Defining endemism levels for biodiversity conservation: tree species in the Atlantic Forest hotspot

Abstract

Endemic species are essential for setting conservation priorities. Yet, quantifying endemism remains challenging because endemism concepts can be too strict (i.e. pure endemism) or too subjective (i.e. near endemism). We use a data-driven approach to objectively estimate the proportion of records outside a given the target area (i.e. endemism level) that optimizes the separation of near-endemics from non-endemic species. Based on millions of herbarium records for the Atlantic Forest tree flora, we report an updated checklist containing 5062 species and compare how species-specific endemism levels match species-specific endemism accepted by taxonomists. We show that an endemism level of 90% delimits well near endemism, which in the Atlantic Forest revealed an overall tree endemism ratio of 45%. The diversity of pure and near endemics and of endemics and overall species was congruent in space, reinforcing that pure and near endemic species can be combined to quantify endemism to set conservation priorities.

Climatic distribution of tree species in the Atlantic Forest

“…These species that tolerate colder and drier conditions were small subsets of the analyzed pool rather than distinct sets of species with occurrence restricted to environmental challenging conditions because of their broader climatic range. However, the observed nested structure in species incidence had a relatively low value, evidencing that tree species associated with colder (e.g., in subtropical forests) and drier (e.g., in more seasonal forests) conditions are small subsets of the flora also present in warmer and moister tropical forests (Oliveira-Filho et al, 2013), which are richer in species and endemisms (Lima et al, 2020). Nested metacommunity structure was previously evidenced for trees either in a similar spatial scale (i.e., including distinct forest types across the Brazilian Atlantic Forest) or in smaller scales (within each forest type), but the nested structure was not perfect as clumped species Temperature is a relevant driver of forest tree species distribution.…”

“…The Atlantic Forest extends across Brazil's eastern coast and reaches more continental areas in northeastern Argentina and southeastern Paraguay (5-33° S latitude and 35-57° W longitude; Figure 1). The Atlantic Forest has strong gradients of rainfall (annual means varying between 500 and 3000 mm) and temperature (annual means between 10 and 25 °C), which is attributed to its large variation in terms of forest structure, species richness, and composition (Oliveira-Filho et al, 2006), with high alpha and beta diversities of tree species (Bergamin et al, 2017), as well as high tree endemism levels (Lima et al, 2020).…”

Plant Communities Associated with Egyptian Endemic Flora

“…64, No.1 (2024) YASSIN M. AL-SODANY et al of habitat specificity (Boakes, 2010;Beck et al, 2014;Fithian et al, 2014). An endemic species is defined as a species restricted to a particular geographic region due to many factors such as isolation, and response to abiotic conditions (Lima et al, 2020). It has special importance since they inhabit particular habitats that are restricted to a specific area due to climate change or natural environment destruction (Carmona et al, 2019).…”

Authentication, Micromorphology and Ultrastructure of Pollen Grains and Seeds of Endemic Taxa in Saint Katherine Protectorate, South Sinai, Egypt

“…The endemic taxa inhabit particular habitats restricted to a specific area due to factors such as isolation, climatic changes or urban development. Such species were often endangered, so it is essential to conserve them (Brooks et al 2006;Lima et al 2020). Egypt is divided into four geographic regions; Nile, Western Desert, Eastern Desert and Sinai Peninsula.…”