Impact of land use and land cover change on plant species diversity in the Mount Bambouto Caldera of the Western Highlands of Cameroon
The impact of land use and land cover (LULC) change on the diversity of plant species, loss of plant resources, and environmental degradation remains a puzzle in the context of continuous development. The quest for solutions to curb negative repercussions has increased, particularly on fragile environments where the intensity of other factors may be more aggravating. This work in the Mount Bambouto Caldera aimed to evaluate the impact of land use systems on phytodiversity and propose mitigative strategies against such impacts caused by LULC changes. Characterized by five land use systems that have evolved due to strong human pressures on agro-ecosystems over past decades, this task was achieved through surveys and stratified sampling to establish plant species diversity. The modified Whittaker technique was used comparatively in pilot studies in different strata to investigate plant species diversity. Identification and recording of plant species was followed by data analyses using Microsoft excel 2013 and SPSS version 13.0. Shannon-Wiener diversity, Pielou’s evenness, and Simpson diversity indices were used to evaluate data generated from the study plots. 415 plant species were identified with 162, 37, and 70 unique to the lowland, sub-montane and montane savannah zones respectively. Plant species diversity established according to land use management systems (LUMS) decreased with altitude and varied across LUMS with a remarkable drop in richness as the natural forest was subjected to LULC changes. This study has established, for the first time, a phytodiversity inventory of the Mount Bambouto Caldera as affected by LULC and provides the basis for management options to curb devastations and enhance conservation efforts.
Ecosystems are under increasing pressure from human activities, with land use and land use change at the forefront of the drivers that provoke global and regional plant diversity loss (Souza et al., 2015).
The Millennium Ecosystem Assessment (MEA, 2005), intimates that habitat change brought about by land use and land use change (LULUC) is one of the drivers of terrestrial phytodiversity loss, together with climate change, invasive alien species, over exploitation of resources, and pollution.
A major effect of land use on land cover is deforestation, which is rampant in the tropics, accounting for about 8% of anthropogenic carbon dioxide (CO2) emissions and is the primary cause of species extinctions (Gullison et al., 2007; Raupach et al., 2007; Tubiello et al., 2015).
The decline in plant species diversity occurring rapidly worldwide due to land use and land cover changes adversely affects the functioning, services and stability of ecosystems (MEA, 2005; Naeem et al., 2009)and is becoming a threat to the livelihood of the inhabitants of the Mount Bambouto Caldera (Ayonghe and Ntasin, 2008).
Plant diversity in terms of richness and evenness of species, alleles, functional groups, or ecosystems (Isbell, 2012) is one of the most negatively impacted in all land use and land cover changes.
This results in imbalances in environmental moderation, the quality of natural resources and natural resource provision (food, medicine, and building materials), which all play back on human life either in the meantime or in the future.
Positive relationships between plant diversity and ecosystem functions such as carbon sequestration have been identified in some model ecosystems (van Ruijven and Berendse, 2005), although such relationships appear complex and the positive species/functional diversity relationships are not always very evident (Cadotte et al., 2011).
However, limited understanding of the interrelated effects of land use and land cover change on plant diversity hinders the ability to establish and/or project how accelerated conversions of natural forest will impact the area’s terrestrial ecosystem services.
The building up of negative consequences of land use and land cover change on humans and the environment propels the need to inventory and conserve biodiversity, and build and strengthen capacities of smallholder farmers who are already caught in the vicious cycle of poverty, food insecurity and natural resources degradation alleged in the Mount Bambouto Caldera (Ayonghe and Ntasin, 2008).
The Mount Bambouto Caldera which falls within the Cameroon volcanic line, habours rich mineral soils that favour plant growth and various agricultural practices, thereby attracting increasing human settlement in the area (Zangmo et al., 2011).
With steady increase in human activities and high levels of unprecedented deforestation around this mountain area (Fonge, 2012), phytodiversity and conservation efforts have become issues and the future of the phytobiota of this area uncertain (Ndam et al., 2015).
Studies in the area have opined a great loss in the resource base triggered by anthropogenic activity in the past decades, and the fragility of its predominantly steep slopes, which are marked by frequent mass movements in the rainy season (Ayonghe and Ntasin, 2008). Harvey et al. (2010) reported that 70% of the Mount Bambouto Caldera is unknown to botanical science and needs to be inventoried and conserved to avoid the present state of wanton species loss from land uses and frequent natural hazards. Hence, this work aimed to investigate the impacts of land use on plant diversity and establisha baseline plant checklist for future studies in plant resources conservation efforts in the Mount Bambouto Caldera.
Source : Impact of land use and land cover change on plant species diversity in the Mount Bambouto Caldera of the Western Highlands of Cameroon
