Revista Captar: Ciência e Ambiente para Todos

Effects of the invasion of riparian forest by Acacia spp. trees on leaf litter decomposition in streams

Verónica Ferreira, Ana Pereira — Wed, 28 May 2025 00:00:00 +0100

Streams depend on riparian forests (for example, as a source of plant detritus that sustains aquatic communities), therefore, they are susceptible to changes in the species that compose them. The riparian forests in central Portugal are threatened by invasive species, including species of the Acacia genus that have characteristics distinct from those of native species. In recent years, several studies have been carried out in streams of Serra da Lousã to understand what effects (if any) the invasion of riparian forests have on aquatic communities and processes. Here we report some results relating to the comparison of the decomposition of plant detritus in three streams in forests with native species and three streams in forests invaded by Acacia spp. Invasion can slow the microbial decomposition of plant detritus, and consequently the recycling of nutrients, mainly by altering the type of detritus entering streams (which are more recalcitrant as a result of the greater contribution of invasive species). Increased concentrations of dissolved nutrients in the water had a small stimulatory effect on detritus decomposition and the access of fragmenting macroinvertebrates mitigated differences in detritus decomposition between stream types. The effects may worsen as the extent of the invasion increases.

Biodiversidade subterrânea de Portugal: de deserto biológico a hotspot de classe mundial

Ana Sofia P. S. Reboleira — Wed, 04 Jun 2025 00:00:00 +0100

Subterranean biodiversity is typically dominated by invertebrates, among which arthropods are the most diverse group of animals. In the vast, inaccessible immensity of subterranean ecosystems, caves provide access to tiny windows for observing the composition and functioning of these habitats. Portugal was considered a country poor in cave diversity, however, the advancement of multidisciplinary research in the last two decades has allowed it to achieve the status of a world-class subterranean biodiversity hotspot. The incomparable diversity of subterranean arthropods that inhabit the caves of the Algarve, made up of species already considered iconic at an international level. This article presents a global perspective on Portugal's subterranean biodiversity, as well as the unique characteristics of Portugal's caves and other subterranean ecosystems.

Estudo das populações de pequenos mamíferos através da análise de egagrópilas de coruja-das-torres (Tyto alba)

João Soares Carrola, Sofia Bettencourt, Hélia Vale-Gonçalves, Rafael Ferreira — Mon, 23 Jun 2025 00:00:00 +0100

The study of small mammal populations can be carried out through direct methods involving their capture through traps, and indirect non-invasive methods such as camera trapping, prospecting and collection of signs of presence and analysis of barn owl's regurgitated pellets. The barn owl (Tyto alba) is a nocturnal bird of prey with a global distribution, with the exception of the Arctic regions. This species feeds mainly on small mammals that are ingested whole; the bone structures and fur are not digested during the digestive process and are later regurgitated in the form of an ovoid mass, called an regurgitated pellets. The content of the pelletss contains all the undigested structures of the prey and the identification of the species of small mammals is carried out through their teeth. The analysis of the barn owl's diet reflects the diversity and abundance of small mammals captured in its hunting territory, and is a valuable and widely used method for estimating the relative abundance of prey in a given region. There are numerous species of small mammals that can be studied in northern Portugal, namely the white-toothed shrew (Crocidura russula) and the red-toothed shrew (Sorex granarius) from the order Soricomorpha, and the blind mouse (Microtus lusitanicus), the Portuguese field mouse (Microtus rozianus) and the Cabrera mouse (Microtus cabrerae) from the order Rodentia. The populations of small mammals between the different bioclimatic regions of Portugal are important for studying rodent populations and evaluating conservation strategies that consider the climatic and environmental particularities of each region. Protecting the natural habitats of regions is crucial to maintaining biodiversity and ensuring the survival of species, in a logic of sustainable development.