{"id":335,"date":"2014-04-01T23:32:58","date_gmt":"2014-04-01T23:32:58","guid":{"rendered":"http:\/\/localhost:8888\/EH\/?p=335"},"modified":"2014-04-01T23:32:58","modified_gmt":"2014-04-01T23:32:58","slug":"a-tale-of-two-tracts-success-stories-of-restoration-on-slopes-of-haleakala","status":"publish","type":"post","link":"https:\/\/environment-hawaii.org\/?p=335","title":{"rendered":"A Tale of Two Tracts: Success Stories of Restoration on Slopes of Haleakala"},"content":{"rendered":"
The Nature Conservancy\u2019s Waikamoi Preserve in east Maui has been mostly free of feral pigs and goats for the last two decades. But what has that meant for the native vegetation on the high slopes of Haleakala?<\/div>\n
\nIn 2008, four researchers \u2013 Guy Hughes and Eric Brown, with the National Park Service\u2019s Kalaupapa National Historical Park, and Alison Cohan and Mark White, with TNC \u2013 set out to determine how conditions on the ground had changed since 1994, roughly when the ungulates were removed, by retracing transects that were established then as a kind of \u201cbefore\u201d baseline.<\/p>\n

On the opposite, leeward side of the mountain, over roughly the same period, hundreds of volunteers led by the indefatigable Art Medeiros worked to restore native vegetation on a small, four-hectare tract of what had once been a species-rich dry forest, reduced to mostly non-native grass cover by more than a century of grazing.<\/p>\n

In 2012, Medeiros, with the USGS\u2019 Pacific Island Ecosystems Research Center on Maui, and Erica von Allmen and Charles Chimera, with the Pacific Cooperative Studies Unit of the University of Hawai`i, compared vegetation on the area where the restoration activities occurred to that on a control area, which was nearly identical in vegetation at the time the restoration work began in 1997.<\/p>\n

The results of the two research efforts were published in the January issue of Pacific Science. And, at a time when news from the frontlines of environmental management is generally pretty grim, the two articles are a welcome beacon of hope.<\/p>\n

***<\/strong>
\nAt Waikamoi, Removing Pigs,<\/strong>
\nGoats Makes All the Difference<\/strong><\/div>\n

High on the windward slopes of Haleakala, an area of 428 hectares has been transformed. At the lower elevations, the landscape is characterized by a rainforest, but as the elevation increases, rainfall declines. At the higher elevations, at the time the baseline transects were established, the vegetation was characterized as subalpine shrubline shifting to a grassland, dominated by non-native species, in the highest regions.<\/p>\n

There was no effort to replant species or manage the area in any way other than through the removal of the feral animals. Yet the landscape changes were dramatic. As the authors write, \u201cwe observed a consistent pattern of change on two parallel transects established within a fairly homogeneous subalpine habitat during a relatively short time scale, suggesting that the vegetation community was shifting to an assemblage with a higher abundance of native flora.\u201d<\/p>\n

They suggest three reasons for the shift: first, the release of native species, mosses, and woody species \u201cfrom severe feral animal disturbance;\u201d second, \u201cthe replacement of grass vegetation groups with native shrub, native fern, and lichen groups;\u201d and, third, \u201crelatively drier subalpine conditions\u201d in 2008 than existed in 1994. The first and second reasons are directly related to the absence of the ungulates.<\/p>\n

As to the third, they write: \u201cUnder increasingly dry conditions, one might have predicted a reduction in lichens and bryophytes rather than increases. However, we documented an increase in lichens and bryophytes by more than 300 percent\u2026 suggesting that the changes are likely attributable to ungulate removal.\u201d<\/p>\n

As the lichens and mosses moved into higher elevations, the non-native grasses declined, with grass cover being halved during the study period while \u201cnative ferns increased significantly, and native shrub cover tripled.\u201d In the lower-elevation forested habitat, the authors found, mosses increased in both the understory and upper layers of the forest.<\/p>\n

Their conclusion? \u201cFeral animal removal was effective in promoting native habitat recovery and is recommended as a recovery program strategy that should be prioritized in the largely native areas with a limited presence of invasive alien plant species.\u201d<\/p>\n

<\/b><\/p>\n

* * *
\nIntensive Management
\nPays Off at Auwahi<\/b><\/div>\n

At Waikamoi, managers had a lot to work with. Although the native landscape had been altered by goats and pigs, the most severely degraded areas were adjacent to a relatively intact native ecosystem, which allowed them to be repopulated with native plants naturally.<\/p>\n

At Auwahi, on the other hand, the study site was nowhere near anything that resembled a native forest \u2013 and had been that way for decades. By the 1960s, the authors note, 95 percent of the Auwahi dry forest had been destroyed. Auwahi had become \u201ca museum forest (i.e., a high-diversity forest lacking recruitment).\u201d<\/p>\n

