(1) Rock or dead reef 



(a) open marine 



(b) restricted circulation 



(2) Mud, sediment 



(a) grassed covered 



(b) bare 



(3) Sand, sediment 



(a) grass covered 



(b) bare 



(4) Patch reef 



(5) Outer reef 



(6) Forereef muddy sand 



(7) Shoal fringe, restricted 

 circulation 



(8) Reef rubble 



Ecological conditions are 



summarized in Figure 43, present- 

 ed in the previous section on 

 Florida Keys hydrology and water 

 quality. 



9.21 TERRESTRIAL HABITATS 

 OF THE FLORIDA KEYS 



Pinelands 



Like the pinelands of the Ever- 

 glades Keys (Long Pine Key) this 

 community in the Florida Keys is 

 conspicuously associated with out- 

 croppings of the solution riddled 

 Miami Limestone (oolite facies) 

 (Davis 1943) and in the past, the 

 Key Largo Limestone (Alexander 

 1953). Most of the pineland occurs 

 on four of the lower keys: Big 

 Pine, Little Pine, No Name, and 

 Cudjoe. The dominant species are 

 Caribbean Pine ( Pinus elliottii var. 

 densa ) , silverpalm ( Coccothrinax 

 argentata ) , black-bead ( Pithecello - 

 bium keyense ), and the brittle 

 thatch palm ( Thrinax microcarpa ). 

 Wax myrtle ( Myrica cerifera ) is 

 notably infrequent in lower Keys 

 pinelands understory as compared to 

 the mainland. Stopper ( Myrtus 



verrucosa ) , saw palmetto ( Serenoa 

 repens ) , white indigo berry ( Randia 

 aculeata ) , pisonia ( Pisonia rotunda - 

 ta) , poisonwood ( Metopium toxi- 

 ferurn ) , locustberry ( Byrsonima 

 cuneata ) , and the herbaceous plants 



senne ( Cassia keyensis ), acanthus 

 ( Ruellia caroliniensis ssp. ciliosa 

 var. heteromorpha ) , and grasses 

 dominate the understory (Alexander 

 and Dickson 1972). 



The influence of fire on spe- 

 cies composition in Caribbean pine- 

 lands of the Florida Keys is not 

 as well understood as it is on the 

 mainland. Nonetheless, it is known 

 that the Keys have experienced many 

 wildfires and these have undoubtedly 

 served to maintain the pineland and 

 arrest tropical hardwood hammock 

 succession throughout recent time 

 (Alexander and Dickson 1972). The 

 absence of fire and the elimination 

 of pineland by the climax of broad- 

 leaved West Indian species has been 

 documented on No Name and Little 

 Pine Keys (Dickson 1955, Stern and 

 Brizincky 1957), and appears to be 

 the reason why a viable Key Largo 

 pineland has disappeared (Alexander 

 1953). 



Hammocks 



Of the five (5) types of ham- 

 mocks identified by Hilsenbeck et 

 al. (1979) only the tropical hard- 

 wood hammock occurs in the Florida 

 Keys. These hammocks exhibit a 

 greater tropical speciation than 

 those on the mainland, particularly 

 in the lower Keys. Davis (1943) 

 identified two forms of key ham- 

 mocks: (1) coral rock jungle hamm- 

 ocks represented by thicket forests 

 of many tropical trees and a few 

 palms and live oaks ( Quercus virqin- 

 iana var. virqiniana ) confined to 

 the upper Keys; and (2) lower Flor- 

 ida Keys hammocks consisting of 

 thicket forests of tropical trees 

 and shrubs growing in or near rock- 

 land pine forests on limestone, 

 marl, and calcareous sand soils with 

 thatch palms ( Thrinax sp. ) . Only on 

 the Keys, particularly the lower 

 Keys, does Davis (1943) consider the 

 hardwood hammocks as truly tropical. 

 Besides the thatch palms ( Thrinax 



178 



