Dados do Trabalho

Título:

IDENTIFYING THE PERSISTENCE AND LOCATION OF THREATS WITHIN THE ENDANGERED MANED THREE-TOED SLOTH (BRADYPUS TORQUATUS: BRADYPODIDAE) DISTRIBUTION RANGE

Resumo:

Human pressures exert critical negative effects on biodiversity, compromising the long-term biota conservation worldwide. Based on leading drivers of species extinction, the International Union for Conservation of Nature (IUCN) is responsible to classify the species into several categories of endangerment. Paramount for this classification scheme is to understand the effects of the multifaceted threats (e.g. residential expansion, habitat loss) on the persistence or decadence of species populations. Yet, there is a glaring lack of information about the persistence and location of these threats, compromising the understanding of different processes that act upon the Earth’s biota, especially across vulnerable biomes such as the Atlantic Forest. This tropical biome presents a chronic process of habitat conversion, but had alarming deforestation rates recently, affecting several endemic species, such as the endangered maned sloth (Bradypus torquatus). Our objective was to identify, pinpoint and analyze the main threat vectors to B. torquatus, across the Atlantic Forest. Based on the species distribution range provided by the IUCN, we identified seven out of 11 threats established by the IUCN, gridded this area in 2 × 2 km cells, and intercepted each-year land use classes from the time-series of the MapBiomas project. Considering a time window of 32 years (1988 - 2020) — correspondent to three-generational intervals for the species —, we gathered the threats' persistence as the accumulation of years that each threat prevails in any cell-grid, deriving a map of the mean of all seven threats. We also derived the threats’ spatial location, corresponding to the position of each threat across the gridded species distribution range. We then binarized all maps of any threat, combining these maps to reach a scale from 0 (none threat) to 7 (all threats in the same grid). Our results reveal that the most common threat within B. torquatus distribution was Pastures (55,633.546 km2, representing 51.5% of species range), and Forestry (4,725.66 km², 4.4% of species range). Whereas pasture areas are decreasing temporally, we identified an increase in urban areas, forestry, and medium-term agriculture. The mean value of threat persistence was 16.9 (± 9.3 sd; range: 0 to 33) years, most of them with a persistence between 20-25 years (18.4%). The mean value of location was 2.5 (± 1.0; 0 to 5). Overall, two threats co-occurs into the vast majority of grid-cells (38.5%). A persistent threat may make it difficult to establish effective mitigation strategies. Both the persistence and the location of the threats were more concentrated in the south metaregion, a highly susceptible territory to an additional decrease in suitable areas due to global changes. This strictly arboreal and folivore species is highly adapted to life in trees. Therefore, our results highlight that the threats' intensity can lead to population isolation and declines, compromising the long-term population viability. Understanding the long-term synergy of threats is quintessential for the development of conservation strategies that curb or minimize the unprecedented human-induced declines in biodiversity.
Keywords: IUCN, threats, endangered species, Pilosa

Financiamento:

Apoio Financeiro: PMS recebe bolsa do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) nº 300893/2022-1. JAB é apoiado pelas bolsas de pós-doutorado da Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) nº 2018-05970-1 e nº 2019-11901-5.

Área

Ecologia