Adaptations of seasonal and temporary wetland communities

Definitions: Seasonal wetlands are nontidal wetlands that are flooded for extended periods in the growing season. Temporary wetlands are nontidal wetlands that contain surface water for brief periods in the growing season.

Intermittent waters – become dry at times of the year that are more or less predictable. Episodic waters – are water-filled on a more or less unpredictable basis.

Characteristics: Lentic waters Lentic waters Closed environment Closed environment Lack of fish Lack of fish Presence of fairly shrimp and Presence of fairly shrimp and tadpole shrimp tadpole shrimp

Winter Winter Verna pools Seasonal marshes Flooded grasslands Playas Spring Desert depressions Rock pools Summer Summer

Invertebrate and plant communities are affected by duration, timing, and frequency of flooding. Adaptations are: Adaptations are: Morphological Morphological Physiological Physiological Behavioral. Behavioral.

Three main evolved strategies for surviving the dry season: Life history modification Life history modification Physiological tolerance Physiological tolerance Migration Migration

#1 Life History Modification Wetland invertebrates exhibit: High powers of dispersal High powers of dispersal Rapid growth Rapid growth Short life-span Short life-span Small size Small size Opportunistic/Generalistic feeding Opportunistic/Generalistic feeding Wetland plants exhibit: Rapid growth/reproduction – (8 to12 weeks) Rapid growth/reproduction – (8 to12 weeks)

Fairy Shrimp 16 day life cycle 16 day life cycle 1/2” – 1” in size 1/2” – 1” in size Feed on algae, bacteria, protozoa, dead tadpoles and mollusks. Feed on algae, bacteria, protozoa, dead tadpoles and mollusks. Easily dispersed by wind or water fowl. Easily dispersed by wind or water fowl.

#2 Physiological Tolerance Synchronous life cycle. Diapause during stages in the life cycle that coincides with drought. Delta Green Ground Beetle Elaphrus viridis Elaphrus viridis

Production of dormant egg and seed propagules: Plants: Wetland plants will germinate with the first Wetland plants will germinate with the first winter rains. winter rains. Grow while the pool is full of water. Grow while the pool is full of water. Flower and set seed as the water Flower and set seed as the water evaporates. evaporates.

Invertebrates: Invertebrates: Wetland invertebrates lay their eggs in the Wetland invertebrates lay their eggs in the sediment. sediment. Development is allowed to occur in the Development is allowed to occur in the absence of water. absence of water. Emergence occurs when the pond floods Emergence occurs when the pond floods again. again.

Benefits of a long-lived egg and seed bank Maintain genetic, species and community diversity. Maintain genetic, species and community diversity. Food for migrating waterfowl and shorebirds. Food for migrating waterfowl and shorebirds. Predator and competitor free environment. Predator and competitor free environment.

#3 Migration Divided into two forms: Active – Requires power of flight. Seen mostly in insects. Active – Requires power of flight. Seen mostly in insects. Passive – used by smaller plant and animal species that are not able to migrate unassisted. Passive – used by smaller plant and animal species that are not able to migrate unassisted.

Active migration Pantala flavescens The Wandering Glider Breeds in temporary ponds, exhibits long-distance dispersal. At emergence adults fly upward and are transported by the wind.

Passive Migration Wind and surface drainage dispersal. Wind and surface drainage dispersal. Transportation by waterfowl. Transportation by waterfowl. Transportation by insects.

Importance of seasonal and temporary wetlands Increased fitness demands lead to greater genetic diversity. Habitat for distinct species that are not found elsewhere. Maximizing the gene pool of species that occur in both temporary and permanent waters.