bluuebunny/crossref_metadata_2025 huggingface dataset:
A double blind parallel group placebo controlled comparison of sedative and amnesic effects of etifoxine and lorazepam in healthy subjects
Authors: Micallef J. , Soubrouillard C. , Guet F. , Le Guern M. E. , Alquier C. , Bruguerolle B. , Blin O.
Published: March 2003

This paper describes the psychomotor and amnesic effects of single oral doses of etifoxine (50 and 100 mg) and lorazepam (2 mg) in healthy subjects.

Forty‐eight healthy subjects were included in this randomized double blind, placebo controlled parallel group study. The effects of drugs were assessed by using a battery of subjective and objective tests that explored mood and vigilance (Visual Analog Scale), attention (Barrage test), psychomotor performance (Choice Reaction Time) and memory (digit span, immediate and delayed free recall of a word list).

Whereas vigilance, psychomotor performance and free recall were significantly impaired by lorazepam, neither dosage of etifoxine (50 and 100 mg) produced such effects.

These results suggest that 50 and 100 mg single dose of etifoxine do not induce amnesia and sedation as compared to lorazepam.
The role of the interaction between endogenous opioids and nitric oxide in the pathophysiology of ethanol‐induced gastric damage in cholestatic rats
Authors: Nahavandi Arezo , Mani Ali Reza , Homayounfar Homayoun , Akbari Mohammd Reza , Dehpour Ahmad Reza
Published: March 2003

Interaction between endogenous opioids and nitric oxide (NO) has been shown in different biological models and pharmacological evidence suggest that opioids can induce NO release in endothelium as well as in neural cells. Cholestasis is associated with NO overproduction. The reason for increased NO synthesis is not clearly known but it can potentiate development of gastric mucosal damage in cholestatic subjects. Based on increased plasma levels of endogenous opioids and existence of NO overproduction in cholestasis, the present experiments were performed to investigate the role of interaction between endogenous opioids and NO in generation of ethanol‐induced gastric damage in cholestatic rats. Cholestasis was induced by surgical ligation of bile duct and sham‐operated rats served as controls. The animals received either 20 mg/kg of naltrexone or saline for 6 days and then were fasted and received L‐arginine (200 mg/kg), NG‐nitro‐L‐arginine methylester (L‐NAME; 2, 5 and 10 mg/kg) or saline. The ethanol‐induced gastric mucosal damage was significantly more severe in cholestatic rats than in sham‐operated animals (115 ± 12 mm2 vs. 72 ± 11 mm2, P < 0.05). L‐NAME significantly enhanced the development of gastric mucosal lesions in sham‐operated rats. But in cholestatic animals, L‐NAME decreased and L‐arginine enhanced the severity of gastric damage. Pretreatment of animals with naltrexone decreased severity of gastric mucosal damage in cholestatic rats. Concurrent administration of naltrexone with L‐arginine was protective against ethanol‐induced gastric damage in both normal and cholestatic groups. Administration of naltrexone with L‐NAME had the same effect in cholestatic and control rats and increased severity of gastric damage. Plasma levels of NO2− + NO3− were significantly higher in cholestatic rats than control animals (72 ± 6 μM vs. 39 ± 3 μM, P < 0.05). Pretreatment of animals with naltrexone significantly reduced plasma levels of NO2− + NO3− in cholestatic animals, but not in control rats (33 ± 6 μM vs. 32 ± 4 μM). The protective effect of L‐NAME against gastric damage in cholestatic rats can be explained by inhibition of NO overproduction and it seems that interaction between opioids and NO may have an important role in generation of NO overproduction and gastric complications in cholestatic rats.
Vanadium pharmacokinetics and oral bioavailability upon single‐dose administration of vanadyl sulfate to rats
Authors: Azay Jacqueline , Brès Janine , Krosniak Miroslaw , Teissedre Pierre‐Louis , Cabanis Jean‐Claude , Serrano Jean‐Jacques , Cros Gérard
Published: March 2003

Vanadium pharmacokinetic parameters and oral bioavailability were determined after administration of vanadyl sulfate, an antidiabetic agent, to male Wistar rats. An optimal sampling design was used over a 21‐day period; vanadium was measured in blood by atomic absorption spectrophotometry (AAS). After i.v. bolus injection (3.025 mg V/kg body weight), a three‐compartment model was fitted to the data. Mean (± SD) half‐lives were 0.90 ± 0.56 hours, 24.8 ± 14.5 h and 201 ± 74 h, respectively, for the three phases observed. Vanadium clearance averaged 37.6 ± 15.8 mL/h. Initial volume of distribution was 2.43 ± 1.22 L/kg whereas total volume of distribution was 25.4 ± 3.9 L/kg; these values largely exceeded body weight (i.e. 300 g), in agreement with a great uptake and retention of vanadium in tissues. After oral gavage administration (15.12 and 7.56 mg V/kg body weight), vanadium disposition was best described by a three‐compartment model, with absorption appearing to occur by a zero‐order rate. This process lasted 10.3 ± 1.3 h and 10.9 ± 1.1 h for the two dosage levels, respectively. Half‐lives corresponding to the terminal log‐linear part of the curve were 173.5 ± 1.6 h and 172 ± 6 h (Bayesian estimates). No dose‐dependency was observed for any of the parameters determined. Absolute bioavailabilities, with reference to the i.v. administration, were 12.5% and 16.8% when determined from AUCmod. Bioavailability appeared to be higher than generally stated in the literature.
Isoniazid pharmacokinetics in children according to acetylator phenotype
Authors: Rey Elisabeth , Gendrel Dominique , Treluyer Jean Marc , Tran Agnès , Pariente‐Khayat Ann , D'Athis Philippe , Pons Gérard
Published: March 2003

