Ottoe skipper (Hesperia ottoe) COSEWIC assessment and status report: chapter 13

Hesperia ottoe

Ottoe Skipper – Hespéri Ottoé

Range of Occurrence in Canada:

Manitoba

Extent and area information

extent of occurrence (EO) (km²)

Small, may be 0

specify trend (decline, stable, increasing, unknown)

N/A or likely declining

are there extreme fluctuations in EO (>1 order of magnitude)?

Unlikely

area of occupancy (AO) (km²)

Small, may be 0

specify trend (decline, stable, increasing, unknown)

N/A or likely declining 

are there extreme fluctuations in AO (>1 order magnitude)?

Unknown

number of extant locations

Maximum one site, possibly extirpated

specify trend in # locations (decline, stable, increasing, unknown)

N/A

are there extreme fluctuations in # locations (>1 order of magnitude)?

No

habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitat

Continuing to decline

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.)

One year

number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values)

Unknown, may be 0, but very small if species is extant

total population trend:  specify declining, stable, increasing or unknown trend in number of mature individuals

Unknown, species possibly extirpated from Canada

if decline, % decline over the last/next 10 years or 3 generations, whichever is greater (or specify if for shorter time period)

Unknown, may be N/A

are there extreme fluctuations in number of mature individuals (>1 order of magnitude)?

Unknown for Canadian populations

is the total population severely fragmented (most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange, i.e., <1 successful migrant / year)?

Yes, if still extant

list each population and the number of mature individuals in each

  • Aweme - extirpated
  • Rounthwaithe - extirpated
  •  Spruce Woods Provincial Park - may be extirpated

specify trend in number of populations (decline, stable, increasing, unknown)

Past declines, currently unknown, may be N/A

are there extreme fluctuations in number of populations (>1 order of magnitude)?

Unlikely

Threats (to populations or habitats)

Actual threats: habitat loss and degradation from invasion by exotic plant species and their control (Euphorbia esula is invading Spruce Woods Provincial Park, the last site in Canada where H. ottoe may be extant.)

Potential threats:  habitat loss and degradation due to:

  • conversion to row crops
  • mining for gravel
  • overgrazing
  • controlled burning
  • haying at inappropriate time of year
  • succession
  • habitat fragmentation

Rescue effect (immigration from an outside source)

Low

does species exist elsewhere (in Canada or outside)?

Yes

status of the outside population(s)?

Threatened or in decline

is immigration known or possible?

Highly unlikely

would immigrants be adapted to survive here?

Likely

is there sufficient habitat for immigrants here?

No

Quantitative analysis

Not peformed

Current status

COSEWIC: Endangered (May 2005)

Status and reasons for designation

Status:  Endangered

Status criteria:  B1ab(iii)+2ab(iii)

Reasons for designation: This species has been found at very few locations in the Canadian prairies where it is associated with fragmented and declining mixed-grass prairie vegetation.  It has recently been found at only one location.

Applicability of criteria

  • Criterion A: Not applicable as there is insufficient information on population size and declines.
  • Criterion B:  Meets criterion B1ab(iii)+2ab(iii) for endangered. In Canada, its extent of occurrence and area of occupancy are both very small (EO<<5,000 km², AO<<500 km²), and it possibly exists at one location with continuing habitat decline.
  • Criterion C: Likely meets criterion C2a(i,ii) for endangered. If extant, the total population is much less than 2,500 mature individuals, with a continuing decline inferred based on habitat decline, combined with population fragmentation where no population is likely larger than 250 mature individuals and all individuals are in one population.
  • Criterion D: Likely meets criterion D1 for endangered. There are likely fewer than 250 mature individuals.
  • Criterion E: Insufficient data to perform analysis.

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