“You can\u2019t pay too much attention to invasives.\u201d That was the message Michael Soul\u00e9, professor emeritus of environmental studies at the University of California at Santa Cruz, brought to the 2007 Hawai`i Conservation Conference, held in Honolulu July 25-27.<\/p>\n
\tSoul\u00e9 was the keynote speaker at the conference, and he gave his audience some tough love. Among the obstacles to restoration he cited was the lack of \u201ca sense of urgency \u2013 the oomph factor.\u201d<\/p>\n
\t\u201cTime is of the essence,\u201d he said, and then provided a quick, if controversial, to-do list: \u201cExtirpate all mammals on islets within five years\u2026 Neuter all cats\u2026 Re-wild offshore islets with native species. Restore areas with conservation easements. Fence all reserves \u2013 the idea of multiple use is a sacred cow, but it doesn\u2019t work.\u201d<\/p>\n
\tPeople involved in this work tended to engage in what he called a \u201cNietzschean fallacy,\u201d preferring genetic purity even at the cost of extinction. \u201cThey say, \u2018don\u2019t mess with Mother Nature.\u2019 But we\u2019ve already messed with her\u2026<\/p>\n
\t\u201cFor some reason, biologists harbor a fear of mixing things up,\u201d he said, \u201ceven though a certain amount of outbreeding is healthy.\u201d<\/p>\n
\t To many in the audience, Soul\u00e9\u2019s message was anathema. To others, especially those involved with inter-situ restoration efforts, he was preaching to the choir.<\/p>\n
<\/p>\n You might think an endangered plant growing on land owned and maintained by the state of Hawai`i\u2019s Department of Land and Natural Resources would have it made in the shade. The DLNR, after all, is the agency within the state that is chiefly responsible for protecting endangered species.<\/p>\n \tThink again.<\/p>\n \tSpecifically, think of Delissea rhytidosperma,<\/i> a shrub once abundant in Kaua`i\u2019s Hanakapiai Valley, now part of Na Pali Coast State Park. Since 2003, says David Bender of the National Tropical Botanical Garden, it has been all but extinct in the wild, eaten or trampled to death by the goats that the Department of Land and Natural Resources does little to control.<\/p>\n \tOr think of ohai (Sesbania tomentosa<\/i>), which once graced the vast dunes of Polihale State Park, on Kaua`i\u2019s western shore. While it may be found elsewhere, Bender says the Polihale population is gone, thanks to the off-roaders and all-terrain-vehicle enthusiasts whose pastime is, apparently, more valued by the state than is the plant\u2019s very existence.<\/p>\n \tFor several years, though, these and other Kaua`i plants have been grown at the National Tropical Botanical Garden in an effort to develop something its conservation director, David Burney, calls \u201cinter-situ\u201d plant conservation. Neither in-situ (in the plants\u2019 recognized range) nor ex-situ (in a garden or greenhouse), inter-situ conservation has been developed by the garden as a means of growing sizable numbers of native plants in almost a farm-like setting. There, with minimal human support (initial irrigation for seedlings, some weeding and mulching), they can flourish and be used later for outplantings in the species\u2019 home range when \u2013 if \u2013 the time comes when that original home range is protected.<\/p>\n \t\u201cIn-situ conservation is the heart and soul, the very best, the only way to preserve ecosystems,\u201d Bender said in a talk at the Hawai`i Conservation Conference. \u201cBut for a subset of critically endangered plants, it\u2019s not enough. It\u2019s too little, too late for a lot of these guys.\u201d<\/p>\n \tThe problem, Bender said, was, \u201cthe political will \u2013 to fence, to remove ungulates \u2013 is lacking.\u201d And although \u201cwe need to work on this front,\u201d he said, in the meantime, inter-situ conservation has an important role to play.<\/p>\n \tBender listed the many advantages of inter-situ over ex-situ conservation. It can protect and establish new plant populations; can allow for maintenance of a given plant\u2019s \u201cevolutionary context\u201d better than ex-situ conservation; provides accessibility for management, monitoring, and research; and does not jeopardize populations that remain in the wild. In some cases, as with the Kaua`i D. rhytidosperma<\/i> and ohai, \u201cinter-situ populations become the only populations left,\u201d he said.<\/p>\n \tThe NTBG collected seeds of D. rhytidosperma<\/i> and a closely related species, Delissea kauaiensis<\/i>, and is now growing them \u201cin semi-natural, inter-situ\u201d conditions at Limahuli Valley and Lawa`i, two of the garden\u2019s properties on Kaua`i.