Trait and Demography of Khaya Grandifoliola Populations in Forests

Abstract

In the context of climate change, the conservation and management of tropical forests are the main priorities worldwide. Or climate change and anthropogenic pressures lead to changes in biodiversity and to the resilience of certain species in the face of extreme climatic and anthropogenic events. However, quantifying the resilience of species and their ecosystems is an important challenge for biodiversity conservationists and managers. The resilience of a species being the capacity of plants to persist or maintain their function in the face of disturbances, understanding the processes that determine the structure and dynamics of the population, the community and the entire forest is a challenge under the tropics. Meeting this great challenge requires a thorough knowledge of the functioning of individuals and species.

Measurement of functional diversity are often used to represent phenotypic differences across the spatial, temporal, taxonomic and size scales of tropical forests. This link between functional traits and plant demography is fundamental for many areas of plant ecology, including climate change, ecosystem services, conservation and genomic ecology of plants.

Save your time!
We can take care of your essay

• Proper editing and formatting
• Free revision, title page, and bibliography
• Flexible prices and money-back guarantee

Place an order

Background

Forests and trees importance to the health and prosperity of the planet is universally recognized. This prompted the integration of species and ecosystems conservation as a priority of the Sustainable Development Goals (SDGs) in its point 15 (FAO 2018). Tropical gallery forests ecosystems are one teeming with many resources over-exploited by the local community. Although they also play an important role in the species migration, landscape stability and genetic exchange between geographically isolated populations, several threats disrupt these ecological functions. The disruption of ecological functions affects the supply of ecosystem services, the physiology of species which can in turn be influenced by demography, phenotypic and genetic traits. In this sense it is widely recognized that natural and anthropogenic disturbances contribute to forest species extinction.

Nowadays, functional traits evaluation is often used to understand demographic factors and their implications for tropical trees diversity and dynamics (Poorter et al. 2008, Paine et al. 2011, Iida et al. 2014, Liu et al. 2016). Understanding the mechanism between functional traits and demography is essential to highlight the ecological variability of trees, ecosystem services,communities’ dynamics, populations, genotypic and phenotypic of trees (Garnier et al. 2018). Despite the great advances made in each of the zones to understand the tropical trees dynamics, the understanding of the link between plant function, demography and dynamics is limited.

In addition, compared to taxa prevalent in ecosystems, many rare and endangered speciesmay become genetically depressed and unsustainable due to the small size of their population (Bauert et al. 1998) and the habitats fragmentation. Habitat fragmentation exacerbates these problems and represents one of the greatest threats to the survival of many species in small and / or isolated populations (Yao et al. 2007). Forests disturbance contributes to species diversity erosion as well as the species life traits and the functions resulting (Marie Caroline et al. 2018). Studying the genetic and demographic variability of the rare plant population not only improves our understanding of population dynamics, adaptation and evolution, but also provides useful information for biological conservation (Schaal et al. 1991, Luan et al. 2006).

In the tropical zone several species are subject to variable use including pruning, debarking to meet the medicinal and economic requirements of the local population (Ouédraogo-Koné et al. 2006). These forms of exploitation affect the Eco-physiological process, the demography and the species performance (Gaoue et al. 2011, OG et al. 2013). Khaya grandifoliola, one of commonly species found along galleries forest, is in danger of extinction due to anthropogenic pressures on its habitat and the forms of use it undergoes. For this fact, understanding the genetic, demographic and populations functional traits is extremely important in the evolutionary species adaptation. The evaluation of how anthropogenic pressures and ecological conditions can drive the demography, morphological and genetic traits of tropical threatened species remain a crucial research question in population ecology.

Research Objectives

The main objective of the study is to evaluate the impact of anthropogenic pressures on habitat and forms of use on the functional traits and demography of Khaya grandifoliola populations in connection with climate change in Benin.

