Conservation Genetics of the Endangered Isle Royale Gray Wolf

Abstract. The small group of wolves on Isle Royale has been studied for over three decades as a model of the relationship between large carnivores and their prey. During the last ten years the population declined from 50 individuals to as few as 12 individuals. The causes of this decline may be food shortages, disease, or reduced genetic variability. We address the issues of genetic variability and relationships of Isle Royale wolves using allozyme electrophoresis, mtDNA restriction-site analysis, and multilocus hypervariable minisatellite DNA analysis (genetic fingerprinting). Our results indicate that approximately 50% of the allozyme heterozygosity has been lost in the island population, a decline similar to that expected if no immigration had occurred from the mainland. The genetic fingerprinting data indicate that the seven sampled Isle Royale wolves are as similar as captive populations of siblings. Surprisingly, the Isle Royale wolves have an mDNA genotype that is very rare on the mainland, being found in only one of 144 mainland wolves ThFF suggests that the remaining Isle Royale wolves areprobably derived from a single female founder     

垃圾堆填区渗出液对干旱季节树苗生长的影响

本试验于１９９４年７月至１月在香港望后石垃圾堆填区进行,研究了垃圾堆填区渗出液浇灌对几种亚热带树种生长及其生理学过程的影响．结果表明,在高温低湿、植物遭受水分亏缺的条件下,应用适当浓度的垃圾堆填区渗出液浇灌同水灌和肥水灌溉类似,可显著地提高树苗的移栽成活率,促进树苗的生长,尤其对耐干旱能力低的树种,其效果更为显著．与对照相比,用适当浓度的渗出液或水浇灌显著地改善植株的水分关系,降低叶片的脱落酸（ＡＢＡ）含量,促进气孔的开放．另外,处理植株叶片的光合特性也得到了不同程度的改善．根据以上结果,作者认为,在干旱季节植物遭受严重水分亏缺的条件下,应用适当浓度的垃圾堆填区渗出液浇灌可显著地缓解干旱对树苗生长的影响,为综合治理垃圾堆填区渗出液提供了一条经济、实用和可行的途径．     

Water Resource Adequacy: Illusion and Reality

This paper examines recent shifts in technical thinking which have altered prevailing views on how to assess the adequacy of fresh water supplies to satisfy future demand. From a study of recent national and international documents at least six concepts of water resources and its uses can be shown to be undergoing significant change. They are related to: constraints on drinking water adequacy; the alternatives to increasing physical supply; the relationship of population growth to industrial and agricultural water use; the meaning of flood and drought disasters; the risks to aquatic ecosystems; and the implications of possible climatic changes. The emphasis in assessment has in turn shifted from an estimation of total supply and withdrawal towards an estimation of the effects on water quality and distribution resulting from changes in water and land use. The author shows that assessments of future supplies will have to take into account not only the total volume of water as related to growing demand but also an examination of the social and political conditions within which fundamental choices as to technologies and water management strategies will take place. Cet article étudie les récents changements dans le mode de pensée technique qui ont modifié les vues établies sur la manière d'évaluer la qualité des approvisionnements en eau douce en vue de répondre à la demande future. Partant de l'étude de documents nationaux et internationaux, il ressort au moins six concepts en matière de ressources en eau et l'on peut démontrer que ses utilisations subissent actuellement de profonds changements. Ces concepts ont trait à des contraintes concernant la qualité de l'eau potable, les différents moyens d'augmenter l'approvisionnement, la relation entre la croissance démographique et l'utilisation de l'eau à des fins industrielles et agriculturales; la signification des désastres causés par les inondations et la sécheresse, les risques qu'encourent les écosystèmes aquatiques et les implications de changements climatiques éventuels. A son tour, l'emphase dans l'évaluation est passée d'une estimation de l'approvisionnement total et du soutirage à une estimation des effets sur la qualité et les réseaux d'approvisionnement de l'eau résultant de changements dans l'utilisation de l'eau et des sols. L'auteur démontre que les évaluations des approvisionnements futurs tiendront compte non seulement du volume total de l'eau par rapport à la demande croissante mais aussi d'un examen des conditions sociales et politiques dans lesquelles se feront des choix fondamentaux en ce qui concerne les technologies et les stratégies de gestion des ressources en eau. Este artículo examina los cambios recientes que alteran el enfoque técnico de cómo evaluar la suficiencia del suministro de agua dulce para satisfacer la demands futura. Del estudio de documentos recientes, nacionales e internacionales, se puede notar que por lo menos seis conceptos sobre recursos de agua y su uso están cambiando en forma significativa. Ellos son: restricciones sobre suficiencia de agua potable; alternativas al aumento quantitativo del suministro; la relación del crecimiento de población al uso de agua en la industria y la agricultura; el significado de desastres de inundación y sequía; los riesgos del ecosistema acuático; y los efectos sobre posibles cambios climáticos. El énfasis en la evaluación a cambiado de la estimación del suministro y uso total hacia la estimación de los aspectos de la calidad de agua y su distribución resultantes de los cambios en el uso de agua y tierras. El autor muestra que la evaluación del suministro futuro tomará en cuenta no solamente el volumen total de agua en relación a la demanda creciente, sino también el examen de las condiciones sociales y políticas que influyen las decisiones fundamentales sobre la selección de technologías y la estrategia de la administración de recursos de agua.     

