Environmental Management

, Volume 45, Issue 5, pp 1076–1095

An Assessment of Land Conservation Patterns in Maine Based on Spatial Analysis of Ecological and Socioeconomic Indicators

Authors

    • School of Biology and EcologyUniversity of Maine
  • Robert J. Lilieholm
    • School of Forest ResourcesUniversity of Maine
  • Jill Tremblay
    • School of Forest ResourcesUniversity of Maine
  • Timothy Glidden
    • Maine State Planning OfficeLand for Maine’s Future Program
Article

DOI: 10.1007/s00267-010-9481-7

Cite this article as:
Cronan, C.S., Lilieholm, R.J., Tremblay, J. et al. Environmental Management (2010) 45: 1076. doi:10.1007/s00267-010-9481-7

Abstract

Given the nature of modern conservation acquisitions, which often result from gifts and opportunistic purchases of full or partial property rights, there is a risk that the resulting mosaic of conserved resources may not represent a coherent set of public values and benefits. With different public and private entities engaged in land conservation, one would further expect that each organization would apply separate goals and criteria to the selection and acquisition of its conservation portfolio. This set of circumstances raises an important question: what is the aggregate outcome of this land conservation process? Retrospective assessments provide a means of reviewing cumulative historical decisions and elucidating lessons for improving future conservation strategies. This study used GIS-based spatial analysis to examine the relationships of private and public conservation lands in Maine to a variety of landscape metrics in order to determine the degree to which these lands represent core ecological and socioeconomic values that are meaningful to a wide cross-section of citizens. Results revealed that the gains of past conservation efforts in Maine are counter-balanced to some extent by apparent gaps in the existing fabric of conservation holdings. Conservation lands capture a representative sample of diverse habitat, provide a large measure of protection for multiple conservation values and indicators, and offer an unusual mix of outdoor recreational opportunities for residents and visitors alike. Yet, the majority of parcels are relatively small and isolated, and thus do not provide contiguous habitat blocks that offset ongoing processes of landscape fragmentation. Furthermore, the majority of area associated with many of the ecological metrics examined in this report is located outside the boundaries of current conservation holdings. The under-represented metrics identified in this investigation can be viewed as potential targets for new strategic conservation initiatives.

Keywords

Land conservationConservation assessmentLandscape metricsLandscape planningConservation strategiesConservation easementLand trustsWorking forest protection

Abbreviations

MDIFW

Maine Department of Inland Fisheries and Wildlife

MNAP

Maine Natural Areas Program

ME DOT

Maine Department of Transportation

ME SPO

Maine State Planning Office

US FWS

U.S. Fish and Wildlife Service

Introduction

In recent years, state and private land conservation initiatives have grown substantially in North America and have greatly expanded the land area protected through conservation easements and simple fee acquisition (Fairfax and others 2005; Ginn 2005). It is generally assumed by the public that the benefits of these conservation efforts are significant and varied, contributing to valued outcomes such as protection of habitats and threatened species, restoration of degraded ecosystems, and public access to recreational opportunities and “special places”. Unfortunately, few retrospective assessments have been performed to measure the achievements and cumulative indicators of success for the conservation portfolio in a given state or region. For the most part, the literature is dominated by forward-looking assessments in which investigators or land managers develop frameworks, criteria, and/or GIS-based models to identify potential future targets for conservation and protection. In contrast, analytical retrospective assessments of land conservation decisions and patterns are much less common.

Land conservation acquisitions are implemented by diverse public and private agencies with different missions, and are often the result of gifts and opportunistic parcel and easement purchases. Given these circumstances, there is a risk that the resulting landscape mosaic of conserved resources may not represent a coherent overall set of public values and benefits. Retrospective assessments provide a means of reviewing past decisions and choices in order to elucidate lessons that can be applied toward improved decision-making in conservation programs and landscape planning. By combining the strengths of historical assessment (Pressey and Taffs 2001; Dietz and Czech 2005; Haines and others 2008), gap analysis (Scott and others 1987; Jennings 2000), and conservation screening techniques (Lathrop and Bognar 1998; Thomas 2003), land managers and stakeholders are in a better position to formulate comprehensive strategies for future land conservation efforts.

Various tools and criteria have been used in setting priorities for selecting conservation lands and evaluating outcomes of conservation programs. Gap analysis is one approach based on GIS mapping that has been widely applied to identify the elements of species and habitat diversity that are under-represented within existing conserved areas (Scott and others 1987; Jennings 2000; Rodrigues and others 2004). The process of gap analysis involves comparing the distributions of vegetation types of interest and inferred species distributions in relation to current conservation areas. This then provides information to guide further efforts to conserve biodiversity at regional, national, or international scales by identifying “gaps” in the protection of key landscape features.

Scott and others (2001) performed a continental scale investigation to determine the extent to which nature reserves capture the full range of biological diversity in North America. Results indicated that (i) <6% of the coterminous U.S. is located in nature reserves; (ii) these reserves are most frequently found at higher elevations and on less productive soils; and (iii) roughly 60% of mapped cover types have <10% of their area in nature reserves. These findings were interpreted as evidence that the full geographic and ecological range of cover types and species was not represented in the reserve network at the time of the study. In a more recent gap analysis of conservation deficits for the continental U.S., Dietz and Czech (2005) estimated that the majority of 554 ecosystem analysis units within the study area have only low levels of protection and that <5% of the two highest priority categories of these lands are protected.

Focusing on a statewide scale in the northeastern U.S., Krohn and others (1998) conducted the Maine Gap Analysis Project during the period from 1992 to 1997, when conservation parcels represented <6% of state land area. The authors reported that southern Maine contained the highest richness of terrestrial vertebrates, threatened and endangered species, and woody plants, but had only small and scattered conservation holdings. Both the southern and northwestern regions of the state were found to be under-represented by the distribution of conservation lands at that time. It was also concluded that only a small percentage of the state was being managed for maintenance of biodiversity and long-term ecological processes.

In their analysis of conservation patterns in western New South Wales (NSW), Pressey and Taffs (2001) used five measures to assess the effectiveness of a system of 22 wildlife reserves that originated during the period 1960 to 1997. After tabulating the number and extent of these reserves, they examined how well various land systems were represented among reserves, the efficiency or proportion of the reserve system contributing to conservation targets set for each land system, and vulnerability bias (i.e., the extent to which reserves occur in parts of the region with the highest risk of vegetation loss). Results indicated that representativeness was low, efficiency measures reflected limited success in meeting conservation targets, and vulnerability values were equivocal, suggesting that areas at risk were not afforded any greater protection than other areas. The authors concluded that improvements were needed for future strategic planning and decision making regarding reserves in NSW.

