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141.
142.
143.
Newton M Cole EC Tinsley IJ 《Environmental science and pollution research international》2008,15(7):573-583
Background, aim, and scope Large-scale deforestation is occurring in subarctic North America following clearing by salvage logging or insect attack.
Numerous shrubs, herbs, and deciduous tree species tend to dominate areas on which stands of white spruce have grown. In the
absence of economically advantageous mechanical methods, several herbicides have value in efforts to reforest by planting
white spruce. Glyphosate, imazapyr, triclopyr, and hexazinone are all capable of selectively removing many competing species,
but there is concern about whether they would degrade naturally or persist owing to the frigid climate.
Materials and methods We established test plots with all four herbicides in upland and river bottom sites at 65°N and 58°N latitudes. The northern
site has extremely cold winters, with soils that freeze to a depth of 1–2 m, and precipitation of 275 mm/year. The southern
site has heavy rain and snowfall, amounting to 2,250 mm/year evenly distributed. Soil seldom freezes deeply. On each test
plot, one of the four herbicides was applied at twice the normal operational use rate to facilitate detection. They were applied
at the normal timing, with hexazinone, imazapyr, and triclopyr applied in June and glyphosate applied in fall. Soils were
sampled immediately after treatment and those samples used as references for dissipation data gathered over the next 11–14 months
from soil 0- to 15- and 15- to 45-cm depths.
Results Dissipation rates did not follow first-order rates because freezing conditions slowed most microbial activity. All products
dissipated to close to or below detection limits within the time of the study. Dissipation from vegetation was substantially
more rapid and depended on the nature of the plants treated as well as the product used. While soil residues dissipated more
slowly than in temperate regions, they did display consistent dissipation patterns during above-freezing conditions and also
the influence of microbial activity. Mobility was very limited with all products but hexazinone.
Discussion These products dissipate during summer in high latitudes much as they would in temperate climates. Winter changes are small,
but are not unlike some changes reported elsewhere under freezing conditions. Unlike many other studies, soil water did not
influence dissipation heavily, but the high latitude and semi-arid climate also did not create severely droughty soils. Residues
in plants were much higher than those in soils, but denatured the vegetation quickly, leading to unsuitability for forage
in any case.
Conclusions Low toxicity of these products and their metabolites combined with consistent dissipation and low mobility suggest that toxic
hazard of their use at high latitudes need not be a matter of serious concern to humans, terrestrial wildlife, or aquatic
systems. They are safe for use in management and rehabilitation of boreal forests when used properly.
Recommendations and perspectives Dissipation at rates approaching those in warmer climates offer a hypothesis that microflora native to high latitudes may
be adapted to destruction of such molecules at lower temperatures than may be indicated by experiments with microflora adapted
to warmer climates. Residues pose no observable risk to wildlife or humans in the area of use when products are applied properly.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available for authorized users. 相似文献
144.
Thomas Tanner Rizwan Uz Zaman Sunil Acharya Elizabeth Gogoi Aditya Bahadur 《Disasters》2019,43(Z3):S388-S411
One way to make development pathways more resilient in the face of a changing climate has been through mainstreaming adaptation into government policies, planning and sectoral decision‐making. To date, many of the transferable lessons have taken the form of technical approaches such as risk assessments and toolkits. This article instead draws on evidence from South Asia to emphasise some of the more tacit and informal approaches used to influence adaptation policy. Despite their apparent significance in policy processes, such tactics are often neither planned for nor well reported in resilience‐building projects and programme documents. Using evidence to populate a typology of influencing strategies, this article looks particularly at the role of policy entrepreneurs who navigate the political complexity of both formal and informal governance systems to promote successful adaptation mainstreaming. It concludes with recommendations for adaptation and resilience programming that can more effectively harness the breadth of influencing strategies. 相似文献
145.
David A. Wiedenfeld Allison C. Alberts Ariadne Angulo Elizabeth L. Bennett Onnie Byers Topiltzin Contreras-MacBeath Gláucia Drummond Gustavo A. B. da Fonseca Claude Gascon Ian Harrison Nicolas Heard Axel Hochkirch William Konstant Penny F. Langhammer Olivier Langrand Frederic Launay Daniel J. Lebbin Susan Lieberman Barney Long Zhi Lu Michael Maunder Russell A. Mittermeier Sanjay Molur Razan Khalifa al Mubarak Michael J. Parr Jonah Ratsimbazafy Anders G. J. Rhodin Anthony B. Rylands Jim Sanderson Wes Sechrest Pritpal Soorae Jatna Supriatna Amy Upgren Jean-Christophe Vié Li Zhang 《Conservation biology》2021,35(5):1388-1395
Some conservation prioritization methods are based on the assumption that conservation needs overwhelm current resources and not all species can be conserved; therefore, a conservation triage scheme (i.e., when the system is overwhelmed, species should be divided into three groups based on likelihood of survival, and efforts should be focused on those species in the group with the best survival prospects and reduced or denied to those in the group with no survival prospects and to those in the group not needing special efforts for their conservation) is necessary to guide resource allocation. We argue that this decision-making strategy is not appropriate because resources are not as limited as often assumed, and it is not evident that there are species that cannot be conserved. Small population size alone, for example, does not doom a species to extinction; plants, reptiles, birds, and mammals offer examples. Although resources dedicated to conserving all threatened species are insufficient at present, the world's economic resources are vast, and greater resources could be dedicated toward species conservation. The political framework for species conservation has improved, with initiatives such as the UN Sustainable Development Goals and other international agreements, funding mechanisms such as The Global Environment Facility, and the rise of many nongovernmental organizations with nimble, rapid-response small grants programs. For a prioritization system to allow no extinctions, zero extinctions must be an explicit goal of the system. Extinction is not inevitable, and should not be acceptable. A goal of no human-induced extinctions is imperative given the irreversibility of species loss. 相似文献
146.
