**Table 5.**

*Mean, standard deviation and ANOVA of biodiversity indicators soil on each soil degradation classes.*

*Soil Erosion - Current Challenges and Future Perspectives in a Changing World*

**3.2 Impacts of soil degradation on vegetation structure**

**4.1 Impacts of soil degradation on phytodiversity**

**Tables 6** and **7** summarize the results of MRPP computed on cover data of each plots. First, all the degradation soil classes were considered together (**Table 6**). Thereafter, the degradation soil classes were considered two by two (**Table 7**). Considering all soil degradation classes, the results showed that the vegetation cover data for the four soil degradation classes were significantly different (**Tables 5** and **6**). However, the pairwise comparison (**Table 7**) gave more details and showed that the vegetation cover data of moderately and highly degraded soils were broadly overlapping (p > 0.05). Moderate and high degraded soils presented a relative similar vegeta-

*Projection of soil degradation classes in the canonical system axis based on biodiversity indicators.*

The similarity index of Jaccard was significantly different on all the soil degradation classes and revealed that all soil degradation classes were dissimilar, depending on the floristic composition. The results allowed us to conclude that soil degradation induced modification of the floristic composition of vegetation. This finding

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tion type i.e. shrub savannas.

**4. Discussion**

**Figure 2.**

**Figure 3.**

*(a) Weighted spectrum of chorological types, (b) life forms and (c) dispersal types on soil degradation classes. SG: Sudano-Guinean, SZ: Sudano-Zambezian, S: Sudanian/Th: Therophytes, G: Geophytes, Hc: Hemicryptophytes, Ch: Chamephytes, Ph: Phanerophytes, L: Lianas / Ballo: Ballochory, Sarco: Sarcochory, Desmo: Desmochory, pogo: Pogonochory, Ptero: Pterochory, Sclero: Sclerochory.*

could be explained by the fact that the soil aggregate stability is closely related to soil organic matter composition [35], biological activity [36], infiltration capacity [37], water absorption and retention in the biomass and upper rhizosphere [38, 39] and erosion resistance [37]. Physical soil degradation on the hillsides of Atacora

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dation classes.

*Significant at 0.1. \*\*Significant at 0.05. \*\*\*Significant at 0.001.*

biodiversity and disturbance of vegetation.

*The Impacts of Soil Degradation Effects on Phytodiversity and Vegetation Structure on Atacora…*

Light 10 0.12 0.42486681 −6.7528582\*\*\* 0.00000064

*A: Chance-corrected within-group agreement P: Probability of a smaller or equal delta T: Test statistic.*

**Soil classes compared A T P** High vs. Moderate 0.17460317 −1.68534137\* 0.05423789 High vs. Light 0.21250178 −3.18865435\*\* 0.00515585 High vs. Extreme 0.37185184 −3.98260352\*\* 0.00360514 Moderate vs. Light 0.14571143 −2.20526374\*\* 0.02559057 Moderate vs. Extreme 0.30172839 −3.95512754\*\* 0.00298946 Light vs. Extreme 0.30594002 −6.68470594\*\*\* 0.00005983

**A T P**

**distance**

mountain was characterized by the removal of the organic layer and the modification of soil structure leading to the occurrence of ferricrete (extremely degraded soils) [17]. Soil degradation had resulted in soil loss, nutrient depletion, changes in soil structure, and soil hardening that limited plant root system penetration. Thus, only the most adapted species to the soil conditions were found on each soil degra-

*Chance-corrected within-group agreement P: Probability of a smaller or equal delta T: Test statistic.*

Moreover, the changes in species lists have been accompanied by a decrease of species richness and the number of regional species, phanerophytes and sarcochory as opposed to the number of species with wide distribution, therophytes and sclerochory. Many studies about post crop plant succession in Africa, United States and Europe [18, 21, 40, 41], or forest regeneration [7, 42] had shown that therophytes and sclerochory were pioneer species, which well-developed on disturbed areas, while phanerophytes and sarcochory colonized less disturbed areas. Moreover, according to references [23, 43, 44], therophytes and sclerochory developed a "ruderal" life strategy (habitat with high disturbance) and were submitted to a reproductive strategy of type r (rapid growth, effective dispersal and great invest in reproduction) while phanerophytes and sarcochory developed "competitive" or "stress-tolerant" strategies (habitat with low disturbance) and were submitted to a reproductive strategy type K (slow growth, effective use of resources and low invest in reproduction). The results then suggest that soil degradation leads to a loss of

