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Buffer Zones (buffer + zone)
Selected AbstractsEffects of Habitat Disturbance on Stream Salamanders: Implications for Buffer Zones and Watershed ManagementCONSERVATION BIOLOGY, Issue 3 2003John D. Willson To minimize the impacts of development on aquatic habitats, numerous conservation measures have been implemented, including the use of riparian buffer zones along streams and rivers. We examined the effectiveness of current buffer-zone systems for management of small watersheds in conserving stream-dwelling salamander populations in 10 small streams ( draining <40.5 ha ) in the western Piedmont of North Carolina. We captured salamanders by means of funnel traps and systematic dipnetting and used a geographic information system to calculate the percentage of disturbed habitat within the watershed of each stream and within 10.7-, 30.5-, and 61.0 -m buffer zones around each stream, upstream from our sampling locations. Although the relative abundance of salamanders was strongly inversely proportional to the percentage of disturbed habitat in the entire watersheds ( R2 = 0.71 for Desmognathus fuscus and 0.48 for Eurycea cirrigera ), we found little to no correlation between the relative abundance of salamanders and the percentage of disturbed habitat present within buffer zones ( R2 = 0.06,0.27 for D. fuscus and 0.01,0.07 for E. cirrigera ). Thus, conservation efforts aimed at preserving salamander populations in headwater streams must consider land use throughout entire watersheds, rather than just preserving small riparian buffer zones. Resumen: La destrucción y degradación del hábitat se encuentra entre la mayores amenazas a la vida silvestre, junto con el aumento global de la población humana. Para minimizar los impactos del desarrollo sobre hábitats acuáticos, se han instrumentado numerosas medidas de conservación, incluyendo el uso de zonas de amortiguamiento riparias a lo largo de arroyos y ríos. Examinamos la efectividad de los actuales sistemas de zonas de amortiguamiento usados en el manejo de cuencas pequeñas para la conservación de poblaciones de salamandras de arroyo en 10 arroyos pequeños ( que drenan <40.5 ha ) al pie de monte del occidente de Carolina del Norte. Capturamos salamandras con trampas de embudo y mediante el uso sistemático de redes y utilizamos un sistema de información geográfica para calcular el porcentaje de hábitat perturbado dentro de la cuenca de cada arroyo y dentro de zonas de amortiguamiento de 10.7-, 30.5- y 61.0-m alrededor de cada arroyo, río arriba de nuestros sitios de muestreo. Aunque los valores de abundancia relativa de salamandras fueron inversamente proporcionales al porcentaje de hábitat perturbado en el total de las cuencas ( R2 = 0.71 para Desmognathus fuscus y 0.48 para Eurycea cirrigera ), encontramos una correlación débil o inexistente entre las abundancias relativas de salamandras y el porcentaje de hábitat perturbado en las zonas de amortiguamiento R2 = 0.06,0.27 para D. fuscus y 0.01,0.07 para E. cirrigera ). Por lo tanto, los esfuerzos de conservación dirigidos a preservar poblaciones de salamandras de arroyos de cabecera deben tomar en cuenta el uso de la tierra en la superficie entera de las cuencas, en lugar de preservar pequeñas zonas de amortiguamiento riparias. [source] Environmental Narratives on Protection and Production: Nature-based Conflicts in R7iacute;o San Juan, NicaraguaDEVELOPMENT AND CHANGE, Issue 4 2000Anja Nygren This article focuses on local processes and global forces in the struggle over the fate of forests and over the contested claims of protection and production in a protected area buffer zone of Río San Juan, Nicaragua. The struggle over control of local natural resources is seen as a multifaceted process of development and power involving diverse social actors, from agrarian politicians and development agents to a heterogeneous group of local settlers, absentee cattle raisers, timber dealers, transnational corporations, and non-governmental organizations. The initial interest is in the local resource-related discourses and actions; the analysis then broadens to include the larger political-economic processes and environment-development discourses that affect the local systems of production and systems of signification. The article underlines environmental resource conflicts as one of the major challenges in subjecting structures of social power to critical analysis. [source] Large-volume sample stacking combined with separation by 2-hydroxypropyl-,-cyclodextrin for analysis of isoxyzolylpenicillins by capillary electrophoresisELECTROPHORESIS, Issue 17 2003Zhiwei Zhu Abstract A simple, quick and sensitive capillary electrophoretic technique has been developed for the pharmaceutical analysis of isoxazolylpenicillins (oxacillin, cloxacillin and dicloxacillin) at trace levels for the first time. This method comprises large-volume sample stacking using the electroosmotic flow (EOF) pump (LVSEP), separation using 2-hydroxypropyl-,-cyclodextrin (HP-,-CD) as selective complex-forming background electrolyte additive, and direct UV detection. A complete resolution was achieved in the optimal background electrolyte containing 5.2 mM HP-,-CD. LVSEP was successfully applied in their determinations to improve the sensitivity, where the EOF in the buffer zone was suppressed by using an acidic buffer with pH 3.6. The detection limits of the current technique were found to be 2.0 ,g/L for each of the isoxazolylpenicillins based on the signal-to-noise ratio of 3. The curves of peak response versus concentration were linear from 5.0 to 400.0 ,g/L with regression coefficients of 0.9982, 0.9986 and 0.9976, respectively. The interaction of isoxazolylpenicillins with HP-,-CD was discussed. The association constants for complexes of HP-,-CD with isoxazolylpenicillins were determined by electrophoretic method. The obtained association constants were 27.3, 34.9, and 48.5 M,1, respectively, being proportional to their hydrophobic properties and steric hindrances. A simple and easy-manipulative sample preparation method was developed and validated by analyzing commercially available milk samples. It was found that with current sample preparation process and instrumentation system, 0.1 mL of milk sample is enough for the analysis of isoxazolylpenicillins to meet European Union (EU) guideline of 30 ,g/kg. [source] Women's traditional fishery and alternative aquatic resource livelihood strategies in the Southern Cameroonian RainforestFISHERIES MANAGEMENT & ECOLOGY, Issue 3 2010R. E. BRUMMETT Abstract, To inform the development of alternative livelihoods, the women's traditional alok fishery in the Campo-Ma'an National Park and buffer zone of southern Cameroon were studied over 15 months. Participatory rural appraisal was used to characterise livelihood strategies among 45 households. Thirty-three cultured crops, nine farmed animal species and 65 non-timber forest products, including 31 bushmeat species are cultivated in, or harvested from, the forest. Transport is a major impediment to commercial trade of all local products. In 16 alok fishing events, average weight of fish harvested was 5.14 kg per 280 m of stream distributed among an average of 23 fishers for a return of 220 g person,1 or 40 g fish h,1 over 5 h of work. Fish and crustacean standing