Case study of ecosystem health
LAND 6401 Cora Lawton 1176872
Landuse Patch-corridor-matrix Connectivity Ecological Health
5 6 7 8
1. Field Trip 1 2. Field Trip 2 3. Field Trip 3 4. Patch I.D. Map 5. Pest Health Map 6. District Plan Map 7. District Plan Health Map 8. Core-patch Ratio Map 9. Core-patch Ratio Health Map 10. Quality of Matrix Health Map 11. Connection Attribute Table 12. Eco Health Attribute Table
12 16 20 25 26 27 28 29 30 31 32 33
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Introduction New Zealand’s natural environment has changed enormously in a short time and has become very provide habitat for some species and create dispersal opportunities. Many species don’t require corridors for disfragmented and deforested through human settlement and it is through landscape ecology we can study the persal, but as New Zealand is a nation full of birds corridors are an important part of our landscape ecology as they health of our landscape by studying the effect landscape patterns have on processes across a range of spatial provide connections for them. (Forman, 1995) and temporal scales within the heterogeneous landscape. Patterns and processes at a large scale are used to Grain “understand the interplay between the natural and human factors that influence the development, and the imGrain is reffered to as the spatial proportion of the landscape and is measured by the coarseness of elepacts of landscape patterns on humans, other organisms, and the flows of materials and energy among patch- ments within that area. It is determined by the sizes of the patches that are distinuishable in the landscape. A es” (McGraw-Hill, 2011). Patterns in the landscape are studied by assessing the patches, corridors and matrix, fine grained landscape is one many small patches, whilst a coarsed grained landscape is comprised of mainly larger they are not only a result of human activities but also disturbance and succession. It is through these patterns patches. we begin to read and define the landscape and develop methods/strategies to preserve and/or enhance connections within the wider landscape that continues to be fragmented. The landscape ecology patch-corridor-matrix model was used to determine the health of our study area in Riverhead/ Mosiac Coatesville/Albany and the Northshore. From an aeroplane the landscape appears as a mosiac full of patterns. Patterns are found all over the landscape as tiny granules with diffeternt colours and grains. These patterns are found in all spatial scales and they form a pattern of patches, corridors and matrix. Based on the Janssen theory ideigenous forests, broadleaf indigenous hardwoods, manuka and kanuka shrubland deciduous hardwoods, mixed exotic shrubland and other exotic forest became our patches and corridors (depending on their size). Pastoral blocks, ochards, hedges and forestry became our matrix. (Forman, 1995).
Heterogeniety The land is heterogeneous landscape full of elements like agricultural fields, blocks of forest, housing subdivisions etc that interact with each other. Heterogeneity not only applies to the spacial patterns in the landscape, it also applies to the “vertical structural complexity” (pg. 146, Lindemayer & Fischer, 2006), the height differences over the area. Heterogeneity occurs in the landscape in two ways, as a gradient or a series of gradients that have variation over space in the objects present and it has no boundaries. The gradient is measured by the difference in contrast between patches and the matrix i.e. a indegeniuos forest next to a pastoral farm has a higher gradient than a idigenous forest to to a forestry block. (Forman, 1995).
Matrix The matrix is the background (larger landscape) that has many important roles within landscape ecology. It can for example “...affect the population dynamics of individual species, including population recovery after disturbance, the exchange of individuals between patches and occupancy rates of vegetation patches” (Lindemayer et al, 2006).
Patch A patch is an area or gap in the landscape created after fragmentation and is relatively homogeneous (has the same vegetation) and they are different from their surroundings. Patches are for ever changing and fluctuating (a process called patch dynamics). All patches must contain a core, in a way it is like the heart of the patch, it provides a structually complex area that supports a lot of species. In this study we based our patch sizes on the Janssen, 2006, Bush Vitality Assessment: growing common futures model. Large patches were 25 hectares or more, whilst small ones were 5 to 25 hectares. Patches benefit the landscape by providing a core habitat, they support more species and “sustain viable populations of many interior species” (pg. 271, Forman, 2008). The core is the inside area of the patch e.g. a circular 5 hectare patch will have a core of 1 hectare. The core of these patches are rarely influenced by the matrix, unlike the edges. Edges are the outside area of patches that are often effected by the it’s surroundings i.e. the matrix, humans, the environmental conditions like weather and their environments are different from the core. In turn the edges have soils, plants and animals that differ from the core and can handle the tougher environments the edge provides. (Forman, 1995).
