An Assessment of Microevolutionary Change among Prehistoric Florida Populations through the Analysis of Craniometric Data

The analysis of craniometric data collected from skeletal remains, combined with archaeological data, can provide very valuable information pertaining to biological distance and gene flow among prehistoric populations through space and time. The goal of this study was to examine microevolutionary change among prehistoric populations in south Florida based on the degree of cranial variation among populations at seven prehistoric sites. It was expected that as time progressed, microevolutionary forces caused significant changes in the crania of the various populations based on the relative geographic proximity of the sites and the temporal distance between sites. A Microscribe 3-DX digitizer was used to collect coordinate data using the full protocol of cranial landmarks. Twenty-three interlandmark distances for n=223 skulls from seven sites, ranging in age from 8120 B.P. to 260 B.P., were analyzed using Cluster Analysis, an Analysis of Variance (ANOVA), a Tukey’s Pairwise Comparison (post-hoc test), a Multiple Analysis of Variance (MANOVA), and Principal Components Analysis (PCA) in SPSS 18.0. The seven sites were Windover (8Br246), Perico Island (8Ma6), Captiva Island (8Ll57), Belle Glade (8Pb40), Horr’s Island (8Cr41), Safety Harbor (8Pi2), and Fuller Mound A (8Br90). Of the 223 crania used, zero (0) skulls were 100% complete. Results of univariate and multivariate statistical analyses indicate that there are significant differences among the seven groups. The agglomerative cluster analysis did not provide significant results. When using Maximum Cranial Length (GOL), the ANOVA (F=5.190, p ≤ 0.000) and post-hoc tests indicated that there was a significant amount of variation among the seven populations. In a series of 12 MANOVA tests, it was determined that significant variation existed between Windover and each of the remaining six sites (F \u3e 5, p ≤ 0.000). Additionally, the MANOVA tests indicated that significant variation existed between Horr’s Island and Safety Harbor (F = 8.151, p ≤ 0.000) and between Safety Harbor and Fuller Mound A (F = 5.549, p ≤ 0.000). Last, a Principal Components Analysis demonstrated that measurements consistent with length or breadth accounted for the largest percentage of variation among the populations. In conclusion, the data strongly demonstrate a significant amount of variation among prehistoric populations as time progressed from 8120 B.P. to 260 B.P. Specifically, changes in gene flow which can be attributed to significant differences among populations based on craniometric data parallel major time gaps and historical events in Florida. More generally, these results can be applied to other past populations to investigate similar patterns of gene flow and changes that may have occurred due to various social, political, and environmental stressors

Evaluation of planning policy for protecting green infrastructure from loss and degradation due to residential encroachment

Studies indicate substantial degradation and loss of urban green infrastructure area following adjacent residential development. A content analysis of Ontario's most authoritative policy documents was performed to determine whether they had policy goals, objectives and tools for protecting designated green infrastructure from the negative impacts of residential encroachment. Results indicate few policy goals, or measurable objectives. Furthermore, few policy tools sought to limit residential encroachment within green infrastructure following point of development. Existing local government policy tools were narrowly focused on establishing boundary structures and education programs among adjacent residents, without specifying impacts of concern. Policies requiring the monitoring of impacts and tools for their mitigation were missing. Long-term protection policy goals, measurable policy objectives, and effective policy tools are required to limit the anticipated negative impacts associated with residential encroachment following development. Where impacts are uncertain, monitoring policies are required to test and improve policy effectiveness. Furthermore, adaptive management policies are required to protect essential ecosystem services from unanticipated long term impacts, such as those arriving with climate change

Barriers to the effective planning and management of residential encroachment within urban forest edges: A Southern Ontario, Canada case study

Studies document degradation and loss of publicly owned urban woodland area following adjacent residential development due to residential encroachment. Residential encroachment is the negative impacts of housing land uses within both rural and urban green infrastructure networks. Prevailing planning, design and management approaches in Southern Ontario municipalities in Canada indicate planning and management tools have been developed to remove and impede encroachment impacts; however, many are infrequently implemented. This lack of implementation contributes to a high prevalence and spatial area of encroachment within Southern Ontario municipal woodland edges with adjacent housing. Long interviews were conducted with the planners, landscape architects, woodland managers and bylaw enforcement staff of six Southern Ontario municipalities to determine the barriers to implementation of municipal encroachment tools. Results indicate key barriers to policy implementation that reflect a lack of awareness of, and priority placed on addressing, residential encroachment impacts, and impacts following the point of development in general. Barriers include: (1) insufficient community and municipal access to information regarding residential encroachment and their significance relative to other development impacts; (2) lack of clarity of goals by municipalities and between departments; (3) insufficient municipal leadership and commitment to limiting encroachment; (4) lack of sufficient means within municipal departments to prevent and address encroachment; and (5) ineffectual dynamics of enforcement. Recommendations for overcoming barriers to the development and implementation of effective approaches for addressing encroachment are provided

Evaluation of planning and management approaches for limiting residential encroachment impacts within forest edges: a Southern Ontario case study

Studies increasingly document degradation and loss of publicly owned urban forest area following adjacent development due to residential encroachment. Little is known about prevailing approaches for limiting these impacts. Taking Southern Ontario as a case study, long interviews were conducted among Ontario planners, landscape architects, forest managers and bylaw officials within six Ontario municipalities to determine prevailing goals, tools, and strategies for addressing residential encroachment. Few municipalities had explicit goals, and none had objectives for addressing encroachment. Bylaws were the primary tools for addressing existing encroachments, but field studies indicated infrequent enforcement. Boundary-focused structures, such as fences, were the primary means of preventing encroachment; however, they were applied to a minority of forests with adjacent housing. None of the municipalities had a strategy for implementing their tools to protect targeted ecological, social or economic services provided by urban forests. Recommendations for improved approaches for managing residential encroachment impacts within forest edges are provided