Land Use Land Cover Changes and its Implication on the conservation of Re-introduced Kihansi Spay Toads (Nectophrynoides asperginis) in Kihansi Gorge-Tanzania

Land use land cover change (LULCC) is a global threat to biodiversity conservation. Endemic species such as Kihansi spray toads (KST) are prone to extinction due to LULCC. This study assessed the LULCC of the Kihansi catchment (KC), a potential habitat for the KST and adjacent areas. Remote sensing (RS), geographical information system (GIS) and 156 questionnaires administered to three surrounding villages namely: Mgugwe, Udagaji and Ukami were used to assess the LULCC forms in the study area. Landsat imagery and ground truthing, were used to classify and monitor LULCC for 25 years from 1995 to 2020. Results


Introduction
Biodiversity hot spot areas host global potential for the conservation of wildlife species particularly those that are endemic and critically endangered like the KST (Lindenmayer, 2019). Land use land cover changes (LULCC) contribute to the extreme loss and extinction of endemic, rare and endangered biodiversity species such as the Kihansi spray toads (KST). Human activities such as infrastructure development and agriculture support LULCC and threaten species through habitat loss, fragmentation, and destruction (Mmbaga et al., 2017;Franco-Belussi, et al., 2020). It has also been reported that human induced LULCC triggers ecological changes that lead to a decrease in biodiversity and increased species . During its discovery (before dam construction in 1996) the KST was estimated at 20,000) individuals (Nahonyo, 2019). Due to habitat dryness in uenced by water diversion after dam construction the number of toads decreased (Rija, et al., 2011). Arti cial sprinklers were made to mimic the natural spray leading to an increase in number of toads in 2001 (Nahonyo, 2019; Rija, et al., 2011). A sudden decrease in toad numbers occurred again between 2003 and 2004; hence there was no heard or sighted toad in their habitat. This led to their extinction in the wild declaration in 2009 (Nahonyo, 2019). It is believed that, Kihansi dam construction resulted in alteration of biodiversity habitats thus resulting in the extinction of the KST in the wild (Rija et al., 2011). The habitat has been restored and the KST has been re-introduced.
However, little is known about LULCC taking place in the area which could have impacts on the survival of KST apart from dam construction which is also important in the alteration of biodiversity. In this case, understanding the extent to which LULCC is taking place in the Kihansi ecosystem is essential for the sustainable conservation of biodiversity including the re-introduced KST.
In this study we focused on assessing the extent to which LULCC has taken place in the Kihansi ecosystem for the last 25 years from 1995 to 2020. Additionally, the opinions of local communities on LULCC were inquired from the respondents adjacent to the Kihansi Catchment habitat for the KST. This study is essential for the sustainable conservation of the re-introduced KST and wildlife species.

Image acquisition, processing and analysis
The area under the study were identi ed, demarcated and different categories of LULC were classi ed using Google earth Pro as suggested by Ngongolo, Estes, Hudson, & Gwakisa (2019). The area was monitored for the last 25 years from 1995-2020. Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) imagery were used to analyze land cover change of the years1995, 2004 and 2020, respectively. The aim of choosing these years was to compare the LULC of the KC and its adjacent areas before dam construction (1995), after dam construction (2004) and after restoration and reintroduction of the toads (2020). The Kihansi catchment area extends within a single Landsat path and row. High resolution satellite imagery (30m spatial resolution) was used to download images from the US Geological Survey (USGS) Earth Explorer (http://earthexplorer.usgs.gov). The images were selected based on season (dry season) as previously suggested by (Mmbaga et al., 2017) because during the dry season, it was possible to identify forested land and the remaining bare lands were considered agricultural lands. All images (1995,2004 and 2020) were obtained within the same time of the year (ranging between June 23 and August 14) ( Table 1). Shape les for study site boundaries were obtained from The National Bureau of Statistics (NBS) available at (https://openmicrodata.worldpress.com). Satellite images of different years were imported into ArcGIS (version 10.3) for processing and analysis. The geographic coordinate system was de ned as the World Geographical System (WGS) 1984 and projected to the Universal Transverse Mercator (UTM) Zone 37S prior to analysis. Image processing and analysis included image clipping and composite bands formation. In this study, natural colour bands were used. Three Landsat images were classi ed by using the maximum likelihood function, which is the most common decision rule among the supervised classi cation (Mmbaga et al., 2017). It is also considered to give very accurate results because each pixel is assigned to the class to which it has a highest probability of belonging (Mmbaga et al., 2017) Visual interpretation and digital image classi cation were then combined using GIS functions.
Three land use classes de ned in the study area were: (1) agricultural land (seasonal cultivated lands, bush lands, bare lands open areas, grasslands, and livestock grazing); (2) forested land (3) Settlement (any type of buildings). Training sites were determined and signature les were created to be used in the classi cations by using ArcGIS (version 10.3). After that, the classi ed images were compared with ground truthing ( eld visit) that was achieved with the assistance from Kihansi management team members to validate the collected information and modi ed accordingly. Additionally, to improve the accuracy on the past images of the years 1995, 2004, and 2020 interviews with local people were conducted. To improve and analyze the data at a better quality scale, the LULC classi cation and analysis were done across the three villages: Udagaji, Mgugwe and Ukami.
2.3. Data collected on Land use land covers changes through questionnaire survey from local communities adjacent the Kihansi area.
The interviews involved 156 respondents from the three study villages (Udagaji, Mgugwe and Ukami). Extensive eld observations and interviews were conducted by administering a structured questionnaire to respondents aged 45 years and above, who had lived in the respective location for at least 25 years from the age of self-awareness (15years). The information captured through the questionnaire was as follows: awareness of respondents on land use types of KC and adjacent areas in relation to KST conservation within the range of 1995 to 2021. In addition, the socio-economic activities of local communities and the trends of different land use types over the past 25 years were captured. In addition, reasons that could promote changes in land use and cover were addressed in the questionnaire survey. Furthermore, the dynamic changes in terms of the human population, livestock, agricultural land, water bodies and forested land for the past 25 years were investigated during the questionnaire survey. The variation of opinions obtained from respondents across the three study villages was analyzed using the Kruskal Wallis statistical test.