A Meta‐Analytic Review of Corridor Effectiveness

Abstract: Using corridors for conservation is increasing despite a lack of consensus on their efficacy. Specifically, whether corridors increase movement of plants and animals between habitat fragments has been addressed on a case‐by‐case basis with mixed results. Because of the growing number of well‐designed experiments that have addressed this question, we conducted a meta‐analysis to determine whether corridors increase movement; whether corridor effectiveness differs among taxa; how recent changes in experimental design have influenced findings; and whether corridor effectiveness differs between manipulative and natural experiments. To conduct our meta‐analysis, we analyzed 78 experiments from 35 studies using a conservative hierarchical Bayesian model that accounts for hierarchical and sampling dependence. We found a highly significant result that corridors increase movement between habitat patches by approximately 50% compared to patches that are not connected with corridors. We found that corridors were more important for the movement of invertebrates, nonavian vertebrates, and plants than they were for birds. Recent methodological advances in corridor experiments, such as controlling for the area added by corridors, did not influence whether corridors increased movement, whereas controlling for the distance between source and connected or unconnected recipient patches decreased movement through corridors. After controlling for taxa differences and whether studies controlled for distance in experimental design, we found that natural corridors (those existing in landscapes prior to the study) showed more movement than manipulated corridors (those created and maintained for the study). Our results suggest that existing corridors increase species movement in fragmented landscapes and that efforts spent on maintaining and creating corridors are worthwhile.     

Two‐Stage Recovery of Amphibian Assemblages Following Selective Logging of Tropical Forests

There is a lack of quantitative information on the effectiveness of selective‐logging practices in ameliorating effects of logging on faunal communities. We conducted a large‐scale replicated field study in 3 selectively logged moist semideciduous forests in West Africa at varying times after timber extraction to assess post logging effects on amphibian assemblages. Specifically, we assessed whether the diversity, abundance, and assemblage composition of amphibians changed over time for forest‐dependent species and those tolerant of forest disturbance. In 2009, we sampled amphibians in 3 forests (total of 48 study plots, each 2 ha) in southwestern Ghana. In each forest, we established plots in undisturbed forest, recently logged forest, and forest logged 10 and 20 years previously. Logging intensity was constant across sites with 3 trees/ha removed. Recently logged forests supported substantially more species than unlogged forests. This was due to an influx of disturbance‐tolerant species after logging. Simultaneously Simpson's index decreased, with increased in dominance of a few species. As time since logging increased richness of disturbance‐tolerant species decreased until 10 years after logging when their composition was indistinguishable from unlogged forests. Simpson's index increased with time since logging and was indistinguishable from unlogged forest 20 years after logging. Forest specialists decreased after logging and recovered slowly. However, after 20 years amphibian assemblages had returned to a state indistinguishable from that of undisturbed forest in both abundance and composition. These results demonstrate that even with low‐intensity logging (≤3 trees/ha) a minimum 20‐year rotation of logging is required for effective conservation of amphibian assemblages in moist semideciduous forests. Furthermore, remnant patches of intact forests retained in the landscape and the presence of permanent brooks may aid in the effective recovery of amphibian assemblages. Recuperación de Ensambles de Anfibios en Dos Etapas Después de la Tala Selectiva de Bosques Tropicales     

Gastrointestinal Bacterial Transmission among Humans,Mountain Gorillas,and Livestock in Bwindi Impenetrable National Park,Uganda

Abstract: Habitat overlap can increase the risks of anthroponotic and zoonotic pathogen transmission between humans, livestock, and wild apes. We collected Escherichia coli bacteria from humans, livestock, and mountain gorillas (Gorilla gorilla beringei) in Bwindi Impenetrable National Park, Uganda, from May to August 2005 to examine whether habitat overlap influences rates and patterns of pathogen transmission between humans and apes and whether livestock might facilitate transmission. We genotyped 496 E. coli isolates with repetitive extragenic palindromic polymerase chain reaction fingerprinting and measured susceptibility to 11 antibiotics with the disc‐diffusion method. We conducted population genetic analyses to examine genetic differences among populations of bacteria from different hosts and locations. Gorilla populations that overlapped in their use of habitat at high rates with people and livestock harbored E. coli that were genetically similar to E. coli from those people and livestock, whereas E. coli from gorillas that did not overlap in their use of habitats with people and livestock were more distantly related to human or livestock bacteria. Thirty‐five percent of isolates from humans, 27% of isolates from livestock, and 17% of isolates from gorillas were clinically resistant to at least one antibiotic used by local people, and the proportion of individual gorillas harboring resistant isolates declined across populations in proportion to decreasing degrees of habitat overlap with humans. These patterns of genetic similarity and antibiotic resistance among E. coli from populations of apes, humans, and livestock indicate that habitat overlap between species affects the dynamics of gastrointestinal bacterial transmission, perhaps through domestic animal intermediates and the physical environment. Limiting such transmission would benefit human and domestic animal health and ape conservation.