Haines and others (2008) proposed an assessment approach based on using estimates of human footprint patterns as a means of documenting the outcomes of landscape conservation efforts. The human footprint has been described by Sanderson and others (2002) as a spatial GIS-based depiction of anthropogenic features and impact areas associated with those human features. The methodology uses various measures of anthropogenic activities that affect natural communities in an effort to determine whether implemented conservation strategies are effective in mitigating or reducing the size and impact of the human footprint in a given area or region.

Several authors have examined land conservation activities from the perspective of asking how much land must be protected to meet measurable conservation objectives (e.g., Fahrig 2001; Tear and others 2005). This important question remains unresolved, but is generally thought to have a number of possible answers. Using simulation models, Fahrig (2001) determined that the amount of habitat requiring protection was a variable function of the population biology of target species and the interplay of both quantitative and qualitative landscape features. Tear and others (2005) suggested that setting targets for amounts of protected lands requires identifying shared values among stakeholders and experts, and then applying core principles and scientific standards to establish measurable objectives.

Land Conservation in Maine and Objectives of this Study

There is a great tradition of land conservation in Maine that dates back to the early part of the Twentieth Century and continues into the current period of vigorous conservation activity across the state. The roots of formal public conservation efforts in Maine can be traced to 1919, when Charles Elliot, George Dorr, John D. Rockefeller Jr., and other wealthy benefactors joined in celebrating the establishment of Acadia National Park on the coast of Maine at Mt. Desert Island. That event was followed in 1931 by Governor Percival Baxter’s donation of land to form the core of Baxter State Park in north-central Maine. Since then, Acadia National Park has grown to include over 162 km2 (40,000 acres), while Baxter State Park has expanded to include almost 830 km2 (205,000 acres) of protected land.

More recently, the Land for Maine’s Future (LMF) Program was initiated in 1987 with a public bond of $35 million for land acquisition that resulted in over 283 km2 (70,000 acres) of conservation projects. By the end of 2006, LMF had received another $62 million in bond funding and had helped to conserve a total of 1800 km2 (445,000 acres). In the private sector, the Nature Conservancy (TNC) commenced operations in Maine some 40 years ago and as of 1996, held roughly 413 km2 (102,000 acres) in easements and fee. Since then, TNC purchases and partnerships have resulted in over 4047 km2 (1 million acres) of lands protected by easements and fee purchase. Between the years 1987 to 2006, total conservation lands in Maine increased from <5% of state land area to 17% of state land area. Many of these gains were made possible by the significant shift in forestland ownership as large multi-national paper manufacturers divested their lands to a host of new ownership categories, including real estate investment trusts (REITs) and timber investment management organizations (TIMOs) (Hagan and others 2005; Ginn 2005).

The goals of previous and ongoing land conservation activities in Maine have varied as a function of the agencies and organizations involved. For example, the Maine Department of Inland Fisheries and Wildlife (MDIFW) designed and implemented a Comprehensive Wildlife Conservation Strategy (MDIFW 2005) to conserve habitat for priority fish and wildlife species of greatest conservation need. The LMF Program uses a ranking system of criteria and point values based on the natural or disturbed condition of a parcel, its accessibility, regional context and proximity to other public lands, the degree to which a parcel represents a significant need or gap in terms of location and land use category, and whether the property has an unusual single exceptional value. Maine TNC uses a strategic framework based on their concept of “conservation by design” (TNC 2006), which incorporates eco-regional assessments aimed at conserving the abundance, geographic distribution, and biodiversity of species and ecological systems in the region.

Given the striking recent trend in land conservation activity across its varied landscape, Maine provides a textbook opportunity for assessing what values and public benefits have been protected by these conservation efforts, as well as what gaps are evident in the current fabric of conservation lands in the Maine bioregion. Here, we present a GIS-based retrospective assessment to determine what has been accomplished and what lessons have been learned over the last 20 years of land conservation efforts in Maine, a period of time that directly tracks the first two decades of the LMF Program (Barringer and others 2004). The major objective of this investigation was to examine the geographic extent and distribution of private and public conservation lands in the state, and then to determine the degree to which these protected lands represent core ecological and socioeconomic values or indicators that are meaningful to a broad cross-section of citizens and interests.

Methods

In our assessment methodology, conservation lands were defined as those areas where development, or other land uses deemed incompatible with conservation objectives, are prohibited or are very strongly limited through ownership control or deed restrictions. Thus, areas that are protected only by state and/or federal regulations—such as many shoreland zones and wetlands—were not included in our definition of conservation lands, unless those areas were also located on parcels where the land was protected through some form of conservation ownership. Two methods dominate the land conservation process—fee simple acquisition by a public or private entity, and the purchase of development rights via a conservation easement resulting from negotiations between willing buyers and sellers. Given the wide diversity of public and private interests and goals, easements may specify a range of legal conditions. For example, many conservation easements in New England permit continued forest management. These “working forest” easements typically allow timber harvests and may include provisions for construction of roads and establishment of portable sawmills. Depending on circumstances, easements may or may not include public access and recreational use.

Analyses for this landscape assessment of conservation lands were performed using ESRI ArcMap version 9.2. Considerable time and effort were invested in obtaining the most current and accurate GIS data layers for this assessment. For our base layer map, we initially examined the conservation lands layer from the Maine Office of GIS (MEGIS) and found that data were incomplete. We subsequently obtained and adopted a more complete map layer that had been prepared by Maine TNC (Dan Coker, personal communication). Using that improved map layer, we were able to account for 94% of known conservation lands. Other data layers were obtained from the best public sources available and are listed in Appendix 1. For each map layer, careful quality assurance procedures were followed in an effort to confirm the reliability, accuracy, and completeness of each data set. Many of the maps had gaps or errors that required corrections, were published at various dates ranging from 1983 to 2008, included map data with varying degrees of accuracy (Stehman and others 2003; Sader and Legaard 2008), and in some cases, incorporated best available opportunistic observations, rather than systematic sampling data. Map layer projections were generally UTM Zone 19, NAD 1983.