stock was 25 g per linear metre or 167 t when extrapolated to the zone. Implications for rainforest livelihoods in light of the Millennium Development Goals are discussed. [source] On the Cypriot States of ExceptionINTERNATIONAL POLITICAL SOCIOLOGY, Issue 2 2008Costas M. Constantinou This article explores the politics of exceptionality in Cyprus. It focuses on the postcolonial constriction of Cypriot statehood,the framing of the sovereign itself as an exception,and how the emerging discourse of exceptionality unfolded a spiral of states of exception on the ground. Looking in and across a variety of Cypriot sites and regimes (north, south, sovereign base areas and buffer zone) the article examines what claims of exceptionality legitimate in political and everyday life as well as their ironic and paradoxical effects. Finally, it looks at how the Cyprus case informs debates on current theorizations of exceptionalism. [source] Recovery of anuran community diversity following habitat replacementJOURNAL OF APPLIED ECOLOGY, Issue 1 2010David Lesbarrères Summary 1.,Recently habitat degradation, road construction and traffic have all increased with human populations, to the detriment of aquatic habitats and species. While numerous restoration programmes have been carried out, there is an urgent need to follow their success to better understand and compensate for the decline of amphibian populations. To this end, we followed the colonization success of an anuran community across multiple replacement ponds created to mitigate large-scale habitat disturbance. 2.,Following construction of a highway in western France, a restoration project was initiated in 1999 and the success of restoration efforts was monitored. The amphibian communities of eight ponds were surveyed before they were destroyed. Replacement ponds were created according to precise edaphic criteria, consistent with the old pond characteristics and taking into account the amphibian species present in each. The presence of amphibian species was recorded every year during the breeding period for 4 years following pond creation. 3.,Species richness initially declined following construction of the replacement ponds but generally returned to pre-construction levels. Species diversity followed the same pattern but took longer to reach the level of diversity recorded before construction. Pond surface area, depth and sun exposure were the most significant habitat characteristics explaining both amphibian species richness and diversity. Similarly, an increase in the number of vegetation strata was positively related to anuran species richness, indicating the need to maintain a heterogeneous landscape containing relatively large open wetland areas. 4.,Synthesis and applications. We highlight the species-specific dynamics of the colonization process, including an increase in the number of replacement ponds inhabited over time by some species and, in some cases, an increase in population size. Our work suggests that successful replacement ponds can be designed around simple habitat features, providing clear benefits for a range of amphibian species, which will have positive cascading effects on local biodiversity. However, consideration must also be given to the terrestrial buffer zone when management strategies are being planned. Finally, our study offers insight into the successful establishment of anuran communities over a relatively short time in restored or replacement aquatic environments. [source] Sharing natural resources: mountain gorillas and people in the Parc National des Volcans, RwandaAFRICAN JOURNAL OF ECOLOGY, Issue 3 2010Hein Van Gils Abstract The compatibility of natural resource use by people and mountain gorillas (Gorilla beringei beringei) within the Parc National des Volcans was studied. The distribution of gorillas was modelled using a Maximum Entropy algorithm. Biophysical predictor variables were trained with daily GPS locations of gorillas during 2006. Elevation, as a climate surrogate, was the best predictor (58%) of the occurrence of gorillas. The mid-altitudes (2500,3500 m a.s.l.) contained the bulk of the gorilla groups. Incoming solar radiation, as proxy for comfortable nesting sites, was the second best predictor (17%). Vegetation types, as foliage provider, (13%) and slope steepness for providing security (12%) were contributing predictors. The modelled and actual gorilla distributions were together overlaid with people's resource use in the park. Both people and gorillas were congregated in the areas identified as most suitable for gorillas. However, within these areas spatial segregation was found between human natural resource-users and gorillas. Therefore, the number of gorillas is likely to be limited by the human natural resource use within the park. A perimeter fence, the introduction of community-based natural resource management, and a buffer zone are discussed as short-, medium- and long-term mitigation measures. Résumé Nous avons étudié la compatibilité entre l'utilisation des ressources naturelles par les hommes et la présence des gorilles de montagnes (Gorilla beringei beringei) dans le Parc National des Volcans. La distribution des gorilles fut modélisée en utilisant un algorithme d'entropie maximum. En 2006, on a testé des variables de prédicteurs biophysiques, avec localisation quotidienne des gorilles par GPS. L'altitude, substitut du climat, était le meilleur prédicteur (58%) de la présence de gorilles. La plupart des groupes de gorilles se trouvaient à des altitudes moyennes (2 500,3 000 m). Le rayonnement solaire, condition de sites de nidification confortables, étaient le deuxième prédicteur (17%). Les types de végétation, fournisseurs de feuilles (13%) et l'importance des pentes, gage de sécurité (12%) étaient des prédicteurs contributeurs. Les distributions modélisées et réelles des gorilles furent superposées à l'utilisation des ressources du parc par les gens. Les hommes et les gorilles étaient rassemblés dans les zones identifiées comme les plus favorables pour les gorilles. Cependant, dans ces zones, on a trouvé une ségrégation spatiale entre les utilisateurs humains des ressources naturelles et les gorilles. Le nombre de gorilles risque donc d'être limité par l'utilisation humaine des ressources naturelles dans le parc. L'on discute de la pose d'une clôture en périphérie, de l'introduction d'une gestion communautaire des ressources naturelles et de la définition d'une zone tampon comme mesures de mitigation à court, moyen et long terme. [source] Pattern and sustainability of the bushmeat trade in the Haut Niger National Park, Republic of GuineaAFRICAN JOURNAL OF ECOLOGY, Issue 4 2009David Brugiere Abstract To document the bushmeat trade in the buffer zone of the Haut Niger National Park (HNNP), Republic of Guinea, we monitored the number of carcasses offered for sale in 16 villages over a one year period in 2001. Overall, we counted a total of 9134 carcasses from 27 species. This represents a biomass harvest of about 170,000 kg, a figure that could reach 335,100 kg when game consumed by hunters (i.e. not sold) and markets not sampled are taken into account. Ungulates (eleven species) and rodents (four species) accounted for 53.5% and 24.8% of the carcasses counted respectively (80.8% and 11.4% of the total biomass, respectively). The number of carcasses counted in villages bordering a heavily trafficked road was significantly higher than in more rural villages, thus highlighting the stimulating effect of roads on the bushmeat trade. Compared with existing data collected in 1995, the proportion of ungulates counted in the Mansira Moribaya village in 2001 increased significantly while that of rodents decreased significantly. The harvest of duiker species at Mansira Moribaya was in excess of the maximum sustainable harvest. These results of this study were used to establish a sustainable wildlife management scheme in the HNNP. Résumé Pour documenter le commerce de viande de brousse dans la zone tampon du Parc National du Haut Niger, en République de Guinée, nous avons contrôlé le nombre de carcasses proposées à la vente pendant une année (2001) dans 16 villages. En tout, nous avons compté 9 134 carcasses appartenant à 27 espèces. Cela représente un prélèvement de biomasse d'environ 170.000 kg, un chiffre qui pourrait même atteindre 335.100 kg si l'on tient compte de la viande consommée par les chasseurs (c.