You may not have seen these crabs in person, but if you walk the beach in the morning, you’ve certainly seen their handiwork. Ghost crabs live in the intertidal zone and after the high tide recedes, they must clear their burrow of the sand the waves washed in. While there are a number of species worldwide, in Hawaii the question is which of the two species is it?
The pallid ghost crab,” Ocypode pallidula, is active day and night and produces a fan shaped formation of sand as it excavates its burrow. The horned ghost crab, Ocypode ceratophthalma, is active at night and forms a small, cone-shaped heap as it excavates its burrow. The latter grows to a larger size and at least for adults, larger burrows, with openings larger than 3″ across, are likely to belong to a horned ghost crab.
One of the outcomes of our participation in the 2018 City Nature Challenge is the realization that a number of group on Maui and the Hawaiian Islands at large are using the platform to get input from citizen scientists about rare, endangered, and invasive species. In this post, I wanted to highlight the DAR Aquatic Invasive Species Team’s iNaturalist project; named, of course, State of Hawaii: Aquatic Invasive Species.
Invasive species, as you might guess from the name, are species that are both not native and are causing a problem. The team has put together a list of thirty-nine aquatic species that are considered invasive in the State of Hawaii. The list below are species of particular interest. A listing of all thirty-nine species, with pictures is available on their iNaturalist guide. Not all of these species are known from all of the Hawaiian islands. Early detection can make a difference between getting rid of these problem species before they spread and having to deal with the ecological (and often economic) havoc they can cause.
If you’d like to find out more about the DAR Aquatic Invasive Species program, there website is here: http://dlnr.hawaii.gov/ais/
- Smothering Seaweed (Kappaphycus/ Euchema sp.)
- Gorilla Ogo (Gracilaria salicornia)
- Leather Mudweed (Avrainvillea amadelpha)
- Hook Weed (Hypnea musciformis)
- Prickly Seaweed (Acanthophora spicifera)
Invasive Marine Animals:
- Orange Keyhole Sponge (Mycale armata)
- Tilapia (Tilapia spp.)
- Upside-down Jellyfish (Cassiopea spp.)
- Peacock Grouper (Cephalopholis argus)
Invasive Freshwater Animals:
- Banded Jewel Cichlid (Hemichromis elongatus)
- Smallmouth Bass (Micropterus dolomieu)
- Green Swordtail (Xiphophorus helleri)
- Convict Cichlid (Archocentrus nigorfasciatus)
- Guppies (Poecilia reticulata)
- Suckermouth Catfish (Hypostomus c.f. watwata)
- Asiatic Clam (Corbicula fluminea)
- Apple Snail (Pomacea canaliculate, P. bridgesi, P. paludosa, Pila conica)
- Tahitian Prawn (Macrobranchium lar)
Invasive Freshwater Plant:
- Giant Salvinia/ Water Fern (Salvinia molesta)
Introduced species sometimes integrate into the fabric of their new home in a way that doesn’t really seem to cause problems for the original residents. Other introduced species – invasive species – do and the Little Fire Ant (aka the Electric Ant) is one of the latter. They are called fire ants because they sting – people, pets, wildlife – they’ve even been reported to have affected hatchling sea turtles! Add to that the fact that their stings are industrial grade – hence the name fire ant – and they’ve even caused pets and livestock to go blind after repeated stings to the eye.
Targeted efforts to eradicate the LFA are ongoing and you can help monitor for the ants. Report them and you’ll get help getting them out of your yard, garden or neighborhood. Check out http://stoptheant.org/ for a pile of resources including a short ~ 30-minute documentary, details about how to monitor for the ant with peanut butter and a chopstick, and if you are a teacher, how to work spreading the word about the LFA with lesson plans all set up for you.
Here is a three-minute lesson on how to test for the Little Fire Ant:
The Maui Invasive Species Committee is joining up with the CNC:Maui this year and we’ll be looking to target species of concern during the event to help MISC’s effort in controlling invasive species on Maui We’ll feature these species in follow up posts, but keep on the look out – and report – any sightings of MISC’s most wanted: the Little Fire Ant, Rapid Ohia Death and the Coqui Frog. You can report sightings of these most wanted and other new and unusuals with the new Hawaii-wide reporting website (and mobile app) 643-pest.org.
You can learn more about other MISC targets species on their website >> here.
We had a great inaugural meetup session at Kealia Pond this past Saturday. It was great to finally connect – in person – with seasoned and hopeful natural historians. We spent a few minutes learning how to use iNaturalist at the newly opened Kealia Pond visitors center. Afterwards, Americorps volunteer Brett led us on a hour-long walk around the pond. We learned about some of the efforts at the NWR to restore the surrounding environment and the challenges faced in keeping the area free of invasives like feral pigs and friendly for the native and visiting waterbirds that rely on Kealia’s wetland environments.
We are excited to be hosting the 2018 City Nature Challenge for the very first time in Hawaii. Our “city” is the entire island of Maui and we are encouraging folks to learn how to use the iNaturalist platform (mobile app and website) to record natural history observations on the island. We’ll use iNaturalist to record as many observations of biodiversity here on the island during the CNC competition – April 27,28,29, and 30 this year. For details about the events, visit our meetup page at https://www.meetup.com/Maui-Nui-Natural-History.