Political transition and emergent forest‐conservation issues in Myanmar

Political and economic transitions have had substantial impacts on forest conservation. Where transitions are underway or anticipated, historical precedent and methods for systematically assessing future trends should be used to anticipate likely threats to forest conservation and design appropriate and prescient policy measures to counteract them. Myanmar is transitioning from an authoritarian, centralized state with a highly regulated economy to a more decentralized and economically liberal democracy and is working to end a long‐running civil war. With these transitions in mind, we used a horizon‐scanning approach to assess the 40 emerging issues most affecting Myanmar's forests, including internal conflict, land‐tenure insecurity, large‐scale agricultural development, demise of state timber enterprises, shortfalls in government revenue and capacity, and opening of new deforestation frontiers with new roads, mines, and hydroelectric dams. Averting these threats will require, for example, overhauling governance models, building capacity, improving infrastructure‐ and energy‐project planning, and reforming land‐tenure and environmental‐protection laws. Although challenges to conservation in Myanmar are daunting, the political transition offers an opportunity for conservationists and researchers to help shape a future that enhances Myanmar's social, economic, and environmental potential while learning and applying lessons from other countries. Our approach and results are relevant to other countries undergoing similar transitions.     

Modeling Effectiveness of Gradual Increases in Source Level to Mitigate Effects of Sonar on Marine Mammals

Ramp‐up or soft‐start procedures (i.e., gradual increase in the source level) are used to mitigate the effect of sonar sound on marine mammals, although no one to date has tested whether ramp‐up procedures are effective at reducing the effect of sound on marine mammals. We investigated the effectiveness of ramp‐up procedures in reducing the area within which changes in hearing thresholds can occur. We modeled the level of sound killer whales (Orcinus orca) were exposed to from a generic sonar operation preceded by different ramp‐up schemes. In our model, ramp‐up procedures reduced the risk of killer whales receiving sounds of sufficient intensity to affect their hearing. The effectiveness of the ramp‐up procedure depended strongly on the assumed response threshold and differed with ramp‐up duration, although extending the duration of the ramp up beyond 5 min did not add much to its predicted mitigating effect. The main factors that limited effectiveness of ramp up in a typical antisubmarine warfare scenario were high source level, rapid moving sonar source, and long silences between consecutive sonar transmissions. Our exposure modeling approach can be used to evaluate and optimize mitigation procedures. Modelado de la Efectividad de los Incrementos Graduales en el Nivel de la Fuente para Mitigar Efectos de Sonar sobre Mamíferos Marinos     

Degradation of isofenphos in cornfields with conservation tillage practices 1

Abstract

Isofenphos (Amaze®, Oftanol®, 1‐methylethyl 2‐[[ethoxy‐[(l‐methylethyl)aminol phosphinothloyl]oxy]benzoate) was applied at planting to study the effects of four different tillage treatments (no‐tillage, fall chisel plow, Paraplow®, and fall moldboard plow) on isofenphos degradation rates and routes in cornfields over two growing seasons. Soil samples were taken at intervals extending over 69 days each growing season. Tillage treatment had no significant effect on isofenphos degradation rates and products. However, the repeated application of isofenphos had a very significant effect on lsofenphos degradation. Degradation was much more rapid the second year. A laboratory experiment comparing sterile and nonsterlle soils, with and without isofenphos history, confirmed enhanced mlcrobial degradation resulting from two consecutive years of isofenphos application. In the first year, isofenphos oxon was found at greater amounts relative to the second year. Soil bioassays conducted on soils collected from the field at different dates in the second year showed that effective control of larvae was no longer present 21 days after isofenphos application in the field.     

Toxicity and biochemical impact of certain oxime carbamate pesticides against terrestrial snail,Theba pisana (Müller)

Abstract

The bran toxic baits (0.5 % w/w) of five oxime carbamate pesticides; aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were tested for their molluscicidal activity against Theba pisana snails under Laboratory conditions. In addition, the in vivo effects of these compounds on seven vital enzymes namely Acetylcholin‐esterase (AchE), glutathion‐S‐transferase (GST), glutamic oxlaoacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), acid phosphatase (AcP), alkaline phosphatase (AIP), and adenosine triphosphatase (ATPase) activities of the snail tissue were also investigated after 1,3, and 5 days of exposure. The results showed that methomyl was the most potent candidate, whereas thiofanox was the least effective one against the snails. LT₅₀’s values of aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were 5.77, 4.69, 2.31, 3.97 and 6.67 days, respectively. Results of the potency of the tested pesticides against AchE activity were in harmony with the toxicity of these compounds to snails. AchE, AcP, and AIP activities were inhibited by the tested pesticides. GST activity was inhibited by aldicarb but stimulated by oxamyl and thiofanox. Methomyl and oxamyl lead to significant elevation of GOT and GPT, whereas thiofanox treated snail induced a reduction of both enzymes activities. Aldicarb and aldoxycarb caused significant induction of ATPase activity.     

