Section 3: Summary of overall results
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© Chris Penner, Tall-grass prairie. |
This report represents a huge achievement, by presenting general status assessments for all of Canada's vascular plant species, all of Canada's vertebrate species, and four groups of invertebrates. The largest group assessed was the vascular plants, with 5074 species, demonstrating the commitment of botanists across the country to assessing and conserving Canada's plants. Despite the number and variety of species assessed, this report represents only about 10% of the total number of species that have been described in Canada! The most species rich regions are Ontario (4052 species, Figure 3-1), British Columbia (3628 species) and Quebec (3328 species), due to the variation in climate and geology that provide diverse habitats in which different species can survive. However, the region with the highest diversity (species richness/area) is Prince Edward Island; the region where you can see the highest number of species in the smallest area!
The majority of the 7732 species assessed in this report received Canada ranks of Secure (3541 species, 46%, Figures 3-1 and 3-2). This number varied by species group, ranging from 17% (fishes) to 70% (tiger beetles). Similarly the proportion of species with Canada ranks of At Risk and May Be At Risk ranged from 0% (crayfishes) to 32% (reptiles, Figure 3-3). However, part of the variation in the proportion of species with low or high levels of risk is associated with variation in the proportion of species with Canada ranks of Undetermined, Not Assessed, Exotic or Accidental (e.g. fishes has a large proportion of species ranked Undetermined and Not Assessed, and a correspondingly small proportion of species ranked Secure). Therefore, to get a clearer picture of which species groups are most secure, or most at risk, we can focus just on species with Canada ranks of At Risk, May Be At Risk, Sensitive and Secure (Figure 3-4). This shows that reptiles and freshwater mussels have the lowest proportion of species with Canada ranks of Secure and the highest proportion of species with Canada ranks of At Risk and May Be At Risk. Amphibians also have a high proportion of species ranked At Risk. A similar graph, comparing regional ranks among provinces, territories and ocean regions, shows that the four ocean regions, and especially the Eastern Arctic Ocean region, have relatively high proportions of species ranked At Risk (Figure 3-5).
Exotic species have been introduced to Canada, both deliberately and accidentally, from around the world. In addition, species with regional ranks of Exotic are often native species that have been moved from regions of the country in which they traditionally occur, to regions in which they are not naturally found. Whether from abroad, or from a different part of Canada, Exotic species can cause problems for native species in a variety of ways, including competition for space and resources, predation, hybridization and introduction of new diseases. Most of the species that were given a Canada rank of Exotic in this report are vascular plants (Table 3-1); in fact, vascular plants have the highest proportion of Exotic species of any group covered in this report (Figure 3-6). Crayfishes also have a high proportion of species with Canada ranks of Exotic. However, the species group with the lowest proportion of regularly occurring, native species is the birds, since a large proportion of bird species are Accidental (i.e. do not regularly occur in Canada). The proportion of regularly occurring, native species is higher in the territories than in the provinces (Figure 3-7). This is probably due to a combination of reduced human activity in the north, the harsh climate, which makes it difficult for new species to survive, and the distance from sources of non-native species.
For most species groups and regions, the proportion of species ranked Undetermined or Not Assessed is low, typically less than 10% (Figures 3-8 and 3-9). This shows how much importance was placed on gathering together enough information to allow a true assessment of each species. We hope that this report will encourage more information to be collected on species currently ranked Undetermined or Not Assessed. The fishes, in particular the marine fishes, had a much higher proportion of species with Canada ranks of Undetermined or Not Assessed than any other group. This reflects the difficulty of surveying fishes in remote, off-shore locations. Without information on the status of these species, it is difficult to judge how human uses of the oceans affect ocean ecosystems and species.
One of the important achievements of this report is to update the status assessments of ferns and orchids, freshwater fishes, amphibians, reptiles, birds and mammals. Updates have resulted in the addition of 28 new species to the national list, due to a combination of species that are new to Canada, and taxonomic changes. Just as importantly, 35 species have been removed from the national list, primarily due to taxonomic changes. Updating the national species lists in this way, keeps the general status program and the Wild Species series abreast of the latest scientific knowledge.
Of the 1330 species that were ranked in both 2000 and 2005, the vast majority have retained the Canada rank they were given in 2000 (1164 species, 87%, Figure 3-10). Of the 166 changes that were made to Canada ranks, most were due to changes in process (40%, 67 changes, Figure 3-11) or to new or updated Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessments (33%, 54 changes). Only 10 changes (6%) were wholly or partly due to biological change in species population size, distribution, threats or trends. In total, 39% of changes involved species moving into a rank with an increased level of risk (65 changes), 31% involved species moving into a rank with a reduced level of risk (51 changes), and 30% involved species moving into or out of the Undetermined, Not Assessed, Accidental or Extirpated ranks (50 species). Considering only the species ranked in both 2000 and 2005, changes in Canada rank have had no significant impact on the proportion of species in each general status category.
One of the aims of the Wild Species series is to help COSEWIC prioritize species for detailed status assessments. In this report, three groups that have not yet been covered by COSEWIC have been assessed; crayfishes, tiger beetles and odonates. Thirty-two of the 250 species in these three groups have been given Canada ranks of May Be At Risk (Table 3-1), suggesting that these species may require detailed COSEWIC status assessments. In addition, the general status program has built contacts and relationships with people working on these species groups that will benefit both the general status program, and COSEWIC. In the future we hope that the Wild Species series will continue to assess groups that have not been assessed by COSEWIC, in order to help prioritize species for detailed COSEWIC assessments. However, as the Wild Species program assesses species groups which are not well-known or well-studied in Canada (e.g. grasshoppers and crickets), the proportion of species that receive ranks of Undetermined and Not Assessed is likely to rise.
