Species

BackXanthorhoe inaequata Warren, 1905

Xanthorhoe inaequata Warren, 1905

Geometer Moth (English); Traça (Portuguese)

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Lepidoptera
  • Family: Geometridae
LC Least Concern
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores

Archipelago(s):
Azores

Reviewer/s:
Danielczak, A.

Contributor/s:
Nunes, R. & Lamelas-Lopez, L.

Facilitators / Compilers/s:


Assessment Rationale:

Xanthorhoe inaequata is an endemic species present in the islands of Corvo, Flores, Faial, Pico, Graciosa, S. Jorge, Terceira, S. Miguel and Santa Maria (Azores, Portugal) (Borges et al. 2010). It has a relatively small area of ocupancy (AOO = 280 km²) and a large extent of ocurrence (EOO = ca 42,000 km²). The species can be found in native forest fragments, but also in the habitats which are dominated by forest plantations and patches of semi-natural and exotic vegetation, being known from all eighteen Natural Forest Reserves. Based on Ferreira et al.(2016) the habitat will decline as a consequence of climate change. The species is assessed as Least Concern (LC) due to the widespread distribution and high abundance in several habitats, having also a high range of altitude occupancy (10-1400 m).

Geographic Range:

Xanthorhoe inaequata is an endemic species present in the islands of  Corvo, Flores, Faial, Pico, Graciosa, S. Jorge, Terceira, S. Miguel and Santa Maria (Azores, Portugal) (Borges et al. 2010). The species can be found in native forest fragments, but also in the habitats which are dominated by forest plantations and patches of semi-natural and exotic vegetation, being known from all eighteen Natural Forest Reserves: Caldeiras Funda e Rasa and Morro Alto e Pico da Sé (Flores); Caldeira do Faial and Cabeço do Fogo  (Faial); Mistério da Prainha, Caveiro and Caiado (Pico); Pico Pinheiro and Topo (S. Jorge); Biscoito da Ferraria, Pico Galhardo, Caldeira Guilherme Moniz, Caldeira Sta. Bárbara e Mistérios Negros and Terra Brava (Terceira); Atalhada, Graminhais and Pico da Vara (S. Miguel) and Pico Alto (Sta. Maria). The extent of occurrence (EOO) is ca 42,000 km² and the maximum estimated area of occupancy (AOO) is 280 km².

Regions:
Portugal - Azores
Extent of Occurrence (EOO):
42000 (km2)
Area of Occupancy (AOO):
280 (km2)
Elevation Lower Limit:
10 (m)
Elevation Upper Limit:
1400 (m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Azores
Seasonality:
Resident

Population:

The species  is a widespread and high abundant species in native and naturalised vegetation of several habitats of all Azorean islands. The species apparently has currently a stable population, but it greatly depends of the conservation of both native forest fragments and the semi-natural vegetation.

Habitat and Ecology

Xanthorhoe inaequata occurs in several habitats with native and naturalised herbaceous vegetation in the all Azorean islands. We assume that the larvae are specialist herbivores (e.g. Rubiaceae family such as Rubia agostinhoi and Galium spp.); the adult flies from May to August, having probably two generations per year. Altitudinal range: 10-1400 m.

Major Threat(s):

In the past, the species has probably strongly declined due to changes in habitat size and quality, mostly the creation of pastures (Triantis et al. 2010). Currently invasive plants Hedychium gardnerianum are changing some of the areas and decreasing the quality of the habitat. These changes are decreasing the relative cover of endemic plants and changing the soil cover (decreasing the cover of bryophytes and ferns). Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate change (increasing number of droughts and  habitat shifting & alteration).

Conservation Actions

The species is not protected by regional law. Its habitat is in regionally protected areas (Natural Parks of Corvo, Faial, Flores, Graciosa, Pico, S. Jorge, Terceira, S. Miguel and Sta. Maria). Degraded habitats should be restored and a strategy needs to be developed to address the future threat by climate change. It is necessary a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species. A habitat management plan is needed and anticipated to be developed during the coming years. Monitoring every ten years using the BALA protocol will inform about habitat quality (see e.g. Gaspar et al. 2010).