Corridors Corridors are all edge (do not contain a core), and differ from the surrounding landscape either side of them. They can be easily influenced by the surrounding matrix but they also provide connections between patches allowing organisms to move freely through the landscape. They also create barriers between species,
Method To determine the ecological health of the study area (Riverhead through to Northshore), field trips were made to suitable parts of the region, providing field data for our area (these can be seen in the Appendix 1-3). The remainder of the report was created by producing maps to measure the landscape ecology of our study area. These maps wer created with a GIS programme. The first map produced was the land use map. This was done by accessing the data from the LCDB2 layer in GIS and expanding out the landuse patterns over the landscape. The second map was the patch-corridor-matrix map this was produced by utilising the LCDB2 layer and extracting information from it. To complete this map I did the following: - Identified indigenous forest, broadleaf indigenous hardwoods, manuka and kanuka shrubland, deciduous hardwoods, mixed exotic shrubland and other exotic forest. - Made the selected areas of the landscape into patches of vegetation. - The patches were then divided into their categories corridors, small patches and large patches. - Large patches were defined by the size of the vegetation patch. The area contained a core and exceeded 25 hectares. - Small patches also contained a core and were between 5 and 25 hectares. - Corridors were all the remaining patches that did not contain a core. - The matrix remained in the background to show the contrast between it, the corridors and the patches. After this the third map was completed. This is the connectivity map and it was created by assessing the number of large and small patches within a 2, 5 and 10km distance. This was applied to both small and large patches. Each patch was assessed by the bush visual assessment table by Janssen. It was as follows:
The outcome results for each large patch was as follows (the full attribute table can be seen in the Appendix 10):
The forth map is the Ecological Health map. To complete this map I choose 5 aspects that effect the health of every large patch in order to determine just how healthy the large patches are in the study area. The five aspects I selected were pest control, district plan zones, patch-core ratio, matrix and connectivity. The reason for their selection was: Pest Control: Pests have a huge impact on the health of landscape ecology, they take food supplies away from our native species (especially our birds), they have a large impact on our native vegetation i.e. nectar robbers, taking the nectar from puriri flowers, preventing native birds from pollinating the flowers (see Appendix 2) or possums destroying the foliage cover in indigenous forests. District plan zones: The district plans have a huge role in protecting and enhancing and native and exotic forests. Each council has regulations for protection of natural features which are more dominant in reserves, rural and country side living areas. This means it is more likely the patches are protected in these areas, but it lacks in other areas like residential and this creates poor connectivity for the landscape. Patch-core ratio: If a patch has a large core it is structurally complex. This makes the patch more resilient and able it is to cope with the negative effects of change in the landscape. They also support more species than smaller patches and corridors and â€œprovide core habitat for species that depend on native vegetationâ€? (pg. 197, Antrop, 2005). Matrix: The matrix is the background of landscape ecology and provides connections to corridors and patches. A matrix with fewer open patches (i.e. farming land) will have stronger connections with patches. A heterogeneous matrix allows for more species to move through it and if it has a gradual gradient and is not patchy the species movement is easier. It is a key factor for species movement between native patches (Forman, 2006). Connectivity: The evolution of most species was when the landscape was a highly connected heterogeneous one and they have had little time to adjust to the fragmented landscape it is today. Species occur in greater numbers in a well connected landscape (Foreman, 2006). Table retrieved from: pg.178, Janssen, H., 2006.
Criterias were then created to determine the scale of the health for the large patches and scored as per the conditions stated. The tables are as follows:
This Quality of Matrix map was scored based upon the matrix surrounding the large patches (Map in Appendix 9).
This pest map was created by studying the district plan and assessing the control of pests as per land ownership (for Map see Appendix 5).