-à-d. pas vendue) et des marchés qui n'ont pas été repris dans notre échantillon. Les ongulés (11 espèces) et les rongeurs (quatre espèces) représentaient 53,5% et 24,8% des carcasses comptées et comptaient respectivement pour 80,8% et 11,4% de la biomasse totale. Le nombre de carcasses comptées dans les villages longeant une route très fréquentée était significativement plus élevé que dans des villages plus ruraux, ce qui met en évidence l'effet dynamisant des routes sur le commerce de viande de brousse. Comparée aux données existantes récoltées en 1995, la proportion d'ongulés comptés dans le village de Mansira Moribaya en 2001 a augmenté significativement alors que celui des rongeurs a diminué significativement. Le prélèvement des espèces de céphalophes à Mansira Moribaya dépassait le prélèvement maximum soutenable. Les résultats de cette étude ont servi àétablir un programme de gestion durable de la faune sauvage dans le Parc National du Haut Niger. [source] Spatial variation of soil test phosphorus in a long-term grazed experimental grassland fieldWeijun Fu1, 2JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2010Hubert Tunney Abstract The spatial variation of soil test P (STP) in grassland soils is becoming important because of the use of STP as a basis for policies such as the recently EU-introduced Nitrate Directive. This research investigates the spatial variation of soil P in grazed grassland plots with a long-term (38 y) experiment. A total of 326 soil samples (including 14 samples from an adjacent grass-wood buffer zone) were collected based on a 10 × 10 m2 grid system. The samples were measured for STP and other nutrients. The results were analyzed using conventional statistics, geostatistics, and a geographic information system (GIS). Soil test P concentrations followed a lognormal distribution, with a median of 5.30 mg L,1 and a geometric mean of 5.35 mg L,1. Statistically significant (p < 0.01) positive correlation between STP and pH was found. Spatial clusters and spatial outliers were detected using the local Moran's I index (a local indicator of spatial association) and were mapped using GIS. An obvious low-value spatial-cluster area was observed on the plots that received zero-P fertilizer application from 1968 to 1998 and a large high-value spatial-cluster area was found on the relatively high-P fertilizer application plots (15,kg ha,1 y,1). The local Moran's I index was also effective in detecting spatial outliers, especially at locations close to spatial-cluster areas. To obtain a reliable and stable spatial structure, semivariogram of soil-P data was produced after elimination of spatial outliers. A spherical model with a nugget effect was chosen to fit the experimental semivariogram. The spatial-distribution map of soil P was produced using the kriging interpolation method. The interpolated distribution map was dominated by medium STP values, ranging from 3 mg to 8 mg L,1. An evidently low-P-value area was present in the upper side of the study area, as zero or short-term P fertilizer was applied on the plots. Meanwhile, high-P-value area was located mainly on the plots receiving 15,kg P ha,1 y,1 (for 38 y) as these plots accumulated excess P after a long-term P-fertilizer spreading. The high- or low-value patterns were in line with the spatial clusters. Geostatistics, combined with GIS and the local spatial autocorrelation index, provides a useful tool for analyzing the spatial variation in soil nutrients. [source] Stream Condition in Piedmont Streams with Restored Riparian Buffers in the Chesapeake Bay Watershed,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2010Leslie L. Orzetti Orzetti, Leslie L., R. Christian Jones, and Robert F. Murphy, 2010. Stream Condition in Piedmont Streams with Restored Riparian Buffers in the Chesapeake Bay Watershed. Journal of the American Water Resources Association (JAWRA) 46(3):473-485. DOI: 10.1111/j.1752-1688.2009.00414.x Abstract:, This study tested the efficacy of restored forest riparian buffers along streams in the Chesapeake Bay watershed by examining habitat, selected water quality variables, and benthic macroinvertebrate community metrics in 30 streams with buffers ranging from zero to greater than 50 years of age. To assess water quality we measured in situ parameters (temperature, dissolved oxygen, and conductivity) and laboratory-analyzed grab samples (soluble reactive phosphorus, total phosphorus, nitrate, ammonium, and total suspended solids). Habitat conditions were scored using the Environmental Protection Agency Rapid Bioassessment Protocols for high gradient streams. Benthic macroinvertebrates were quantified using pooled riffle/run kick samples. Results showed that habitat, water quality, and benthic macroinvertebrate metrics generally improved with age of restored buffer. Habitat scores appeared to stabilize between 10 and 15 years of age and were driven mostly by epifaunal substrate availability, sinuosity, embeddedness, and velocity depth regime. Benthic invertebrate taxa richness, percent Ephemeroptera, Plecoptera, Trichoptera minus hydropsychids (%EPT minus H), % Ephemeroptera, and the Family Biotic Index were among the metrics which improved with age of buffer zone. Results are consistent with the hypothesis that forest riparian buffers enhance instream habitat, water quality, and resulting benthic macroinvertebrate communities with noticeable improvements occurring within 5-10 years postrestoration, leading to conditions approaching those of long established buffers within 10-15 years of restoration. [source] Land-use and cover changes (1988,2002) around budongo forest reserve, NW Uganda: implications for forest and woodland sustainabilityLAND DEGRADATION AND DEVELOPMENT, Issue 6 2008E. N. Mwavu Abstract Land-use and cover changes around Budongo Forest Reserve (BFR) were analysed from multi-temporal LandSat images (1988 and 2002) and associated field-based studies in 2003,2004. Three major land-use and cover classes: forest/woodland, sugarcane plantations and grassland/shifting-cultivation/settlements were clearly discriminated. The area under sugarcane cultivation increased over 17-fold, from 690,ha in 1988 to 12729,ha in 2002, with a concomitant loss of about 4680,ha (8·2 per cent) of forest/woodland, mainly on