<\/p>\n While purists might criticize the practice, which involves placing plants outside their historic ranges, Bender noted that often, what is known about a plant\u2019s home range is the result of surveys taken in modern times, when the range may have already been substantially reduced by centuries of human-induced alterations. \u201cLots of recorded ranges are less than a hundred years old,\u201d he said, and don\u2019t necessarily match up with suitable \u201cpotential\u201d ranges,\u201d to say nothing of what recent developments in the field of paleo-ecology disclose.<\/p>\n \tThe garden has done much the same thing with ohai. \u201cThe only population at Polihale was in decline for 10 years because of motocross riders and ORVs,\u201d Bender said. \u201cThere was no signage, no fences, no management.\u201d Without vegetation, \u201cthe whole dune habitat could be destabilized.\u201d<\/p>\n \tThe NTBG collected seeds from Polihale and established a population at Lawai.<\/p>\n \t\u201cIn the future, we\u2019ll come to value these inter-situ sites, since they\u2019ll be the only ones left\u201d where some of Hawai`i\u2019s rarest plants can continue to be found, he said.<\/p>\n \tWhile the idea of moving species outside their documented range is generally frowned on, he said, \u201cwe need to get beyond this.\u201d<\/p>\n <\/p>\n <\/b><\/p>\n And Lida Pigott Burney is working to do just that. At Makauwahi Cave, near Maha`ulepu, she and her husband, David, discovered evidence that before the arrival of humans, lowland, coastal vegetation included many of the plants now found only in high mountain areas. As a result of their cave excavations, begun in the early 1990s, the Burneys decided to attempt to grow many of these plants in the prehistoric ranges.<\/p>\n \tThe Burneys obtained a license from Grove Farm, owner of the cave and surrounding land, to use 17 acres of overgrown, fallow cane land for their experiment to see if traditional farm methods and farm machinery could be used in restoration projects.<\/p>\n \tThe Burneys began by disking 5 acres in 2004 and then letting the land lie fallow a year. The next year, they installed an above-ground irrigation system, and planted about 1,000 trees, 83 percent of which survived.<\/p>\n \tEncouraged by their success, they have since established six management units, with each plant inventoried and mapped to allow for close monitoring and easy retrieval, in the event it is needed for outplanting, landscaping, or other use.<\/p>\n \tAs the plants mature, the Burneys use mulch made from native grasses. This, they hope, will not only keep down weeds, but allow the grasses to grow in. The larger trees are also used to provide cover for shade-tolerant understory plants. After just a couple of years, the straight, regimented rows of plantings are softened.<\/p>\n \u201cOne thing about using old farm land,\u201d David Burney said, \u201cis the convenience aspect. Plants laid out in rows can be moved; they become portable plant communities.\u201d To those who might criticize it as unnatural, he has a quick comeback: \u201cNothing is more unnatural than human-caused extinctions.\u201d<\/p>\n <\/b><\/p>\n Line them up end to end, and it\u2019d take three erythrina gall wasps to match up with a mosquito. Despite their tiny size, however, the wasps spread across the Hawaiian Islands like a firestorm in 2005. First detected in the spring on O`ahu, by August, the wasps had landed on Maui. As Art Medeiros of the U.S.G.S. Pacific Island Ecosystems Research Center on Maui explained, it took just 22 days for biologists on Maui to admit defeat and give up on eradication efforts. By fall, the gall-forming wasp Quadrastichus erythrinae<\/i> was on every populated island in the chain, devastating not only native wiliwili (Erythrina sandwicensis<\/i>) but the closely related coral trees, widely used in landscaping. Daniel Rubinoff, a researcher with the University of Hawai`i who is analyzing the DNA of a variety of erythrina gall wasps, noted that in its quick dispersal, the wasp \u201cwas behaving more like a pathogen than an insect.\u201d The rapid invasion of the emerald ash borer or the Asian longhorn beetle on the continental United States \u201clooks like molasses in the freezer\u201d by comparison.<\/p>\n \tAs Medeiros explained, the wiliwili is a keystone species in low-elevation native dry forests. Until the arrival of a seed beetle in 2003, native wiliwili were thought to be one of the most resilient native tree species, Medeiros said, \u201cthriving even adjacent to human habitations.