Inhibitory Effects on Esterase Enzymes Buche and Ache in Rainbow Trout (Oncorhyncus mykiss) Produced by the Slow Release Insecticide Chitosan Diethyl Phosphate

The study on the toxicity of chitosan diethyl phosphate (ChDP), a controlled release insecticide, on the activities of butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) in rainbow trout exposed to this pesticide was carried out. It was found that ChDP reduced BuChE activity in O. mykiss by a factor of eight at 6 days, with high fluctuation to the end of the exposition time at 12 days. The in vitro analysis of brain AChE treated with ChDP and Phenamiphos showed that it was competitively inhibited by both organophosphates. The values obtained for K_m and V_max for the AChE-ChDP (K_m: 21.23 μ M; V_max: 43.10 μ mol/min/g) and AChE-Phenamiphos (K_m: 38.62 μ M; V_max: 38.91 μ mol/min/g) systems were relatively low compared to values of the AChE (control) system (K_m: 62.99 μ M; V_max: 63.29 μ mol/min/g). Results reported in this study confirmed that chitosan diethyl phosphate performs similarly to organophosphate pesticides, producing inhibition in cholinesterases in rainbow trout.     

Effects of the Presence of Official‐Looking Volunteers on Harassment of New Zealand Fur Seals

Abstract: An increased number of tourists viewing animals in the wild have increased stress on these animals (hereafter wildlife). Many wildlife‐viewing locations rely on voluntary compliance with posted regulations to protect animals from tourists because of the expense of employing on‐site enforcement personnel. Voluntary compliance, however, is ineffective. The presence of official‐looking volunteers may decrease the incidence of wildlife harassment by tourists. To test this possibility, we observed tourists interacting with 5‐ to 12‐month‐old New Zealand fur seals (Arctocephalus forsteri) at the popular Ohau Stream waterfall while in the absence or presence of a young woman in plain sight wearing a neon vest (i.e., observer) and when an observer was not present. We observed 254 tourist groups at the waterfall when young seals were present. The percentage of groups in which at least one person harassed (approached, touched, or threw objects) a young seal was two‐thirds lower when the official‐looking observer was present. Frequency of harassment was inversely related to observer presence. Programs in which volunteers work at tourist sites are popular in countries with high tourism rates, such as New Zealand. Our results show that a relatively inexpensive and effective tourism‐management strategy may be to post such volunteers as observers at sites where tourists view wildlife.     

Ambient Ultraviolet B Radiation and Prevalence of Infection by Batrachochytrium dendrobatidis in Two Amphibian Species

Abstract: Chytridiomycosis, the emerging disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd) is responsible for declines and extirpations of amphibian populations worldwide. Environmental covariates modify the host‐Bd interaction and thus affect the ongoing spread of the pathogen. One such covariate may be the intensity of ultraviolet B (UV‐B) radiation. In a field experiment conducted in Laguna Grande de Peñalara (central Spain), a mountainous region where the presence of Bd has been documented since 1997, we analyzed the potential effect of environmental UV‐B (daily maximum 2.5–3.9 W/m²) on the susceptibility of larvae of the common toad (Bufo bufo) to Bd. The proportion of infected individuals increased as tadpoles developed. The prevalence of Bd was significantly lower in tadpoles exposed to environmental UV‐B intensities (2.94%) than in tadpoles not exposed to the radiation (9.72%). This finding mirrors that seen for a second amphibian species, the European midwife toad (Alytes obstetricans), for which conditional prevalence (i.e., prevalence of infection conditioned on the probability of a site being infected) across the Iberian Peninsula was inversely correlated with the intensity of UV‐B.     

Metabolism of DDT in Different Tissues of Young Rats

The bioconcentration and distribution pattern of p,p′-DDT 1,1,1-1trichloro-2,2-bis(2-chlorophenyl-4-chlorophenyl)-ethane] and its main metabolites (p,p′-DDD [1,1-dichloro-2,2-bis (4-chlorophenyl) ethane] and p,p′-DDE [1,1-dichloro-2,2-bis (4-chlorophenyl) in adipose tissue, liver, brain, kidney, thymus, and testis were examined in young rats after 10 days of intraperitoneal injection of 50 and 100 mg of p,p′-DDT/kg of body weight. Analyses were performed by high-resolution gas chromatography. p,p′-DDT was found to be accumulated in a dose-dependent manner with the highest concentration in adipose tissue. However, in brain, the accumulation of pesticide was low and remained unchanged at the higher dose. This difference may relate to the protective role of the blood-brain barrier, which limits the access of the xenobiotic in the cerebral compartment, and to the differential tissue lipid composition. Although tissues concentration of p,p′-DDE and p,p′-DDD correlated positively to total p,p′-DDT levels, the active role in detoxification of pollutants may explain why p,p′-DDD is more abundant in liver than in the rest of organs. On the contrary, in brain, the concentration of p,p′-DDE is higher than that of p,p′-DDD, suggesting that the metabolism of the parent insecticide proceeds via more than one pathway.     

