bluuebunny/crossref_metadata_2025 huggingface dataset:
Species richness of marine Bryozoa in the continental shelf and slope off Argentina (south‐west Atlantic)
Authors: Gappa Juan López
Published: March 2003

Abstract. A total of 246 marine bryozoan species was recorded within an area of the south‐west Atlantic between 35° and 56°S, and between the coast of Argentina and 50°W. The distribution pattern of benthic stations surveyed during the most important cruises in the area shows that the sampling effort has been biased towards southern shelf areas off Santa Cruz and Tierra del Fuego, as well as around the Malvinas (Falkland) islands. The littoral zone, Patagonian gulfs and the continental shelf off Chubut, Río Negro and Buenos Aires state received less attention, and should be surveyed more intensively in the future. Only 2% of the species can be regarded as non‐indigenous, all of them inhabiting biofouling communities in harbour environments. With the exception of some thoroughly surveyed localities, the number of species recorded for different areas of the coast, shelf and slope is estimated to be just a small fraction of the actual number of species present. A distinct diversity gradient was found, with species‐rich stations located only in the southern shelf. Highest diversity occurred in shelf areas dominated by coarse sediments, and along a high‐productivity shelf‐break front. A remarkable decrease in species richness was found in inner and middle shelf areas off Chubut, Río Negro and Buenos Aires state. This pattern may be related to the Pacific origin of the Magellanic fauna, since the diversity of bryozoans is higher in the Pacific than in the Atlantic Ocean. The trend of species richness is, however, overemphasized by the fact that the least diverse faunistic assemblage occurs in areas where surveys have been relatively less frequent. An up‐to‐date checklist of species recorded for the study area is included.
Past distribution and ecology of the cork oak (Quercus suber) in the Iberian Peninsula: a pollen‐analytical approach
Authors: Carrión J. S. , Parra I. , Navarro C. , Munuera M.
Published: March 2003

Abstract.  This study presents pollen‐analytical data from continental and offshore Iberian Peninsula sites that include pollen curves of Quercus suber, to provide information on the past distribution and ecology of the cork oak (Q. suber). Results centre on a new pollen record of Navarrés (Valencia, eastern Spain), which shows that the cork oak survived regionally during the Upper Pleistocene and was important during a mid‐Holocene replacement of a local pine forest by Quercus‐dominated communities. This phenomenon appears linked to the recurrence of fire and reinforces the value of the cork oak for reforestation programmes in fire‐prone areas. In addition to Navarrés, other Late Quaternary pollen sequences (Sobrestany, Casablanca‐Almenara, Padul, SU 8103, SU8113, 8057B) suggest last glacial survival of the cork oak in southern and coastal areas of the Peninsula and North Africa. Important developments also occur from the Late Glacial to the middle Holocene, not only in the west but also in the eastern Peninsula. It is suggested that, in the absence of human influence, Q. suber would develop in non‐monospecific forests, sharing the arboreal stratum both with other sclerophyllous and deciduous Quercus and Pinus species.
Competitive interactions between overstorey proteas and sprouting understorey species in South African mountain fynbos
Authors: Vlok J. H. J. , Yeaton R. I.
Published: March 2003

Abstract.  Previous studies in the mountain fynbos of South Africa have demonstrated that short fire cycles favour the establishment of dense covers of understorey sprouters while longer fire intervals enable the establishment from seed of overstorey proteas and the formation of a overstorey. One consequence of these differences between fire cycle lengths is the effect that understorey sprouters and an overstorey protea canopy have on species richness. In the case of short fire intervals, species richness is decreased while longer intervals between fires allow species richness to decrease or increase depending on the patchiness of the overstorey canopy. Such results are suggestive of competitive effects between understorey sprouters and overstorey canopy proteas. In this study, data were collected from several pyric successional stages in mountain fynbos to study the effect of overstorey proteas on the growth and flowering of understorey sprouters since the last fire. Data were also collected to determine the effect that understorey sprouters had on the establishment and fecundity of overstorey protea species. Competitive interactions between overstorey proteas and sprouting understorey species were evident at all the sites studied. The vegetative growth and seed production of understorey sprouters, which grew under a canopy of overstorey proteas during the current interfire period, were significantly lower than that for plants growing in the open. In addition, the postfire growth and seed production of understorey sprouters were significantly lower for individuals, which grew under an overstorey protea canopy during the previous fire cycle, than for those individuals which grew in the open. The fecundity of overstorey proteas, which grew near understorey sprouters, was lower than that of plants which grew in the open. This effect was evident for up to the first 15 years after a fire. However, not all understorey sprouters affected the overstorey proteas equally. Also, seedlings of overstorey proteas established significantly less successfully in close proximity to understorey sprouters after a fire than in the open or under proteas. Finally, the results demonstrate that complex species‐specific, understorey–overstorey interactions are important in mountain fynbos. For example, some overstorey species depend on trophically similar species to reduce potential competition from understorey sprouters for their successful establishment at a site.
Geometric constraints and spatial pattern of species richness: critique of range‐based null models
Authors: Laurie Henri , Silander John A.
Published: March 2003

