Memorial Park Initial Biological Assessment Memorial Park Conservancy June 20, 2017 Richard Howard
Overview • Purpose • Methods • Results • Discussion • Recommendations
Purpose • Memorial Park is changing
• Drought die-off, hurricane impacts • Planned work w/in the park
• Needed for informed land management • IBA is intended to start filling in biological gaps • Evaluated multiple taxonomic groups throughout a year
Methods • Sample locations • • • •
Nested by habitat type – stratified random sampling Varied in number by taxa – feasibility constraints and initial project focus Intended to optimize identification Excluded areas • • • • •
Polo grounds Golf course Ball fields Houston Arboretum and Nature Center Maintenance yard
Methods • Soil microbes • • • • • •
39 sampling points Soil cores collected at root depth from random locations Ample volume collected for lab analysis Grab samples were manually composited Bacteria, fungi, protozoa, and nematode diversity was analyzed Collected Nov.-Dec., 2016
Methods • Herbaceous vegetation
• 210 vegetation sampling points • Four 1 m2 quadrat subplots per sampling point • Subplot sample collected randomly • Data from subplots were averaged to represent the sampling point • Species richness was calculated per sampling station • Collected for spring summer and fall
Methods • Terrestrial invertebrates
• 37 diurnal and 4 nocturnal sampling points • Techniques
• Diurnal – 15 minute sweep net in 15-foot radius • Nocturnal – checking light traps every 10 minutes for an hour
• Specimens identified in the lab • Diurnal sampling in spring and fall, nocturnal in summer and fall
Methods • Terrestrial reptiles and amphibians
• 5 cover board arrays and 4 drift fence arrays • Cover boards
• 19-20 placed 10 m apart in winter • Checked twice in spring, summer, and fall
• Drift fence arrays
• Three 100-m silt fences with 11 pitfall traps and a central snake trap • Checked daily for one week in spring, summer, and fall
Methods • Aquatic reptiles and amphibians
• 6 sampling locations (3 summer, 3 fall) • Three baited double-throated hoop nets or 2-foot crayfish traps • Traps checked daily for a week • Specimens identified in the field, marked, and released
Methods • Birds
• 52 sampling points • Ten minute unlimited sight distance point counts • Sampled in all four seasons
Methods • Mammals
• 22 sampling stations • Techniques
• Small mammals – 79 traps in a hexagonal configuration; placed in the afternoon, collected the following morning • Medium and large mammals – 2 cameras baited with scent stations, left for one week
• Small mammals sampled in spring, medium and large sampled in summer and fall
Methods • Bats
• 4 AnaBat™acoustic sampling stations in high-use areas • Samplers set on nocturnal mode • Acoustic sampling for at least two weeks • Sampled in spring, summer, and fall
Methods • Aquatic sampling
• 10 sampling points • Techniques
• Benthic invertebrates – 5 minute stream bed sweeps with D-ring net • Fishes – 3 seine pulls with a 30foot seine
• Identified in the field whenever possible • Collected spring, summer, and fall
Soil Results • Fungal diversity was typical of regional soils • Bacterial biomass relatively elevated • Protozoa were generally low • Amoebae • Flagellates • Ciliates
• Nematodes were generally low
Herbaceous Results • Total of 267 species identified • 159 in spring • 166 in summer • 150 in fall
• Average of 12 species per station (SD = 4.97, range 1-30)
Herbaceous Results • Common species
• Southern dewberry, peppervine, woodrush flat sedge, trumpet creeper, American beautyberry, and Virginia buttonweed
• Common invasives
• alligator weed, woodrush flat sedge, Chinese privet, Chinese tallow
Terrestrial Invertebrate Results • Total of 175 species identified • 77 in spring • 128 in fall
• Average of 13 species per station (SD = 8.10, range 1-39) • Common – leaf hoppers, ants • Invasives – fire ant, Africanized bees
Herpetile Results • Total of 27 species identified • 77 in spring • 128 in fall
• Average of 1 species per station (SD = 0.99, 1.08, range 1-4, 1-2) • Common – leopard frog, brown skink, gulf coast toad • Important – alligator snapping turtle, brown anole
Bird Results • Total of 60 species identified • • • •
35 in winter 43 in spring 31 in summer 25 in fall
• Average of 5 species per station (SD = 2.16, range 1-13) • Wide seasonal variation • Notable fall diversity
Bird Results • Common species
• Blue jay, northern cardinal, northern mockingbird • Generally human-acclimated species • Resident species
• Interesting species • Warblers, vireos
Mammal Results • Total of 13 species identified • 3 small mammals trapped • 11 mammals photographed
• Average of 1 species per station (SD = 1.06, range 0-5)
Mammal Results • Small mammals
• Cotton rat, eastern woodrat
• Large mammals
• Coyote, dogs, feral cat, armadillo, opossum, striped skunk, squirrels
• Bats
• Calls from 5 call classes • Likely dominated by free tail bats
Fish and Benthic Invertebrate Results • Species identified
• 19 fishes • 20 benthic macroinvertebrates
• Typical species richness
• 2-3 (SD = 1.61, range 1-10) • 1-2 (SD = 1.44, range 1-4)
Fish and Benthic Invertebrate Results • Common fishes
• Western mosquitofish, sunfishes
• Common benthic invertebrates • Crayfish, backswimmer, water strider
• Invasive species
• Grass carp, armored catfish
Discussion • Community composition consists largely of native flora and fauna • Upland community structure is negatively associated with human impacts • Invasive species are relatively few, but may be ubiquitous • Vegetation community is variable • Climatic events have facilitated changes in structure • High slope areas are generally more depauperate
• Terrestrial invertebrates are typical of the region
Discussion • Herpetiles
• Reptiles and amphibians typical of the region • Alligator snapping turtles identified • May have been depressed by temperatures over sampling year
• Bird community dominated by local songbirds • Mammals
• Small mammal community dominated by two native rats • Large mammal community dominated by native, human-tolerant species • Bat community may be quite diverse
Discussion • Fish and benthic macroinvertebrates
• Communities dominated by species tolerant of poor water quality • Species composition may alter rampantly following flood events
Recommendations • Assess the value of the communities to park users • Plans should account for ecological goals
• What type of park will this be? • How important are these species? • How will the park integrate with the broader ecosystem?
• Maintain as diverse a vegetation community as possible • Maintains richness • Allows species refuge, resident, and migratory habitat • Prevents species invasion
• Rapid assessment techniques may require further detailed work