the southern boundary of BFR. Land-use and cover changes were a result of (a) agricultural expansion, (b) increasing human population, exacerbated by large influxes of refugees, (c) conflicts of interest and political interference in the management of BFR and (d) unclear land tenure. Agriculture is the main land-use practice and source of income to local people, with commercial sugarcane and tobacco as the primary cash crops. Individual smallholder sugarcane plantations covered distances ranging from 30 to 1440,m along the BFR edge, with no buffer zone, resulting in direct conflicts between farmers and forest wild animals. There is an ever-increasing need for more land for agricultural expansion, resulting in continued loss of forest/woodland on private/communal lands and encroachment into BFR. This unsustainable agricultural expansion and the local people's perception of BFR as an obstacle to agriculture, threatens the conservation of its threatened wild plants (e.g. Raphia farinifera) and the endangered chimpanzees. Therefore, their sustainable management for both development and conservation will require strong and incorruptible institutions that will seek a balance between resource exploitation and conservation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Long-term impacts of an organophosphate-based regime of pesticides on field and field-edge Collembola communitiesPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2002Geoff K Frampton Abstract During a 6-year study, effects of two contrasting regimes of pesticide use on pitfall and suction catches of Collembola were monitored in an arable field under a rotation of grass and winter wheat. Current farm practice (CFP) represented conventional fungicide and herbicide use plus applications of organophosphorus (OP) insecticides, whereas reduced input approach (RIA) utilised minimum inputs of fungicides and herbicides and excluded any use of insecticides. Compared with RIA, the CFP regime caused a substantial decline in the abundance and diversity of Collembola in the field, including the local disappearance of one species, without recovery during the study. At the field edge, which was protected during OP applications by a 6-m unsprayed buffer zone, effects of the CFP regime were less severe, and were not persistent in the long term. Some Collembola species occurred only in field-edge samples. Pitfall and suction sampling yielded remarkably similar patterns of catches, indicating that pitfall trapping may be appropriate for detecting long-term changes in collembolan abundance caused by intensive agricultural management practices. © 2002 Society of Chemical Industry [source] Aerobic Heterotrophic Bacterial and Fungal Communities in the Topsoil of Omo Biosphere Reserve in Southwestern Nigeria,BIOTROPICA, Issue 2 2000A. I. Okoh ABSTRACT As a part of the surveillance effort to monitor the ecological status of Omo Biosphere Reserve in the southwestern region of Nigeria, the aerobic heterotrophic bacterial and fungal communities of the topsoil were investigated in March 1995 and April 1996, before the onset of the rainy season. Four distinct wood-tree plantations, a core strict nature reserve (SNR) area, and a buffer zone were sampled. The topsoil samples (7.5 cm depth), including the litter, were taken with an auger (8 cm diameter) and transported to the laboratory in polyethylene bags. One-gram dry weight equivalent of sample was suspended in 10 ml sterile water, and serial dilutions from it were used for the estimation of bacterial and fungal densities. The bacterial and fungal densities ranged in the order of 106 and 103 cfu/g, respectively. Out of the 18 bacterial and 16 fungal species that were obtained, 13 and 12, respectively, were isolated from the core SNR. About 46 to 69 percent of the bacteria and 50 to 83 percent of the fungi species found in the SNR were absent in different combinations in the plantations and the buffer zone; these variations were significant among the sites monitored. The bacterial and fungal species compositions were significantly different between the SNR and each of the other sites. Proportional distributions within the sites were significant only for the bacterial communities. It would appear that plantation and human activities have caused significant changes in the distribution and species richness of the heterotrophic bacterial and fungal communities relative to the undisturbed SNR area of the Omo Biosphere Reserve. [source] Landscape Clubs: Co-existence of Genetically Modified and Organic CropsCANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 2 2007W. H. Furtan The possibility of increased production of genetically modified (GM) crops in agriculture accentuates the need to examine the feasibility of GM and non-GM technologies co-existing on a common physical landscape. Using the theory of clubs, this paper examines the possibility of co-existence for GM and organic wheat technologies through the formation of an organic club with an endogenously determined buffer zone. Given the available data on prices, and yields, it is shown that a club can be created in which GM and organic agricultural production technologies can economically co-exist in the same physical landscape. Specifically, co-existence results in an increase in economic welfare over a situation where only GM technology is used but is not Pareto superior because producers in the buffer zone will incur injury. We show that organic producers in the club can compensate producers in the buffer zone and still be better off. Hence, the compensation principle holds. La possibilité de production accrue de cultures génétiquement modifiées (GM) accentue la nécessité d'examiner la faisabilité de coexistence des technologies GM et non GM dans un même paysage agricole. À l'aide de la théorie des clubs, le présent article a examiné la possibilité de coexistence des technologies de culture de blé GM et de blé biologique en créant un club ,biologique, comprenant une zone tampon déterminée de façon endogène. Compte tenu des données disponibles concernant les prix et les rendements, il est montré qu'il est possible de créer un club au sein duquel les technologies de production de cultures biologiques et GM peuvent économiquement coexister dans un même paysage naturel. Spécifiquement, la coexistence engendre une augmentation du bien-être économique par rapport à une situation où seule la technologie GM est utilisée, mais elle n'est pas Pareto supérieure parce que les producteurs dans la zone tampon subiront des dommages. Nous montrons que les producteurs de cultures biologiques membres du club peuvent indemniser les producteurs de la zone tampon tout en demeurant en bonne position. Le principe de compensation tient donc. [source] Effects of Habitat Disturbance on Stream Salamanders: Implications for Buffer Zones and Watershed ManagementCONSERVATION BIOLOGY, Issue 3 2003John D. Willson To minimize the impacts of development on aquatic habitats, numerous conservation measures have been implemented, including the use of riparian buffer zones along streams and rivers. We examined the effectiveness of current buffer-zone systems for management of small watersheds in conserving stream-dwelling salamander populations in 10 small streams ( draining <40.5 ha ) in the western Piedmont of North Carolina. We captured salamanders