Abstract. Does the shape of a biogeographical region influence its spatial patterns of species richness? A complete answer must include careful distinction between the distribution of a species, which is a complex geometric object, and the range of a species, which is relatively simple, especially when reduced to one dimension. We consider range‐based models of species richness, in particular range overlap counts in one dimension, for which we give a unified mathematical treatment via the joint probability P(m,l) of midpoints and lengths of ranges. We discuss a number of difficulties, in practice and in principle, using range‐based models, and show that the so‐called mid‐domain effect, a proposed null model for the effect of geometric constraint, is qualitatively a property of all biologically realistic models based on range overlap counts. As such, range‐based models provide little insight into understanding or explaining biogeographical patterns in species richness. We characterize the quantitative null model for range overlap counts in one dimension, for which we give a simple and direct field test based on P(m,l). We apply this test to a large clade in a complete bioregion (the Proteaceae of the Cape Floristic Region): geometric constraint does not explain the spatial pattern in this case. We show that any geometric constraint on species richness, including range overlap counts, must act via edge effects. Thus, to understand biogeographical patterns, an understanding of the effects and consequences of edges is fundamental.
Sigma receptors: from discovery to highlights of their implications in the cardiovascular system
Authors: Monassier Laurent , Bousquet Pascal
Published: March 2003

Sigma receptors are the targets of many ligands, of which some (the haloperidol for instance) are psychoactive, and of substances known to have antiarrhythmic effects (amiodarone and clofilium). They are involved in a variety of cardiovascular functions, such as the regulation of cardiac contractility and rhythm and the regulation of coronary and peripheral arterial vasomotricity. This short review will focus on some aspects regarding the ligands, the binding sites, the intracellular coupling and the cardiovascular functions of these enigmatic receptors.
Lidocaine diminishes arrhythmia by Leiurus quinquestriatus quinquestriatus venom in rats
Authors: Purali Nuhan , Yagcioglu Suha
Published: March 2003

The venom from the scorpion Leiurus quinquestriatus quinquestriatus has previously been shown to alter the excitability of the neural and skeletal muscle preparations. The present study was undertaken to explore the effects of the venom in cardiac potential signals at the animal, tissue and the cell level in rats hearts.

In anaesthetised animals Leiurus quinquestriatus quinquestriatus venom (LqV) 100 μg applied intravenously reduced the heart rate by 13%, and evoked some abnormal waveforms in the electrocardiogram (ECG). Lidocaine injection (0.02 μg) restored the waveform of the ECG. However, the sinus rhythm resumed only when Atropine (2.5 μg) was applied in addition to previously administered Lidocaine.

In isolated atria, LqV (10–2 mg/mL) exposure abolished the sinus rhythm and decreased the spontaneous rate by 38%, and increased the contraction amplitude by 85%, and duration of the contractions by 17%. The gross electrical activity of the preparation and the duration of the individual atrial muscle action potential were prolonged by 150% and 186%, respectively. In isolated papillary muscle, LqV evoked irregular contractions, and the duration of the action potential was increased about 15‐fold. The effects by LqV in the action potential were present when calcium channels were blocked but not when extracellular sodium was substituted. Lidocaine (75 nM) antagonised the effects by LqV in isolated atria and papillary muscle.

It was concluded that the lethal cardio‐toxic effects by LqV were mainly due to its direct action in myocardial cells, and partly to an alteration in the autonomous nervous activity.
ICH Topic: The draft ICH S7B step 2: Note for guidance on safety pharmacology studies for human pharmaceuticals
Authors:   ICH Expert Working Group Topic Leaders:, Bode Gerd , Olejniczak Klaus
Published: March 2003

During the last ICH Expert Working Group meeting for Safety Pharmacology in February 2002 in Brussels, the appended step 2 S7B document on QT Prolongation was signed off. This paper will now be published by the three agencies. The comment period will be 6 months. Nevertheless, the EU and EFPIA would be very appreciative of comments received before the end of May 2002, in order to start the discussion on how this step 2 document should be modified.

In addition, everybody is requested to share data that could support the evaluation process of all methods addressed in this document.

The EWG appreciates every support.
Time‐effect profile of antihypertensive agents assessed with trough/peak ratio, smoothness index and dose omission: an ambulatory blood pressure monitoring study with trandolapril vs. quinapril1
Authors: Radauceanu Anca , Virion Jean‐Marc , Boivin Jean‐Marc , Zannad Faiez
Published: March 2003

The duration of action of antihypertensive drugs may be assessed by several methods using ambulatory blood pressure monitoring (ABPM).

