At the beginning of any distributional study, things seem simple, and one begins only by counting species and individuals, or any biodiversity level. However, when we include size scales of time, space, and the factors that determine the distributions of those species, the overview becomes more complex. To illustrate these changes, we considered taking one of the most charismatic groups of birds that inhabit the planet: the "parakeets, macaws & parrots" of the Psittacidae family.
Mexico harbors 22 species of Psittacines whose populations struggle to survive due to pet trafficking, and the destruction/fragmentation of tropical and temperate forests where they live \citep{Plasencia_V_zquez_2017} \citep{rubio-rocha2016}. In the Yucatan Peninsula before the 1980s, only eight species had been recorded: Scarlet Macaw (Ara macao), Olive-throated Parakeet (Eupsittula nana), Brown-hooded Parrot (Pyrilia haematotis), White-crowned Parrot (Pionus senilis), White-fronted Parrot (Amazona albifrons), Yellow-lored Parrot (A. xantholora), Red-lored Parrot (A. autumnalis),  and Mealy Parrot (A. farinosa). In 2001, the Red Macaw was considered extinct  due to the pet trade \citep{contreras2010} \cite{vargas-soriano2001}. However, a few years later during 2002-2003 explorations in the most extreme and wettest region of Campeche, the Yellow-headed Parrot (A. oratrix) was added to the species list \citep{elas2003} and during 2014, birdwatchers reported the Monk Parakeet (Myiopsitta monachus) in Ciudad del Carmen, Campeche. Thus, two species were added but we lost the largest species.
Does species richness has increased? In reality, the number of species shows that more places and people are interested in recording bird species. Also, there is no significant difference in species richness locally. Instead, its composition differs (i.e., the kind of species and their abundance changes). On the other hand, should we be happy to have new species even if it is exotic? There are habitat generalists such as the White-fronted Parrot, whose populations are exponentially growing in the Yucatan Peninsula. While the Mealy Parrot, whose populations survive in the largest tropical forest fragments, is becoming rarer (Plasencia-Vázquez et al. 2017) \citep{escalona-segura2014}. Therefore, although numbers are significant, it is equally important to know what those numbers represent.    
If you have a Monk Parakeet , keep it at home!
 

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