Pisonia, with the largest acreage (20.79 ha) and some of the 

 tallest trees (20 m high) on the atoll (PI. 43. Table 1 1 ). In 

 addition, Cordia is well represented: two major groves of 

 Cordia-Toumefortia forest occupy 11.8 ha, 2% of Nake"s 

 area. Extensive pioneer herb mats. Hanked on their inner sides 

 by Tournefortia scrub, occur in the north and east. The 

 remaining Cocos, essentially in the southern quarter, comprise 

 Caroline's second largest coconut grove. 



Birds : Nake, with 80% of Caroline's breeding seabird 

 species, shows a direct correlation between islet size and bird 

 species diversity. Nine species of seabirds breed, all with 

 larger populations (pairs) than previously reported (Clapp & 

 Sibley, 1971a): masked booby (105), brown booby ( 1). red- 

 footed booby (496), great frigatebird (522), lesser frigatebird 

 1 56), brown noddy ( 390), black noddy (8 14), sooty tern (nesting 

 in 1989; Anne Falconer, personal communication), and white 

 tern (1,094). 



2. LONG ISLAND (75.98 ha) (Figs. 30,35,38-41; 

 Pis. 8,13,18,20,28,33,47,58) 



Third largest in area, this longest of motus covers nearly 

 one-third of the atoll's windward side. In the north it is 

 separated from Nake by a narrow channel; from its southern tip 

 a chain of smaller motus extends south along the windward 

 reef. 



Physiography and History : Long — 4.226 m long and 

 330 m wide — is somewhat snake-shaped, with an enlarged 

 northern "head" and attenuated "tail." From a distance its 

 vegetation appears as a series of humps. Long has experienced 

 a fairly complex geological history, noted by the Solar Eclipse 

 Party: "On some of the islands there are spaces void of 

 \ egetation, extending from lagoon to beach, which indicate the 

 existence at a former time of a water separation" (Holden & 

 Qualtrough. 1884). 



At present. Long is composed of five distinct former islets 

 separated by sparsely vegetated channels of coarse sand and 

 coral gravel. Aerial photographs also reveal further, older 

 subdivisions (discussed below). Coalescence and fracturing of 

 the original motus have probably occurred repeatedly. Since 

 erosion proceeds faster on an atoll's windward reefs, providing 

 coral fragments, coralline algae, and pulverized mollusks, il is 

 no surprise that the first series of Caroline's motus to fuse were 

 those facing this rich source of parent material. 



Long's coarse rubble beaches (Pis. 13.20) are a mirror 

 image of those on Nake: southward, the) widen progressively. 

 The swath of unvegetated rubble above high tide line in the 

 upper two-thirds of Long averages S m wide, while in the lower 

 third il is 40 m wide. Unvegetated coral debris accounts for 

 10% of the island's area (Fig. 30). Beachrock, Hanking the 

 windward shoreline for most of its length, is more abundant 

 than elsewhere on the atoll (PI. 58). 



I ong's lagoon Hank is edged w ith submerged sand and silt 

 and is line of the most sheltered parts of Caroline. Sand and 

 rubble deposition off the south point has formed an islet in the 

 lagoon ( Bo'sun Bird |, w Inch could, in the future, coalesce with 

 Long's south point to form a hook. 



An uncommon substrate on Caroline, upraised reef 

 ( makatea > forms a low rampart ( generally < 1 m high ) paralleling 

 the ridge crest inside the vegetation for much of the lower 

 quarter of Long. 



In 1 990 Graham Wragg found some scattered large stones, 

 similar to those of the marae on Nake. located centrally 100 m 

 north of the southern tip of Long, confirming the report of the 

 remains of a smaller marae on Long Island (Holden & 

 Qualtrough, 1884). Wragg noted that the marae was indeed 

 smaller than that on Nake. w ith dimensions approximately 3 m 

 wide by 8- 1 m long. Its orientation appeared to be northeast- 

 southwest. The wall on one end was evidently smashed by 

 storm waves. Only two of the peripheral upright stones were 

 still standing; they were of similar size to those on Nake. The 

 platform was in reasonable condition, with a huge Pisonia tree 

 growing through it. Some rock slabs were large (2 x 2 m). The 

 entire marae was situated within a Pisonia grove, with some 

 Cocos but no Pandanus nearby. We do not know if the nearby 

 coconut grove ( 1 .6 ha) was present before 1 .343 palms ( 20% of 

 the islet's area) were planted in 1918-19 (Young, ca. 1922). 

 The sheltered location and a Pisonia— Cocos forest, which 

 suggests an old clearing, further indicate prior occupation. 



In 1990. G. Wragg also uncovered an RNZAF survey 

 marker just inland of Long's southernmost tip. 



Vegetation : There are 15 plant species (4 trees. 2 shrubs. 

 9 herbs) on Long. 56% of the total flora. Long's variety of 

 habitats, vegetation heights, substrata, and birds make it the 

 most diverse islet on Caroline. Only 3% of its area remains in 

 Cocos. All the atoll's seabirds have bred here. Its ecology is 

 best understood with reference to Figs. 35 and 39—1 1 . 



Within the basic pattern of five coalesced motus. it may be 

 seen that: 



/. From north to south (measured from the midpoint of 

 each former channel) the motus, of divergent size and shape, 

 are approximately 320. 620. 700. 1.840. and 100 m long. 



2. Each former islet, crowned by a Pisonia forest, contains 

 concentric rings of decreasing fertility around its core and is 

 morphologically similar to islets surrounded by water, except 

 that the coarse coral gravel along the former perimeter is less 

 marked. More specifically, beach sands and gravel extend for 

 200-300 m north and south o( the old channels, after which 

 they increasingly accumulate coral rubble, humus, and guano. 



3. The dominant vegetation is Tournefortia, interspersed 

 with 4 patches of taller Pisonia forest and scattered clumps of 

 Cocos md Cordia. Interrupted herb mats parallel the windward 

 coasl and often extend across the island along former channels 

 (PI. 33). Vegetation height varies from 2 cm to 15 m. 



4. Plant species diversity is highest in Tournefortia- 

 Pisonia and lowest in Pisonia forests. 



5. Long's tallest, most mature Pisonia groves (up to L009S 

 Pisonia) occur on the largest of the former islets. The Pisonia 

 forest near the south end (Tr. 10). although healthy, is only 

 12 m tall. This may be due to its impoverished makatea 

 substrate of pitted reef rock barely covered with "soil." Since 

 it lies adjacent to Long's most luxuriant Cocos grove, its land 

 could well have been cleared in 1918-19. with the Pisonia 

 forest taking longer than elsewhere to recuperate. Because tern 



36 