\u201d<\/p>\n \tBut however bad the damage caused by the seed beetle (Specularius impressithorax<\/i>), it was a walk in the park compared to the train wreck caused by the gall wasp. Every tree was infested, and many trees died. The wasps cause leaves to transform into what Rubinoff described as deformed tubers. \u201cNo trees flowered in 2006,\u201d Medeiros said, although \u201csome are flowering this year.\u201d<\/p>\n The state\u2019s response to the invasion was almost as quick as the invasion itself. The Department of Agriculture\u2019s exploratory entomologist, Mohsen Ramadan, was dispatched to Tanzania in January 2006 to search for parasites on gall wasps. Tanzania was selected as the starting point for his work because of the high number of Erythrina<\/i> species found in that country, Ramadan said in his presentation at the conservation conference.<\/p>\n \tRamadan believes that in the remote Tanzanian province of Ngorongoro he found a match for the gall-forming wasp in Hawai`i. The Tanzanian wasp mates with individuals from Hawai`i, he said, and apart from a slight color variation in the hind legs, the two wasps are virtually identical.<\/p>\n \tA year later, Ramadan was in Tanzania again, this time searching for parasites of the gall wasp that might be used for biocontrol. Again, he reported success, finding three ectoparisitoids \u2013 even tinier wasps \u2013 that feed on the larvae and pupae of the gall wasp, keeping the gall wasp populations under control.<\/p>\n \tThe Hawai`i gall wasps have no parasitoids, Ramadan said \u2013 a fact that could account for the devastation wrought when they infest Erythrina trees in the islands. Ramadan described the Erythrina trees in Tanzania as \u201cvery healthy,\u201d with very few galls, even though on the same tree, even on the same leaf, \u201cyou see more than one gall-forming species.\u201d<\/p>\n \tRamadan shipped some of the infested leaves to Hawai`i, where the parasitoid wasps emerged and were studied as possible biocontrol agents. \u201cWe\u2019re confident the parasitoids are host-specific,\u201d he said. His office has now completed studies on one of the parasitoids and is seeking permission to release them into the field.<\/p>\n \tRubinoff, however, is not so sure that the gall-forming wasp in Hawai`i is the same as the one Ramadan discovered in Tanzania. Rubinoff and his colleagues sequenced DNA from 169 wasps from all over Africa, and found no match for the single haplotype that has invaded the Indian and Pacific oceans. The invader \u201cis 10 percent diverged from East African species,\u201d he reported, \u201cand may be a new genus, since 2 to 3 percent divergence is typical for species\u201d within the same genus.<\/p>\n \tRubinoff and colleague Mark Wright, also at the University of Hawai`i, told Environment Hawai`i that they did not receive for testing any of the specific wasps that Ramadan used in his crossing experiments. \u201cTherefore,\u201d said Wright, \u201cwe cannot say with absolute certainty that they are or are not the same as Q. erythrinae<\/i>, but all the Ngorongoro samples we have sequenced were very different from the invasive species of Quadrastichus<\/i>.\u201d<\/p>\n \tWright went on to say that Ramadan\u2019s technique was \u201cnot convincing: he did not actually get the wasps to reproduce; they mated and transferred sperm, but this is not conclusive evidence of them being the same species. Should they have produced progeny, we would have been more supportive of his results, but even that would remain questionable. Bear in mind that lions and tigers (certainly different species) can reproduce with each other in captivity, and indeed do produce viable offspring. But nobody would suggest they are the same species\u2026 In light of this, we are hesitant to accept Mohsen\u2019s results as being in any way conclusive, and maintain that we have yet to find the exact origin of Q. erythrinae<\/i>.\u201d<\/p>\n \tStill, on one point Rubinoff, Wright, and Ramadan are in agreement \u2013 and that is the likely effectiveness of the parasitoid wasp. \u201cThe natural enemies being considered for biological control of Q. erythrinae<\/i> may indeed be very effective,\u201d Wright said in an email to Environment Hawai`i<\/i>. \u201cThere is a school of thought in the field of biological control that \u2018new associations\u2019 among species of pests and parasites may be more effective than \u2018old associations\u2019 (which often coevolve to the point where their populations exist in equilibrium). In theory, because the new association has not had a long history of coevolution, they do not reach equilibrium, and the parasites are able to suppress the pest with great effectiveness.