The pharmacokinetics of isoniazid (INH) was studied in children (0–196 months old) according to their acetylator phenotype, estimated from the metabolic acetyl INH/INH molar plasma concentration ratio (MR) measured 3 h after INH oral administration. There were 17 slow (MR < 0.48) and 17 fast acetylators (MR ≥ 0.48). The mean apparent plasma clearance was significantly lower, the mean apparent volume of distribution higher and the half‐life longer in the slow acetylator group (C1, 0.298 ± 0.099 L/h/kg; Vd, 1.56 ± 0.65 L/kg; t1/2, 3.88 ± 01.89 h) than in the fast acetylator group (Cl, 0.528 ± 0.234 L/h/kg; Vd, 1.06 ± 0.45; t1/2, 1.64 ± 1.1 h). The half‐life decreased with age.

An impaired isoniazid elimination was suggested in children less than three months old, which may be in favour of an individual dose adjustment in this population.
Randomized, comparative, double‐blind study of amlodipine vs. nicardipine as a treatment of isolated systolic hypertension in the elderly
Authors: Mounier‐Véhier Claire , Jaboureck Olivier , Emeriau Jean‐Paul , Bernaud Corine , Clerson Pierre , Carre Alain
Published: March 2003

A 90‐day, multicenter, randomized, double‐blind, parallel‐group study was conducted to compare the efficacy of amlodipine (once a day) with nicardipine (two to three times a day), in the treatment of isolated systolic hypertension (ISH) in the elderly. Patients (n = 133) aged ≥60 years, with ISH were randomized to receive either amlodipine 5 mg/day, or nicardipine 60 mg/day (titrated if necessary to 10 mg/day and 100 mg/day, respectively) for 90 days. Efficacy was assessed by measuring office blood pressure (BP), and 24‐h ambulatory blood pressure monitoring (ABPM). The two treatments substantially and comparably reduced office systolic blood pressure (SBP) and pulse pressure (PP), and also produced a slight decrease in diastolic blood pressure (DBP). Amlodipine reduced SBP, as assessed by ABPM, to a significantly greater extent than nicardipine. Both treatments were well‐tolerated. The sustained effect of amlodipine, compared with nicardipine, was reflected in its significantly greater antihypertensive activity, particularly during the nocturnal period, as assessed by ABPM. The study demonstrates that once a day dose of amlodipine is an effective antihypertensive treatment for elderly ISH patients.
Insulin resistance, a new target for nitric oxide‐delivery drugs
Authors: Cook Stéphane , Scherrer Urs
Published: March 2003

In the Western hemisphere, the incidence of insulin resistance and its complications has been growing rapidly and is reaching epidemic proportions. Over the past decade, evidence has accumulated, indicating that nitric oxide (NO) plays a key role in the regulation of metabolic and cardiovascular homeostasis. Defective endothelial nitric oxide synthase (eNOS) driven NO synthesis causes insulin resistance, arterial hypertension and dyslipidemia in mice, and characterizes insulin‐resistant humans. On the other hand, stimulation of inducible nitric oxide synthase (iNOS) and NO overproduction in mice, may also cause metabolic insulin resistance, suggesting a Yin–Yang effect of NO in the regulation of glucose homeostasis. Here, we will review the evidence for this novel concept, and thereby provide the conceptual framework for the use of NO‐delivery drugs and pharmacological agents that modulate the bioavailability of endogenously produced NO for the treatment of insulin resistance.
Impairment of vascular and platelet levels of nitric oxide and cyclic guanosine‐3′,5′‐monophosphate in cyclosporin A‐induced hypertensive rats
Authors: Santiago Margarida , Reis Flávio , Almeida Luís , Alcobia Teresa , Dionísio Joaquim , Teixeira Frederico
Published: March 2003

