**4. Discussion**

The loss of biodiversity is one of the environmental problems that has managed to arouse broad global interest in the last two decades [4, 23]. Some of the main

causes are related to human activities, either directly (overexploitation) or indirectly (habitat alteration), although there is generally an interaction

monitoring.

of las Joyas is smaller (Ca. 3600 ha.).

*Ecology of Plant Communities in Central Mexico DOI: http://dx.doi.org/10.5772/intechopen.95629*

have shown few results.

**35**

between them. The communication systems have impacted in such a way that both the government and the private sector, as well as society in general, consider a priority to direct greater efforts towards conservation programs. The basis for an objective analysis of biodiversity and its change lies in its correct evaluation and

In the Temperate Mountain Forest, the 50 woody species identified show a high species richness in comparison with other mountain regions. The best represented genera correspond to oak trees (*Quercus spp.*) and pines (*Pinus spp*.). The studied area harbors a small portion (6.8%) of the oak species that inhabit Mexico (161 species) [24]; although, this percentage is lower than those reported in areas with a greater territorial surface and higher rainfall, such as the case of San Luis Potosi and Jalisco States, which has identified 45 and 51 oak species respectively, that represent 27.95 and 36.9% of the total oak species registered in Mexico [25], the SF-NPA represent less 5% of the territorial surface in the mentioned states. In relation to pines, the studied area has about 17% of the species identified in Mexico [26]. This proportion is similar to that reported by Márquez-Linares et al., [27] in an area of pine-oak forest, in Durango, Mexico, where they recorded 8 pine species. In relation to "Las Joyas" scientific station, in the Sierra de Manantlán Biosphere Reserve, the *Quercus* diversity (16 spp.) is similar to the one in the Sierra Fria, although the area

In the Sierra Fría, the most widely distributed and abundant species are the potosine oak (*Q. potosina*) and alligator juniper (*J. deppeana*)*.* In the case of *Q. potosina*, its distribution and abundance may be related to the dominant physiography in this area, as well as to the mean annual precipitation (650 mm). The appearance of *J. deppeana* is possibly related to the disturbances that occurred in the Sierra Fria during the period between 1920 and 1940 [28]. This species has probably been a pioneer in the recovery of the vegetation cover, although the presence of manzanita (*A. pungens*) has also been documented colonizing sites where disturbances occurred, either natural, as in the case of fires or, anthropogenic, such as forest clearance and harvesting. Pines population is restricted to the Sierra Fría and the Sierra del Laurel. In the Sierra Fria, *Pinus teocote* (locally known as pino ocote) and *Pinus leiophylla* (locally known as pino prieto) are the two most abundant pine species. Its population is abundant in humid places and altitudes higher than 2,500 masl. *P. leiophylla* isolated specimens have been found on flat lands, which suggests that in the past this species had a greater distribution. In the Sierra del Laurel only two pine species have been identified, the pino triste (*Pinus lumholtzii*) and the pino piñonero (*Pinus cembroides var. cembroides*) in isolated populations, which suggests that in the past

they were more abundant; however, the existing information is incipient.

temperate forests, similar to what the β Whitakker index showed.

The *H*'diversity indexes for each altitudinal stratum suggest that, between 2,400 and 2,600 mamsl, the plant richness of the SF-Natural Protected Area is similar to

The distribution of species such as *J. deppeana* and *Q. potosina*, the most abundant and widely distributed, are influenced by flat sites and canopy covers that vary between 30 and 50%. One explanation is that *Q. potosina* tolerates high drought rates and *J. deppeana* is a pioneer species in disturbed sites, as suggested by Minnich et al. (1994) [28]. On the other hand, the presence or absence of the species may also be dictated due to their dispersal capacity or to the presence or absence of dispersers [19]. The results obtained contribute to describe the habitat of the species, which is an essential factor in programs aiming the restoration and management of temperate climate forests [8, 29], actions that, at least in the case of Mexico,

#### **Figure 12.**

*Diversity of forest species in the tropical dry Forest. (a) Landscape of the tropical dry Forest in the Terrero de la labor and las Moras Ejido; (b) an example of* Manihot caudata*, locally known as jaboncillo; (c) specimen of* Bursera fagaroides *(locally known as venadilla or papelillo). Photographs courtesy of Vicente Díaz Núñez, Joaquín Sosa-Ramírez and Jesús Argumedo-Espinoza.*

#### *Ecology of Plant Communities in Central Mexico DOI: http://dx.doi.org/10.5772/intechopen.95629*

**4. Discussion**

**Figure 12.**

**34**

*Joaquín Sosa-Ramírez and Jesús Argumedo-Espinoza.*

The loss of biodiversity is one of the environmental problems that has managed to arouse broad global interest in the last two decades [4, 23]. Some of the main

*Natural History and Ecology of Mexico and Central America*

*Diversity of forest species in the tropical dry Forest. (a) Landscape of the tropical dry Forest in the Terrero de la labor and las Moras Ejido; (b) an example of* Manihot caudata*, locally known as jaboncillo; (c) specimen of* Bursera fagaroides *(locally known as venadilla or papelillo). Photographs courtesy of Vicente Díaz Núñez,*

causes are related to human activities, either directly (overexploitation) or indirectly (habitat alteration), although there is generally an interaction between them. The communication systems have impacted in such a way that both the government and the private sector, as well as society in general, consider a priority to direct greater efforts towards conservation programs. The basis for an objective analysis of biodiversity and its change lies in its correct evaluation and monitoring.