Private landowner Haleakala Ranch attempted to protect the remaining forest by fencing out ungulates \u2013 \u201cwhich unfortunately accelerated kikuyu grass growth and increased tree mortality\u2026 and minimal conservation benefit was realized.\u201d<\/p>\n

In 1997, Medeiros and his volunteers and colleagues began what is described as \u201ca multiphased restoration effort\u201d \u2013 removal of ungulates, suppression of kikuyu grass with herbicides, and the mass planting of `a`ali`i (Dodonea viscosa<\/i>) on four hectares. The `a`ali`i was to function as a nurse plant: hardy, easy to propagate, and quick to grow, it could provide a sheltering habitat for later plantings of rarer species.<\/p>\n

Fifteen years and countless volunteer days later, the difference between the managed tract and the control area was dramatic. In the managed tract, ground cover from non-native grasses was reduced 73 percent. Cover from native species had increased by nearly 58 percent. Vegetation in the control area, meanwhile, was unchanged.<\/p>\n

What\u2019s more, some of the rarest dry forest species had begun to reproduce on their own in the restoration site. Among those was `aiea (Nothocestrum latifolium<\/i>\u00a0Gray). In 2012, the authors note, \u201ctwo wild\u00a0Nothocestrum latifolium<\/i>\u00a0seedlings were discovered \u2026 distant from mature Nothocestrum individuals, apparently the result of seed dispersal by birds, likely the non-native\u00a0Zosterops japonicus<\/i>\u00a0(Japanese white-eye). Though modest, this recruitment represents the only currently known natural regeneration of the species,\u201d which is the sole native host plant for caterpillars of the endangered Blackburn\u2019s spinx moth (Manduca blackburni<\/i>).<\/p>\n

Unfortunately, one non-native tree seems to have taken advantage of the same conditions that favor the natives: the tree poppy,Bocconia frutescens<\/i>. \u201cAlthough most non-native species declined dramatically,\u201d the authors write, the tree poppy recruitment was higher than it was in 1997 and also in the control area. \u201cAs such, weed control in the restoration area \u2026 is currently devoted predominantly to Bocconia\u2026. These results demonstrate the vulnerability of even relatively restored ecosystems to non-native woody species such as Bocconia with the ability to recruit seedlings in shaded or semishaded sites.\u201d<\/p>\n

Along with the need to control weeds is the ongoing requirement to keep out the pigs. The authors relate an incident in 2010 that illustrates the pigs\u2019 predilection for the most endangered plants: that year, \u201ctwo juvenile feral pigs entered the restoration site, their smaller size allowing entry through perimeter fence mesh (since repaired). Before their removal, the pigs apparently searched for and destroyed the entire outplanted population of approximately 100 established Vigna [Vigna o-wahuensis] while minimally impacting other plant species. The pigs excavated the plants, consuming all parts including roots.\u201d Still, two years later, \u201c24 newly emerged Vigna seedlings were recorded in count plots (all near original plantings).\u201d<\/p>\n

The Hawaiian dry forest is one of the most imperiled ecosystems and, \u201cwithout development and implementation of appropriate management strategies,\u201d the authors write, \u201cremaining Hawaiian dry forest will likely disappear within the next century.\u201d But the multiphased approach to restoration of degraded areas \u201coffers one strategy to conserve and restore tracts of dry forests in Hawai`i and perhaps elsewhere,\u201d they conclude.<\/p>\n

For Further Reading<\/i><\/p>\n

See the articles in the January 2014 issue of Pacific Science (Volume 68, Number 1):<\/p>\n

\u201cSubalpine Vegetation Change 14 years after Feral Animal Removal on Windward East Maui, Hawai`i,\u201d by Hughes et al.<\/p>\n

\u201cDry Forest Restoration and Unassisted Native Tree Seedling Recruitment at Auwahi, Maui,\u201d by Medeiros et al.<\/p><\/div>\n

 <\/p>\n

 <\/p>\n

Volume 24, Number 9 March 2014<\/div>\n","protected":false},"excerpt":{"rendered":"

The Nature Conservancy’s Waikamoi Preserve in east Maui has been mostly free of feral pigs and goats for the last two decades. But what has that meant for the native vegetation on the high slopes of Haleakala? In 2008, four … 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":[15,25,36],"tags":[7],"class_list":["post-335","post","type-post","status-publish","format-standard","hentry","category-forests","category-invasives","category-march-2014","tag-patricia-tummons"],"_links":{"self":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/335","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=335"}],"version-history":[{"count":0,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/335\/revisions"}],"wp:attachment":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=335"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=335"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=335"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}