Lippia alba (Mill.) Britton & P.Wilson Shrub Native Cultivated Med

García, Néstor, Peñaranda, Juanita & Sarmiento, Natalia, 2021, Diversity and use of trees and shrubs in smallholder farming systems in the Colombian Andes, Caldasia 43 (1), pp. 49-64 : 60-61

Lippia alba (Mill.) Britton & P.Wilson Shrub Native Cultivated Med 1 (0.04)

Another interesting aspect of tree and shrub diversity on the farms is the predominance of native species over exotic species, consistent with what is reported in the literature for smallholder farming systems in the Neotropics ( Albuquerque et al. 2005, Garen et al. 2011, Abebe et al. 2013, Pérez and Matiz-Guerra 2017, Rooduijn et al. 2018). However, although exotic species were less diverse than native ones, they are the most frequent on farms. In fact, of the seven most frequent species, six were exotic and only one was native. This lower diversity but high frequency of exotic species may be related to the fact that in human-modified systems exotic species tend to offer many more services ( Garen et al. 2011). In fact, 98 % of the exotic species were useful in the studied farms. In contrast, native species were less frequently utilized and were used in a smaller proportion (23 %). The most frequent native species were found in no more than half of the farms and corresponded to cultivated species, all with some usevalue for the owners.

Regardless of the origin and the diversity of tree and shrub species found in smallholder farms, our results suggest that these productive spaces may have a key role in biodiversity conservation. In this sense, several authors have reported that environments altered by humans, such as home gardens, are spaces for the conservation of wild species and are germplasm reservoirs of a wide variety of cultivated plants ( Bhagwat et al. 2008, Pulido et al. 2008, Webb and Kabir 2009, Rooduijn et al. 2018). Some of the most characteristic genera of the Andean flora, such as Baccharis , Solanum , Fuchsia , Miconia , Piper , Chromolaena , Cestrum , Oreopanax , Tibouchina , Myrsine or Monnina ( García et al. 2006, Fernández-Alonso and Hernández-Schmidt 2007, González-M and López-Camacho 2012) are represented by one or several species within the farms studied ( Table 1). Likewise, it is significant that eight of the wild species are endemic to Colombia (Bernal et al. c2019). Additionally, some of the genera of cultivated plants frequently reported in Neotropical agricultural systems such as Abutilon , Annona , Citrus , Inga, Manguifera , Prunus , Psidium , Solanum or Syzygium ( Pulido et al. 2008, Pérez and Matiz-Guerra 2017, Pinto Rayol et al. 2017, Villa and García 2018), are also represented in the farms studied with one or more species ( Table 1). These results reinforce the idea that smallholder farms can play a significant role in biodiversity conservation strategies.

What are the characteristics of the smallholder farming systems that favor this tree and shrub diversity? One of the practices that favor the existence of wild diversity in the farms is the maintenance of the original native vegetation or allowing the establishment of wild plants that arrive by natural dispersal. The motivations of owners who allow the establishment of these wild species may be related to their perception of the environment. The tendency for organic practices on these farms implies that the owners value the services that wild species can offer, such as shade in pastures, a supply of food for birds and insects or the protection of hatcheries or water sources. The establishment of wild species is influenced by the surrounding flora, but their maintenance on farms depends on the actions or practices of the owners ( Rooduijn et al. 2018).

Another aspect that favors tree diversity on farms is the presence of various spaces within the farms, such as home gardens, living fences or forest relics. This complex structure is characteristic of smallholder farming systems and has been described in various family production systems around the world ( Kehlenbeck et al. 2007, Pulido et al. 2008, Abebe et al. 2013, Mohri et al. 2013). In the studied farms, most of the tree species diversity was found in productive areas, which included home gardens and cultivated or grazing areas. The fact that these are precisely the areas of greatest human intervention indicates that the presence of trees and shrubs depends on the decisions of the owners. This confirms the statement by Thijs et al. (2015) who recognize that the occurrence of tree species in agricultural systems is highly influenced by human in- terventions. In Panama, for example, farmers perform various tree management practices, assigning value to native species ( Garen et al. 2011). Living fences also turn out to be another space that protects a variety of trees and shrubs, since these are important spaces for the establishment of wild plants along with the species planted by the owners. The role of living fences as areas for the establishment and conservation of tree species has already been documented for the Colombian Andes ( Pulido-Santacruz and Renjifo 2011). Spaces with remaining native vegetation, such as forest relics, also contribute significantly to maintaining tree diversity on these farms.