Marissa Simpson
NRS 509
12/16/14
Application of GIS in Habitat Assessment for Birds
Climate change has caused a major loss in biodiversity over the last fifty years. One of
the contributing factors to the loss in biodiversity is the degradation of habitats. Across the
globe, habitat degradation and loss has caused eighty-five percent of the threatened bird species
to be at risk (Ronka et al., 2008). Geographical information systems (GIS) are a crucial tool in
habitat assessment for birds. Some GIS processes that are used in habitat assessment are Kriging,
interpolation, and habitat suitability models. The information retrieved from the habitat
assessment can then be used to assist in the conservation of birds.
A habitat is comprised of the abiotic factors that are needed for the organism’s survival
(Dong et al., 2013). An issue for different bird species is the loss, degradation, and
fragmentation of their habitats. One of the main influences on the state of a habitat is pollution,
land use and other human activity (Dong et al., 2013; Ronka et al., 2008; Store & Jokimaki,
2003). One of the ways that a threatened bird species can be protected is to identify and locate
the bird species’ habitat prior to the human activities that are likely to negatively affect the
habitat (Store & Jokimaki, 2003). GIS becomes an important tool when trying to locate these
habitat location. Different GIS techniques are used in order to conserve and manage the bird
species.
GIS is utilized in habitat assessment by creating habitat models. Habitat models compare
the environmental factors that affect the abundance and distribution of the species (Dong et al.,
2013). These models are useful in determining the habitat preferences of species by combining
previous theories and field research (Ozesmi & Mitsch, 1997). A habitat is defined as the
combination of abiotic factors, therefore, choosing which factors go into the habitat model is
dependent on the abiotic factors within the study area (Dong et al., 2013). Some of the typical
factors that comprise a habitat are nest locations, bathymetry, vegetation, open water maps,
topography, water depth (Ronka et al., 2008; Ozesmi & Mitsch, 1997). The scripting utility in
the GIS system is used to create algorithms that prepare the data layers for statistical analysis
(Ozesmi & Mitsch, 1997).
The sources of data for the data layers that are utilized in the habitat assessment models
are a combination of satellite imagery and vector data. Some of the sources of the satellite
imagery are from the Landsat Thematic Mapper and Digital Elevation Model data (Dong et al.,
2013). Satellite imagery is valuable because of its ability to collect data over a vast area. The
Thematic Mapper data were used in order to identify polygon assessment units that had similar
spectral and spatial characteristics (Dong et al., 2013). Some studies also employed the use of
aerial photography in order to extract vital information that can be used in a habitat model
(Ozesmi &Mitsch, 1997). Some other information for modeling was taken from land cover data.
An important element that is crucial to the model is bird distribution data (Romero-Calcerrada &
Luque, 2006). The combination of all the different sources of data create the habitat model which
can be applied to conservation techniques.
Before data can be used in habitat analysis it must be preprocessed. One of the most
commonly used process when performing habitat assessment involves the processes of overlay
analysis and the Kriging method. To begin the process, field data was collected including data
such as nest sites, types of vegetation, water depths, etc. (Ozesmi & Mitsch, 1997). In some
cases aerial photography was used and then converted into raster form by using the Isodata
algorithm in unsupervised classification methods (Ozesmi & Mitsch, 1997). A base map can
then be created based on the topography of the study area and aerial photograph. Digital Terrain
Models (DTM) can be used as a base map by using elevation, orientation, and slope values to
create it. (Brambilla et al., 2009). Once the base map is created, the field data can be added to
the map. Some of the data including habitat factors such as water depth may need to undergo
Kriging in order to prepare the data as bathymetry. Once all of the factors are prepared, the data
can be recoded, covered, spread, and then interpolated. A logistic regression is then used to order
to create a habitat model (Ozesmi & Mitsch, 1997).
Once the data is preprocessed it is ready to be used for the creation of a habitat suitably
model. A habitat suitability model analyzes the preprocessed data to develop suitability indices
based on habitat factors. A habitat assessment models can be used when the distribution of a bird
species and the habitat factors are overlayed to determine habitat preference (Ozesmi & Mitsch,
1997). A spatial habitat model can also be used when habitat preferences or breeding habitat
preferences are known and are used to predict the distribution of a species (Brambilla et al.,
2009; Ronka et al., 2008).