In this assessment of conservation lands, we attempted to use a wide variety of mapped ecological, environmental, and socioeconomic indicators or metrics to determine the natural and cultural values and conditions that are represented or under-represented in the protected lands. Using a step-wise approach, we examined on a state-wide basis the intersection of conservation lands with successive map layers representing indicator metrics, mapped the results, and then tallied numerical percentages or areas associated with each metric. Given the close relationship between conservation lands and ecological features, as well as the predominance of ecological spatial data, most of our assessment metrics were ecologically focused. Socioeconomic metrics were less well represented in existing secondary data sources and were largely focused on recreational uses, provision of ecosystem services, and forest products.

Results

Current Status of Conservation Lands in Maine

As of 2006, conservation lands accounted for 14,864 km2 (3.67 million acres) or 17% of the state land area of 85,998 km2 (21.25 million acres) (Table 1; Fig. 1). The conservation status of those lands was apportioned into 45% fee ownership and 55% conservation easements (Table 2; Fig. 2). Whereas the state is the largest fee owner of conservation lands (at >3966 km2 or 980,000 acres), land trusts hold easements on almost 6880 km2 (1.7 million acres) and account for almost 8498 km2 (2.1 million acres) of total conservation lands. Currently, the largest share of conservation lands protected through both ownership and easements is that portion held by non-profit land trusts and conservation organizations (57%), followed by the state (35%), the federal government (5%), and municipalities (3%). Most of these holdings are concentrated in north-central, eastern, and western Maine in areas located away from population centers (Fig. 1); as a result, many counties contain only a small percentage of the conservation acreage (Table 3). The size distribution of conservation parcels within the state is characterized by a steep exponential decrease from smallest to largest (Table 4), with small parcels <0.4 km2 (100 acres) representing 72% of the total, whereas large contiguous parcels >4.0 km2 (1000 acres) represent 8% of total parcels.
Table 1

Total area of public and private conservation lands in Maine

 

1993

2006

Increase

Area (km2)

Area (acres)

Area (km2)

Area (acres)

Federal

707 (16%)

174,787

787 (5%)

194,416

+11%

State

3,405 (79%)

841,440

5,184 (35%)

1,281,018

+52%

Land trusts

145 (3%)

35,862

8,439 (57%)

2,085,200

+58 Xa

Municipal

82 (2%)

20,389

455 (3%)

112,349

+5.5 X

Total area conserved

4,340

1,072,478

14,864

3,672,984

+3.4 X

Values in parenthesis indicate the percentage of total land area held by each ownership category in 1993 and 2006. Values from 1993 were estimated by Richard D. Kelly, Maine State Planning Office

aThe symbol X indicates a multiplication factor of 58 times the previous area

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Fig. 1

Distribution of federal, state, and private conservation lands in Maine

Table 2

Conservation status of public and private conservation/recreation lands in Maine as of 2006

Category

Fee

Easement

Total

km2

Acres

km2

Acres

km2

Acres

Federal

740

182,906

46

11,510

786

194,416

State

3,967

980,291

1,217

300,727

5,184

1,281,018

Municipal

455

112,323

0.1

26

455

112,349

Land trusts

1,560

385,353

6,879

1,699,848

8,439

2,085,200

Total

6,722

1,660,873

8,142

2,012,110

14,864

3,672,984

Values are numbers of square kilometers or acres of land area recorded as fee purchase or easement

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Fig. 2

Fee ownership and easement status of protected conservation lands in Maine

Table 3

Percent of total public and private conservation acres in each Maine county

County

%

County

%

Androscoggin

0.2

Aroostook

17.5

Cumberland

0.6

Franklin

3.8

Hancock

4.4

Kennebec

0.4

Knox

0.5

Lincoln

0.2

Oxford

6.8

Penobscot

6.1

Piscataquis

27.2

Sagadahoc

0.4

Somerset

16.6

Waldo

0.5

Washington

13.5

York

1.4

Table 4

Size frequency distribution for all conservation land parcels in Maine

Parcel Size

Parcel Size

Number of parcels in that range

km2

Acres

0–0.04

0–10

1,512

0.04–0.4

11–100

1,195

0.4–4.0

101–1,000

743

4.0–40

1,001–10,000

222

40–400

10,001–100,000

72

400–4,000

100,001–1,000,000

5

For each of the increasing order-of-magnitude size ranges, the numbers of conservation properties of that size are indicated

Conservation holdings have increased dramatically over the last 15–20 years (Table 1). From 1993 to 2006, federal lands increased by 11%, state conservation lands increased by 52%, land trust holdings increased by a factor of 58, reported municipal holdings went up by a factor of 5.5, and the entire state-wide portfolio of conservation lands rose by a factor of 3.4 times. Properties that were added to Maine conservation lands with leveraged support from the LMF Program tallied 1800 km2 (445,000 acres) at the end of 2006 (Fig. 3a, b), and these collective acres were protected at a modest state bonding expense of $40,030/km2 or $162/acre ($72 million total). LMF-supported parcels and investment dollars were distributed across multiple counties as summarized in Table 5. The level of overall voter support for the LMF conservation program can be gauged by the fact that 63–69% of voters in Maine’s 500+ voting districts approved the 1987, 1999, 2005, and 2007 bond initiatives that funded the LMF Program. Moreover, roughly 80% of these municipalities supported the LMF bond in 2007.
https://static-content.springer.com/image/art%3A10.1007%2Fs00267-010-9481-7/MediaObjects/267_2010_9481_Fig3_HTML.gif
Fig. 3

(a) Distribution of conservation lands co-funded by the LMF (Land for Maine’s Future) Program during the period from 1987-2006; (b) enlarged map of southern Maine showing smaller LMF parcels

Table 5

LMF-supported conservation lands in fee or easement status that occur in each Maine county, along with the value of LMF and matching funds invested in those lands by county

County

Total Land

Fee (%)

Easement (%)