Specifically, it is to:

• OS1: Evaluate the impact of Khaya grandifoliola adaptation strategies in face of anthropogenic pressures follow the rainfall gradient;
• OS2: Assess the impact of anthropogenic pressures on the genetic variability of Khaya grandifoliola resilience along an ecological gradient;
• OS3: Evaluate the impact of anthropogenic pressures and climatic variability on the demography of Khaya grandifoliola;
• OS4: Model the distribution of Khaya grandifoliola in the context of climate change;

Scientific Hypotheses

• H1: Khaya grandifoliola adaptation strategies vary in relation to anthropogenic pressures follow the rainfall gradient.
• H2: There are morphological and genetic variabilities in Khaya grandifoliola from a climatic zone to another in Benin.
• H3: Quantity of Khaya grandifoliola ‘s survival and growth are corelated with anthropogenic pressures and global change.
• H4: Ecological parameters (soil, climate) of Khaya grandifoliola stands vary according to climatic zones.

Material and method

This study will be conducted in West Africa with a focus on two ecological regions of Benin (6- 12 ° 50 N and 1-3 ° 40 E). The Sudanian zone (9 ° 30’-12 N) and the Sudan-Guinean zone (7 ° 30’ -9 ° 30 ’N). The Sudanian region is dominated by woodland and savannahs on ferruginous soils. Its rainfall is unimodal with an average of 1000 mm and a variant temperature between 24 and 31°C. The Sudano-Guinean region is a transition zone with such a unimodal rainfall regime and whose annual averages vary between 1100 and 1300 mm. The temperature in this region ranges from 25°C to 29°C (Adomou 2005).

Species studied

Khaya grandifoliola is a species of the family Meliaceae which extends from Guinea to Sudan and Uganda. It is on the IUCN Red List as a vulnerable species due to the loss and degradation of its habitat, as well as its selective culling. Like other Khaya spp., Stands have been depleted in many areas following centuries of commercial and traditional use. K. grandifoliola occurs in semi-deciduous forest, especially of the dry type, and in the savannah, but in this case generally along streams. It is present in lowland forests, especially gallery forests. It prefers moist but well-drained soils and is common in places on the alluvial soils of the valleys. It is used as timber and traditionally as fuelwood and for the production of charcoal. It is widely used in traditional medicine throughout its range and is pruned by livestock farmers in the dry season for livestock. It is a species that multiplies by seed, but these seeds are often already prey to insects when they are still on the tree; a selection of intact seeds must therefore be made before sowing. This slows the natural spread of the species.

Methodology

SO1: One plot of 1 ha will be established in each population. Each plot will be installed in the direction of the river and according to the width of the gallery forest to remain in the physiognomic uniformity of the gallery forest. The diameter of K. grandifoliola will be measured for all individuals of Dbh ≥ 2 cm. the adaptation of K. grandifoliola populations will be tested using anthropogenic factors in forests (demography, proximity of fields, logging, transhumance, proximity to roads) according to two ecological regions.

SO2: In each plot of 1ha, the morphological differences (leaf, fruit, seed and leaf area density of wood) will be collected. genetics analysis will be do at laboratory of K. grandifoliola will be evaluated according to the degrees of anthropization (low, medium, strong) of the forests in the two ecological zones.

0S3: In each population, we will be established 10 quadrats of 100 m² each within 1 ha. In each quadrat, we monitored all K.grandifoliola individuals with dbh ≤ 2 cm for their density, survival and growth and for new individual recruitment. The presence or not of fire within the quadrats will be noted at each census. the survival and growth of K. grandifoliola populations will be tested according to the degrees of pressure along the ecological gradient.

0S4: The geographical coordinates of K. grandifoliola will be automatically recorded. Also, existing data from the West Africa will be extracted from the global Biodiversity Information Facility online (http://www.gbif.org). Current and future climate data will be uploaded from the WorldClim database (http://www.worldclim.org) to predict favourable conditions for K. grandifoliola. The maximum entropy approach (Maxent) one of the most powerful modelling approaches will be used to model suitable habitat for this species (Phillips and Anderson 2006).

Expected results

1. Khaya grandifoliola's adaptation strategies will be evaluate under anthropogenic pressures follow the rainfall gradient;
2. Morphological variation will be studied by the means of morphometric and Genetic variability of Khaya grandifoliola along an ecological gradient will be assesses under anthropogenic pressures;
3. Demography of Khaya grandifoliola will be described and analyzed according to nthropogenic pressures across the climatic gradient.
4. Ecological data will be assessed through distribution and mapping of the species in the country, habitats characterization (climatic and edaphic conditions) and relative abundance determination.