As far as chorological types are concerned, we have reached the same conclusion of disturbance gradient. Indeed, regional species considered as indigenous or native species are found in great number in undisturbed areas and their number decrease

*DOI: http://dx.doi.org/10.5772/intechopen.93899*

**Soil classes Size Average** 

Moderate 3 0.14 High 3 0.29 Extreme 6 0.15

*Global comparison with multi response permutation procedures.*

*Pairwise comparisons with multi response permutation procedures.*

*\*\*\*Significant at 0.001.*

**Table 6.**

*\**

**Table 7.**

*The Impacts of Soil Degradation Effects on Phytodiversity and Vegetation Structure on Atacora… DOI: http://dx.doi.org/10.5772/intechopen.93899*


*A: Chance-corrected within-group agreement P: Probability of a smaller or equal delta T: Test statistic. \*\*\*Significant at 0.001.*

#### **Table 6.**

*Soil Erosion - Current Challenges and Future Perspectives in a Changing World*

could be explained by the fact that the soil aggregate stability is closely related to soil organic matter composition [35], biological activity [36], infiltration capacity [37], water absorption and retention in the biomass and upper rhizosphere [38, 39] and erosion resistance [37]. Physical soil degradation on the hillsides of Atacora

*(a) Weighted spectrum of chorological types, (b) life forms and (c) dispersal types on soil degradation classes. SG: Sudano-Guinean, SZ: Sudano-Zambezian, S: Sudanian/Th: Therophytes, G: Geophytes, Hc: Hemicryptophytes, Ch: Chamephytes, Ph: Phanerophytes, L: Lianas / Ballo: Ballochory, Sarco: Sarcochory,* 

*Desmo: Desmochory, pogo: Pogonochory, Ptero: Pterochory, Sclero: Sclerochory.*

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**Figure 3.**

*Global comparison with multi response permutation procedures.*


*Chance-corrected within-group agreement P: Probability of a smaller or equal delta T: Test statistic. \* Significant at 0.1.*

*\*\*Significant at 0.05.*

*\*\*\*Significant at 0.001.*

#### **Table 7.**

*Pairwise comparisons with multi response permutation procedures.*

mountain was characterized by the removal of the organic layer and the modification of soil structure leading to the occurrence of ferricrete (extremely degraded soils) [17]. Soil degradation had resulted in soil loss, nutrient depletion, changes in soil structure, and soil hardening that limited plant root system penetration. Thus, only the most adapted species to the soil conditions were found on each soil degradation classes.

Moreover, the changes in species lists have been accompanied by a decrease of species richness and the number of regional species, phanerophytes and sarcochory as opposed to the number of species with wide distribution, therophytes and sclerochory. Many studies about post crop plant succession in Africa, United States and Europe [18, 21, 40, 41], or forest regeneration [7, 42] had shown that therophytes and sclerochory were pioneer species, which well-developed on disturbed areas, while phanerophytes and sarcochory colonized less disturbed areas. Moreover, according to references [23, 43, 44], therophytes and sclerochory developed a "ruderal" life strategy (habitat with high disturbance) and were submitted to a reproductive strategy of type r (rapid growth, effective dispersal and great invest in reproduction) while phanerophytes and sarcochory developed "competitive" or "stress-tolerant" strategies (habitat with low disturbance) and were submitted to a reproductive strategy type K (slow growth, effective use of resources and low invest in reproduction). The results then suggest that soil degradation leads to a loss of biodiversity and disturbance of vegetation.

As far as chorological types are concerned, we have reached the same conclusion of disturbance gradient. Indeed, regional species considered as indigenous or native species are found in great number in undisturbed areas and their number decrease

along the gradient while species with wide distribution or immigrant species increase in number and are numerous on very disturbed areas [21, 45]. Thus, the vegetation trend over the different soil degradation classes followed a retrograde succession from the least disturbed soils (slightly degraded soils) to the most disturbed soils (extremely degraded soils) through intermediate stages (moderately and highly degraded soils).