This paper uses a cellular automata simulation model of a hypothetical landscape to investigate the role of location as it relates to the efficacy of land retirement in achieving two environmental goals: hydrological improvement and habitat improvement. Statistical analysis of simulation results is used to show how absolute and relative location relate to achievement of these objectives. Linear and nonlinear compromise programming frameworks then combine these two environmental objectives and a cost minimization objective into a measure that allows decision-makers to rank the desirability of different retirement strategies. These frameworks are explored to determine what each implies about the tradeoffs that must be made among objectives and among the spatial land parcel characteristics that contribute to those objectives. 相似文献
147.
Section 7(a)(2) of the Endangered Species Act directs federal agencies to ensure that their actions do not jeopardize the
continued existence of endangered and threatened species. The US Fish and Wildlife Service (USFWS) issues jeopardy or nonjeopardy
biological opinions on proposed federal actions that affect endangered and threatened species. We summarize several biological
opinions issued by the USFWS to protect the threatened piping plover (Charadrius melodus). These opinions address federal actions involving hundreds of piping plovers on the Missouri River system and a few piping
plover pairs on short stretches of Atlantic coast beach. Some of these opinions are decisive, but most allow the proposed
action to proceed conditional upon a lengthy set of reasonable and prudent alternatives to protect the piping plover. These
conditions may prove difficult to track and will add to the workload of the USFWS. 相似文献
148.
Social insect colonies respond to challenges set by a variable environment by reallocating work among colony members. In many social insects, such colony-level task allocation strategies are achieved through individual decisions that produce a self-organized adapting group. We investigated colony responses to parasitoids and native ant competitors in the red imported fire ant (Solenopsis invicta). Parasitoid flies affected fire ants by decreasing the proportion of workers engaged in foraging. Competitors also altered colony-level behaviours by reducing the proportion of foraging ants and by increasing the proportion of roaming majors, whose role is colony defence. Interestingly, the presence of both parasitism and competition almost always had similar effects on task allocation in comparison to each of the biotic factors on its own. Thus, our study uniquely demonstrates that the interactive effect of both parasitism and competition is not necessarily additive, implying that these biotic factors alter colony behaviour in distinct ways. More generally, our work demonstrates the importance of studying the dynamics of species interactions in a broader context. 相似文献
149.
Stephen J. Rossiter Gareth Jones Roger D. Ransome Elizabeth M. Barratt 《Behavioral ecology and sociobiology》2002,51(6):510-518
Female greater horseshoe bats (Rhinolophus ferrumequinum) exhibit strong natal philopatry to their maternity roost over many years, leading to the aggregation of matrilineal kin. Maternity colonies may, therefore, be expected to comprise highly related individuals, and, as such, provide conditions suitable for the evolution of kin-selected behaviours. To test these predictions, we examined relatedness and behaviour among matrilineal kin within a colony in south-west Britain. Genetic analysis of 15 matrilines, identified from microsatellite genotyping and long-term ringing surveys, revealed average relatedness levels of 0.17 to 0.64. In contrast, background relatedness among colony females approximated to zero (0.03). These results suggest that inclusive fitness benefits may only be accrued through discriminate cooperation within matrilines, and not at the wider colony level. To examine whether the potential for such benefits is realised through kin- biased cooperation during foraging, females from two matrilines were radio-tracked simultaneously over 3 years. Pairwise home-range overlap correlated significantly with Hamilton's relatedness coefficient. The greatest spatial associations were observed between females and their adult daughters, which shared both foraging grounds and night roosts, sometimes over several years. Tagged females, however, generally foraged and roosted alone, suggesting that kin-biased spatial association probably does not result from either information-transfer or cooperative territorial defence. Such patterns may instead result from a mechanism of maternal inheritance of preferred foraging and roosting sites. 相似文献
150.
Genetic structure and phylogeography of the lined shore crab, Pachygrapsus crassipes, along the northeastern and western Pacific coasts 总被引:1,自引:0,他引:1
Marine invertebrates with high larval dispersal capacity typically exhibit low degrees of population differentiation, which reflects both contemporary and historical processes. We sampled 346 individuals from seven populations of the lined shore crab, Pachygrapsus crassipes Randall, along the northeastern Pacific Coast and Korea during summer 2003. DNA sequence analysis of 613 bp of the mitochondrial COI gene showed that overall gene diversity (h) was high (0.92±0.01), whereas overall nucleotide diversity (π) was low (0.009±0.005). A total of 154 mtDNA haplotypes were identified; however, 114 were present in only one individual. Analysis of molecular variance revealed significant genetic structuring at Point Conception, CA, USA, that is likely due to the oceanographic circulation patterns, which result in asymmetrical migration of haplotypes. However, genetic variation among eastern Pacific populations was generally low, probably because of high contemporary gene flow and recent common ancestry of haplotypes. Mismatch analysis and nested clade analysis suggested that the population history of this region is characterized by two contiguous northwards range expansions, which are congruent with Late Pleistocene glacial cycles. Highly significant genetic differentiation was detected between eastern Pacific populations and Korea, indicating transpacific gene flow is restricted. Time of divergence between the two transpacific lineages was estimated between 0.8 and 1.2 Myrs ago. The small, recently founded population of P. crassipes at Bamfield, BC, Canada, did not appear to have undergone a founder effect. 相似文献