Farmers tend to keep species richness at the farm level low to facilitate
shade regulation. For instance, most farms in Costa Rica and El Salvador have
only 2 or 3 species in the shade canopy; corresponding figures for two
Nicaraguan sites are 7 or 10 species per farm (Table 9.1). The species used in
coffee shade canopies differ between countries. For instance, bananas (several
species and varieties of Musa, 60–240 stems per hectare) abound in
Nicaraguan coffee plantations but less so in El Salvador and Costa Rica
(10–37 stems per hectare). E. poeppigianaand several Ingaspecies dominate
the shade canopies in Costa Rica and El Salvador, respectively (Table 9.2).
Most species had fewer than five trees per hectare. Similar results have been
reported for Mexico (Marten and Sancholuz 1981).
A total of 25 Ingaspecies are used regularly in the shade strata of neotrop-
ical coffee plantations; in some countries (e.g., Honduras and El Salvador)
most shade canopies include a mixture of three to six Ingaspecies. Ingaspecies
support nectarivorous birds and provide fruit, firewood, and ecological ser-
vices such as water and nutrient maintenance (Wadsworth 1945; Gutierrez
and Soto 1976; Jimenez-Avila 1979; Espinoza 1985; Lawrence 1995; Lawrence
and Zuñiga 1996).- Biodiversity Conservation in Neotropical Coffee Plantations 207
Table 9.1. Plant species parameters in the shade canopy of Coffea arabica
plantations in Central America.
Turrialba, Carazo, Estelí, Santa Ana,
Costa Rica Nicaragua Nicaragua El SalvadorNumber of 1,000-m^229363140
plots sampled
Total plant species 19 36 63 77
richness observed
Maximum expected 19–49 68–94 74–129 92–136
richness (see Colwell
1997)
Modal plant richness 2 (1–8) 7 (1–12) 10 (2–17) 3 (2–14)
per farm (minimum–
maximum)
Stems ha–1(standard 386 (184) 472 (386) 488 (477) 198 (46)
deviation)
Shannon diversity index 1.57 2.06 2.85 3.08
Simpson diversity index 3.0 3.471 8.82 9.87
Alpha diversity index 3.25 11.61 13.4 21.0
(Fisher)
Source:E. Somarriba, unpublished data, 2002.