Chytridiomycosis Widespread in Anurans of Northeastern United States

ABSTRACT An emerging disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis has been associated with morbidity, mortality, and extinction of species. Typically, researchers have detected B. dendrobatidis only when examining amphibians for causes of mortalities; few data exist on infection rates where mortalities are lacking. During May-September 2000–2002 we obtained amphibian specimens killed by vehicles and others collected at remote off-road sites throughout Maine, USA, and from federal lands in 5 states in the Northeast. We detected infected specimens, mostly green frogs (Rana clamitans), at 5 of 7 national wildlife refuges, a federal waterfowl production area, and Acadia National Park. Seven of 9 species, including all Ranidae species, were infected throughout Maine; rates ranged from 14.6% in American toads (Bufo americanus) to 25.7% in northern leopard frogs (Rana pipiens). We did not detect any infections in 50 eastern gray tree frogs (Hyla versicolor) or 21 spring peepers (Pseudacris crucifer). Species that hibernate in terrestrial habitats seem to have lower rates of infection than species that hibernate in aquatic habitats. Infections peaked in spring and autumn and were associated with air temperatures optimal for B. dendrobatidis growth. The relatively high infection rates among species without documented die-offs suggest that either losses have occurred undetected, that the fungus is endemic and species have attained a level of resistance to infections becoming lethal, or that climatic conditions of the Northeast have a role in preventing infections from being lethal. Data on prevalence and distribution of this chytrid fungus in the Northeast may be useful in modeling its origins and predicting long-term ecosystem effects involving anurans.     

英格兰洞穴苔藓植物区系特征及其岩溶沉积研究

根据作者1998－2000年采自英格兰7个岩溶洞穴452份苔藓植物标本研究,英格兰岩溶洞穴苔藓植物区系具有下列特征：（1）区系种类由20科41属65种（含变种亚种）组成;（2）区系地理成分含北温带分布（52．30％）、温带欧洲分布（15．38％）、欧洲－亚洲分布（1．54％）、欧洲－北美分布（12．31％）、旧世界温带分布（4．62％）、英国特有（1．54％）和世界广泛分布（12．31％）等7种成分;（3）生活型含高丛集型（9．22％）、矮丛集型（20％）、交织型（61．54％）、扇型（4．08％）和平铺型（4．08％）5种类型。14种洞穴苔藓植物参与了洞穴洞口钙华沉积,沉积形态包括钟乳石、洞壁钙华、洞底泉华和洞底滴水钙华4种类型。     

Laboratory evaluation of desiccants and insecticidal soap applied to various substrates to control the deer tick Ixodes scapularis

Abstract. Desiccant and soap pest control products were tested against Ixodes scapularis nymphs on sod, pachysandra, landscaping stones and pinebark wood-chips in a laboratory study. High mortality (91–100%) was obtained with the silica-based desiccant Drione and Safer's insecticidal soap (SIS) treatments except for SIS treated woodchips. SIS and Drione contain 0.2 and 1% pyrethrins, respectively. SIS may be absorbed by the woodchips and not picked up by the nymphs as mortality decreased to 78%. Diatomaceous earth and Dri-die reduced nymphs by only 10–41%; neither desiccant contains insecticides. Nymphal mortality increased 15–17% after 20 or 100 ml of water was sprayed over sod plugs treated with SIS or Drione. The addition of isopropyl alcohol (ROH) to SIS increased the efficacy of SIS against nymphal I. scapularis on treated sod plugs but not on treated landscaping substrates. Drione, SIS, SIS-ROH and chlorpyrifos 50WP treated landscaping stones and pinebark woodchips resulted in 88–95% and 72–96% nymphal mortality, respectively. Unexpectedly, these substrates and treatments affected tick movement as well. Effective pest control products applied to xeric landscaping substrates present in maintained beds and borders near wooded areas could deter tick movement and provide significant levels of tick control.     

Population studies of the beech leaf mining weevil (Rhynchaenus fagi) in Ireland and Scotland

Abstract. 1. Population budgets for Rhynchaenus fagi, based for the most part on samples of beech leaves taken in June, were constructed for a 10-year period (Northern Ireland) and a 3-year period (Scottish borders).
2. There were years of sustained population growth and sustained decline, but not enough evidence to suggest a cycle. Similar population levels were found at both sites in all but one year.
3. Key factors were associated with the adult stage, although egg mortality may also make a significant contribution to population change.
4. Unknown sources of mortality embodied in the residual mortality were also suspected of acting in a density dependent manner, compensating for variation in parasitism.
5. Death rate of larvae within mines was related to May temperature in Northern Ireland, but not so clearly in Scotland.     