ABSTRACT The therapeutic use of the immunosuppressive agent cyclosporin A (CsA) is associated with arterial hypertension and increased risk of thromboembolism. Impaired endothelium‐mediated relaxation is one of the main hypotheses explaining the CsA‐induced vascular hyper‐reactivity. Since nitric oxide (NO) modulates both vascular and platelet activity, we studied the effects of CsA on the levels of arterial and platelet NO as well as 3′,5′‐cyclic guanosine monophosphate (cGMP) levels which are influenced by NO. An animal model of CsA‐induced hypertension was used. Wistar rats were treated with a clinically relevant, oral dose of 5 mg/kg CsA, daily, for 4 weeks. CsA increased both systolic and diastolic blood pressures compared to non‐treated rats (P < 0.01). Nitrite, a NO metabolite, decreased in the entire aorta wall (30%, P < 0.05) and in the aorta wall without the endothelial layer (70 %, P < 0.05) in CsA‐treated vs. control groups. cGMP content was also decreased in the CsA‐treated group (67%, P < 0.01) vs. control. Taken together, these results suggest a defect on the endothelial NO generation, acceleration of breakdown and/or consumption of NO, as well as marked alterations directly on cGMP metabolism. Conversely, platelet nitrite and cGMP content significantly increased in the CsA‐treated rats, which was also observed in in vitro studies of platelet nitrite release following CsA treatment. This suggests a platelet self‐regulation mechanism against CsA‐induced platelet hyper‐reactivity, which, in turn, could compensate vascular impairment.
Effects of aspirin on N‐α‐tosyl l‐arginine methyl ester [TAME]‐esterase induced contractions on rat aorta in vitro
Authors: Gurib Fatmah Bibi Housnah , Subratty Anwar Hussein
Published: March 2003

The present study was designed to investigate whether N‐α‐tosyl l‐arginine methyl ester [TAME]‐esterase activation could be the result of endothelial dysfunction. Thoracic aorta from rats was mounted in an organ bath containing Krebs solution. Intact and endothelium denuded aortic strips were challenged with different concentrations of TAME (10−15–10−1 m). The effects of aspirin, a cyclo‐oxygenase pathway inhibitor, were also studied on [TAME]‐esterase induced contraction on rat aorta strips. Our results showed that aspirin definitely blocked TAME‐esterase induced contractions on rat aortic strips.

In conclusion, the present work supported the hypothesis that [TAME]‐esterase induced contraction in rat aorta in vitro was mediated through release of prostaglandin(s) as a result of endothelial dysfunction.
Effects of endurance training on heart rate and blood pressure variability
Authors: Uusitalo Arja L. T. , Laitinen Tomi , Väisänen Sari B. , Länsimies Esko , Rauramaa Rainer
Published: March 2003

Purpose: To study the influences of a 1‐year controlled, randomized endurance exercise training period on heart rate (HR) and blood pressure variability in a representative sample of Finnish men in their late middle age.

Methods and results: Subjects were 140 sedentary men aged 53–63 years. The men were randomized into two identical groups: an intervention (EX) and a reference (CO) group. One hundred and twelve of them remained in the final analysis (EX: n=59, CO: n=53). EX trained for 30–60 min three to five times a week with the intensity of 40–60% of maximal oxygen consumption. In EX, 1 year of regular exercise training increased oxygen consumption at respiratory compensation threshold by 11% (P ≤ 0·001) in a maximal cardiorespiratory test. Total power and very low frequency power of R–R interval variability (ms2) tended to increase in the EX group by 26 and 42% and to decrease in the CO group by 13 and 10% (interaction P<0·05 and P<0·01), respectively. There were no significant changes in blood pressure variability.

Conclusion: Regular low‐ to moderate‐intensity exercise training could retard the decli‐ning tendency in cardiac autonomic nervous function in older men during 1 year.
Validation of a newly developed B‐mode image‐processing technique versus wall‐tracking ultrasound for the study of wall mechanics in small‐calibre arteries
Authors: Vernhet Hélène , Demaria Roland , Juan Jean M. , Oliva‐Lauraire Marie C. , Quéré Isabelle , Gariépy Jérôme , Sénac Jean P. , Dauzat Michel
Published: March 2003

Purpose: To validate a newly developed image‐processing technique for the assessment of arterial wall compliance and distensibility from non‐invasive B‐mode ultrasound compared with the invasive wall‐tracking technique.

Materials and methods: Arterial wall compliance and distensibility coefficient were measured invasively by wall‐tracking with an ultrasonic transducer implanted on the vessel wall, and non‐invasively by automatic processing of B‐mode ultrasound images, with a dedicated workstation and software (IO^ 3·1, IO^DP, Paris). Measurements were performed in the normal aorta of five animals, and upstream, at the stent level, and downstream from the stent in eight other animals (immediately after stenting in six, and 3 months later in four), for a total of 35 paired measurements.

Results: There was no significant difference between the two techniques for compliance but there was a significant difference in diameter (P<0·005) and distensibility (P<0·05) as external ultrasound measured the inner diameter, while wall‐tracking measured the outer diameter. Agreement between the two methods as assessed by the Bland–Altman approach was acceptable for aortic diameter, compliance and distensibility.