In the Temperate Mountain Forest, the 50 woody species identified show a high species richness in comparison with other mountain regions. The best represented genera correspond to oak trees (*Quercus spp.*) and pines (*Pinus spp*.). The studied area harbors a small portion (6.8%) of the oak species that inhabit Mexico (161 species) [24]; although, this percentage is lower than those reported in areas with a greater territorial surface and higher rainfall, such as the case of San Luis Potosi and Jalisco States, which has identified 45 and 51 oak species respectively, that represent 27.95 and 36.9% of the total oak species registered in Mexico [25], the SF-NPA represent less 5% of the territorial surface in the mentioned states. In relation to pines, the studied area has about 17% of the species identified in Mexico [26]. This proportion is similar to that reported by Márquez-Linares et al., [27] in an area of pine-oak forest, in Durango, Mexico, where they recorded 8 pine species. In relation to "Las Joyas" scientific station, in the Sierra de Manantlán Biosphere Reserve, the *Quercus* diversity (16 spp.) is similar to the one in the Sierra Fria, although the area of las Joyas is smaller (Ca. 3600 ha.).

In the Sierra Fría, the most widely distributed and abundant species are the potosine oak (*Q. potosina*) and alligator juniper (*J. deppeana*)*.* In the case of *Q. potosina*, its distribution and abundance may be related to the dominant physiography in this area, as well as to the mean annual precipitation (650 mm). The appearance of *J. deppeana* is possibly related to the disturbances that occurred in the Sierra Fria during the period between 1920 and 1940 [28]. This species has probably been a pioneer in the recovery of the vegetation cover, although the presence of manzanita (*A. pungens*) has also been documented colonizing sites where disturbances occurred, either natural, as in the case of fires or, anthropogenic, such as forest clearance and harvesting. Pines population is restricted to the Sierra Fría and the Sierra del Laurel. In the Sierra Fria, *Pinus teocote* (locally known as pino ocote) and *Pinus leiophylla* (locally known as pino prieto) are the two most abundant pine species. Its population is abundant in humid places and altitudes higher than 2,500 masl. *P. leiophylla* isolated specimens have been found on flat lands, which suggests that in the past this species had a greater distribution. In the Sierra del Laurel only two pine species have been identified, the pino triste (*Pinus lumholtzii*) and the pino piñonero (*Pinus cembroides var. cembroides*) in isolated populations, which suggests that in the past they were more abundant; however, the existing information is incipient.

The *H*'diversity indexes for each altitudinal stratum suggest that, between 2,400 and 2,600 mamsl, the plant richness of the SF-Natural Protected Area is similar to temperate forests, similar to what the β Whitakker index showed.

The distribution of species such as *J. deppeana* and *Q. potosina*, the most abundant and widely distributed, are influenced by flat sites and canopy covers that vary between 30 and 50%. One explanation is that *Q. potosina* tolerates high drought rates and *J. deppeana* is a pioneer species in disturbed sites, as suggested by Minnich et al. (1994) [28]. On the other hand, the presence or absence of the species may also be dictated due to their dispersal capacity or to the presence or absence of dispersers [19]. The results obtained contribute to describe the habitat of the species, which is an essential factor in programs aiming the restoration and management of temperate climate forests [8, 29], actions that, at least in the case of Mexico, have shown few results.

The species richness in BTS is generally lower than in humid tropical forests [30], although higher than in Temperate Mountain Forests [25]. The BTS is dominated by relatively short trees, most of which lose all their foliage during the dry season. In this community, herbaceous life form, thin woody species, and vines are common, but epiphytes and thick lianas are less abundant and diverse than in humid forests [31]. Diversity is generally higher without a clear dominance of any species, to the point that many of them are rare [32]. In this type of ecosystem, it is common to identify some genera such as *Bursera, Lonchocarpus, Lysiloma* and *Jatropha*, as well as emerging columnar cacti [33].

The species richness found at the Terrero de la labor Ejido BTS (N = 79) is similar to that reported by Trejo (2005) [33], where he points out that on average the tropical dry forest in Mexico harbors around 74 species with a DBH ≥ 1 cm in 0.1 ha. However, in the study site, some species considered "rare" which are indicators of medium forest (e.g *Amphipterygium molle*) were found in ravines and better preserved sites, suggesting that at some point this ecosystem had a greater presence in the landscape.