The aim of this double‐blind, randomized study was to compare the time‐effect profile of once daily Trandolapril (Tra) 2 mg vs. Quinapril (Qui) 20 mg in 92 patients with mild‐to‐moderate hypertension.

All patients received placebo during a 30‐day run‐in period followed by 2 months of active therapy and 1‐day medication omission. ABPM was conducted on each period. 24 h antihypertensive coverage was assessed by trough:peak ratio (T/P) and smoothness index (SI) methods. Residual lowering of blood pressure after single‐blind, 1 day medication omission was investigated as the SBP/DBP 48‐h trough effect.

There were no statistically significant differences between treatment groups in the mean SBP/DBP peak or trough effect.

Individual T/P were not normally distributed and had very large variations explained by BP random‐ and activity‐related fluctuations. Group T/P were 0.85 for Tra and 0.62 for Qui.

The SI values were normally distributed and not statistically different between the two treatment groups.

After dose omission, Qui was ineffective at 48‐h trough while Tra retained a significant effect (SBP/DBP= –3.4/–4.3 mmHg) and this difference was even greater in ABPM‐responders.

Comparison of the trough:peak ratios and smoothness indexes of Tra and Qui failed to show any statistically significant difference on 24‐h antihypertensive coverage. Nevertheless, residual lowering of blood pressure at 48‐h trough suggests that Tra had a longer duration of action than Qui.
The therapeutic potential of NO‐NSAIDs
Authors: Wallace John L. , Soldato Piero Del
Published: March 2003

NSAIDs, including those that are selective for cyclooxygenase‐2, are among the most widely used drugs. However, these drugs produce significant side effects in the gastrointestinal and cardiorenal systems, which greatly limit their utility. In recent years, a new type of anti‐inflammatory agent has been developed that appears to offer significant advantages over conventional and Cox‐2‐selective NSAIDs. No‐NSAIDs are derivatives of conventional NSAIDs, which are able to release nitric oxide over prolonged periods of time. The combination of balanced inhibition of the two main isoforms of COX with controlled release of nitric oxide yields a series of drugs that exert anti‐inflammatory and analgesic activities in a wide range of settings, and have markedly reduced gastrointestinal and cardiorenal toxicity. Recent clinical trials of NO‐NSAIDs have provided a ‘proof of concept’ that is completely consistent with pre‐clinical characterization of these compounds.
Loss of size‐selectivity at histamine‐induced exudation of plasma proteins in atopic nasal airways
Authors: Greiff Lennart , Andersson Morgan , Erjefält Jonas S. , Svensson Christer , Persson Carl G.A.
Published: March 2003

Plasma proteins occur in the airway lumen in inflammatory airway diseases. This study tests the hypothesis that airway microvascular‐epithelial exudation of plasma proteins, as induced by a non‐injurious inflammatory mediator, is characterized by loss of size‐selectivity. Using a nasal pool‐device, the nasal mucosa of 10 allergic individuals, without current disease, was sequentially exposed to saline and histamine (40 and 400 μg ml–1). Nasal lavage fluid and blood‐levels of albumin (69 kD) and α2‐macroglobulin (720 kD) were determined. Histamine produced concentration‐dependent exudation of albumin and α2‐macroglobulin. The albumin/α2‐macroglobulin concentration ratio of the saline lavage fluid (baseline) was 40 ± 19. However, at the histamine challenges the ratios were 25 ± 3 and 22 ± 2, respectively, which did not differ from that of circulating plasma (22 ± 2). We conclude that there is minor and size‐selective luminal entry of plasma proteins at baseline. However, at concentration‐dependent exudative responses to histamine, plasma proteins enter the airway lumen without being sieved. These data indicate that inflammatory stimulus‐induced extravasation, lamina propria distribution and paracellular epithelial passage of plasma occur with minimal size‐selectivity. Inferentially, the full immunological capacity of plasma proteins may readily be made available at the surface of human intact airway mucosa.
Integrating Biological and Sociological Concerns in Endangered Species Management: Augmentation of Grizzly Bear Populations
Authors: Maguire Lynn A. , Servheen Christopher
Published: March 2003

