New Zealand Journal of Botany abstracts

---

Observations on aquatic macrophytes in 26 northern New Zealand lakes

C. C. TANNER
J. S. CLAYTON
L. M. HARPER

Ruakura Soil & Plant Research Station
Ministry of Agriculture & Fisheries
Private Bag, Hamilton, New Zealand

Abstract The presence, depth ranges, and esti- mated abundance of submerged, emergent, and free- floating aquatic species recorded in exploratory surveys of 26 northern New Zealand lakes are pre- sented. Most of the lakes are small and relatively isolated, being formed in the extensive dune com- plex of the west coast of Northland. Two of the lakes occur in central Northland in valleys dammed by lava flows. Dense fringes of tall emergent sedges (Eleocharis sphacelata and Baumea spp. domi- nant) occurred in most lakes. Native submerged plant communities free of exotic species were recorded in 21 of the surveyed lakes. Chara cor- rallina and C. fibrosa were the most abundant charophytes, occurring in 21 and 18 lakes respect- ively. The endangered species Hydatella inconspi- cua and Myriophyllum robustum were recorded in 5 and 2 lakes respectively. Three exotic species (Elodea canadenis, Egeria densa, and Ceratophyl- lum demerswri), which have come to dominate the submerged vegetation in many other New Zealand lakes, were recorded individually in five lakes. Where present, they formed tall, often monospe- cific growths which displaced native submerged species from mid depths. Characteristics of the vegetation, apparent changes, and the effects of exotic species introductions are discussed.

Keywords Northland lakes; dune lakes; aquatic vegetation; macrophytes; charophytes; exotic plants; adventive plants; endangered species; plant sur- veys; plant distribution; plant invasions

Received 23 December 1985; accepted 23 May 1986
New Zealand Journal of Botany, 1986, Vol. 24: 539-551
0028-825X/86/2404-0539$2.50/0 © Crown copyright 1986

PDF file of entire paper: medium quality (832K); (scanned from paper original: notes about this process)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page