Analisi spaziali in studi di sostenibilità e conservazione di risorse agrarie e forestali
Author(s)
Chiocchini, Francesca
Date Issued
May 27, 2013
Type
Doctoral Thesis
Abstract
Rapid growth of human pressure on natural resources has led profound changes in the natural environment.
Destruction and degradation of natural habitats are widespread and profound and their implications for the
conservation of biological diversity and the sustainability of natural resources are of global significance.
Survival and spread of many species, and even of entire biomes, are seriously at risk for the rapidity of
global warming, deforestation, land use changes and human activities.
Remnants of the natural environment increasingly occur as a mosaic of large and small patches, survivors of
environments that have been carved up to develop new forms of productive land use for humans.
Many species have suffered local extinctions due to fragmentation and loss of natural habitats, while their
ability to expand and re-colonize is hampered by the low degree of connectivity between the landscape
fragments. Biodiversity conservation depends, therefore, by the maintenance of functional ecological
networks and by the specific capacity of adaptation in fragmented habitats. Initiatives aimed at sustainability
and agricultural and forestry resources preservation are needed to slow down biodiversity loss and to restore
habitat connectivity.
The need to understand the complex interactions between biological, physical and socio-cultural components
that have produced the current landscape, has stimulated the development of interdisciplinary methods,
which consider the landscape, and all the variables associated with it, as a fundamental element of analysis.
Research in the field of landscape ecology has improved understanding of both the causes and the
consequences of spatial heterogeneity, and how these vary with scale, coming to an effective influence on
management of both natural and man-shaped landscapes. GIS spatial analysis functions are now essential to
investigate the spatial nature of biological, physical and anthropic landscape components and their
relationships. These are the tools of the trade of fundamental analysis in studies of sustainability and
conservation of natural resources.
The aim of this thesis was to investigate the potential application of spatial analysis in four case studies,
exploring the possibility to integrate data and methods from various disciplines, such as ecology and
ecophysiology, population genetics and landscape analysis through the use of GIS spatial analysis tools. The
thesis is the result of an interdisciplinary research involving working groups in plant eco-physiology,
physiology of stable isotopes and population genetics.
The first case study focuses on the conservation and sustainability of Amazonian natural resources in the
municipality of Moju (Pará, Brazil), where a fast development of human activity caused rapid deforestation
in the last decades. Deforestation is associated to various determinants: the expansion of the urban area of
Moju; the spread of an extensive primary and secondary road network; the expansion of cropland, palm oil
plantations and cattle ranching. As a whole, it results in high fragmentation of primary forest in this area.
Several techniques have been adopted and integrated: remote sensing and spatial analysis to estimate
deforestation; land cover and land use analysis to estimate carbon sequestration capability of a sample site;
landscape ecology methods for the identification of spatial patterns of landscape structure; strategies for
forest restoration.
Results show an increase in deforestation by 6% between 2001 and 2008, but a slight decrease in
deforestation rate, annual forest loss amounting to 90-100 km2, with a deforested area greater than 40% of
the municipal area in 2008.
Main spatial patterns, observed in year 2008 images, of different shape and size, witness profound changes in
land use through 1984-2008. Variation of NDVI values (Normalized Difference Vegetation Index) observed
between 1984 and 2008, shows forest degradation and fragmentation highlighting the expansion of inhabited
areas.
In Moju region human activity has grown strongly over the past few decades, leaving the country in a state
of degradation and fragmentation, thus putting in serious crisis the ecological network functionality. Land
cover and land use analysis on a 7700ha sample site, complemented with data from the literature, estimate a
carbon stock amounting to 0.65 million tons. This stock would potentially double in an intact territory.
A recovery and conversion model has been proposed to cope with these emergencies, according to the socalled
legal reserve (federal Brasilian law for the recovery of secondary forests), on an enterprise scale. Such
a conversion would stimulate the restoration of ecosystem functions essential to the resettlement of the forest
itself and the spontaneous recovery of its biodiversity, resulting in the gradual consolidation of the local
ecological network.
The second and the third case study investigate the origin and the processes that have affected the current
distribution of Castanea sativa in Europe, and Juglans regia in Asia, through the analysis of the spatial
structure and genetic diversity of existing populations, in relation to landscape and environmental variables.