by means of funnel traps and systematic dipnetting and used a geographic information system to calculate the percentage of disturbed habitat within the watershed of each stream and within 10.7-, 30.5-, and 61.0 -m buffer zones around each stream, upstream from our sampling locations. Although the relative abundance of salamanders was strongly inversely proportional to the percentage of disturbed habitat in the entire watersheds ( R2 = 0.71 for Desmognathus fuscus and 0.48 for Eurycea cirrigera ), we found little to no correlation between the relative abundance of salamanders and the percentage of disturbed habitat present within buffer zones ( R2 = 0.06,0.27 for D. fuscus and 0.01,0.07 for E. cirrigera ). Thus, conservation efforts aimed at preserving salamander populations in headwater streams must consider land use throughout entire watersheds, rather than just preserving small riparian buffer zones. Resumen: La destrucción y degradación del hábitat se encuentra entre la mayores amenazas a la vida silvestre, junto con el aumento global de la población humana. Para minimizar los impactos del desarrollo sobre hábitats acuáticos, se han instrumentado numerosas medidas de conservación, incluyendo el uso de zonas de amortiguamiento riparias a lo largo de arroyos y ríos. Examinamos la efectividad de los actuales sistemas de zonas de amortiguamiento usados en el manejo de cuencas pequeñas para la conservación de poblaciones de salamandras de arroyo en 10 arroyos pequeños ( que drenan <40.5 ha ) al pie de monte del occidente de Carolina del Norte. Capturamos salamandras con trampas de embudo y mediante el uso sistemático de redes y utilizamos un sistema de información geográfica para calcular el porcentaje de hábitat perturbado dentro de la cuenca de cada arroyo y dentro de zonas de amortiguamiento de 10.7-, 30.5- y 61.0-m alrededor de cada arroyo, río arriba de nuestros sitios de muestreo. Aunque los valores de abundancia relativa de salamandras fueron inversamente proporcionales al porcentaje de hábitat perturbado en el total de las cuencas ( R2 = 0.71 para Desmognathus fuscus y 0.48 para Eurycea cirrigera ), encontramos una correlación débil o inexistente entre las abundancias relativas de salamandras y el porcentaje de hábitat perturbado en las zonas de amortiguamiento R2 = 0.06,0.27 para D. fuscus y 0.01,0.07 para E. cirrigera ). Por lo tanto, los esfuerzos de conservación dirigidos a preservar poblaciones de salamandras de arroyos de cabecera deben tomar en cuenta el uso de la tierra en la superficie entera de las cuencas, en lugar de preservar pequeñas zonas de amortiguamiento riparias. [source] Vegetation and topographic controls on sediment deposition and storage on gully beds in a degraded mountain areaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2009Armando Molina Abstract Active gully systems developed on highly weathered or loose parent material are an important source of runoff and sediment production in degraded areas. However, a decrease of land pressure may lead to a return of a partial vegetation cover, whereby gully beds are preferred recolonization spots. Although the current knowledge on the role of vegetation on reducing sediment production on slopes is well developed, few studies exist on the significance of restoring sediment transport pathways on the total sediment budget of degraded mountainous catchments. This study in the Ecuadorian Andes evaluates the potential of vegetation to stabilize active gully systems by trapping and retaining eroded sediment in the gully bed, and analyses the significance of vegetation restoration in the gully bed in reducing sediment export from degraded catchments. Field measurements on 138 gully segments located in 13 ephemeral steep gullies with different ground vegetation cover indicate that gully bed vegetation is the most important factor in promoting short-term (1,15 years) sediment deposition and gully stabilization. In well-vegetated gully systems ( , 30% of ground vegetation cover), 0.035 m3 m,1 of sediment is deposited yearly in the gully bed. Almost 50 per cent of the observed variance in sediment deposition volumes can be explained by the mean ground vegetation cover of the gully bed. The presence of vegetation in gully beds gives rise to the formation of vegetated buffer zones, which enhance short-term sediment trapping even in active gully systems in mountainous environments. Vegetation buffer zones are shown to modify the connectivity of sediment fluxes, as they reduce the transport efficiency of gully systems. First calculations on data on sediment deposition patterns in our study area show that gully bed deposition in response to gully bed revegetation can represent more than 25 per cent of the volume of sediment generated within the catchment. Our findings indicate that relatively small changes in landscape connectivity have the potential to create strong (positive) feedback loops between erosion and vegetation dynamics. Copyright © 2009 John Wiley & Sons, Ltd. [source] Official survey, in 2002, for detection of Erwinia amylovora in a proposed protected zone in Jihomoravsky region (Czech Republic)1EPPO BULLETIN, Issue 3 2004O. Vahala Inspectors of the Czech NPPO surveyed the occurrence of fireblight Erwinia amylovora in an area of Jihomoravsky region (South Moravia) proposed as an EU protected zone, including 16 designated buffer zones around nurseries. The disease was not detected in communes where fireblight hosts are grown (nurseries, variety testing stations, orchards) or in buffer zones around nurseries. In 902 communes where fireblight hosts are grown only in orchards or not at all, wild host plants were inspected at 2.629 observation points (2137 located by GARMIN GPS). In Vy,kov district, suspected fireblight was confirmed at one observation point on Crataegus, growing by a railway in Rousínov commune and, in the course of a delimiting survey outside observation points, in four other communes (Drnovice, Habrovany, Komo,any and Vy,kov). [source] Principles and approaches to abate seabird by-catch in longline fisheriesFISH AND FISHERIES, Issue 1 2005Eric Gilman Abstract Mortality in longline fisheries is a critical global threat to most albatross and large petrel species. Here we identify key principles and approaches to identify and achieve broad use of effective seabird by-catch avoidance methods. Despite the availability of highly effective and cost-saving seabird avoidance methods, few longline fleets employ them. Given the political context and capacity of management authorities of the majority of longline fisheries, it is critical to identify seabird avoidance strategies that are not only highly effective, but are also economically viable and commercially practical. Adoption of an international performance standard for longline baited hook,sink rate, and prescribing minimum gear weighting designs that meet this standard that are achievable by all longline fisheries, would be an important step forward towards resolving low use of seabird avoidance methods by vessels, including those in illegal, unregulated and unreported fisheries. Due to differences between fleets, no single seabird avoidance measure is likely to be effective and practical in all longline fisheries. Therefore, testing of seabird avoidance methods in individual fleets is needed to determine efficacy