Wetlands

A wetland can be a marsh, swamp, bog, or fen. What all wetlands have in common is that they are an area that is inundated (water covering the soil) for several days in a row throughout the year, including during growing season. Comparable to rain forests and coral reefs, wetlands offer an immense variety of species and are highly productive ecosystems. Wetlands provide important habitats like nesting areas. They are a natural filtration system that aids in filtering storm water runoff before entering larger bodies of water, and they act as a buffer between land and natural water sources. Wetlands have a complex and dynamic food web that attracts many animal species for all or part of their life cycle. This ecosystem is a vital part of cycling matter and the energy flow necessary to maintain the health of surrounding land and ocean ecosystems.

A Study on Spoonbill Chick Growth and Energy Requirements

A study published in 2019 analyzed and quantified the total energy required for spoonbills to nest successfully in a wetland. The purpose of this study was to provide the previously unknown data so that wetlands and water could be better managed. Nesting birds provide a vital energy flow throughout wetlands and are often referred to as bio-indicators. If food availability for nesting spoonbills is decreased there will be a lower chick survival rate. This could occur if water levels fall and result in a loss of food resources and foraging opportunities. These would lead to adult or chick starvation and/or nest abandonment. Before this study there was a limited understanding of how much food, energy or foraging habitat was necessary to prevent chick starvation and safeguard sustainable recruitment and population size. The daily energy requirement for parent birds is doubled while raising young. It was emphasized that while there are no conservation concerns for this species, a population decline would arise from changes in flooding regimes and loss of resources. This study calculated the spoonbill chick biometrics and energy requirements from birth to independence.

Results

It was found that spoonbill chicks required 71,290 kJ of energy from hatching to independence. Using prey energy values from previous research, a nesting event of 1,000 nests producing an average of three chicks per nest would require ten metric tons of their preferred prey -freshwater crayfish- to support the chicks from hatching until independence. It was unclear if these values including the energy requirements for the parents before and during nesting. The knowledge gaps regarding growth and energy requirements of spoonbills were filled with the creation of the first growth model for spoonbill chicks and the predictive energy models of wetland chick energy requirements. This study was able to make predictions crucial for assessing spoonbill needs while breeding in terms of wetland energy flow. These predictions could be a part of future ecological models for managing wetland fish populations.

Wetland Management

Water management interventions and actions that focus on promoting food availability and sustainability will aid in maintaining sufficient reproduction, recruitment and survival of spoonbills. Examples of management include staggered watering of a series of wetlands within the foraging range of the nesting sites. This would lead to successional changes in vegetation and prey that would provide a range of prey options and foraging habitats for nesting birds. Another example is taking vegetation management actions such as removal and control of invasive weeds and appropriate wetting regimes. Furthermore, minimizing toxins and poisons that come from pesticides and herbicides on water birds and their prey can help promote a healthy wetland environment and lead to successful nesting for spoonbills and all other nesting wading birds.

Reference

O’Brien, L., McGinness, H.M. Ibis and spoonbill chick growth and energy requirements: implications for wetland and water management. Wetlands Ecol Manage 27, 725–742 (2019). https://doi-org.esearch.ut.edu/10.1007/s11273-019-09689-w