Weaver news

Weaver Wednesday 3 [243] - Range changes [6]: Spectacled Weaver

2017-02-08 (766)

gravit8 Weaver Wednesday 3: range changes in S Africa (species text)

Spectacled Weaver Ploceus ocularis

Spectacled Weaver, Range-change map between SABAP1 (1987-1991) and SABAP2 (2007-current).
Red, orange and yellow = cells with very large, large, and small relative decreases
Blue, dark green and light green = cells with very large, large and small relative increases.
Cells = quarter-degree grid cells; Only cells with at least 4 checklists in both SABAP1&2 shown. All cells had this species recorded in SABAP1 or in SABAP2 or in both (more about interpretation at Biodiversity Observations 7.62: 1-13).

Spectacled Weaver
Spectacled Weaver,
figure from Birdpix

Range changes in SA

Range change summary
More 4 lists 30 lists
increases n % n %
Decrease 108 22 37 14
Tiny change 116 23 76 28
Increase 266 54 158 58
Total 490 100 271 100
In South Africa the Spectacled Weaver has more grid cells with increases in reporting rate than cells showing decreases, between SABAP1 (1987-1991) and SABAP2 (2007-). Not shown in this map is current SABAP2 distribution which shows that the core of the range of the Spectacled Weaver in South Africa as coastal KwaZulu-Natal; there is good SABAP2 coverage in the Kruger National Park but the Spectacled Weaver occurs at a low reporting rate there.

The points below match the points on the map above.

Areas with very large increases include:
1. Eastern Cape.
2. KwaZulu-Natal.
3a,b,c. The western edge of its range in South Africa (other than the western edge in the Eastern Cape).

Large decreases appear to have occurred:
4. The western edge in the Eastern Cape.

Range changes elsewhere

Equatorial Guinea: at Río Muni, appears to be addition to country list (Demey 2015b).