Results 1 - 10 of 1325
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[en] Roanoke bass (Ambloplites cavifrons) persist in five river basins in the eastern US, where they are threatened by invasive species, habitat loss and degradation, and hydrologic fragmentation. We conducted the first conservation genetic study of A. cavifrons, analyzing variation at 19 nuclear microsatellite DNA loci and the cytochrome b mitochondrial DNA gene to estimate population structure and demography, genetic relationships among populations, and the role of landscape features in regulating genetic diversity and differentiation. Most streams harbored genetically distinguishable populations, with high connectivity among reaches within streams but no contemporary dispersal among streams. In contrast, mitochondrial divergence within and among basins was weak, suggesting historically higher range-wide connectivity. Most populations exhibited small effective population sizes and evidence of past population bottlenecks. Genetic diversity correlated positively with patch size but negatively with watershed urban and agricultural development, suggesting that habitat loss, degradation, and fragmentation have acted in concert to reduce population viability. Mitigating these impacts may require a combination of tactics, including restoring habitat, limiting the spread of invasive competitors, and reestablishing historical connectivity. (author)
[en] The giant panda Ailuropoda melanoleuca is one of the most iconic mammals in the world. The species has experienced declines in its habitat and population due to human disturbance. To protect this species, we investigated the relationship between giant panda habitat use intensity and human disturbance density in the Daxiangling Mountains. The results indicated that, among multiple kinds of disturbances, roads affected the giant panda habitat use significantly. In addition, roads caused the giant panda habitat use intensity to decline sharply. The giant panda nearly stopped using the habitat when road density was more than 0.4 km/km2. Thus, road density should be considered in the protection program. Furthermore, in areas inhabited by giant pandas, we recommend to optimizing and enhancing increased regulations to minimize the expansion and impact of roads. (author)
[en] This paper describes the development and implementation of two ecological restoration projects at the Fernald Preserve that are funded through a CERCLA natural resource damage settlement. The Paddys Run Tributary Project involves creation of vernal pool wetland habitat with adjacent forest restoration. The Triangle Area Project is a mesic tall-grass prairie establishment, similar to other efforts at the Fernald Preserve. The goal of the Fernald Natural Resource Trustees is to establish habitat for Ambystomatid salamander species, as well as grassland birds. Planning and implementation of on-property ecological restoration projects is one component of compensation for natural resource injury. As with the rest of the Fernald Preserve, ecological restoration has helped turn a DOE liability into a community asset. (authors)
[en] A river channel survey was completed along three reaches (totalling 14.3km), i.e. an unregulated stretch and two regulated reaches (with reduced flows) of the Soca River to assess the spatial pattern of CGU type, size, hydraulics and distribution. In addition, one regulated reach was re-surveyed at different discharges to investigate the dynamics of CGUs and their relationship with flow. CGUs were classified and mapped using visual assessment and physical measurements of the hydraulic characteristics (velocity and depth) in each CGU. The effect of flow regulation on the hydraulic character of the river becomes apparent by highlighting differences in the types of CGUs present between the regulated and unregulated reaches. Reduced flows from river regulation also significantly reduces the size of CGUs, alters their hydraulic character, and affects the longitudinal distribution of types by creating greater habitat fragmentation. Hydraulic preferences for spawning habitat of marble trout (Salmo marmoratus) were obtained from previous research. The hydraulic character of CGUs were analysed at different discharges and combined with the hydraulic preferences of the species to evaluate the impact of flow regulation on habitat availability. Analysis shows that intermediate measured flow provides increased spawning habitat availability in the chosen reach for this target species.
[en] Data on the N and C isotopic composition are presented for the Lower Triassic claystones of the Abrek section of southern Primorye (Far East). The results showed five N isotopic intervals and several negative C isotopic excursions of the Induan–lower Olenekian stages of the Abrek section.
[en] Bioinspired design approaches seek to exploit nature in order to construct optimal solutions for engineering problems as uniform temperature control in multizone systems. The ideal free distribution (IFD) is a concept from behavioural ecology, which describes the arrangement of individuals in different habitats such that at equilibrium, all habitats are equally suitable. Here, we relax the IFD's main assumptions using the standing-crop idea to introduce dynamics into the supplies of each habitat. Then, we make an analogy with a multizone thermal system to propose a controller based on the replicator dynamics model, in order to obtain a maximum uniform temperature subject to constant power injection. Besides, we analytically show that the equilibrium point of the controlled system is asymptotically stable. Finally, some practical results obtained with a testbed and comparisons with the theoretical results are presented.
[en] Systems that allow users to store and retrieve spatial data, provide for analyses of spatial data, and offer highly detailed display of spatial data are referred to as geographic information systems, or more typically, GIS. Since their initial usage in the 1960s, GISs have evolved as a means of assembling and analyzing diverse data pertaining to specific geographical areas, with spatial locations of the data serving as the organizational basis for the information systems. The structure of GISs is built around spatial identifiers and the methods used to encode data for storage and manipulation. This paper examines how GIS has been used in typical environmental assessment, its use for cumulative impact assessment, and explores litigation that occurred in the United States Federal court system where GIS was used in some aspect of cumulative effects. The paper also summarizes fifteen case studies that range from area wide transportation planning to wildlife and habitat impacts, and draws together a few lessons learned from this review of literature and litigation.
[en] Weeds are considered a limiting factor of crop production. Simultaneously, these non-crop plants are a portion of the agricultural ecosystem and play an essential role as viable habitat for many organisms, including bio-control agents. Utilizing the quadrate method, sugarcane, fodder, wheat and mustard croplands were sampled for one year to determine the weed flora and arthropods living among it. Twenty weed species and eight major arthropod orders were found to be present. The majority of the weed plants were broad-leaved, while some were grass-like. A review of literature on Central Punjab weeds uncovered depicted a considerable change in the weed flora over few decades. This could be related to the intensive and extensive farming in the area, which has this increased over the few decades along with the construction of an extensive irrigation canal system. These alterations may have caused drastic changes in the soil structure and climate of the region. Most of the phytophagous arthropod species used weed plants as food. In turn, these were fed upon by a few zoophagous arthropod species that also utilized the weeds for shelter and oviposition. Thus, weeds have a specific role within the agro-ecosystem by supporting local biodiversity. (author)
[en] Both environmental indicators and multi-metric indices are useful for describing baseline conditions and qualitatively predicting the cumulative consequences of multiple actions. Several examples and case studies associated with indicators and/or indices are presented herein. They can be easily modified for usage in CEAM. Habitat suitability models reflect special indices related to habitat needs and quality for specific species or broad habitat types. Such models have been used to address direct and indirect effects, and with some modification, they can be also used to address cumulative effects of multiple actions. This review has indicated that there are numerous examples of such tools which have been or could be used in both EIA and CEAM. Some key lessons are: (1) in conducting CEAM studies, it is useful to think from the mindset that 'I am the VEC or indicator, and what is my historical and current condition and how have I, or will I, be affected by multiple past, present, and future actions?'; (2) due to the likely absence of detailed information on future actions, the described tools can still be used to 'predict' future conditions by focusing on qualitative up-or-down changes in individual indicators or indices with their aggregated displays; and (3) numerous regional and site-specific tools are currently available, with one example being indices of biological integrity for specific watersheds and water bodies. Such tools, even though they may not have been developed for CEAM usage, can certainly benefit CEAM studies and practice. Finally, usage of selected and appropriate tools as described herein can aid in conducting science-based, systematic, and documentable CEAM studies.