**1. Introduction**

#### **1.1 Flora, fauna and vegetation**

Mesoamerica (starting from the southern states of Mexico) differs from Central America, which is a geopolitical name. The expression "Middle America" is in use as well, which involves all areas south from the border of the US including the Islands of the Caribbean [1]. In this chapter the biodiversity of Mexico is presented and the literature on its protection is analyzed.

Mexico being the largest country in the region is very rich in species in itself (**Tables 1**–**4**). Lot of species occur even in the dry northern areas. In the Chihuahuan Desert 826 plant species are noted by Villarreal-Quintanilla et al. [7], out of which 560 are endemic, 165 are quasi-endemic and és 176 are microendemic. 116 taxa can be originated from a non-arid habitat. The most species-rich are Cactaceae with 141, Asteraceae with 106, Boraginaceae with 34 and Brassicaceae with 31 species. On the California Peninsula 723 endemic species are noted by Riemann and Exequiel [8], claiming that the great number of endemic species is due to the heterogenity of the environment. The flora and fauna are very interesting because the area of Mexico involves the border of *Neotropis* and *Nearctis* (Mexican Transition Zone), which is not exactly a border but rather a wide transition zone, its accurate definition is yet to be created. The determinaion is based on the distribution of the endemic genera characteristic to one or the other area. The several results obtained regarding this vary hugely. The determination of the location and width of the transition zone is different among authors without a consensus, which requires further floristic examinations [9]. Vegetatio varies depending on the topography that has a great role in the fromation of the great number of endemic species as well [10].


#### **Table 1.**

*Biodiversity of Mexico according to Mittermeier et al. [2].*

#### *Natural History and Ecology of Mexico and Central America*


#### **Table 2.**

*Flora of Mexico according to vegetation types based on Flores-Villela and Gerez [3].*


**5**

**Table 3.**

*Introductory Chapter: Biodiversity of Mexico DOI: http://dx.doi.org/10.5772/intechopen.98690*

Sierra Juárez and San Pedro Mártir

Trans-Mexican volcanic belt pine-oak

**Deserts and Xeric Shrublands**

**Flooded Grasslands and Savannas**

**Montane Grasslands and Shrublands**

**Mediterranean Forests, Woodlands, and Scrub**

**Mangroves**

pine-oak forests

forests

**Biom/ecoregions Area (km2**

**Tropical and Subtropical Grasslands, Savannas, and Shrublands**

Sierra Madre de Oaxaca pine-oak forests 14299 2500–3700 55 Sierra Madre del Sur pine-oak forests 60976 3600–5000 43 Sierra Madre Occidental pine-oak forests 222700 ND ND Sierra Madre Oriental pine-oak forests 65600 ND ND

Western Gulf coastal grasslands 77425 2150–2250 3

Baja California desert 45940 1500–2200 8 Central Mexican matorral 59195 2500–4500 0,011 Chihuahuan desert 501896 3300–3600 50 Gulf of California xeric shrub 22573 900–1900 29 Meseta Central matorral 124975 3000–4500 4 San Lucan xeric scrub 3685 ND 12 Sonoran desert 260000 2600–3000 37 Tamaulipan matorral 16300 1500–2500 9 Tamaulipan mezquital 141500 1700–2500 23 Tehuacan Valley matorral 9842 0

Central Mexican wetlands 259 100–600 ND

Zacatonal 306 150–500 ND

Alvarado mangroves 4534 20–400 1,12

California chaparral and woodlands 121000 1550–1750 1

Marismas Nacionales-San Blas mangroves 2034 20–400 Mayan Corridor mangroves 4079 20–400 Mexican South Pacific Coast mangroves 1168 20–400 Petenes mangroves 1971 20–400 Ría Lagartos mangroves 3457 20–400 Tehuantepec-El Manchon mangroves 2685 20–400 Usumacinta mangroves 3118 20–400

*Bioms and ecoregions of Mexico according to Kier et al. [4] and Dinerstein et al. [5].*

**) Estimated number of species**

4000 ND ND

91800 4000–6000 26

**Remaining intact vegetation %**

#### *Introductory Chapter: Biodiversity of Mexico DOI: http://dx.doi.org/10.5772/intechopen.98690*

*Natural History and Ecology of Mexico and Central America*

**Biom/ecoregions Area (km2**

*Flora of Mexico according to vegetation types based on Flores-Villela and Gerez [3].*

Chiapas moist forests 5759 3000–4500 67 Chimalpas montane forests 2076 2000–3000 49 Pantanos de Centla 17152 1500–3000 11 Petén-Veracruz moist forests 148604 5000–8000 31 Sierra de los Tuxtlas 3890 2400–3500 11 Sierra Madre de Chiapas moist forests 11218 3500–4700 34 Veracruz moist forests 68949 4500–7000 20 Veracruz montane forests 4942 2200–3500 55 Yucatán moist forests 69485 1300–1900 64

