By Matt Clark
The border wall is a classic example of habitat fragmentation – one of the leading causes of species extinction. As human-created barriers such as highways and walls bisect the land, once intact wildlife habitat patches become fragmented, and less permeable to wildlife movements. One of the insidious consequences of habitat fragmentation is that it creates smaller, more isolated habitat patches and wildlife populations – the negative effects of which may not become apparent for decades. Isolated wildlife populations are prone to more dramatic fluctuations from year to year, are less resilient to natural disturbances, have a higher probability of local extinction, and are robbed of the crucial genetic interchange that keeps wildlife populations healthy. Fragmentation may also preclude access to water sources, seasonally-available food resources, and new territories. The importance of maintaining and/or restoring habitat connectivity is a fundamental principle that has emerged from wildlife conservation sciences in the past two decades.
The border wall is causing habitat destruction, degradation and fragmentation at a regional scale for a wide array of wildlife – creatures that do not recognize arbitrary political boundaries. Numerous cross-border wildlife linkages have already been severed by the wall, and the wall itself is redirecting traffic into adjacent habitats. Clearly, more scientific research is needed to quantify these impacts.
On-the-ground examples:
· 1.9 million tons of dirt is being used to fill Smuggler’s Gulch in southern California in order to construct a wall across this steep canyon. This threatens to increase sediment flows into the ecologically-sensitive Tijuana River Estuary, which provides habitat for four federally-listed endangered birds: the light-footed clapper rail, the California least tern, the least Bell's vireo and the California brown pelican.
· Both deer and javelina have been documented along the wall in the vicinity of the San Pedro Riparian National Conservation Area, apparently unable to cross the border because of the wall.
· A Compatiblility Determination for the then-proposed border wall on the Buenos Aires National Wildlife Refuge concluded the wall was not compatible with the refuge’s mission and regulations, stating: “The barrier would fragment habitat on the refuge, thereby adversely affecting the ecological integrity of the refuge's natural resources…The barrier would adversely affect endangered species (jaguar), migratory birds (pygmy-owls), and important habitats (Arivaca Creek) on the refuge, thereby conflicting with stated management goals for the refuge...” A controversial land swap was orchestrated and the wall was built anyway. Border Patrol recently documented an aggravated mountain lion on the refuge unsuccessfully attempting to get through the border wall to the Mexican side of its habitat.
Buenos Aires National Wildlife Refuge and the Border Wall. Photo courtesy Matt Clark.
· A recent Biological Opinion from the U.S. Fish and Wildlife Service states, “Shifting IA [illegal alien] activity has already occurred in Arizona and California as a result of fence construction or increased CBP [Customs and Border Protection] staffing”. The wall continues to funnel traffic and disturbance into remote, rugged, and ecologically sensitive areas. The Biological Opinion provides 8 documented examples of this phenomenon, some of which are anticipated to negatively impact threatened and endangered species such as the Sonoran pronghorn, jaguar, Mexican spotted owl and Chiricahua leopard frog.
Matt Clark is the Southwest Representative for Defenders of Wildlife.
The border wall is a classic example of habitat fragmentation – one of the leading causes of species extinction. As human-created barriers such as highways and walls bisect the land, once intact wildlife habitat patches become fragmented, and less permeable to wildlife movements. One of the insidious consequences of habitat fragmentation is that it creates smaller, more isolated habitat patches and wildlife populations – the negative effects of which may not become apparent for decades. Isolated wildlife populations are prone to more dramatic fluctuations from year to year, are less resilient to natural disturbances, have a higher probability of local extinction, and are robbed of the crucial genetic interchange that keeps wildlife populations healthy. Fragmentation may also preclude access to water sources, seasonally-available food resources, and new territories. The importance of maintaining and/or restoring habitat connectivity is a fundamental principle that has emerged from wildlife conservation sciences in the past two decades.
The border wall is causing habitat destruction, degradation and fragmentation at a regional scale for a wide array of wildlife – creatures that do not recognize arbitrary political boundaries. Numerous cross-border wildlife linkages have already been severed by the wall, and the wall itself is redirecting traffic into adjacent habitats. Clearly, more scientific research is needed to quantify these impacts.
On-the-ground examples:
· 1.9 million tons of dirt is being used to fill Smuggler’s Gulch in southern California in order to construct a wall across this steep canyon. This threatens to increase sediment flows into the ecologically-sensitive Tijuana River Estuary, which provides habitat for four federally-listed endangered birds: the light-footed clapper rail, the California least tern, the least Bell's vireo and the California brown pelican.
· Both deer and javelina have been documented along the wall in the vicinity of the San Pedro Riparian National Conservation Area, apparently unable to cross the border because of the wall.
· A Compatiblility Determination for the then-proposed border wall on the Buenos Aires National Wildlife Refuge concluded the wall was not compatible with the refuge’s mission and regulations, stating: “The barrier would fragment habitat on the refuge, thereby adversely affecting the ecological integrity of the refuge's natural resources…The barrier would adversely affect endangered species (jaguar), migratory birds (pygmy-owls), and important habitats (Arivaca Creek) on the refuge, thereby conflicting with stated management goals for the refuge...” A controversial land swap was orchestrated and the wall was built anyway. Border Patrol recently documented an aggravated mountain lion on the refuge unsuccessfully attempting to get through the border wall to the Mexican side of its habitat.
Buenos Aires National Wildlife Refuge and the Border Wall. Photo courtesy Matt Clark.· A recent Biological Opinion from the U.S. Fish and Wildlife Service states, “Shifting IA [illegal alien] activity has already occurred in Arizona and California as a result of fence construction or increased CBP [Customs and Border Protection] staffing”. The wall continues to funnel traffic and disturbance into remote, rugged, and ecologically sensitive areas. The Biological Opinion provides 8 documented examples of this phenomenon, some of which are anticipated to negatively impact threatened and endangered species such as the Sonoran pronghorn, jaguar, Mexican spotted owl and Chiricahua leopard frog.
Matt Clark is the Southwest Representative for Defenders of Wildlife.
2 comments:
Construction - or more accurately destruction - begain at Rio Bosque Westlands near El Paso this week. More fragmentation of habitat, more wetlands filled in, more species driven to extinction. A parting shot from Chertoff and the Bush Administration.
LOL. Truly laughable sentiment.
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