Species

BackAgabus godmanni Crotch, 1867

Agabus godmanni Crotch, 1867

Azorean predacious diving beetle (English)

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Coleoptera
  • Family: Dytiscidae
EN Endangered
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores

Archipelago(s):
Azores

Reviewer/s:
Danielczak, A.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

Agabus godmani is an endemic species present in Flores, Faial, S. Jorge, Terceira and S. Miguel islands (Azores, Portugal). It has a large extent of occurrence (EOO = ca 17,600 km²) and small area of occupancy (AOO = 136 km²). The species is common and  known from at least five fragmented subpopulations in 10 locations. In the past, the species has probably strongly declined due to changes in habitat size and quality. The main threat to this species is the impact of introduced species and the agricultural activities (landscape transformation, pollution, habitat destruction). Based on Ferreira et al. (2016) the habitat will further decline as a consequence of climate change (increasing number of droughts). Based upon the small area of occupancy and associated decline in extent of occurrence, area of occupancy and habitat quality it is assessed as Endangered.

Geographic Range:

Agabus godmani is an endemic species present in Flores, Faial, S. Jorge, Terceira and S. Miguel islands (Azores, Portugal) (Borges et al. 2010), known from Natural Forest  Reserves of Topo (S. Jorge); Morro Alto e Pico da Sé (Flores), Caldeira do Faial (Faial), Graminhais and Pico da Vara (S. Miguel). The extent of occurrence (EOO) is ca 17,600 km² and the maximum estimated area of occupancy (AOO) is 136 km²

Regions:
Portugal - Azores
Extent of Occurrence (EOO):
17600 (km2)
Area of Occupancy (AOO):
136 (km2)
Elevation Lower Limit:
450 (m)
Elevation Upper Limit:
1200 (m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Azores
Seasonality:
Resident

Population:

The species is rare in all known subpopulations in freshwater areas in several islands (Flores, Faial, S. Jorge,Terceira and S. Miguel islands). A continuing decline in the number of mature individuals is inferred from the ongoing habitat degradation due to human activities (habitat transformation associated to agricultural activities and cattle pollution) and introduced species. This species is assessed as severely fragmented, as it is distributed in isolated freshwater areas in several islands. At least 50% of its population can be found in subpopulations/in habitat patches that are 1) smaller than would be required to support a viable population, and 2) separated from other habitat patches by a large distance. In fact, the species occurs in fragments that are isolated in a sea of pastures and Cryptomeria japonica plantations.

Habitat and Ecology

The species occurs in the freshwater habitats located in native forests of the Flores, Faial, S. Jorge, Terceira and S. Miguel islands (Azores), with an altitudinal range between 450 and 1200 m. Adults and larvae are predators that live in the water column of freshwater systems.

Major Threat(s):

The main threat to this species is the impact of introduced species and the agricultural activities (landscape transformation, pollution by herbicides and pesticides and nutrient loads, habitat destruction). However, we may add to these the impact of climatic changes with major impact on habitat shifting & alteration and droughts (Ferreira et al. 2016).

Conservation Actions

The species is not protected by regional law. Its habitat is in regionally protected areas (Natural Parks of Flores, Faial, S. Jorge and S. Miguel). Degraded habitats should be restored and a strategy needs to be developed to address the future threat by climate change. Further research is needed into its ecology and life history in order to find extant specimens.  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).