Multiple Lineages of Avian Malaria Parasites (Plasmodium) in the Galapagos Islands and Evidence for Arrival via Migratory Birds

Haemosporidian parasites in the genus Plasmodium were recently detected through molecular screening in the Galapagos Penguin (Spheniscus mendiculus). We summarized results of an archipelago‐wide screen of 3726 endemic birds representing 22 species for Plasmodium spp. through a combination of molecular and microscopy techniques. Three additional Plasmodium lineages were present in Galapagos. Lineage A–infected penguins, Yellow Warblers (Setophaga petechia aureola), and one Medium Ground Finch (Geospiza fortis) was detected at multiple sites in multiple years. The other 3 lineages were each detected at one site and at one time; apparently, they were transient infections of parasites not established on the archipelago. No gametocytes were found in blood smears of infected individuals; thus, endemic Galapagos birds may be dead‐end hosts for these Plasmodium lineages. Determining when and how parasites and pathogens arrive in Galapagos is key to developing conservation strategies to prevent and mitigate the effects of introduced diseases. To assess the potential for Plasmodium parasites to arrive via migratory birds, we analyzed blood samples from 438 North American breeding Bobolinks (Dolichonyx oryzivorus), the only songbird that regularly migrates through Galapagos. Two of the ephemeral Plasmodium lineages (B and C) found in Galapagos birds matched parasite sequences from Bobolinks. Although this is not confirmation that Bobolinks are responsible for introducing these lineages, evidence points to higher potential arrival rates of avian pathogens than previously thought. Linajes Múltiples de Parásitos de Malaria Aviar (Plasmodium) en las Islas Galápagos y Evidencia de su Arribo por Medio de Aves Migratorias     

Use of Spatial Capture‐Recapture Modeling and DNA Data to Estimate Densities of Elusive Animals

Abstract: Assessment of abundance, survival, recruitment rates, and density (i.e., population assessment) is especially challenging for elusive species most in need of protection (e.g., rare carnivores). Individual identification methods, such as DNA sampling, provide ways of studying such species efficiently and noninvasively. Additionally, statistical methods that correct for undetected animals and account for locations where animals are captured are available to efficiently estimate density and other demographic parameters. We collected hair samples of European wildcat (Felis silvestris) from cheek‐rub lure sticks, extracted DNA from the samples, and identified each animals’ genotype. To estimate the density of wildcats, we used Bayesian inference in a spatial capture‐recapture model. We used WinBUGS to fit a model that accounted for differences in detection probability among individuals and seasons and between two lure arrays. We detected 21 individual wildcats (including possible hybrids) 47 times. Wildcat density was estimated at 0.29/km² (SE 0.06), and 95% of the activity of wildcats was estimated to occur within 1.83 km from their home‐range center. Lures located systematically were associated with a greater number of detections than lures placed in a cell on the basis of expert opinion. Detection probability of individual cats was greatest in late March. Our model is a generalized linear mixed model; hence, it can be easily extended, for instance, to incorporate trap‐ and individual‐level covariates. We believe that the combined use of noninvasive sampling techniques and spatial capture‐recapture models will improve population assessments, especially for rare and elusive animals.     

Advancing the Integration of History and Ecology for Conservation

Abstract: The important role of humans in the development of current ecosystems was recognized decades ago; however, the integration of history and ecology in order to inform conservation has been difficult. We identified four issues that hinder historical ecological research and considered possible solutions. First, differences in concepts and methods between the fields of ecology and history are thought to be large. However, most differences stem from miscommunication between ecologists and historians and are less substantial than is usually assumed. Cooperation can be achieved by focusing on the features ecology and history have in common and through understanding and acceptance of differing points of view. Second, historical ecological research is often hampered by differences in spatial and temporal scales between ecology and history. We argue that historical ecological research can only be conducted at extents for which sources in both disciplines have comparable resolutions. Researchers must begin by clearly defining the relevant scales for the given purpose. Third, periods for which quantitative historical sources are not easily accessible (before AD 1800) have been neglected in historical ecological research. Because data from periods before 1800 are as relevant to the current state of ecosystems as more recent data, we suggest that historical ecologists actively seek out data from before 1800 and apply analytic methods commonly used in ecology to these data. Fourth, humans are not usually considered an intrinsic ecological factor in current ecological research. In our view, human societies should be acknowledged as integral parts of ecosystems and societal processes should be recognized as driving forces of ecosystem change.