebrates, and aquatic organisms that impact a diversity of habitats in forests, rangelands and grasslands of the United States. It is well-illustrated, provides summaries of the most important invasive species and issues impacting all regions of the country, and includes a comprehensive primary reference list for each topic. This scientific synthesis provides the cultural, economic, scientific and social context for addressing environmental challenges posed by invasive species and will be a valuable resource for scholars, policy makers, natural resource managers and practitioners.
Future expected changes in climate and human activity threaten many riparian habitats, particularly in the southwestern U.S. Using Maximum Entropy (MaxEnt3.3.3) modeling, we characterized habitat ...relationships and generated spatial predictions of habitat suitability for the Lucy's warbler (Oreothlypis luciae), the Southwestern willow flycatcher (Empidonax traillii extimus) and the Western yellow-billed cuckoo (Coccyzus americanus). Our goal was to provide site- and species-specific information that can be used by managers to identify areas for habitat conservation and/or restoration along the Rio Grande in New Mexico. We created models of suitable habitat for each species based on collection and survey samples and climate, biophysical, and vegetation data. We projected habitat suitability under future climates by applying these models to conditions generated from three climate models for 2030, 2060 and 2090. By comparing current and future distributions, we identified how habitats are likely to change as a result of changing climate and the consequences of those changes for these bird species. We also examined whether land ownership of high value sites shifts under changing climate conditions. Habitat suitability models performed well. Biophysical characteristics were more important that climate conditions for predicting habitat suitability with distance to water being the single most important predictor. Climate, though less important, was still influential and led to declines of suitable habitat of more than 60% by 2090. For all species, suitable habitat tended to shrink over time within the study area leaving a few core areas of high importance. Overall, climate changes will increase habitat fragmentation and reduce breeding habitat patch size. The best strategy for conserving bird species within the Rio Grande will include measures to maintain and restore critical habitat refugia. This study provides an example of a presence-only habitat model that can be used to inform the management of species at intermediate scales.
Ecosystem sustainability is the basis for life, economic and social sustainability. The energy metabolism of an ecosystem has long been a focus area in the scientific community because it determines ...the productivity, sustainability and development of ecosystem. This study applied emergy analysis to explore the metabolism of maize ecosystems under different environmental conditions; to investigate its energy input, environmental pressure and sustainability; and to understand the maintenance mechanism of the general ecosystem based on the China statistical data of 2014. Results showed that the sum of renewable natural resources ranged from 0.62 × 1014 seJ/ha in Xinjiang to 6.34 × 1014 seJ/ha in Guangxi; the sum of nonrenewable natural resources ranged from 3.95 × 1014 seJ/ha for Henan to 9.46 × 1014 seJ/ha for Jilin; the sum of purchased renewable resources ranged from 2.97 × 1014 seJ/ha for Heilongjiang to 26.14 × 1014 seJ/ha for Gansu; the sum of purchased nonrenewable resources ranged from 14.89 × 1014 seJ/ha in Sichuan to 33.00 × 1014 seJ/ha in Gansu. In addition, the environmental loading ratio in Xinjiang was the highest, followed by Ningxia (25.92), Gansu (24.77), Inner Mongolia (23.15), the lower values were 4.48, 4.21 and 4.00 for Guizhou, Chongqing and Guangxi, respectively; similarly, the emergy sustainability index in the provinces of southern China were higher than those in northwest of China. Above all, maize ecosystem is developed with a stronger competitive ability than other agricultural ecosystems, especially in the southern region of China, but also has a high environmental loading ratio. Furthermore, the proportion of natural and purchased emergy input ranged from 13.65% vs 86.35% in Xinjiang to 33.70% vs 66.30% in Heilongjiang, which were close to 30% vs 70%, 25% vs75%, 22% vs 78%, 20% vs 80% and 15% vs 85% for Northeast of China, Southwest of China, Loess Plateau, Huang-Huai-Hai Plain and Northwest of China respectively. Our study demonstrates that the natural energy in the maize ecosystem influenced the quantity and proportion of purchased energy. Different combinations of natural and purchased emergy were coupled to maintain the same ecosystem under the different environmental conditions. Its recommendation is to consider changing the crop production systems or artificial energy inputs in different regions based on differences in natural factors in order to make more efficient use of resources, reduce the use of chemical fertilizers, and promote the sustainability of ecosystems.
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•Maize ecosystems is more competitive than other agro-ecosystems, but it also has a high environmental loading ratio.•Natural and purchased energy were coupled to maintain the same ecosystem under the different environmental conditions.•The proportion of natural and purchased emergy input ranged from 30% vs 70% to 15% vs 85% for NE, SW, LP, HP and NW of China respectively.