The connection aspect was based upon the same criteria as the bush vitality bush assessment but it was broken down into a score of 5. The district plan aspect was scored by studying the objectives and policies of zones in the district plan from local councils (Rodney and Northshore retrieved from their web sites www.rodney.govt.nz and www.northshorecity.govt.nz. For district plan see Appendix 6).
The Ecological health map was then created by giving the patches adding up all the aspect scores and giving them an overall score out of 25 (as seen in Appendix 11). The score criteria was as below.
The core-patch ratio map was scored based on the overall dimension of the large patches and their cores and getting a percentage of core coverage within in the patch (Map in Appendix 9).
The data collected for this report was very limited. Full access to scientific
reserch and data was unavailble and we were very limited to the field research we could gather from the few site visits we did make. Assumptions have been made but have been backed up by theory provided from suitable sources i.e. books and GIS data
Map 1: Landuse
Ăœ Legend Land-use Map Key Afforestation (imaged, post LCDB 1) Alpine Gravel and Rock Broadleaved Indigenous Hardwoods Built-up Area Coastal Sand and Gravel Deciduous Hardwoods Dump Estuarine Open Water Forest Harvested Gorse and Broom Indigenous Forest Lake and Pond Low Producing Grassland Major Shelterbelts Mangrove Manuka and or Kanuka Mixed Exotic Shrubland Orchard and Other Perennial Crops Other Exotic Forest Pine Forest - Closed Canopy Pine Forest - Open Canopy Short-rotation Cropland Transport Infrastructure Urban Parkland/ Open Space Vineyard
Map 2: Patch-corridor-matrix
Ăœ Legend Connectivity Map Category Corridor Large Small
Land cover matrix LCDB2NAME Afforestation (imaged, post LCDB 1) Alpine Gravel and Rock Broadleaved Indigenous Hardwoods Built-up Area Coastal Sand and Gravel Deciduous Hardwoods Dump Estuarine Open Water Forest Harvested Gorse and Broom Indigenous Forest Lake and Pond Low Producing Grassland Major Shelterbelts Mangrove Manuka and or Kanuka Mixed Exotic Shrubland Orchard and Other Perennial Crops Other Exotic Forest Pine Forest - Closed Canopy Pine Forest - Open Canopy Short-rotation Cropland Transport Infrastructure Urban Parkland/ Open Space Vineyard
Map 3: Connectivity Map
Legend Connectivity Map Health Excellent Fair Good
Map 4: Ecological Health Map
Legend Large Patches
Ecological Health Excellent Fair Good 1:55,000
Findings Map 1 The land use map shows how the land is used within our study area. The south east area of the site is mainly developed, with pine forest and low producing grassland dominating to the west. There are a few smaller areas of indigenous forest mixed with deciduous hardwoods. You can clearly see from this map the
contrast between the urban, rural and forest categories. The urban areas has very little patches of vegetation, whilst the rural contains more that provide connections to the forest but it is still dominated by grazing land. It also shows that the study area is a heterogeneous landscape.
Map 2 This patch-corridor-matrix map shows the relationship of large patches, small patches, corridors and the matrix. The matrix is very vast and the west region of the map lacks large patches, the majority of large patches is through the centre of the site. This has created quite a connected landscape through the middle, but it looks quite disconnected on the outsides. The biggest patch in the area is nearly 478 hectares with the
average large patch size being 25-100 hectares. The smaller patches range in size from 5-25 acres and the average small patch size is 5-15 hectares. This tells me that the larger patches vary in size, with a majority of them being between 25 and 100 hectares, which is quite a size difference and there is one dominant large patch. There is also quite a few significant sized corridors.
Map 3 The connectivity map shows the larger of the patches have excellent connectivity with the surrounding patches. There are a few smaller patches that have a lower connectivity rating than the rest. A few patches to the northwest are quite a distant from the larger patches, but are there are quite a few small patches within this area so habitat isolation would be minimal, and species would be able to move freely within this area and create viable populations. There is one particular patch in the northwest that is classed as
fair however it is right next to a forest that provides excellent connectivity, especially for rengeration of understory native plants. Although the connection according to this map is excellent the heterogeneous matrix and corridors create many more opportunities for species movement through the study area and allows for smaller areas of habitat for smaller populations.