Conclusion: Automatic processing of B‐mode ultrasound images is a reliable non‐invasive technique to assess the compliance of small‐calibre arteries.
Female gender increases stiffness of elastic but not of muscular arteries in type I diabetic patients
Authors: Ahlgren Å. Rydén , Sundkvist G. , Sandgren T. , Länne T.
Published: March 2003

The reason for the particularly increased risk for cardiovascular complications in diabetic women is still unclear. We have previously found decreased distensibility of elastic arteries in type I diabetic women, indicating increased cardiac load, not seen in type I diabetic men, which might be one contributing factor. Whether the effect of gender is different in muscular arteries in type I diabetic patients has not been assessed. As estimates of arterial distensibility we measured stiffness (β) and pressure strain elastic modulus (Ep) in the muscular common femoral artery using echo‐tracking sonography in 30 women (mean age 34 years, range 20–61) and 26 men (mean age 38 years, range 22–56) with type I diabetes. The results were compared with those of 89 healthy individuals of corresponding age and gender and with previously published results from elastic arteries in these patients obtained at the same occasion. The internal common femoral diameter was significantly decreased in both diabetic men and women. In sharp contrast to the highly significant decreased distensibility of the elastic abdominal aorta and common carotid artery in the type I diabetic women, the distensibility of the common femoral artery did not clearly differ between patients and controls, neither for women nor for men. Thus, the gender difference in changes of arterial distensibility found in elastic arteries was absent or far less obvious in the femoral artery. In conclusion, female gender seems to affect the mechanical properties of elastic, but not of large muscular arteries in type I diabetic patients. Thus, putative gender differences in arterial changes in type I diabetes are to be sought in elastic rather than muscular arteries.
Forest Fragmentation and Alien Plant Invasion of Central Indiana Old‐Growth Forests
Authors: BROTHERS TIMOTHY S. , SPINGARN ARTHUR
Published: March 2003

Abstract: We assessed alien plant invasion of old‐growth forest islands in rural central Indiana by means of paired sample sites along “warm” (south and west) edges and “cool” (north and east) edges in each of seven forest remnants. In general, the fragments appeared resistant to alien invasion; alien species richness and frequency dropped sharply inward from forest edges, and forest interiors were relatively free of aliens. However, aliens were more diverse and more frequent on warm edges than on cool ones. The main factor limiting invasion is probably low light availability in forest interiors, though limited dispersal and low disturbance levels may also be important. We suggest that invasion is discouraged by the edge response of the forests themselves: development of a dense wall of bordering vegetation that reduces interior light levels and wind speeds. The most successful invaders are mostly escaped ornamentals or other species not commonly found in adjoining fields. They can be expected to become more prominent in the future, but their spread at the landscape scale may be slowed by the “oceans” of cropland surrounding these forest islands.
Determining Minimum Habitat Areas and Habitat Corridors for Cougars
Authors: Beier Paul
Published: March 2003

I simulated population dynamics of cougars to predict the minimum areas and levels of immigration needed to avoid population extinction caused by demographic and environmental stochasticity for a period of 100 years. Under most plausible parameter values, the model predicted very low extinction risk in areas as small as 2200 km2, and (in the absence of immigration) increasing risk as area decreased below 2200 km2. If as few as one to four animals per decade could immigrate into a small population, the probability of population persistence increased markedly. Thus a corridor for immigration will benefit a small population in an area where further loss of habitat will occur.

The model was applied to the cougar population in the Santa Ana Mountain Range of southern California (2070 km2, with about 20 adults). Field data support the model’s conclusion that this population is demographically unstable. There will be a high risk of extinction if the habitat is reduced to currently protected and connected areas (1114 km2). A movement corridor allowing immigration from the adjacent population and intra‐range corridors would greatly enhance the prognosis. However, the last corridor for immigration has been degraded by recent human activity. Within the mountain range, cougars recently became extinct in a 75 km2 habitat fragment recently isolated by development, and cougars will become extinct in another 150 km2 of habitat if a proposed housing project occludes a critical corridor. Radio tracking has confirmed use of this and other important corridors.

Neither the model nor the field data alone would have much influence in the face of development pressure; together they have stimulated interest in restoring and protecting critical corridors in this range. Nonetheless, the long‐term prognosis for this populations is bleak, because 22 local governments review potential impact on a case‐by‐case basis. Effective land‐use planning must be spatially explicit and regional in scope. Because cougars need corridors and because telemetered cougars can quickly identify movement corridors, cougar research is an efficient and appropriate way to inject biological data into such planning efforts.
Ecological Benefits of the Conservation Reserve Program
Authors: Dunn Christopher P. , Stearns Forest , Guntenspergen Glenn R. , Sharpe David M.
Published: March 2003

The Conservation Reserve Program was initiated in 1985 to reduce soil loss on highly erodible agricultural land. This stated objective of the program has been quite successful. However, there are other unintentional yet significant ecological benefits to the program that merit evaluation. These benefits include the reversal of landscape fragmentation, maintenance of regional biodiversity, creation of wildlife habitat, and favorable changes in regional carbon flux. These and other benefits should be used by policy makers and federal officials to maintain the program even after enrollment expectations have been achieved.
Channel Migration and Vegetation Patterns in the Southeastern Coastal Plain
Authors: Shankman David
Published: March 2003