Use of Lethal Control to Reduce Habituation to Blank Rounds by Scavenging Birds

Abstract Scavenging bird deterrence frequently fails due to habituation. We demonstrated such habituation by gulls and corvids to blank rounds used in a dawn-to-dusk regime at a landfill site in southern England. We then combined blank rounds with live rounds and shot birds whenever they attempted to land. Gull numbers declined significantly despite only 1.9% of the population being shot. Corvid numbers returned to precontrol levels despite 52.7% of the population being shot. We suggest that shooting reduces gull habituation to blank rounds but is ineffective at reducing habituation by corvids.     

Phylogenetic relationships in the iguanid lizard genus Liolaemus: multiple origins of viviparous reproduction and evidence for recurring Andean vicariance and dispersal

Phylogenetic relationships within the iguanid lizard genus Liolaemus are investigated using 1710 aligned base positions (785 phylogenetically informative) of mitochondrial DNA sequences, representing coding regions for eight tRNAs, ND2, and portions of ND1 and COL Sixty new sequences ranging in length from 1736 to 1754 bases are compared with four previously reported sequences. Liolaemus species form two well-supported monophyletic groups of subgeneric status, Liolaemus and Eulaemus. These subgenera appear to have separated at least 12.6 million years ago based on the amount of molecular evolutionary divergence between them. Hypotheses that species occurring in the Andes, west of the Andes, and east of the Andes, each comprise distinct monophyletic groups are independently rejected statistically. The shortest estimate of phylogeny suggests mat Liolaemus originated either in the Andes or the eastern lowlands. Numerous evolutionary shifts have occurred between the Andes, and the eastern and western lowlands, suggesting recurring vicariance and dispersal. Species occurring at high elevations or high latitudes usually have viviparous reproduction. Depending on whether parity mode is considered reversible in Liolaemus , the most parsimonious reconstruction supports at least six independent origins of viviparity or at least three gains followed by three losses of viviparity among die 60 Liolaemus lineages examined.     

Evidence for non-random spatial positioning of migrating smolts (Salmonidae) in a small lowland stream

1. The ontogenetic development of anadromous salmonids includes downstream emigration of immature individuals from freshwater towards the marine environment. Although this migration of juvenile salmonids (smolts) may be associated with severe mortalities, only limited attention has been paid to the spatial positioning of smolts in small streams. 2. Using a novel approach, this study examined the vertical and horizontal positioning of brown trout and Atlantic salmon smolts while performing downstream migration in a small lowland stream. 3. Pre‐smolts of indigenous and hatchery‐reared (F1) brown trout (Salmo trutta), and two different populations of Atlantic salmon (S. salar), were tagged with passive integrated transponder (PIT) tags and subsequently released upstream of an antenna array consisting of five circular swim‐through PIT antennas. Antennas were positioned in order to determine whether the migrating smolts were bottom or surface oriented, and if they were oriented towards the mid‐channel or the stream bank. 4. During the smolt emigration period, data describing both the detection of the migrating fish and the amount of water passing through the antennas were collected. This was accomplished in order to determine if the fish were performing active positioning behaviour independently of the vertical and horizontal discharge distributions in the stream. 5. The results showed that the smolts migrated in a non‐random spatial pattern independently of the stream discharge distributions. Vertically, the indigenous brown trout and the Atlantic salmon demonstrated a preference for the bottom orientated positions. In contrast, the distribution of the F1 brown trout was not different from the discharge distribution. The latter observation suggests random vertical positioning, which may be indicative of inferior migratory performance. Horizontally, all tested smolt populations strongly preferred the mid‐channel positions. 6. The discharge‐corrected preferences for certain spatial positions suggest that smolt emigration is not entirely a matter of passive displacement in lowland streams. 7. Anthropogenically altered channels may inhibit or delay downstream emigration of smolts resulting in increased mortalities. Given that the smolts in this study actively selected spatial positions in the mid‐channel and near the bottom, it is suggested that deep, mid‐channel furrows may be used to help guide migrating smolts past adverse habitats in lowland streams.