Predicting the Spread of Miconia on O ahu

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Bruno Crawford
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1 Predicting the Spread of Miconia on O ahu Jean Y. Fujikawa HCPO/HIGICC Conference September 25, 2009

2 Introduction Miconia (Miconia calvescens) is a highly invasive tree that has been cited as among the top threats to Hawai i s wet forest ecosystems. The O ahu Invasive Species Committee (OISC), building on the work of its volunteer founders and initial work conducted by the Hawai i Department of Agriculture (HDOA) and Department of Land and Natural Resources (DLNR), has been systematically removing miconia from the southern Ko olau Mountains since What would the miconia situation on O ahu be without those dedicated volunteers, HDOA, DLNR, and OISC? An ArcGIS model was created by OISC to illustrate the rapid spread of miconia had no one acted upon the invasive potential of this species or similarly if systematic control efforts were to suddenly stop. This model incorporates variables such as rainfall, age to maturity, and the dispersal range of seeds by birds to depict the invasive spread of miconia on O ahu.

3 Outline OISC Miconia The Model Without any control Without any future control Why you should care

4 The Oahu Invasive Species Committee or OISC is a voluntary partnership of private, governmental, and non-profit organizations united to prevent new invasive species infestations on the island of Oahu, to eradicate incipient invasive species, and to stop established invasive species from spreading. OISC is concerned with all non-native invasive species threatening agriculture, watersheds, native ecosystems, tourism, industry, human health, or the quality of life on Oahu.

5 Some of OISC s Target Species Miconia Miconia calvescens Coqui Frog Eleutherodactylus coqui Himalayan Blackberry Rubus discolor Beardgrass Andropogon glomeratus var. pumila Fountain grass Pennisetum setaceum Pampas grass Cortaderia spp. Smoke bush Buddleia madagascariensis Tokay Gecko Gekko gecko

7 Miconia (Miconia calvescens)

8 Miconia Originally from South and Central America, miconia was brought to the Pacific as an ornamental plant. Miconia produces 3 million seed 2-3 times a year (Loope 1997). OISC s number one target species Tiny miconia seeds are easily transported by birds and other animals, muddy shoes, vehicles, and equipment. Miconia takes over whole forests, until no other plant species exist. Its large leaves prevent water from reaching the forest floor and soaking into the watershed

9 Miconia in Tahiti Only need to look to Tahiti for a real world example Forms dense monotypic stands Covers ~80,000 hectares or 197,684 acres of Tahiti Displaced native mesic and wet forests The worst invasive species are those that change the environment typically to the exclusion of all other species. The spread of miconia on Tahiti resulted from a single specimen introduced into a botanical garden in 1937

10 Miconia in Tahiti

11 Miconia in Tahiti

12 Miconia Understory in Tahiti

13 Miconia Control on O ahu

14 Miconia Model (Parameters based on literature, OISC data, and computer capacity) Input scenarios No control, initial introduced plants No future control, current plants Miconia matures in as little as 4 years Dispersal distance and number of seeds within 400m from plant: 18* seeds within 1600m from plant: 2* seeds * Note artificially small seed number since miconia produces millions of seeds a year

15 Miconia Model (Parameters based on literature, OISC data, and computer capacity) Clip to coast Clip to rainfall and streams Greater than 1800mm water or next to stream 50% chance of survival per year if water is not optimal Extract impervious surface values Extract slope values

16 Scenario 1: Initial Introduced Plants

17 Scenario 1: Initial Introduced Plants Year 1

18 Scenario 1: Initial Introduced Plants Year 2

19 Scenario 1: Initial Introduced Plants Year 3

20 Scenario 1: Initial Introduced Plants Year 4

21 Scenario 1: Initial Introduced Plants Year 5

22 Scenario 1: Initial Introduced Plants Year 6

23 Scenario 1: Initial Introduced Plants Year 7

24 Scenario 1: Initial Introduced Plants Year 8

25 Scenario 1: Initial Introduced Plants Year 9

26 Scenario 1: Initial Introduced Plants Year 10

27 Miconia controlled by various organizations and volunteers

28 Scenario 1: no initial control efforts Started with one mature miconia per general location of initial plantings Ran model for 10 years Definitely presents a far more miconia rich environment Early control efforts has kept miconia to a manageable level

29 Scenario 2: No future miconia control

30 Scenario 2: No future miconia control Year 1

31 Scenario 2: No future miconia control Year 2

32 Scenario 2: No future miconia control Year 3

33 Scenario 2: No future miconia control Year 4

34 Scenario 2: No future miconia control Year 5

35 Scenario 2: No future miconia control Year 6

36 Scenario 2: No future miconia control Year 7

37 Scenario 2: No future miconia control Year 8

38 Scenario 2: No future miconia control Year 9

39 Scenario 2: 10 years or so out No future miconia control Year 10

40 Scenario 2: no future miconia control Started with miconia controlled the last time each location was visited Ran model for 10 years Definitely presents a far more miconia rich environment Continued control efforts are necessary to keep miconia from overwhelming O ahu s ecosystem

41 Who should be concerned? Many organizations own land or have species of concern in areas that miconia could overrun. Many are already OISC partners.

42 Who else should be concerned? Do you swim, snorkel or surf? Increased runoff could affect nearshore resources. Do you drink water? Miconia s large leaves prevents water from reaching the forest floor and soaking into the watershed to recharge our aquifers.

43 If you live in the following valleys you could soon have a sea of miconia looming above you. Zooming into the area in upper Mānoa Valley indicated by the red box 10 years or so out Kalihi Nu uanu Mānoa Scenario: No future miconia control Year 10 Ka alaea Āhuimanu He eia Waimānalo

44 Mānoa

45 Mānoa with Miconia Model Output

46 Miconia in Tahiti This could easily be Mānoa as the miconia model illustrated. Would you want to live at the base of this miconia infested mountain?

47 Mānoa with Miconia Model Output

48 Summary ArcGIS models can be good outreach tools Early and continued invasive species control is important Everyone is affected by a miconia invasion

2014 Annual Species Management Report

2014 Annual Species Management Report MICONIA Crewmembers conducted 2,726 acres of aerial and 2,657 acres of ground surveys for miconia for a total of 5,383 acres surveyed in 17 watersheds. Watershed Aerial Acres Ground Acres Mature Controlled