\u201d<\/p>\n Flint Hughes sees a cautionary tale in the zeal of the foresters a century ago to revegetate Hawai`i\u2019s denuded hills with introduced species. \u201cOf the alien woody plants now considered the greatest threats in Hawai`i,\u201d he said, \u201cmore than half were part of systemic plantings in Hawai`i forest reserves.\u201d<\/p>\n \tAnd things can only get worse with the predicted rise in temperature associated with climate change. \u201cWith a 2-degree Centigrade increase, the plant ranges will move to higher elevations. In many cases, the non-natives are already right along the lower edge of the natives\u2019 range, knocking at the door.\u201d<\/p>\n \tHughes used albizia (Falcataria moluccana<\/i>) as an example of good intentions run amok. The fast-growing albizia was intended to prevent erosion and enrich soil through its nitrogen-fixing capacity. But, as illustrated in a photograph of the albizia-invaded walls of Hanalei Valley that Hughes displayed, the albizia can actually foster erosion. The tree grows quickly and is soon unable to support its own heavy limbs. On steep slopes, its shallow roots give way, exposing bare soil and causing small landslides. Far from deflecting runoff, albizia trees can contribute to it. As Dieter Mueller-Dombois has explained, \u201calbizia trees act as funnels for rain water because of their generally upward angled branch system. Because of this, they have a high rate of stem run-off, which is further accelerated due to their smooth bark.\u201d<\/p>\n \tIn fact, Hughes suggested that albizia may have had a starring role in the catastrophic floods in Manoa Valley in 2004. High in Manoa Valley, the trees were planted a century ago by forester Harold Lyon, of Lyon Arboretum fame. While no definitive study was done of the limbs that blocked the Woodlawn bridge, causing so much of the damage to laboratories and libraries at the University of Hawai`i, Hughes speculated that the high winds and heavy rains associated with the flood could easily have caused albizia higher in the valley to shed limbs, contributing to the debris that clogged the bridge. In a plenary talk, Mueller-Dombois noted that the widely publicized crisis that occurred at Lyon Arboretum that same year \u201cwas due mainly to albizia, which were breaking and posing a hazard\u201d not just to the visiting public, but to workers as well.<\/p>\n \tNor is the trees\u2019 nitrogen-fixing quality a good thing, especially in native forests. Hughes\u2019 own work shows that in the wake of albizia incursions, strawberry guava (Psiddium cattleianum<\/i>) is hard on its heels, taking advantage of the nitrogen-enriched soil. Once albizia invades a forest dominated by `ohi`a (Metrosideros polymorpha<\/i>), it is only a matter of time before the `ohi`a dies out. Hughes has observed `ohi`a deaths at nearly 100 percent after albizia invasions.<\/p>\n The same week as the conservation conference occurred, the front pages of Honolulu dailies showed another aspect to albizia, which were being cut down along a major highway in O`ahu. While the white trunks and graceful arching branches make the tree attractive, its beauty is only skin deep. The O`ahu trees were targeted, according to Scott Ishikawa, spokesman for the state Department of Transportation, because their weak branches made them unsuitable for highway landscaping. Many of the cut trees exhibited hollow cores, the result of disease or termite damage.<\/p>\n \tThe Outdoor Circle immediately protested. In response, the DOT backed off and agreed to hold off on further albizia removals along H-2, pending the outcome of talks with the Outdoor Circle and other interested parties.<\/p>\n \tBob Loy, director of environmental programs for the Outdoor Circle, was asked why his organization would object to the removal of albizia.<\/p>\n \t\u201cIt\u2019s not all that simple,\u201d he said. \u201cHere\u2019s the way we look at it. The spot removal of 75 albizia trees in midst of a forest of thousands of the same trees in the exact same area will do nothing to control the problem of their invasiveness.