Riparian ecosystems are vital components of aridlands within the southwestern United States. Historically, surface flows influenced population dynamics of native riparian trees. Many southwestern ...streams has been altered by regulation, however, and will be further affected by greenhouse warming. Our analysis of stream gage data revealed that decreases in volume of annual discharge and mean peak discharge and a shift to earlier peak discharge will occur in the Southern Rockies region of Colorado, New Mexico, and Utah. These changes will likely decrease rates of reproduction and survival of cottonwood (Populus fremontii and Populus deltoides ssp. wislizenii), Goodding's willow (Salix gooddingii), and boxelder (Acer negundo), which rely on surface flows to stimulate germination and recharge groundwater aquifers. Streams in the Central Highlands of Arizona and New Mexico will likely see reductions in annual discharge volume, which could limit reproduction and survival of the above taxa and Arizona sycamore (Platanus wrightii). These effects may be exacerbated by demands of expanding urban areas and agricultural operations, but could also be ameliorated by increasing water use efficiency and environmental mitigation. These factors must be considered, along with climate projections, when planning for conservation of riparian trees and the animal communities they support.
•Large trees are a key component of riparian ecosystems in the southwestern United States.•Streamflow dynamics, which influence riparian tree populations, vary among southwestern streams.•Projected streamflow characteristics vary among streams as well.•Future dynamics of riparian forests will be influenced by geophysical setting, woody plant composition, and human activity.
Chronic repeated gavage dosing of high concentrations of ethyl acrylate (EA) causes forestomach tumors in rats and mice. For two decades, there has been general consensus that these tumors are unique ...to rodents because of: i) lack of carcinogenicity in other organs, ii) specificity to the forestomach (an organ unique to rodents which humans do not possess), iii) lack of carcinogenicity by other routes of exposure, and iv) obvious site of contact toxicity at carcinogenic doses. In 1986, EA was classified as possibly carcinogenic to humans by the International Agency for Research on Cancer (IARC). However, by applying a MOA analyses and human relevance framework assessment, the weight-of-evidence supports a cytotoxic MOA with the following key events: i) bolus delivery of EA to forestomach lumen and subsequent absorption, ii) cytotoxicity likely due to saturation of enzymatic detoxification, iii) chronic regenerative hyperplasia, and iv) spontaneous mutation due to increased cell replication and cell population. Clonal expansion of initiated cells thus results in late onset tumorigenesis. The key events in this ‘wound and healing’ MOA provide high confidence in the MOA as assessed by evolved Bradford-Hill Criteria. The weight-of-evidence supported by the proposed MOA, combined with a unique tissue that does not exist in humans, indicates that EA is highly unlikely to pose a human cancer hazard.
•Forestomach tumors in rodents were observed after chronic gavage high EA dosing.•These tumors are unique to rodents because humans do not possess a forestomach.•No tumors were induced in other tissues or by other exposure routes.•Mode of action (MOA) analysis supports a non-genotoxic, cytotoxic MOA.•HRF assessment indicates that EA is highly unlikely to pose a human cancer hazard.
The utility of rodent forestomach tumor data for hazard and risk assessment has been examined for decades because humans do not have a forestomach, and these tumors occur by varying modes of action ...(MOAs). We have used the MOA for ethyl acrylate (EA) to develop an Adverse Outcome Pathway (AOP) for forestomach tumors caused by non-genotoxic initiating events. These tumors occur secondary to site of contact induced epithelial cytotoxicity and regenerative repair-driven proliferation. For EA, the critical initiating event (IE) is epithelial cytotoxicity, and supporting key events (KEs) at the cellular and tissue level are increased cell proliferation (KE1) resulting in sustained hyperplasia (KE2), with the adverse outcome of forestomach papillomas and carcinomas. For EA, a pre-molecular initiating event (pre-MIE) of sustained glutathione depletion is probable. Supporting data from butylated hydroxyanisole (BHA) are also reviewed. Although there may be some variability in the pre-MIEs and IEs for BHA and EA, they share the same KEs, and evidence for BHA confers support for the AOP. Evolved Bradford Hill considerations of biological plausibility, essentiality, and empirical support were evaluated per OECD guidance. Although an MIE is not specifically described, overall confidence in the AOP is high due to well-developed and accepted evidence streams, and the AOP can be used for regulatory applications including hazard identification and risk assessment for chemicals that act by this AOP.
•An Adverse Outcome Pathway (AOP) for forestomach tumors is described.•Data from ethyl acrylate (EA) mode of action and butylated hydroxyanisole studies.•For EA, a pre-molecular initiating event is sustained glutathione depletion.•The critical initiating event is sustained site of contact epithelial cytotoxicity.•Supporting key events are increased cell proliferation and sustained hyperplasia.
