Cyhalofop‐p‐butyl mobility and distribution of residues in soil at various depths

This study was conducted to evaluate cyhalofop‐p‐butyl mobility in a sandy loam soil and subsequent distribution of residues at various depths under field conditions. Soil samples were taken from 0 to 150 cm depths at 3–90 d after rains in lysemeter of 1 and 2 m depths. Cyhalofop‐p‐butyl application at two rates and subsequent precipitation had a significant impact on soil, physico‐chemical properties and herbicide mobility. Precipitation caused substantial mobility of cyhalofop‐p‐butyl in the soil and 1.1–7.6 μg L^?1 of cyhalofop‐p‐butyl was found in leachates. Cyhalofop‐p‐butyl residues in the leachates were probably due to preferential flow through the soil. Cyhalofop‐p‐butyl residues were detected in significant amounts from the soil up to 10 d, later, residues were found below the detection limit but its three transformation products viz., cyhalofop acid, diacid, and phenol were detected.     

Projected Climate‐Induced Habitat Loss for Salmonids in the John Day River Network,Oregon, U.S.A.

Abstract: Climate change will likely have profound effects on cold‐water species of freshwater fishes. As temperatures rise, cold‐water fish distributions may shift and contract in response. Predicting the effects of projected stream warming in stream networks is complicated by the generally poor correlation between water temperature and air temperature. Spatial dependencies in stream networks are complex because the geography of stream processes is governed by dimensions of flow direction and network structure. Therefore, forecasting climate‐driven range shifts of stream biota has lagged behind similar terrestrial modeling efforts. We predicted climate‐induced changes in summer thermal habitat for 3 cold‐water fish species—juvenile Chinook salmon, rainbow trout, and bull trout (Oncorhynchus tshawytscha, O. mykiss, and Salvelinus confluentus, respectively)—in the John Day River basin, northwestern United States. We used a spatially explicit statistical model designed to predict water temperature in stream networks on the basis of flow and spatial connectivity. The spatial distribution of stream temperature extremes during summers from 1993 through 2009 was largely governed by solar radiation and interannual extremes of air temperature. For a moderate climate change scenario, estimated declines by 2100 in the volume of habitat for Chinook salmon, rainbow trout, and bull trout were 69–95%, 51–87%, and 86–100%, respectively. Although some restoration strategies may be able to offset these projected effects, such forecasts point to how and where restoration and management efforts might focus.     

Shift of Spawning Season and Effects of Climate Warming on Developmental Stages of a Grayling (Salmonidae)

Abstract: River‐dwelling fish, such as European graylings (Thymallus thymallus), are susceptible to changes in climate because they can often not avoid suboptimal temperatures, especially during early developmental stages. We analyzed data collected in a 62‐year‐long (1948–2009) population monitoring program. Male and female graylings were sampled about three times/week during the yearly spawning season in order to follow the development of the population. The occurrence of females bearing ripe eggs was used to approximate the timing of each spawning season. In the last years of the study, spawning season was more than 3 weeks earlier than in the first years. This shift was linked to increasing water temperatures as recorded over the last 39 years with a temperature logger at the spawning site. In early spring water temperatures rose more slowly than in later spring. Thus, embryos and larvae were exposed to increasingly colder water at a stage that is critical for sex determination and pathogen resistance in other salmonids. In summer, however, fry were exposed to increasingly warmer temperatures. The changes in water temperatures that we found embryos, larvae, and fry were exposed to could be contributing to the decline in abundance that has occurred over the last 30–40 years.     