<\/p>\n \t\u201cSecond, regarding safety: we certainly do not oppose the removal of any tree, albizia or any other kind, that poses a threat to human safety. But the fact that albizia trees drop limbs doesn\u2019t mean they\u2019re necessarily a threat to safety. Many of these trees are far enough away from road that under no circumstances, even if the entire tree failed, would any wood reach the roadway.\u201d<\/p>\n \tThe DOT had not shown that the trees posed such a risk, Loy said, and, in light of the DOT\u2019s past actions, he was skeptical of their promise to replant the albizia with native species. \u201cWhat trees are they going to use? Where will they come from? How big will they be?\u201d Loy asked.<\/p>\n \t\u201cThe DOT isn\u2019t always consistent in how it manages roadside landscaping,\u201d Loy continued. \u201cAlbizia, for all their negatives, in their current location, where they don\u2019t pose a hazard, do have some community value, in the absence of anything else. They do beautify the road, and it\u2019s an important road to make sure there\u2019s some scenic beauty.\u201d<\/p>\n \tThere was, finally, a protocol issue. \u201cHad the DOT followed a kind of protocol that made this an open process, where what was being done was shown to be necessary, and had they shared that info with community and organizations like ours, \u2026 this could have been met with a much different level of acceptance.\u201d<\/p>\n <\/b><\/p>\n The arrival to Hawai`i in 2005 of a rust, Puccinia psidii<\/i>, that infests trees in the myrtle family sent shivers down the spines of many Hawai`i botanists. While the rust was known as eucalyptus or guava rust, local botanists worried it could infest `ohi`a as well, the dominant species in Hawai`i forests.<\/p>\n \tLloyd Loope, with the USGS Pacific Islands Ecosystem Research Center in Makawao, was among those who feared the worst. The state Department of Agriculture, Loope noted, renamed the fungus `ohi`a rust.<\/p>\n \t\u201cThat name served to dramatize the true threat of this species of rust to Hawai`i\u2019s dominant native forest species,\u201d Loope said. In hindsight, though, it may have caused some to misgauge the threat, \u201cwhich,\u201d he said, \u201cin retrospect seems not to lie in the billions of spores blowing around these islands but in new strains of the rust\u201d that may hitch a ride to the islands on imports of myrtle family host plants to Hawai`i. So far, \u201conly a small percentage of `ohi`a have been affected\u201d by the rust, Loope said.<\/p>\n \tIn response to that threat, the state Department of Agriculture \u201cis willing to move forward with an interim rule,\u201d barring imports of plants belonging to the myrtle family, Loope said. A risk assessment was submitted to the DOA in April; Loope said he expects the interim rule to be submitted to the Board of Agriculture within weeks.<\/p>\n \tWhile the `ohi`a may have dodged a bullet, not so the unfortunate rose apple (Szygium jambos<\/i>). Loope displayed images from East Maui that showed entire valleys where the foliage of rose apple trees had turned to gray, devastated by rust.<\/p>\n The strain of rust found in Hawai`i differs from those found elsewhere, he said. For example, the rust has been in south Florida for 30 years, where it damages allspice trees, but leaves rose apple untouched. The strain here, so damaging to the rose apple, has no impact on allspice.<\/p>\n — Patricia Tummons<\/p>\n Volume 18, Number 3 September 2007<\/p>\n","protected":false},"excerpt":{"rendered":" “You can’t pay too much attention to invasives.” That was the message Michael Soulé, professor emeritus of environmental studies at the University of California at Santa Cruz, brought to the 2007 Hawai`i Conservation Conference, held in Honolulu July 25-27. Soulé … Continued<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[143],"tags":[],"class_list":["post-1391","post","type-post","status-publish","format-standard","hentry","category-september-2007"],"_links":{"self":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/1391","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1391"}],"version-history":[{"count":0,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/1391\/revisions"}],"wp:attachment":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1391"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1391"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1391"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nNew Approaches to Protection Benefit Kaua`i Plants<\/b><\/div>\n
\nFrom Cane to Conservation: Makauwahi Cave Reserve<\/div>\n
\nHope for Wiliwili Trees Infested with Gall Wasp<\/div>\n
\nAlbizia: When Beauty Is Only Skin Deep<\/b><\/div>\n
\nCautious Optimism on `Ohi`a Rust<\/div>\n