Patterns of Specialization and Faunal Connectivity in the Biomes of the Chimborazo Reserve, Ecuador: A Multivariate Analysis of High-Andean Fauna

The Andes serve as natural laboratories where biomes shape faunal communities into mosaics of habitats prone to fragmentation, making protected areas such as the Chimborazo Reserve (RC) critical refuges in the face of climate change. Based on this premise, patterns of biotic specialization and inter-biome faunal connectivity were evaluated through the ordering and co-scaling of family-level taxa in factorial space. A geospatial design was employed, stratifying the area into 400 ha cells, which were distributed across the high-Andean tundra (T), paramo grassland (G), and Andean forest (F) biomes and selected via simple proportional random sampling. A validated database of 2511 occurrences was compiled for the classes reptilia, aves, mammalia, amphibia, and insecta, comprising a total of 48 families, integrating records from global platforms and field surveys. The resulting matrix of 102 sampling cells (across three biomes) with 48 taxonomic families was analyzed using principal component analysis (HJ-biplot), k-means clustering, and bidirectional biclustering. It was found that Cluster 3 reflected a marked ecotone effect and faunal connectivity between F and G, dominated by generalist families with high evolutionary success such as Thraupidae, Tyrannidae, and waterbirds. In contrast, Clusters 1 and 2 revealed structural discontinuities and high biogeographic specialization in response to abiotic stress in the tundra, isolating taxa adapted to extreme conditions (Tropiduridae, Cricetidae, and Thinocoridae). Biclustering confirmed that the heterogeneity of the terrain mitigates climatic severity at the forest edge, acting as a microclimatic refuge for specialized nectar-eaters (Trochilidae) associated with Chuquiraga jussieui. The zoological structure of the RC reflects a distinct and predictable faunal partition that is strongly influenced by the interaction between the altitudinal gradient and microtopography. The coexistence of zones of diffuse transitions that promote biotic connectivity alongside nuclei of maximum specialization and ecological isolation was confirmed, which is essential for planning conservation measures.