**Vegetation % area Number of species Endemisms %** Cloud forest 0.7 3000 30 Rainforest 4.4 5000 5 Pine and oak 12.9 7000 70 Xerophyl and steppe 34.8 6000 60 Wetlands 1.43 1000 15 Tropical deciduous 7.9 6000 40 Agricultural and ruderal ND 2000 20

Bajío dry forests 37282 2900–5000 0,64 Balsas dry forests 62249 2500–5100 2 Central American dry forests 67777 2800–400 12 Chiapas Depression dry forests 13974 1500–3500 7 Jalisco dry forests 26051 1000–2500 26 Revillagigedo Islands dry forests 210 ND ND Sierra de la Laguna dry forests 3975 500–1000 0,008 Sinaloan dry forests 77364 1700–2500 13

Southern Pacific dry forests 42283 2500–5100 15 Veracruz dry forests 6616 900–2000 5

Central American pine-oak forests 110948 4000–6000 42 Sierra de la Laguna pine-oak forests 1061 700–1200 4

**Tropical and Subtropical Moist Broadleaf Forests**

**Tropical and Subtropical Dry Broadleaf Forests**

Sonoran-Sinaloan transition subtropical

**Tropical and Subtropical Coniferous Forests**

dry forest

**Table 2.**

**) Estimated number of species**

50326 ND ND

**Remaining intact vegetation %**

**4**


#### **Table 3.**

*Bioms and ecoregions of Mexico according to Kier et al. [4] and Dinerstein et al. [5].*

#### *Natural History and Ecology of Mexico and Central America*


**Table 4.**

*Bird and mammalian fauna of Mexico according to CONABIO [6] (National Commission for knowledge and use of biodiversity) by states. In coastal states marine mammals are included.*

The climate formed by the emerging mountains (Sierra Madre Oriental, Sierra Madre Occidental, Trans-Mexico Volcanic Belt) also affects evolutionary processes resulting in the development of new species [11, 12]. The richness of species and the species composition of the community depends on the heterogenity and diversity of the environment [10]. As Moonlight et al. [13] presents on the example of *Begonia* genus regarding the DNA sequence data of the plastis diversification is fast and new species develop in the hetrogeneous environment. According to their results there were two indipendent colonization events from Africa towards the Neotropis. Two

**7**

areas [24].

*Introductory Chapter: Biodiversity of Mexico DOI: http://dx.doi.org/10.5772/intechopen.98690*

Many species have a small area of distribution (75–100 km2

**2. Environmental protection and biodiversity conservation**

Since the nineties Mexico have been involved in the work of international environmental organizations with increasing activity and now have signed 44 international agreements. It is an active stakeholder of organizations such as the CBD (Convention on Biological Diversity) and CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), CEC (Commission for Environmental Cooperation), Trilateral Committee, The Ramsar Convention on Wetlands, EMSA (Mesoamerican Biological Corridor and the Mesoamerican Strategy of Environmental Sustainability). The NDP (National Development Plan) can be considered as a legal framework within the country providing basic regulations for the federal government by giving guidance for the work of the government with the development of clear strategies, setting regional aims and measures to be implemented, coordinating institutional and regional programs involving several

The program, in which Mexico also participates, aiming to preserve biodiversity is the Payments for Ecosystem Services (PES) that is an economic framework to plan and introduce payment schemes that provide market remuneration for ecosystem services [25]. This tool seems to be eligible for the protection of rainforests in the developing countries. 2.6 million hectares are involved in the program in

ticularly vulnerable [21]. A remarkable example of the destruction of human activity to habitat is the wall that is being built on the border of the US and Mexico, which parts that have already been set up initiated the reduction of size, quality and connections of habitat in the otherwise diverse area [22]. Migration of many amphibian, reptile and mammal species are hindered by the barrier and human activity. This becomes relevant when certain species look for new habitat due to climate change. Obstructing their movement endanger species or certain popoulations. The genetic diversity of species reduce with the extinction of populations endangering the entire species [23].