LMF

Match

km2

Acres

Androscoggin

12.1

2,992

82

18

$1,168,281

$673,752

Aroostook

26.3

6,511

54

46

$1,704,725

$874,975

Cumberland

37.0

9,153

39

61

$9,040,988

$15,682,423

Franklin

87.9

21,715

99

1

$3,862,764

$5,005,990

Hancock

150.4

37,177

38

62

$6,248,395

$14,086,631

Kennebec

29.6

7,321

97

3

$3,120,637

$3,290,401

Knox

2.5

630

62

38

$809,750

$1,902,821

Lincoln

4.3

1,069

79

21

$3,029,462

$1,744,588

Oxford

5.1

1,260

814

446

$1,273,583

$1,036,131

Penobscot

138.6

34,238

23

77

$2,619,712

$4,011,814

Piscataquis

808.7

199,828

16

84

$12,386,319

$21,636,709

Sagadahoc

7.7

1,908

84

16

$1,625,500

$4,458,111

Somerset

191.4

47,291

100

0

$1,621,989

$19,939,836

Waldo

1.2

292

100

0

$948,625

$200,225

Washington

237.1

58,583

83

17

$14,801,105

$24,783,169

York

60.5

14,954

40

60

$7,629,512

$7,128,439

Total

1,800

444,923

44.4

55.6

$71,891,346

$126,456,014

Funding percent

    

36.2

63.8

For each county, the percent of LMF-supported conservation land in fee or easement is indicated

LMF Land for Maine’s Future Program

Ecological Values and Conditions

Conservation lands in Maine include a wide variety of cover types, habitat conditions, and ecological values, reflecting the diversity of landscape conditions existing in the state (Fig. 4). Cover type analysis indicated that 83% of conservation lands are forested, containing either mixed forest (28%), evergreen forest (27%), deciduous forest (16%), or forest regeneration (12%). Forested and emergent herbaceous wetlands represent 8.8% of conservation acreage, compared with 8.5% wetland cover for the state as a whole. Overall, the proportional representation of land cover types across the entire acreage of conservation lands was remarkably close to the fractional distribution estimated for the state as a whole (Fig. 5)—thus, conservation lands broadly reflect the mix and proportions of cover types in Maine. The major exceptions were evergreen forest cover, which was over-represented on conservation lands, and agricultural lands, which were noticeably under-represented in the conservation portfolio.
https://static-content.springer.com/image/art%3A10.1007%2Fs00267-010-9481-7/MediaObjects/267_2010_9481_Fig4_HTML.gif
Fig. 4

Distribution of land cover types in Maine. In order to avoid obscuring cover type patterns, outlines of conservation lands were omitted from this map. Please refer to Fig 1 for the locations of conservation lands

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Fig. 5

Percentages of land area within major cover type categories in the state of Maine, compared with land cover percentages for all conservation lands

Land cover diversity varies considerably among current conservation parcels, ranging from single to multiple cover types (Table 6). As might be expected, there is a strong relationship between size and diversity among the parcels. Thus, the larger parcels that collectively constitute >80% of total acreage in conservation holdings exhibit eight or more cover types per parcel and therefore contribute substantially to the overall mosaic of landscape diversity.
Table 6

Frequency distribution of cover types per conservation parcel expressed in terms of the number of parcels and the total conservation area associated with each category of cover type diversity

Cover type diversity (# cover types/parcel)

# Parcels

km2

Acres

Percent of total conservation land

1

855

11.3

2,802

0.09

2

482

20.0

4,944

0.14

3

473

59.9

14,813

0.43

4

469

184.9

45,678

1.34

5

439

423.1

104,547

3.06

6

355

786.9

194,431

5.69

7

269

1,189.2

293,845

8.60

8

206

3,368.9

832,447

24.36

9

99

5,233.6

1,293,229

37.84

10

31

2,551.4

630,460

18.45

Many have used threatened and endangered species as a target or indicator for purposes of conserving sensitive habitats, and this ecological metric was similarly applied in this analysis of the Maine bioregion. However, in order to use this type of metric, it was necessary to examine multiple raster and vector-based map layers from various sources that each contained only partial coverage of the entire list of threatened and endangered taxa. Results from this analysis were complex and sometimes inconsistent. At a general level, GIS point data indicated that 40% of the 1,700 mapped locations for threatened and endangered animal species in Maine occur on protected conservation lands (Fig. 6). As a next step, these target species were screened to select a subset identified by MDIFW (2005) as high and highest priority Species of Greatest Conservation Need (SGCN) in Maine. Out of 47 SGCN bird species mapped with raster-based habitat suitability models (Appendix 2), 61% were under-represented in terms of the proportion of suitable habitat located on conservation lands (e.g., upland sandpiper—Bartramia longicauda), whereas 13% of the species were over-represented in terms of the fraction of suitable habitat on the same lands (e.g., Bicknell’s thrush—Catharus bicknelli). Using these two bird species as examples, 1% of suitable habitat for upland sandpiper and 52% of the mapped suitable habitat for Bicknell’s thrush are on conservation lands. It is important to note that 10 out of the 47 SGCN bird species were also mapped with point data representing direct field observations, and those results were not fully consistent with the habitat suitability data. For example, sedge wren (Cistothorus platensis) was under-represented on conservation lands based on habitat models, but was over-represented on the basis of mapped field observation points. In the case of the iconic SGCN species—bald eagle (Haliaeetus leucocephalus)—results of habitat suitability models for this raptor indicated a 16% overlap with conservation lands, whereas point data indicated that up to 40% of bald eagle nests occur on those lands (Fig. 7). Out of 27 SGCN insects and invertebrates mapped with point data from field observations, more than 30% of the species were under-represented (e.g., tidewater mucket—Leptodea ochracea and yellow lampmussel—Lampsilis cariosa), whereas 50% or more were over-represented (e.g., Clayton’s copper—Lycaena dorcas claytoni and twilight moth—Lycia rachelae) on conservation lands (Appendix 2).
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Fig. 6

Locations of designated habitat for animal species listed as threatened, endangered, or of special concern that occur inside or outside of conservation lands in Maine

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Fig. 7

Locations of bald eagle nests in relation to conservation lands in Maine

Results revealed that prime habitats for inland waterfowl and wading birds identified by MDIFW occur on approximately 7% of conservation lands, and this conservation acreage represents roughly 19% of the entire area mapped as inland waterfowl and wading bird habitat in the state. Although spatial data targeting occurrences of larger mammals such as deer, moose, and bobcat were not readily available, we were able to obtain a recent map from the U.S. Fish and Wildlife Service (2009) showing revised critical habitat designated for Canada lynx (Lynx canadensis). Based on that GIS layer, it was estimated that 23% of the habitat designated for lynx within Maine intersects conservation lands (Fig. 8), with the remainder largely distributed on private working forest lands. Other data indicated that approximately 10% of deer (Odocoileus virginianus) wintering areas mapped by the Beginning with Habitat Program (BWH) and MDIFW occur on conservation lands, and that this land area represents 3% of total conservation acreage. As another assessment indicator, we examined the distribution of old growth forest stands that were listed or recommended for listing by the Maine State Planning Office (1983). Results indicated that approximately one-third of those stands are located on conservation lands.
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Fig. 8

Critical habitat for Canada lynx in relation to conservation lands

Selected locations in Maine have been identified for conservation priority as Focus Areas of Statewide Ecological Significance by BWH scientists in cooperation with the Maine Natural Areas Program and MDIFW. Analysis of this data layer indicated that roughly 22% of existing or potential Focus Areas occur on conservation lands in the state.