Channel migration is a major determinant of vegetation patterns in the tower bottomlands of the southeastern‐coastal plain of the United States. Lateral channel movement creates new surfaces by point‐bar deposition and the filling in of abandoned channels. The new surfaces are rapidly colonized by flood‐tolerant, opportunistic species. Sediment deposited during subsequent years’ flooding raises young surfaces, making them less susceptible to inundation and more suitable for the establishment of less flood‐tolerant species that eventually replace the early arrivals. The continued presence of the young forest communities depends primarily on the formation of new surfaces by channel migration and the development of shallow swamps. Shallow swamps are formed when channel obstructions force water into the adjacent bottomlands, destroying forest stands and allowing the establishment of early successional species. Many of the streams in the southeastern coastal plain have been channelized. Stabilized channels limit the development of shallow swamps and preclude the formation of point bars and oxbow lakes. Therefore, the largest‐scale natural disturbance mechanism and the most important factor controlling spatial heterogeneity in the lower bottomland sites has been eliminated. Channelization will likely result in a shift towards a homogeneous floodplain forest composed of later successional mesic species that occupied the outer floodplain before channelization.
Environmental Perceptions and Social Relations in the Mapimí Biosphere Reserve
Authors: Kaus Andrea
Published: March 2003

Biosphere reserves were developed in part to integrate conservation with regional development objectives and thereby to include protected areas within the resource management of inhabited areas. The Mapimí Biosphere Reserve of Durango, Mexico, provides an example of the difficulties confronted by protected‐area managers in implementing the biosphere reserve concept, especially when groups with vested interests in the site perceive the same environment differently. The reserve supports a long‐term research program on the ecology of the Chihuahuan Desert and has succeeded in protecting an endangered species of tortoise with the cooperation of the local residents. However, coexisting forms of land tenure and resource management, including extensive cattle grazing prevent complete protection of the core zone, and the gap between basic and applied research has hindered the reserve’s managers and researchers from developing their good public relations into a plan for regional conservation.
Relationship of Breeding System to Rarity in the Lakeside Daisy (Hymenoxys acaulis var. glabra)
Authors: DeMauro Marcella M.
Published: March 2003

The breeding system of a rare Great Lakes endemic, the lakeside daisy (Hymenoxys acaulis var. glabra), was investigated when plants from a remnant Illinois population produced no seeds for over 15 years. To determine if the Lakeside daisy was self‐incompatible, 20 plants from two populations, Illinois and Ohio, were selfed and outcrossed. Seed/ovule ratios were compared among the different treatments and the location of the incompatibility reaction was identified. Lakeside daisy was found to be self‐incompatible (sporophytic). The last Illinois population was effectively extinct because the remaining plants belonged to the same mating type (Ne = 1) and only produced seeds when outcrossed to the Ohio plants. Cross‐incompatibility was also observed among Ohio plants, suggesting that within large populations, compatible mating types may be rare locally. In addition, inbreeding depression (lower seed/ovule ratios in inbred than in outcrosses) was observed after one generation of inbreeding. Small populations of self‐incompatible species are vulnerable to extinction if the number of self‐incompatibility alleles, either as a result of a bottleneck or of genetic drift, falls below tbe number needed for the breeding system to function. Recovery protocols based on these genetic considerations were developed and implemented in 1988 when Lakeside daisy populations were established at three Illinois nature preserves.
Rarity in Neotropical Forest Mammals Revisited
Authors: Dobson F. Stephen , Yu Jinping
Published: March 2003

The identification of rare species is an important goal in conservation biology. Recent attempts to classify rare species have emphasized dichotomies in such characteristics as local population density, area of distribution, and degree of ecological specialization. In particular, Arita et al. (1990) dichotomized 100 Neotropical forest mammals according to local population density and area of distribution. Among these species of mammals, mean body mass was significantly associated with local population density and area of distribution. We argue that the effects of body mass should be removed before species are classified with respect to rarity. We re‐evaluated the data on Neotropical mammal species, using regression analyses to remove the effects of body mass on population density and area of distribution, followed by analysis of residuals. This new method resulted in substantial changes in the dichotomous classification of rare species. We combined the analysis of regression residuals with a ranking procedure that assumed that local population density and area of distribution were equally important in their effects on rarity. The new ranking technique produced another different classification of the rarity of the Neotropical forest mammal species. A graphical analysis showed that ranked species differed substantially in their degree of rarity, and in the importance of local population density, area of distribution, or both, to their degree of rarity. The ranking method allows the species of greatest concern to be singled out, it can be modified to include additional variables such as niche breadth, and it should be helpful for making conservation decisions.
Plant Taxonomic Research, with Special Reference to the Tropics: Problems and Potential Solutions
Authors: PARNELL J.
Published: March 2003

Abstract: The rate of completion of tropical floras is both very low and very slow. Research funding councils could correct this at relatively little cost by adequately funding existing projects. The position of European universities as centers for taxonomic research and training has declined in relative terms since 1959. Nevertheless, at present there are still many more plant taxonomists and specimens in Europe and the U.S. than there are in the tropics. Over the past thirty years, European universities have retained their very large collections of tropical material, but they now have a small and aging population of tropical taxonomists to work on them; over the same period there has been a huge increase in the numbers of taxonomists and plant taxonomic institutions in the tropics. Nowadays tropical countries have the personnel and institutions, but not the reference specimens. Institutes in Europe and the U.S. should act to correct these deficiencies by offering scholarships to taxonomists from the tropics to work in Europe or the U.S. Scholarships for European and U.S. taxonomists to work in the tropics must also be offered so as to optimize the use of their collections. A similar but lesser problem with a similar solution exists in the temperate zone, where the major taxonomic resources occur in regions where most is known about the flora, while regions where little is known have few resources. Contract‐based funding for sections of major taxonomic projects would almost certainly stimulate the university taxonomic infrastructure.
Extinction, Colonization, and Metapopulations: Environmental Tracking by Rare Species
Authors: Thomas C.D.
Published: March 2003

