**3. Land use management strategies for addressing mangrove ecosystem degradation at Mon Repos**

The focus of this section of the study is to examine the ways in which the application of zoning and regionalization can contribute the sustainability of the mangrove ecosystem at Mon Repos, Guyana.

#### **3.1 Location and site selection criteria**

The study area, Mon Repos, is located on the 1,803,312 ha Coastal Plain which is a narrow strip of land adjacent the Atlantic Ocean or on the north-eastern coast of Guyana, South America and in the Demerara-Mahaica Administrative Region/ Region 4 (**Figure 2**). Its Geographical coordinates are 6.8064° N Latitude and 58.0523° W Longitude, and it is found approximately 17 km from the capital city of Georgetown. Mon Repos is bounded to the west and east by the villages of Triumph and Goed Hope respectively and to the north by the Atlantic Ocean. It extends for about 5 km inland (southward) from the coast.

The study area is part of the coast which experiences wave height above 3.5 m only about 2% of the time when unusually high spring tides occur; 2 m from December to June and 1–1.5 m from July to November. Wave energy is therefore considerably reduced on the coast because of the continental shelf that stretches for an average distance of 140 km. Similar to other areas along the coast, Mon Repos is influenced by tropical climatic conditions with two wet (May–August and December–January) and two dry seasons (February–April and September–November) experienced annually. Annual rainfall averages 2200 millimeters (mm) with an average of 200 coastal rain days annually. Humidity is high all year round, and there is a narrow range of temperature (26–28°C) [37].

The northeast trade winds affect the area with an average wind speed of 12.2 kilometers per hour (kph). The coast accommodates unique ecological niches and habitats for a variety of marine and terrestrial animals, and it is at risk of inundation due to sea level rise. Its level of vulnerability increases following projections of sea level rise for the country of as much as 0.88 m by the end of the century [37]. Increases in storm surges of about 5 m are expected to affect more than 22,000 hectares of the

#### **Figure 2.**

*Location of the study area, Mon Repos. Source: Compiled by the Author.*

coastal zone, leading to further inundation and erosion [37, 17]. Mangroves function as natural breakwaters along the coast and represent an important natural sea defense for Guyana [46, 47].

Soils found there originated from different types of parent materials, but they are predominantly impervious clays and pegasse soils (fluvio-marine deposits) which become inundated during high tides. Despite the presence of an elaborate drainage network and mechanical drainage facilities, the area floods from heavy and continuous rainfall. The area is protected by a portion of the 69 km of masonry sea walls and the 78 km of sand banks which exist along the coast, and several hectares of mangroves as well. No marked change in land use has been identified over the past decade, except the expansion of residential and light commercial zones and mangrove proliferation naturally (**Figure 3a** and **b**).

Four criteria were used in the selection of the study site for data collection. These are:

i.Ecological consideration: the need to identify a site where mangroves have colonized naturally and profusely so that research on the conditions could be considered for replicability; and

*Perspectives and Application of Land Use Management Strategies to Address Mangrove… DOI: http://dx.doi.org/10.5772/intechopen.112752*

#### **Figure 3.**

*(a and b) Main Land uses identified at the study area. Note: Google Earth Images, June 2023. Source: Compiled by the Author.*


#### **3.2 Data collection, procedure and process**

Landsat TM image was used to locate and measure the mangrove area at Mon Repos in 2013 and 2022, then land use classifications were identified considering important spatial criteria for better planning and scientific management of the mangrove ecosystem. Mangrove cover and land-use maps were created using ArcGIS Pro and Landsat images. Landsat imagery covering the study area was downloaded from the USGS Earth Explorer and ancillary data were gathered from additional datasets such as digital elevation models (DEMs) and existing land-use maps. Radiometric calibration was done to the downloaded Landsat images to convert digital numbers to reflectance values using appropriate band-specific calibration coefficients with Landsat 8 OLI/TIRS Sensor: Band 4 (Red): Calibration coefficient = 2.0000; Band 5 (Near-Infrared): Calibration coefficient = 1.2500; Landsat 7 ETM+ Sensor: Band 3 (Red): Calibration coefficient = 2.0000 and Band 4 (Near-Infrared): Calibration coefficient = 1.2500. Correction was also done to remove atmospheric effects.

For mangrove mapping, Supervised Image Classification techniques were applied to the preprocessed Landsat images in ArcGIS Pro. This involved assigning different land cover classes to the pixels based on their spectral characteristics. An accuracy

assessment of the matrix was done to validate the accuracy of the classified image by comparing a representative sample of classified pixels with ground truth data.