Functional nonredundancy of elephants in a disturbed tropical forest

Conservation efforts are often motivated by the threat of global extinction. Yet if conservationists had more information suggesting that extirpation of individual species could lead to undesirable ecological effects, they might more frequently attempt to protect or restore such species across their ranges even if they were not globally endangered. Scientists have seldom measured or quantitatively predicted the functional consequences of species loss, even for large, extinction‐prone species that theory suggests should be functionally unique. We measured the contribution of Asian elephants (Elephas maximus) to the dispersal of 3 large‐fruited species in a disturbed tropical moist forest and predicted the extent to which alternative dispersers could compensate for elephants in their absence. We created an empirical probability model with data on frugivory and seed dispersal from Buxa Tiger Reserve, India. These data were used to estimate the proportion of seeds consumed by elephants and other frugivores that survive handling and density‐dependent processes (Janzen‐Connell effects and conspecific intradung competition) and germinate. Without compensation, the number of seeds dispersed and surviving density‐dependent effects decreased 26% (Artocarpus chaplasha), 42% (Careya arborea), and 72% (Dillenia indica) when elephants were absent from the ecosystem. Compensatory fruit removal by other animals substantially ameliorated these losses. For instance, reductions in successful dispersal of D. indica were as low as 23% when gaur (Bos gaurus) persisted, but median dispersal distance still declined from 30% (C. arborea) to 90% (A. chaplasha) without elephants. Our results support the theory that the largest animal species in an ecosystem have nonredundant ecological functionality and that their extirpation is likely to lead to the deterioration of ecosystem processes such as seed dispersal. This effect is likely accentuated by the overall defaunation of many tropical systems.     

Improving credibility and transparency of conservation impact evaluations through the partial identification approach

The fundamental challenge of evaluating the impact of conservation interventions is that researchers must estimate the difference between the outcome after an intervention occurred and what the outcome would have been without it (counterfactual). Because the counterfactual is unobservable, researchers must make an untestable assumption that some units (e.g., organisms or sites) that were not exposed to the intervention can be used as a surrogate for the counterfactual (control). The conventional approach is to make a point estimate (i.e., single number along with a confidence interval) of impact, using, for example, regression. Point estimates provide powerful conclusions, but in nonexperimental contexts they depend on strong assumptions about the counterfactual that often lack transparency and credibility. An alternative approach, called partial identification (PI), is to first estimate what the counterfactual bounds would be if the weakest possible assumptions were made. Then, one narrows the bounds by using stronger but credible assumptions based on an understanding of why units were selected for the intervention and how they might respond to it. We applied this approach and compared it with conventional approaches by estimating the impact of a conservation program that removed invasive trees in part of the Cape Floristic Region. Even when we used our largest PI impact estimate, the program's control costs were 1.4 times higher than previously estimated. PI holds promise for applications in conservation science because it encourages researchers to better understand and account for treatment selection biases; can offer insights into the plausibility of conventional point‐estimate approaches; could reduce the problem of advocacy in science; might be easier for stakeholders to agree on a bounded estimate than a point estimate where impacts are contentious; and requires only basic arithmetic skills.     

Effects of Invasive Cordgrass on Presence of Marsh Grassbird in an Area where It Is Not Native

The threatened Marsh Grassbird (Locustella pryeri) first appeared in the salt marsh in east China after the salt marsh was invaded by cordgrass (Spartina alterniflora), a non‐native invasive species. To understand the dependence of non‐native Marsh Grassbird on the non‐native cordgrass, we quantified habitat use, food source, and reproductive success of the Marsh Grassbird at the Chongming Dongtan (CMDT) salt marsh. In the breeding season, we used point counts and radio‐tracking to determine habitat use by Marsh Grassbirds. We analyzed basal food sources of the Marsh Grassbirds by comparing the δ¹³C isotope signatures of feather and fecal samples of birds with those of local plants. We monitored the nests through the breeding season and determined the breeding success of the Marsh Grassbirds at CMDT. Density of Marsh Grassbirds was higher where cordgrass occurred than in areas of native reed (Phragmites australis) monoculture. The breeding territory of the Marsh Grassbird was composed mainly of cordgrass stands, and nests were built exclusively against cordgrass stems. Cordgrass was the major primary producer at the base of the Marsh Grassbird food chain. Breeding success of the Marsh Grassbird at CMDT was similar to breeding success within its native range. Our results suggest non‐native cordgrass provides essential habitat and food for breeding Marsh Grassbirds at CMDT and that the increase in Marsh Grassbird abundance may reflect the rapid spread of cordgrass in the coastal regions of east China. Our study provides an example of how a primary invader (i.e., cordgrass) can alter an ecosystem and thus facilitate colonization by a second non‐native species. Efectos de Spartina alterniflora Invasora Sobre Locustella pryeri en un Área Donde No Es Nativa