Given the valuable mix of aquatic resources represented by lakes, streams, and ponds in the Maine landscape, one might ask how these waters have fared in relation to other parts of the conservation portfolio. Results indicated that conservation lands in Maine contain 4,621 miles of river and stream channels, which amounts to 15% of total river and stream length within the state. From the perspective of watershed protection, we examined the extent to which conservation lands encompass measurable proportions of specific watersheds within the state. Out of 22 watersheds designated as Hydrologic Cataloging Units in Maine, there are 5 in which conservation lands protect at least one-third (33–47%) of the watershed area. However, for 13 of the remaining 17 major watersheds, only 1–10% of each drainage area is protected as conservation land.

An analysis was performed using a map of the Northern Appalachian/Acadian Ecoregion produced by the Wildlife Conservation Society of Canada that focused on areas identified as the largest and wildest remaining in the region. Results indicated that conservation lands in Maine intersect 37% of the area designated as the “Last of the Wild” within the state.

Physical Geographic Values and Conditions

Physical geographic attributes of conservation lands were analyzed using several metrics. Results indicated that the majority of conservation land acreage (78%) is concentrated in 5 out of the 15 biophysical areas in Maine (Fig. 9), with the largest distributions in the Aroostook Hills (22%), Central Mountains (16%), Boundary Plateau (15%), Western Mountains (13%), and Eastern Interior (12%). Topographic relief varies among conservation lands, but is weighted toward higher elevations. The distribution of acreage by elevation includes 37% above 366 m (1,200 ft), 28% at 244–366 m (800–1,200 ft), 11% at 152–244 m (500–800 ft), 16% at 61–152 m (200–500 ft), and 8% at elevations <61 m (200 ft). In geologic terms, more than 75% of conservation land acreage is underlain by glacial till and glacial moraines, and roughly 10% of conservation lands occur on calcareous or limestone bedrock and the richer soils that are associated with these geologic substrates.
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Fig. 9

Distribution of conservation lands in relation to biophysical regions in Maine

Cultural and Economic Values

Roughly 75% of conservation lands occur in four Maine counties—Piscataquis, Somerset, Washington, and Aroostook—whereas population is concentrated elsewhere in other counties located in the southern and coastal portions of the state. Conservation lands near population centers in southern Maine tend to be small scattered parcels, reflecting the constraints of existing development, parcel fragmentation, and higher protection costs for both acquisition and easements (Fig. 3b). Large parcels are concentrated in areas of low population, reflecting lower acquisition costs and the legacy of large, unbroken land holdings that have progressively become available as the forest industry has divested its lands (Hagan and others 2005; Lilieholm 2007).

For the 12 largest Maine communities located from Bangor southward to Biddeford that contain 25% of the state’s population, there are 285–925 conservation parcels (totaling as much as 488 km2 or 120,490 acres) within 48 km (30 miles) of each municipality (Table 7). Within a 96.5 km (60 mile) radius of each municipality, there are anywhere from 1265 to 2199 parcels of conservation land totaling as much as 2724 km2 or 673,060 acres (Fig. 10). Population “service centers” in Maine with the lowest and highest numbers of conservation acres within a 48 km (30 mile) radius are Kittery (103 km2 or 25,405 acres) and Greenville (2222 km2 or 549,035 acres), respectively.
Table 7

Conservation parcels and acres within 48 km (30 miles) and 96 km (60 miles) of Maine’s largest municipalities

Community

Population (2006)

Parcels within 48 km

Area within 48 km

Parcels within 96 km

Area within 96 km

Portland

63,011

925

282 (69,730)

1,622

730 (180,315)

Lewiston

35,734

746

260 (64,250)

1,998

1,365 (337,415)

Bangor

31,008

290

488 (120,490)

1,967

2,724 (673,060)

South Portland

23,784

898

279 (69,000)

1,577

711 (175,645)

Auburn

23,156

812

362 (89,350)

2,106

1,480 (365,785)

Brunswick

21,915

794

236 (58,400)

2,199

1,007 (248,835)

Biddeford

21,898

845

266 (65,630)

1,424

618 (152,640)

Sanford

21,534

738

237 (58,505)

1,265

583 (144,185)

Augusta

18,560

716

233 (57,540)

2,052

1,519 (375,425)

Saco

18,289

915

299 (73,840)

1,499

676 (167,165)

Westbrook

16,201

888

299 (73,760)

1,633

751 (185,490)

Waterville

15,639

285

140 (34,550)

1,939

1,627 (402,110)

Area values are km2 with acres in parenthesis (out of a total of 14,864 km2 or 3.67 million acres of conservation lands)

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Fig. 10

Locations of conservation lands in relation to 48 km (30-mile) and 96 km (60-mile) radii surrounding major population centers in Maine

For recreational “gateway” communities in Maine, access to nearby conservation lands is a potentially important factor enhancing tourism and quality of life (Governor’s Council on Maine’s Quality of Place 2007). Assessment results indicated that there are 5 gateway communities in Maine with over 4047 km2 (1 million acres) of conservation lands within a 96.5 km (60 mile) radius—these include Ashland (5,190 km2 or 1,282,408 acres), Greenville (11,953 km2 or 2,953,551 acres), Jackman (5,442 km2 or 1,344,683 acres), Lincoln (5,240 km2 or 1,294,697 acres), and Millinocket (6,263 km2 or 1,547,551 acres).

Scenic travel corridors are important elements of Maine’s tourism infrastructure and these features were examined as a part of this assessment. Results indicated that 16% of the total miles designated in Maine’s National Scenic Byways and All-American Roads pass through the 17% of the entire state currently identified as conservation lands. Thus, these special transportation routes are not over or under-represented as a feature in the conservation landscape.

