Landscape Structure and Seasonality: Effects on Wildlife Species Richness and Occupancy in a Fragmented Dry Forest in Coastal Ecuador

Abstract

Despite high fragmentation and deforestation, little is known about wildlife species richness and occurrence probabilities in tropical dry forest (TDF) landscapes. To fill this gap in knowledge, we used a Sentinel-2-derived land-cover map, Normalized Difference Vegetation Index (NDVI) data and a multi-species occupancy model to correct for detectability to assess the effect of landscape characteristics on medium and large mammal occurrence and richness in three TDF areas that differ in disturbance and seasonality in Ecuador. We recorded 15 species of medium and large mammals, distributed in 12 families; 1 species is critically Endangered, and 2 are Near-Threatened. The results indicate that species occupancy is related to low forest cover and high vegetation seasonality (i.e., high difference in NDVI between the wet and dry seasons). We believe that the apparent negative effect of forest cover is an indicator of species tolerance for disturbance. The three sampling areas varied from 98% to 40% forest cover, yet species richness and occupancy were not significantly different among them. Vegetation seasonality indicates that more seasonal forests (i.e., those where most tree species lose their leaves during the dry season) tend to have higher mammal species occupancy compared to less seasonal, semi-deciduous forests. Overall, occupancy did not vary between the dry and wet seasons, but species-specific data indicate that some species exhibit higher occupancy during the wet season. This research offers a good understanding of mammal species’ responses to habitat disturbance and fragmentation in TDFs and provides insights to promote their conservation.

Activity patterns of the white-tailed deer (Odocoileus virginianus) in a neotropical dry forest: changes according to age, sex, and climatic season

“…While it is known that the species' daily activity pattern responds to changes in abiotic conditions and varies with age, these responses have predominantly been studied in temperate ecosystems. Despite the species' high occupancy in SDTF (Haro-Carrión et al 2021), their daily activity patterns have not been thoroughly evaluated (but see Sánchez-Rojas et al 1997).…”

Medium and large-sized mammals in a premontane moist forest fragment, Atenas, Costa Rica

“…3). This pattern can be related to changes across space and time that generates a greater heterogeneity of micro-habitats inside a small forest fragment (Basset et al, 2015;Haro-Carrión et al, 2021;Valenzuela & Macdonald, 2002).…”

“…This could be crucial in small fragments (< 30 ha) where opportunities to find food, water, and suitable shelters are limited, especially for large-sized mammals (Crooks 2002;Crooks et al, 2017;Morera et al, 2021). For instance, Ocelots (Leopardus pardalis), Greater Grison (Galictis vittata) and Collared Peccaries (Pecari tajacu) expand their home ranges during the dry season (Dillon & Kelly, 2008;Haro-Carrión et al, 2021).…”

Mammal diversity responses to anthropic, environmental, and seasonal changes within Caatinga seasonal dry forest landscapes

“…A quarter of extant species are threatened and the risk of extinction has increased dramatically (Johnson et al., 2017; Turvey & Crees, 2019) in the last 40 years (Di Minin et al., 2016). However, recent studies have shown that many mammals differ in their level of sensitivity to anthropogenic (Haro‐Carrión et al., 2021; Rios et al., 2022) and seasonal changes (Cruz et al., 2018; Dias et al., 2019; Haro‐Carrión et al., 2021; Miles et al., 2006; Penido et al., 2017).…”

“…Seasonal dry forests are among the most threatened ecosystems in the world due to the fast expansion of anthropogenic activities and vulnerability to climate change (de Oliveira et al., 2012; Haro‐Carrión et al., 2021; Miles et al., 2006). The Brazilian Caatinga is one of the largest and most biodiverse seasonal dry tropical forests in the Americas (Neri et al., 2019), and it is the Brazilian ecosystem most vulnerable to the desertification process (Costa‐Pinto et al., 2023).…”