Zoologia Caboverdiana Vol. 7, No. 2 (2018)
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On track
(2018)
In the second issue of the seventh volume of this journal it almost seems that our prayers expounded in the previous editorial were heard. Fourteen students and researchers from Germany came to explore six of the Cabo Verde Islands and found 18 new records of terrestrial species compared to those listed by Arechavaleta et al. (2005). These new records include the first observations of several species for some of these islands and further new observations for Cabo Verde. We refer to the first article entitled ‘Additions to the checklist of terrestrial biodiversity of Cabo Verde’. We hope this will motivate other research groups to bring more students to this archipelago on field trips.
No bom caminho
(2018)
No segundo número do sétimo volume desta revista quase parece que as nossas preces expostas no editorial anterior foram ouvidas. Vieram da Alemanha 14 estudantes e investigadores consagrados para explorar seis ilhas de Cabo Verde e encontraram 18 novos registos de espécies terrestres relativamente às listadas por Arechavaleta et al. (2005). Estes novos registos incluem as primeiras observações de várias espécies para algumas dessas ilhas e ainda novas observações para Cabo Verde. Referimo-nos ao primeiro artigo intitulado “Adições ao inventário da biodiversidade terrestre de Cabo Verde”. Esperemos que este sirva de motivação a outros grupos de investigação para trazerem mais estudantes a este arquipélago em viagens de estudo.
Cabo Verde is a unique biogeographical region, where by mixing temperate and tropical characteristics an unusually high number of endemic species are reported. Cephalopods are central pieces of trophic networks worldwide, interacting as predator/ prey and competing with fish for ecological niches. We aimed to assess how the topography, prey availability, and predatory pressure of the Desertas Islands shaped the behaviour and ecology of the existing Octopus vulgaris population. Visual census (both underwater and on tidal rock pools) were performed on Santa Luzia Island (20 days) and Raso Islet (eight days). Octopus vulgaris individuals were found only in intertidal areas, during low tide, and mean population morphometry averaged 35.6 ± 10.4 cm (total length) and 175.0 ± 53 g (wet weight). The markedly reduced size of O. vulgaris, only partly explainable by Bergmann’s rule, and exclusion from subtidal areas, appears to have been mainly driven by severe predatory pressure and strong inter-specific competition for limited habitat niches. The induced behavioural and morphometric alterations may be the product of developmental plasticity, or have arisen from deeper genetic alterations, which would portray a potential speciation phenomenon of octopus’ populations residing on Cabo Verde’s Desertas Islands.
Pinna rudis Linnaeus, 1758 (Bivalvia: Pinnidae) has an Atlantic-Mediterranean distribution. Habitat degradation is considered the main cause of population declines in the recent past, raising the conservation status of the species to the category of vulnerable in some places. Population dynamics studies of P. rudis are still necessary to fully understand its conservation requirements. Moreover, new methods of individual data collection should be developed as individuals are highly sensitive to extraction and manipulation. In the present study, we propose a non-invasive method to collect P. rudis morphometric data in situ. For this, we sampled 900 m2 of the sea bed at Matiota Beach on São Vicente Island, Cabo Verde Archipelago, and collected 18 individuals to compute the relationship between shell length and width. The regression equation between the parameters allowed us to estimate the total size of 59 P. rudis individuals obtained from the beach. The non-invasive method adopted allowed determination of the total size of the individuals without removing them from the substratum and, thereby, allowing the comparative study of the species in different zones.
Based on six weeks spent in the field on six Cabo Verdean Islands in September/ October 2016 and 2017, we present 18 additions to the checklist of terrestrial biodiversity of the archipelago (ten arthropods, one bird, two fungi, and five flowering plants). Four of them are first records for Cabo Verde, the others for particular islands. Most interesting are the apple of Sodom fruit fly Dacus longistylus, perhaps actively introduced for biocontrol of the toxic apple of Sodom tree and the additions to the distribution of several bee species of the genera Amegilla, Megachile, and Xylocopa. Our observations indicate that the biodiversity of Cabo Verde is still incompletely known and more fieldwork is needed.