To help the recovery of a remnant grizzly (Ursus arctos horribilis) population in the Cabinet‐Yaak Ecosystem in northwestern Montana, wildlife managers have proposed augmenting the population with bears translocated from a larger population. This proposal has raised fears that translocated bears might endanger human lives and livelihoods. To reconcile the biological needs of this grizzly population with the socioeconomic needs of the human population, we used a combination of decision analysis, consensus of expert opinion, and tradeoff analysis to design a pilot scale augmentation program to enhance grizzly viability while minimizing bear‐human conflicts. The analysis incorporated objective and subjective information on the movements, behavior, and reproductive potential of different age‐sex classes elicited from a group of experts on grizzly biology and management. This information was used to rank the different age‐sex classes according to three criteria: retention of translocated bears in the Cabinet‐Yaak Ecosystem, conflict with human activities, and relative contribution to grizzly population growth. Subadult females were high in reproductive contribution and moderate in conflict, adult females were moderate in reproductive contribution and low in conflict, adult males were low in reproductive contribution and low in conflict, and subadult males were very low in reproductive contribution and high in conflict. These rankings were insensitive to minor changes in the expert judgments used in the analysis. Because the goals of maximizing population growth and minimizing conflict could not be met with any age‐sex class, we used tradeoff analysis to establish minimum thresholds for retention and maximum thresholds for conflict and to characterize the experts’ preferences among different combinations of reproductive contribution and conflict. A reranking of the age‐sex classes based on the tradeoff analysis showed that 4‐ to 8‐year‐old females were most preferred. The analysis revealed that no more than one out of three translocated bears was likely to remain within the Cabinet‐Yaak Ecosystem and that as many as one out of four might seriously conflict with human activities. These results prompted an intensive public education program to muster support for the augmentation program before any translocations were attempted.
Biodiversity and Ecological Redundancy
Authors: WALKER BRIAN H.
Published: March 2003

Abstract: This paper addresses the problem of which biota to choose to best satisfy the conservation goals for a particular region in the face of inadequate resources, Biodiversity is taken to be the integration of biological variability across all scales, from the genetic, through species and ecosystems, to landscapes. Conserving biodiversity is a daunting task, and the paper asserts that focusing on species is not the best approach. The best way to minimize species loss is to maintain the integrity of ecosystem function. The important questions therefore concern the kinds of biodiversity that are significant to ecosystem functioning. To best focus our efforts we need to establish how much (or how little) redundancy there is in the biological composition of ecosystems. An approach is suggested, based on the use of functional groups of organisms defined according to ecosystem processes. Functional groups with little or no redundancy warrant priority conservation effort. Complementary species‐based approaches for maximizing the inclusion of biodiversity within a set of conservation areas are compared to the functional‐group approach.
Where Should Nature Reserves Be Located in the Cape Floristic Region, South Africa? Models for the Spatial Configuration of a Reserve Network Aimed at Maximizing the Protection of Floral Diversity
Authors: REBELO A. G. , SIEGFRIED W. R.
Published: March 2003

Abstract: The SLOSS debate can only be resolved by considering the optimal spatial configuration of a nature‐reserve system. Only when target species have been identified by such considerations can the size of the constituent reserves be determined. We explored two null models for a spatial configuration of reserves in the Cape Floristic Region, South Africa, based on the distribution of species in the family Proteaceae (Angiospermae: Rosidae). In the first model, reserves (12 × 13 km grid squares) were assigned at random for comparison with existing, proposed, and theoretically ideal configurations. In the second model, the theoretically ideal reserve configuration was constructed using the first model as a preassigned configuration. Two methods were used to iteratively select a reserve from the grid system: richness of unprotected species (species‐richness algorithm), and the sum of the rarity indexes for each unprotected species (rarity algorithm). Both algorithms yielded configurations requiring fewer reserves than those contained in proposed or existing configurations, although neither algorithm was perfect. The existing reserve configuration performed no better than the random model, assuming that the principal goal is protection of all species. We confirm that the best approach to designing a reserve configuration that maximizes the protection of species richness is to identify areas of high endemism and richness within particular biogeographical regions.
Hypothesis Concerning the Causes of the Disappearance of Boreal Toads from the Mountains of Colorado
Authors: Carey Cynthia
Published: March 2003

Recent reports of world‐wide declines and extinctions of amphibian populations have raised questions about the relation of environmental change to the demise of certain amphibian species. Between 1974 and 1982, 11 populations of boreal toads (Bufo boreas boreas) in the West Elk Mountains of Colorado totally disappeared. The apparent cause of extinction of these toads was infection with the bacteria Aeromonas hydrophila. In this paper, the presence of disease in declining populations of these toads is used in conjunction with a variety of data from the literature to formulate a working hypothesis for explaining the cause of the decline of this species, and perhaps others:

Some environmental factor or synergistic effects of more than one factor changes sufficiently to cause sublethal “stress”;

This stress directly causes suppression of the immune system, or indirectly causes immunosuppression by effecting elevated secretion of adrenal cortical hormones;

Immunosuppression, coupled with the apparent effect of cold body temperatures on the ability of immune systems of ectothermic animals to fight disease, leads to infection by Aeromonas or other infectious agents and to subsequent death of individuals and extinction of populations.
Biogeography of Recently Extinct Marine Species: Implications for Conservation
Authors: Vermeij Geerat J.
Published: March 2003