References

1. ADOMOU, A. C. 2005. Vegetation patterns and environmental gradedients in Benin Implications for biogeography and conservation. Wageningen University.
2. BAUERT, M. R., M. KALIN, M. BALTISBERGER, and P. J. EDWARDS. 1998. No genetic variation detected within isolated relic populations of Saxifraga cernua in the Alps using RAPD markers. Mol. Ecol. 7: 1519–1527. FAO. 2018. La situation des forets du monde.
3. GAOUE, O. G., C. C. HORVITZ, and T. TICKTIN. 2011. Non-timber forest product harvest in variable environments : modeling the effect of harvesting as a stochastic sequence. Ecol. Appl. 21: 1604–1616.
4. GARNIER, E., A. FAYOLLE, M. NAVAS, C. DAMGAARD, P. CRUZ, D. HUBERT, J. RICHARTE, P. AUTRAN, C. LEURENT, and C. VIOLLE. 2018. Plant demographic and functional responses to management intensification: a long-term study in a Mediterranean rangeland. J. Ecol. 106: 1363–1376.
5. IIDA, Y., T. KOHYAMA, N. SWENSON, S. SU, C. CHEN, J. CHIANG, and I. SUN. 2014. Linking functional traits and demographic rates in a subtropical tree community: the importance of size dependency.
6. J. Ecol. 102: 641–650. LIU, X., N. SWENSON, D. LIN, X. MI, M. UMAÑA, B. SCHMID, and K. MA. 2016. Linking individual-level functional traits to tree growth in a subtropical forest. Ecology 97: 2396–2405.
7. LUAN, S. S., T. Y. CHIANG, and X. GONG. 2006. High genetic diversity vs. low genetic differentiation in Nouelia insignis (Asteraceae), a narrowly distributed and endemic species in China, revealed by ISSR fingerprinting. 2006, 98,. Ann. dBot 98: 583–589.
8. MARIE CAROLINE, M., S. NJOUONKOU, A. LEDOUX, T. LUCIE FELICITE, Z. ROMUALD DJOUDA, J. B. W. TAFFO, and N. MAMA. 2018. Land-Use/Land-Cover Change and Anthropogenic Causes Around Koupa Matapit Gallery Forest, West-Cameroon. J. Geogr. Geol. 10: 56.
9. OG, G., H. C, T. T, S. U, and S. TULJAPURKAR. 2013. Defoliation and bark harvesting affect life history traits of a tropical tree. J. Ecol. 101: 1563–1571.
10. PAINE, C., C. BARALOTO, J. CHAVE, and B. HÉRAULT. 2011. Functional traits of individual trees reveal ecological constraints on community assembly in tropical rain forests. Oikos 120: 720–727.
11. POORTER, L., S. J. WRIGHT, H. PAZ, D. D. ACKERLY, R. CONDIT, G. IBARRA-MANRÍQUEZ, K. E. HARMS, J. C. LICONA, M. MARTÍNEZ- RAMOS, S. J. MAZER, H. C. MULLER-LANDAU, M. PEÑA-CLAROS, C. O. WEBB, and V. WRIGHT. 2008. 2008. Are functional traits good predictors of demographic rates? Evidence from five Neotropical forests. Ecology 89: 1908–1920.
12. SCHAAL, B. A., W. J. LEVERICH, and S. H. ROGSTAD. 1991. Comparison of Methods for Assessing Genetic Variation in Plant Conservation Biology. In Genetics and Conservation of Rare Plants; Falk,
13. D.A., Holsinger, K.E., Eds.; ,. Oxford Univ. Press New York, NY, USA 123–134. YAO, X. H., Q. G. YE, M. KANG, and H. W. HUANG. 2007. Microsatellite analysis reveals interpopulation differention and gene flow in endangered tree Changiostyrax dolichocarpa (Styracaceae) with fragmented distribution in central China. New Phytol. 176: 472–480.