Abundance and morphometry changes across the high‐mountain lake‐size gradient in the tropical Andes of Southern Ecuador

Abstract

The number, size, and shape of lakes are key determinants of the ecological functionality of a lake district. The lake area scaling relationships with lake number and volume enable upscaling biogeochemical processes and spatially considering organisms' metapopulation dynamics. These relationships vary regionally depending on the geomorphological context, particularly in the range of lake area <1 km2 and mountainous regions. The Cajas Massif (Southern Ecuador) holds a tropical mountain lake district with 5955 water bodies. The number of lakes deviates from a power law relationship with the lake area at both ends of the size range; similarly to the distributions found in temperate mountain ranges. The deviation of each distribution tail does not respond to the same cause. The marked relief limits the size of the largest lakes at high altitudes, whereas ponds are prompt to a complete infilling. A bathymetry survey of 202 lakes, selected across the full‐size range, revealed a volume‐area scaling coefficient larger than those found for other lake areas of glacial origin but softer relief. Water renewal time is not consistently proportional to the lake area due to the volume‐area variation in midsize lakes. The 85% of the water surface is in lakes >104 m2 and 50% of the water resources are held in a few ones (∼10) deeper than 18 m. Therefore, midlakes and large lakes are by far more biogeochemically relevant than ponds and shallow lakes in this tropical mountain lake district.

Identifying temporal and spatial patterns of diatom community change in the tropical Andes over the last c. 150 years

“…The heterogeneous distribution of the most common diatom taxa with elevation suggest that a variety of mechanisms underlie this threshold (e.g. thermal regime, availability of different substrates, loadings of organic matter, lake morphometry), and these mechanisms warrant examination in future studies (Mosquera, Hampel, Vázquez, Alonso, & Catalan, ).…”

“…Yet, a higher relative abundance of D. stelligera, P. brevistriata and Tabellaria flocculosa were observed in core tops, and a higher relative abundance of Aulacoseira species (A. alpigena and A. ambigua) were observed in downcore samples (Figure 3, Figures S2 and S3). examination in future studies (Mosquera, Hampel, Vázquez, Alonso, & Catalan, 2017).…”

Long‐term limnological changes in the Ecuadorian páramo: Comparing the ecological responses to climate warming of shallow waterbodies versus deep lakes

“…Compared to other regions across the tropical Andes (Barta et al., ), Cajas National Park has a relatively long history of limnological research (Labaj et al., ; Michelutti et al., , ; Miller, Kannan, & Colinvaux, ; Mosquera et al., ; Rodbell et al., ; Steinitz‐Kannan et al., ; Van Colen et al., ). However, most work has overlooked shallow waterbodies despite their abundance and importance to biodiversity, carbon sequestration and as regulators of water.…”

“…Lado de Larga, Estrella Cocha and Apicocha have been documented in Mosquera et al. () as CJ‐162, CJ‐120 and CJ‐083, respectively.…”

“…Similar responses, in both the timing and nature of changes, have now been recorded in lakes elsewhere throughout the tropical Andes (Michelutti et al., , ). However, little is known about the response of shallow waterbodies, which are also prominent features of páramo landscapes and outnumber large lakes (Mosquera, Hampel, Vázquez, Alonso, & Catalan, ). These shallow sites are often fringed by wetlands and represent key contributors to the biodiversity, water regulating capacity and carbon sequestration of the region (Cooper et al., ).…”