When creating a habitat suitability model every habitat factor is converted to a raster
layer. The final product of the suitability index is the combination of all of the indices (Store &
Jokimaki, 2003). Every pixel correlates to values in the attribute table. After the conversion of
the habitat factors into a raster layer, the suitability model can be made based on an empirical
regression model. The overall score, resulting from the regression model is the combination of
all the indices scores, is transformed into units that can be displayed on the map (Store &
Jokimaki, 2003). The combined index was calculated using the grades good, fair, poor and not
suitable (Dong et al., 2013). Areas that would be an ideal habitat for the birds based on the
habitat factors put into the model will be differentiated from those of poor habitat quality (Store
&Jokimaki, 2003). After the creation the model, the model is then verified and validated, so that
it can be used for analysis (Ozesmi & Mitsch, 1997). After performing the habitat model, the
models can be used in order to do analysis on the topic of the study.
The information derived from the habitat models can be used in conservation and
management efforts for different bird species. An example of the usage of information
implemented can be seen in the management of the Three-toed woodpecker in Finland. The
habitat suitability model assisted in predicting the locations of woodpecker pairs. The correlation
of the breeding locations and habitat characteristics was essential in determining the need for
Three-toed woodpecker habitat protection (Romero-Calcerrada & Luque, 2006). A second
example of the usage of habitat suitability models can be found in the conservation of waterbirds
in the West Songnen Plain, China. Using the model, it was predicted that the degradation of the
wetlands will be the biggest threat to the waterbirds. Policies and measures were then
implemented in order to protect the waterbird habitats (Dong et al., 2013).
As humans continue to encroach on bird habitats and efforts in habitat conservation are
increased, GIS will have a greater role in the habitat assessment. Advances in technology will
provide more detailed and complex data that can be used for habitat assessment. GIS will
become a more valuable tool in the analysis of this data. The usage of habitat modeling in GIS
will continue to be a good starting point when trying to conserve the birds in the study sites.
There are also some limitations that using GIS cannot overcome when performing habitat
models. GIS systems cannot account for factors such as competition and influences of other
organism (Dong et al., 2013). The GIS model are useful on a coarse scale to conservationists
because they help to identify the sites of potential bird habitats. However, on a finer scale the
models cannot be utilized because it lacks enough detail for drawing site level conservation
measures (Brambilla et al., 2009). Overall, GIS can analyze vast amounts of data to correlate
important habitat information that could not be obtained without the use habitat assessment
models. However, there are limitations that have to be taken into account when using GIS in the
habitat assessment of birds.
Climate change and human activity is having negative impacts on the habitats of different
bird species across the globe. In order to assist in the conservation of the birds, GIS techniques
such as overlay analysis, Kriging, and habitat suitability model assist in locating the at risk
habitats. By protecting the habitats, there is hope that there will be a positive outcome for the
conservation of bird species. GIS is an essential tool and should be utilized when performing
habitat assessments, with the proper precautions in mind.
Annotated Bibliography
Brambilla, M., Casale, F., Bergero, V., Crovetto, G.M., Falco, R., Negri, I., Siccardi P.,
Bogliani, G. 2009. GIS-models work well, but are not enough: Habitat preferences of
Lanius collurio at multiple levels and conservation implications. Journal of Biological
Conservation 142: 2033-2042.
As opposed to the other GIS model articles, the article written by Brambilla et al. describes
how GIS models are not enough in order to fully assess an organisms’ habitat. The article
discusses how the GIS model only uses coarse land data which may not be applicable to
effectively determining habitat assessment. The article states that more habitat descriptions
are needed to fully assess the habitats. Some of the other factors that the authors insist on
being accounted for are scale and habitat variables, landscape level, and site-level. After
completing a GIS model of the land factors, the model was compared to the characteristics
of the territories. Based on the comparison the study determined that GIS models can be
used to help identify unknown areas for species. However, GIS models should not be used
for detailed conservation measures. The article was used to show the negative side of GIS
modelling and where a user must use caution when using GIS to perform habitat
assessment.
Dong, Z., Wang, Z., Liu, D., Li, L., Ren, C., Tang X., Jia, M., Liu, C. 2013. Assessment of
habitat suitability for waterbirds in the West Songnen Plain, China, using remote sensing
and GIS. Journal of Ecological Engineering 55: 94-100.