Map 4 The ecological health maps combines a range of aspects and shows that the large patches in study area is of quite good health. I think it is important however to enhance the health of the biggest patch as a lot of the other smaller patches in the area could be quite reliant on it to maintain their health and enhancing this
patchâ€™s health would have a positive effect on the surrounding patches (providing the connections remain strong). To retain the health of this landscape and prevent it from declining anymore it is important that procedures be put in place to control or maintain it to a standard that is not any less than what has been assessed in report.
Discussion The findings in the maps show that the area is well connected, but the larger patches do lack a bit in health. To prevent our landscape health from deteriorating it is important changes be made to the way we utilise our landscape. Patches are an important element and there are many types of patches in landscape ecology, these include disturbance patches, they are a result of an alteration or disturbance in a small area; a remnant patch appears when a small area escapes the disturbance around it; an environmental patch too me is one of the most important patches as they are natural and change slowly over time and are stable; a disturbed patch is one that changes rapidly is continuously disturbed (by ploughing with tractors etc) to itâ€™s maintained state, but if left they could regenerate. Environmental large patches are an important element in New Zealandâ€™s landscape as they provide and sustain viable species populations that smaller patches and corridors are reliant on. A subdivided large patch (can been seen in patch core ratio map in Appendix 8) will contain a smaller corepatch ratio, this creates a larger edge effect on the patch and a result of this is higher rates of edge species and smaller populations of interior species. A good example of a patch with a subdivision would be the number eight. The inner centres of the circles at both ends would be the cores and the remainder of the shape would be the edge. (Forman, 2008). According to Jassen patches greater than 25 hectares are large enough to sustain populations of key native species and ecosystem functions (provided the pests are controlled). Within the larger patches key native emergent plants are evident. These include kahikatea, rimu, miro, totara, pukatea, rewarewa and rata. Examples of these emergent species were evident in the interior of the forest on our field trip to Poremoremo Reserve in Albany (see Appendix 1). The interior of this forest was more of a gully that provided the perfect conditions for these plants to thrive in, this demonstrates that the environmental conditions for the core or interior have to be right for these plants to grow. These plants prefer a richer soil which is generally located in the gullies of forests as they collect all the water and nutrient run off from surrounding areas. As these plants are an important source of food and shelter for our native birds year round it is vital that viable populations of them remain in our landscape and as these are interior species it is imperative that healthy large cores are sustained. These plants are dispersed in different ways (wind, birds or pollination by birds) so connections with the wider area is fundamental to their survival. (Janssen, 2006) Canopy and sub canopy plants are also important in patches. They are exposed to the elements like emergent species and they protect the lower canopies. The plants range in size from 5-30m and are more shade tolerant. Good examples of these plants are nikaus, kohekohe, toro and pigeonwood. These plants were evident on our field trips in the interior of the forests (as seen in field trip data in Appendix 1, 2 and 3). Native birds rely on these for nesting and providing their young with food. (Janssen, 2004). The under storey planting of native patches provide a variety of shade loving plants including ferns and juvenile plants. These are important as they provide seed banks for future generations and are a key food source for native birds. (Janssen, 2006). A minimum core of 1 hectare can provide a seasonal breeding habitat and stepping stone for connecting isolated bird populations. It is important that these smaller patches are with in a close distance of larger viable patches to prevent interbreeding that will cause genetic deficiencies and increase the chance of local extinction (Forman, 2008). A landscape with considerable amounts of corridors and stepping stones provides a strong connection for species that are unable to move through the matrix and they also provide additional area for native species (Lindemayer et al, 2006). Another factor in connecting the landscape is the matrix. A strong matrix creates habitats for many species through out the landscape and provides connectivity between patches. It is important however the gradient in the matrix is gradual not hugely effecting the edge effect of patches. An example of this would be our field trip to Riverhead where we observed a low gradient landscape, the transition from one area to the other was gradual providing a supportive landscape for the forest landscape. (Lindemayer et al, 2006). It is eminent that the connectivity between the landscape is retained to provide pollen and seed interchange, mating options and good food source availability. Bush patches in New Zealand within 2km of each
other are likely to have native birds flying between them, this provides them with a wider range of food sources and allows them to distribute native plants more effectively throughout the area. Connections are also important for our native birds in breeding seasons to sustain local viable populations. Forest patches 5km or more away are less likely to be accessed by smaller native birds. (Janssen, 2006). Pest species also have an impact on the health of our native patches. Possums are one of our most persistent pests, they eat leaves, shoots, flowers and fruit off our plants removing important food sources from our native birds. They are also a threat to native insects and nesting birds. Possums are not the only animal that threatens the health of our landscape ecology, other animals include pigs, goats, horses, stock, stoats, weasels, ferrets, cats and dogs. These animals are linked to killing not only our native birds but also young trees depleting the diversity of the forest so when older trees die there are fewer trees left to regenerate. Pest traps were evident on our field trips to public reserves, this showed local authorities do have procedures in place for pest control. Plant pests are also a problem, competing for the resources native plants need to survive like sunlight. (Janssen, 2006). In order to retain a well connected landscape within our study area it is important that all of these issues are addressed and changes are made to how we fragment the landscape without considering the landscape ecology.