At least fifteen marine and coastal animal species have become extinct since the end of the Pleistocene. Analyses of the number of marine biogeographical provinces occupied by these species show that, contrary to the prevailing view that extinction is usually associated with a small range, at least five species (33%) had large ranges encompassing parts of two or more provinces. At least eight species occurred in areas that served as geographical refuges for taxa during the Pliocene and early Pleistocene. These refuges, in which primary planktonic productivity is generally very high, include the northwestern Atlantic and North Pacific. Extinctions in the northwestern Atlantic (four species) may be partly responsible for the subsequent success of human‐introduced species in subtidal and open‐coast intertidal habitats. Regions of high productivity deserve priority among marine areas to be protected from overexploitation and habitat destruction.
The Olympic Goat Controversy: A Perspective
Authors: SCHEFFER VICTOR B.
Published: March 2003

Abstract: Mountain goats (Oreamnos americanus) introduced into Olympic National Park are multiplying and causing soil erosion and changes in floral composition. Park managers want the goats removed or, if necessary, killed. But the Fund for Animals, a national humane society, argues that the present goat population should be left undisturbed as a replacement of a presumed indigenous stock that disappeared long ago. (I side with the park managers.) The debate underscores the value of both logic (or reason) and sentiment (or emotion) in making wildlife management decisions.
Forest Fragmentation and Bird Extinctions: San Antonio Eighty Years Later
Authors: Kattan Gustavo H. , Alvarez‐López Humberto , Giraldo Manuel
Published: March 2003

We report on the extent of bird extinctions at San Antonio, a fragmented cloud forest site in the western Andes of Colombia, for which surveys dating back to 1911 and 1959 an available. In 1911, 128 forest bird species were present in San Antonio. Twenty‐four species had disappeared by 1959, and since then 16 more species have gone locally extinct, for a total of 40 species or 31% of the original avifauna. We analyzed patterns of extinction in relation to geographic distribution and foraging guilds. We found that in this montane assemblage, being at the limits of the altitudinal distribution was the main correlate of extinction; 37% of the extinct species were at the upper limit of their altiudinal distribution. We also found that the most vulnerable guilds were the understory insectivores and the large canopy frugivores. Our study illustrates the extent of bird extinctions that are currently undocumented in the highly fragmented forests of the northern Andes, where the absence of baseline information on the fauna of unaltered forests is a limiting factor for the development of conservation and management plans. We stress the need to establish data bases and long‐term monitoring projects for the Andean fauna.
Agricultural Land Use and Grassland Habitat in Illinois: Future Shock for Midwestern Birds?
Authors: Warner Richard E.
Published: March 2003

Populations of many common grassland birds in the midwestern United States have been declining in recent decades. These declines have been particularly pronounced in Illinois, where the prairie has been severely fragmented and disturbed by farming. This article describes transitions in agricultural land use in Illinois since the early 1800s, their effects on grassland habitat, and responses by avifauna. Furthermore, factors affecting nesting by birds are considered from a landscape perspective for a study area in central Illinois during the period (1973–1981) when cropping became so intensive that grassland persisted primarily as linear edges. There was a paucity of avifauna nesting on grassy edge habitats on the study area, with a mean of 2.2 nests per ha, representing only eight species. Nest densities and species diversity were highest on study plots where grassland was nearby, where cover types were heterogeneous, and where there were corridors connecting plots to the surrounding landscape. Nest success was variable from year to year, and for Ring‐necked Pheasants (Phasianus colchicus) the average annual nest success on edge habitats was positively related to the total amount of grassy cover (including hay and small grains) per nesting pleasant. The findings suggest that it is too simplistic to conclude that linear habitats, compared to field settings, are “predator traps.” Responses by birds to habitat deteríoration in Illinois may foretell future trends elsewhere in North America where farming practices are becoming more intensive.
Diagnosing Units of Conservation Management
Authors: Vogler Alfried P. , Desalle Rob
Published: March 2003

Species‐oriented conservation programs attempt to analyze and maintain intra‐specific variation in order to maximally preserve biological diversity. The “evolutionarily significant unit” has become an operational term for a group of organisms that should be the minimial unit for conservation management. No generally accepted definition for this term exists that would be the basis for the evaluation of these units in practical conservation situations. Currently, taxonomic decisions in species conservation are mostly based on the biological species concept. But the universal application of criteria of reproductive isolation or phenetic similarity to delimit conservation units is problematical. We favor a definition for evolutionarily significant units based on patterns of variation. In the theoretical framework of the phylogenetic species concept, conservation units are delimited by characters that diagnose clusters of individuals or populations to the exclusion of other such clusters. Characters are used for cladistic analysis to infer hypotheses of the phylogenetic relationships of individuals, and differentiated populations are diagnosed using population aggregation analysis. Characters can be based on genetic, morphological, ecological, or behavioral information, provided they are inferred to be heritable. The use of cladistics and population aggregation analysis has the potential to make the evaluation of evoluntionarily significant units objective and testable, an important consideration in politically controversial cases. Our cladistic approach is demonstrated by the evaluation of potential conservation units in the endangered tiger beetles Cicindela dorsalis and C. puritana.
Sustainable Use of the Tropical Rain Forest: Evidence from the Avifauna in a Shifting‐Cultivation Habitat Mosaic in the Colombian Amazon
Authors: Andrade Germán I. , Rubio‐Torgler Heidi
Published: March 2003