and economic viability. Longline fishers should directly participate in these trials as they have a large repository of knowledge and skills to effectively develop and improve seabird by-catch avoidance techniques, and this provides industry with a sense of ownership for uptake of effective by-catch reduction methods. Establishing protected areas containing seabird colonies and adjacent waters within a nation's EEZ can be an expedient method to address seabird by-catch. However, establishing high seas marine protected areas to restrict longline fishing in seabird foraging areas, which would require extensive and dynamic boundaries and large buffer zones, may not be a viable short-term solution because of the extensive time anticipated to resolve legal complications with international treaties, to achieve international consensus and political will, and to acquire requisite extensive resources for surveillance and enforcement. Analysis of results of research on seabird avoidance methods reveals that the most reliable comparisons of the efficacy of alternative strategies are from comparing the effectiveness of methods tested in a single experiment. Benefits from standardizing the reporting of seabird by-catch rates to account for seabird abundance are described. To provide the most precise inputs for seabird population models, estimates of seabird mortality in longline fisheries should account for seabird falloff from hooks before hauling, delayed mortality of seabirds caught but freed from gear, and mortality caused by hooks discarded in offal. [source] Effects of land use on aquatic macrophyte diversity and water quality of pondsFRESHWATER BIOLOGY, Issue 4 2010MUNEMITSU AKASAKA Summary 1. Aquatic macrophyte diversity and water quality of 55 ponds in western Japan were related to land use and morphometric variables to identify the environmental factors that sustain biodiversity and the spatial extent at which these factors operate. 2. The relevant spatial extent for floating-leaved macrophyte richness (500 m from pond edge) was larger than that for submerged macrophyte occurrence (10, 75 and 100 m), whereas emergent macrophyte richness was best explained at much larger extents (1000 m). Total macrophyte richness was explained at the extent of 500, 750 and 1000 m. The extents relevant for explaining the physicochemical condition of pond water (100 and 250 m) were similar to those for submerged and floating-leaved macrophytes, suggesting that these two growth forms are more sensitive to water quality compared to emergent macrophytes. 3. Diversity of all three growth forms and that of total macrophytes collectively were inversely related to turbidity and nutrient concentration; among the three growth forms, submerged macrophytes were most affected by water quality. 4. Negative relationships were found between the proportion of urban area and the diversity of the three growth forms and that of total macrophytes and water quality. Species richness of emergent, floating-leaved and total macrophytes decreased with depth and increased with surface area up to about 5000 m2, above which it declined. 5. Urbanisation and enlargement of ponds were the two main factors that decreased aquatic macrophyte diversity in irrigation ponds. To alleviate the adverse effects of urban areas on aquatic macrophyte diversity, our results suggest that management efforts should focus on the creation of buffer zones within the relevant spatial extent from the pond edge. [source] Valuation of biodiversity effects from reduced pesticide useINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 2 2006Jesper S. Schou Abstract This study deals with the effects on biodiversity of pesticide-free buffer zones along field margins. Using choice modeling, the majority of respondents to a survey on pesticide use in the environment are willing to accept an increase in the price of bread if the survival of partridge chicks and the number of wild plants increase. The study identifies the need for further empirical work with respect to methodological validation, price estimation, and the use of survey results in policy analysis. In particular, the environmental effects of pesticide use are complex and, therefore, present difficult challenges when presenting information to lay people. Forty-one percent of respondents changed their responses regarding willingness to pay more for bread when references to pesticide use were introduced in the questionnaire. This indicates that scenarios depicting changes in pesticide use can be difficult to present to lay people in an economically rational and well-defined context. Thus, in the study of valuation related to changes in pesticide use, much attention should be devoted to the design and definition of the context. Furthermore, the effects of providing different background information, e.g., with or without the mention of pesticides, should be tested. [source] Tourism, livelihoods and protected areas: opportunities for fair-trade tourism in and around National parksINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 5 2001Harold Goodwin The development and implementation of ,alternative livelihood projects' by donor agencies and conservation organisations has become one of the most commonly-applied management prescriptions to alleviate existing or potential conflicts between protected areas and local livelihoods. The use of these projects is a common feature of so-called Integrated Conservation and Development Projects (ICDPs). In most cases, the promotion of these initiatives are undertaken as extensions of protected area programmes and often take place in buffer zones. Examples of projects that seek to improve local livelihoods in and around protected areas are common, and many of them have a tourism component. However, the results of tourism components of ICDPs have often been disappointing with local people benefiting little from tourism revenues. Nevertheless, many national parks are major tourist attractions in rural, and often marginal, areas and do offer significant opportunities for indigenous enterprise development. People living in and around these protected areas often have high expectations of what tourism could offer them. Using data collected in the south east lowveld of Zimbabwe for the DFID Tourism, Conservation and Sustainable Development project an analysis of local people's expectations of tourism is presented. The survey covered nine villages and there are significant differences in the responses. Local people were asked about their experience of tourism and their aspirations, including their preferred ways of earning money from tourism. Finally an analysis of their perceptions of the barriers to their involvement in the industry is presented. The paper then addresses the ways in which a national park or conservancy might respond to these aspirations and seek to involve local people in tourism enabling them to secure all or part of their livelihood from tourism related employment or entrepreneurial activity. An analysis of the preferences of tourists surveyed in Gonarezhou about activities, which they would wish to participate in if they were available, is presented. The paper concludes with an analysis of the opportunities for the managers of state, communal or privately owned land to create and support opportunities for local people to participate in the tourism industry and to benefit from fairly traded tourism. These strategies include marketing and business development support, regulation and price management. [source] Can oil palm plantations be made more hospitable for forest butterflies and birds?JOURNAL OF APPLIED ECOLOGY, Issue 4 2008Lian Pin Koh Summary 1Rising global demand for palm oil is likely to exacerbate deforestation rates in oil palm-producing countries. This will lead to a net reduction in biodiversity unless measures can be taken to improve the value of oil palm plantations. 