Anthropogenic Correlates of Species Richness in Southeastern Ontario Wetlands

Abstract

We examined the relationship between the richness of four different wetland taxa (birds, mammals, herptiles, and plants) in 30 southeastern Ontario, Canada wetlands and two anthropogenic factors: road construction and forest removal/conversion on adjacent lands. Data were obtained from two sources: road densities and forest cover from 1:50,000 Government of Canada topographic maps and species lists and wetland areas from Ontario Ministry of Natural Resources wetland evaluation reports. Multiple regression analysis was used to model the relationships between species richness and wetland area, road density, and forest cover. Our results show a strong positive relationship between wetland area and species richness for all taxa. The species richness of all taxa except mammals was negatively correlated with the density of paved roads on lands up to 2 km from the wetland. Furthermore, both herptile and mammal species richness showed a strong positive correlation with the proportion of forest cover on lands within 2 km. These results provide evidence that at the landscape level, road construction and forest removal on adjacent lands pose significant risks to wetland biodiversity. Furthermore, they suggest that most existing wetland policies, which focus almost exclusively on activities within the wetland itself and/or a narrow buffer zone around the wetland perimeter, are unlikely to provide adequate protection for wetland biodiversity.

Adjacent land-use affects amphibian community composition and species richness in managed forests in New Brunswick, Canada

“…This relationship has been demonstrated in other studies (Findlay and Houlahan 1997;Knutson et al 1999). Our model suggests that the positive relationship between species richness and wetlands extends 180 m from the pond edge.…”

“…Our model suggests that the positive relationship between species richness and wetlands extends 180 m from the pond edge. The spatial scale of this relationship is smaller than that found by Findlay and Houlahan (1997), who found the positive relationship to extend beyond 2 km from the study site in an agricultural area.…”

Review of the Factors Underlying the Mechanisms and Effects of Roads on Vertebrates

“…These studies shows a reduction in the richness of communities, occurrence, abundance, reproductive success, ecological attributes (e.g., home range, use of space) and life history (e.g., reduction in body size) of numerous species of amphibians, birds and mammals, (medium and large carnivores and herbivores) (Mace et al 1996, Findlay & Houlahan 1997, Nelleman & Cameron 1998, Vos & Chardon 1998, Egan & Paton 2004, Dickson et al 2005, Apps & Mclellan 2006, Fortin et al 2008, Godbout & Ouellet 2008, Liker et al 2008, Crosby et al 2009, Houle et al 2010. In wetland areas, the loss of reptile, amphibian and bird species may reach 20% for each 0.2 km/km 2 increase in roads (Findlay & Houlahan 1997), while ungulates may show a reduction of over 80% in the density of individuals in areas with a road density of 0.6 to 0.9 km/km 2 (Nelleman & Cameron 1998, Apps & Mclellan 2006, Fortin et al 2008.…”

Development of a reference coastal wetland set in Southern New England (USA)

“…These two Narragansett Bay salt marsh studies separated in time by about 25 years suggest that there may be a lag phase of decades before noticeable changes are detectable in salt marsh structure and function due to urbanization. Similarly, in a study of inland wetlands in southeastern Ontario (Canada), researchers demonstrated that land development (i.e., road construction, forest removal) in the 2-km buffer surrounding the wetlands adversely affected the biodiversity of vascular plants, herptiles, and birds, but perhaps more importantly, that there was a lag phase of decades before these changes in biodiversity were evident (Findlay and Houlahan 1997;Findlay and Bourdages 2000).…”