Negative frequency dependent selection (FDS) had been proposed as a mechanism for the maintenance of the high levels of variability in floral traits of rewardless plants. Thus far the evidence has been equivocal for discontinuous traits. We experimentally tested the FDS hypothesis for continuous variation in flower color of Psychilis monensis, a rewardless, epiphytic orchid of Mona Island, Puerto Rico. P. monensis flowers all year long with a peak in June and July. Plants are self-incompatible. Individual flowers last 9-15 days if unpollinated. Over a 9-month observation of an unmanipulated population, a high percentage of plants showed pollinarium removals (79%) and fruit initiation (63%), but the actual percentage of flowers visited was very low (12%) and final fruit set was as low as the lowest recorded for orchids (2.4%). In a FDS experiment using a Latin Square design, we manipulated flower color in three populations. Over 50% of the variation in either male or female reproductive success was explained by time and site with no significant effect of treatment except as part of a three-way interaction of time x site x treatment. Paired comparisons with the controls gave equivocal results for both male and female measures of reproductive success. Major community changes had occurred during the FDS experiment with flower activity falling dramatically and by the third run of the experiment, only P. monensis was in flower. Coincidentally, the numbers of effective visits increased with time, presumably as pollinators became less discriminating in search of new food resources. Thus, negative frequency dependent selection is either sporadic or non-existent. Reproductive success was statistically related to locality and date, which was reflected in the flowering phenology of the local communities. High natural levels of color variation may be more influenced by drift than selection.

Tropical ecosystems are undergoing unprecedented rates of degradation from deforestation, fire, and drought disturbances. The collective effects of these disturbances threaten to shift large portions of tropical ecosystems such as Amazon forests into savanna‐like structure via tree loss, functional changes, and the emergence of fire (savannization). Changes from forest states to a more open savanna‐like structure can affect local microclimates, surface energy fluxes, and biosphere–atmosphere interactions. A predominant type of ecosystem state change is the loss of tree cover and structural complexity in disturbed forest. Although important advances have been made contrasting energy fluxes between historically distinct old‐growth forest and savanna systems, the emergence of secondary forests and savanna‐like ecosystems necessitates a reframing to consider gradients of tree structure that span forest to savanna‐like states at multiple scales. In this Innovative Viewpoint, we draw from the literature on forest–grassland continua to develop a framework to assess the consequences of tropical forest degradation on surface energy fluxes and canopy structure. We illustrate this framework for forest sites with contrasting canopy structure that ranges from simple, open, and savanna‐like to complex and closed, representative of tropical wet forest, within two climatically distinct regions in the Amazon. Using a recently developed rapid field assessment approach, we quantify differences in cover, leaf area vertical profiles, surface roughness, albedo, and energy balance partitioning between adjacent sites and compare canopy structure with adjacent old‐growth forest; more structurally simple forests displayed lower net radiation. To address forest–atmosphere feedback, we also consider the effects of canopy structure change on susceptibility to additional future disturbance. We illustrate a converse transition—recovery in structure following disturbance—measuring forest canopy structure 10 yr after the imposition of a 5‐yr drought in the ground‐breaking Seca Floresta experiment. Our approach strategically enables rapid characterization of surface properties relevant to vegetation models following degradation, and advances links between surface properties and canopy structure variables, increasingly available from remote sensing. Concluding, we hypothesize that understanding surface energy balance and microclimate change across degraded tropical forest states not only reveals critical atmospheric forcing, but also critical local‐scale feedbacks from forest sensitivity to additional climate‐linked disturbance.