different clads were reconstructed, which diversified around the middle of miocene in South America and radiation occurred once towards Central America and Mexico. Today tropical deciduous forest is typical on the western side but it is fragmented due to human activity and only 3% is protected. Agriculutal areas are concentrated in areas where the climate is seasonal that is why the reduction is faster than in the case of rainforests [14]. 10% and 19.7% of tropical forest and shrubland, respecively are protected. On the east side 28% of the rainforests are protected (Estado [15]). Examinations of flora and fauna are still not complete, our knowledge on the wildlife of the area is deficient [16, 17]. New species are still identified in Mexico such as *Tryonia* (Caenogastropoda: Cochliopidae) species discovered by Hershler et al. [18] in the creeks of the Chihuahuan Desert (Durango State). Some of these probably have become extinct since they were failed to be found again. The cause of their extinction is the destruction and disappearance of their habitat. According to forcasts the average annual temperature will rise by 3,7–3,8°C to 2090 in Mexico, the amount of precipitation will reduce by 18,2% and AAI (Annual Aridity Index) will rise by 26% [19]. These will result in a 25% decrease in the value of ENS (effective number of species), if the forcasts prove to be accurate [20]. Characteristic plants of Mexico the cacti (Cactaceae) can also become rare by then due to land transforming activity of man, 31% of the species are already endangered. Climate change may cause other species to become endangered. Cacti are drought tolerant but because of climate change species may become endangered due to the reduction or extinction of pollinators and animals dispersing seeds. In the case of cacti often ants carry the seeds (Myrmecochory) only to limited distances.

) as well, making them par-

#### *Introductory Chapter: Biodiversity of Mexico DOI: http://dx.doi.org/10.5772/intechopen.98690*

*Natural History and Ecology of Mexico and Central America*

**State Birds Mammals** Veracruz 664 101 Chiapas 628 90 Oaxaca 687 116 Jalisco 481 107 Guerrero 476 72 Puebla 367 76 San Luis Potosí 469 93 Michoacán 460 79 Chihuahua 329 95 Edo. México 281 55 Tamaulipas 444 90 Sonora 456 100 Durango 308 81 Nayarit 407 72 Nuevo León 252 63 Hidalgo 236 59 Morelos 274 46 Sinaloa 460 69 Coahuila 275 80 Tabasco 370 47 Baja California 292 95 Quintana Roo 340 51 Distrito Federal 222 44 Yucatán 343 58 Baja California Sur 258 77 Colima 318 51 Zacatecas 154 75 Guanajuato 256 45 Campeche 281 50 Querétaro 181 36 Aguascalientes 89 33 Tlaxcala 89 21

The climate formed by the emerging mountains (Sierra Madre Oriental, Sierra Madre Occidental, Trans-Mexico Volcanic Belt) also affects evolutionary processes resulting in the development of new species [11, 12]. The richness of species and the species composition of the community depends on the heterogenity and diversity of the environment [10]. As Moonlight et al. [13] presents on the example of *Begonia* genus regarding the DNA sequence data of the plastis diversification is fast and new species develop in the hetrogeneous environment. According to their results there were two indipendent colonization events from Africa towards the Neotropis. Two

*use of biodiversity) by states. In coastal states marine mammals are included.*

*Bird and mammalian fauna of Mexico according to CONABIO [6] (National Commission for knowledge and* 

**6**

**Table 4.**

different clads were reconstructed, which diversified around the middle of miocene in South America and radiation occurred once towards Central America and Mexico.

Today tropical deciduous forest is typical on the western side but it is fragmented due to human activity and only 3% is protected. Agriculutal areas are concentrated in areas where the climate is seasonal that is why the reduction is faster than in the case of rainforests [14]. 10% and 19.7% of tropical forest and shrubland, respecively are protected. On the east side 28% of the rainforests are protected (Estado [15]). Examinations of flora and fauna are still not complete, our knowledge on the wildlife of the area is deficient [16, 17]. New species are still identified in Mexico such as *Tryonia* (Caenogastropoda: Cochliopidae) species discovered by Hershler et al. [18] in the creeks of the Chihuahuan Desert (Durango State). Some of these probably have become extinct since they were failed to be found again. The cause of their extinction is the destruction and disappearance of their habitat. According to forcasts the average annual temperature will rise by 3,7–3,8°C to 2090 in Mexico, the amount of precipitation will reduce by 18,2% and AAI (Annual Aridity Index) will rise by 26% [19]. These will result in a 25% decrease in the value of ENS (effective number of species), if the forcasts prove to be accurate [20]. Characteristic plants of Mexico the cacti (Cactaceae) can also become rare by then due to land transforming activity of man, 31% of the species are already endangered. Climate change may cause other species to become endangered. Cacti are drought tolerant but because of climate change species may become endangered due to the reduction or extinction of pollinators and animals dispersing seeds. In the case of cacti often ants carry the seeds (Myrmecochory) only to limited distances. Many species have a small area of distribution (75–100 km2 ) as well, making them particularly vulnerable [21]. A remarkable example of the destruction of human activity to habitat is the wall that is being built on the border of the US and Mexico, which parts that have already been set up initiated the reduction of size, quality and connections of habitat in the otherwise diverse area [22]. Migration of many amphibian, reptile and mammal species are hindered by the barrier and human activity. This becomes relevant when certain species look for new habitat due to climate change. Obstructing their movement endanger species or certain popoulations. The genetic diversity of species reduce with the extinction of populations endangering the entire species [23].