Extinction and metapopulation theories emphasize that stochastic fluctuations in local populations cause extinction and that local extinctions generate empty habitat patches that are then available for recolonization. Metapopulation persistence depends on the balance of extinction and colonization in a static environment. For many rare and declining species, I argue (1) that extinction is usually the deterministic consequence of the local environment becoming unsuitable (through habitat loss or modification, introduction of a predator, etc.); (2) that the local environment usually remains unsuitable following local extinction, so extinctions only rarely generate empty patches of suitable habitat; and (3) that colonization usually follows improvement of the local environment for a particular species (or long‐distance transfer by humans). Thus, persistence depends predominantly on whether organisms are able to track the shifting spatial mosaic of suitable environmental conditions or on maintainance of good conditions locally.
Water, Endangered Fishes, and Development Perspectives in Arid Lands of Mexico
Authors: Contreras‐B. Salvador , Lozano‐V. M. Lourdes
Published: March 2003

Nearly half of Mexico is arid or semiarid, with scarce waters. At least 92 springs and 2500 km of river have dried in this area. Surface waters have diminished, and phreatic waters are sinking deeper, provoking intrusion of saline waters and salinization of agricultural wells in Sonora, reversing phreatic circulation in the Comarca Laguenera, allowing arrival of arsenic to agricultural waters, and threatening metropolitan Torreón. There are nearly 200 species of freshwater fishes in this region, 120 under some threat, 15 extinct through human impact. As of 1985, an average of 68% of species was eradicated in local fish faunas. Finally, salinization of the lower Rio Bravo del Norte has replaced 32 native fish of fresh or slightly brackish water with 54 mainly marine or highly salt‐tolerant species; the salinization threatens all uses of water. Some marine fishes invade up to 400 km upstream. Pollution is strong, and fish kills have been reported. These low‐quality and scarce waters comprise future resources for cities such as Monterrey, which, along with its border twin cities, is expected to double its human population by 2010. Redesign of regional development is urgently needed, in keeping with the real availability of water. All water use should be equal to or less than lower recharge averages; norms of integral basin management should rely on criteria of high‐use efficiency, recuperation, recycling, and reutilization. Also necessary are reduced pollution and increased treatment of residual waters. Innovative environmental vision is especially essential in light of expectations for development through the North American Free Trade Agreement, the Border Integral Environmental Plan, industrial expansion, and the modernization and internationalization of the northern Mexican border belt. These all conflict with the high priority recently decreed for species conservation by the Mexican Act, creating the National Committee on Knowledge and Use of Biodiversity.
Environmental Dependency of Inbreeding Depression: Implications for Conservation Biology
Authors: Pray Leslie A. , Schwartz James M. , Goodnight Charles J. , Stevens Lori
Published: March 2003

Inbreeding depression is environmentally dependent, such that a population may suffer from inbreeding depression in one environment but not another. We examined the phenotypic responses of 35 inbred (F = 0.672) lineages of the red flour beetle Tribolium castaneum in two different climatic environments. We found a significant environmental effect on males but not females. More important, we found that the rank fitness order of lineages differs between environments; lineages of high fitness in one environment may have low fitness in another environment. This change in rank is evident in a significant genotype‐by‐environment interaction for inbreeding depression for both females and males. These results suggest that even if we know the average environmental effect of inbreeding depression in a population, for any particular lineage measurements of inbreeding depression in one environment may not predict the level of inbreeding depression in another environment. Conservation biologists need to be aware of the environmental dependency of inbreeding depression when planning wildlife refuges or captive propagation programs for small populations. Ideally, captive propagation programs should maintain separate lineages for release efforts. Refuge design programs should consider maintaining a range of habitat types.
An Age‐Structured Demographic Model for the Endangered Stephens’ Kangaroo Rat
Authors: Price Mary V. , Kelly Patrick A.
Published: March 2003

Effective conservation of endangered species often is hampered by inadequate knowledge of demography. We extracted information on survival and fecundity from an 18‐month, live‐trapping study of Dipodomys stephensi, and from this we developed an age‐structured demographic model to assess population viability. Adult Stephens’ kangaroo rats persisted longer than juveniles, and adult females persisted longer than adult males. Disappearance rates were high in the first months after initial capture. Thereafter, the fraction of animals persisting decreased slowly and in an approximately linear fashion on a semilogarithmic scale, suggesting age‐independent mortality factors such as predation. Juvenile persistence did not differ substantially between two years of strikingly different rainfall. Onset of breeding followed the start of winter rains. Length of the breeding season, average number of litters per female, and the fraction of first‐year females breeding were much greater in the year of higher rainfall. We propose a birth‐pulse demographic model for D. stephensi that distinguishes juvenile and adult age classes. Temporal environmental variation can be modeled adequately with a constant survivorship schedule and variable fecundity determined by yearly precipitation. Several issues should be resolved, however, before conservation decisions are based on the model. Better estimates of juvenile survivorship are critical, the quantitative relationship between precipitation and fecundity must be determined, and the potential for density dependence and source‐sink population dynamics must be evaluated.
Forest‐Dwelling Vertebrate Faunas and Natural Fire Regimes in British Columbia: Patterns and Implications for Conservation
Authors: Bunnell Fred L.
Published: March 2003