Ex situ management as insurance against extinction of mammalian megafauna in an uncertain world

The persistence of endangered species may depend on the fate of a very small number of individual animals. In situ conservation alone may sometimes be insufficient. In these instances, the International Union for Conservation of Nature provides guidelines for ex situ conservation and the Convention on Biological Diversity (CBD) indicates how ex situ management can support the CBD's objectives by providing insurance policies for species. The circumstances that justify its use are uncertain. To evaluate the current in situ extinction risk and ex situ management of 43 critically endangered species of mammalian megafauna, we used nonmetric multidimensional scaling and geopolitical variables related to governance, economics, and national policy within their extant ranges. We then fitted generalized additive models to assess the contribution of each variable to the ordination. Fifteen (almost one-third) of the world's terrestrial mammalian megafauna are not the subject of any ex situ management. Seventy-three percent of these taxa occur in areas characterized by political uncertainty, such as border zones or areas affected by armed conflicts, mainly in Africa and the Middle East. A further 23% of taxa in ex situ programs do not meet sustainability criteria for inbreeding avoidance. Strategic conservation planning, such as the One Plan approach, may improve ex situ management for these taxa. Given the escalating trend in threats afflicting megafauna, ex situ management should be considered more rigorously, particularly in politically unstable regions, to achieve CBD Target 12 (prevent extinction of threatened species).     

Potential Reflection of Distinct Ecological Units in Plant Endemism Categories

Abstract: The level of endemism at a site may indicate species richness of the site. Nevertheless, assessing endemism levels in taxonomic groups such as plants may be difficult because the species richness of plants is high relative to species richness of other taxonomic groups (e.g., vertebrates). A major problem in determining whether plant species are endemic is the lack of standardization of the geographic extent of endemism: species are considered endemic to, for example, countries, continents, or states. We compiled a history of the concept of endemism as it applies to plants. The application of the concept to geographic distribution dates from the 19th century, when European explorers discovered many taxa exclusive to regions outside Europe. Two types of endemism, paleoendemism and neoendemism, were then acknowledged, according to evolutionary age, and these categories are still in use. In the 20th century, most of the research on endemism focused on explaining range restriction on the basis of cytological data, edaphic and geological factors, and phylogeny. This research led to a vast number of concepts, of which only edaphic endemism remains relatively well accepted. More recently, researchers suggest that competition may determine endemism in some cases. We suggest that plants be labeled as endemic only if their distribution occurs in a distinct ecological unit, such as a biome. On the basis of a literature review of the factors that cause range restriction, we categorized endemic taxa as paleoendemic, neoendemic, edaphically endemic, or suppressed endemic. For example, Schlechtendalia luzulifolia, is a rare forb that is a paleoendemic species of the granite and sandstone‐based grasslands of the Pampa. Levels of endemism in southern Brazilian grasslands are poorly known. We emphasize the importance of recognizing these grasslands as a single transnational biome so that levels of endemism of species therein can be assessed correctly.     

Photooxidative removal of the herbicide Acid Blue 9 in the presence of hydrogen peroxide: modeling of the reaction for evaluation of electrical energy per order (EEO)

The present work deals with photooxidative removal of the herbicide, Acid Blue 9 (AB9), in water in the presence of hydrogen peroxide (H₂O₂) under UV light illumination (30 W). The influence of the basic operational parameters such as amount of H₂O₂, irradiation time and initial concentration of AB9 on the photodegradation efficiency of the herbicide was investigated. The degradation rate of AB9 was not appreciably high when the photolysis was carried out in the absence of H₂O₂ and it was negligible in the absence of UV light. The photooxidative removal of the herbicide was found to follow pseudo-first-order kinetic, and hence the figure-of-merit electrical energy per order (E_Eo) was considered appropriate for estimating the electrical energy efficiency. A mathematical relation between the apparent reaction rate constant and H₂O₂ used was applied for prediction of the electricity consumption in the photooxidative removal of AB9. The results indicated that this kinetic model, based on the initial rates of degradation, provided good prediction of the E_Eo values for a variety of conditions. The results also indicated that the UV/H₂O₂ process was appropriate as the effective treatment method for removal of AB9 from the contaminated wastewater.     

