Community-Based Monitoring in support of local sustainability

Community-based monitoring (CBM) activities in Canada are increasing. A conceptual framework developed for and used to guide a pilot CBM project in 31 Canadian communities is evaluated. The framework provided the strategic direction necessary for successful implementation of the pilot and proved useful in the training of community coordinators hired for the project. Limitations of the framework include its inadequate attention to community diversity, its linearity, and insufficient expression of the adaptive and synergistic nature of its components. In order to support local sustainability, CBM appears to require an approach that is context-specific, iterative, and adaptive. Given these emergent characteristics, an enhanced conceptual framework for CBM in Canada is developed based on four dynamic themes: community mapping, participation assessment, capacity building, and information delivery.     

Reply to Discussion1 - by George Ice,George Brown,John Gravelle,C. Rhett Jackson,Jeff Light,Timothy Link,Douglas Martin,Dale McGreer,and Arne Skaugset2 “Stream Temperature Relationships to Forest Harvest in Western Washington”3

Pollock, Michael M. and Timothy J. Beechie, 2010. Reply to Discussion –“Stream Temperature Relationships to Forest Harvest in Western Washington” by George Ice, George Brown, John Gravelle, C. Rhett Jackson, Jeff Light, Timothy Link, Douglas Martin, Dale McGreer, and Arne Skaugset. Journal of the American Water Resources Association (JAWRA) 46(4): 843-847. DOI: 10.1111/j.1752-1688.2010.00456.x     

Does Riparian Forest Restoration Thinning Enhance Biodiversity? The Ecological Importance of Large Wood

Intact riparian ecosystems are rich in biological diversity, but throughout the world, many have been degraded. Biodiversity declines, particularly of vertebrates, have led to experimental efforts to restore riparian forests by thinning young stands to accelerate creation of large diameter live trees. However, many vertebrates depend on large diameter deadwood that is standing as snags or fallen to the forest floor or fallen into streams. Therefore, we reviewed the sizes of deadwood and live trees used by different vertebrate species to understand which species are likely to benefit from different thinning treatments. We then examined how riparian thinning affects the long‐term development of both large diameter live trees and deadwood. To this end, we used a forest growth model to examine how different forest thinning intensities might affect the long‐term production and abundance of live trees and deadwood. Our results suggest that there are long‐term habitat tradeoffs associated with different thinning intensities. Species that utilize large diameter live trees will benefit most from heavy thinning, whereas species that utilize large diameter deadwood will benefit most from light or no thinning. Because far more vertebrate species utilize large deadwood rather than large live trees, allowing riparian forests to naturally develop may result in the most rapid and sustained development of structural features important to most terrestrial and aquatic vertebrates.     

牛栏江流域(昆明段)水质现状、存在问题及对策研究

牛栏江是金沙江的一级支流,为常流河,在昆明境内由多条河流汇集而成,通过对牛栏江流域(昆明段)水质现状分析,阐述了流域内存在的环境保护问题,提出相应的对策措施和建议.     

Predator-prey relationships between the rock lobster Jasus lalandii and the mussel Aulacomya ater at Robben Island on the Cape West Coast of Africa

The natural diet and mode of feeding of the rock lobster Jasus lalandii (H. Milne Edwards) was determined in a rock-lobster sanctuary near Cape Town, South Africa. Field observations were tested and confirmed by means of aquarium studies. Rock lobsters feed mainly upon ribbed mussels Aulacomya ater (Molina), which comprise the largest component of the sessile benthic fauna. Mussel remains were found as the major constituent in 97% of the rock-lobster stomachs examined. The density of rock lobsters averaged 8,100 per hectare (0.81 m^-2), while mussel biomass averaged more than 5 kg (wet whole weight) m^-2 within the same depth range (12 to 30 m). More than 80% of the mussel biomass comprised large individuals between 60 and 90 mm in length. Large rock lobsters (mainly males) were capable of feeding on all sizes of mussels, although many of these were inaccessible to predation. Smaller rock lobsters became progressively more limited in the size range of mussels which they could crack open and consume. Competition between rock lobsters for small mussels appeared to be intense, as mussels of suitable size for feeding were generally in short supply to most of the rock-lobster population. Hence, feeding and growth rates of rock lobsters are likely to be affected by the relative population densities of predator and prey. Growth rates of rock lobsters could be limited by food supplies even in areas where mussel biomass is comparatively large.     

Mark-recapture estimators for dual frame population size of prominent nesting structures: the effect of uncertain detection probability

The combined mark-recapture and line transect sampling methodology proposed by Alpizar-Jara and Pollock [Journal of Environmental and Ecological Statistics, 3(4), 311–327, 1996; In Marine Mammal Survey and Assessment Methods Symposium. G.W. Garner, S.C. Amstrup, J.L. Laake, B.F.J. Manly, L.L. McDonald, and D.C. Robertson (Eds.), A.A. Balkema, Rotterdam, Netherlands, pp. 99–114, 1999] is used to illustrate the estimation of population size for populations with prominent nesting structures (i.e., bald eagle nests). In the context of a bald eagle population, the number of nests in a list frame corresponds to a pre-marked sample of nests, and an area frame corresponds to a set of transect strips that could be regularly monitored. Unlike previous methods based on dual frame methodology using the screening estimator [Haines and Pollock (Journal of Environmental and Ecological Statistics, 5, 245–256, 1998a; Survey Methodology, 24(1), 79–88, 1998b)], we no longer need to assume that the area frame is complete (i.e., all the nests in the sampled sites do not need to be seen). One may use line transect sampling to estimate the probability of detection in a sampled area. Combining information from list and area frames provides more efficient estimators than those obtained by using data from only one frame. We derive an estimator for detection probability and generalize the screening estimator. A simulation study is carried out to compare the performance of the Chapman modification of the Lincoln–Petersen estimator to the screening estimator. Simulation results show that although the Chapman estimator is generally less precise than the screening estimator, the latter can be severely biased in presence of uncertain detection. The screening estimator outperforms the Chapman estimator in terms of mean squared error when detection probability is near 1 wheareas the Chapman estimator outperforms the screening estimator when detection probability is lower than a certain threshold value depending on particular scenarios.