Maine’s conservation lands provide a broad range of socially valued ecosystem services that contribute to clean air and water, wildlife habitat, flood and erosion control, and related amenities (Brookings Institution 2006). One specific example of ecosystem services is the role that conservation lands play in protecting the state’s drinking water. Out of 60 municipal water supply areas covering 2014 km2 (497,585 acres) that have been mapped by the Maine Department of Human Services Drinking Water Program, a total of 689 km2 (170,320 acres), or more than one-third, lie within conservation areas.

Many conserved areas are part of the state’s “working landscape”—areas that support the production of timber, animal forage, and agricultural crops. These traditional land uses provide many economic benefits to rural communities through jobs and income, and serve an important role in maintaining community character and cultural identity (NEFA 2007; Lilieholm 2007). Working landscapes also provide valuable habitat for a variety of wildlife species. We examined the locations of Maine’s primary wood processors (e.g., sawmills, pulp and paper manufacturers, wood pellet mills, and biomass-fired electrical generating stations) in relation to conservation lands. Mills along the border with Canada and New Hampshire were also included in the analysis. Using a 96.5 km (60 mile) haul radius centered on each wood processor to depict each mill’s potential supply area, it was possible to determine the fraction of forested conservation acreage located within that distance of any of the mills and the number of mills that might potentially compete for the same forest resources (Fig. 11). Results indicated that virtually all of the forested conservation lands are located within a timbershed serving one or more of the mapped mills. In fact, 50% of the conservation acres in upland forest cover are within 96.5 km (60 miles) of 32 or more wood processors, although it is unclear exactly how many of those conservation acres represent working forests.
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Fig. 11

Locations of wood processing mills in Maine. The degree to which forested conservation lands intersect the 96 km (60-mile) haul radii of these mills is indicated by a scale of red (high overlap by many mills) to green (overlap with fewer mills). Not shown, but included in the rankings, are mills in Canada and New Hampshire with haul radii that intersect Maine forest lands

Roughly 5.0% of the state is broadly classified as agricultural land cover, including crops, pastures, and fields, whereas only 0.5% of conservation lands are classified into those categories. This under-representation of the agricultural working landscape is reflected further with data for prime crop soils. Although the soils map for Maine has a gap of 12,546 km2 (3.1 million acres) in the northern part of the state, the mapped portion of Maine contains 11,736 km2 (2.9 million acres) designated as prime agricultural soils and farmland of statewide importance. Only 4% of those designated soils, or 516 km2 (127,610 acres), occur within conservation lands.

Administrative Indicators

Conservation lands operate within a complex matrix of land ownership, ranging from large industrial timberlands in the north, to small privately-owned family forests in more densely populated areas of the south. Many protected lands and large expanses of undeveloped forest lands are located within the 42,088 km2 (10.4 million acre) jurisdiction of Maine’s Land Use Regulation Commission (LURC) in northern Maine (Fig. 12), rather than under the umbrella of local control. These lands are afforded additional protections under LURC’s mission to preserve public health, safety, and welfare; to encourage multiple-use of natural resources; to promote orderly development; and to protect natural and ecological values (Bley 2007). One of the important ongoing administrative developments for working forest lands within the LURC jurisdiction is the emergence of three 3rd party environmental certification programs that are fostering sustainable forest management on roughly one-third of the state land area.
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Fig. 12

Location of Maine conservation lands in relation to the Land Use Regulation Commission (LURC) jurisdiction within the state

As noted previously, much of the progress in land conservation within the state has been driven by land trusts. In 2006, approximately 117 land trusts operated in Maine, and 101 of those were local organizations operating exclusively within the state. Land trust offices are concentrated in southern Maine and along the coast, primarily in areas of high population density (Fig. 13). Nearly 45% of these local land trusts are located in just two counties—Cumberland and York (Table 8).
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Fig. 13

Distribution of private land trust offices within the state of Maine

Table 8

Numbers of local land trusts operating in each Maine County as of 2006

County

# Land trusts

County

# Land trusts

Androscoggin

1

Aroostook

2

Cumberland

25

Franklin

5

Hancock

5

Kennebec

2

Knox

5

Lincoln

9

Oxford

5

Penobscot

8

Sagadahoc

3

Somerset

3

Waldo

4

Washington

5

York

19

  

Discussion

Overview of Assessment Findings

Land conservation activity increased substantially across Maine during the last 20 years, with total acreage protected by fee ownership (45% of acres) and conservation easements (55% of acres) growing to 17% of state area as of 2006. How representative was that process of land selection and what types of assets were protected by the chosen parcels? In this assessment, we examined the degree to which important conservation criteria and public values are represented within the cumulative portfolio of conservation acreage in the state.

Based on multiple indicators or metrics, it is apparent that current conservation lands provide relatively strong representation for a range of biodiversity values and natural conditions, and even offer an extra measure of protection for a number of parameters. For example, suitable habitats for a number of SGCN birds and invertebrates appear to be over-represented on the 17% of state area in conservation status. Several other related metrics exhibit more of a neutral relationship, with 19% of inland waterfowl and wading bird habitat, 17–22% of habitat for several SGCN species, 22% of BWH Focus Areas, and 23% of critical habitat for Canada lynx located within the bounds of conservation lands. Finally, a number of ecological metrics are under-represented, with only 10% of deer wintering areas, 15% of stream and river corridors, and 0 to 13% of habitat mapped for selected high priority SGCN species on conservation lands (Table 9; Appendix 2).
Table 9

Examples of land conservation metrics that are under-represented or have skewed distributions in Maine conservation lands

Landscape parameters

 Agricultural lands and prime agricultural soils

 Deer wintering areas

 Watershed protection

 Stream and river corridors

 Two-thirds of the 15 major biophysical areas

 Lower elevations <244 m

 Three-quarters of Maine counties

 Close proximity to population centers for day-use of conservation lands

 Larger conservation parcels, especially in southern Maine

SGCN birds and mammals

 American black duck (Anas rubripes)

 American oystercatcher (Haematopus paliatus)

 American woodcock (Philohela minor)

 Arctic tern (Sterna paradisaea)

 Bald eagle (Haliaeetus leucocephalus)

 Baltimore oriole (Icterus galbula)

 Blue-winged warbler (Vermivora pinus)

 Canada warbler (Wilsonia canadensis)

 Chestnut-sided warbler (Dendroica pensylvanica)

 Common tern (Sterna hirundo)

 Common loon (Gavia immer)

 Eastern meadowlark (Sturnella magna)

