Small montane cloud forest fragments are important for conserving tree diversity in the Ecuadorian Andes

Abstract

Montane tropical cloud forests, with their complex topography, biodiversity, high numbers of endemic species, and rapid rates of clearing, are a top global conservation priority. However, species distributions at local and landscape scales in cloud forests are still poorly understood, in part because few regions have been surveyed. Empirical work has focused on species distributions along elevation gradients, but spatial variation among forests at the same elevation is less commonly investigated. In this study, the first to compare tree communities across multiple Andean cloud forests at similar elevations, we surveyed trees in five ridge‐top forest reserves at the upper end of the ‘mid‐elevation diversity bulge’ (1900–2250 masl) in the Intag Valley, a heavily deforested region in the Ecuadorian Andes. We found that tree communities were distinct in reserves located as close as 10 to 35 km apart, and that spatially closer forests were not more similar to one another. Although larger (1500 to 6880 ha), more intact forests contained significantly more tree species (108–120 species/0.1 ha) than smaller (30 to 780 ha) ones (56–87 species/0.1 ha), each reserve had unique combinations of more common species, and contained high proportions of species not found in the others. Results thus suggest that protecting multiple cloud forest patches within this narrow elevational band is essential to conserve landscape‐level tree diversity, and that even small forest reserves contribute significantly to biodiversity conservation. These findings can be applied to create management plans to conserve and restore cloud forests in the Andes and tropical montane cloud forests elsewhere.

Deforestación y fragmentación en las áreas más biodiversas de la Cordillera Occidental de Antioquia (Colombia)

“…La fragmentación se midió a través del grado de cohesión de los píxeles de bosque dentro de una ventana de 3 km x 3 km, donde se observa que la mayoría del área del COA no contiene bosques continuos de este tamaño, es decir, gran parte de los bosques fuera del sistema de AP son fragmentos de menos de 1 km 2 (100 ha; Figura S1d). En términos de la viabilidad de las especies, se puede pensar que estos pequeños parches de bosque no son importantes, pero se ha demostrado que, en los Andes, estos son claves para mantener relictos de poblaciones de especies endémicas o raras, y además facilitan la conectividad entre grandes áreas Biota ColomBiana 23 (1) -2022 | de bosque (Wilson & Rhemtulla, 2018). Es por ello que mantenerlos, y preferiblemente incrementarlos, es un asunto prioritario.…”

Plant community assembly of alpine meadow at different altitudes in Northeast Qinghai‐Tibet Plateau

“…Understanding the mechanisms of species coexistence and diversity maintenance in complex ecological communities is a fundamental question in ecology (Li et al, 2019). Niche and neutral theories offer alternative explanations for the diversity of community species from different perspectives to reveal the community assembly mechanism (Wilson & Rhemtulla, 2018). Niche theory held that every organism has the most suitable environment for survival to choose different balance strategies in different environments (Uchida et al, 2019).…”

Distribution and Community Assembly of Trees Along an Andean Elevational Gradient

“…Montane forests are an ideal system to study gradients in species composition because they eliminate confounding regional scale effects. These forests are also among the most species rich in the world, but consistently remain understudied compared to lowland tropical forests [7,8,11,12,13,14,15]. Montane forests are frequently immersed with clouds and are recognized for their low canopy height, multi-stemmed trees, and high epiphyte abundance [16,17,18].…”

“…Montane forests are frequently immersed with clouds and are recognized for their low canopy height, multi-stemmed trees, and high epiphyte abundance [16,17,18]. They are also known to possess high levels of endemism, due in part to the unique environmental conditions and topography where they are found [7,12,15,19].…”