Increase In Number Of Patches Research Articles

Landscape metrics analysis of land use patterns and changes in suburban local government areas of Ibadan, Nigeria

This study examined the spatiotemporal pattern of urban growth and magnitude of changes in selected Local Government Areas (LGAs) in the suburban area of Ibadan using remote sensing cum spatial metrics. Data for the study were obtained from administrative maps of the study area, population data and satellite imageries. All of these were complemented with ground validations using Global Positioning System (GPS) receiver. Periods of change analysis were divided into two epochs; 1986 to 2002 and 2002 to 2017. The imageries were classified into four landuse/cover classes based on Anderson’s modified version of supervised classification scheme. Accuracy assessment of the imageries was carried out using 100 randomly sampled ground truth points. Ten spatial metrics were selected for analysis using Fragstats program. Results show a significant loss in vegetation due to conversion (Land Consumption Rate, LCR = 0.025, 0.019 and 0.027; Land Absorption Coefficient, LAC = 0.012 and 0.048). Moreover, there was a persistent increase in Number of Patches (NP) indicating a scattered and fragmented but continuous development. However, dwindling values of Patch Density (PD = 90.94, 27.07 and 30.30) indicate expansion through conversion of other landuses at varying rates. Results also indicate an incidence of fragmented low density development in the fringe areas (Area Weighted Mean Patch Fractal Dimension, AWMPFD = 1.37 and 1.39). The study highlights the chaotic land development and unrestrained urban expansion in the study area.

The multi-patch logistic equation

<p style='text-indent:20px;'>The paper considers a <inline-formula><tex-math id="M1">\begin{document}$ n $\end{document}</tex-math></inline-formula>-patch model with migration terms, where each patch follows a logistic law. First, we give some properties of the total equilibrium population. In some particular cases, we determine the conditions under which fragmentation and migration can lead to a total equilibrium population which might be greater or smaller than the sum of the <inline-formula><tex-math id="M2">\begin{document}$ n $\end{document}</tex-math></inline-formula> carrying capacities. Second, in the case of perfect mixing, i.e when the migration rate tends to infinity, the total population follows a logistic law with a carrying capacity which in general is different from the sum of the <inline-formula><tex-math id="M3">\begin{document}$ n $\end{document}</tex-math></inline-formula> carrying capacities. Finally, for the three-patch model we show numerically that the increase in number of patches from two to three gives a new behavior for the dynamics of the total equilibrium population as a function of the migration rate.</p>

A quantitative framework for analysing long term spatial clustering and vegetation fragmentation in an urban landscape using multi-temporal landsat data

Rapid urbanization threatens urban green spaces and vegetation, demonstrated by a decrease in connectivity and higher levels of fragmentation. Understanding historic spatial and temporal patterns of such fragmentation is important for habitat and biological conservation, ecosystem management and urban planning. Despite their potential value, Local Indicators of Spatial Autocorrelation (LISA) measures have not been sufficiently exploited in monitoring the spatial and temporal variability in clustering and fragmentation of vegetation patterns in urban areas. LISA statistics are an important structural measure that indicates the presence of outliers, zones of similarity (hot spots) and of dissimilarity (cold spots) at proximate locations, hence they could be used to explicitly capture spatial patterns that are clustered, dispersed or random. In this study, we applied landscape metrics, LISA indices to analyse the temporal variability in clustering and fragmentation patterns of vegetation patches in Harare metropolitan city, Zimbabwe using Landsat series data for 1994, 2001 and 2017. Analysis of landscape metrics showed an increase in the fragmentation of vegetation patches between 1994–2017 as shown by the decrease in mean patch size, an increase in number of patches, edge density and shape complexity of vegetation patches. The study further demonstrates the utility of LISA indices in identifying key hot spot and cold spots. Comparatively, the highly vegetated northern parts of the city were characterised by significantly high positive spatial autocorrelation (p < 0.05) of vegetation patches. Conversely, more dispersed vegetation patches were found in the highly and densely urbanized western, eastern and southern parts of the city. This suggest that with increasing vegetation fragmentation, small and isolated vegetation patches do not spatially cluster but are dispersed geographically. The findings of the study underline the potential of LISA measures as a valuable spatially explicit method for the assessment of spatial clustering and fragmentation of urban vegetation patterns.