 Field sparrow (Spizella pusilla)

 Greater scaup (Aythya marila)

 Louisiana waterthrush (Seiurus motacilla)

 New England Cottontail (Sylvilagus transitionalis)

 Northern flicker (Colaptes auratus)

 Pied-billed grebe (Podilymbus podiceps)

 Prairie warbler (Dendroica discolor)

 Purple sandpiper (Erolia maritima)

 Razorbill (Alca torda)

 Red knot (Calidris canutus)

 Roseate tern (Sterna dougallii)

 Ruddy turnstone (Arenaria interpres)

 Sanderling (Crocethia alba)

 Sedge wren (Cistothorus platensis)

 Semipalmated sandpiper (Erolia pusilla)

 Upland sandpiper (Bartramia longicauda)

 Whimbrel (Numenius phaeopus)

 Whip-poor-will (Caprimulgus vociferus)

SGCN invertebrates and reptiles

 Eastern box turtle (Terrapene carolina)

 Northern black racer (Coluber constrictor)

 Arrow clubtail (Stylurus spiniceps)

 Cobra clubtail (Gomphus vastus)

 Frigga fritillary (Boloria frigga)

 Scarlet bluet (Enallagma pictum)

 Sedge darner (Aeshna juncea)

 Tidewater mucket (Leptodea ochracea)

 Yellow lampmussel (Lampsilis cariosa)

SGCN plants

 Small whorled pogonia (Isotria medeoloides)

If a metric is under-represented, its occurrence on conservation lands is less than would be expected for the 17% of land area represented by conservation lands in the state

SGCN Species of Greatest Conservation Need in the high and highest priority categories based on Maine’s Comprehensive Wildlife Strategy (2005)

Viewed from another perspective, assessment results indicate that the majority of the land area associated with most of the ecological metrics occurs outside of current conservation lands in Maine. For example, 60% of all mapped point locations for threatened and endangered species, 85% of stream and river corridors, and 99% of upland sandpiper habitat occur on private lands outside fee and easement conservation lands. This implies that there is a large opportunity for further expansion of conservation efforts to increase the proportion of these ecological indicators that are protected by fee and easement measures.

It is important to note here that conservation lands, as defined in this assessment, are complemented in varying degrees by lands that receive some level of protection by state and federal natural resource regulations. For example, in addition to wetlands that specifically occur on conservation lands, virtually all larger wetlands and significant vernal pools are protected from development by state and federal regulations. Thus, these habitats essentially represent de facto conservation lands over and above the acreage designated on our conservation map. Mandatory shoreland zoning regulations in Maine further restrict development and land use near major rivers and water bodies, thus providing a measure of potential protection for these riparian zones. In both of these examples, however, the degree to which the sensitive regulated lands are protected for conservation purposes may vary as a function of local enforcement, legal variances, and legislative changes over time. This implies that long-term resource protection based on regulatory tools may sometimes not meet expected performance standards. Nevertheless, wetlands, shorelands, and other natural resources that are subject to state and federal regulations contribute in important ways to the mix of lands with some form of conservation status.

At a landscape scale, all major cover types in the state—with the exception of croplands, pastures, and fields—are proportionally represented in conservation lands. In terms of habitat diversity, two-thirds of conservation parcels contain 3 or more cover types, half of the parcels contain 4 or more cover types, and one-quarter of the parcels contain 6 or more cover types. The geographic distribution of conservation properties is concentrated in 5 of 15 biophysical regions, and two-thirds of the acreage is at higher elevations above 244 m (800 ft). Watershed protection ranges widely from 1 to 47% conserved land within each of 22 Hydrologic Cataloging Units in Maine, but for the most part, only a small percent of each watershed is conserved in some fashion. The size distribution of conservation parcels is dominated by smaller properties <0.4 km2 (100 acres) each that comprise almost three-quarters of the total list of conservation holdings. Many of these smaller blocks are dispersed throughout southern Maine, where there is a notable absence of larger conservation parcels. For the state as a whole, the 6 largest protected parcels constitute 24% of all conservation lands and are located in the northern part of the region.

Cultural values, socioeconomic benefits, and recreational opportunities are represented in the matrix of conservation lands at a variety of scales and levels of apparent return on public investment. In general, the largest percentage of conservation lands is concentrated in north-central, eastern, and western Maine in rural forested areas located away from major population centers. As such, the majority of these land holdings are not readily accessible for day use activities by most citizens in the state, although vast areas of conservation lands are available for extended recreational visits associated with camping and seasonal vacation trips.

Throughout the state, conservation lands provide a wide range of ecosystem services and natural amenities that are often overlooked, but which enrich and sustain the quality of life in the region. For example, many of the seasonal homes and camps in Maine are located near areas rich in conservation lands, reflecting the strong affinity of the public for the natural and cultural values associated with these landscapes. A number of recreational gateway communities are located within 96.5 km (60 miles) of roughly one-third of all conservation lands. Based on their locations, these communities receive the economic benefits of visitors seeking recreational and vacation activities associated with conserved landscapes. Finally, many protected areas are also part of the state’s “working landscape”, providing timber, agricultural production, and other traditional land uses that benefit rural communities through jobs, income, community character, and cultural identity.

Adopting a Strategic Approach

There is clear and compelling evidence from this assessment of the positive achievements of past conservation efforts in Maine. However, these success stories are counter-balanced to some extent by remaining gaps in the current fabric of conservation holdings. Existing conservation parcels capture a representative cross-section of diverse habitat within the state, provide a large measure of protection for a wide range of conservation values and indicators, and offer an attractive mix of outdoor recreational opportunities for residents and visitors alike. On the other hand, the majority of parcels are relatively small and isolated, and thus do not contribute to contiguous habitat blocks that offset landscape fragmentation. Moreover, the limited size of many protected areas leaves them too small to sustain even minimally viable populations of most species. Thus, land use activities on adjacent properties may adversely impact both habitat integrity and species diversity on these protected lands. As a final concern, it can be noted that the majority of land area associated with the ecological metrics described in this report is located outside the boundaries of current conservation lands.