2Here, I investigate whether the biodiversity of oil palm plantations can be increased by determining how forest-dwelling butterflies and birds in these plantations are affected by vegetation characteristics at the local level (e.g. epiphyte prevalence) and by natural forest cover at the landscape level (e.g. old-growth forests surrounding oil palm estates). 3Across transects, vegetation variables explained 0,1·2% of the variation in butterfly species richness and 0,7% of that in bird species richness. The most important predictors of species richness across transects were percentage ground cover of weeds for butterflies; and epiphyte prevalence and presence of leguminous crops for birds. Across estates, natural forest cover explained 1·2,12·9% of the variation in butterfly species richness and 0·6,53·3% of variation in bird species richness. The most important predictors of species richness across estates were percentage cover of old-growth forests surrounding an estate for butterflies; and percentage cover of young secondary forests surrounding an estate for birds. 4Synthesis and applications. In order to maximize biodiversity in oil palm plantations, oil palm companies and local governments should work together to preserve as much of the remaining natural forests as possible by, for example, creating forested buffer zones around oil palm estates or protecting remnant forest patches in the landscape. [source] PREDICTION OF STREAM TEMPERATURE IN FORESTED WATERSHEDS,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2004V. Sridhar ABSTRACT: Removal of streamside vegetation changes the energy balance of a stream, and hence its temperature. A common approach to mitigating the effects of logging on stream temperature is to require establishment of buffer zones along stream corridors. A simple energy balance model is described for prediction of stream temperature in forested headwater watersheds that allows evaluation of the performance of such measures. The model is designed for application to "worst case" or maximum annual stream temperature, under low flow conditions with maximum annual solar radiation and air temperature. Low flows are estimated via a regional regression equation with independent variables readily accessible from GIS databases. Testing of the energy balance model was performed using field data for mostly forested basins on both the west and east slopes of the Cascade Mountains, and was then evaluated using the regional equations for low flow and observed maximum reach temperatures in three different east slope Cascades catchments. A series of sensitivity analyses showed that increasing the buffer width beyond 30 meters did not significantly decrease stream temperatures, and that other vegetation parameters such as leaf area index, average tree height, and to a lesser extent streamside vegetation buffer width, more strongly affected maximum stream temperatures. [source] Dispersal kernels of the invasive alien western corn rootworm and the effectiveness of buffer zones in eradication programmes in EuropeANNALS OF APPLIED BIOLOGY, Issue 1 2010L.R. Carrasco Europe is attempting to contain or, in some regions, to eradicate the invading and maize destroying western corn rootworm (WCR). Eradication and containment measures include crop rotation and insecticide treatments within different types of buffer zones surrounding new introduction points. However, quantitative estimates of the relationship between the probability of adult dispersal and distance from an introduction point have not been used to determine the width of buffer zones. We address this by fitting dispersal models of the negative exponential and negative power law families in logarithmic and non-logarithmic form to recapture data from nine mark-release-recapture experiments of marked WCR adults from habitats as typically found in the vicinity of airports in southern Hungary in 2003 and 2004. After each release of 4000,6300 marked WCR, recaptures were recorded three times using non-baited yellow sticky traps at 30,305 m from the release point and sex pheromone-baited transparent sticky traps placed at 500,3500 m. Both the negative exponential and negative power law models in non-log form presented the best overall fit to the numbers of recaptured adults (1% recapture rate). The negative exponential model in log form presented the best fit to the data in the tail. The models suggested that half of the dispersing WCR adults travelling along a given bearing will have travelled between 117 and 425 m and 1% of the adults between 775 and 8250 m after 1 day. An individual-based model of dispersal and mortality over a generation of WCR adults indicated that 9.7,45.3% of the adults would escape a focus zone (where maize is only grown once in 3 consecutive years) of 1 km radius and 0.6,21% a safety zone (where maize is only grown once in 2 consecutive years) of 5 km radius and consequently current European Commission (EC) measures are inadequate for the eradication of WCR in Europe. Although buffer zones large enough to allow eradication would be economically unpalatable, an increase of the minimum width of the focus zone from 1 to 5 km and the safety zone from 5 to 50 km would improve the management of local dispersal. [source] Appraising riparian management effects on benthic macroinvertebrates in the Wye River systemAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2010Esther Clews Abstract 1.Agriculture, urbanization or forestry in river catchments can influence river organisms through diffuse effects on hydrology and hydrochemistry, or local effects on habitat character, bank erosion and sediment delivery. Riparian buffer zones are sometimes established to mitigate undesirable effects on salmonids, but consequences for organisms such as macroinvertebrates are less well known. 2.Riparian fencing and tree coppicing were carried out on upland tributaries of the Welsh River Wye (UK) from 1997 onwards with the aim of enhancing conditions for salmonid fish. The present study used routine, agency monitoring data to compare assemblages in three recently managed streams and five adjacent control streams. Data between 1995 and 2004 were used to assess treatment effects through time. 3.Post-treatment (2000,2004) assemblages were richer in recently managed streams than in controls, mostly due to apparent gains of taxa typical of channel margins and lowland, warmer conditions. However, results were equivocal because invertebrate families typical of lowland, more eutrophic conditions increased in occurrence in all reaches irrespective of treatment, while overall richness declined. 