Ineffectiveness of local zoning to reduce regional loss and fragmentation of wintering habitat for white-tailed deer

Land-use zoning and regulations are frequently used to protect habitat for species threatened by habitat loss and fragmentation. Habitat protection, however, is rarely followed by habitat monitoring; consequently, knowledge about the efficacy of zoning as a species conservation tool is limited. We used a time series of Landsat satellite imagery (1975–2007) to quantify habitat changes in and adjacent to 187 areas zoned on private, commercial forestlands to protect habitat for wintering white-tailed deer (Odocoileus virginianus) in Maine. Near the northern edge of their geographic range where snow can restrict mobility and access to forage, white-tailed deer depend on mature conifer forests as wintering habitat. Our primary objective was to evaluate effectiveness of land-use zoning to conserve and prevent fragmentation of mature conifer forest. Between 1975 and 2007, the incidence rate of timber harvesting in zoned areas was high (97%). Cumulative area harvested (25%) and the associated reduction of mature conifer forest (13%) that resulted from stand-replacing harvests were considerably lower in zoned areas, indicating that regulations were successful at limiting timber harvests within zones. Reduction of mature conifer forest within unzoned 2-km buffers surrounding protected areas was considerably higher (45%). Remaining patches of mature conifer forest became increasingly fragmented, with a greater than 3-fold increase in number of patches and greater than 80% reduction in mean patch area. Regenerating forest increased from 5% to 36% in the landscapes surrounding zones, and although it can offer important browse, travel across young forest is costly for deer during periods of deep snow. Circa 2007, approximately 55% of the mature conifer forest present across our study area in 1975 remained, and our results suggest that less than 50% of the regenerating areas harvested in mature conifer forest will return to conifer dominance. Forest type conversion will, thus, extend effects of habitat fragmentation into the future. Areas protected for wintering deer collectively represent only 2% of the forested land base in our study area, and we conclude that habitat protection focused solely on those narrowly-defined zones has been ineffective at achieving regional conservation of winter habitat for deer. This study demonstrates how remote sensing can be used to overcome the difficulty of monitoring protected forest areas, and exemplifies the need for monitoring to understand the long-term benefits of zoning as a means of wildlife habitat conservation.

Evaluating urbanization, fragmentation and land use/land cover change pattern in Istanbul city, Turkey from 1971 TO 2002

AbstractSpatiotemporal analysis of landscape dynamics is crucial in formulating an appropriate set of actions in landscape management. This paper presents a large scale analysis of the spatiotemporal structure of Istanbul, a highly urbanized city in Turkey, from 1971 to 2002 using forest cover type maps analysed with geographical information systems (GIS) and a spatial statistics programme. The quantitative evidence indicated that increasing population and expanding urbanization caused drastic changes to the temporal and spatial dynamics of land use/land cover pattern in Istanbul. There was a net increase of 5387·3 ha in total forested areas (1·0 per cent) due to mainly reforestation activities even though the population increased three times over a 31‐year period. Increase in number of patches and decrease in mean patch size together demonstrated that the landscape developed into a more fragmented structure that would negatively affect biodiversity and the resilience of the ecosystems. In conclusion, plain increase in forest areas may not always be a favourable situation. The quality, composition and the configuration of forest landscape should also be analysed to present the dynamics of ecosystem in terms of ecological and economical sustainability over a longer time and larger area. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Landscape changes in the Mullica River basin of the Pinelands National Reserve, New Jersey, USA.

In 1979, the Pinelands Commission was established as a regional land-use planning and regulatory agency charged with the implementation of a Comprehensive Management Plan (CMP) for the Pinelands National Reserve (New Jersey, USA). The CMP was created to balance land preservation and development interests in the Reserve. Because water-quality degradation from developed and agricultural landscapes is associated with changes in the composition of biological communities, monitoring landscape changes provides one of the most direct measures of the impact of land-use policies on the Pinelands ecosystem. In this study, we prepared detailed, land-cover maps within randomly selected aerial-photograph plots for a major watershed in the Reserve. We used these land-cover maps to quantify changes in landscape composition and structure (i.e., patch size, patch area, and number of patches) and characterize land-cover transitions in the basin between 1979 and 1991. Because the study period represented the first 12 years of the regional-planning effort in the Reserve, we evaluated the relationship between land-cover transitions and Commission management-area designations which permit different land-use intensities. Although the landscape composition was similar in 1979 and 1991, we found an increase in the total area and number of developed-land, managed-grassland, and barren-land patches. An increase in the number of patches and a decrease in the total area and median and third-quartile patch sizes for forest land and for all patches regardless of cover type indicated that fragmentation of forest land and the landscape as a whole occurred during the study period. The major land-cover transitions that occurred during the period were the loss of forest land to development and associated cover types and the conversion of one agricultural type to another. Overall, land-cover transitions during the period were found to be consistent with the Commission management-area designations, which indicated that the regional-planning effort has been successful in directing human activities to appropriate areas of the basin.