The aim is to apply landscape genetics, combining data and methods of landscape ecology and population
genetics to understand the spatial genetic structure of populations and the effects of the landscape matrix on
gene flow and genetic variability.
The overlay technique, identifies the main clusters of populations (genetic structure), barriers and genetic
discontinuities, and interpolates genetic variables to construct genetic isolines, allowing the identification of
coincidences between topographical discontinuity and genetic barriers.
The testing of the overlay technique and the processing of cartographic output are, specifically, the aim of the
second case study. The combination of geostatistical analysis (interpolation of the Q-membership by IDW or
kriging) and genetic structure analysis, outputs a well-defined genetic structure and apparent genetic
discontinuity between the 19 European populations of C. sativa examined. The distribution of different gene
pools, identified through analysis of genetic structure and diversity, reflects the hypothetical location of
glacial refugia of the species.
The third case study illustrates the application of the overlay technique to quantify the effects of landscape
composition (post-glacial expansion, environmental and physical barriers), on gene flow and genetic
variability of spatial resources of J. regia in the native range. This work provides a contribution to the project
WA.L.NET, which represents the first large-scale evaluation of genetic resources of J. regia currently in the
indigenous area. Although J. regia has been intensively manipulated by humans over the last 2000 years, the
results indicate that multiple centers of genetic diversity still exist in the Caucasus and in the mountainous
regions of Central Asia, where J. regia survived after the Pleistocene glaciations.
Genetic discontinuity and clear separation of the 39 walnut populations in four main clusters have been
identified: the first one corresponding to the genotypes of Kyrgyzstan, from the mountains of western Tien
Shan (Central Asia), the second predominant in western and south-central Asia, the third consists of
individuals from east-central Uzbekistan (Nurata), the fourth consisting of individuals from the eastern and
northern China (Xinjiang and Shandong provinces). The overlay technique suggests that current walnut
genetic resources are the result of the combination of two factors: the geographical distance and the
landscape resistance. It is possible to hypothesize that the presence of high mountain ranges (Himalaya, Tien
Shan, Pamir, Hindu Kush, Zagros) and the progressive desertification of Central Asia during the Holocene
have caused repeated events of fragmentation and genetic isolation of walnut populations after the LGM.
Furthermore, as indicated by palynological studies, the complexity of the geographical area of native J. regia
would have favored multiple glacial refugia, from which the genetic differentiation of the current populations
of Persian walnut started.
Finally, the fourth case study is an innovative contribution to traceability study of the geographical origin of
extra virgin olive oil, resulting from combining stable isotope analysis techniques (IRMS) and spatial
analysis of the variability of such isotopic values.
In view of the globalization of markets, the agro-food quality is one of the most promising prospects for
Italian farming. The product qualification and competitiveness must point to a high standard. The traceability
analysis of the geographical origin of food is an important condition to protect the products and origin (PDO,
PGI, organic products), to which the consumer is inclined to provide an added value, and to ensure their
safety. Recent advances in isotope ratio mass spectrometry, coupled with elemental analysis and pyrolysis,
allow the measurement of the isotopic ratios of light elements and the identification of the geographical
origin of extra virgin olive oil. The combination of stable isotope techniques and spatial analyses of delta-18-O and
delta-13-C isotopic values made possible to represent the spatial variability of the isotopic composition of 122
samples of Italian olive oil (Lombardia, Liguria, Toscana, Lazio, Molise, Puglia, Calabria, Sicilia and
Sardegna).
This is the first known attempt of integration of isoscapes analysis in traceability studies of olive oils. The
results indicate a splitting of the samples in four distinct areas: north, south-central Tyrrhenian, south-central
Adriatic and islands. This division mainly depends on the geographical variability of climatic conditions in
the Mediterranean basin. Homogeneous regions, based on spatial interpolation, provide a zonation of the
expected isotopic signatures, which can be used to guarantee the origin of an extra virgin olive oil. The
method appears promising in defining a protocol analysis of georeferenced data, with the aim of contrasting
fraud and adulteration in the food industry.
Additional information
Dottorato di ricerca in Scienze e tecnologie per la gestione forestale e ambientale
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