The main purpose of the article written by Dong et al. was to analyze the factors that relate
to the foraging and resting of waterbirds, determine habitat suitability and to analyze the
factors that go into habitat suitability. In this article, both remote sensing and GIS were
used to accomplish the objectives of the article. GIS was utilized to analyze habitat
suitability by comparing abiotic factors of the environment to nest sites. Scores based on
disturbance degree, water situation, food abundance and shelter condition were assigned to
the different study areas. The scale was from 0-100 and the higher the score the better the
habitat site for waterbirds. This article was used to further show the factors that go into
determining habitat assessment, and the process that goes into employing GIS to assess
habitat suitability.
Özesmi, U., & Mitsch, W.J. 1997. A spatial habitat model for the marsh-breeding redwinged blackbird (Agelaius phoeniceus L.) in coastal Lake Erie wetlands. Journal of
Ecological Modeling 101: 139-152.
The article written by Ozesmi and Mitsch demonstrates how spatial modeling can be used
for conservation and management plans in wetlands. Specifically, this study models the
distribution of marsh-nesting birds by environmental factors. Ozesmi and Mitsch use the
Kriging method as a part of the spatial model. The results of this study showed that the
model was successful in showing the location of nest sites of the marsh nesting birds. The
validation of the model was heavily dependent on the environmental factors that went
into making the ecological model. The model concluded that the nest site for marsh birds
was based on vegetation durability and water depth. This article was utilized to show the
validation of GIS modeling in habitat assessment.
Romero-Calcerrada, R., & Luque, S. 2006. Habitat quality assessment using Weights of
Evidence based GIS modeling: The case of Picoides tridactylus as species indicator of the
biodiversity value of the Finnish forest. Ecological Modeling 196: 62-76.
The article written by Romero-Calcerrada describes how habitat assessment maps created
by GIS can help to develop management plans to manage protected areas. In this article,
the authors used the Bayesian method to model the population of the three-toed
woodpecker. The habitat suitability model was utilized to determine the likeliness for the
occurrence of a species. The habitat suitability model was created by comparing
environmental factors and human induces environmental pressures. The information
obtained from woodpecker sightings was used to find sites that were favorable for
nesting. This article was utilized to show another application of GIS in habitat
assessment. In addition, the article shows the different factors that go into habitat
modeling. The Bayesian method was also used to show another technique in habitat
modeling.
Rönkä, M., Tolvanen, H., Lehikoinen, E., Von Numers, M., Rautkari, M. 2008. Breeding
habitat preferences of 15 bird species on south-western Finnish archipelago coast:
Applicability of digital spatial data archives to habitat assessment. Journal of Biological
Conservation 141: 402-416.
In this article, Ronka et al. discusses the application of GIS to analyzing habitat
assessment for birds. The article was utilized to explain how there are different factors
that go into to determining habitat assessment. The main purpose of the article was to
analyze habitats based on different factors against the distribution of fifteen different bird
species. GIS is a powerful tool that can be used for quantitative analysis of the
environmental variables that make up a habitat. GIS was used to quantify the physical
characteristics of bird breeding habitats. Topography, water depth, shoreline openness,
and land area are all factors that go into modeling the likelihood of potential habitat sites.
Information was collected by comparing the distribution with the land factors. The
information gathered from the analysis of the factors has implications in habitat
conservation, bird monitoring, and the preservation of endangered species.
Store, R., & Jokimki, J. 2003. A GIS-based multi-scale approach to habitat suitability
modeling. Journal of Ecological Modeling 169: 1-15.
In order to protect endangered species that are difficult to locate is to protect their habitat
from human activity. The article written by Store and Jokimki describes the usage of GIS
in ecological modelling for habitat assessment. In this study, the habitats for the Pied
Flycatcher and the Redstart were evaluated. The habitat assessment model included
habitat factors such as vegetation and soil properties. Based on the criteria, the areas were
broken down into three habitat categories; unsuitable, suitable and feasible. A map could
then be completed based on the category that the area was placed into. By determining
locations of suitable bird habitats, a forest management plan can be implemented. The
article written by Store and Jokimki was utilized to describe the process of modeling
habitat assessment.