Our ability to link the breeding locations of individual passerines to migration stopover sites and wintering locations is limited. Stable isotopes of hydrogen contained in bird feathers have ...recently shown potential in this regard. We measured hydrogen stable-isotope ratios (δD) of feathers from breeding, migrating, and wintering Wilson's Warblers. Analyses of feathers from museum specimens collected throughout the western portion of the breeding range indicate that δD values are significantly negatively related to latitude of collection (R2=0.52), which is an indication that δD values are a good descriptor of breeding latitude. Analyses of feathers collected from birds migrating through the Bosque del Apache National Wildlife Refuge, New Mexico (USA), revealed a significantly positive relationship between δD values and the timing of autumn migration (R2=0.34), but not the timing of spring migration. This pattern indicates that Wilson's Warblers that bred furthest north migrated earliest in the autumn. Finally, analysis of feathers collected on the wintering grounds indicate that the hydrogen isotope ratio is significantly positively related to wintering latitude (R2=0.80), which indicates that birds that bred furthest north wintered furthest south. In combination, these patterns suggest that in the western portion of their range, Wilson's Warblers have a leapfrog migration system in which the northern-most breeding birds pass through New Mexico early in the autumn to arrive on the wintering grounds in southern Central America, the southern edge of the Wilson's Warblers winter range. We know of no other literature documenting or suggesting that Wilson's Warbler engage in leapfrog migration. We think the novelty of these results is a reflection of the potential for stable-isotope techniques to revise our understanding of bird migration.
Mechanical and fire treatments are commonly used to reduce fuels where land use practices have encouraged accumulation of woody debris and high densities of trees. Treatments focus on restoration of ...vegetation structure, but will also affect wildlife populations. Small mammal populations were monitored before and after dense tree stands were thinned on 2,800 ha in NM, U.S.A. Mammals were live‐trapped in upland and riparian habitats from 2002 to 2006 in thinned and unthinned forests. Populations of deer mice (Peromyscus maniculatus) and voles (Microtus spp.) were estimated using mark-recapture data. An index of abundance was used for chipmunks (Tamias spp.) and woodrats (Neotoma spp.). Deer mice responded positively to thinning in 2005 in upland and riparian habitats. Voles responded positively to thinning in 2005 and 2006 in riparian habitats. There was no change related to thinning in relative abundance of chipmunks and woodrats or in total small mammal biomass. Because abiotic processes affect wildlife populations, we also examined response of deer mouse populations to precipitation. After removing treatment effects, populations were modeled with winter and summer precipitation. In both upland and riparian habitats, deer mouse populations had a curvilinear response to precipitation from the preceding winter, while responding negatively to summer rainfall only in riparian habitats. Increases in deer mice populations occurred on thinned sites during a year of high winter precipitation, generally associated with depressed populations, indicating that forest thinning moderated this relationship. Results suggest that precipitation plays a role in determining timing and presence of response to restoration treatments.
Despite widespread efforts to avert wildfire by reducing the density of flammable vegetation, little is known about the effects of this practice on the reproductive biology of forest birds. We ...examined nest-site selection and nest survival of the Black-chinned Hummingbird (Archilochus alexandri) in New Mexico riparian forests treated or not for fuel reduction. In untreated plots the hummingbirds frequently nested in exotic trees such as saltcedar (Tamarix spp.) and Russian olive (Eleagnus angustifolia). Following fuel reduction, they increased use of cottonwood (Populus deltoides ssp. wislizenii) as a nest substrate and nested at greater heights. Though fuel reduction influenced habitat and nest-site selection, it did not immediately affect nest survival. A logistic exposure model containing effects of year and interaction of nest height and substrate explained nest survival better than did other models. Estimates of daily nest-survival rates from this model varied by year from 0.970 (95% CI: 0.949– 0.982) to 0.992 (95% CI: 0.983–0.996), corresponding with period survival rates of 31% (95% CI: 13.7%–50.1%) to 73% (95% CI: 52.1%–85.9%). In addition, in all substrates except saltcedar, nest survival decreased with nest height. Our relatively high nest-survival estimates suggest that the riparian forest along the Middle Rio Grande provides high-quality nesting habitat for this species. Fuel reduction, however, reduces nest-site availability and can lower nest survival by removing potential nest sites in the forest understory, forcing hummingbirds to nest at greater heights where predation risk is higher.
We compared plants used as sites for nests and survival of nests of black-chinned hummingbirds (Archilochus alexandri) along two rivers in New Mexico. Along the free-flowing Gila River which was ...dominated by native plants, most nests were constructed in boxelder (Acer negundo). Along the flow-restricted Middle Rio Grande which was dominated by nonnative plants, most nests were constructed in nonnative plants such as Russian olive (Elaeagnus angustifolia) and saltcedar (Tamarix). Mean nest height varied among species of plants used as nesting sites but was about 4 m at each study area. Logistic exposure-estimates of survival of nests were considerably higher along the Middle Rio Grande (52%) than the along the Gila River (23%). Survival of nests was influenced by nest height and species of plant used as nesting site, with survival rates of nests greatest at mean heights in Russian olive and saltcedar. Our results highlight considerable variation in nesting characteristics between two study areas and show that subcanopy nest-sites are essential components of productive habitat for this species.
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