The mangrove cover map and ancillary data on existing land use were used to create a comprehensive land-use map for the two years. This involved digitizing and classifying different land-use types. To validate the land-use map, images (pictures) of the area were used as reference.

#### **3.3 Zoning, regionalization and Mangrove ecosystem degradation at Mon Repos**

Attempts have been made in the past to allocate specific sections of the community to specific uses. Over the years, Mon Repos has benefited from basic infrastructure upgrading, facilitating a thriving market, commercial banks, super marts, and small businesses. The surrounding land uses recognized from the mapping exercise are residential, commercial and infrastructure (roads and seawalls). These social and economic units are in proximity to the mangroves as shown in **Figure 3**. Population growth in the community has led to encroachment on and removal of mangroves especially along the south-western section of the mangrove areas. It is wellestablished that any adverse land use in proximity to mangroves could lead to their destruction thereby affecting the ecosystem as well as the integrity of the coastline in that location.

The study revealed that approximately 53.0 hectares of apparently healthy mangroves existed at Mon Repos as of June 2023. This figure represents 11 times the number of hectares of mangroves when compared to 4.7 hectares in 2013 (**Figure 4**). This is a relatively significant amount of mangrove cover, given the size of the community. The significant difference in changes in mangroves between the two years highlight the relevance of more detailed and local studies to understand the processes

#### **Figure 4.**

*Mangrove Coverage in 2023 and 2013 . Note. Images created from ArcGIS Pro. Landsat images, digital elevation models (DEMs) and existing land-use maps. Source: Compiled by the Author.*

### *Perspectives and Application of Land Use Management Strategies to Address Mangrove… DOI: http://dx.doi.org/10.5772/intechopen.112752*

leading to the proliferation of the vegetation despite encroachment and removal of the vegetation in some sections.

The risk of conflicts at the community level, particularly because of the population encroachment on the south-western periphery of the mangrove site and potential mangrove conservation efforts, can be addressed by establishing functional zones in which zoning control mechanisms are applied for optimal coastal land and ecosystem utilization. In zoning this area, two aspects ought to be considered. These are the quantity to be assigned for different land-use activities and how to allocate different amounts of land use in the space available (spatial allocation). This can be achieved by using a framework of land-use suitability evaluation and a cell-based approach to allocate residential, commercial, infrastructure and wetland (mangrove) land uses in land-use spatial zones (LUSZ) or functional zones at Mon Repos. In this case, land suitability maps become necessary to guide all land use decisions. If this is avoided, the result could be viewed as a spatial optimization problem.

While the study area has fostered mangrove colonization over the years, contiguity and compatibility of land-uses appeared to be an issue. For instance, huge volumes of solid waste (both biodegradable and non-biodegraded) were observed in the mangrove stands (**Figure 5**). Here the applications of GIS and RS are relevant and suitable decision-support tools for monitoring of the mangrove site. This is likely to solve the spatial optimization problem at the study area and prevent degradation of the ecosystem there. The study showed that RS with a high spatial resolution can assist with the (a) acquisition of information at relatively small spatial scales such as Mon Repos and (b) production of repeated measurements for the site.

Regionalization was performed based on land-use in and around the study site and its potential (recreational, tourism) and ecological service (forest utilization, material production, faunal habitats) interpreted from the Landsat images. These were analyzed in accordance with the integrity of the ecosystem status quo. As it

#### **Figure 5**

*Mangroves and Domestic and Industrial Effluents at the Study Site, May 2023. Note: Picture was obtained from the National Mangrove Restoration Project, NAREI, Guyana.*

relates to proximity, the mangrove ecosystem was found to be surrounded by three natural functional units, which are marine ecosystem, offshore tidal flat, and estuary/ocean waters.

It appeared that the mangrove ecosystem has not been under the control of subregion/Neighborhood Democratic Council (NDC) or the Mangrove Project Unit at NAREI. This could have been one reason for encroachment of the site, destruction of the mangroves and solid waste disposal issue. Having the site under subregional control could result in a high-density mangrove stand, better application of management strategies, control of waste pollution, and encourage community participation. A caveat though is that while having mangroves under sub-regional protection is an idealistic approach, it could be counter intuitive since the lack of updated zoning regulations and standards and enforcement of outdated ones could result in governance issues and conflicts over mangrove ecosystem use. There are other factors that need to be considered too. These include limited coordinated effort among relevant agencies to maximize benefits from the application of regionalization, limited technical skills to collect and analyze scientific data using GIS and RS technologies.