Epiphyte Biodiversity in the Coffee Agricultural Matrix: Canopy Stratification and Distance from Forest Fragments

Abstract: Quality of the agricultural matrix profoundly affects biodiversity and dispersal in agricultural areas. Vegetatively complex coffee agroecosystems maintain species richness at larger distances from the forest. Epiphytes colonize canopy trees and provide resources for birds and insects and thus effects of agricultural production on epiphytes may affect other species. We compared diversity, composition, and vertical stratification of epiphytes in a forest fragment and in two coffee farms differing in management intensity in southern Mexico. We also examined spatial distribution of epiphytes with respect to the forest fragment to examine quality of the two agricultural matrix types for epiphyte conservation. We sampled vascular epiphytes in a forest fragment, a shade polyculture farm, and a shade monoculture farm at 100 m, 200 m, and 400 m from the forest. Epiphyte and orchid richness was greater in the forest than in the monoculture but richness was similar in the forest and polyculture farm. Epiphyte species composition differed with habitat type, but not with distance from the forest. In the forest, epiphytes were distributed throughout tree canopies, but in the farms, epiphytes were primarily found on trunks and larger branches. Epiphyte richness and species similarity to forest species declined with distance from the forest fragment in the monoculture, but richness and similarity to forest species did not decline with distance from forest in the polyculture. This suggests polyculture coffee has greater conservation value. In contrast, monoculture coffee is likely a sink habitat for epiphytes dispersing from forests into coffee. Coffee farms differ from forests in terms of the habitat they provide and species composition, thus protecting forest fragments is essential for epiphyte conservation. Nonetheless, in agricultural landscapes, vegetatively complex coffee farms may contribute to conservation of epiphytes more than other agricultural land uses.     

A Regional Perspective on the Diversity and Conservation of Tropical Andean Fishes

Abstract: The tropical Andes harbor an extraordinarily varied concentration of species in a landscape under increasing pressure from human activities. Conservation of the region's native plants and animals has received considerable international attention, but the focus has been on terrestrial biota. The conservation of freshwater fauna, particularly the conservation of fishes, has not been emphasized. Tropical Andean fishes are among the most understudied vertebrates in the world. We estimate that between 400 and 600 fish species inhabit the diverse aquatic environments in the region. Nearly 40% of these species are endemic. Tropical Andean fishes are vulnerable to ongoing environmental changes related to deforestation, water withdrawals, water pollution, species introductions, and hydropower development. Additionally, their distributions and population dynamics may be affected by hydrologic alterations and warmer water temperatures associated with projected climate change. Presently, at least three species are considered extinct, some populations are endangered, and some species are likely to decline or disappear. The long‐term persistence of tropical Andean fishes will depend on greater consideration of freshwater systems in regional conservation initiatives.     

Predicting the Probability of Outbreeding Depression

Abstract: Fragmentation of animal and plant populations typically leads to genetic erosion and increased probability of extirpation. Although these effects can usually be reversed by re‐establishing gene flow between population fragments, managers sometimes fail to do so due to fears of outbreeding depression (OD). Rapid development of OD is due primarily to adaptive differentiation from selection or fixation of chromosomal variants. Fixed chromosomal variants can be detected empirically. We used an extended form of the breeders’ equation to predict the probability of OD due to adaptive differentiation between recently isolated population fragments as a function of intensity of selection, genetic diversity, effective population sizes, and generations of isolation. Empirical data indicated that populations in similar environments had not developed OD even after thousands of generations of isolation. To predict the probability of OD, we developed a decision tree that was based on the four variables from the breeders’ equation, taxonomic status, and gene flow within the last 500 years. The predicted probability of OD in crosses between two populations is elevated when the populations have at least one of the following characteristics: are distinct species, have fixed chromosomal differences, exchanged no genes in the last 500 years, or inhabit different environments. Conversely, the predicted probability of OD in crosses between two populations of the same species is low for populations with the same karyotype, isolated for <500 years, and that occupy similar environments. In the former case, we recommend crossing be avoided or tried on a limited, experimental basis. In the latter case, crossing can be carried out with low probability of OD. We used crosses with known results to test the decision tree and found that it correctly identified cases where OD occurred. Current concerns about OD in recently fragmented populations are almost certainly excessive.