Structure of native vertebrate faunas within 12 different forest types were related to features of the natural fire regime. Relations between faunal structure and fire regime followed patterns expected if faunas were adapted to fire regimes. Proportions of species breeding early in succession tended to increase with increasing fire size or burn rate (ha/year; p = 0.03); those breeding late in succession tended to decrease (p = 0.04). As fire size increased, proportions of species breeding in cavities decreased (p < 0.01). Proportions of species using downed wood to breed increased as the interval between fires increased and downed wood accumulated (p < 0.01). Forestry practices to maintain biodiversity should mimic natural disturbance patterns, which differ across forest types. Implications for management to maintain vertebrate diversity are summarized in terms of the silvicultural system employed, the size of patches logged, the rate of timber removal, and the appropriate degree of connectivity among unlogged patches.
Inferring Threat from Scientific Collections
Authors: Burgman Mark A. , Grimson Roger C. , Ferson Scott
Published: March 2003

Exact formulas for the probability of extinction or change in the conservation status of species are described for data based on frequency of sighting. These formulas generalize an expression previously described for the probability of extinction from (binary) sighting data. The formulas will be used in contexts where sightings are recorded as frequencies, such as when observations are aggregated in time. We argue that computing the probability of extinction or change in conservation status will be most useful for setting conservation priorities and in screening large data sets contained in museum and herbarium collections and in biological resource inventories.
Ecological Biodiversity of Marine Nematodes in Samples from Temperate, Tropical, and Deep‐Sea Regions
Authors: Boucher Guy , Lambshead P. John D.
Published: March 2003

Little is known about the biodiversity of free‐living nematodes. We have attempted to provide baseline information about the natural diversities (those not influenced by pollution) that might be expected in six biotopes. Seventeen marine nematode data sets consisting of 197 samples were standardized to allow a comparison of alpha diversity, or sample diversity, from temperate estuarine, tropical sublittoral, temperate sublittoral, bathyal, abyssal, and hadal biotopes, which were selected on criteria of depth and latitude. The diversity analysis methods we employed were rarefaction curves; three weighted diversity indices of species richness, SR, H′, and ES(X); and two equitability indices, J′ and V. Diversity was significantly different in the six biotopes. The weighted indices of species richness were more capable of resolving differences between the biotopes than were the equitability indices, whose large standard errors suggested that they were more influenced by local, small‐scale ecological factors. This suggests that species richness is a better measure than equitability for large‐scale comparisons of biotopes or regions. The ES(X), which is robust to sample size variations, was more efficient than the weighted indices of species richness, which were easily influenced by sample size. There was a nonlinear relationship between depth and diversity with the bathyal and abyssal biotopes displaying the highest diversity. The tropical sublittoral biotope was not more diverse than the temperate sublittoral biotope. The lowest diversities were found in the physically challenging temperate estuarine and hadal biotopes.
Ecological Impact of Economic Development on Sardinian Herpetofauna
Authors: Van Rooy Peter T.J.C. , Stumpel Anton H.P.
Published: March 2003

The link between ecology and economies is manifest over the world as a result of long‐term processes. But because these processes are long term, it is hard to prove the link. On Sardinia serious economic development was late to arrive, having occurred only over the last few decades. As a case study, research was carried out for 10 years on the state of nature as well as the economic growth in one of the least developed areas abutting the Gulf of Orosei on the east coast. Based on research and lasting attention to political affairs concerning the project, we formulate general recommendations for the area. In 1995, the Italian Government will be asked by the European Government to undertake serious steps to save endemics (especially herpetofauna) of Europe's last pristine areas.
Genetic Analysis of the Endangered Island Endemic Malacothamnus fasciculatus (Nutt.) Greene var. nesioticus (Rob.) Kearn. (Malvaceae)
Authors: Swensen Susan M. , Allan Gerard J. , Howe Melanie , Elisens Wayne J. , Junak Steven A. , Rieseberg Loren H.
Published: March 2003

Isozyme, randomly amplified polymorphic DNA, and ribosomal DNA analyses were used to evaluate the genetic distinctness and diversity of the endangered island endemic Malacothamnus fasciculatus var. nesioticus (Santa Cruz Island bush mallow). Analysis of amplified DNA profiles and electrophoretic data indicates that var. nesioticus is genetically distinct from other varieties within the species. No isozyme or amplified DNA variation was detected among individuals of nesioticus populations, but restriction site analysis of ribosomal DNA revealed the presence of three closely related genotypes within one of the nesioticus populations. Apparent clonal structuring was found in both nesioticus populations and in one mainland population, var. nuttallli. Results from these analyses provide the background necessary for the design of conservation efforts with recovery goals that insure the long‐term survival of Malacothamnus fasciculatus var. nesioticus.
Assessing the Conservation Value of New Zealand’s Offshore Islands
Authors: Mortimer Russell , Sharp Basil , Craig John
Published: March 2003

