DOI: 10.5061/dryad.wpzgmsbx7
title: Data from: flamingos as ecosystem engineers: flock size and foraging behaviors linked to nutrient availability

description: In wetland ecosystems, birds play a crucial role in nutrient cycling
 through various activities such as excrement deposition, sediment
 disturbance during foraging, and utilization of mud and vegetation for
 nesting. Particularly noteworthy are species exhibiting colonial breeding
 or high sociability, as they can significantly influence waterbody
 communities and act as ecosystem engineers in these habitats. Flamingos
 (Phoenicopteridae) possess all these characteristics, making them
 potential ecosystem engineers. In this study, we aim to test the
 hypothesis that Chilean Flamingos (Phoenicopterus chilensis) exert such
 effects on an important non-breeding wetland. Moreover, we seek to
 elucidate the underlying reasons for these effects and their relationship
 with flock size and foraging behavior. To accomplish this, we conducted a
 year-long study on the flock of Chilean Flamingos at Lagoa do Peixe
 National Park in southern Brazil. We collected environmental and
 behavioral data, including nitrogen, phosphorus, and dissolved oxygen
 levels, water turbidity, salinity, and temperature, from areas both with
 and without flamingos. Our findings suggest a significant role of Chilean
 Flamingos in maintaining the nutrient cycle within wetland ecosystems.
 This is attributed not only to the high levels of guano deposition, but
 also to the bioturbation caused by their foraging behaviors. Furthermore,
 we observed a significant correlation between flock size, the mean
 duration of foraging behaviors, and the magnitude of these effects. This
 study points the likely effects of flamingos to wetlands ecosystems,
 emphasizing the intricate interplay between these birds and their habitats
 and highlights the importance of conserving both the species and their
 ecosystems.
description: Between October 2021 and September 2022, a series of monthly
 field procedures and data collection endeavors were carried out in the
 Barra and central regions of Lagoa do Peixe National Park, covering an
 approximate area of 1500 ha. The Chilean flamingo flocks were located
 using an active search strategy during each field excursion, in
 collaboration with park personnel. Upon locating a flock, behavioral
 observations were conducted utilizing the Focal Animal method. The method
 involved deliberately selecting an individual for continuous observation
 over a period of five minutes. To mitigate sampling bias, we endeavored to
 select foraging animals that were at a considerable distance from
 previously sampled individuals whenever feasible. Detailed notes were made
 regarding each behavior exhibited by the focal individual, including the
 duration of each behavior, with particular emphasis on foraging behaviors.
 Behaviors were also classified into two types: events and states. Events
 are brief, often instantaneous behaviors that occur momentarily, while
 states are behaviors that last for a significant duration and often
 involve more conspicuous or continuous movements.
 Observations were facilitated using binoculars, supplemented
 using a professional photographic camera when feasible. Adherence to a
 pre-established habituation period of 30 minutes before the commencement
 of observations, along with maintaining a minimum distance of 200 m from
 the observed flock, served to mitigate potential observer biases that
 could otherwise influence data collection. To mitigate single observer
 bias, a subset of behavioral videos was analyzed using the software BORIS;
 we then compared the measurements between field observations and video
 analysis, to assess the reliability of the data. In addition, the total
 number of Chilean flamingos within the observed flock was recorded during
 the study. Following behavioral observation of each
 foraging Chilean flamingo flock within a 500-meter radius, we proceeded to
 collect samples of 100 mL of water from the lagoon (called
 F<sub>0</sub> samples). The samples were taken directly at the
 points where the foraging flamingos were previously observed, and the
 500-meter radius ensured that we did not pseudo-replicate the same areas
 twice, avoiding any sampling bias in further statistical analysis. This
 sampling process strictly adhered to recommended methodologies for
 collection and preservation outlined by the South America Flamingo Census.
 Concurrently, a control sample (C<sub>0</sub>) was obtained
 from a location at least 2 km distant from the original sampling site, in
 a suitable foraging area of these animals but devoid of any flamingo
 presence. Subsequently, on the same day, both the initial sampling point
 and its corresponding control point were revisited and resampled after an
 interval of three hours, following the departure of flamingos from the
 initial area (called F<sub>3+</sub> and
 C<sub>3+</sub>, respectively). This methodology ensured the
 acquisition of paired samples, at two distinct points in time and space,
 with both temporal and spatial controls, helping us determine whether
 changes in the lagoon were related to the presence of flamingos or caused
 by external factors. Sampling sites where flamingos remained in the
 initial area after the three-hour period, or control points where
 flamingos were present after the same duration, were excluded from the
 analysis. The primary objective of this sampling regimen is to enable
 comparative analysis and measurement of nutrient levels, verifying whether
 flamingos indeed have effects on the areas, and if these effects persist
 over time. Each water sample underwent analysis to
 determine the concentrations of dissolved oxygen
 (O<sub>2</sub>), total nitrogen
 (NO<sub>3</sub><sup>-</sup> and
 NO<sub>2</sub><sup>-</sup>), and phosphorus
 (PO<sub>4</sub>). Analysis was conducted employing a
 photocolorimetry technique, wherein specific reagents were introduced into
 the solution, forming chromogenic reactions with the target molecules.
 This results in characteristic color changes directly proportional to the
 concentration of the respective molecules. The intensity of coloration was
 subsequently compared against a known quantity standard curve,
 facilitating the precise quantification of the targeted molecules within
 the water samples obtained from the lagoon, in mg/L. A similar process was
 utilized to measured water turbidity, where the water sample was
 homogenized and image analysis was employed to determine the level of
 turbidity in the sample, expressed in NTU (Nephelometric turbidity units),
 based on a known standard curve. To ensure the integrity of results,
 analyses were promptly executed following sample collection, within the
 shortest possible time frame. In addition to nutrient analysis, on-site
 measurements of salinity (expressed in parts per thousand) and water
 temperature (in degrees Celsius) were conducted utilizing a calibrated
 multiparameter meter by Akso.
description: # Data from: flamingos as ecosystem engineers: flock size and foraging
 behaviors linked to nutrient availability
 [https://doi.org/10.5061/dryad.wpzgmsbx7](https://doi.org/10.5061/dryad.wpzgmsbx7) Raw data were collected during field procedures on environmental variables of the lagoon, including the flock size and the mean duration of foraging behaviors of Chilean Flamingos at Barra. The data were separated into four different groups: F0 for areas with flamingos present; F3+ for areas where flamingos were foraging 3 hours later; C0 for control areas with no flamingos; C3+ for the previous control areas 3 hours later. Variables recorded include Nitrogen (Nitro), Phosphorus (Phos), Dissolved Oxygen (Oxi), Turbidity (Turb), Salinity (Sal), Water Temperature (Temp), Flock Size (Fsize), Mean Duration of Foraging Behaviors (Mdur). NA indicating data not applicable.