Winter Quarterly Report for Ka’elepulu Wetland, 9-21-04 to 1-15-05

Introduction

On September 21, 2004 I began managing Ka’elepulu Wetland for Cindy Turner and Hugo de Vries. Prior to this the wetland was completely covered with vegetation of a foot or more in thickness except where standing water was deep enough to prevent the growth of batus, pluchia, ai’ai, or mangrove. On the crowns of the man-made islands alien shrubs and trees often stood five feet or more in height.

Vegetation Control

Mangrove
Our highest priority through the month of September was the removal of mangrove from the islands within the moat. Well over five hundred plants were uprooted and killed by drying or were removed from the wetland. In November a community clean-up of mangrove was organized by Bob Burke, who is a consultant living next to the wetland. Although the volunteers worked in many areas of the lake a number of them also went out on the wetland with Hugo, Cindy and their family. Bob, Cindy, and Hugo also worked on a very large stand of mangrove at the far north end of the wetland. They hauled over a thousand pounds of mangrove branches to the Kailua green waste facility from this stand alone. Removal of seedlings that wash up on the wetland is an ongoing part of maintenance.

Island crowns

Clearing of the crowns of the largest islands was the work objective when the mangrove population was under control. This was accomplished with some hand weeding but mostly by a combination of mechanical weed cutting and repeated herbicide treatments. Trees and large shrubs were generally dug out by hand. Ron Walker, a retired biologist, volunteered his expertise, labor, and equipment on a weekly basis.
The islands were numbered in three groups, a diagram is attached. Each grouping has a large island and several smaller islands. The main islands in each group were cleared from October through December. The crown of island one was cleared first. Islands two and three were cleared concurrently after that.
The highest zones of the islands had been colonized by dry land weeds, shrubs, and trees. Pluchia indica was generally found in this zone. The weed species assemblage matches that of the adjacent house site. Approximately 200 koa haole trees from five to eight feet tall were cut from island two and their stumps were poisoned and later dug out. The principal islet of island two also had a thick cover of california grass over an area of around 15 by 40 meters. All dry land trees, shrubs, and grass was ferried out of the wetland by canoe and hauled by Hugo to the green waste facility. The weight of this material was in excess of several tons.
It is important to note that none of the weed populations treated have been eradicated from the wetland. They all have been re-sprouting from seeds after each rainy period since September. All treated areas have been sprayed approximately monthly to prevent the production of more seeds from new plants. Some species are not killed with the glyphosate based herbicide, Aquasafe, applied at 2% strength. Batus is not killed with one treatment of Aquasafe. It resprouts within a month or two from the main stem lower to the ground. First spraying, then cutting ten days later, and then re-spraying emergent growth may be effective but we will know more after a year’s observation. Large numbers of seeds are produced by the remaining stands of batus.

Island fringe and wet areas

When water levels in the wetland were low enough, the low lying zones of batus were cleared to provide shallow wet feeding areas for stilts when water levels are low to moderate. Most of the large mud flats on island one were first sprayed and then cut back after the batus has died back. This was done in successively widening patterns to enlarge the feeding areas from their centers outward to the high ground. No similar large low flats have yet been found on islands two or three but they may exist around some apparent depressions at the northern areas of island three. Work is ongoing there.
Overgrown “fringe” zones between open water and high ground were cleared when water was low enough. When cleared, these zones appear to be open pathways of one to two meters in width during lower water levels. When the water level is high and these areas are flooded they become part of the open bodies of water around the islands. Work continues on these fringe zones when water levels are low.
Island one has the most cleared fringe. Island two has some fringe along the stream side of the area. Island three has some areas cleared around two small islets but as of this writing fringe areas have mostly only been sprayed. Cutting back the batus cannot be done when water submerges the stems near the soil surface and water levels have been high since early December.

Removal of a grass island deposited by the November flood

In November a winter storm caused a flood of the stream entering the wetland. The waters washed down a clump of california grass measuring around six meters by two meters in area. This clump and its root bound sediment was stranded at the edge of island three in less than a meter of water in the stream channel. I removed the above water material and ferried it to shore over an eight week period. It was hauled to the green waste facility.

Predator Control

Trapping for predators began in October. The recommended number of trap days was met or exceeded monthly. Typically traps are set on each principal island for a few days during the month. Roof rats were captured in our four or five Hava-A-Hart live traps on each island. One or two rats were often captured on each island monthly through December.
Traps are checked daily and rats are killed by asphyxiation with automobile exhaust as recommended by a veterinarian.
Occasionally gallinules are caught in the traps. These are checked for injuries and released immediately. All have appeared in good health. No other species have been caught in the wetland although a cane toad was caught in a trap set near the stream on the house lot.

Opala Patrol

Trash Collection

Weekly, the wetland edge is inspected by canoe for trash. When rains have been heavy inspections are more frequent. Toxic or hazardous materials are quantified in weekly reports. Floating inert trash is gathered and disposed of. Hazardous materials are given special handling. Over two hundred cans of spray paint have been collected since the November flood. These seem to be washing down from caches or trash left by those painting graffiti in culverts upstream from the wetland. Some cans have significant amounts of paint in them. All are considered hazardous to the wetland.
We have received help from a couple who live on the stream side of the wetland. Many Mondays they have been going “opala fishing” and they have contributed significantly to the health of the Ka’elepulu Wetland.

Bird Observations

Species of Note

Golden plovers, ruddy turnstones, and solitary sandpipers are migrant wetland species using the wetland. A merganser was reported feeding out in the pond with the coots. A barn owl was seen in the trees along the stream.

Dead Birds

Dead birds were occasionally found. The remains of what was probably a gallinule were found in the Paspalum sp. zone of island two near the road. The cause of its death was unknown but it probably died close to the time of the November flood. Two downy mallard chicks were found together in an area near the stream on island one. These appeared to have died from exposure caused by a heavy rain storm at night. Somehow they were separated from their parent. One dead mature coot was found near the stream bank. The cause of its death was not clear but predation is a possibility.

Breeding activity

Feral Birds

No goose nesting has been observed but the mallards have been active. When nests are discovered the eggs are coated with oil to prevent hatching. Seventy-one eggs have been treated as of January 15th. Despite this effort two clutches of eggs hatched in December from undiscovered nests. The offspring are being monitored in the hope that this may yield information on chick predation and survival.

Native Birds

Three coot nests were built in December and each held five eggs. These nests were flooded during the high water late in December. One nest had in it a dead newly hatched chick indicating that some or all of the eggs there may have hatched before water rose to cover the nest. The fate of the remaining four chicks is not known. A second flooded nest was examined closely and the eggs were located below it in the water. They were dead but embryos were present in four of the five eggs and they seemed normally developed. The third nest was empty but a search for eggs was not conducted because the adults were constructing a new nest higher up on the same nest site.
A gallinule nest was found in the Bulboshonus sp. stand nearest the stream on island three. It was empty but appeared recently made. Male gallinules are known to construct multiple nests for females in their territories.
No stilt nesting activities have been observed but the birds frequent the dry island crowns and occasionally rest in a posture that mimics nesting. Egg sized pebbles have been placed in small mounds in places the stilts may favor as nest sites. These pebble sites are on the highest areas of the islands.


Submitted,
Larry Abbott 1/20/05