Land use land cover (LULC) types and changes in Kihansi area
In 1995 forested land covered the largest area 33921.83 acres (70.80%) followed by agricultural land 10520.15 acres (21.95%) and settlement 3475.14 acres (7.25%  Figure 2). There was a consistent decrease in forested land from 70.80% coverage in 1995 to 54.20% in 2004 and 40.87% in 2020. Settlements had increased by about 26.23% over the past 25 years (between 1995 and 2020), while agricultural land has increased by about 3.7% suggesting that the area that was previously forested land was converted into settlements and agricultural land ( Table 2).

Responses of respondents on the trends of LULCC in Kihansi area
The respondents reported an increase in agricultural/cultivated land in all three study villages. Forested land was reported to decrease in udagaji and Mgugwe villages while increasing in Ukami villages. Furthermore, livestock and human populations have been reported to increase in all villages. An increase in cultivated land and reduction of forested land was due to increase in the human population and livestock which were geared by birth and immigration. Other ndings have shown that, human and livestock population increase when there is high births and immigration rate. Births and immigration are in uenced by availability of pasture, fertile soils food and good socio-services (health, education, roads, railway, water, electricity) (Mmbaga, et al., 2017;Thet, 2014).
Increases in human and livestock populations in uences land cover change through deforestation, lumbering, pole cutting, grazing areas and the need for settlement areas (Karraker, et al., 2018). Different studies have shown that an increase in human population in uences land cover changes which affect biodiversity conservation through habitat destruction (Karraker, et al., 2018;Mmbaga, et al., 2017). For instance the study by Karraker, et al., (2018) in Southeast Asian forests showed that agriculture is the major land use which converts forested land to other cover types leading to habitat loss. In addition, a study conducted in Indonesia showed that human settlement and paddy elds were the land use which changed the land cover of virgin land hence leading to decreased amphibian species diversity (Yudha et al., 2019).

Implication on the conservation of KST
It is known from elsewhere that, land use land cover changes are a major challenge in biodiversity conservation. KSTs are being re-introduced in the Kihansi gorge after being extinct in the wild. However, linking LULCC in the conservation of the KST is essential to ensure their sustainable existence as more land is needed by local communities for settlement and agriculture. The need for residential areas (settlement) and agricultural land as revealed in this study has a major contribution to the LULCC of forests in the KC and adjacent areas. The same may occur to KST if measures to rescue and restore the land cover changes that have occurred from 1995-2020 are not effectively taken.

Conclusions And Recommendation
LULC of KC and adjacent areas were observed to change over years that anticipate threatening the reintroduced KST and their habitat. Agricultural land and settlement increased with time in KC area. The increased agricultural land and settlement lead to decline of forested land in the KC ecosystem. The increase in agricultural land and settlement was promoted by the increase in human population and livestock in villages adjacent the protected areas. This study provides baseline information for land use planning in KC and adjacent areas that consider sustainable conservation of re-introduced KST while improving the livelihood of local communities adjacent to KC.

Declarations
Ethics approval and consent to participate The ethical clearance was provided by the University of Dodoma for undertaking this study with reference number MA.84/261/02. The participants for the interview were recruited after receiving their informed consent by lling the consent form.

Consent for publication
Not applicable Availability of data and materials The data and Materials are available at the University of Dodoma, Department of Biology.

Competing interests
No competing interests exist

Funding
The funding for this study as accrued from family members as effort to accomplish MSc studies.

Authors' contributions
Atuhombye Sigala structured and designed the manuscript, Kelvin Ngongolo analyzed the data through statistical,edited manuscript and formatted according to the guideline while Naza Mmbaga Analysed and synthesized the information on Land Use land cover changes  Figure 1 Map showing the study area, in Kihansi catchment and adjacent areas of southern-central Tanzania