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Irina Rasputnis
UEP 232 – Intro to GIS
18 September 2009
Assignment 1 – Example of GIS
Article: Global warming and biodiversity: Evidence of climate-linked amphibian declines in Italy
Researcher: Manuela D’Amen and Pierluigi Bombi
Source: Biological Conservation xxx (2009) xxx-xxx (article in press)
URL: http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V5X-4X4G2RJ-33&_cdi=5798&_user=201547&_orig=search&_coverDate=09/01/2009&_sk=999999999&view=c&wchp=
dGLbVlz-zSkWz&md5=e1aa965321b2e56675d7690ebe404573&ie=/sdarticle.pdf
In this article, spatial patterns of recent amphibian declines are used to test a hypothesis pertaining to
three potential factors for the decline: climate change, habitat alteration, and high levels of solar
radiation. A geographic grid containing Italy was divided into 3557 grid-squares in which presence of up
to 19 amphibian species was documented at the beginning and end of the study period. Using GIS,
mean values and shift in these mean values were calculated for each grid cell to represent the three
potential factors. Based on this data, a common pattern of species decreases and disappearances was
identified in areas that have been especially affected by climactic shifts. Through the use of predictive
models, climate change was identified as the major cause of population decreases and disappearances.
Habitat alteration was also found to contribute to the decline of several species and solar radiation was
found to potentially be an important factor in association with other stressors. Using the results of this
study (identification of most threatened species, finding geographical hot spots of decline, and the
causes of decline), this study provides a basis for improving conservation policy.
Italian amphibian data was collected by hundreds of volunteers through field sampling as part of
regional atlas projects conducted across Italy in the 1990s and early 2000s. This data was compiled to
produce the CKmap databank, which is the largest, most authoritative resource of Italian faunistic
knowledge. Records of each species’ record were accompanied by the year of last (most recent)
observation (YLO). This data was mapped to the 3557 cells. If the YLO indicated that the species
experienced a population decline in a particular cell, the attribute DECLINE was assigned to that cell. If
the YLO indicated the species did not decline in population, the attribute STABLE was assigned to the
cell.
The geographic pattern of climate change in Italy was represented using three variables that describe
factors known to influence amphibian biology: annual number of dry days (DD), annual precipitation (P),
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and annual mean temperature (T). The values for these parameters were provided by the SCIA
databank, a national system for collection, elaboration, and diffusion of climatologic data of
environmental interest. These data were analyzed in ArcGIS to produce climactic surfaces representing
their geographic variation across Italy with a spatial resolution of 4 x 4 km. Mean values were calculated
for the period 1961-1990 and mean shift (variance) values were calculated for the decades 1961-1970
and 1981-1990. The geographic surfaces were resampled at a 10 x 10 km resolution.
Similarly, habitat modification was represented by agricultural (AG) and urban (UR) land cover areas
from the Corine Land Cover 1990 data provided by the National Environmental Information System.
Solar radiation incidence was compiled from data from the Joint Research Center. Figure 1 shows the
results of the study.
Figure 1. Predictors and patterns of decline. (a–g) Environmental surfaces utilized as proxies of the decline hypotheses: (a)
DD VAR (pale gray: _3.32 d, black: 45.76 d); (b) DD MEAN (pale gray: 0 d, black: 303.14 d); (c) T VAR (pale gray: _2.26 _C,
black: 7.76 _C); (d) P VAR (pale gray:125.64 mm, black: _904.75 mm); (e) AG (pale gray: 0% of agricultural surface, black:
100% of agricultural surface); (f) UR (pale gray: 0% of urban surface, black: 91.80% of urban surface); (g) IR (pale gray: 4.482 _
106 J/m2, black: 6.486 _ 106 J/m2). See text for variable descriptions. (h) Percentage of declining species per cell (pale gray:
0% black: 100%). In all figures darkness of the pixels are proportional to cell values.
There is no way this study could have been conducted without mapping and spatial analysis. I would be
interested to know what the results look like with more current data.
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