New Zealand has over 500 offshore islands. Many consist of relatively pristine wilderness and contain a disproportionately large amount of New Zealand’s biological wealth. Increased demand for recreation has increased the pressure to develop these areas. Although the New Zealand public has shown widespread support for the preservation and safeguarding of both wilderness areas and endangered species, economic values attached to the benefits of preservation are not known. Using a telephone survey, we found evidence that the public attaches significant value to the conservation of Little Barrier Island. The results show that these values are influenced by different levels and sources of prior information.
Genetic Criteria for Establishing Evolutionarily Significant Units in Cryan’s Buckmoth
Authors: Legge John T. , Roush Richard , Desalle Rob , Vogler Alfred P. , May Bernie
Published: March 2003

Buckmoths (Hemileuca spp.) are day‐flying saturniid moths with diverse ecologies and host plants. Populations that feed on Menyanthes trifoliata, known commonly as Cryan’s buckmoths, have been found in only a few bogs and fens near eastern Lake Ontario in New York and near Ottawa in Ontario, Canada. Because of their unique ecological traits, geographic isolation from other Hemileuca populations, and the small number of sites they occupy, there is concern that the Cryan’s buckmoth populations are phylogenetically distinct and should be protected. The Cryan’s buckmoths have not yet been taxonomically described and do not appear to have clear distinguishing morphological characters. Both molecular genetic traits (allozymes and mitochondrial DNA sequences) and an ecologically based character (host performance) were investigated to determine whether these populations possess fixed diagnostic characters signifying genetic differentiation from other eastern Hemileuca populations. Such differences would merit separate conservation management as an evolutionarily significant unit. Our studies showed that the Cryan’s buckmoths clearly belong to the Hemileuca maia species group, but they could not be readily distinguished from other members of that group by means of molecular genetic techniques. There were no fixed differences in alleles or haplotypes distinguishing any of the populations or species, suggesting recent divergence. Nonetheless, in the host‐plant performance experiment only the Cryan’s buckmoth larvae were able to develop on M. trifoliata, a significant difference from other Hemileuca larvae tested. The Cryan’s buckmoth appears to be unique in host performance and warrants protection and management us an evolutionarily significant unit. In cases such as this where groups appear to have recently diverged, investigations into ecologically significant traits may provide indicators of conservation significance as reliable as molecular genetic markers.
Disease Risks of Wildlife Translocations
Authors: Cunningham Andrew A.
Published: March 2003

Threats posed to conservation programs by the translocation of pathogens along with the translocation of host species are being increasingly recognized. However, publications on this subject have appeared primarily in veterinary literature which often is not read widely by those who fund, plan, or carry out the majority of wildlife translocations. The problem of wildlife disease and translocations has been written about in detail recently, but in almost all cases has been limited to exploring the immediate effects of pathogens on the target species. I discuss the possible adverse effects of wildlife translocations that result from disease transmission. In addition to examining the effects on target species, I discuss the possible direct and indirect effects of parasite translocations on sympatric species and on the evolution of ecosystems in the long‐term. To reduce potential disease risks presented by wildlife translocations, I propose some guidelines for hygiene and quarantine procedures and for monitoring the parasite status of both captive and free‐living animals.
Relationships and Genetic Purity of the Endangered Mexican Wolf Based on Analysis of Microsatellite Loci
Authors: García‐Moreno Jaime , Matocq Majorie D. , Roy Michael S. , Geffen Eli , Wayne Robert K.
Published: March 2003

The Mexican wolf (Canis lupus baileyi), an endangered subspecies of gray wolf, was native to parts of Mexico and the southwestern United States. Currently, only a few individuals, if any, exist in the wild, so planned reintroduction programs must use captive‐raised wolves. In only one captive population, however, designated the certified lineage, are all the founders (n = 4) known to be obtained from a wild population of Mexican wolves. Two captive populations were founded from individuals of uncertain ancestry and have not been included in the species survival plan. To preserve genetic diversity and reduce inbreeding so that fitness will be maintained, it would be desirable to include these two captive populations in the breeding program if it could be shown that they were derived from a wild population similar to the certified lineage. We compared allele frequencies of 10 hypervariable microsatellite loci in Mexican gray wolves with those found in a sample of 42 domestic dogs, 151 northern gray wolves, and 142 coyotes to determine if uncertified Mexican wolves had specific markers from these animals. We analyzed pairwise genetic distance measures to demonstrate that the three captive populations of Mexican gray wolves were closely related to each other and distinct from dogs and northern gray wolves. The three captive populations are genetically more similar to each other than to any other population of dog or wolf‐like canid, and they shared alleles that were rare in other canids. The genetic distance between them is similar to that between closely spaced populations of northern gray wolves. As a group, moreover, they are the most genetically distinct population of North American gray wolf. Therefore, the three captive populations could potentially be interbred to augment the genetic diversity of the certified lineage. Source individuals for reintroduction should be derived from the captive Mexican wolf population rather than populations of captive or wild northern gray wolves.