Conclusion New Zealand has a remarkable landscape that relies highly on our native birds and to retain a healthy landscape in our study area I propose that the connectivity and large patches be retained. It is eminant that the landscape will be broken up even more, but it is vital that the connections within the corridors and matrix are and retained to provide connections for the birds. This can be achieved by protecting existing corridors and planting more compatible exotic species within the matrix. These plants include oak, beech, walnut, apples and plums as they not only help with the connection within the landscape but they also serve as a decoy for possums and other pests who eat on them instead of our native plants. Compatible exotic species can also be a part of succession towards native bush and are useful as buffers against exotic plant pests. Compatible tree crops can also be planted to provide shade for regenerating shade loving natives. (Janssen, 2006). If it is imparative that a corridor be removed for development, actions need to be put in place to replicate the corridor in another area or suitable vegetation is planted within the developed area. This will create less of an impact on the connections and provide alternative solutions for the birds that visit the area frequently before the development. Habitat loss is a key factor in biodiversity decline in New Zealand. If an ecosystem lost more than 80% of itâ€™s vegetation cover sustainability is breached. New Zealand has a 22% native vegetation cover and this is undesirably close to 20%. If native threshold is breached then the biodiversity declines and the irreplaceable native diversity becomes invaluable. This is why we need to retain the connections within our landscape. (Janssen, 2006) As a healthy native bush patch requires at least 20% emergent species visible above canopy it is important that all the larger patches in the area are retained to provide native birds with these emergent species for food and shelter. Native animals keep our bush healthy by distributing and pollinating native plant species. Native species are now under threat due to the continued fragmentation and disruption of their habitats. Our native bush adapted itself to support to them and they are important in maintain viable populations of vegetation. An approach to protecting our cores would be to concentrate recreational use of patches to the edges, this is an efficient way to protect the interior. Another example would be to stop creating road routes through the cores of patches and restrict road development to the edges of patches. (Forman, 2008 & Janssen, 2006) Our economy and society rely strongly on the ecosystem services provided by native ecosystems and at the moment 30% of bush in New Zealand is privately owned or is a local authority reserve. This means it is essential local authorities to put procedures in place that will protect and/or enhance our landscape ecology. (Janssen, 2006) The short term focus to protecting our landscape ecology would be to mitigate and action pest control especially on privately owned sections as they seem to lack in pest control. This can be achieved by local authorities educating the community and enforcing the positive outcomes on our environment pest control will have. In the not to far future integrated sustainable farm production and bush protection could be put in place. This will address bush patch size and connectivity. As corridors are smaller than large patches, they are easier to maintain. This means a good place to start in creating a better connected landscape would be the corridors. (Janssen, 2006) In the long term it would be good to establish sustainable productive farming of compatible species integrated in resilient native ecosystems. The native vegetation will be significantly greater and will restore bush vitality and maintain native biodiversity. (Janssen, H., 2006) It seems inevitable that our landscape will be fragmented even further, as new housing and developments will be needed to sustain our human population, but it is vital that we try our absolute hardest to do this without disconnecting our landscape ecology even further and this could be achieved by implementing these procedures.