The analysis of the diversity, distribution and abundance associated with the Tropical Dry Forest in Aguascalientes has been little addressed, so the study conducted in the BTS of the Municipality of Calvillo represents one of the first efforts to understand this ecosystem natural heritage [14]. Previously, partial floristic studies had been carried out, studies which mainly referred to the dominant vegetation types and some important species, however on these studies there were gaps in relation to the ecology of the plant communities [20]. On the other hand, other studies mention some factors related to the mortality of these natural communities [15], but there is no information on vegetation diversity which reflects the real tropical dry forest importance.

This work contributes directly to the management of the ecosystems analyzed. Knowledge about species richness and their distribution provides an overview of the territory's conservation state, considering that both the Temperate Mountain Forest and the Tropical Dry Forest studied are part of the Sierra Fria Protected Natural Area, which is the protected area with the biggest extension in the State. On the other hand, the bases are established for the restoration of degraded ecosystems, either through active restoration or through mechanisms of ecological succession (passive restoration) [29].

**Author details**

Joaquín Sosa-Ramírez<sup>1</sup>

*Ecology of Plant Communities in Central Mexico DOI: http://dx.doi.org/10.5772/intechopen.95629*

Aguascalientes, Ags., México

Morelia, Mich, Mexico

**37**

\*, Vicente Díaz-Núñez<sup>2</sup> and Diego R. Pérez-Salicrup<sup>3</sup>

1 Agricultural Sciences Center, Autonomous University of Aguascalientes, Av.

2 Scientific Research Invited by the Agricultural Sciences Center, Autonomous University of Aguascalientes, Avenida Universidad, Ciudad Universitaria,

3 Ecosystem Research Institute, National Autonomous University of Mexico,

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Universidad, Ciudad Universitaria, Aguascalientes, Ags., México

\*Address all correspondence to: jsosar@correo.uaa.mx

provided the original work is properly cited.

#### **Acknowledgements**

The authors acknowledge the participation of Jesus Argumedo-Espinoza for his cartographic support. Likewise, we thank the facilities provided of the owners of the Sierra Fria, as well as Jesus Velasco Serna of the Terrero de la Labor ejido for in the gathering of field information.

*Ecology of Plant Communities in Central Mexico DOI: http://dx.doi.org/10.5772/intechopen.95629*

The species richness in BTS is generally lower than in humid tropical forests [30], although higher than in Temperate Mountain Forests [25]. The BTS is dominated by relatively short trees, most of which lose all their foliage during the dry season. In this community, herbaceous life form, thin woody species, and vines are common, but epiphytes and thick lianas are less abundant and diverse than in humid forests [31]. Diversity is generally higher without a clear dominance of any species, to the point that many of them are rare [32]. In this type of ecosystem, it is common to identify some genera such as *Bursera, Lonchocarpus, Lysiloma* and

The species richness found at the Terrero de la labor Ejido BTS (N = 79) is similar

The analysis of the diversity, distribution and abundance associated with the Tropical Dry Forest in Aguascalientes has been little addressed, so the study conducted in the BTS of the Municipality of Calvillo represents one of the first efforts to understand this ecosystem natural heritage [14]. Previously, partial floristic studies had been carried out, studies which mainly referred to the dominant vegetation types and some important species, however on these studies there were gaps in relation to the ecology of the plant communities [20]. On the other hand, other studies mention some factors related to the mortality of these natural communities [15], but there is no information on vegetation diversity which reflects the

This work contributes directly to the management of the ecosystems analyzed. Knowledge about species richness and their distribution provides an overview of the territory's conservation state, considering that both the Temperate Mountain Forest and the Tropical Dry Forest studied are part of the Sierra Fria Protected Natural Area, which is the protected area with the biggest extension in the State. On the other hand, the bases are established for the restoration of degraded ecosystems, either through active restoration or through mechanisms of ecological succession

The authors acknowledge the participation of Jesus Argumedo-Espinoza for his cartographic support. Likewise, we thank the facilities provided of the owners of the Sierra Fria, as well as Jesus Velasco Serna of the Terrero de la Labor ejido for in

to that reported by Trejo (2005) [33], where he points out that on average the tropical dry forest in Mexico harbors around 74 species with a DBH ≥ 1 cm in 0.1 ha. However, in the study site, some species considered "rare" which are indicators of medium forest (e.g *Amphipterygium molle*) were found in ravines and better preserved sites, suggesting that at some point this ecosystem had a greater presence in

*Jatropha*, as well as emerging columnar cacti [33].

*Natural History and Ecology of Mexico and Central America*

the landscape.

real tropical dry forest importance.

(passive restoration) [29].

**Acknowledgements**

**36**

the gathering of field information.
