Reva Gillman
Geog 566
Exercise 3
*I did not use a statistical package to conduct a spatial analysis as stated for exercise 3, as Julia
kindly allowed me to do the spatial analysis within Arc for this exercise.
Part 1.
1. Research question: What is the geographic distribution of the vector history types for
the Japanese Tsunami Marine Debris (JTMD) species? What patterns can be seen with
each vector and the number of JTMD species that were introduced to different regions
of the world because of that method of transport? Which regions are the most
prevalent for certain vector types, and which are least prevalent? Within my spatial
problem, I am asking the following research question type: How are values of the
property y related to one another in space? For my problem, y is the number of species
introduced to each region by a certain vector of interest, and space is geographic coastal
regions. Since I am looking at the number of species introduced to each coastal region, it
is a question of how are the values of y related to one another in space.
2. Spatial statistics notation: Property y, at location i, with neighbors at locations i+h and ih
Yi = f(Yi+h , Yi-h )
3. Spatial processes that my problem involves: attraction and repulsion, dispersal,
diffusion, and advection.
4. I will use inductive reasoning for my spatial problem. By looking at the visual
representation of the vector type distribution of JTMD species, I can develop a theory
based on that information, which entails moving from specific to general. By looking at
the geographic distribution of the JTMD species, I can use observations to develop a
theory of which regions are more likely to have species introduced by certain vector
types.
5. I will be using descriptive statistics for my question: describing a pattern, and drawing
interpretations visually on the JTMD species vector distribution.
6. My spatial problem will not subsume space and time, or consider it irrelevant. I will be
looking at explicit concepts of space to analyze the problem. The spatial dimensions
(geographic regions) are measured in objective units, but the evaluation of the JTMD
species vector distribution is fundamental to the study. Although looking at this explicit
concept of space cannot demonstrate causation, I can get a flexible interpretation of
causes because the geographic regions use location, distance, and arrangement, which
allows for multiple interpretations of the cause of the dispersal of these particular
species.
Part 2.
1. Question that I asked: What is the geographic distribution of the vector history types for
the Japanese Tsunami Marine Debris (JTMD) species? What patterns can be seen with
each vector and the number of JTMD species that were introduced to different regions
of the world because of that method of transport? Which regions are the most
prevalent for certain vector types, and which are least prevalent?
2. Approach that I used: visually represent vector distribution frequency of JTMD species
within 12 different coastal geographic regions of the world, with a different map for
each vector type.
3. Steps I followed to complete the analysis: Using a shape file of the Marine Ecoregions of
the World (MEOW), which are geographic coastal regions that match with my JTMD
species data, in ArcMap, and categorize the 12 realms with different colors. The MEOW
realms are shown below, with the realms labeled. After that was complete, I went
through the JTMD species database for each vector type (Ballast water,
Aquaculture/Fisheries, Moveable Structures, Natural Dispersal, Recreation, and Solid
Ballast) and tallied the number of regions that each species was introduced to via that
particular vector. I made an excel sheet with this data which had a realm column of the
same attribute of the shape file, one tab per vector, and exported the data into my Arc
file. Then I performed a ‘join’ for each vector to its respective spreadsheet in ArcMap, to
align the species data with the geographic shape file. Then I played around with
symbology, choosing for the species sum categorizations for the legend, to arrive with
different maps of the JTMD vector distributions. The following map is of the MEOW
realms:
Marine Ecoregions of the World (MEOW)
4. Results: The most prevalent region that JTMD species are distributed to across all
different vector types is the Temperate Northern Pacific, and the Temperate Northern
Atlantic, along with Southern Australia/ New Zealand. The Temperate Northern Pacific
region seems obvious, as JTMD originated from Japan, so we expect most JTMD species
to be distributed to that same region of the globe. At the other end is the least
prevalent, The Southern Ocean that spans across Antarctica, where no JTMD species
have been introduced.
The map below details the regions that JTMD species have been introduced to via ballast water.
The most prevalent regions are Temperate Northern Pacific, Temperate Northern Atlantic,
along with Southern Australia/ New Zealand, and Southern Africa.
Ballast Water
JTMD Species Vector Distribution
Species / realm
0
1
5
6
7
13-14
The map below shows the number of species that were introduced to each realm through
Aquaculture and Fisheries trade. The most prevalent regions are Temperate Northern Pacific,
Temperate Northern Atlantic, along with Southern Australia/ New Zealand.
Aquaculture
Species / realm
JTMD Species Vector Distribution
0
1-2
3-4
6-9
15
16 - 17
The map below shows the number of species that were introduced to each realm via natural
dispersal. The most prevalent regions are Temperate Northern Atlantic, and Temperate
Northern Pacific.
Natural Dispersal JTMD Species Vector Distribution
Species / realm
0
1
2
3
5
7
The map below shows the number of species that were introduced to each realm through
moveable structures. The most prevalent regions are Temperate Northern Pacific, and Southern
Australia/ New Zealand.
Moveable Structures
JTMD Species Vector Distribution
Species / realm
0
1
2
3-4
The map below shows the number of species that were introduced to each realm through
Recreation. The most prevalent regions are Temperate Northern Atlantic, along with Southern
Australia/ New Zealand.
Recreation
Species / realm
0
1
2-3
4
5
JTMD Species Vector Distribution
The map below shows the number of species that were introduced to each realm through
Aquaculture and Fisheries trade. The most prevalent region for this vector is Southern
Australia/ New Zealand.
Solid Ballast
JTMD Species Vector Distribution
Species / realm
0
1
2
4
5. Critique of the method - what was useful, what was not? This is a largely visual
interpretation of the data, without using statistical analyses of the data. However, it is
very useful to be able to visualize the different methods of transport spatially on a map
of the geographic regions, and be able to see the different number of JTMD species
introduced to each realm by each vector. These maps are also useful to visualize high
and low frequencies of transport occurrence – the maps seem to show a preference for
certain regions in frequency . It is a nice visualization of the JTMD species spatial
dimensions of vector dispersal.