Looking ahead, we suggest that future land conservation efforts in Maine should adopt a coordinated and comprehensive state-wide planning strategy to address several key areas of need, including those noted in Table 9. For example, efforts should be made to connect smaller isolated conservation fragments into large contiguous networks linked by protected stream corridors and wetland habitats. Another way to compensate for the potential threats to small area reserves is to encourage conservation partnerships aimed at promoting compatible land use practices on lands adjacent to protected parcels. High value habitats for threatened and endangered species could be targeted for conservation, and larger parcels of mixed habitat could be added to the conservation portfolio in the central and southern portions of the state that are closer to population centers. Stream and lake resources could be given higher priority for conservation easements aimed at curbing shoreland development and increasing public access to recreational opportunities. Where possible, new strategic planning efforts should build upon previous conservation blueprints and action plans that have been prepared for the northern Appalachian/Acadian ecoregion (TNC 2006) and for Maine (MDIFW 2005). Already, steps in this direction are being coordinated through the Maine Land Trust Network, the new state-wide conservation easement registry, and other working groups (New England Governors Conference Inc 2009).

Future conservation initiatives should realistically assess fiscal constraints on private land conservation, given that funds are generally too scarce to protect all of the lands and resources that are deemed worthy. In this context, conservation strategies should evaluate existing regulatory frameworks and allocate funding resources to areas and needs where legal regulations are unlikely to provide adequate protection for public conservation values. There are numerous state and federal laws, sanctioned by the U.S. Constitution and supported by dozens of Supreme Court decisions, that provide a sound basis for regulating private land to protect public interests in wetlands, shorelands, listed species and their habitats, air and water quality, and the like (Freyfogle 2003). Where current laws are deficient, new or revised statutes are needed—for example, vernal pool protection was recently added to wetland regulations in Maine. Where inadequate enforcement undermines the public interest, efforts should be directed toward improving compliance (Briggs and others 2008). Ultimately, the purchase of lands and easements should complement the environmental outcomes expected as a result of existing statutes and ordinances.

The Growing Use of Conservation Easements

More than half of the conserved lands in Maine are protected via conservation easements, a less-than-fee-simple approach to conservation that has grown in popularity in recent years. Conservation easements typically run in perpetuity and may include provisions ranging from strict preservation of natural features, to conditions that preclude development but allow continued timber harvests. The increase in the use of conservation easements has greatly expanded the extent of protection that could be afforded under the more traditional fee simple approach. Yet this reliance on easements also raises important questions.

One issue of potential concern is public access, a legal provision that is absent in many easements, perhaps because the easement would otherwise not be acceptable to the private landowner. As an example, Maine’s largest current easement—the 3,000 km2 Pingree Easement in northwestern Maine—does not specify free and open public access. Although requiring public access could undermine some conservation acquisitions, this legal provision warrants further careful consideration, given that the sale of easements typically generates significant tax advantages for the seller. Already, lands protected with LMF co-funding require public access in their conservation easements.

Other questions about the permanency of easements and the ability to amend or to revise easement language in response to changing socioeconomic and ecological conditions are also being examined (McLaughlin 2005, 2006). With widespread adoption of easements as a protection tool, careful monitoring will be required to ensure legal protection in perpetuity. As a step in this direction, Maine revised its Conservation Easement Act in 2007 to require mandatory registration of all conservation easements—both new and existing—in a state-maintained database. This conservation easement registry will allow greater transparency, assist in the writing of improved legal language, and allow local tax and real estate appraisers to assess the value of easement lands more effectively. On the downside, such transparency could fuel development pressures on adjacent parcels that might benefit from proximity to permanently-protected amenities. By nature of their de facto exclusive zoning, protected areas may attract amenity-based development around their periphery. This phenomenon is already well underway near many National Parks and National Forests in the Western U.S. (Stein and others 2007), and even adjacent to protected areas in developing nations (e.g., Kenya’s Nairobi National Park).

Considering Future Development Scenarios

Where possible, we recommend that land conservation programs should consider spatially-explicit forecasts of future development trends in an effort to anticipate land use change, with the goal of protecting high-value parcels and landscapes before they are sold for private development purposes. Considering development risks is a special concern for several reasons. First, development fragments ownerships and parcels, and fuels rising land costs—factors which greatly complicate landscape protection. Identifying important ecological lands that are likely to become development targets before such pressures arise is a proactive strategy that minimizes confrontation and saves both political and financial capital. Such a process can potentially even create de facto urban growth boundaries—a difficult outcome to achieve politically, but one that can arise organically through the voluntary actions of willing buyers and sellers pursuing common conservation interests. When forecasting future development, it is important not only to identify where development pressures are likely to emerge, but also where development should emerge. Indeed, identification of areas with suitable soils near existing infrastructure as sites favorable for development can help to forge a shared vision between conservation and economic development interests. Thoughtfully executed, this approach saves taxpayers from absorbing the costs of expensive unplanned growth. Alternative conservation tools should also be considered, including performance zoning, mixed use, mandatory open space dedications, and use of transferable development rights (TDRs) that can channel development to suitable areas, while compensating landowners in protection zones (Lilieholm and Romm 1992).

GIS-based alternative futures analyses (Hunter and others 2003; Baker and others 2004; Busch and others 2005; Stein and others 2005) offer significant opportunities to move beyond reactive and/or opportunistic conservation approaches toward a more proactive and strategic approach that anticipates future development and maximizes the investment of limited conservation resources. Frustrating such efforts, however, is the limited quality and availability of GIS spatial data, particularly data intended for socioeconomic and cultural analyses. Even where digital spatial data exist, the errors and gaps in many maps are sufficiently large that analytical outcomes are compromised. Further investment will be needed in these data bases.

Significant challenges exist and it is important to recognize that the nature of protection afforded conservation lands can vary considerably. Outcomes will inevitably depend on a number of factors, including landowner management practices and local enforcement of environmental regulations. Future conservation efforts should continue to explore voluntary and compensatory protection through fee acquisition and easements, targeting protections to areas where the line that separates private and public rights in land are uncertain.

Acknowledgments

This investigation was supported by funding from the Senator George J. Mitchell Center for Environmental and Watershed Research at the University of Maine, the Sustainability Solutions Initiative (National Science Foundation Grant EPS-0904155), and the Maine Agricultural and Forest Experiment Station. We greatly appreciate the kind and generous assistance of Daniel Coker at the Maine Chapter of The Nature Conservancy, Janet Parker at the Maine State Planning Office, and Bethany Atkins at BWH in providing data for this assessment. We also thank Professors William Krohn and Steven Sader at the University of Maine for their thoughtful and constructive internal reviews, and four external reviewers for their perceptive insights and suggestions.

Copyright information

© Springer Science+Business Media, LLC 2010