Appendix 1: Field Trip 1
Appendix 2: Field Trip 2
Appendix 3: Field Trip 3
Appendix 4: Large patch I.D Legend Patch I.D
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Appendix 5: Pest Map
Legend Pest Control 1 2 3 4 5 1:60,000
Appendix 6: District Plans
Northshore City District Key
Rodney District Key
Appendix 7: District Health Map
Legend District Plan 4 5 1:60,000
Appendix 8: Core-patch Ratio Map
Legend Core-Patch ratio Large patches Core
Appendix 8: Core-patch Ratio Health Map
Legend Core Patch Ratio 0 1 2 3 4 5 1:60,000
Appendix 9: Quality of Matrix Health Map
Legend Matrix Health 2 3 4 5 1:60,000
Appendix 8: Connectivity Attribute Table Patch Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small Small
2km 6 5 3 6 3 3 5 3 6 6 6 5 5 5 5 5 3 3 6 6 6 6 6 6 6 5 5 5 5 5 6 6 3 6 6 6 6 5 6 6 6 6 6 6 5 5 6 6 6
5km 5 5 3 5 5 5 5 5 5 3 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 3 5 5 5 5
10km 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
Total 14 13 9 14 11 11 13 11 11 12 14 13 13 13 13 13 11 11 14 14 14 14 14 14 14 13 13 13 13 13 14 14 11 14 14 14 14 13 14 14 14 14 14 14 11 13 14 14 14
Health Excellent Excellent Good Excellent Good Good Excellent Good Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Good Good Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Good Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Good Excellent Excellent Excellent Excellent
Small Large Large Large Large Large Large Large Large Large Large Large Large Large Large Large Large Large Large Large
5 3 5 6 6 6 6 3 6 6 6 5 6 5 5 6 6 6 6 3
5 2 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
13 8 13 14 14 14 14 11 14 14 14 13 14 13 13 14 14 14 14 11
Excellent Fair Excellent Excellent Excellent Excellent Excellent Good Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Excellent Good
Appendix 8: Eco Health Attribute Table
Large patch no. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Core-patch 4 4 3 3 2 1 5 4 0 4 1 3 2 2 1 2 5 1 5
District plan 4 5 4 4 4 4 5 4 4 5 4 4 5 4 4 4 4 4 4
Pest 1 1 1 1 1 1 5 2 3 5 1 3 4 2 1 1 2 1 2
Connection 3 5 5 5 5 5 4 5 5 5 5 5 5 5 5 5 5 4 5
Matrix 5 2 3 2 3 4 5 3 3 2 3 3 3 2 2 3 3 4 5
Total out of 25 17 17 16 15 15 15 24 18 15 21 14 18 19 15 13 15 19 14 19
Health class Good Good Good Fair Fair Fair Excellent Good Fair Excellent Fair Good Good Fair Fair Fair Good Fair Good
References Antrop, M. (2005). From holistic landscape synthesis to transdisciplinary landscape management. In Tress, B., Tress, g., Opham, P (Eds). From Landscape Research to Landscape Planning: aspects of integration, education and application (pp27-50) Forman, RTT. (1995). Lanscape mosiacs the ecology of landscapes and regions. United Kingdom: Cambridge University Forman, RTT. (2008). Urban regions: ecology and planning beyound the city. United Kingdom: Cambridge University Haines, L. (2011). Landscape Ecology Handbook. Auckland: Unitec Copy Centre Janssen, H. (2006). Bush Vitality Assessment. Christchurch: Rainbow Print Ltd Lindenmayer, DB., & Hall GMJ. (2006). Habitat Fragmentation and Landscape Change: an ecological and conservation sythesis. McGraw-Hill. (2011). Landscape Ecology. Retrieved April 10, 2011 from: www.answers.com Northshore City Council. (2011). District Plan. Retrieved April 24, 2011 from: www.northsorecity.govt.nz Rodney District Council. (2011). District Plan. Retrieved April 24, 2011 from: www.rodney.govt.nz