4.This study illustrates how routine monitoring data can reveal some effects of riparian land-use and management on stream biota. However, improved experimental design, ideally using a before,after control,intervention approach, would have allowed more effective assessment in this case study where confounding trends were so marked. We advocate using such approaches in future restoration studies to allow stronger inference and greater statistical power. The recent general decline in the richness of typical headwater organisms in the Wye system requires investigation. Copyright © 2010 John Wiley & Sons, Ltd. [source] Coastal wetlands of the northern Gulf of California: inventory and conservation statusAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 1 2006Edward P. Glenn Abstract 1.Above 28°N, the coastline of the northern Gulf of California is indented at frequent intervals by negative or inverse estuaries that are saltier at their backs than at their mouths due to the lack of freshwater inflow. These ,esteros' total over 215 000 ha in area and encompass mangrove marshes below 29°N and saltgrass (Distichlis palmeri) marshes north of 29°N. An additional 6000 ha of freshwater and brackish wetlands are found in the Colorado River delta where fresh water enters the intertidal zone. 2.The mangrove marshes in the Gulf of California have been afforded some degree of protected status in Mexico, but the northern saltgrass esteros do not have priority conservation status and are increasingly becoming development targets for resorts, vacation homes and aquaculture sites. 3.We conducted an inventory of the marshes using aerial photography and satellite images, and evaluated the extent and type of development on each marsh. We reviewed the available literature on the marshes to document their vegetation types and ecological functions in the adjacent marine and terrestrial ecosystems. 4.Over 95% of the mangrove marshes have been developed for shrimp farming. However, the farms are built adjacent to, rather than in, the marshes, and the mangrove stands are still mostly intact. 5.The majority of saltgrass marshes above the mangrove line are still relatively unspoiled. However, resort and vacation home development is taking place on land surrounding them. 6.We recommend a system of protected reserves incorporating the pristine wetlands, along with water quality management and buffer zones for the more developed esteros. The saltgrass marshes should be considered for conservation protection, similar to the protection given to the southern mangrove marshes whose value has already been recognized. Copyright © 2006 John Wiley & Sons, Ltd. [source] Directionality of pre- and post-breeding migrations of a marbled newt population (Triturus marmoratus): implications for buffer zone managementAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2005P. Marty Abstract 1.The marbled newt, Triturus marmoratus, is a vulnerable urodele species (listed on Annex IV of the European Habitats Directive). However, biological information about their migration and the terrestrial habitats they use is relatively scarce. In order to investigate the influence of the surrounding habitats of a local pond on the directions of pre- and post-breeding migrations, adult newts were monitored over two successive years (from February 2000 to June 2001) at a permanent pond in south-western France using a drift fence and pitfall traps. 2.In both sexes the entry and exit directions were non-randomly distributed. Furthermore, males and females generally followed similar directions facing an oak forest and avoiding barren areas. However, the directions followed by postbreeding migrants leaving the pond differed from those they followed when coming to the pond. 3.The distribution of captures around the pond was related to environmental factors, and more precisely to vegetation within the immediate surroundings of the pond. 4.The environmental conditions occurring at the end of the spring postbreeding migration differed greatly from those occurring during the winter prebreeding migration. Thus, vegetation does not exert similar attraction during the two migration periods. 5.This raises the importance of microhabitat diversity in the vicinity of the breeding pond, which provides a wide range of suitable shelters in different migration periods. Conservation planning must take into account the ecological requirements of this endangered species in managing buffer zones around the breeding sites. Copyright © 2005 John Wiley & Sons, Ltd. [source] The Extent, Distribution, and Fragmentation of Vanishing Montane Cloud Forest in the Highlands of Chiapas, Mexico,BIOTROPICA, Issue 4 2006Luis Cayuela ABSTRACT Montane cloud forest (MCF) has high levels of species diversity, contributes positively to the catchment water yield, and is a globally threatened habitat type. The shortage of reliable data regarding the area currently occupied by MCF remains an obstacle to operational conservation planning in Mexico. This paper assesses how much MCF remains in the central Highlands of Chiapas (Mexico) and how fragmented it is in relation to other forest cover. We estimated that the area covered by MCF was between 3700,5250 ha. This estimate contrasted with the approximately 40,000 ha reported for the same region by the Mexican National Forestry inventory in 2000. MCF was highly scattered and fragmented within a matrix of other tropical montane forest types. Other forest types may be partially buffering the remaining MCF habitats, however, mitigating their disturbance and enhancing their connectivity. We conclude that mechanisms should be sought to promote the protection of core areas containing MCF fragments in agreement with communal and private landowners and to conserve the ecological functions of surrounding buffer zones. Such a conservation strategy would match the natural configuration of these endangered habitats. RESUMEN El Bosque Mesófilo de Montaña o Bosque Nublado (BN) es un ecosistema único y de gran valor ecológico. Ello se debe, en parte, a la gran diversidad de especies que alberga y al papel que juega en la captación del agua. Aunque estos bosques se encuentran amenazados a nivel mundial, no existen datos fiables sobre la superficie que ocupan actualmente ni su distribución. Esto impide la elaboración de estrategias concretas de conservación. En el presente trabajo se investiga cuánto Bosque Nublado queda en Los Altos de Chiapas (México) y cuán fragmentado se encuentra en relación a otras formaciones forestales. Los resultados de este estudio sugieren que todavía existen entre 3700,5250 ha en el área de estudio. Estas cifras contrastan notablemente con las cerca de 40,000 ha obtenidas por el Inventario Forestal Nacional de México del año 2000. Los remanentes de BN se encuentran muy dispersos, fragmentados e inmersos en una matriz constituida mayormente por otros tipos de bosques tropicales de montaña. Sin embargo, la existencia de otras formaciones forestales que aparecen entremezcladas con el BN podría favorecer la conectividad de estos hábitats y mitigar, al menos en parte, la perturbación a la que están sometidos. Concluimos que es necesario buscar distintos mecanismos para promover la protección de áreas protegidas que contengan los remanentes actuales de BN en acuerdos establecidos con las comunidades y los propietarios de los predios, y la conservación de las funciones ecológicas de las áreas forestales colindantes. [source] | ||||||||||||||||||||||||||||||||||