We carried out a one‐year study of the avifauna along a regeneration gradient created by indigenous shifting cultivation in the Colombian Amazon rain forest. Regenerating one‐hectare crop fields, from 1 to 17 years after abandonment, and undisturbed understory sites were compared in a sample effort of 4323 net hours. We made 878 captures of 103 species belonging to 11 trophic groups. Differences in species richness and number of individuals captured between regenerating areas and primary forest were low. A comparison of similarity indices among the sites for each habitat type showed no consistent differences, suggesting similar levels of local heterogeneity. Similarity indices calculated between sites of different‐aged habitats, however, showed that young secondary growth at less than 10 years of abandonment was least similar to other sites, whereas old secondary growth between 13 to 17 years of abandonment, and forest understories, had the most similar avifauna. Two trophic groups were absent from the samples of the forest interior, and the abundance of the other nine varied among sites of regeneration. We conclude that slash and burn agriculture represents a high‐intensity, small‐magnitude disturbance to the forest avifauna. Large changes occur when the crop field is established and last until about 10 years after abandonment. Our data suggest that abandoned crop fields older than this age mimic the natural patch dynamics of the forest, making this type of agriculture an example of a potentially sustainable use of tropical forests, at least from the standpoint of its impact on bird communities.
The Effects of Selective Logging on Inbreeding in Shorea megistophylla (Dipterocarpaceae) from Sri Lanka
Authors: Murawski Darlyne A. , Gunatilleke I.A.U. Nimal , Bawa Kamaljit S.
Published: March 2003

The mating system of Shorea megistophylla, an endemic canopy tree from Sri Lanka, was quantified by allozyme analysis of progeny arrays using a mixed‐mating model. Two adjacent populations were compared: one in forest that was selectively logged about 20 years ago, and the other in undisturbed primary forest. The selectively logged population had a lower multilocus outcrossing rate (tm, = 0.71) compared to that of the undisturbed forest (tm = 0.87). Only the progeny from the logged population showed evidence of either biparental inbreeding or Wablund effect, and the genotypic frequencies violated the assumptions of the mixed‐mating model. Apomixis was detected in one isolated tree in the Royal Botanical Garden in Peradeniya by a multilocus test of progeny genotypic frequencies relative to the maternal genotype. However, significant levels of apomixis were not discerned in the natural (logged and unlogged) populations. These findings indicate that a reduction in population density of S. megistophylla following selective logging can significantly elevate the proportion of seeds produced through inbreeding. Adventive embryony may also increase in isolated trees that lack the chance to outcross.
Relating Patterns of Land‐Use Change to Faunal Biodiversity in the Central Amazon
Authors: Dale Virginia H. , Pearson Scott M. , Offerman Holly L. , O'Neill Robert V.
Published: March 2003

Large‐scale deforestation is threatening the diversity of tropical forests. Given the paucity of data on life‐history characteristics of tropical species, methods are needed to identify those species susceptible to extirpation following forest fragmentation. The approach developed in this paper provides a method to examine potential effects of forest fragmentation on biodiversity considering both land‐use changes and traits of susceptible species. Based on certain behavioral characteristics, the effects of forest fragmentation in the Brazilian Amazon were projected for nine groups of animals. The taxonomically diverse species were characterized by gap‐crossing ability and area requirements. The probability of local extinction due to destruction of habitat over a 40‐year period was estimated for these animal groups under three scenarios of land‐use practice, projected with a computer model. These scenarios include the typical land use of central Rondônia, Brazil, and two extremes of land‐use practice that bracket the range of possible agricultural land‐use changes. Animals with gap‐crossing ability proportional to area requirements respond similarly to fragmentation, regardless of their taxonomic affiliation. The available habitat for those species is proportional to the amount of remaining forest under all three agricultural management scenarios. In contrast, species that have large area requirements but that will cross only small gaps are more adversely affected by forest fragmentation. The available habitat for such species is reduced at a rate disproportionately greater than the rate of forest clearing. For a tropical frog, the effects of forest fragmentation were evaluated considering not only gap‐crossing ability and area requirement but also specialized habitat requirements and edge effects. For the worst‐case scenario of land management, gap‐crossing ability and area requirements of the tropical frog imply that only 60% of the forest remaining after seven years of management is suitable habitat. Considering breeding habitat requirements and possible edge effects further reduces the suitable habitat to 39% of the remaining forest. These reductions in the proportion of suitable forest area are likely to change with rate and spatial pattern of forest loss.
Population Viability Estimates: Theory and Practice for a Wild Gorilla Population
Authors: Harcourt A.H.
Published: March 2003

