Avian Ecology in Latin American Cityscapes by Ian MacGregor-Fors & Juan F. Escobar-Ibáñez

Author:Ian MacGregor-Fors & Juan F. Escobar-Ibáñez
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

5.3.2.2 Greenspace Size and Heterogeneity

As occurs worldwide, studies focused on the relationship between urban birds and greenspace size are common in Latin America (see Chace and Walsh 2006; Evans et al. 2009; MacGregor-Fors et al. 2009; Marzluff 2016 and references therein). In general, results of these studies reinforce the existence of positive species–area relationships, suggesting that larger areas have conditions that can support more avian species, as described in the island biogeography theory (MacArthur and Wilson 1967; Urquiza and Mella 2002; Garitano-Zavala and Gismondi 2003; Faggi and Perepelizin 2006; Carbó-Ramírez and Zuria 2011). Yet, large greenspaces with higher bird diversity are often related with heterogeneous environmental conditions, involving plant diversity and physiognomic complexity, low human disturbance rates, and management regimes, among others (MacGregor-Fors et al. 2016). However, some studies performed in Latin America have not found positive species–area relationships in urban greenspaces. For example, Malagamba-Rubio et al. (2013) did not find statistical differences in bird species richness between small (0.27–3.85 ha), medium (8.63–12 ha), and large (22.04 ha) greenspaces of Querétaro, a semi-arid Mexican city. This suggests that greenspace size per se does not necessarily determine the number of bird species that can dwell within a given urban greenspace. Due to the unfavorable conditions that highly urbanized sites often pose to many bird species, small parks, squares, private gardens , median strips, and even isolated street trees may play crucial roles for birds able to use their resources and survive their hazards (Pineda-López et al. 2010; Carbó-Ramírez and Zuria 2011); however, these spaces do not necessarily ensure the maintenance of viable populations (González-Oreja et al. 2007).

Regarding greenspace heterogeneity, several studies have shown that, regardless of bird species richness, species composition can differ in contrasting conditions of vegetation heterogeneity (Manhães and Loures-Ribeiro 2005; Gómez 2006; Lopes and Anjos 2006; Caula et al. 2010). The latter does not only apply for single greenspaces, but also for urban greenspace networks, where the contribution to the total diversity increases when the array of greenspaces is diverse in terms of size, heterogeneity , vegetation traits, management, and human disturbances (Faggi and Perepelizin 2006; Cursach and Rau 2008; MacGregor-Fors et al. 2016). Caula et al. (2010), in Valencia City (Venezuela), compared two close areas of the same size embedded within the same urban matrix, but differing in complexity: the first area was highly heterogeneous, while the second one was simplified by human management. Results of this study show that bird richness was two times higher in the first area, sheltering species considered as urban ‘avoiders’ (e.g., Red Rumped Woodpecker––Veniliornis kirkii, Lineated Woodpecker––Dryocopus lineatus, Boat-billed Heron––Cochlearius cochlearius, Green Kingfisher––Chloroceryle americana). This study highlights the importance of native remnant areas that preserved vegetation heterogeneity for urban bird conservation. Similar findings have been reported comparing municipal greenspaces maintained for recreational purposes with unmaintained greenspaces in the city of Valdivia, in Southern Chile (Silva et al. 2015).

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