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Whither the Rangeland?: Protection and conversion in California's Rangeland ecosystems.

ABSTRACT: Land use change in rangeland ecosystems is pervasive throughout the western United States with widespread ecological, social and economic implications. In California, rangeland habitats have high biodiversity value, provide significant habitat connectivity and form the foundation for a number of ecosystem services. To comprehensively assess the conservation status of these habitats, we analyzed the extent and drivers of habitat loss and the degree of protection against future loss across a 13.5 M ha study area in California. We analyzed rangeland conversion between 1984 and 2008 using time series GIS data and classified resulting land uses with aerial imagery. In total, over 195,000 hectares of rangeland habitats were converted during this period. The majority of conversions were to residential and associated commercial development (49% of the area converted), but agricultural intensification was surprisingly extensive and diverse (40% across six categories). Voluntary enrollment in an agricultural tax incentive program provided widespread protection from residential and commercial conversions across 37% of the remaining rangeland habitat extent (7.5 M ha), though this program did not protect rangeland from conversion to more intensive agricultural uses. Additionally, 24% of the remaining rangeland was protected by private conservation organizations or public agencies through land or easement ownership while 38% had no protection status at all. By developing a spatial method to analyze the drivers of loss and patterns of protection, this study demonstrates a novel approach to prioritize conservation strategies and implementation locations to avert habitat conversion. We propose that this approach can be used in other ecosystem types, and can serve as a regional conservation baseline assessment to focus strategies to effect widespread, cost-effective conservation solutions.

SUBMITTER: Cameron DR

PROVIDER: S-EPMC4139198 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Project description:MotivationIn cluster analysis, the validity of specific solutions, algorithms, and procedures present significant challenges because there is no null hypothesis to test and no 'right answer'. It has been noted that a replicable classification is not necessarily a useful one, but a useful one that characterizes some aspect of the population must be replicable. By replicable we mean reproducible across multiple samplings from the same population. Methodologists have suggested that the validity of clustering methods should be based on classifications that yield reproducible findings beyond chance levels. We used this approach to determine the performance of commonly used clustering algorithms and the degree of replicability achieved using several microarray datasets.MethodsWe considered four commonly used iterative partitioning algorithms (Self Organizing Maps (SOM), K-means, Clutsering LARge Applications (CLARA), and Fuzzy C-means) and evaluated their performances on 37 microarray datasets, with sample sizes ranging from 12 to 172. We assessed reproducibility of the clustering algorithm by measuring the strength of relationship between clustering outputs of subsamples of 37 datasets. Cluster stability was quantified using Cramer's v2 from a kXk table. Cramer's v2 is equivalent to the squared canonical correlation coefficient between two sets of nominal variables. Potential scores range from 0 to 1, with 1 denoting perfect reproducibility.ResultsAll four clustering routines show increased stability with larger sample sizes. K-means and SOM showed a gradual increase in stability with increasing sample size. CLARA and Fuzzy C-means, however, yielded low stability scores until sample sizes approached 30 and then gradually increased thereafter. Average stability never exceeded 0.55 for the four clustering routines, even at a sample size of 50. These findings suggest several plausible scenarios: (1) microarray datasets lack natural clustering structure thereby producing low stability scores on all four methods; (2) the algorithms studied do not produce reliable results and/or (3) sample sizes typically used in microarray research may be too small to support derivation of reliable clustering results. Further research should be directed towards evaluating stability performances of more clustering algorithms on more datasets specially having larger sample sizes with larger numbers of clusters considered.

Project description:ImportanceExtreme risk protection order (ERPO) laws temporarily suspend firearm and ammunition access by individuals whom a judge has deemed to be at substantial risk of harming themselves or others. Despite widespread recent adoption of these laws, use of ERPOs has been limited. Barriers to ERPO uptake remain unclear.ObjectiveTo assess public awareness and perceived appropriateness of and willingness to use ERPOs in various risk scenarios, and to identify reasons for being unwilling, overall and by firearm ownership status, to inform efforts to improve ERPO implementation.Design setting and participantsThis was a cross-sectional study using data from the 2020 California Safety and Wellbeing Survey, a statewide internet survey on firearm ownership and exposure to violence and its consequences, conducted from July 14 to July 27, 2020. Adult respondents were recruited from the Ipsos KnowledgePanel using probability-based sampling methods. Responses were weighted to be representative of the adult population of California.Main outcomes and measuresAwareness and perceived appropriateness of gun violence restraining orders (GVROs; California's official term for ERPOs), willingness to use a GVRO for a family member at risk of harm, and reasons for being not at all willing to use a GVRO in 1 or more risk scenarios, overall and by firearm ownership status.ResultsOf the 5018 panel members invited, 2870 (57%) completed the survey. Of these respondents (mean [SD] age: 47.9 [16.9] years; 52.3% women; 41.9% White, 34.7% Latinx, 14.4% Asian, and 5.8% Black individuals), 65.6% (95% CI, 63.0%-68.1) had never heard of a GVRO or a red flag law. Firearm owners were significantly more likely (20.5%; 95% CI, 15.9%-26.0%) than nonowners who live with owners (6.1%; 95% CI, 3.7%-10.0%; P < .001) and nonowners (9.6%; 95% CI, 7.8%-11.6%; P < .001) to have heard of both a GVRO and a red flag law. After reading a brief description of California's GVRO law, 72.9% (95% CI, 70.2%-75.4%) to 78.4% (95% CI, 75.9%-80.8%) of respondents, depending on the risk scenario, indicated that GVROs were in general at least sometimes appropriate, while 73.2% (95% CI, 70.5%-75.6%) to 83.6% (95% CI, 81.2%-85.8%) said they would be somewhat or very willing to use a GVRO for a family member at risk of harm. Firearm owners reported the highest levels of GVRO appropriateness in 4 of 5 risk scenarios (depending on the scenario, 80.0% [95% CI, 73.6%-85.1%] to 85.6% [95% CI, 79.9%-89.8%]). Nonowners who live with owners reported the highest levels of personal willingness to use a GVRO (depending on the scenario, 83.7% [95% CI, 74.7%-90.0%] to 94.7% [95% CI, 86.2%-98.1%]). The most frequently cited reasons for being unwilling to use a GVRO were not knowing enough about GVROs (44.9%; 95% CI, 39.7%-50.3%), believing the risk scenarios are personal or family matters (26.6%; 95% CI, 22.2%-31.6%), and distrust that the system will be fair (23.1%; 95% CI, 19.1%-27.6%).Conclusions and relevanceIn this cross-sectional survey study, public awareness of GVROs was low, but perceived appropriateness of and willingness to use these tools at least some of the time was high. Foci for efforts to address barriers to GVRO use in California were identified; similar challenges likely exist in other jurisdictions.

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Whither the Rangeland?: Protection and conversion in California's Rangeland ecosystems.

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