The logic of demographic modeling, the apparent simplicity of its quantifiably substantiated answers, and the ready availability of software correlate with increasing use of demographic modeling as the means of applying biology to the conservation of potentially endangered populations. I investigated that use by considering a small population (about 300 individuals) of a large, forest‐dwelling mammal of the tropics, the Virunga gorilla (Gorilla gorilla) of Zaire, Uganda, and Rwanda. Because censuses of forest populations are so inaccurate and data on variance of some parameters takes so long to collect, models might not be broadly applicable. Therefore, simple demographic indices of potential extinction should replace sophisticated models. The current best index could be problematic, however, because it is based on detecting adult mortality, perhaps the most difficult demographic parameter to measure. Models of the Virunga gorilla population that incorporate aspects of demographic heterogeneity valuably indicate genetic and demographic persistence for several hundred years. Deterministic change in habitat is a greater threat than stochastic demographic variation, and yet our ecological ignorance is such that we could not begin to model the consequences of removal of even the main food plant. We must add to our ability to model outcomes of demographic perturbation a far greater understanding of the processes by which the perturbations occur. Demography allows us to model demographic response to demographic change, but we usually need ecology to tell us how the threat produced the demographic change in the first place. In a time of change, accurate prediction requires ecological understanding of process as well as demographic understanding of outcome.
The Reliability of Using Population Viability Analysis for Risk Classification of Species
Authors: Taylor Barbara L.
Published: March 2003

I examine whether or not it is appropriate to use extinction probabilities generated by population viability analyses, based on best estimates for model parameters, as criteria for listing species in Red Data Book categories as recently proposed by the World Conservation Union. Such extinction probabilities are influenced by how accurately model parameters are estimated and by how accurately the models depict actual population dynamics. I evaluate the effect of uncertainty in parameter estimation through simulations. Simulations based on Steller sea lions were used to evaluate bias and precision in estimates of probability of extinction and to consider the performance of two proposed classification schemes. Extinction time estimates were biased (because of violation of the assumption of stable age distribution) and underestimated the variability of probability of extinction for a given time (primarily because of uncertainty in parameter estimation). Bias and precision in extinction probabilities are important when these probabilities are used to compare the risk of extinction between species. Suggestions are given for population viability analysis techniques that incorporate parameter uncertainty. I conclude that testing classification schemes with simulations using quantitative performance objectives should precede adoption of quantitative listing criteria.
A Value‐Informed Framework for Interdisciplinary Analysis: Application to Recovery Planning for Snake River Salmon
Authors: Hyman Jeffrey B. , Wernstedt Kris
Published: March 2003

Economic and social variables, in addition to biological variables, are often critical forces in directing recovery planning for threatened and endangered populations. Although including these variables in scientific analyses for recovery planning may be important, there is little agreement on how to integrate the relevant disciplines. The dilemma associated with interdisciplinary collaboration is that, while a diversity of values and perspectives is unavoidable, this diversity stands as a barrier to agreement on an integrative research approach. We describe a general framework for interdisciplinary analysis designed to support recovery planning that does not rely on choosing a single interdisciplinary approach. Rather, it uses value conflicts potentially arising in an interdisciplinary setting to select a diverse set of scientific approaches relevant to a particular conservation effort. We apply this framework to recovery planning for threatened Snake River chinook salmon (Oncorhynchus tshawytscha) and examine the implications of conflicts over the acceptability of institutional change, technological solutions, and transferability of recovery effort across groups responsible for the current status of the species.
Rapid Build‐up of Fish Biomass in a Caribbean Marine Reserve
Authors: Roberts Callum M.
Published: March 2003

Marine reserves, where fishing is excluded, have been argued to be an effective means of managing complex reef fisheries and of protecting populations of species vulnerable to overfishing. The argument rests on predictions of increases in abundance and size of fishes after the elimination of fishing mortality, which in turn leads to greater egg production per unit of reef and greater export via pelagic dispersal to fishing grounds. This study reports responses of fish populations to area closure in a small Caribbean marine reserve surrounding the island of Saba in the Netherlands Antilles. Part of the reserve has been closed to fishing since 1987, and the remainder is subject only to light fishing. Fish populations were visually censused and sizes of individuals present estimated from counts in fished and unfished areas of the marine park in 1991 and 1993. For four of five commercially fished families, biomass was greater in the unfished area than in the fished. Predictions of greater abundance and size in the unfished area were upheld for many of the species observed. Between 1991 and 1993 overall biomass of commercially important families increased 60%, based largely on increases in abundance between years. The predatory snappers (Lutjanidae) increased 220%. Fishing pressure in Saba was reduced between censuses due to changing employment opportunities. It was notable that populations increased in both fished and unfish ed areas of the park, and the latter is probably an effect of this reduced fishing intensity. Reserves have been suggested as refuges for species vulnerable to overexploitation, especially groupers. Despite protection from fishing, the Saba Marine Park has low population densities of such species, perhaps due to a lack of supply of larvae from unprotected source areas. My study shows that target fish populations may respond swiftly to reductions in fishing pressure and that reserves could play an important role in fisheries management. But protection of vulnerable species is only likely to be successful if networks of reserves are established throughout species ranges to link larval supply and settlement areas.
Landscape Patterns of Florida Scrub Jay Habitat Use and Demographic Success
Authors: Breininger David R. , Larson Vickie L. , Duncan Brean W. , Smith Rebecca B. , Oddy Donna M. , Goodchild Michael F.
Published: March 2003

Remote sensing and geographical information systems are used to analyze landscapes important to species of conservation concern. The accuracy of the methods depends on how closely habitat mapping classes are linked to population demography. Habitat use by Florida Scrub Jays (Aphelocoma c. coemlescens) was quantified using circular plots. Habitat variation was mapped using high‐resolution aerial photography on a site where all Florida Scrub Jays were color‐banded. Nest site selection, nest success, yearling production, and breeder survival were measured within Florida Scrub Jay territories. Habitat use was lowest in areas without scrub oaks or areas within 136 m from forests. Open oak, dominated by scrub oaks and open sandy areas, had the highest use and nest success among habitats. Open oak occurred as narrow patches ( <20 m wide) in landscapes dominated by matrix habitat (palmetto‐lyonia and swale marshes). Most wide patches (>50 m) of open oak were potential population sources, where reproduction exceeded mortality. Areas with patches of open oak of less than 1 ha were usually population sinks. Open oak occurred as less flammable patches in a landscape subject to frequent fires. Population sources varied temporally and spatially with fires and site potential to support scrub oaks (soils). Analyses of landscape patterns and dynamics indicated that habitat mapping should not only include patches of currently optimal habitat but should also include landscapes associated with open oak. The influences of landscape patterns on habitat use, reproductive success, survival, and territory size can be quantified at different scales starting with attributes associated with habitat patches, nest sites, and territories. Potential mapping errors occur, however, when habitats are used to quantify the areal extent of sources and sinks and similar population attributes important for species persistence.
Reserve Coverage and Requirements in Relation to Partitioning and Generalization of Land Classes: Analyses for Western New South Wales
Authors: Pressey R.L. , Logan V.S.
Published: March 2003

The extent to which existing conservation reserves cover or represent the different land classes in a region depends on the scale at which those land classes are defined. In a previous review of regional studies we could not separate the influence on reserve coverage from aspects of scale of classification or mapping. In this study we measured the influence of three aspects of scale on the coverage of existing reserves and the area of new reserves required to represent all land classes. The aspects of scale we used were agglomerative (bottom‐up) partitioning, divisive (top‐down) partitioning, and generalization of the polygons representing discrete map units. The analyses were based on two existing classifications of a large region. One of these was originally produced at two scales of divisive partitioning. We modified the second classification to produce wide differences in the two other aspects of scale. For all aspects of scale the results confirm that existing reserves in the region tend to represent more coarse‐ than fine‐scale classes, but this depends on the criteria used to determine when classes are “represented.” For all aspects of scale, larger total areas of new reserves are needed to represent fine‐scale rather than coarse‐scale land classes. This trend holds regardless of the minimum proportional area of each land class to be represented but varies with the size of the sites considered reserves. The results reinforce the scale‐dependence of assessments of reserve coverage and establish the scale‐dependence of assessments of reserve requirements. They also indicate that comparisons of coverage and requirements between regions or in the same region through time must be standardized for type and scale of classification.
Economics, Objectives, and Success of Private Nature Reserves in Sub‐Saharan Africa and Latin America
Authors: Langholz Jeff
Published: March 2003

Current efforts for habitat protection, based largely on government efforts to establish protected areas, are not keeping pace with biodiversity loss. The conservation community must explore means for in situ protection that supplement existing government efforts. One possibility is the privately owned nature reserve. In this descriptive study a written survey of privately owned nature reserves in Sub‐Saharan Africa and Latin America was undertaken to identify their economic attributes, initial objectives, and factors necessary for attaining those objectives. Data from 32 managers of private reserves revealed that reserves can be a profitable venture. Over half were realizing a profit, and profitability among reserves had risen 21% since 1989. Despite this economic success, they proved to be motivated more by conservation goals than by personal or economic objectives. Overall the respondents ranked management factors more important than geographic, social/political, financial, or stochastic factors for accomplishing reserves’ objectives. The presence of “interesting ecological attractions” was rated the single most important factor and those factors relating to government involvement were considered least important. The results show private reserves to be an important albeit little‐known example of private‐sector involvement in conservation. The results also provide a useful analysis for those interested in private reserves, those currently operating them, and those wishing to establish them.